Hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) shows high potential for patients with oropharyngeal cancer. Dental implants can cause substantial artifacts in the oral cavity impairing diagnostic accuracy. Therefore, we evaluated new MRI sequences with multi-acquisition variable-resonance image combination (MAVRIC SL) in comparison to conventional high-bandwidth techniques and in a second step showed the effect of artifact size on MRI-based attenuation correction (AC) with a simulation study.max) in the tumor was calculated for increasing artifact sizes centered over the second molar.Twenty-five patients with dental implants prospectively underwent a trimodality PET/CT/MRI examination after informed consent was obtained under the approval of the local ethics committee. A conventional 3D gradient-echo sequence (LAVA-Flex) commonly used for MRI-based AC of PET (acquisition time of 14 s), a T1w fast spin-echo sequence with high bandwidth (acquisition time of 3.2 min), as well as MAVRIC SL sequence without and with increased phase acceleration  were applied. The absolute and relative reduction of the signal void artifact was calculated for each implant and tested for statistical significance using the Wilcoxon signed-rank test. The effect of artifact size on PET AC was simulated in one case with a large tumor in the oral cavity. The relative difference of the maximum standardized uptake value  to MAVRIC 481 mm2  and to MAVRIC-fast 486 mm2 . The relative reduction in signal void was significantly improved for both MAVRIC and MAVRIC-fast compared to T1 FSE . The relative error for SUVmax was negligible for artifacts of 0.5-cm diameter (−0.1%), but substantial for artifacts of 5.2-cm diameter (−33%).The absolute reduction of signal void from LAVA-Flex sequences to the T1-weighted fast spin-echo (FSE) sequences was 416 mmMAVRIC-fast could become useful for artifact reduction in PET/MR for patients with dental implants. This might improve diagnostic accuracy especially for patients with tumors in the oropharynx and substantially improve accuracy of PET quantification. In head and neck tumor staging, computed tomography (CT) and magnetic resonance imaging (MRI) play an important role in the evaluation of local tumor extension, since clinical and endoscopic examination often results in underestimation of disease, as deep infiltration of the surrounding tissues can be hard to detect -3. GenerThe two main problems for MRI of the oral cavity are patient motion and artifacts of dental alloys due to magnetic susceptibility artifacts . To reduConventional strategies to optimize the image quality close to metal implants are a high bandwidth per voxel, 3D spatial encoding, a high-resolution matrix, and a multiecho spin-echo (SE) sequence or turbo/fast SE sequence .The relatively new multi-acquisition variable-resonance image combination (MAVRIC) as well as the slice encoding for metal artifact correction (SEMAC) technique has shown very promising results in reducing susceptibility artifacts in arthroplasty imaging -27. MAVRmax in PET images after MRI-based AC.Given the good results of MAVRIC in arthroplasty imaging, we investigated this technique for its capability to depict the oral cavity in the presence of metallic dental implants by comparing artifacts in MRI datasets acquired with FSE, standard MAVRIC SL, and a MAVRIC-fast with an increased phase acceleration allowing a shorter repetition time (TR), resulting in notably shorter acquisition time. Furthermore, a simulation study was performed to calculate the effect of different artifact sizes on maximum standardized uptake value SUVThis prospective study was conducted with patients referred for FDG PET/CT who gave written informed consent for additional MRI scans during the FDG uptake time. Patients were included if they had dental implants and did not have any contraindication for MRI. Between September 2013 and January 2014, 25 patients  were included. The study was carried out with the approval of the local ethics committee. Examinations were performed using a sequential trimodality PET/CT-MRI system consisting of a GE Healthcare Discovery 750w 3T MRI and a GE Healthcare Discovery 690 PET/CT  . A shuttThe in-phase images of a dual-echo gradient-echo pulse sequence  with TR 4.3 ms, echo time (TE) 1.3 ms, a matrix size of 288 × 224 with a spatial resolution of 1.7 × 2.2 × 4.0 mm; covering a field of view of 50 cm, using a bandwidth of 142.86 kHz, with an acceleration factor of 2 and a total acquisition time of 14 s) commonly used in whole-body MR imaging for AC of PET images were used as a reference ,30. A 2Da1 and the corresponding orthogonal diameter a2 were measured by a board-certified radiologist [IAB]. The area of the artifact was calculated by assuming the shape of the artifact to be elliptical using the equation A = π × (a1/2) × (a2/2), with A meaning the area of the ellipse.The signal void was quantitatively assessed for every implant using a commercially available viewing workstation (GE Advantage Windows 4.4). On the axial images of all four sequences, the largest diameter The qualitative image analysis was performed by two board-certified radiologists . Both compared the four sequences independently and assessed the delineation of anatomical details of the oral cavity on a five-point scale with 1 = good depiction of anatomical structures, 2 = structures visible with slight blurring, 3 = oral cavity visible with substantial blurring, 4 = oral cavity only partially visible, and 5 = oral cavity not assessable. Furthermore, the image quality was assessed for spatial blurring and image noise on a five-point scale: 1 = no artifacts, 2 = barely visible artifacts, 3 = visible artifacts without diagnostic impairment, 4 = diagnostic impairment, and 5 = severe artifacts, non-diagnostic . HyperinBased on the assessment of spatial blurring on LAVA-Flex sequences, two groups were generated: group 1 with low to moderate artifacts (categories 1 to 3) and group 2 with blurring artifacts impairing diagnosis (categories 4 and 5). Differences in qualitative data  were compared for T1-FSE and MAVRIC-fast between both groups.To estimate the effect of artifact size on PET quantification if MRI sequences are used for AC, we performed a simulation analysis for one patient with a large carcinoma in the right tonsil. Therefore, artifacts of various sizes were artificially inserted into the AC atlas routinely used for the PET/MR reconstruction. The simulated artifacts were created by inserting a spherical volume into the image and setting the signal to 0 within the volume. The artifacts were all centered over the second molar in the right maxilla and spherical in shape with increasing diameters from 0.5 to 5 cm. The difference between the baseline image, without artifact, and each reconstructed image with an artificial artifact was calculated. The normalized difference between the baseline PET and artifact-corrected PET was used to produce a contour map showing the percentage difference from baseline in each area of the image.p < 0.05). Absolute and relative reduction of artifact sizes were calculated for T1-FSE, MAVRIC SL, and MAVRIC-fast sequences and compared using the Wilcoxon signed-rank test. Differences in scores for the qualitative data  were compared using the Wilcoxon signed-rank test. Significance level was set at a p value of <0.05. Agreement between the two readers was determined using Cohen's kappa, with κ values of 0 indicating poor agreement, 0.01 to 0.2 slight agreement, 0.21 to 0.40 fair agreement, 0.41 to 0.60 moderate agreement, 0.61 to 0.80 good agreement, and 0.81 to 1 excellent agreement [Statistic evaluation was performed with statistical software . The LAVA-Flex sequence was used as a reference. Differences in signal void areas were assessed with the Wilcoxon signed-rank test  and average weight of 74 kg (range 44 to 109 kg). Image quality and acquisition were acceptable for all patients.2 on axial images was observed on LAVA-Flex sequences and could be reduced to 195 mm2 for T1-FSE sequence to 131 mm2 for MAVRIC SL and to 126 mm2 for MAVRIC-fast (Table The largest artifact size of 612 mm2) than that for MAVRIC SL with a mean of 481 mm2 or MAVRIC-fast with a mean of 486 mm2 (p < 0.001). There was no statistically significant difference between the absolute reduction of MAVRIC SL and MAVRIC-fast (p = 0.064)  and −78% (p < 0.001), respectively (Table p = 0.017).The relative artifact reduction with T1-FSE showed a mean of −62%. Both MAVRIC SL and MAVRIC-fast improved the artifact reduction compared to T1-FSE with a mean of −75%  and 3.64 (±0.81) for anatomic distinction, 3.96 (±0.74) and 4.00 (±0.71) for blurring, and 3.84 (±0.47) and 3.68 (±0.63) for image noise, for readers 1 and 2, respectively (Table p = 0.011). For anatomical distinction or spatial blurring, there was no relevant difference between MAVRIC SL and MAVRIC-fast.There was an increase in image noise for MAVRIC-fast compared to MAVRIC SL for both readers, reaching statistical significance for reader 2 (p < 0.001) or MAVRIC-fast (mean 1.36 (±0.63) and 1.40 (±0.65), p < 0.001). Anatomical distinction was overall slightly better for MAVRIC-fast compared to T1-FSE. However, both readers rated image noise significantly better for T1-FSE compared to MAVRIC SL and MAVRIC-fast (p < 0.001).Regarding spatial blurring, T1-FSE had substantially more artifacts with a mean of 2.64 (±0.76) and 2.84 (±0.80) than MAVRIC SL (mean 1.36 (±0.64) and 1.44 (±0.65), On 23 (92%) of the images of the LAVA-Flex sequence, the artifacts by the dental alloys showed multiple hyperintense rings . For image quality, inter-observer agreement is good to excellent regarding blurring (κ = 0.69 to 0.93) and moderate to excellent for image noise (κ = 0.54 to 0.89)  Table .p = 0.102) in group 1. For group 2, MAVRIC-fast led to only barely visible artifacts , while T1-FSE showed artifacts impairing diagnostic accuracy in four cases with a mean of 2.8 and 3.0, respectively  blurring artifacts on LAVA-Flex sequence (group 1) and patients with extensive to non-diagnostic blurring (group 2) was performed. For both readers, there was no significant improvement of spatial blurring with MAVRIC-fast compared to T1-FSE  . This is also a significant improvement compared to the artifact reduction accomplished by a T1-FSE sequence with large bandwidth (−62%). There was a very broad range of signal void sizes for all sequences, due to the various sizes and compositions of the dental alloys . For pats) Table .MAVRIC-fast was optimized to reduce the acquisition time of the conventional MAVRIC SL sequence protocol for potential integration into a whole-body PET/MRI protocol. By increasing the phase acceleration from 2 to 3, the echo train length (ETL) was reduced. As susceptibility artifacts increase with echo time , this ti. The size of signal voids might not translate into identical signal voids on MR attenuation maps; however, a substantial reduction of artifact size will also generate smaller signal voids on MR attenuation maps. The impact of artifact size on PET values could be shown in our simulation study, where artifacts of 19 cm2 lead to an underestimation of SUVmax of 33%, in a tumor nearby the inserted artifact. In our patient population, artifact size was up to 27 cm2 for LAVA-Flex but only 8.9 and 8.8 cm2 for MAVRIC SL and MAVRIC-fast, respectively. Nevertheless, the presented MRI sequences could not completely reduce artifacts from dental implants and also will not take into account the true attenuation from metal implants, teeth, or bones.There was only one patient with hyperintense signals due to dental implants distorting MAVRIC SL/MAVRIC-fast images, while T1-FSE images had this artifact in 12 cases (48%). Such artifacts can lead to non-interpretable images and misdiagnoses; it is therefore favorable to reduce them as much as possible. Furthermore, MRI data are used for AC of PET data in PET/MRI hybrid systems. High image quality without substantial signal voids is favorable for AC . For CT-In addition to a potential improvement of CT-based AC , MRI alsOne limitation of this study is that we could not investigate the alloy composition of the dental implants and had no information of their exact material. Therefore, the influence of different materials on the artifacts in the applied sequences could not be addressed. However, this is the most realistic clinical situation, as patients usually are not aware of the exact composition of their dental implants. A further limitation is a certain uncertainty for measurements that might lead to a slight variability in measured sizes of signal voids and that we only compared vendor-specific sequences and could not investigate SEMAC or compare MAVRIC with SEMAC. Also, volume-selective 3D multispectral imaging (VS-3D-MSI), a fusion of SEMAC and MAVRIC technique, has been reported to provide excellent artifact suppression. In dental imaging, SEMAC reduced artifacts from dental alloys composed of high-susceptibility materials of more than 50% compared to conventional SE sequences . It mighIn summary, this is the first study showing that MAVRIC-fast could be integrated into whole-body PET/MRI imaging for patients with large signal voids due to dental alloys. MAVRIC SL reduced artifact size and increased precise anatomic delineation of the oral cavity. This reduction should improve the accuracy of PET quantification - since large signal voids lead to substantial SUV underestimation. With MAVRIC-fast, acquisition time was kept reasonably short, slightly worsening image noise but further reducing artifact size compared to T1-FSE or MAVRIC SL. Therefore, MAVRIC-fast could be integrated into the diagnostic imaging work-up for head and neck cancer evaluation in patients with dental alloys and potentially also improve AC.


Shivering is a frequent complication following surgery and anaesthesia. A large variety of studies have been reported that nefopam may be efficacious for the prevention and treatment of perioperative shivering. Regrettably, there is still no conclusion of the efficacy and safety of nefopam for the prevention of perioperative shivering. The aim of this analysis is to evaluate the efficacy of nefopam for the prevention of perioperative shivering in patients undergoing different types of anaesthesia compared with placebo group and other active interventions.PubMed, EMBASE, Cochrane Central Register of Control Trials were systematically searched for potentially relevant trials. Trial quality and extracted data were evaluated by two authors independently. Dichotomous data on the absence of shivering was extracted and analysed by using relative risk (RR) with 95 % confidence interval (CI). Continuous outcome was abstracted and analysed by using weighted mean difference (WMD) with 95 % confidence interval (CI). Outcome data was analysed by using random effect model or fixed effect model in accordance with heterogeneity.Compared with placebo, prophylactic administration of nefopam significantly reduced the risk of perioperative shivering not only in the patients under general anaesthesia but also neuraxial anaesthesia . As compared with clonidine, nefopam was more efficacious in the prevention of perioperative shivering . Nefopam has no influence on the extubation time .Our analysis has demonstrated that nefopam is associated with the decrease of risk of perioperative shivering following anaesthesia without influencing the extubation time. Shivering is a distressing and frequent side effect during the intra-operative period , which mA large variety of regimens have been demonstrated to be efficacious in the prevention and treatment of postanesthetic shivering, such as α2-agonist , 5, tram2 adrenoceptors [Nefopam, a benzoxazocine substance, is structurally related to orphenadrine and dyphehydramine . Nefopamoceptors .The aim of this review is to investigate the effectiveness of nefopam for preventing perioperative shivering and the influence of nefopam on the extubation time. The secondary aim of this analysis is to compare the efficacy of nefopam with the other active interventions for the prevention of perioperative shivering.The Cochrane Library 2015, Issue 2) by using different search strategies. Potentially relevant randomised controlled trials (RCT) were searched by using search methods found in , EMBASE (1980 - February 2015), Cochrane Central Register of Controlled Trials (CENTRAL) . Some of the included trials were multiple-arm studies. When we extracted the continuous data from these trials, it was necessary to combine multiple groups into a single one. The SD and mean values of the combined group were calculated according to the method of the Cochrane Handbook of Systematic Review of interventions  Table 11.Table 1The risk of bias of the included studies was assessed by using the Cochrane Collaboration’s protocol . The art2 test respectively. When the P value of Q test was greater than 0.10 and I2 was less than 50 %, we regarded it as homogeneity. The subgroup analysis was based on different anesthetic methods, general anaesthesia and neuraxial anaesthesia. Two sensitivity analyses were planned a prior to explore the heterogeneity. First, calculation that used the fixed effects model was repeated by using the random effect model. Second, some trials were retracted from the journal due to ethical reasons. Therefore, analysis was performed with or without these retracted articles. The reporting bias was assessed by visual inspection into funnel plots [Relative risk (RR) with pertinent 95 % confidence intervals (CI) were calculated for binary outcomes. A statistical significance between nefopam group and control group was assumed if the 95 % CI of the RR excluded 1. In the presence of significant heterogeneity, we intended to use random-effect method. If there was not statistically significant heterogeneity, the fixed effect method was used. As an estimate of statistically significant difference between nefopam and untreated control group for continuous variable, we calculated weighted mean difference (WMD) with 95 % CI. If the 95 % CI of WMD did not include 0, we considered that the difference between nefopam and control was significant. Heterogeneity and inconsistency were evaluated by Q and Iel plots . Meta-anThrough electronic searches, snowballing, manual search, contact with the authors, 133 potentially eligible articles were obtained. The detail of flowchart of the studies included in this study was shown in Fig. A total of 124 studies were subsequently excluded. 65 reports were duplicated from different databases. 53 studies were obviously irrelevant trials of this analysis according to the titles and abstracts. One trial was not randomised controlled trials . One triNine eligible randomized clinical trials were eventually included in this analysis, which were published between 1992 and 2013 –34 , therefore data on the incidence of shivering was combined by using the fixed effect model.9 studies reporting on the episodes of shivering finally entered into the analysis, with 474 patients allocated to nefopam group and 320 patients to placebo group. The control group event rate ranged from 16.7 % to 100 %. Overall analysis demonstrated that nefopam was associated with significant reduction in the incidence of shivering as shown in Fig. We applied two sensitivity analyses to the incidence of shivering compared nefopam with placebo.The fixed effect model favoured prophylactic use of nefopam .The random effect model also favoured the administration of nefopam .2There were three articles retracted from published journals due to ethnic reasons. This sensitivity analysis considered the retracted studies.The incidence of shivering was significantly lower in the nefopam group than the placebo group without the retracted articles .Subgroup analysis focused on the different methods of anaesthesia, general anaesthesia and neuraxial anaesthesia, as shown in Fig. General anaesthesia: the RR favoured administration of nefopam .Neuraxial anaesthesia: the RR favoured prophylactic administration of nefopam .Four studies tested on the effect of nefopam on extubation time compared to the control group. When the data was combined, the extubation time in placebo group was earlier than nefopam group. However, the difference between the two groups did not reach statistical significance , the data was presented in Fig. 2 = 0.57, P = 0.75, I2 = 0 %), as shown in Fig. Clonidine was the most frequently tested substance. Three studies reported on the risk of shivering comparing nefopam with clonidine in total of 407 patients, with 276 allocated to nefopam group and 131 to clonidine group. When the data was combined, the risk of perioperative shivering was significantly lowered in patients received nefopam in comparison with clonidine . There was no statistical heterogeneity between nefopam group and clonidine group . According to all of the enrolled studies, nefopam was not associated with the increase of the risk of any serious side effect, which contribute much to its safety. None of the included studies reported on any side effect of nefopam. This is inconsistent with the previous reports , 39, 40.It is encouraging that nefopam may possess a specific shivering effect. Alfonsi et al. has shown that nefopam caused a small increase in the core temperature by lowering the shivering threshold and without influencing sweating and vasoconstriction thresholds, therefore minimizing heat loss . WhereasThere are several limitations in our analysis. Firstly, the methods of reporting the scores of perioperative shivering were different between the trials in this analysis, most of the included studies used Wrench et al. evaluation , meanwhiIn conclusion, we have demonstrated that nefopam inhibit perioperative shivering without producing hypotension and sedative of α-2 agonist and respiratory influence of opiates. The better prophylactic antishivering efficacy of nefopam and the side effects of other interventions suggest that among all the interventions, nefopam may hold the best promise. However, side effects of nefopam need to be investigated. Besides, direct comparison of nefopam with other drugs, such as tramadol, meperidine is stillke needed to confirm the relative efficacy.


When studying animal behaviour within an open environment, movement-related data are often important for behavioural analyses. Therefore, simple and efficient techniques are needed to present and analyze the data of such movements. However, it is challenging to present both spatial and temporal information of movements within a two-dimensional image representation. To address this challenge, we developed the spectral time-lapse (STL) algorithm that re-codes an animal’s position at every time point with a time-specific color, and overlays it with a reference frame of the video, to produce a summary image. We additionally incorporated automated motion tracking, such that the animal’s position can be extracted and summary statistics such as path length and duration can be calculated, as well as instantaneous velocity and acceleration. Here we describe the STL algorithm and offer a freely available MATLAB toolbox that implements the algorithm and allows for a large degree of end-user control and flexibility. Studies of animal behaviour in open environments yield rich datasets. While behaviour can often be summarized through simple measurements , these measures are not always sufficient. A widely-used solution to this problem was introduced three decades ago, with a methods paper describing the use of video recordings to study animal behaviour . AlthougThe challenge of visualizing movements within a two-dimensional image is not new. Although many solutions have been discussed , none inOur second goal was to obtain path data, specifically x- and y-coordinates of the animal at each time point. While solutions for this purpose already exist, many have drawbacks. EthoVision , our impAnimal research was conducted in accordance with Canadian Council on Animal Care guidelines and with approval from the University of Alberta Animal Welfare Policy Committee. Pigeons (Columba livia) were kept on a 12:12 h light:dark cycle with light onset at 6 AM. Birds were housed individually in metal cages and kept at 85% of their free feeding weight on a diet of Kee Tee pigeon pellets and vitamin supplement. Water and grit were available ad libitum.Columba livia) entering an arena, moving to and eating from four food cups, and returning to the starting box. The STL image allows the researcher to observe the behaviour  without needing to watch the video. This is particularly useful as videos are often longer in duration than the movement; in this particular trial, the raw video lasts 45 sec., while the pigeon is only visible for 25 sec. The STL image inHere we present a spectral time-lapse (STL) image and describe the algorithm used to create the image.Video data was acquired using a standard video camera connected to a PC running Microsoft Windows 7  and recorded as a MPEG-2 transport stream file using the WinTV hardware and software package . . We converted the video to an uncompressed AVI format using MPEG Streamclip , but other software could be used as well. These uncompressed AVI files can be read directly into the STL toolbox.Video shows a single trial of a pigeon (Columba livia) entering an arena, moving to and eating from four food cups, and returning to the starting box.Click here for additional data file.The steps comprising the STL algorithm are illustrated ini-th frame is sampled (sampling), as video is often acquired at higher rates than needed for the STL image. For instance, the animal’s position might be sampled at 1 pps, whereas video cameras often record at 24 or 30 frames-per-second (fps). If the original video speed has been adjusted, such as videos originally from a high-speed camera, then this can be accommodated and calculations adjusted (videospeed). The STL toolbox reports the video’s original acquired fps and the STL’s pps. The sampled video frames are converted to grey-scale, as color will be used to code for time. The folder containing the raw video must be specified in the configuration file (path_raw).The raw video file is read in and only everystartFrame,endFrame). An additional MATLAB function called showFrameK is included to facilitate in determining start and end frames.To allow the STL images to be based on only a portion of a video, start and end frames can be specified, (refFrame). The reference will be subtracted from all other frames to isolate the target animal, i.e., the change in the video frame, in the next stage. A moving average is useful when the background changes over time .In this stage, the reference frame is also defined, which is often either the first or last frame of the video, or a ‘moving average’ .Second, the difference image is spatially smoothed to reduce noise. This is implemented by convolving a two-dimensional Gaussian kernel with the given frame. Ideally, the user will calibrate the kernel size to the image, based on the animal’s size, as viewed by the camera, and video resolution  and a dynamic detection of an overlay (cleanWhite). For the pre-made mask, the filename to the mask image must be provided (maskName). For the overlay, any pixels with an intensity value above a set threshold are ignored (white). This is useful if a timestamp or other overlay is hard-coded into the video, as inFourth, irrelevant portions of the frame are masked out to improve the signal-to-noise ratio and later target detection. Two approaches are used to do this, a pre-made static mask (disableTrim). Frames are only retained if they are sufficiently different from the reference, based on thresholds . At this point, only frames containing temporal information about the movement are retained.Fifth, we trim frames from the start and end of the video that did not contain the target; this feature can be disabled by the end user (cmap). A mask is then created such that only pixel intensities that surpass a threshold are retained (threshMask), further removing noise. At this point, the spatial information corresponding to the target has been isolated. The color specific to the given frame is then applied, seeA mapping of time-to-color is created for each of the retained frames. This mapping is adjustable, but usually corresponds to one or two color cycles (oversatCol).All colorized frames are averaged to produce a single frame that is essentially the STL image. To improve color visibility after averaging, the saturation of the averaged frame is amplified (refFrame). To further improve visibility of the colors, we increase the saturation of the reference (oversatRef). Legend bars are added to the image to show (a) actual time, (b) indicate overlapping frames as would occur if the target pauses, and (c) time-specific color mapping. The actual time bar denotes the length, relative to the other bars, of a fixed amount of time, e.g., 1 second (timeBar). The overlap bar is white if the frames overlapped more than a threshold amount (threshAdjac), and is otherwise black. The size of all three bars can also be adjusted (barSize).To produce the final STL image, we overlay the averaged frame on the reference (path_out). The image can also be viewed immediately (showSTL).The final STL image is exported as an image file to the specified folder (doPath), the STL toolbox uses a simple but efficient method to obtain x- and y-coordinates of the target at regular intervals (pathSampling), which is often a higher sampling frequency than used for the STL image. In our example (pathBack).If path analysis is enabled (example  we used threshTrim). A minimum area for the largest centroid (areamin) is also used to re-determine the start and end frames for the path analysis.The path analysis method takes advantage of the same thresholds used in the STL algorithm to isolate the target and remove spatial and temporal noise. The coordinates of the target are determined by calculating the x- and y-coordinates for the center of the largest centroid, after the image has been intensity thresholded . The path image is saved in the same folder as the STL image (path_out). Along with the x- and y-coordinates for each frame, two summary statistics are calculated: total path length and duration. If the pixels-to-meters conversion is specified (px2m), coordinates and path length will be outputted in meters.The obtained x- and y-coordinates for the target across all retained frames can be plotted over the STL or reference image. A color map is applied, along with the STL image, and the marker’s border and arrows can be modified in the configuration (doVel). To reduce noise in these measures, a weighted average is taken across adjacent values (velSmooth). The plot is saved in the same folder as the STL image (path_out).Using the distances travelled between time points, as calculated for the path analysis, we can readily also calculate the instantaneous velocity and acceleration , was downloaded as a MPEG-4 file from YouTube and converted to an uncompressed AVI with MPEG Streamclip. We cropped the video to isolate the maze. As the video represented multiple trials, we chose a video segment from after the mouse had been trained, spanning from 1 min 46 sec to 1 min 59 sec; this temporal trimming was done through the STL toolbox by specifying the start and end frames . Several settings were modified to suit the video, such as the smoothing kernel size, color map cycles, and the target being lighter than the background. We sampled the mouse’s position at 3 pps for the STL image and 30 pps for the path analysis. We plotted the path over the reference frame. The resulting images are presented in The first video, of a mouse in a radial-arm maze (http://www.youtube.com/watch?v=u7LaPjMtmYM). The video was also downloaded from YouTube and converted. Note that this video was recorded using a high-speed camera and had been slowed down by a factor of 10 (as stated in the video’s description). Settings were customized for differences in the video resolution and speed, as well as target size. Here we sampled the ant’s position at 10 pps, for the STL image and 100 pps for the path image. The resulting images are presented in The second video was of an ant in a simple open environment demonstrating scanning behaviour, where the ant is searching for visual landmarks  Toolbox. doi:do.7663 . OverviewThis paper describes a MatLab toolbox for tracking single animals in video data, quantifying basic movement properties , and then displaying overall movement pattern in a single figure using colours to encode animal position at different times. Tracking-Learning-Detection,” Pattern Analysis and Machine Intelligence, 2011). The animal tracker presented comprises an elementary background subtraction approach augmented with masking, thresholding, and filtering methods to extract the location of the animal. As the parameters for these techniques are manually defined, and then held constant across the video, this method seems best suited to laboratory recordings where the environment changes little. For outdoor recordings, where there are likely illumination changes, occlusions etc a more robust tracking method is required e.g. TLD tracker . I foresee this work being of some use to behavioural researchers tracking animals in laboratory settings. Specifically: as the code is available as a Matlab toolbox, it can be easily installed, the parameters tuned for the specific case, and data visualised easily.Specific CommentsThe authors describe a "moving average" reference frame, but do not describe how this is generated exactly. I think expanding upon this point to make it clear to a reader is important.The 3rd step in the Pre-processing algorithm inverts the negative pixel intensities. I think this step could be omitted by taking either a sum-squared or root-mean-square difference between reference and current frame in step 1.is useful if timestamp or overlay is hard-coded in the video". I would have thought this would be removed in the background subtraction step as it is constant across frames?In the 4th step in the Pre-processing algorithm it is stated that the masking method "The mouse data tracks the animal from 1 min 46 seconds until 1 min 59 seconds.  Was there a reason for using this specific portion of the video?I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. In this article, Madan and Spetch describe a tool for monitoring animal movement in an open field that will be extremely useful to many researchers. Not only does the software monitor the animal's path through the environment, it also offers time-based information, and can provide information about velocity and acceleration of the movement over time. MATLAB software is in wide use in behavioral research, and Madan and Spetch have made the STL algorithm freely available in MATLAB. This is the sort of new tool that can lead researchers to ask new questions and to look in new directions to answer current questions. This algorithm will undoubtedly make a significant contribution to our understanding of animal behavior.I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.


Standard imaging modality for the follow-up after prosthetic replacements for musculoskeletal tumor patients has been conventional radiography. This technique is effective in detecting subtle changes in bone adjacent to metal implants, but in many cases, radiographs do not lead to definitive diagnosis of postoperative adverse events such as acute infection, local recurrence of soft tissue tumor or soft tissue local recurrence of osseous sarcoma. Conventional MRI sequences have not been effective due to metal artifacts. In this study, we tried to elucidate the effectiveness of metal artifact suppression using novel sequence, multiacquisition variable-resonance image combination (MAVRIC), after musculoskeletal tumor surgeries.We retrospectively analyzed 5 cases of malignant bone and soft tissue sarcoma patients who were reconstructed with metal prosthesis after wide resection of tumors. Images obtained using MAVRIC and short tau inversion recovery (STIR) were compared side by side. The paired MAVRIC and STIR images were qualitatively compared independently by two specialists for 4 parameters: visualization of bone - implant interface, visualization of surrounding soft tissues, image blurring, and overall image quality. Quantitatively, paired images were reviewed to identify the slice where the metal artifact was maximal, and a region of interest encompassing the implant and surrounding artifact was drawn using Advantage Workstation .2 vs 135.9 cm2).There were no local recurrences that were detected. By utilizing MAVRIC, visualization of the bone - implant interface and visualization of the surrounding soft tissue were significantly improved in MAVRIC compared to STIR. Although blurring was worse on the MAVRIC acquisitions, the overall image quality was still better on MAVRIC. Quantitatively, the area of metal artifact measured using MAVRIC was markedly less compared to STIR (61.4 cmDespite the relatively small number of cases in the present study, our observation strongly suggests that MAVRIC is able to improve the quality of images by decreasing the artifact caused by endoprosthesis, frequently utilized in reconstruction of musculoskeletal tumor patients. Further installments of conventional imaging sequences with the addition of gadolinium - enhancement will enable increased accuracy in diagnosing local recurrences of sarcoma patients. Multimodal therapy for sarcoma patients has improved the prognosis in the past decades, but surgery is still the mainstay of treatment for malignant tumors. Surgery for sarcoma of both bone and soft tissue usually consists of wide resection including the cuff of normal tissue, which leads to large defects. When skeletal structure is compromised, especially near the joint, endoprosthesis is frequently utilized for the reconstruction. Traditionally, radiograph was utilized to detect the change in bone, but it has not enabled the detection of devastating postoperative events such as soft tissue recurrences. The usage of massive metal implants have prevented the usage of magnetic resonance imaging (MRI) which has high spatial resolution and tissue contrasts compared to plain radiographs due to metal artifacts.Recently, improvements in metal composition of prosthesis , 2 and aSince 2014, 4 megaprosthesis  and 1 augmented proximal femoral reconstruction stem were utilized for reconstructions and underwent MR imaging on a 3T scanner . Histological diagnosis included 2 osteosarcomas, 2 chondrosarcomas and 1 synovial sarcoma. There were 4 female and1 male. Proximal humeral implant and reconstruction stem were composed from titanium alloy and all other implants were made up of cobalt-chrome. Conventional short tau inversion recovery (STIR) and MAVRIC sequences were acquired in the coronal planes using similar scan parameters and readout bandwidth. MAVRIC sequences were obtained with a 3T scanner  in the supine position. The protocol included coronal, STIR images  and coronal proton density weighted images  with an 32 – channel torso surface coil. These MR images were retrospectively analyzed between two musculoskeletal tumor specialists (one radiologist and one orthopaedic oncologist) in a matching anatomic plane with the maximal artifact for both qualitative and quantitative variables. Artifact was defined as areas of signal void pile-up or geometric distortion. Images were graded on a five-point scale from −2 to +2, where lower score suggested better outcome for MAVRIC acquisitions, which was previously reported by Gutierrez et al. [2, average: 61.4 cm2) was less compared to STIR . Clinically, MAVRIC was able to detect fluid collection surrounding the implant in one patient. Although the entire body of the patient was swollen and covered with eruption which was suggestive of toxic shock syndrome, thrombotic thrombocytopenia purpura/hemolytic uremic syndrome, or adult stills syndrome, MAVRIC acquisition revealed fluid collection surrounding the endoprosthesis  Fig.  were sigsis Fig. , which lThere are many histological subtypes of sarcoma of both bone and soft tissues, and treatment is increasingly becoming case-specific with the advent of genetic testing. Several molecular targeting agents have been reported to improve the prognosis and many more are set to be reported. Although, these medical therapies are important, almost all sarcomas need some kind of surgical intervention to eradicate the tumor. It is especially important to perform a wide resection of the lesion to prevent local recurrence from the residual sarcoma cells. To reconstruct large defects, several methods have been proposed including endoprosthesis, allografts, autografts, and recycled bone by pasteurization or liquid nitrogen. When the defect is situated around the joint, endoprosthesis is often utilized due to the poor outcome using other reconstruction methods.max of 5.0 or greater might differentiate between tumor and fibrosis (data not shown). But, utilization of CT still causes artifacts due to beam hardening which pose significant challenge in delineating the tumor for successful surgery. Novel method for early diagnosis of postoperative adverse event is imperative to improve the outcome of sarcoma patients.In order to improve the outcome of sarcoma patients, it is important to control the various postoperative adverse events such as acute infection and local recurrence as well as the distant metastasis which is a devastating event both physically and psychologically. Infection leads to multiple salvage operations and delay of chemotherapy which is a poor prognosticator of survival. Local recurrences have been reported to cause higher morbidity due to consequent distant metastasis . One of MRI has improved the prognosis of sarcoma patients by accurately detecting the localization and spread of the tumor prior to operation. It has the highest spatial resolution and tissue contrasts compared to other imaging modalities, but metal implants after surgery have impeded its accuracy by causing artifacts that results from metal disturbing the main magnetic field and inducing strong and spatially - varying local gradients . MRI impA limitation of this study is its relatively small sample size, which is consistent with other past small case series. Although the preparation of images is still time consuming, it is well suited for dedicated application in areas under suspicion. Further improvement, such as the introduction of MAVRIC - T1WI will enable the use of gadolinium - enhancement and increase the sensitivity for small lesions near the metal implants.Several variations of metal artifact suppression technique such as FSE, patient positioning, and use of high bandwidth have been reported , 15–17,


Low-density parity-check (LDPC) codes have been implemented in latest digital video broadcasting, broadband wireless access (WiMax), and fourth generation of wireless standards. In this paper, we have proposed a high efficient low-density parity-check code (LDPC) decoder architecture for low power applications. This study also considers the design and analysis of check node and variable node units and Euclidean orthogonal generator in LDPC decoder architecture. The Euclidean orthogonal generator is used to reduce the error rate of the proposed LDPC architecture, which can be incorporated between check and variable node architecture. This proposed decoder design is synthesized on Xilinx 9.2i platform and simulated using Modelsim, which is targeted to 45 nm devices. Synthesis report proves that the proposed architecture greatly reduces the power consumption and hardware utilizations on comparing with different conventional architectures. Low-density parity-check (LDPC) codes, introduced by Gallager  during tLDPC codes have certain advantages over turbo codes . The first merit is that the decoding of LDPC codes fully follows parallelism which performs at a higher speed. Secondly, very low-complexity decoders are more enough and suitable for these codes. Thirdly, LDPC decoding is verifiable; that is, decoding to a correct code word can be verified for accuracy.Moreover, LDPC codes are more suitable for implementation in applications that employ parallelism. Therefore, these codes can be employed in several standards including WiMax (IEEE 802.16) and different high speed applications in which iterative message-passing algorithms are mostly implemented in parallel. LDPC implements parallelism in the decoding process thereby achieving high decoding throughput. LDPC codes consecutively decode both rows and columns and therefore these codes are more suitable for iterative decoding, hence referred to as iterative decoders.LDPC codes can be represented in two ways. The first method is in the form of matrices, similar to all other linear block codes, and the second way of representation is in the form of graphs. There are several algorithms proposed to decode LDPC codes and each algorithm has been designed autonomously and comes under different names as a matter of fact. Some of the widespread LDPC decoders used commonly are the sum-product algorithm, belief propagation algorithm, and message-passing algorithm.In this paper, a low-complexity Euclidean orthogonal LDPC architecture has been proposed for low power applications. μm CMOS process was reported and the above techniques were implemented to show the effect of power consumption. With early termination, the prototype decoded 10.4 pJ/bit/iteration, while performing within 3 dB of the Shannon limit at a BER of 10−5 and a throughput of 3.3 Gbps. If operated from a 0.6 V supply, the energy consumption can be further reduced to 2.7 pJ/bit/iteration with a total throughput of 648 Mbps, due to the highly parallel architecture.Darabiha et al.  investigMansour and Shanbhag  proposedReviriego et al.  proposedTorrieri et al.  proposedThe low-density parity-check codes for turbo multiuser detection in multipath CDMA channel are designed by Wang et al. . They deThe nonbinary mixed domain LDPC decoders and their finite precision effects were studied by Kim and Sobelman . They usm) LDPC codes. The algorithm has been implemented with low hardware utilizations in VLSI. Their decoding algorithm used a serial architecture for GF(2m) are implemented on FPGA. Their results showed that their algorithm was suitable for short to medium length codes.Spagnol et al.  proposedThe serial GF (64)-LDPC decoder proposed by Boutillon et al.  was baseHwang and Lee  studied The conventional methods in –21 stateThe proposed method of decoder design comprises several processing elements—variable node unit (VNU), check node unit (CNU), address generator, minimum data generator, and several other modules as shown in Data with noise is received from the channel and fed into the check node unit of the LDPC decoder.Euclidean orthogonal generator gets the sequence from the check node unit and enable/disable the variable node unit based on the severity level of the noises on the received sequences.The output from variable node unit is stored in the data storage elements which received the address sequence from the address generator module.Minimum data generator unit generates the minimum 1 and minimum 2 data which are then given to the comparator unit.The response from comparator is added with the response from the subtractor unit to produce the decoded signals.Algorithm of proposed decoding is described in the following.The architecture of the check node unit of LDPC decoder is shown in The gate count of a single multiplier or division module is much more than the gate count of one adder or subtractor unit; hence only adders and subtractors are fully utilized in our design instead of multipliers and division units, thereby reducing the hardware complexity and cost.x”. The hard decision vector “x” is routed to the check node unit or block (CNB) through the routing network, whose size is smaller than the network size of sum-product algorithm. A single-bit value exists for routing between two nodes. The VNU comprises a flip-detection circuit, line buffer, multiplexed adder, and concatenator. At first, the received signal “y” from check node unit passes through a register-feedback assembly to enter the variable node block (VNB). The received values are 6-bit signed-magnitude (SM) values. Let [sn : mn] be nth 4-bit value provided to the nth VNB, where sn denotes hard decision value and mn denotes the magnitude of sn. The correlation calculation is made simpler by SM for implementation and the correlator circuit consists of an inverter followed by a 1-bit multiplexer. The block data received from CNU unit have four subblocks, out of which the first three submodule blocks are processed by adder module and last submodule block is processed directly by multiplexer unit.The variable node unit (VNU) as shown in A value “qc” is produced at every clock cycle and fed to the minimum data generator unit (MDGU) depicted in It is used to determine the level of noise on the received signal as shown in The architecture of LDPC decoder designed in this work is more suitable for low power applications and is verified using Xilinx 9.2i and Modelsim 5.8 on several Virtex family devices. The proposed decoder is simulated on various FPGA devices for its performance analysis. The input for proposed decoder is taken from the real time mobile environment with noises. The clock frequency for the simulation is 200 MHz with 50-50 on-off clock period as initial simulation setup. The designed decoder made use of 100 LUTs and 51 slices with an operating frequency of 200 MHz at the maximum. The results show that this proposed decoder consumes very low power in terms of Look Up Tables, FPGA slices, and gate counts. The power and current consumptions are verified for different devices of the Virtex family and tabulated in The operation of our proposed decoder is illustrated in We have simulated the proposed code and then the proposed LDPC code is downloaded in to the FPGA device for its performance measurement. The power consumption of the proposed LDPC architecture is measured using xprimer or power analyzer tool available in the Xilinx tool. The input to the FPGA unit is given from the real time mobile signal received from the channel with noises. The LDPC decoder proposed in this paper has been compared in terms of power utilizations by evaluating it over different Virtex devices. The LDPC decoder in this work was mainly designed for the purpose of reducing the power levels during operation. Several performance assessment parameters and resource utilization parameters were determined for the proposed LDPC decoder. The current study mainly focuses on low power applications and hence the pipelined LDPC decoder is being designed and developed for this purpose. The proposed LDPC decoding architecture is synthesized using Xilinx project navigator version 9.2i tool. The decoding latency obtained for both check node and variable node unit implementations in the proposed architecture is about 28 ns, whereas the decoding latencies obtained by Kim and Sobelman  and SpagThe proposed architecture consumed 4-input LUTs of about 100, which provides a low hardware complexity compared to Kim and Sobelman  and SpagWe have proposed the design of high efficient LDPC decoder architecture for implementations in low power applications. The design of Euclidean orthogonal generator has been proposed in this paper, which is a part of LDPC decoder architecture. The Euclidean orthogonal generator proposed in this work reduces the error rate of the proposed LDPC architecture. The design discussed produced better results than other conventional decoder architectures with lesser hardware consumption and power utilization of about 27 mW, which is more suitable for most of the low power applications.


The concept of ward culture has been proposed as a reason for the often reported differences in treatment decisions when managing inpatient aggression. We therefore studied whether staff on wards actually shares similar perceptions and attitudes about aggression and whether the specialty of the ward on which the staff members work influences these opinions.The Attitudes Towards Aggression Scale was used to assess attitudes towards aggression in 31 closed psychiatric wards. Altogether 487 staff members working on the study wards were asked to fill in the scale. Respondent’s gender, age, educational level, working experience on the current ward, and specialty of this ward  served as background variables.Most of the variance found was due to differences between individuals. Belonging to the personnel of a particular ward did not explain much of the variance.Psychiatric staff on the wards does not share attitudes on aggression. As each staff member has his/her own opinion about aggression, training for dealing with aggression or violent incidents should be done, at least partly, on an individual level. We also suggest caution in using the concept of ward culture as an explanation for the use of restrictive measures on psychiatric wards. Psychiatric inpatients exhibiting aggressive behavior towards staff or fellow patients are a challenge for clinical management . The proSome studies have stressed the importance of organizational factors in the treatment of inpatient aggression alone  or in coThe concept of ward culture has been proposed as a reason for the often reported differences in treatment decisions when managing inpatient aggression. We therefore investigated whether staff on wards actually shares similar perceptions and attitudes about aggression and whether the specialty of the ward on which the staff members work influences these opinions.This cross-sectional study was conducted in Finland as a part of SAKURA, an extensive research and development project to investigate and reduce the use of seclusion and restraint in Finland and in Japan . It compThe Attitudes Towards Aggression Scale (ATAS) was used to study individual attitudes towards aggression . This 18offensive , communicative , destructive , protective , and intrusive .The ATAS consists of five aggression- related components: The ATAS is regarded as a theoretically conclusive scale that can be used to ascertain differences in attitudes among groups. Earlier research using the ATAS has reported significant differences in attitudes in relation to aggression linked to personnel’s gender  and to fThe data were collected in May 2008. Information about the research was given at nurse managers’ meetings and staff meetings. The questionnaires for the nursing staff were distributed to the wards by three of the researchers, and the questionnaires for physicians were distributed during clinical meetings. The questionnaires were distributed to all of the staff on the wards. To ensure respondents’ anonymity, the wards were supplied with return envelopes and closed containers. After the data collection period, the containers were removed by the researchers.The validity and reliability of the ATAS scale were assessed with Principal Component Analysis with Oblimin rotation and Cronbach’s Alpha correlation. For each aggression-related component, a sum variable was created and these were used for further analyses. Variance analysis was performed using One-way Analysis of Variance (ANOVA). Mean scores of components and standard deviation of means were also calculated.The study protocol for the whole SAKURA research project was duly approved by the Ethics Committee of the Hospital District of Helsinki and Uusimaa. The appropriate authorities in each participating hospital granted separate research permission. The questionnaire was used with the permission of the developer. The participants received oral and written information on the purpose of the study and their rights as respondents. Participation in the study was voluntary and the respondent’s anonymity was ensured in all phases of data collection and analysis.Of the 487 questionnaires distributed, 397 were returned; thus the overall response rate was 81.5%. The ATAS was completed in 361 cases (91.0%). Respondents’ background data are provided in Table The reliability of the scale was good . Barlett’s test of sphericity was conducted, with observed p < 0.001. The KMO sampling adequacy was 0.783, exceeding the recommended value of 0.6 .Using Principal Component Analysis with Oblimin rotation, the items formed five component structures, as in earlier ATAS studies conducted in Europe ,20. CompMost of the variance in attitudes towards aggression seemed to be due to differences between individuals rather than the result of belonging to a group. Using variance analysis, most of the variance found was not related to respondents’ gender, age, educational level, working experience, or specialty of the ward in which the respondent worked .We found the ATAS to be a useful instrument for studying personnel’s attitudes towards aggression. In contrast to earlier research , the posRespondents working on acute psychiatric wards, and to a lesser extent respondents working on rehabilitation wards, emphasized the protective component of aggression, unlike those working in forensic psychiatry. This could be explained as a reaction to having witnessed the instrumental violence that occurs more often on forensic wards than on acute or rehabilitation wards . Also, oWorking experience on the current ward predicted how much the offensive component of aggression was stressed. The longer a respondent had worked on the current ward, the more he/she highlightened the offensiveness of aggression. The reason for this might be that a longer career usually means that an individual has witnessed more violence on a ward. On the other hand, a long career could also result in becoming inured to the communicative and protective features of aggression.In summary, each individual seems to have his/her personal thoughts, views, and attitudes on aggression. Thus, we challenge the concept of ward culture if defined as shared attitudes. People on the same ward tend to work similarly, but this is related more to shared rituals, rules, and management than to socialized thinking. To revise outdated or questionable treatment practices, there is a need for personalized training, management, tutoring, and reflection.We also suggest that the components of the ATAS scale – and the results of this study – are associated with three separate dimensions. The first dimension comprises the idea that aggression can be seen as concrete destructive actions, a widely and uniformly shared opinion among personnel and in society. The second dimension consists of communicative and protective components that highly correlate with each other and represent the “understanding view” of aggression. This dimension seems to be triggered by patients and/or wards, and thus, one could speculate that the understanding of aggression is something related to patients and ward culture. The third dimension represents facets of aggression as dysfunctional behavior and consists of offensive and intrusive components that are interrelated. In the present study, this dimension seemed not to be linked to any known background information, and therefore, it might be related to individual life experiences and arise from respondents’ personal histories or experiences.The strength of this study was the large number of psychiatric wards and staff members. The participation rate can be regarded as reasonable. Unfortunately, almost 35% of the respondents did not provide information about the specialty of his/her ward. From this perspective, the study must be regarded as preliminary.Psychiatric staff on the wards does not share attitudes on aggression. As each staff member has an own individual opinion about aggression, training for dealing with aggressive or violent incidents should be done, at least partly, on an individual level. We also suggest caution about using the concept of ward culture as an explanation for the use of restrictive measures on psychiatric wards.The authors declare no competing interests.TL, ES, HP, and GJ designed the study. TL, ES, and NL collected the data. TL performed the statistical procedures. All authors contributed to the analysis of the data. TL, ES, and NL drafted the manuscript. All authors revised the manuscript and read and approved the final version.


To investigate whether saturation using existing methods developed for 3T imaging is feasible for clinical perfusion imaging at 7T, and to propose a new design of saturation pulse train for first-pass myocardial perfusion imaging at 7T.The new design of saturation pulse train consists of four hyperbolic-secant (HS8) radiofrequency pulses, whose peak amplitudes are optimized for a target range of static and transmit field variations and radiofrequency power deposition restrictions measured in the myocardium at 7T. The proposed method and existing methods were compared in simulation, phantom, and in vivo experiments.In healthy volunteer experiments without contrast agent, average saturation efficiency with the proposed method was 97.8%. This is superior to results from the three previously published methods at 86/95/90.8%. The first series of human first-pass myocardial perfusion images at 7T have been successfully acquired with the proposed method.Magn Reson Med 73:1450–1456, 2015. © 2014 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance.Existing saturation methods developed for 3T imaging are not optimal for perfusion imaging at 7T. The proposed new design of saturation pulse train can saturate effectively, and with this method first-pass myocardial perfusion imaging is feasible in humans at 7T.  Incomplete saturation in the perfusion sequence can result in unintended high signal in the myocardium in perfusion images, which may make it difficult to distinguish a perfusion defect from healthy myocardium. This problem was already observed when transitioning from 1.5T to 3T. Perfusion methods developed at 1.5T were found to operate inadequately at 3T owing to large B0 and B1 variation due to limited capability of commercially available shimming and calibration methods for the heart. Several methods have been proposed to overcome these challenges. Composite adiabatic pulses known as B1-insensitive rotation (BIR4)  ha ha0) andn (BIR4) . A trainn (BIR4) . The disn (BIR4) .standard pulse train). This method is adopted on commercially available 1.5T and 3T systems but has been shown to be susceptible to B1 inhomogeneity at 3T . The coil is an eight-channel strip-line transverse electromagnetic transceiver array . Maximum2; acquisition matrix 192 × 144; slice thickness 8 mm; in-plane resolution 2 × 2 mm2; nominal flip angle 10°; echo time 1.18 ms; repetition time 2.82 ms; receiver bandwidth 1002 Hz/pixel. Generalized autocalibrating partially parallel acquisitions  were recruited. Ethics approval was granted for all study procedures and informed consent was obtained from all subjects.0 shimming over an adjustment volume covering the whole left ventricle (LV). B0 offset was measured with a double-echo gradient echo sequence.Manufacturer provided software was used for B1 shimming (1 over a region of interest (ROI) manually selected in the midventricle short-axis slice covering the LV. The B1 map was determined from images acquired with a B0-independent saturation preparation method  and B1  was then manually selected to cover the aforementioned distribution with a probability greater than 99%.Bribution  in the fse train . A rangeThe online RF-power monitoring system of the scanner was used to determine the maximum energy available for the saturation pulse train. The system monitors RF power averaged in real-time over durations of 0.1/1/10/360 s, and compares it with a set of preset RF power limits. A scan will be stopped automatically when any of the preset RF power limits is exceeded. Each transmit element of the eight-channel coil is connected to an independently controlled RF amplifier and dedicated power monitor. Conservative safety limits are imposed based on SAR simulations for the coil in Semcad X . These worst-case limits assume constructive interference of E-fields everywhere in space. The preset safety limit that is most likely breached is the 1 s limit. For perfusion scans saturating once and collecting one image per heartbeat, the total energy of all RF pulses within 1 s also depends on the heart rate. For a typical heart rate between 50 and 100 bpm, the design of the saturation pulse train needs to allow both saturation and image acquisition to be applied twice within 1 s.The limit of relative energy for a saturation pulse train was obtained using a maximum-amplitude rectangular pulse as the saturation pulse for the perfusion pulse sequence and gradually increasing the duration of the rectangular pulse, in steps of 0.1 ms, to challenge the RF-power monitoring system. The relative energy is defined as the total energy of a set of RF pulses divided by the energy of a 1-ms rectangular pulse of the maximum amplitude.According to the limits measured from eight volunteers and assuming a normal distribution, the limit of relative energy for a saturation pulse train was set to 6. With the limit at this level, the probability of triggering an automatic stop of scan due to excessive energy deposition by the saturation RF pulses is less than 1% at a heart rate between 50 and 100 bpm. This limit would be breached if an 8-ms BIR4 pulse at maximum amplitude was used for saturation.tailored pulse train (0 and B1 variation determined above. Large B0 variation requires RF pulses of broad bandwidth (hence a short duration high voltage pulse), while regions of low peak B1 also increase the demands on the coil voltage. It is difficult to fulfill both requirements with a rectangular pulse of fixed amplitude because its flip angle increases with its duration, but its bandwidth decreases proportionally. No good solution was found in the search for a tailored rectangular pulse train under the conditions at 7T.The development of the saturation pulse train for perfusion at 7T used the same approach adopted for the se train . The fli1 comparable to the B1 range at 7T.Full-passage hyperbolic-secant (HS8) pulses  are more0 offset (±250 Hz) and B1 (150–400 Hz) previously determined from volunteer measurements. T1 and T2 relaxation was ignored. Ideal spoiling was assumed in the simulation, so the transverse magnetization was zero before each RF pulse. Solutions were excluded when the normalized residual longitudinal magnetizationTo minimize the relative energy [The peak amplitudes determined from the search are 29/47/47/84%, respectively, of the maximum amplitude. The relative energy of the HS8 pulse train is 4.9. The probability of a stop of scan triggered by the HS8 pulse train due to excessive RF energy is virtually zero, according to the distribution of the energy limits previously measured from eight volunteers. To complete the HS8 pulse train, each HS8 pulse is interleaved between gradient spoilers , as shown in standard/tailored/hybrid pulse train and the BIR4 pulse) was evaluated in numerical Bloch simulation of the saturation of a single isochromat in the B1 range of 150–400 Hz and B0 offset range of ±250 Hz. The parameters of the five methods are listed in Table 1 and T2 relaxation was ignored and ideal spoiling was assumed.The saturation performance of the HS8 pulse train and four existing methods (the standard/tailored/hybrid pulse train) were also tested in scans of a 10-cm spherical oil phantom (T1 1420 ms). To simulate the B0 and B1 variation, the amplitude of the saturation RF pulses were scaled from 20 to 100% of the maximum, in steps of 10% of the maximum amplitude, and a frequency offset between ±320 Hz, in steps of 20 Hz, was added to all saturation RF pulses. All phantom images were acquired in the same axial plane at isocenter. In each scan, the test saturated image was collected 8 s after an unsaturated image of otherwise identical imaging parameters.The HS8 pulse train and three existing methods . Six 2 × 2 (4 pixels) ROIs were selected at locations of different B1 levels in each image. The normalized absolute residual longitudinal magnetization was then averaged in each ROI. The B1 field over the imaged slice was not homogeneous, so the six ROIs in each image could be selected at locations of desired B1 levels. With the scaling of the amplitudes of the saturation RF pulses, 26 B1 levels, in steps of 10 Hz, in the range of 150–400 Hz were measured.Each test saturated image was divided pixel-wise by its corresponding unsaturated image to calculate the normalized absolute residual longitudinal magnetization, which was then corrected for Tstandard/tailored/hybrid pulse train). As in the phantom scans, two short axis images were acquired in each breath hold, the first unsaturated and the second saturated. The delay between the two images was 8 s. The LV myocardium was manually segmented into six segments . The HS8 pulse train was used for saturation. 60 images were collected, one each heartbeat, over an end-expiratory breath hold. The volunteers were asked to hold breath as long as possible, and then breathe smoothly. The peripheral injection of a contrast bolus  with a power injector  was started between the third and fourth heartbeat. The first image was not saturated.The LV myocardium was manually segmented into six segments. The signal intensities were averaged in each segment. The average intensities from all images except the first one were divided by the corresponding averages from the first image to calculate the normalized signal intensity. The normalized signal intensity was also calculated for the LV blood pool.0 and B1 variation from the same volunteer. In the inferolateral segment the B0 variation is visibly larger than other regions. This is also observed in images from all other volunteers and is consistent with the literature . The maximum residual from the HS8 train was 4.7%, less than the maximum residual from the standard/tailored/hybrid trains at 25.2/13.3/19.2%. 1950 ms . The ave0 and B1 variation targeted by these saturation methods. Previously proposed methods were designed for a higher B1 level and narrower B0 bandwidth. These were appropriate for body coil on 3T scanners but not suitable for the transmitting surface coil on our 7T system. Lower B1 levels require more power for the saturation, however, the RF power deposition allowed at 7T is very limited. This excluded the BIR4 pulse, and limited the number of pulses available for use in all pulse trains. The HS8 pulse and the adiabatic half-passage pulse in the hybrid pulse train are both operating outside adiabatic range at low B1 levels in the targeted range of B1 at 7T, which may explain the relatively high residual normalized signal after the saturation with the hybrid pulse train.With this work, we have developed a new design of saturation pulse train for cardiac perfusion imaging at 7T, and successfully acquired the first series of human first-pass myocardial perfusion images at 7T with the proposed method. In simulation, phantom, and in vivo experiments, we have demonstrated that existing saturation methods developed for 3T imaging are not optimal for cardiac perfusion imaging at 7T. This can be explained by differences in the ranges of B0 offset (±250 Hz) and B1 (150–400 Hz) determined from in vivo measurements had an important role in the design of the HS8 pulse train. No good solution was found in the search for a tailored rectangular pulse train for this range. The duration and frequency sweep of the HS8 pulses were specifically chosen for the above range. The results of the search were sensitive to changes to the range, especially changes to the lower limit of the B1 range. With the lower B1 limit at 140 Hz, no solution was found. At 200 Hz, the required relative energy was reduced to 2.7. Above 235 Hz, the required relative energy was less than 2, enabling coverage of three slices. Reducing the higher limit of the B1 range did not save much energy. With the higher limit at 320 Hz, the saturation still required 4.8 in relative energy. Because the effective saturation bandwidth of the chosen HS8 pulse is mainly determined by its duration and frequency sweep, the results of the search were not sensitive to reduction of the B0 offset bandwidth. With the bandwidth reduced to ±150 Hz, the required relative energy was 4.8. If the range was redefined as an elliptical region spanning ±250 Hz in B0 offset and 150–400 Hz in B1, the required relative energy would be 4.4. The HS8 pulse train proposed in this work (29/47/47/84%) would not saturate effectively if B0 offset and B1 were out of the predetermined range. According to numerical Bloch simulation ignoring relaxation, the maximum normalized longitudinal magnetization immediately after saturation would be 5.6% at B1 of 135 Hz and 0.2% at 415 Hz. If the B0 offset bandwidth was ±300 Hz, the maximum normalized longitudinal magnetization would be 5.4%. Within the range selected in this work, the performance of the HS8 pulse train is not sensitive to small deviations in amplitude of any single HS8 pulse in the pulse train. If the peak amplitude of any single RF pulse in the HS8 pulse train changes by 1% of the maximum amplitude, the maximum change in minimum or maximum normalized longitudinal magnetization will be less than 0.01.The range of B1 field observed in this study, these 5-ms HS8 pulses are not offset-independent adiabatic. The peak amplitudes of the RF pulses of the BISTRO method are not optimized for a target range of B0 and B1 variation, and the BISTRO method requires a sufficiently large number of RF pulses to ensure that all regions experience a flip angle near 90° at least once, which was not required in the design of the HS8 pulse train. In regions of low B1, each single HS8 pulse alone in the HS8 pulse train will not produce a flip angle of 90°, but the combined effect of four HS8 pulses will produce a saturating flip angle.The HS8 pulse train bears an appearance similar to the BISTRO method, both using amplitude- and frequency-modulated RF pulses interleaved between gradient spoilers. The RF pulses used in the BISTRO method have a wide frequency sweep (8 KHz), and they are offset-independent adiabatic. The frequency sweep of the HS8 pulses in the HS8 pulse train in this work is only 1000 Hz. In the low B0 and B1 range but that it deposits slightly greater power into the subject. At low flip angles (short pulse durations), a hard pulse may have similar saturation effects as an HS8 pulse of slightly less power, when the effective bandwidth of the hard pulse is wide enough to cover the target range of B0. An optimized hybrid train of HS8 and hard pulses may be built by replacing low-flip-angle HS8 pulses in the optimized HS8 pulse train with hard pulses of slightly greater power. However, the high-flip-angle HS8 pulses cannot be replaced in the same way, because hard pulses of high flip angles (long durations) will not saturate effectively over the target range of B0. This may explain why no good solution was found in the search for a tailored rectangular pulse train under the conditions at 7T.Other types of numerically optimized RF pulses can also be used to build the saturation pulse train. However, it is difficult to cover the whole universe of RF pulses. We did evaluate a selection of different pulses and found HS8 to be the best. In addition to a pulse train of all HS8 pulses, we also observed in numerical Bloch simulations that a hybrid train of rectangular and HS8 pulses could also saturate effectively in the target BIt should be noted that the imaging protocol used for the rest perfusion scan was not optimized specifically for 7T. The image quality in these first acquisitions is already comparable to that at 3T, supporting the great potential for perfusion imaging at 7T.1 shimming performance. If the lower limit of B1 can be increased to 200 Hz and the upper limit unchanged, the RF energy of the saturation pulse train may be reduced by 43% by simply scaling down the amplitudes of the RF pulses. Alternatively improved B0 shimming would allow the optimization to be performed over a narrower B0 range which would be a second means of reducing RF power deposition. Finally, the RF SAR calculations that we have used are by necessity cautious and future improvements in RF coils and/or RF monitoring technology should allow us to deliver more power into the subject in complete safety. These are all areas of on-going development.Multislice cardiac perfusion imaging at 7T which saturates multiple times in each heart beat remains challenging. According to the relative energy limit allowed for the saturation pulse measured in this study, the relative energy of the saturation pulse train needs to be reduced to 2 if the heart is to be saturated three times each heartbeat. One option may be to improve the B0 and B1 variation and the energy limit at 7T, while the existing methods designed for 3T imaging were not as effective. We also demonstrated that single-slice first-pass myocardial perfusion imaging is feasible for human at 7T.We demonstrated that the proposed HS8 pulse train saturated effectively within the target range of B


The medical ward round is a central but complex activity that is of relevance from the first day of work. However, difficulties for young doctors have been reported. Instruction of ward round competence in medical curricula is hampered by the lack of a standardized description of the procedure. This paper aims to identify and describe physicians’ tasks and relevant competences for conducting a medical ward round on the first day of professional work.M = 8.82 years of work experience) and 12 nurses (M = 14.55 years of work experience) working in different specializations of internal medicine. All interviews were audiotaped, fully transcribed, and analyzed using an inductive-deductive coding scheme.A review of recent literature revealed known important aspects of medical ward rounds. These were used for the development of a semi-structured interview schedule. Medical ward round experts working at different hospitals were interviewed. The sample consisted of 14 ward physicians  contains supplementary material, which is available to authorized users. Conducting an internal medicine ward round is a central, but complex, daily activity in internal medicine inpatient care . Ward roDirectly after their graduation, physicians are responsible for carrying out this complex task. Research reports that physicians struggle in overtaking this task and transitioning to the workplace’s demands successfully –7.With the aim of facing those problems important research was conducted during the last years. It could be shown, that conducting good ward rounds is a complex teachable competence and thus should be integrated in the medical curricula. Simulation-based ward round trainings were identified to be a realistic opportunity to ease the transition from ward round participant to ward round leader, e.g. by gaining important feedback to improve potential deficits . KrautteKnowing that a complex activity like conducting a ward round could be taught, the need for a guiding and assessment tool became obvious. Some important approaches are already made such as “The Basel Standard for Doctorʼs Visits”  or the vTen Cate et al. , 15 defiAs the medical workplace is characterized by a high complexity, the CanMEDs, by the Royal College of Physicians and Surgeons of Canada, provided a helpful basis for characterizing competences around the following six roles of the physician: communicator, collaborator, health advocate, scholar, professional, manager, medical expert .Ten Cate  translatTherefore we referred to the EPA approach to face the complexity of internal medicine ward rounds and the development of a solid assessment.Prior studies already addressed the development of EPAs in different fields of medical education but mainly referred to standardized tasks with a consistent structure and clear responsibilities (e.g. patient handover ). The waWhich competences did prior research suggest as relevant for conducting ward rounds?The qualitative analysis of the interview transcripts shouldWhich competences and sub-competences do ward round experts regard as relevant for a young professional conducting an internal medicine ward round?The results should provide the framework for the interview structure to answer the second research question.How can the competences and sub-competences be integrated into an EPA “Conducting an internal medicine ward round”?provide the scientific framework for the third research question.A three step approach was used to develop a best practice model in an EPA manner:In advance to the main study a review of recent literature was conducted aiming to identify domains of competences relevant for an internal medicine ward round as suggested by prior research. Therefore following key words were included: “ward round”/“round”/“bedside round” in connection with “competence”/“competency”/“skill”/“ability”. The electronic databases PsychInfo, PsychIndex, PubMed and Web of Science were used for the research. In a first step 1760 articles were found that were published after 01.01.1990 and were peer reviewed. In a second step doublings were removed and titles of the papers were screened concerning relevance. The abstracts of the 57 remaining articles were screened. Articles were included when (1) focusing on internal medicine ward rounds and (2) pointing out relevant competences and (3) when based on empirical data or on literature review. Only German and English articles were included. Articles were excluded when the teaching environment of ward rounds was the only focus of the article. In the end ten papers were found to be relevant for the development of the interview schedule. Excerption of the ten articles was summarized and used for the development of the interview schedule.An interview study was conducted using a semi-structured interview schedule for data collection.(i)Questions concerning process and structure of the ward round, to generate a better understanding of the general framework the ward round physician has to be aware of and to generate a common understanding of the ward round the interviewee was referring to.Exemplary questions:How long does the ward round typically take? How does the ward round usually end? (ii)General questions about ward round related tasks and competences, to identify relevant domains of competences from the experts’ point of view.Exemplary questions:What function does the ward physician have in the course of the ward round? Which specific tasks belong to that function?(iii)Specific questions concerning ward round related domains of competences as stressed in prior research, to enhance the understanding of their relevance.Exemplary questions:How would you describe the physician-patient communication in the course of the ward round? How and to what extent you adapt your language use to the patient and/or the ward round team? (If interviewee can’t answer the question: Could you give an example in which adaption of the language is necessary?)To generate a holistic picture of ward round related tasks and competences the interview schedule was subdivided into three parts:The focus of the questions in all three parts was on competences relevant for young professionals. With the usage of open questions in all parts, we allowed the interviewees to add further aspects .Questions in interview part (i) and (iii) focused on the identification of the practical application as well as sub-competences and observable tasks of competences identified in prior research. In part (i), organizational competences are interrogated separately since they were seen as an easy introduction to the interview.The aim of the unstructured questions regarding ward round competences and belonging tasks in interview part (ii) was to identify further domains of competences and to minimalize a potential bias by the interview questions.The interview study was performed with a total of 26 physicians and nurses. They were selected from different care levels , academic teaching hospitals (15)) and different specializations of internal medicine , Cardiology (2), Gastroenterology (3), Haematology/Oncology (7), Immunology/Rheumatology (2), Nephrology (2), Endocrinology (2), Alternating (1)) representing the broad field of internal medicine and the different perspectives of ward round participants. Thus, the interprofessional aspect of ward rounds was reflected and both perspectives were considered for the EPA development. Further the broad fields of internal medicine ward rounds and the various challenges young physicians are facing when conducting ward rounds were covered.M = 8.82 years of work experience (SD = 7.50) and 12 nurses having M = 14.55 years of work experience (SD = 4.80). Physicians reported to participate in M = 4.36 (SD = 1.71) and nurses in M = 5.1 (SD = 0.51) ward rounds per week, respectively.Participants were chosen based on (i) the amount of their clinical experience with a minimum of four years to possess a realistic view of typical and unusual rounds and (ii) their function as ward physicians or a comparable assigned responsibility for nurses . The sample comprised 14 physicians having After piloting and adjusting the interview schedule accordingly, interviews were performed using the semi-structured interview schedule  to identify general domains of competences from the experts’ point of view avoiding a potential influence of the interview questions.The second part referred to more structured questions regarding the ward round framework and to specific ward round competences (interview schedule parts i and iii).N > 7) of participants, from both professions, mentioned it.For the development of a typical EPA structure  the gainThe first research question put an emphasis on the identification of domains of competences indicated in prior research. We identified 12 domains of competences in the literature that were frequently linked to internal medicine ward rounds  and communication with patients’ relatives (15 %) as relevant ward round competences.Analysis further revealed a general ward round structure that consists of preparation (62 %), consultation of patients (100 %) and debriefing (38 %). 93 % of the physicians and 92 % of the nurses stressed the importance of regular participation of nurses. However 79 % of the physicians and 75 % of the nurses claimed that this is not possible in their daily routine.Building on the competences that were identified in the interview study, we realized the EPA “Conducting an internal medicine ward round”. Each competence was subdivided into several sub-competences and observable tasks, mentioned by the interviewees, were added. In case of substantial overlaps in the domains of competences, these were regrouped after discussion in the research group and consultation of literature. The resulting EPA comprehends nine essential competences which were sub-divided into 18 sub-competences and 62 observable tasks  was spread across various competences. It was thus not regarded separately but included in collaborative clinical reasoning, leadership skills, organization skills, empathy, professionalism, self-management, management of difficult situations and faults, and teaching abilities.The sub-competences of clinical skills and patient-management were also assigned to overlapping domains of competences. Error management was combined with management of difficult situations.Observation but no execution, even with direct supervision.Execution with direct, proactive supervision.Execution with reactive supervision, i.e., on request and quickly available.Supervision at a distance and/or post hoc.Supervision provided by the trainee to more junior colleagues.To ensure the typical link of EPAs to an established competence framework in a second step CanMEDS roles were assigned to each domain of competence to facilitate the identification in which role a trainee may need further training. The Level of supervision  were useWith this study we are able to give a detailed picture of what constitutes ward rounds in internal medicine. We found ward rounds to be a complex task and could contribute to illustrating ward rounds in a detailed manner.The review of literature showed a broad spectrum of competences relevant for conducting an internal medicine ward round. Especially collaborative clinical reasoning, communication with patient and in the team, organization and teaching abilities were named in the majority of the included articles. However, there was a lack of a structured interprofessional approach to ward rounds.In a large extent, the competences identified in this study correspond to aspects found in literature: the role of communication as key competence could be clarified once more. It was not only described in the direct physician-patient contact, but was proven to be strongly attached to all other ward round competences.Again, in line with prior research, collaborative clinical reasoning and organization skills were regarded as particularly important , 25, 26.Further, it could be shown, that the demands of young German doctors are not necessarily consistent with prior studies. Opposed to recent studies e.g. , 10, 27 Above this, our results indicate that education during ward rounds is perceived less important than expected. Even though the experts found teaching a relevant technical skills and communication as well as patient management important, they described patient care as the key goal of ward rounds. Similarly to nurses, students were reported to be irregular participants during ward rounds, which may explain our results. We however understand ward rounds as rich educational encounter not only for students but also for physicians . Ward roBuilt upon the identified ward round competences and observable tasks we propose a description of an EPA “Conducting an internal medicine ward round”. It can be used to prepare medical students and physicians for the affordances of their first day of professional work on an internal medicine ward. Nine competences, 18 sub-competences and 62 belonging observable tasks could be described, which can be used as a guideline for young doctors.Due to methodology, the sample size was comparably small for nationally and internationally generalizable results. However, we observed a clear saturation effect and propose similarity for other German areas and other international countries with similar health systems. Our study shows that the EPA approach is feasible to picture complex situations like ward rounds going beyond clearly defined tasks with a consistent structure and clear responsibilities. Besides, the emerged EPA is founded on a sound empirical basis exceeding prior approaches that specified EPA through small group discussions. While reliability and internal validity of data were ensured by using coding scheme and the insurance of a satisfying intercoder reliability, external validity needs to be examined to allow for transferability of data to other hospitals in other regions.The EPA emerged from an interview study with expert physicians and nurses representing the broad field of internal medicine and hospital characteristics. Thus, it maps the perspectives from both professions regarding relevant competences and belonging tasks that a physician should possess and fulfil on his or her first day after graduation. Based on their vast amount of experience, the interviewed physicians and nurses provided a distinguished picture of aspects relevant for conducting ward rounds in internal medicine. Further research is needed to find similarities and differences between different specialisations in medicine (e.g. surgery) and to define core competencies that are needed in all specialities.The suggested EPA provides a framework for integrating relevant skills in both undergraduate and graduate medical education and facilitates the assessment of students’ and physicians’ ward round competences through observable tasks and thus eases decisions about individuals’ readiness for conducting ward rounds in an objective way , 30. MorFor an easier handling in practice, a short version with all domains of competences Table  as well EPA, entrustable professional activity; LoS, level of supervision