Our study aimed to investigate both the clinical implications of late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) and the relation of LGE to clinical findings in patients with Takotsubo cardiomyopathy (TTC).We evaluated 20 consecutive patients  who were admitted to our hospital with the diagnosis of TTC. CMR was performed within 1 week after admission, and follow-up studies were conducted 1.5 and 6 months later.In 8 patients, CMR imaging during the sub-acute phase revealed LGE in the area matched with wall motion impairment. Cardiogenic shock was more frequently observed in patients with LGE than in those without LGE . The patients with LGE needed a longer duration for ECG normalization and recovery of wall motion than did those without LGE . In 5 of these 8 patients, LGE disappeared within 45-180 days  of onset. The patients with LGE remaining in the chronic phase had higher peak creatine kinase levels than did those without LGE .LGE by CMR in the sub-acute phase may be associated with the severity and prolonged recovery to normal of clinical findings in TTC. Takotsubo cardiomyopathy (TTC), also referred to as transient left ventricular apical ballooning or stress cardiomyopathy, was first reported by Sato et al.  in 1990.Late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) can reveal small and focal myocardial abnormalities and can be useful to diagnose various cardiac diseases . It remaThis study was prospectively conducted between April 2006 and November 2009 at Seirei Mikatahara Hospital, Hamamatsu, Japan. The protocol was approved by the local institutional review board, and all patients gave their written informed consent after the nature of the study and procedures had been fully explained. We prospectively enrolled 20 consecutive patients  67-82 years) who were admitted to our hospital with the diagnosis of TTC according to the criteria of the Mayo Clinic . PatientMR images were acquired with the patient in the supine position with a 1.5-T whole-body MR system  with a four-element phased-array cardiac coil for signal reception. The CMR images were gated to the electrocardiographic signal and were obtained during repeated breath-holds. Cine CMR images encompassing the entire left ventricular cycle were acquired on contiguous short-axis imaging planes with a segmented, fast, low-angle shot cine sequence. The CMR parameters included a repetition time of 4.2 milliseconds for each cine frame, echo time of 1.9 milliseconds, flip angle of 45°, reduction factor of 2, bandwidth of 125 kHz, section thickness of 8 mm with a 2-mm gap, field of view of 240 × 320 mm, and a 320 × 200 image matrix. Fifteen minutes after injection of a gadolinium diethylenetriamine pentaacetic acid contrast agent , LGE inversion recovery images were acquired in the same orientation as the cine images using a 2-dimensional inversion-recovery gradient echo pulse sequence. The following imaging parameters were used: repetition time, 6.6 milliseconds; echo time, 3.1 milliseconds; flip angle, 25°; inversion time, 180 to 230 milliseconds; bandwidth, 31.25 kHz; trigger delay time for inversion recovery pulse, 200 milliseconds; section thickness, 10 mm; field of view, 240 × 320 mm; and image matrix, 192 × 256. The scan parameters were the same for all serial CMR.Images were analyzed according to the consensus of two observers who were blinded to patient data and the results of all other examinations. On all short-axis cine slices, the endocardial and epicardial borders were outlined manually on left ventricular end-diastolic and end-systolic images, excluding trabeculae and papillary muscles. The left ventricular ejection fraction was calculated as follows: (end-diastolic volume - end-systolic volume)/end-diastolic volume. For analysis of the LGE inversion recovery images, LGE was defined as an area of high signal intensity that was 2 and 5 standard deviations (SD) or more greater than the signal intensity of nonenhanced myocardium ,24. If dP < 0.05 was considered statistically significant. All analyses were performed with the SPSS 15.0 software package .Continuous variables are expressed as range, median, and IQR. Because of the limited sample size, non-parametric Mann-Whitney U tests were used to test for statistically significant differences in continuous variables between the study groups. Serial LGE-CMR images were compared using Wilcoxon's signed rank test for paired variables. Categorical variables were compared by Fisher's exact tests. Spearman coefficients were used to evaluate correlation between the LGE area ratio and the duration of abnormal electrocardiographic changes or echocardiographic akinesis. All probability values were 2-sided, and a value of Of the 20 patients with TTC, 18 (90%) were women  after onset.Echocardiography during the acute phase revealed akinesia of the mid and/or apical portion of the left ventricle compared with hypercontraction of the basal left ventricle. Left ventricular outflow tract obstruction occurred in 1 patient. Resolution of the initial echocardiographic abnormalities was observed in all patients within 3-37 days  after onset.Coronary angiography was normal in 16 patients, and the remaining 4 patients had only mild coronary atherosclerosis . No patient had angiographic evidence of epicardial spasm. Baseline left ventricular ejection fraction was 31-61% . Left ventricular akinesia on ventriculography affected the left ventricular apex and mid-portions in 11 patients, who were diagnosed as having typical TTC. The left ventricular apex was not affected in the remaining 9 patients, who were diagnosed as having atypical TTC  after onset. The left ventricular ejection fraction at this time was 41-69% . Complete resolution of wall motion abnormalities had occurred in 3 patients . In the remaining 16 patients, wall motion abnormalities had improved but were still demonstrable.CMR imaging revealed LGE during the sub-acute phase in 8 patients when using a threshold of 2 SD; however, none of the patients had evidence of LGE when using a threshold of 5 SD. The area of LGE was well matched with the area of wall motion abnormality . The signal intensity was much lower than that seen in myocardial infarction or myocarditis. LGE appeared as multiple patches that were spread transmurally Figures  and 4.The LGE area ratio in the sub-acute phase was 5-24% . A significant positive correlation was observed between the LGE area ratio in the sub-acute phase and the duration to normalization of both the electrocardiogram  and the echocardiogram . Serial CMR imaging showed complete disappearance of LGE in 5 patients at 45-180 days  after onset .The major findings of this study are as follows: (1) in 8 of 20 patients with TTC, CMR showed LGE in the matched area of wall motion impairment during the sub-acute phase; (2) cardiogenic shock was more frequently observed in the patients with LGE than in those without LGE; (3) the patients with LGE had a longer duration to ECG normalization and recovery of wall motion than did those without LGE; (4) in 5 of the 8 patients, LGE disappeared within 45-180 days  from onset of TTC; and (5) patients with LGE remaining in the chronic phase had higher peak creatine kinase levels than did patients without LGE in the chronic phase.In the present study, we showed that LGE can be present in some cases of TTC. However, the signal intensity found was lower than that usually documented in cases of myocardial infarction or myocarditis. There have been several reports of LGE in TTC so far -22. BecaRolf et al.  found a Eitel et al.  showed tPossible speculations are that severe stress-induced stunning of the apical segments leads to a patchy pattern of myocardial contraction-band necrosis possibly accompanied by a certain amount of transient focal/patchy edema or deposition of extracellular matrix resulting in LGE with low signal intensity. LGE remains in the chronic phase if the amount of contraction-band necrosis is above voxel resolution. Otherwise, LGE in the chronic phase completely normalizes if contraction-band necrosis is not present or is less than voxel resolution.Our study showed that TTC in the sub-acute phase can have LGE with lower signal intensity than that usually documented in cases of myocardial infarction or myocarditis. For differentiation of TTC from similar symptoms of the acute coronary event, CMR can also help to define the relation of the myocardial segments with wall motion abnormality and the supplied epicardial territory. This implies that if specific CMR characteristics prove to be a non-invasive diagnostic sign for TTC, this could potentially obviate the need for an invasive diagnostic procedure.We could also show that the patients with LGE experienced cardiogenic shock more frequently and had a longer duration to ECG normalization and recovery of wall motion than did those without LGE. These results suggest that the existence and extent of LGE in the sub-acute phase may be associated with the severity and prolonged recovery of clinical findings in TTC.This study is limited by its small sample size; thus, further studies will be needed to confirm our findings. Because we did not perform endomyocardial biopsy in this study, we cannot confirm the relation between histological findings and findings of LGE by CMR in the same patient. Although several studies with CMR have shown the presence of myocardial edema observed on T2-weighted imaging , T2 sequIn conclusion, the LGE and gradual decrease in the LGE tissue volume seen in TTC are much different from the CMR findings in myocardial infarction and other cardiomyopathies and may reflect discrete myocardial contraction-band necrosis and transient focal/patchy edema or deposition of extracellular matrix. The presence of LGE cannot rule out TTC. LGE by CMR imaging in the sub-acute phase may be associated with the severity and prolonged recovery to normal of clinical findings in TTC.CMR: cardiovascular magnetic resonance; IQR: interquartile range; LGE: late gadolinium enhancement; SD: standard deviations; TTC: Takotsubo cardiomyopathy.The authors declare that they have no competing interests.YN and AS contributed to decide the conception and design of this work and to draft, write, and revise the manuscript. KK, KM, MS, YT, SN and YW contributed to the analysis and interpretation of the data. HK, HS, HH, and KA contributed to critical revision of the manuscript for important intellectual content. All authors read and approved the final manuscript.


Cardiomyopathies are common cardiac disorders that primarily affect cardiac muscle resulting in cardiac dysfunction and heart failure. Transgenic mouse disease models have been developed to investigate the cellular mechanisms underlying heart failure and sudden cardiac death observed in cardiomyopathy cases and to explore the therapeutic outcomes in experimental animals in vivo. Echocardiography is an essential diagnostic tool for accurate and noninvasive assessment of cardiac structure and function in experimental animals. Our laboratory has been among the first to apply high-frequency research echocardiography on transgenic mice with cardiomyopathies. In this work, we have summarized our and other studies on assessment of systolic and diastolic dysfunction using conventional echocardiography, pulsed Doppler, and tissue Doppler imaging in transgenic mice with various cardiomyopathies. Estimation of embryonic mouse hearts has been performed as well using this high-resolution echocardiography. Some technical considerations in mouse echocardiography have also been discussed. Cardiomyopathies have been considered to represent diseases that primarily affect cardiac muscle. On the ground of their morphology and pathophysiology, cardiomyopathy may be classified into three major types: hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and restrictive cardiomyopathy (RCM). In the past, most cardiomyopathy cases were described as idiopathic cardiomyopathies, that is, etiology is unknown , 2. Now,in vitro assays using reconstituted myofibrils and the clinical studies with the patients carrying the mutant genes, which will undoubtedly improve our understanding of the mechanisms underlying the cardiomyopathies and provide us with clues for the prevention and treatment of the diseases.Clinical studies showed great heterogeneity among the genetic cardiomyopathic patients even when they carry the same mutation –11. The μm at a depth of 5–12 cm [In general, in the case of DCM, heart failure is characterized by systolic dysfunction , whereas HCM and RCM are characterized by diastolic dysfunction  . To eval 5–12 cm . Our labThe conventional echocardiography is applied in our laboratory on experimental mice. In addition, pulsed Doppler and tissue Doppler imaging (TDI) are also used to determine hemodynamics and the myocardial motion. B-mode is a two-dimensional real-time image of the heart, which is used to visualize and quantify the anatomical structures. A four-chamber image including left and right atria and ventricles can be obtained from the B-mode. Usually, the operator first locates the structure by B-mode then changes to other modes to measure the cardiac wall motion or blood flow. M-mode is the temporal image of cardiac wall motion along a single ultrasound beam, which enables the quantification of wall thickness and cavity dimensions as well as the movement of myocardium, valves, and vessel walls. Usually, left ventricular end diastolic dimension (LVEDD) and end systolic dimension (LVESD), interventricular septum (IVS), and posterior wall (PW) thickness are recorded with M-mode. Shortening fraction (SF) is calculated from the M-mode LV dimensions using the equation:where SF is an index of systolic left ventricular function. Pulsed Doppler imaging is primarily used for the quantitative measure of blood flow through valves, arteries, or veins, which provides information of both the direction and the velocity of blood flow. Tissue Doppler provides the quantifiable information of myocardial tissue movement, for example, the movement of valves. The major parameters in pulsed Doppler and tissue Doppler measurements will be described in the following sections.Left ventricular structure and systolic function is most commonly measured by M-mode in a parasternal short axis view at the papillary muscle level. In order to obtain an anatomically correct parasternal short axis view, operators usually start with parasternal long axis view by placing the transducer vertically to the animal body on the left side of its sternum with the “notch” of transducer pointing to the animal head; and then rotating approximately 30–45 degrees counterclockwise. This view depicts the mid-portion and base of the left ventricle, both leaflets of the mitral valve, the aortic valve and aortic root, the left atrium, and the right ventricle. The parasternal short axis view is obtained by rotating the transducer through 90 degrees clockwise base on the long axis view. Then, the transducer is tilted a little to the apex to visualize the papillary muscles. To ensure all the measure is reliable and repeatable, the short axis view at papillary muscle level is required as a criterion for the imaging used in the later M-mode measure. In other words, the left ventricle is sectioned across the middle of papillary muscles and visualized as a completely round view of it. The left ventricular wall motion along the sampling line is recorded and analyzed in M-mode .With M-mode imaging of the left ventricle, investigators are able to directly measure the thickness of left ventricular posterior and anterior walls and the interventricular septum. The increase in the wall thickness indicates ventricular hypertrophy while the decrease might be observed in ventricular dilation. Left ventricular mass can be calculated based on the wall thickness. Left ventricular chamber diameter at end-diastole and end-systole is also able to be directly measured. As mentioned above, FS can be calculated from the M-mode LV dimensions. In addition, ejection fraction (EF) is another useful index of systolic function, which can be calculated as well from the M-mode measurements.Pulsed Doppler imaging has been used as well to assess the blood flow through aorta. The quantitative data of the blood flow peak velocity, velocity time integral, the peak, and mean gradient can be measured or calculated, which provide us with useful information on systolic function of experimental animals . Aortic in vivo without detected changes in diastolic function suggests that cTnT-DE7 primarily reduces contractile function of the cardiac muscle ([We performed echocardiography studies to measure the cardiac function of cTnT-DE7 transgenic mice (6-month-old) that express an abnormal splice-out of the exon 7-encoded segment in the N-terminal variable region of cardiac troponin T in the hearts. No atrial enlargement, ventricular hypertrophy, or dilation was detected in the hearts of 3-months-old cTnT-DE7 mice, indicating a compensated state. However, left ventricular FS and EF were significantly decreased in 6-month-old cTnT-DE7 mice compared to wild-type controls. Furthermore, the left ventricular outflow tract velocity and gradient were both significantly decreased in the transgenic mouse hearts, indicating decreased systolic function. The impaired systolic heart function  muscle  and late (A′) diastolic mitral annulus velocity and the ratio of E′ to A′ are determined. TDI is very useful to distinguish the pseudo-normalization pattern from the normal filling pattern as reported previously .The ratio of early filling transmitral peak velocity (E) over the TDI mitral valve E velocity (E′) has established itself as a reliable guide to elevated pulmonary capillary wedge pressure . PulmonaWe applied both pulsed Doppler and TDI to our studies on transgenic mice (from 2–12 months) suffering from restrictive cardiomyopathy due to cTnI mutation , 23. We Pulsed Doppler imaging has been used to assess the blood flow through coronary artery of mouse hearts . From a in vivo.We measured coronary artery blood flow using echocardiography Doppler system in wild-type and transgenic mice (2-month-old) with diastolic dysfunction. Our results showed that a significant decrease of coronary circulation was observed in transgenic mice suffering from diastolic dysfunction (unpublished data). These data indicate that the increased atrial and ventricular end-diastolic pressure observed in diastolic dysfunction can reduce coronary artery blood flow since the coronary blood supply occurs mostly during the diastole. Hartley et al. also reported that a significant reduction of coronary flow reserve (CFR) was observed using noninvasive 20-MHz Doppler ultrasound in mice with pressure overload cardiac hypertrophy . EchocarAlthough technically challenging, evaluation of the cardiac dimension and function of mouse embryos is an invaluable tool to assess the role of genes in the early development of cardiac function . We haveCautionary tales of mouse echocardiography have been discussed by several reviews , 16, 28.In addition, we find that prewarming ultrasound transmission gel and keeping the experimental platform at 37°C are necessary to maintain the stable mouse body temperature and heart rate during the procedure of echocardiography measurements.Transgenic mice displaying various cardiomyopathies associated with cardiac sarcomeric protein mutations represent a powerful tool for understanding the mechanisms underlying the initiation and the development of the diseases. High- frequency research echocardiography and pulsed Doppler imaging provide us with a noninvasive and reliable method for the assessment of cardiovascular structural and functional changes in cardiomyopathy mouse models and other murine models. The application of fetal mouse imaging using the high-frequency research echocardiography will open a new way for the studies on fetal cardiac physiology and heart development in mouse models.


Left ventricular (LV) ejection fraction, end-diastolic volume and myocardial mass indexes were 66.2 ± 5.8 %, 66.1 ± 6.6 ml/m2, and 61.0 ± 8.9 g/m2, respectively. No patient showed regional wall motion abnormalities and signs of myocarditis. Nine CSS and 8 WG patients demonstrated decreased segmental longitudinal, circumferential or radial εps and myocardial late gadolinium enhancement (LGE)  areas. In CSS and WG subjects with LVLGE lesions the mean LVLGE extent was 2.0 ± 1.6 % and 2.3 ± 1.5 % (p = 0.65), respectively. Segmental εps was decreased longitudinally (−11.8 ± 5.6 %) for subendocardial LGE, radially (13.7 ± 8.7 %) for subepicardial LGE, and circumferentially (−16.6 ± 4.2 %), longitudinally (−13.2 ± 5.5 %) and radially (18.8 ± 8.1 %) for midwall LGE, if compared to longitudinal (−22.7 ± 5.1 %), circumferential (−23.6 ± 5.6 %) and radial (34.2 ± 15.7 %) εps in controls  . Despite clinical remission, normal ECG and TTE, most CSS and WG patients demonstrate decreased segmental εps and non-ischemic LGE lesions without signs of myocarditis.The aim of the study was to evaluate the presence and spectrum of cardiac abnormalities identified by cardiac magnetic resonance (CMR) in subjects in clinical remission of Churg–Strauss syndrome (CSS) and granulomatosis with polyangiitis (Wegener’s) (WG) with normal ECG and transthoracic echocardiography (TTE). Eleven  CSS and 10  WG patients in clinical remission with normal ECG and TTE underwent CMR. Segmental peak-systolic myocardial strain (ε Churg–Strauss syndrome (CSS) and granulomatosis with polyangiitis (Wegener’s) (WG) represent the rare group of antineutrophil cytoplasmic antibodies (ANCA) associated small vessel necrotizing vasculitis, which may affect the heart . AlthougTwenty-one consecutive patients with CSS and WG in clinical remission were enrolled prospectively. CSS and WG was diagnosed according to the American College of Rheumatology criteria , 20. CliTTE was performed using Vivid 7 system  and analyzed off-line by an independent, experienced viewer, unaware of clinical and CMR data.2, TR/TE = 39/1.1 ms, flip angle = 59°). Morphologic images were acquired with T2-weighted short tau inversion recovery (STIR)  and T1-weighted turbo spin echo imaging . T1-weighted imaging was performed before and early after intravenous infusion of 0.1 mmol/kg body weight gadobutrol . Following contrast injection (10 min), late gadolinium-enhancement (LGE) imaging was performed using T1-weighted segmented inversion-recovery pulse sequence .Breath-hold, ECG-gated CMR was performed on 1.5 T scanner  equipped with cardiac phased array coil. Cine and morphologic imaging was performed in LV two-chamber, four-chamber and long-axis apical views as well as in short-axis views encompassing the entire LV and right ventricular (RV) myocardium. Cine imaging was obtained using balanced steady-state free precession gradient echo  by independent observer, blinded to clinical and echocardiographic data using 16 LV and 9 RV segment models .As previously described endocardial and epicardial RV and LV borders were outlined on short-axis images to calculate EF as well as end-diastolic volume (EDV), end-systolic volume (ESV) and myocardial mass, which were indexed to body surface area .By quantitative analysis mean T2 and T1 signal intensity (SI) (pre- and post-contrast) were measured in (a) individual LV segments (b) entire LV myocardium at mid LV level in short axis view and (c) skeletal muscle (erector spinae/lattisimus dorsi) in the same slice, as previously described . T2 myocLGE images were assessed qualitatively for the presence and location of hyperintense lesions in contrast to hypointense viable myocardium. LGE lesions in LV myocardium were defined as transmural, subendocardial (adjacent to endocardium), midwall and subepicardial (adjacent to epicardium) . Based oAccording to Lake Louise Criteria CMR was considered to indicate myocardial inflammation, when ≥2 of following criteria were present: (a) global T2-SI ratio ≥2.0 (b) global EGE ratio ≥4 and (c)≥1 focal non-ischemic LGE lesion .ps) was measured using 16 segment LV model by an independent observer blinded to clinical and other CMR data. If according to consensus of two experienced observers the course of segmental strain curve at systolic phase was considered to be substantially interfered with artifacts the segment was excluded from analysis.Myocardial strain analysis was performed using Diogenes CMR feature tracking software  applied to two-, three- and four-chamber long axis as well as apical, mid and basal short axis cine images. The subendocardial contours were drawn manually at the end-diastolic frame and then automatically propagated throughout the cardiac cycle. The contouring was manually adjusted to delineate endocardium in every segment at each cine frame, if automatic tracking of endocardial border failed. If after contour adjustment the endocardial border was not accurately tracked throughout the entire cardiac cycle, the segment was considered unevaluable. Myocardial strain was measured using feature tracking technique in 4 pixels neighborhood and radial strain was related to automatically detected epicardial border. The segmental longitudinal, circumferential and radial peak systolic strain  with p < 0.05 considered statistically significant.Categorical data are presented as numbers (percentages), while continuous data as mean ± SD or median with interquartile range, where appropriate. The normal distribution was verified using Kolmogorov–Smirnov test. Categorical variables were compared by Fisher’s exact, Chi square or Cochran Q test, while continuous variables by unpaired/paired student 2). All patients had normal 12-lead ECG. None of the patients demonstrated LVEF <50 %, segmental wall motion abnormalities, moderate/severe valve regurgitation/stenosis, increased systolic pulmonary artery pressure, or pericardial effusion on TTE. Comparing patients with WG and CSS, the former had higher ANCA titre at the time of enrollment (20 (12.5–70) versus 0 (0–10); p = 0.002). Similarly, the maximally measured ANCA titre at prior flares was higher in WG than CSS subjects (200 (80–560) versus 0 (0–10); p < 0.001). CRP was similar in both groups at the time of enrollment. Conversely, maximally measured CRP was higher in subjects with WG, than CSS . In CSS the actual and maximally measured blood eosinophilia was 198 ± 128 and 6964 ± 5882 cells/μl (p < 0.001), respectively. Comparing WG patients with and without prior clinical cardiac manifestations the differences in actual (20 (20–20) versus 30 (15–100); p = 0.59) and maximally measured PR3-ANCA titre at prior flare(s) (180 (40–320) versus 200 (40–800), p = 0.68) were insignificant. Similarly, in CSS subjects with and without prior clinical cardiac manifestations the differences in the actual (0 (0–0) versus 0 (0–20), p = 0.24) and maximally measured MPO-ANCA titre at prior flare(s)  did not reach statistical significance.Eleven CSS patients  and 10 WG patients  were enrolled . LV and RV LGE lesions were found in 17 and 7 patients, with the mean number of involved segments of 2.3 ± 2.0 and 0.7 ± 1.2, respectively , respectively. Six LGE lesions were classified as subendocardial, 10 as midwall and 8 as subepicardial. In CSS and WG subjects LGE lesions were found both in the posterior LV portion  and in the interventricular septum .LVEF, RVEF, LVEDV index and RVEDV index were 66.2 ± 5.8 %, 61.4 ± 5.7 %, 66.1 ± 6.6 ml/mp = NS). In CSS patients the extent and volume of LVLGE lesions did not correlate with the maximum level of blood eosinophilia at prior flare(s) . According to Lake Louise Criteria, no patient demonstrated evidence of myocardial inflammation. Four patients had localized pericardial effusion  and six had abnormal localized pericardial thickening.The extent and volume of LVLGE lesions did not correlate with measured at prior flare(s) maximum level of CRP, ANCA titre, white blood cell count, cumulative DEI and disease duration , circumferentially in 31(9 %), and radially in 43(13 %) LV segments. The mean intra- and interobserver bias for segmental longitudinal εps was 0.02 ± 2.01 and −0.08 ± 2.27 %, for circumferential −0.06 ± 2.34 and −0.20 ± 2.81 %, and for radial 0.07 ± 2.97 and −0.16 ± 3.38 %, respectively , −23.6 ± 5.6 % , and 34.2 ± 15.7 % , respectively. Of those healthy individuals four subjects showed one LV segment with decreased εps . None of the control group demonstrated decline in εps in ≥2 LV segments. Nine CSS and 8 WG subjects (p > 0.99) demonstrated decreased εps ≥2 LV segments and were considered as having reduced segmental εps. In patients with CSS and WG decline in at least one of longitudinal, circumferential and radial εps was found in 66 and 70 LV segments, respectively (p = 0.29). Longitudinal, circumferential and radial εps was decreased in 49, 12 and 18 LV segments (p < 0.001) in CSS patients, and in 32, 24 and 29 (p = 0.48) LV segments in WG patients, respectively. The mean segmental longitudinal εps in WG and CSS subjects was lower than in controls (both p < 0.01) (Table ps (b) segments with midwall LGE lesions showed decreased longitudinal, circumferential and radial εps, while (c) segments with subepicardial LGE areas had decreased radial, but normal longitudinal and circumferential εps  both in the posterior LV portion and interventricular septum , 14, 15.n values .Prior studies have demonstrated variable prevalence and extent of LGE myocardial lesions in WG and CSS. These discrepancies may be attributed to a different clinical profile of studied groups and/or different imaging protocols. Wassmuth et al. . showed ps by TTE, what might elucidate its role to depict early cardiac involvement on a segmental basis and determine the potential superiority of CMR technique. Fourth, an assessment of myocardial velocity, displacement and strain rate, which is available using Diogenes CMR feature tracking software, was not performed. Fifth, myocardial perfusion abnormalities were not evaluated using CMR. The prior studies and case reports have shown that first-pass perfusion might detect subendocardial perfusion abnormalities in CSS and WG subjects who present clinical cardiac manifestation and/or active disease. However, the value of first-pass perfusion CMR technique to detect myocardial involvement in subjects with inactive CSS or WG, normal ECG and TTE has not been determined [First, the study cohort is small and these results should be confirmed in a larger patient cohort. Second, because of the relative contraindication to CMR, patients with low creatinine clearance were excluded and the results may not be applicable to a broader population of CSS and WG patients. Third, we have not assessed εtermined –18. Finaps as well as nonischemic LGE lesions with patchy distribution in all myocardial layers. These lesions are not accompanied by signs of myocarditis and are not reflected by abnormalities during routine ECG and TTE assessment. In WG and CSS CMR may be the most sensitive, non-invasive diagnostic technique to detect cardiac involvement and feature tracking cine-sequence based CMR strain analysis allows for early detection of myocardial contractile impairments, which may correspond with the spatial distribution of LGE lesions.Despite clinical remission, normal ECG and TTE, the heart is frequently involved in WG and CSS. Most patients demonstrate decreased segmental longitudinal, circumferential and radial ε


To predict the type and extent of CMR artifacts caused by commonly used pediatric trans-catheter devices at 1.5 T and 3 T as an aid to clinical planning and patient screening.0direction. The effects of field strength, sequence type, orientation, flip angle and phase encode direction were tested. Clinical CMR images in 3 patients with various indwelling devices were reviewed for correlation with the in-vitro findings.Eleven commonly used interventional, catheter-based devices including stents, septal occluders, vascular plugs and embolization coils made from either stainless steel or nitinol were evaluated ex-vivo at both 1.5T and 3T. Pulse sequences and protocols commonly used for cardiovascular magnetic resonance (CMR) were evaluated, including 3D high-resolution MR angiography (MRA), time-resolved MRA, 2D balanced-SSFP cine and 2D phase-contrast gradient echo imaging (GRE). We defined the signal void amplification factor (F) as the ratio of signal void dimension to true device dimension. F1 and F2 were measured in the long axis and short axes respectively of the device. We defined F3 as the maximum extent of the off-resonance dark band artifact on SSFP measured in the BF1 and F2 were higher (p<0.05) at 3T than at 1.5T for all sequences except 3D-MRA. Stainless steel devices produced greater off-resonance artifact on SSFP compared to nitinol devices (p<0.05). Artifacts were most severe with the stainless steel Flipper detachable embolization coil , with F1 and F2 10 times greater than with stainless steel stents. The orientation of stents changed the size of off-resonance artifacts by up to two fold. Sequence type did influence the size of signal void or off-resonance artifact (p<0.05). Varying the flip angle and phase encode direction did not affect image artifact.Stainless steel embolization coils render large zones of anatomy uninterpretable, consistent with predictions based on ex-vivo testing. Most other commonly used devices produce only mild artifact ex-vivo and are compatible with diagnostic quality in-vivo studies. Knowledge of ex-vivo device behavior can help predict the technical success or failure of CMR scans and may preempt the performance of costly, futile studies. Trans-catheter procedures in children with congenital heart disease have become a mainstay of therapy for many lesions. These procedures involve the placement of stents, vascular occluders, embolization devices and many other implantable devices. Serial follow up imaging is often performed with cardiovascular magnetic resonance (CMR) to assess the integrity of devices, the patency of blood vessels and stents, and the status of cardiac anatomy and function.CMR is particularly well suited to patients with congenital heart disease because of the quality of modern imaging, the lack of ionizing radiation, freedom from contrast nephrotoxicity and the likelihood of multiple follow up studies.CMR and magnetic resonance angiography (MRA) have become the gold standard for imaging many subgroups of congenital heart disease patients, e.g. assessing right ventricular and pulmonary vascular status in treated Tetralogy of Fallot (ToF) patients. However, MR signal loss and off-resonance artifacts from some interventional devices can severely disrupt the signal pattern and render images non-diagnostic. Currently, cardiologists and radiologists are often uncertain how much artifact any given device will create before actually performing the study. Ideally one could make an informed decision about whether or not a study should be undertaken, particularly if anesthesia is required. Moreover, whereas imaging at 3T has potential advantages over 1.5T due to enhanced signal to noise ratio (SNR) , metal aTo our knowledge there have been no published reports on the type and extent of MR image artifact caused by pediatric interventional devices.The goal of our study was to define, by ex-vivo phantom experiments, the influence of magnetic field strength, pulse sequence type, device orientation, flip angle and voxel size on the production of image artifacts from commonly used pediatric, cardiovascular interventional devices.Eleven devices, detailed in Table The experiments were conducted at 3T and at 1.5T. The 3T system was a 32 channel whole body scanner  with the following specifications: gradient strength 40 mT/m, slew rate 200 mT/m/ms, bore diameter 60 cm. The 1.5T system was a 32 channel whole body scanner , with the following specifications: gradient strength 45 mT/m, slew rate 200 mT/m/ms, bore diameter 60 cm. Both scanners were outfitted with similar phased array surface coils and spine coils and operated at the same software level.Imaging was performed with sequences routinely employed for cardiovascular imaging at our institution, including: 2D balanced-Steady State Free Precession (SSFP) for cardiac cine imaging and 2D-flow encoded Gradient Echo for phase-contrast flow measurements, high-resolution, spoiled 3D Gradient Echo (GRE) for contrast enhanced MRA and spoiled 3D GRE with view-sharing for time-resolved contrast enhanced MRA (TWIST).Sequence parameters are summarized in Table Signal voids are expected in GRE sequences because the metallic devices distort the local magnetic field and cause intra-voxel dephasing. Additionally the SSFP sequence is sensitive to off-resonance effects, and banding artifacts are expected to occur due to the deformation of the magnetic field around the devices.The effect of varying the orientation of the stents relative to the B0axis was investigated at 1.5T and 3T. For orientation 1, the acrylic board to which the stents were attached was placed in the scanner with the long axis parallel to B0. In orientation 2, the acrylic board was rotated 90 degrees clockwise and the scans were repeated. For analysis purposes, in orientation 1 the ratio of F3 to true long axis length was derived, for orientation 2 the ratio of F3 to true short axis length was derived.3D-GRE high-resolution MRA sequences were performed at 1.5T with three flip angles: 15 degrees, 30 degrees and 45 degrees.Two directions for phase encoding were tested for each sequence at 1.5T. The size of the F1 and F2 were measured in direction 1 (head-foot direction), and direction 2 (left-right direction).F1, F2 and F3 were compared for the devices composed of stainless steel and nitinol at 1.5T and 3T to investigate the effect of device composition.All six stents  was defined as the ratio of signal void dimension to true device dimension.2. F1 and F2 were measured in the long axis and short axes respective to the device.3. F3 was defined as the maximum dimension of the off-resonance band artifact on SSFP (measured in the B0 direction).Average and standard deviation values were calculated for F1, F2 and F3. The one way ANOVA test was used to compare F1 values between the four pulse sequences at 1.5T and 3T. A paired samples t-test was used to determine significant differences between 1.5T and 3T for F1, F2 and F3 values. An independent samples t-test was used to determine significant difference between stainless steel and nitinol composition.The CMR studies of three patients with congenital heart disease treated by coil embolization (2 patients) or an Amplatzer occluder device were reviewed, for correlation with the ex-vivo findings of the same devices.The Flipper detachable embolization coil  and 3T .At 1.5T, rotation of the acrylic board from orientation 1  to orientation 2 (long axis of stent perpendicular to B0) resulted in an increase in off resonance artifact by factor of 1.3 - 2.5 for stents 1,2,4,5,6. At 3T, rotation of the acrylic board resulted in an increase in off resonance artifact by a factor of 0.8-1.7 for stents 1,2,4,5,6. Stent 3 demonstrated an increase in off resonance artifact by a factor of 3 from orientation 1 to orientation 2 at 1.5T and 3T.There was no significant difference (p>0.05) in F1 and F2 values for different flip angles of 15 degrees,30 degrees and 45 degrees F1 and F2 .There was no significant difference between phase encode direction 1 and direction 2 for any of the four tested sequences  and 3T . No significant difference (p> 0.05) was found in F1 and F2 for stainless steel and nitinol stents: 1.5T  and 3T .In our study, the stainless steel Flipper detachable embolization coil  caused significant disruption to images. The majority of other transcatheter devices did not cause significant signal void, with minimal signal disruption beyond the immediate vicinity of the device, regardless of field strength or pulse sequence type. We recommend careful consideration of whether an MR study should be performed in a child with such a coil in place, if the anatomy of interest is within 5 cm of this device.The results of our study suggest the strength of the magnetic field, device composition, sequence type and orientation of the device in B0 have the largest impact on the amplification factor of implanted devices in an MR environment. The flip angle and direction of the phase encode direction do not affect amplification. Certain devices, such as the stainless steel embolization coil cause significant disruption of images, and patients with such devices should undergo careful consideration before scans are performed. The prior knowledge of artifact size and proximity to an anatomical structure of interest may influence the decision to perform a CMR study, or allow the study to be planned with optimal parameters to minimize artifacts. In children who often require general anesthesia for an, the risks of anesthesia may not outweigh the benefit of the scan if there is considerable image disruption. This knowledge could also influence the choice of device by the interventional pediatric cardiologist.Larger artifact size was encountered at 3T than 1.5T. Imaging at higher magnetic field strength results in stronger susceptibility artifacts ,5. In a Our results found stainless steel devices to produce more artifact than nitinol devices. The 316 low carbon alloy of stainless steel is austenitic and non-magnetic , howeverWhile the ferromagnetic properties of a device correlate with the expected size of image artifacts, non-ferromagnetic devices can also produce significant image artifacts. This is thought to be due to a reduction of radiofrequency amplitude near the device which depends on its shape and is most pronounced near edges and points of the metallic surface .et al, also found largest artifact is observed when the position of stents was perpendicular to B0, smallest artifact occurs when stent is parallel to B0 [In our study, increased artifact was found when stents were placed with the long axis perpendicular to B0. Hug el to B0 . Paralleel to B0 .Our findings suggest a significant difference in artifact size between difference imaging sequences. In another study of 15 coronary artery stents deployed in 15 healthy swine coronary arteries, vessel visualization and image artifact was compared between a 3D cartesian gradient echo sequence, a 3D spiral gradient echo sequence and a cardiac triggered 3D SSFP sequence . With thet al investigated the optimal flip angle at 1.5T for minimal reduction of signal inside 3 stents made from: 316L stainless steel, nitinol and ABI alloy. Highest signal for nitinol and stainless steel was found at flip angle of 90 degrees, and for ABI alloy was 270 degrees [An increase of the flip angle results in higher radiofrequency power of the excitation pulse and improved lumen visualization ,20. Holt degrees . Our resWe did not find a significant difference in the size of artifacts encountered between changing the phase encode directions for any sequence. Acquiring the scan with the read direction along static magnetic field results in better lumen visualization . The oriThe Flipper Detachable Embolization Coil  was found by visual assessment to have distinctly different magnetic properties to the other devices. Cook Medical has labeled stainless steel embolization coils as MR conditional. MR conditional is described as an item has been demonstrated to pose no known hazards in a specified MR environment with specified conditions of use . The newOne major limitation to our study was that we were not able to test every parameter for every sequence at both field strengths. Additionally, the range of flip angles we tested was relatively narrow compared to other authors, which led to different conclusions to other published work. However, our study was designed to reflect typical clinical imaging scenarios, rather than to explore a wide extent of parameter space. Secondly, our study did not include any in vivo data, and we did not place the devices in artificial tubes to mimic blood vessels. However we are able to demonstrate the appearance of signal void by various devices seen in patients at our institution Figures ,12,13,14In conclusion, careful consideration of prior implanted devices in a patient is necessary before CMR is performed. Selection of magnetic field strength, sequence type, device composition and orientation in the magnetic field will minimize image disruption from these devices. Stainless steel embolization devices will produce large artifact, whereas stainless steel stents cause minimal disruption.The authors have no financial conflicts of interest to report.Guarantor of integrity of entire study (PF), Study concepts (PF), Study design (SK), Definition of intellectual content (DL), Literature research (SK), Clinical studies (PF), Experimental studies (SR), Data acquisition (SK/SR), Data analysis (SK), Statistical analysis (SK and SR), Manuscript preparation (SK), Manuscript editing (DL and PF), Manuscript review . All authors read and approved the final manuscript.


The Duchenne muscular dystrophy (DMD) associated cardiac disease results in significant morbidity and mortality usually resulting in death by the second to third decade of life. End-stage cardiac pathology consists of alternating areas of myocyte hypertrophy, atrophy and fibrosis manifesting as late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) evaluation. There has been considerable interest in detecting the presence of LGE, and previous studies have associated LGE with global ventricular dysfunction as assessed by ejection fraction (EF). However, given the genetic origins and underlying pathogenesis of DMD-associated cardiac disease, we hypothesized that LGE is prevalent in patients without overt disease.CMR studies performed between June 2006 and June 2011 were analyzed. Standard imaging sequences included cine images and LGE sequence of the left ventricle. Global ventricular function was assessed using QMASS® and LGE was assess qualitatively and reported as negative or positive. The presence of LGE was compared to age and EF. Statistical analysis was performed using SAS  and reported as percentages and odds ratios (OR) with confidence interval (CI).We analyzed 247 CMR studies in individual DMD patients and compared the presence of LGE to age and EF Figure . The preThis large series shows a high prevalence of LGE in DMD patients. LGE is strongly associated with age and global dysfunction. Thus it is most common in older patients with reduced EF. However, it is also detected in young DMD patients with normal EF. LGE may be a useful biomarker for detection of progression of DMD-associated cardiac disease. As such, it may have important implications to clinical care and research.None.


Physicians caring for the critically ill are now expected to acquire competence in echocardiography. It has become an indispensable diagnostic and monitoring tool in acute care settings where it is generally accepted to have therapeutic impact. There are a number of indications for a critical care echocardiographic study, and the most important queries include those pertaining left and right ventricular function and filling status. Focused examinations are increasing in popularity and provide a means for systematic study, and can be easily learned and practiced by novices. This paper addresses the indications, therapeutic impact, and some of the most common questions that can be answered using echocardiography the in critically ill patient. Echocardiography is now considered an indispensable tool for diagnosis and haemodynamic monitoring in critically ill patients. Indications for performing echocardiography in the ICU have expanded and it is now considered a requirement for critical care physicians to acquire competence in this mode of monitoring. Reflecting this are the numerous competency guidelines published in recent years –4.Potential advantages and disadvantages of echocardiography compared to invasive haemodynamic monitoring  in the critically ill are listed in This paper is not intended to be a comprehensive review of echocardiographic techniques. It does not include a review of left ventricular diastolic function, or lung ultrasound, a rapidly growing and increasingly important imaging modality .Instead it addresses the indications, therapeutic impact, and some of the most common questions that can be answered using echocardiography in critically ill patients.There are no randomized trials/metaanalyses regarding the impact of echocardiography on critically ill patients. A number of studies attest to the usefulness of echocardiography in the intensive care unit –9. For eEchocardiography in critical care settings may be indicated for (1) diagnostic purposes, (2) guiding interventions and therapy, and (3) monitoring and followup.The most important indications within the critical care context include diagnosis of major valvulopathies, major structural abnormalities , endocarditis, pericardial effusion, and tamponade. It is also indicated for the evaluation of chest pain and unexplained shortness of breath, suspected pulmonary embolism, and respiratory failure of uncertain aetiology. It is used for the evaluation of shock or haemodynamic instability, where the determination of filling status and left and right ventricular function are key questions. In terms of monitoring, echocardiography may be used to assess responses to fluid and vasoactive therapies.In the latest publication of the American College of Cardiology Appropriate Use Taskforce, appropriate use criteria were established for the use of TTE for cardiovascular evaluation in the acute care setting  Table 2Table 2. In recent years, several focused echocardiography protocols have been introduced . These sThere are several ways of approaching the echocardiographic examination of the critically ill. While several focused protocols exist, two such protocols, RACE and FATE, have gained widespread popularity and are described here.This author finds RACE (rapid assessment by cardiac echo) useful for the initial echocardiographic evaluation of the unstable critically ill patient. This method ensures that the examination is conducted systematically, and stresses that findings be put within the context of the patient's clinical status. Two modes  and 5 views  are used to answer the following four questions.What is the left ventricular function?What is the right ventricular function?Is there any evidence of pericardial effusion and cardiac tamponade?What is the fluid status? The authors of RACE also stress that it is not a full TTE study, does not include Doppler measurements, and that a full transthoracic echocardiographic assessment should be requested if considered clinically necessary. Nevertheless, RACE is a good initial approach to the evaluation of the haemodynamically unstable patient and provides a skill set that can be easily learned by novices.Another focused echocardiographic protocol is FATE (focused assessed transthoracic echocardiography) . The purThis paper will not include details of a full echocardiographic examination and the reader is referred instead to the numerous publications available with special focus areas –19. HoweAssessment of global LV contractility may be quickly obtained by “eyeballing” from the parasternal long- and short-axis, apical 2- and 4-chamber and subcostal views , 18. ExpTwo other modes of imaging that are relatively easy to obtain for the assessment of LV function are the atrioventricular plane displacement (AVPD) and systolic tissue Doppler velocities (sTD)  20–22].–22.20–22In addition to contractility, assessments of chamber size and LV wall thickness are made. These serve as an indication of fluid status, cardiomyopathies, and the presence of nonviable myocardium. Left atrial size is evaluated as an enlarged LA may indicate significant mitral and aortic valve disease, intra-atrial shunting and atrial fibrillation, all of which may contribute or cause haemodynamic instability. Further, LA size may provide an indication of elevated LV filling pressures.Finally, the aortic and mitral valves are made to complete the examination of left ventricular function. Measurement of stenotic areas and regurgitant volumes are difficult and highly variable in the critically ill patients with varying volume status and mechanical ventilation. For this reason, echocardiographic evaluation of the critically ill should identify major pathology, but quantification of such should be made by experienced operators only, and taking into consideration the clinical context. A focused critical care echocardiographic examination should be able to identify, but not quantify, major valvulopathies that may contribute to or explain haemodynamic instability, such as significant aortic stenosis and mitral regurgitation, using 2D and colour Doppler imaging.Assessment of right ventricular function is of particular interest in critical care due to the effects of fluid loading and mechanical ventilation on the right heart. Due to ventricular interdependence , impaireRV function is assessed initially from its size, wall thickness, and contractility. Comprehensive guidelines for the echocardiographic assessment of the right heart are given in a recent report of the American Society of Echocardiography . For theThe right atrium (RA) is examined for size and abnormal masses. A dilated RA may be indicative of fluid overload, interatrial shunts, tricuspid disease, and increased pulmonary pressures. Atrial fibrillation and mechanical ventilation may also cause a dilated RA. Finally the tricuspid and pulmonary valves are examined for abnormalities.Measurement of the tricuspid regurgitant velocity is a relatively simple procedure and is used for the estimation of pulmonary arterial systolic pressure using the simplified Bernoulli equation , 14. TypEstimation of preload by assessment of ventricular volumes is one of the most challenging areas in critical care echocardiography. Firstly, altering compliance complicates the pressure-volume relationship . Added tThe right ventricular dimensions are normally smaller than those of the LV. While RV dilatation may indicate volume overload, it is not specific for this. RV dilatation may occur for example due to mechanical ventilated with high PEEP. The RA size may be increased and an enlarged RA with bowing of the intra-atrial septum towards the left is indicative of elevated right atrial pressure. The triad of a “kissing” LV, small LV and RV size, along with a normal or small RA is strongly suggestive of hypovolaemia.DI). This is defined asA method for assessing fluid responsiveness in patients with controlled mechanical ventilation, that is, not on assist modes, is the distensibility index of the inferior vena cava  , 3426, 3Echocardiography is the tool of choice for evaluating the pericardial sac and the presence of tamponade. The diagnosis of a pericardial effusion is made from the observation of an echo-free space between the parietal and visceral pericardium seen from the parasternal, apical, and/or subcostal views.The presence of haemodynamically significant pericardial fluid is typically assessed by examination of the RA and RV. RA collapse during early systole and RV collapse during early diastole indicate that intrapericardial pressure exceeds right heart pressures. These findings, together with a dilated IVC are signs of a haemodynamically significant tamponade .Echocardiography is important development in critical care. However, as with any diagnostic and monitoring tool, echocardiography is subject to errors in interpretation, and there is a range of individual responses for any given study. No single tool is complete; however, echo provides some distinct advantages compared to invasive monitoring, not least of which are noninvasiveness and the ability to conduct a direct anatomic evaluation of the heart and its component parts in real time.There are a number of focused approaches designed to facilitate the conduct of a systematic echocardiographic study. A number of guidelines have been issued for training and competency, which are designed to enforce standards and define core skill sets required for examination of the critically ill patient. The most important of these have been addressed in this review.


Left atrial (LA) size and function are often regarded as a reflection of left ventricular (LV) hemodynamics.Purpose:In this study we investigated the hemodynamic correlates of contrast transit time within the left atrium (LA) in patients with LV systolic dysfunction by cardiac magnetic resonance imaging (CMR).Ten subjects undergoing clinically indicated right and left heart catheterization and 48 subjects undergoing noninvasive evaluation were prospectively enrolled and brain natriuretic peptide (BNP) and N-terminal proBNP (NT proBNP) obtained prior to CMR examination. CMR was performed within 5 hrs of invasive hemodynamic assessment. Dynamic MR imaging was acquired in sagittal and coronal planes covering the LA using a saturation recovery SSFP sequence with bolus injection of 0.01 mmol/kg gadopentetate. Mean transit time was measured in the LA and normalized to heart rate. LV systolic dysfunction was defined as LV ejection fraction (LVEF) < 50%. Noninvasive cohort also underwent echocardiography within 2 hours of CMR. Tissue Doppler was used to determine mitral E/e’ ratio.Normalized mean LA transit time (nLATT) by CMR correlated strongly with LV early diastolic pressure , end diastolic pressure (LVEDP)  and mean diastolic pressure  in the invasive cohort. In the noninvasive cohort nLATT was significantly prolonged in patients with LV systolic dysfunction (N=39) 10.1±3.0 heart beats vs 6.6±0.7 heart beats in normal controls (N=9) (p<0.001). In patients with LV systolic dysfunction average LVEF was 37±9% and the NYHA functional class1.8±0.9. Using a linear regression equation derived from the invasive cohort LVEDP was estimated in the noninvasive cohort which was divided into 3 subgroups: ≤ 10 mmHg, 11-15 mmHg and ≥ 16 mmHg. There were graded increases from low to high LVEDP subgroups in echocardiographic mitral medial E/e’ ratio: 9±3, 14±7 and 18±13 (p=0.005); BNP: 53±41 pg/ml, 286±433 pg/ml, 496±475 pg/ml (p<0.001) and NT proBNP: 171±268 pg/ml, 712±948 pg/ml, 1249±1137 pg/ml (p<0.001), demonstrating the concordance of nLATT with established noninvasive indices of hemodynamic status.nLATT by dynamic MRI may be a valuable non-invasive marker of LV filling pressure in patients with LV systolic dysfunction.


MR diffusion-weighted imaging is an important application for oedema detection in various tissues. Evaluation of the area at risk in reperfused acute myocardial infarction (AMI) is currently performed with STIR T2-weighted and LGE sequences.The aim of the study was to find practical application for a new diffusion-weighted sequences in evaluation myocardial oedema and compare it with routinely used STIR-T2 techniques.In preliminary study myocardial oedema in 15 patients  with STEMI within 2-4 days were evaluated .The CMR examination was performed on a 1,5 T scanner  using a 8-channel phased-array coil. The parameters of the diffusion-weighted EPI sequence (DWI) were as follows: slice thickness 10mm, repetition time (depending on patient breath cycle) 3-4s, echo time 78ms, bandwidth 1,736 Hz/Px. The DW sequence was ECG-gated and synchronized to the respiratory cycle using PACE technique. Each slice was acquired with b = 50 s/mm2, 400s/mm2 and 800 s/mm2 with three perpendicular directions of the diffusion gradient. DW, STIR T2-weighted and LGE images were obtained in 2-chamber, 4-chamber or short-axis planes. Images were analysed quantitatively, contrast to noise ratio (CNR) of high signal (oedema) to healthy myocardium (CNR1) and high signal to blood (CNR2) were calculated. For statistical analysis a non parametric Wilcoxon test with significance level of p<0,05 was used.The CNR were significantly higher on DWI than on STIR T2-weighted images: CNR1 and CNR2 .Our study confirms DW EPI is feasible sequence for myocardial oedema detection with even better contrast to noise ratio than standard STIR T2 sequences.


Reduced SERCA2a content and blunted Ca2+ reuptake are frequently observed in failing hearts and evidence implicates poor cardiac Ca2+ handling in the progression of heart failure. To gain insight into mechanism we investigated a novel genetic mouse model of inducible severe and progressive SERCA2 deficiency . These mice eventually die from overt heart failure 7-10 weeks after knockout but as yet there have been no reports on intrinsic mechanical performance at the isolated whole heart organ level. Thus we studied whole-organ ex vivo function of hearts isolated from SERCA2 KO mice at one and four weeks post-knockout in adult animals. We found that isolated KO heart function was only modestly impaired one week post-knockout, when SERCA2a protein was 32% of normal. At four weeks post-knockout, function was severely impaired with near non-detectable levels of SERCA2. During perfusion with 10 mM caffeine, LV developed pressures were similar between 4-week KO and control hearts, and end-diastolic pressures were lower in KO. When hearts were subjected to ischemia-reperfusion injury, recovery was not different between control and KO hearts at either one or four weeks post-knockout. Our findings indicate that ex vivo function of isolated SERCA2 KO hearts is severely impaired long before symptoms appear in vivo, suggesting that physiologically relevant heart function in vivo can be sustained for weeks in the absence of robust SR Ca2+ flux.The cardiac SERCA2 Ca Reuptake of Ca2+ into the sarcoplasmic reticulum (SR), accomplished by the cardiac SR Ca2+ ATPase (SERCA2), plays a major role in cardiac muscle relaxation and also is critical in determining SR Ca2+ load and subsequent systolic Ca2+ release. Defects in Ca2+ handling are clearly associated with cardiac dysfunction and heart failure2+ flux and reduced SERCA2a expression are frequently observed in the failing heart, the exact relationship between these observations is not fully known. It is not clearly established whether loss of SERCA2a is a driving primary cause of severe cardiac dysfunction or whether this is a secondary consequence of the emerging cardiac pathology.Normal heart pump function requires the highly regulated, cyclical release and reuptake of CaSerca2+/− mice, which express approximately 60% of normal SERCA2a protein content, have only mildly impaired functionSerca2 heterozygous mice represent only one state of diminished SERCA2a activity, a more refined approach to study the relationship between SERCA2 expression and heart function in adult mice is necessary. A recently developed model of inducible SERCA2 knockout, the SERCA2 KO mouse, allows for selective disruption of the Serca2 gene in the hearts of adult miceSerca2 gene locus are flanked by loxP sites, thereby allowing selective disruption of Serca2 in adult cardiac myocytes conferred by a tamoxifen-sensitive, cardiac myocyte-expressed MerCreMer transgenein vitro in isolated cardiac myocyte studies, as well as in vivo by survival, echocardiography and invasive micromanometry studiesSerca2 gene disruption, SERCA2a protein is rapidly lost from the heart (t1/2 ∼3 days). Despite the emergence of severe cardiac SERCA2a deficiency within weeks, the SERCA2 KO mice survive for up to 10 weeks post-knockout before finally succumbing to end-stage heart failure and pulmonary congestion2+ transient magnitude, and Ca2+ transient decay ratesin vivo phenotype at these time-points as assessed by echocardiography, however, is surprisingly mild. This suggests that SERCA2 KO mice are capable of compensating, at least temporarily, for the loss of SERCA2 activity for much longer than predicted based on current knowledge of cardiac Ca2+ handling and SR function , and either contained (TG) or did not contain (NTG) the αMHC-MerCreMer+/o transgene. Mice were genotyped as described fl/flSerca2; TG:αMHC-MerCreMer+/o mice efficiently deleted Serca2 in response to tamoxifen and became 0Serca2 (KO) in the heart, while fl/flSerca2; NTG animals retained the floxed Serca2 gene and normal SERCA2 expression (FL controls). FL and KO groups were sacrificed by sodium pentobarbital injection (100 mg/kg i.p.) and exsanguination at 1 and 4 weeks post-tamoxifen injection and their hearts were removed for ex vivo functional analysis . Mice were housed on a 12-12 hour light-dark cycle and provided rodent chow and tap water analysis . All mic4, 1.2 KH2PO4, 0.5 NaEDTA, 2.5 CaCl2, 15 Glucose, 25 NaHCO3, 0.5 NaPyruvate). The aorta was trimmed and cannulated, and the heart was mounted on a Langendorff apparatus  and retrogradely perfused with KHB bubbled with 95% O2 / 5% CO2 and maintained near 37 °C with a water jacket. The atria were removed, and a balloon catheter was inserted into the left ventricle (LV) to measure isovolumic LV pressure. An electrode placed at the base of the heart controlled pacing frequency, which was set at 7 Hz (pacing cycle length of 1000/7 = 143 milliseconds) for baseline and equilibration.Mice were anesthetized with sodium pentobarbital (100 mg/kg i.p.) and heparinized (250 IU i.p.). Upon loss of toe pinch reflex, the ribcage was opened and the heart was removed to a dish of ice-cold Krebs-Henseleit solution .g for 2 minutes. Supernatant protein concentration was determined using bicinchroninic acid.After the Langendorff protocol was complete, hearts were removed from the cannula, quickly blotted and weighed, and frozen using liquid nitrogen. Frozen hearts were pulverized in a liquid nitrogen-cooled steel deadblow, resuspended in 750 µl RIPA , briefly sonicated, and centrifuged at 14,000xHeart lysates were diluted to 1 µg/µl with RIPA and Laemmli buffer, and then 20 µg protein per lane was fractionated on 12.5% Tris-Glycine gels (BioRad Criterion) and transferred to PVDF membranes. SERCA2a and Actin were detected by immunoblot  at 1∶1000; Actin, A-2103 (Sigma) at 1∶10,000) using an Odyssey imaging system .t test or two-way analysis of variance with Bonferroni post-test, where appropriate. Significance was set at P < 0.05. Data is presented as mean ± SEM unless SEM was smaller than figure icon.Data was acquired using LabChart 6 software (AD Instruments) and analyzed using Prism 5.02 (GraphPad). Significance was tested by unpaired two-tailed Serca2 FL and Serca2 KO hearts were studied at one and four weeks after tamoxifen injection. Following tamoxifen injection, SERCA2 protein was rapidly lost from the heart  was significantly reduced in KO hearts compared to FL. In addition, times to 50% pressure rise (T50% Rise) and fall (T50% Relaxation or T50R) were significantly increased in KO hearts relative to FL at 1 week post-tamoxifen. In comparison, at four weeks post-tamoxifen, KO hearts had severe systolic and diastolic dysfunction relative to FL. In KO hearts LV developed pressure and maximal and minimal dP/dt were markedly decreased, and end-diastolic pressure (LVEDP) and times to 50% rise and 50% relaxation were significantly increased (P<0.05). Representative traces of LV pressure (Isolated heart contractile parameters at baseline are detailed in pressure .−1/ pacing frequency s−1), thus representing the time interval between the end of one peak and the beginning of the next, was elevated in KO hearts at low pacing frequencies  as pacing frequency increased . At fourquencies . These mFollowing force-frequency response determination, whole hearts were subjected to ischemia-reperfusion (I/R) challenge to test the hypothesis that the magnitude of I/R-mediated LV pressure dysfunction is modulated by progressive SERCA2a deficiency. At one-week, KO hearts had reduced pre-ischemic baseline LVDP compared to FL hearts, however both groups produced similar absolute developed pressures during reperfusion . In cont2+ handling in FL and KO hearts by using caffeine to modulate excitation-contraction coupling. Isolated 4-week FL and KO hearts were perfused with 10 mM caffeine, a ryanodine receptor (RyR) activator, to modulate SR Ca2+ handling and reveal non-SR dependent contractile function. Caffeine perfusion releases SR Ca2+ stores, thus forcing hearts to depend on SR-independent Ca2+ handling pathways for contractility. Representative traces of 4-week FL and KO hearts during caffeine perfusion are shown in In an additional set of experiments, we sought to further evaluate CaSerca2 gene disruption with the goal to interrogate organ level performance in the context of progressive and severe SERCA2a protein depletion. Under standard conditions at one week after Serca2 gene disruption, where cardiac SERCA2a protein content is 32% of control values, isolated whole heart performance is surprisingly near normal. In comparison, under the same standard testing conditions of whole heart function four weeks after Serca2 gene disruption, where cardiac SERCA2a protein is at near non-detectable levels, there are severe deficiencies in both systolic and diastolic LV function at the level of the isolated intact heart. Cardiac stress testing by increasing pacing rates further and dramatically unmasks relaxation performance deficits at early and late time points after gene disruption and establishes the SERCA2a dose-diastolic performance response relationship. Overall these new findings parallel those obtained previously in isolated myocytes from SERCA2a KO micein vivo function where heart morphology and whole behavior appear relatively normal. This later point is in keeping with findings of apparent normal echocardiography assessment, at least in the early weeks after severe SERCA2a depletion in vivoThis study reports new findings of left ventricular whole heart function after targeted +/−Serca2 mice, which constitutively express about 60% of normal SERCA2 protein. Serca2 heterozygous mice have slightly impaired cardiac function, but this does not appear to negatively impact the overall health of these micein vivo pathology. In this way it is possible to perform detailed study of heart function as SERCA2 protein is specifically and progressively lost from the myocardium. In this context, severe SERCA2a deficiency from 32% of control levels down to near zero levels markedly disrupts heart organ function and yet at ∼ 1,000,000 cardiac pump cycles/day the animal can survive for many weeks before overt cardio-respiratory failure ensues.Our results from the inducible SERCA2a knockout mouse are interesting in the context of previous findings in ex vivo heart performance and in vivo function is evidence that KO mice are capable of compensating for the loss of cardiac SERCA2 protein for up to two months before ultimately failing. Along these lines, recent reports on isolated rabbit hearts exposed to the SERCA2 inhibitor, thapsigargin, also show a surprising extended time of whole heart function that too appears to uncouple isolated myocyte SR Ca2+ flux and whole-heart contractilityThe physiological disconnect between the Serca2 disruption that may support heart function in the absence of robust SR Ca2+ flux. For example, there are modest increases in the expression and activity of the L-type Ca2+ channel, the Na+-Ca+ exchanger, and the plasma membrane Ca2+ ATPaseSerca2 KO cardiac performance in vivo is maintained by enhancing trans-sarcolemmal Ca2+ transport while SR Ca2+ handling is reduced. KO myocytes exhibit greater Ca2+ transients than FL when stimulated during caffeine perfusion2+ flux is unlikely to account for preserved systolic function after Serca2 disruption. Systolic performance in FL and KO hearts is nearly identical during caffeine perfusion. End-diastolic pressures are lower in KO hearts during caffeine perfusion, suggesting that increased NCX and PMCA levels found 4 weeks post-KO can help sustain diastolic performance. KO hearts tend to deviate from the programmed stimulation frequency, 7 Hz, soon after the application of caffeine, indicating that this increased dependence on trans-sarcolemmal Ca2+ fluxes can sensitize KO hearts to arrhythmic behavior2+ handling mechanisms of Serca2 KO hearts may contribute to comparatively preserved end-diastolic pressures, but not systolic performance, during caffeine exposure. Increased dependence on Ca2+ current, however, may render KO hearts susceptible to arrhythmias. Additional studies will be required to further specify how KO hearts maintain systolic performance in vivo as SR function is gradually abolished.As of yet the mechanism allowing for this compensation is not clear, although there are several changes shown to occur following Serca2 loss-of-function mutations are functional Serca2+/− heterozygotes, show no sign of cardiac disease or dysfunctionLoss of SERCA2 expression and activity is well documented within a wide variety of cardiac pathologies in human patients. However, in this context it is interesting to note that patients with Darier's disease, which owing to Serca2 KO mice was to assess the relationship between SR function and ischemia-reperfusion injury. Earlier reports of altered SR function using phospholamban deficient mice reported much more severe I/R-mediated heart performance deficits than in controls2+ uptake and load are reduced would have opposite effects and paradoxically could be beneficial in terms of relative LV functional deficits in I/R. In 1-week KO hearts with SERCA2a reduced to 32% of control, mean values for LVDP tended to be higher than controls but this did not reach statistical significance by ANOVA analysis. Thus, although increasing SR Ca2+ load by phospholamban ablation severely impairs recovery from ischemic injuryAnother motivation for studying in vivo cardiac function and survival are currently unclear, identifying the manner in which hearts compensate for severely diminished SR Ca2+ flux could prove highly beneficial to our understanding of the interrelationship between SR Ca2+ derangements and cardiac disease.In conclusion, these findings show that progressive loss of SERCA2 protein from heart following inducible knockout initiates rapid, severe decline in the contractile performance of isolated whole hearts. Although the mechanisms allowing for sustained


Phase-contrast magnetic resonance imaging is a technique that allows for characterization of regional cardiac function and for measuring transmural myocardial velocities in human hearts with high temporal and spatial resolution. The application of this technique  to murine hearts has been very limited so far. The aim of our study was to implement and to optimize tissue phase mapping for a comprehensive assessment of murine transmural wall motion. Baseline values for regional motion patterns in mouse hearts, based on the clinically used American Heart Association's 17-segment model, were established, and a detailed motion analysis of mouse heart for the entire cardiac cycle  is provided. Black-blood contrast was found to be essential to obtain reproducible velocity encoding. Tissue phase mapping of the mouse heart permits the detailed assessment of regional myocardial velocities. While a proof-of-principle application in a murine ischemia–reperfusion model was performed, future studies are warranted to assess its potential for the investigation of systolic and diastolic functions in genetically and surgically manipulated mouse models of human heart disease. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc. Genetically and surgically modified mice have become the animal models of choice for human cardiac disease. Fast, high-resolution, multiframe magnetic resonance imaging (cine-MRI) has been established in recent years as a routine tool in many research laboratories around the world to noninvasively assess global cardiac function –6. Left This article aims to overcome the limitations described above. Specifically, we sought: (A) to investigate the feasibility of a comprehensive assessment of myocardial wall motion in three dimensions analogously to clinical practice at three levels in the heart , using a conventional, commonly available preclinical MR system interfaced to a 9.4-T magnet; (B) to optimize the method with respect to temporal/spatial resolution and scan time; (C) to demonstrate the benefits of black-blood over bright-blood contrast in murine phase-contrast MRI; (D) to establish baseline values for regional motion patterns in mouse hearts, based on the American Heart Association 17-segment model ; (E) to All MR experiments were carried out on a 9.4-T (400 MHz) MR system  comprising a horizontal magnet (bore size = 210 mm), a VNMRS Direct Drive™ console, an actively shielded gradient system , and a quadrature-driven birdcage resonator .n = 22, 23.1 ± 1.8 g) were obtained from a commercial breeder  at least 1 week before the first imaging time point to allow naturalization to new surroundings. The mice were kept under controlled conditions for temperature, humidity, and light, with chow and water available ad libitum. Anesthesia was induced in an anesthetic chamber using 4% isoflurane in 100% oxygen. Animals were then positioned prone on dedicated mouse cradles and maintained at 1.5–2% isoflurane at 2 L/min oxygen flow throughout the MRI experiments. A 0.5-mL Eppendorff tube filled with 1% agarose (spiked with 2 mM Gd-DTPA) was placed next to the chest of the animal to correct background phase errors , the left coronary artery was occluded for 45 min followed by reperfusion as described in Ref.All investigations conformed to Home Office Guidance on the Operation of the Animals (Scientific Procedures) Act, 1986 (HMSO) and to institutional guidelines.2, matrix size = 128 × 128, TE/TR = 2.1/4.6 ms, slice thickness = 1 mm, 15° sinc excitation pulse, number of averages NT = 2, vencin-plane = 6 cm/s, and vencthrough-plane = 8 cm/s. Velocity-encoded/compensated scans were acquired in an interleaved fashion. For each line in k-space, the motion-compensated acquisition was executed for all time frames of one cardiac cycle, followed by the three motion-encoded scans in three successive heartbeats before incrementing the phase-encoding gradient . A saturation module  at the end of each cine-train, which consisted of two 4-mm saturation slices, applied 4.5 mm above and below the imaging slice, followed by a crusher gradient, provided black-blood contrast. The remaining ventricle was covered with conventional bright-blood cine-imaging by turning off the motion-encoding and black-blood modules . All sequences were ECG-triggered and respiratory-gated with steady-state maintenance during respiration [i.e., the sequence continued to run during respiration with the same timing , but no data were acquired, and all internal counters were not incremented—see Ref.The phase-contrast imaging sequence was based on a two-dimensional multiframe gradient echo sequence. Motion-compensating and -encoding gradients were combined with the imaging gradients as reported previously , 17. AftVelocity assessment by means of phase-contrast MRI was validated on a flow phantom with pulsatile flow using an MR-compatible flow-sensor (placed inside the magnet and outside the RF coil) before in vivo application. TPM experiments were conducted at three different flow rates  with venc's of 40, 50, and 60 cm/s, respectively. A trigger signal was derived from the flow curve and used to synchronize the MR experiment.n = 6, 23.6 ± 1.2 g), where a mid-ventricular slice was additionally acquired with identical sequence parameters, but the saturation module at the end of the cine-train turned off. Typically, two more frames were obtained instead in this case. To exclude the inherent variability of the black-blood contrast technique, its reproducibility was assessed in three more mice (31 ± 4 g) by repeating the acquisition of a mid-ventricular slice with black-blood contrast.The benefit of black-blood over bright-blood contrast was investigated in a subset of mice . All raw data were isotropically zerofilled by a factor of two and filtered (modified third-order Butterworth filter (25)) before Fourier transformation resulting in a reconstructed in-plane voxel size of 100 × 100 μm2.Reconstruction and analysis of data were performed offline using purpose-written x-, y-, and z-directions were obtained by subtracting the respective motion-encoded scan from the phase reference . Magnitude images (for segmentation) were calculated by adding the magnitude of all four scans. Phase maps and magnitude data were exported into binary format and read by a purpose-written software tool to analyze the TPM data in MATLAB . After manually delineating the epicardial and endocardial borders on a frame-by-frame and slice-by slice basis, the measured in-plane velocities (vx and vy) were transferred into an internal polar coordinate system, positioned at the centre of mass of the left ventricle, and expressed as radial (vr) and circumferential  velocities. Furthermore, all velocities were corrected for bulk motion by subtracting global translational velocities from the local velocity components  as:The sign convention for the various velocities used throughout the article follows Ref.t-test. A P-value of 0.05 was considered statistically significant. Furthermore, correlation coefficients were calculated by correlating mean radial velocities in 24 angular segments with the global velocity time course  regression and (2) Bland–Altman analysis using Microsoft Excel 2008 for Apple MacIntosh. The total number of data points available for both analyses is equal to the sum over all time frames and animals. The null hypothesis that the slope in the regression analysis was equal to one was tested using a Student's e course .For each data set of the normal hearts, cardiac structural  and functional parameters were obtained from TIFF images as described before (5), using Amira 4.1 .The flow rates in the validation experiment were quantified to 35.3, 40.6, and 44.7 mL/min and were therefore in excellent agreement with the preset flow rates. The accuracy of the flow rate at the pump was ±0.5 mL/min, whereas the standard deviation, derived from the phase noise in the experiments, for the flow measured with phase-contrast MRI was 0.01 mL/min.Linear regression analysis was used to assess the agreement between velocities obtained by black-blood versus bright-blood methodologies and to assess reproducibility of the black-blood data following repeated acquisitions. Comparisons were made by calculating mean velocities averaged over the entire LV segmentation mask for all time frames, and the slopes and correlation coefficients are listed in Excellent reproducibility for these data was also confirmed by the Bland–Altman-analysis shown in Of the 22 mice scanned, one was excluded due to gradient interference with the ECG and subsequent mistriggering. vφ describes the rotational motion .Global cardiac functional parameters were within published values for normal mice. Particularly, we measured for: LV-mass: 74.1 ± 4.6 mg, end-diastolic volume: 45.8 ± 6.9 μL, end-systolic volume: 12.6 ± 4.9 μL, SV: 33.2 ± 5.2 μL, ejection fraction: 72.9 ± 8.2%, heart rate 468 ± 33 bpm, and cardiac output: 15.5 ± 2.4 mL/min  DENSE have been discussed in Ref.B0 inhomogeneities, off-resonance effects, etc. Linear background phase errors were corrected further using information from an external, static agarose reference, which provided high signal-to-noise ratio due to short T1 times . It cannot be excluded that this difference is caused by the vertical orientation of the mouse in the magnet used in Ref.The main aim of this article was to provide detailed global and regional left-ventricular motion patterns. While twist and torsion angles have been reported before for mouse hearts, this study provides for the first time a detailed motion analysis of the entire cardiac cycle in normal, adult C57Bl/6 mice under isoflurane anesthesia using (phase-contrast) MRI, and followed clinical convention for both the different velocity components and the segmental analysis , 26. WhiTwist angles and torsion were similar to the values reported by Henson et al.  and, morThe proof-of-principle application to the ischemia–reperfusion mouse model  demonstrIn conclusion, this work presents an optimized method based on phase-contrast MRI that allows for a comprehensive assessment of regional cardiac function in mouse hearts at 9.4 T. Black-blood contrast was found to be essential to obtain accurate and reproducible velocity encoding. A detailed analysis was performed to establish baseline values of normal transmural wall motion pattern. This technique will help to investigate systolic and diastolic functions in genetically and surgically manipulated mouse models of human heart disease.