Megaptera novaeangliae) sing a repetitive, stereotyped, socially learnt and culturally transmitted song display that slowly evolves each year. Most males within a population sing the same, slow-evolving song type; but in the South Pacific, song ‘revolutions’ have led to rapid and complete replacement of one song type by another introduced from a neighbouring population. Songs spread eastwards, from eastern Australia to French Polynesia, but the easterly extent of this transmission was unknown. Here, we investigated whether song revolutions continue to spread from the central (French Polynesia) into the eastern (Ecuador) South Pacific region. Similarity analyses using three consecutive years of song data (2016–2018) revealed that song themes recorded in 2016–2018 French Polynesian song matched song themes sung in 2018 Ecuadorian song, suggesting continued easterly transmission of song to Ecuador, and vocal connectivity across the entire South Pacific Ocean basin. This study demonstrates songs first identified in western populations can be transmitted across the entire South Pacific, supporting the potential for a circumpolar Southern Hemisphere cultural transmission of song and a vocal culture rivalled in its extent only by our own.Cultural transmission of behaviour is an important aspect of many animal communities ranging from humans to birds. Male humpback whales ( Birdboundary ,25. The boundary ,24,26. Tboundary . Song isboundary –30. The nd types ,32. By c seasons –35. Unli seasons ,36, hump seasons ,30,37,38Humpback whale song is arranged in a nested hierarchy with multiple levels ,39. At tet al. [In the South Pacific region, changes to humpback whale song may occur in two ways: progressive cultural evolution, and cultural ‘revolution’ . Progreset al.  first obet al. . Subsequet al. ,57,58. Oet al. ,56,59. Iet al. . Such inet al. . Revolutet al. . The undet al. ,63. Howeet al. : individet al. ,57,60,64et al. ,66).a). Here, we investigated whether song revolutions continue to spread in a unidirectional pattern eastward from the central South Pacific (French Polynesia) into the eastern South Pacific (Ecuador) region. Using similarity analyses (Levenshtein distance similarity index (LSI) and Dice's similarity index (DSI)) songs from three consecutive and concurrent years (2016–2018) were quantitatively compared to investigate the direction and strength of connection. The geographical bounds of song transmission are unknown but are hypothesized to be circumpolar, based on recent cultural evolution models [The vocal connectivity of western and central South Pacific populations, and the consistent, unidirectional spread of humpback whale songs from western Australia to French Polynesia raise the question of how far a song may be transmitted eastwards ,58,67,68figure 2n models . This cu. 2. 2.1a; electronic supplementary material, figure S1). Recordings were made during the austral winter breeding season (July–November) from 2016 to 2018 during opportunistic boat-based surveys and with a moored autonomous recorder. Boat-based recordings were made in French Polynesia in 2016 using a HTI 96MIN hydrophone connected to a H4N Pro Zoom recorder . Passive acoustic recordings were collected in 2016, 2017 and 2018 using an Ocean Instruments SoundTrap STD300  in 30 m water (recorder 4 m above the sea floor) at 17°32.860 S and 149°46.148 W . All recordings in Ecuador were boat-based and made in the ‘Bajos de Atacames’ up to 5–10 km offshore from the Esmeraldas River  to Punta Galera . Songs were recorded using a H2a-XLR omnidirectional hydrophone  and a DolphinEar/Pro omnidirectional hydrophone (sensitivity 15 Hz to 20.000 Hz ± 3 dB) connected to a TASCAM DR-40 recorder .Song recordings were collected on the humpback whale breeding grounds in French Polynesia off the island of Mo'orea, and in northern Ecuador off the coast of Esmeraldas . One recording  were all units from one high-quality example of each phrase type present for each location and year, plus any rare unit type not included in those selected phrases [randomForest package [All songs were analysed as spectrograms in Raven Pro 1.6.1 . Song transcription was conducted at the unit level by a human classifier (J.N.S.) following Garland et al. ,41,57,71et al. ,71,72  to compare all phrase strings (n = 1457). The LSI theme similarity matrix was hierarchically clustered and visualized as a dendrogram using average-linkage (UPGMA) clustering to validate the qualitative assignment of phrases to themes . The cophenetic correlation coefficient (CCC) was also calculated to ensure the clustering method chosen provided the best representation of the connections within the data (considered ‘good’ if CCC > 0.8) [Units were transcribed into phrases. Repeating unit strings (phrases) were grouped into themes following the typical theme classification rule of ‘similar sounds in similar positions' ,66, and C > 0.8) ,72,80. TC > 0.8) ,78. The . 2.4n = 19) and the resulting similarity matrix was average-linkage clustered  and bootstrapped 1000 times  and normal bootstrap probability (BP)) using the pvclust package [p-values for each split in the tree, which are regarded as significant if p > 95% for AU [p > 70% for BP [To investigate song sharing, we calculated two similarity indices: (1) the LSI and (2) DSI (see the following paragraph). Once theme assignments were verified, the LSI calculation was performed at the song level as the sequence of themes that made up each song type . For the package  in R. Bo% for AU  and cons% for BP  to ensurhttps://github.com/ellengarland/dice_si). The similarity matrix was clustered (average-linkage) and bootstrapped 1000 times (as for the LSI), and the CCC calculated to ensure the resultant tree structure represented the connections in the data.As an alternative analysis to LSI, DSI was calculated based on the presence and sharing of themes (phrase types) among all singers. This analysis does not rely on any sequence information in the song, simply the presence and sharing of themes . DSI is . 3n = 9) and Ecuador (n = 10) were composed of 41 themes (Four song types (labelled 1–4) identified from 19 singers from French Polynesia . Two initial branches were produced: one included song types 1 (blue), 2 (green) and 3 (orange) and the other song type 4 (grey). Song type 1 (blue) included all singers from French Polynesia 2016, two (of three) from 2017 and all Ecuador 2018 singers. Song types 2  and 3  branched off the song type 1 (blue) cluster at a high level. Song type 4 (grey) included all Ecuador 2016 and 2017 singers and was entirely separated from the song type 1 (blue) cluster, which included the 2018 Ecuador singers. Both hybrid songs (singers 7 and 8) were grouped within song type 1 . Singer 7 was placed on a separate branch to the rest of song type 1 (blue), while singer 8 was nested within the branch based on similarity in theme sequences (figure 2b).The LSI from hierarchically clustered and bootstrapped theme sequences for each singer revealed three major groupings . Song types 1 (blue) and 4 (grey) clustered in a similar way to LSI, but with additional confidence in placement of singers within the dendrogram . However, hybrid singer 7  was grouped with song type 3 (orange) singer 9, due to sharing theme 22 regardless of the sequence order of themes. Finally, regardless of the method and fine-scale placement of hybrid singers, all analyses indicated that there were four song types present across the central and eastern South Pacific over the course of the study  were documented in both French Polynesia in 2016, 2017 and 2018 as well as in Ecuador in 2018, confirming the hypothesis of delayed eastward transmission of song. Thus, the unidirectional song transmission in the South Pacific not only extends from Australia to French Polynesia ,56, but Recent agent-based cultural evolution models of global song transmission suggest the unidirectional song transmission is driven by differences in population sizes as songs spread from large to small populations . We specet al. [Song in both French Polynesia and Ecuador changed through progressive evolution and song revolutions, as is common for South Pacific breeding populations ,56. Proget al.   spread from French Polynesia to Ecuador no earlier than 2016. The French Polynesian version of this song added three new themes between 2015 and 2016, and one of those themes (7a) was present in all song type 1 (blue) songs recorded in Ecuador in 2018   and orange-tufted sunbird (Nectarinia osea) males along dialect boundaries who displayed songs from either dialect [Zonotrichia albicolis) [Finally, hybrid songs provide insights into the song learning process by which singers transition from singing an old song type to a new, novel song . In the  dialect ,94. Whil dialect ,24,25. T dialect . In both dialect ,24,92. B dialect  but rath dialect . A relevbicolis) , where abicolis) . This shbicolis) ,96.Here, we documented both song evolution and revolution, and the presence of hybrid singers which support previous studies on South Pacific humpback whale song dynamics ,60,61,72. 5Here, we documented the first evidence of eastward cultural transmission of songs from the central South Pacific breeding population of French Polynesia across to the eastern South Pacific breeding population of Ecuador. Three song themes were shared between the populations, with the song type being traced back as far as Tonga in the western South Pacific. This demonstrates that humpback whales are vocally connected across the ocean basin. Song transmission between French Polynesia and Ecuador is likely facilitated on overlapping feeding grounds around the West Antarctic Peninsula. This study extends our understanding of the extent of cultural transmission among humpback whale populations in the South Pacific and adds to unravelling the underlying mechanisms of song learning. Further studies are required to confirm whether song revolutions regularly spread from French Polynesia to Ecuador, and if so, at what interval. Further, to evaluate the extent of this cultural phenomenon, future studies should investigate whether songs continue to transmit eastwards from Ecuador (eastern South Pacific) to Brazil (western South Atlantic), and onwards around the Southern Hemisphere. Understanding this cultural phenomenon will provide valuable comparative perspectives to the evolution of complex communication including the evolution of human language and culture. As with humans, the patterns of migration are written into the songs of humpback whales.


Additional studies used were 123I MIBG SPECT, 123I BMIPP SPECT, 18F FDG PET, 67Ga citrate, and 11C hydroxy-ephedrine. A perfusion defect was seen in 69 (31.2%), and an inverse perfusion–metabolism mismatch  was seen in 183 (82.8%) patients. Nuclear imaging has a significant role in evaluating, diagnosing, and prognosticating patients with TTS. As nuclear imaging technology evolves, we will surely gain more insights into this fascinating disorder.Takotsubo cardiomyopathy or Takotsubo Syndrome (TTS) is a reversible left ventricular dysfunction syndrome that is increasingly being recognized. Recent advances in nuclear imaging have allowed us to study TTS in greater detail. We searched the PubMed and Medline databases and identified 53 publications with 221 patients reporting nuclear imaging findings in TTS. The age of the patients ranged from 17 to 87 years and were predominantly women (88.2%). The TTS variant was apical  in 170 (76.9%), mid-ventricular in 23 (10.4%), and basal (reverse TTS) in 2 (0.9%). Cardiac perfusion was assessed using  Takotsubo cardiomyopathy, or Takotsubo Syndrome (TTS), is a reversible left ventricular dysfunction syndrome that was described over two decades ago. In its most common variant, the left ventricle (LV) resembles a Japanese octopus (tako) trapping pot (tsubo), from which it gets the name. Although most of the initial reports of TTS were from Japan, it is now reported in almost every country. It is estimated that 1–2% of all patients presenting with acute coronary syndrome have TTS [TTS is a transient cardiac syndrome, and patients present with chest pain, EKG abnormalities, and elevated cardiac enzymes, often in the setting of acute stress. Although TTS is reversible, complications such as arrhythmia, pump failure, outflow tract obstruction, cardiac rupture, and embolization can cause morbidity and mortality. The Revised Mayo Clinic Criteria is widely used for diagnosing TTS and requires the presence of transient LV systolic dysfunction, absence of obstructive coronary disease, new EKG abnormalities or modest elevation in troponin, and absence of pheochromocytoma or myocarditis . AlthougOver the last decade, nuclear imaging techniques have seen tremendous development and application. Nuclear imaging techniques have allowed us to study in detail several diseases, including TTS, to appreciate its pathophysiology, improve diagnostic accuracy, and provide prognostic information. This narrative review aims to summarize the current literature on the use of nuclear imaging in TTS.We searched the PubMed and Medline databases to identify studies. Search terms included “Takotsubo Cardiomyopathy (MeSH term)”, “nuclear imaging,” and names of individual tracer compounds. References of manuscripts from the initial search were used to find additional manuscripts. Studies published in English, including adults with TTS who underwent nuclear imaging, were eligible to be included in this review. We searched the listed databases from inception to May 2022. Articles that did not have the patient’s details, opinions, comments, letters, and articles not published in English were excluded from the analysis. Two independent clinicians reviewed all articles.99mTc sestamibi (MIBI) SPECT, 99mTc tetrofosmin SPECT, 201Tl SPECT, 82Rb PET, and 13N ammonia PET  SPECT and 123I MIBG SPECT, respectively. The tracers used for perfusion and additional studies depended on the facility’s choice. A perfusion defect was seen in 69 (31.2%), and an inverse perfusion–metabolism mismatch  was seen in 183 (82.8%) patients. No adverse events were reported due to radiotracer injection.From a total of 5590 papers that were assessed for eligibility, we excluded 888 comments, 161 editorials, 1439 letters, 656 reviews, and 2 guidelines. We excluded an additional 2391 papers which did not have data on nuclear imaging. A total of 53 papers with 221 patients were included in the final review . The ageonia PET . AdditioTakotsubo cardiomyopathy, or Takotsubo syndrome (TTS), was first described in Japan in 1990 and was so named because of the resemblance of the heart to a traditional Japanese octopus trapping pot. Since its initial description, the syndrome has been diagnosed worldwide in several settings, including the intensive care unit. With the COVID-19 pandemic, Takotsubo cardiomyopathy has been described both as a complication of COVID-19 infection and as a consequence of the emotional stress associated with social distancing . It is eWith the turn of the century, nuclear imaging has seen rapid advances and increased application in several disciplines. With our ability to engineer targeted tracer compounds and improvement in imaging techniques, we can study the pathogenesis of several diseases in detail, including TTS. Various nuclear imaging techniques have been used to study TTS, including perfusion and metabolic studies. Not only are we able to obtain a global understanding of cardiac metabolic patterns, but also granular patterns including the uptake of individual metabolites such as glucose and fatty acids. We can also image the sympathetic innervation of the heart and identify defects in the same. With all these techniques, we now have a better understanding of TTS. To the best of our knowledge, this is the most exhaustive review of nuclear imaging in TTS to date, with 221 patients. We aim to provide a comprehensive update on the application of nuclear imaging in TTS, the new insights gained on its pathophysiology, and possible applications of this technology in the future.The pathophysiology of TTS is not fully understood, but several postulated hypotheses exist. It is reasonably clear that there is a relationship between TTS and increased levels of stress and catecholamine levels. There are reports of increased incidence of TTS after natural calamities. One such observation was made during the Niigata earthquake when the incidence of TTS increased 24 times higher than baseline near the earthquake’s epicenter . In the 2+, which is thought the be the cause of myocardial damage [s protein to inhibitory Gi protein signaling via the β2-adrenoceptor. This, in turn, protects against the pro-apoptotic effects of intense β1-adrenoceptor activation [Increased sympathetic drive and catecholamine levels are central to the pathophysiology of TTS. Catecholamines induce an increase in intracellular Cal damage . Anothertivation . However2 receptor to epinephrine may cause a prolonged downregulation of the β2 receptor and impaired uptake-1 function. This causes relatively high levels of epinephrine and norepinephrine in the synaptic cleft resulting in the slow recovery of these receptors and transporters compared to more basally located β2 receptors [In addition, it has also been assumed that the increased apical density and sensitivity of the βeceptors .2-adrenergic receptor density increased from the basal toward the apical region [Differences in the regional distribution of cardiac innervation and local adrenoceptor density may be the major determinants behind the distinct patterns of TTS. In a canine model, βl region . The incl region .123I-MIBG imaging (both planar and SPECT) is a vital tool to evaluate sympathetic innervation of the heart. Planar 123I-MIBG cardiac images are analyzed by computing the heart-to-mediastinal (H/M) ratio on both early and late images and the washout rate (WO) of the tracer from the myocardium between early and late acquisitions. In addition, regional tracer uptake is qualitatively assessed on SPECT images using a 5-point score in a 17-segment model. A reduced late H/M ratio (H/Mlate) and an increased WO are associated with a poor prognosis, whereas the role of SPECT analysis is still under investigation. In 2016, Christensen and colleagues demonstrated that 123I MIBG images in TTS showed a lower late (4-h) heart-to-mediastinum ratio (H/Mlate) (2.00 +/− 0.38) and a higher washout rate (WR) (45 +/− 12%) in the subacute state of TTC, both when compared with follow-up  and when compared with the control group in the subacute state  [late and high WR on MIBG imaging in the acute state of TTS may be due to the blocking effect of high circulating levels of epinephrine on norepinephrine reuptake [123I-MIBG SPECT showed reduced uptake at the basal region, indicating a concordance between hypokinetic segment and region of decreased 123I-MIBG uptake [123I-MIBG uptake was found in 21 patients (95%) on early and all patients on late images. This persisted in 50% of patients at three years of follow-up. Given that sympathetic fibers are more susceptible to hypoxia and acidosis, it is plausible that the initial insult destroys the sympathetic fibers before the myocardium is lost. This finding is significant because the denervated myocardium is supersensitive to catecholamines resulting in a higher risk of arrhythmia [In a case of inverted TTS reported by Humbert et al., G uptake . SestiniG uptake . At presrhythmia .123I-MIBG may have prognostic implications. Investigators from the Kindai University Hospital, Japan, retrospectively identified 90 patients with TTS who were divided into two groups based on the timing of LV function improvement: <1 month (S) group and >1 (L) month group [123I MIBG scintigraphy showed lower H/Mlate  and higher WO  in the L group compared with the S group. There were more in-hospital complications in the L group , including higher rates of heart failure  and in-hospital death . These findings suggest that higher sympathetic nervous system activity is associated with a poor prognosis in patients with TTS, and 123I MIBG can be used as a risk stratification tool.Assessing the sympathetic innervation with th group . The sym18F Dihydroxyphenylalanine (DOPA) uptake in 133 patients showed significantly higher uptake in women  [p < 0.001) and in individuals >55 years of age . Although this analysis was not carried out in patients with TTS, using 123I MIBG scintigraphy in this context provides clues as to why older women are more susceptible to TTS.There may also be sex-dependent differences in the cardiac sympathetic outflow. Retrospective analysis of cardiac < 0.001) . The dif82Rb PET/CT in eight, 99mTc sestamibi SPECT in six, and 201Tl SPECT in two. Perfusion defects were seen in 11 (68.7%) patients with TTS and commonly involved the apical or antero-septal-apical left ventricle, despite having patent coronaries. This proportion was much higher than our pooled data, identifying perfusion abnormalities in only one-third of the patients. It is also important to note that the defects do not correspond to any particular arterial territory—a defining feature of TTS that suggest microcirculatory dysfunction rather than epicardial coronary pathology.The role of perfusion abnormalities in TTS is a matter of debate as both increased and decreased perfusion have been described by radionucleotide perfusion studies (RPS). Anderson et al. analyzed the Intermountain Healthcare electronic medical records which contained 16 patients with TTS who had RPS . The tra13N ammonia/82Rb PET in both the acute state and follow-up. In 17 patients, flow in the basal region was increased in the acute state , whereas mid-ventricular  and apical  flow was unchanged between acute and follow-up, and within normal range. Similar findings were also reported in several case reports.  of 123I BMIPP and perfusion were semi-quantitatively determined using SPECT [123I BMIPP abnormalities were exclusively observed in the apical area. As mentioned before, high epinephrine concentrations trigger a switch in intracellular signal trafficking in ventricular cardiomyocytes from stimulatory Gs protein to inhibitory Gi protein signaling. This may lead to downstream signaling that changes myocardial metabolism, perhaps as a protective mechanism. These changes can be detected and followed up with nuclear imaging studies.Similar findings were observed in a prospective study of 18 patients by Kobylecka and colleagues . No regi123I MIBG cardiac scintigraphy with late heart-to-mediastinum ratio (H/Mlate) and washout rate (WR) were used to assess sympathetic activity, in a subset of patients. The data showed a direct correlation between blood glucose levels and norepinephrine levels at admission . In the subset of TTS patients who underwent 123I MIBG cardiac scintigraphy, those with hyperglycemia had lower H/Mlate values at both the acute phase (p < 0.001) and follow-up (p < 0.001). Reduction in blood glucose correlated well with changes in H/Mlate after 24 months of follow-up . Significantly higher mortality  and HF events  were seen in the TTS group with hyperglycemia during follow-up.In this context, the interaction of hyperglycemia and TTS also deserves mention. Its role in prognosis and infarct size has been evaluated in obstructive coronary artery disease and MINOCA . Hypergl18F FDG PET/CT had a significant bearing on the risk of cardiovascular disease events  [18F FDG PET/CT imaging  [p = 0.038), which also predicted TTS risk after adjusting for confounders . Additionally, on average, individuals with the highest AmygA levels developed TTS two years earlier than those with lower levels (p = 0.028). Similar findings were reported in a prospective study conducted by independent investigators, albeit in a smaller sample size [There is emerging evidence about the role of the neuro-humeral axis and the sympathetic stress response in cardiovascular disease. Suzuki et al. demonstrated significantly increased blood flow in the hippocampus, brainstem, and basal ganglia, and significantly decreased blood flow in the prefrontal cortex in the acute phase of TTS using 99m-Tc ethyl cysteinate dimer SPECT . A longi 0.0001)  A dysfun 0.0001) . To testontrols) . It was ple size . These f201Tl chloride and 123I BMIPP. Heart transplantation leads to extrinsic cardiac denervation due to surgical interruption of sympathetic and parasympathetic nerve fibers, and reinnervation may not always occur [123I MIBG showed no significant increase on serial follow-up indicating absence of reinnervation. This case demonstrates that TTS could develop in a denervated heart, although another possibility is limited reinnervation, below the threshold of detection of the MIBG scan. It is also possible that the transplanted heart is hypersensitive to circulating catecholamines due to the up-regulation of β-adrenergic receptors, increasing susceptibility to TTS.While nuclear imaging studies have helped us better understand TTS’s pathophysiology, some observations raise more questions. There are several case reports of patients with TTS whose nuclear imaging findings contradict our current pathogenesis model. One such case is a 67-year-old heart-transplant patient who developed TTS . The patys occur . The extThere have also been case reports of several variants of TTS in the same patient ,79. ThesNuclear imaging has a significant role in evaluating, diagnosing, and prognosticating patients with TTS. At present, neither the Revised Mayo Clinic Criteria nor the criteria by the Takotsubo Cardiomyopathy Study Group (TCSG) incorporate nuclear imaging into the diagnostic algorithm for TTS ,81. GiveOur review, although comprehensive, had several limitations. Firstly, only case reports, case series, and observational studies were included in this review. Additionally, the sample size of the observational studies was small. There was no uniform method of reporting results and imaging features, and most studies did not give additional information, such as coronary angiography or echocardiography findings. The use of stress studies was also unclear in the majority of the cases. Well-designed randomized controlled trials would better answer the questions that we have about the role of nuclear imaging in TTS. Until then, our best data are being collated from observational studies and anecdotal evidence.TTS is a condition characterized by transient ventricular dysfunction. Nuclear imaging of TTS reveals perfusion defects in a minority of patients and metabolic defects in a majority. These defects do not conform to a unique epicardial coronary territory. Moreover, the metabolic defect is almost always out of proportion to the perfusion defect leading to a characteristic ‘inverse-mismatch’ pattern. Nuclear imaging offers the possibility to separately study myocardial perfusion, sympathetic innervation, glucose metabolism, fatty acid metabolism, and myocardial inflammation. In the future, nuclear imaging techniques may be adopted for risk prediction, stratification, and prognostication of TTS. However, more research is needed before nuclear imaging becomes mainstream in evaluating TTS.


Lumbar IVD T2 relaxation times showed significant correlation with PT (P<0.01), GT (P<0.01), TPA (P<0.01), PI-LL (P=0.01), and LLL (P=0.01). No difference was noted between Roussouly subtypes regarding T2 relaxation times at any disc level. Data from questionnaires showed no correlation with T2 relaxation times. Global tilt and T1 pelvic angle were correlated with IVD composition changes (T2 relaxometry). There was no correlation between clinical symptoms and IVD T2 relaxation times.The aim of this study was to verify the relationship between quantitative T2 relaxation measurements of lumbar intervertebral discs (IVDs) and spinopelvic parameters in patients with chronic low back pain. The study was approved by the Clinical Hospital of the Ribeirao Preto Medical School (USP) Ethics Committee, and written consent was obtained from all patients. A total of 455 IVDs from 91 consecutive patients with chronic low back pain were included in this prospective study. All subjects were assessed using the Oswestry Disability Index and visual analogue scale questionnaires and were confirmed to have no other spine diseases except disc degeneration. Spinopelvic parameters including the pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), global tilt (GT), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence minus lumbar lordosis mismatch (PI-LL), and lack of lumbar lordosis (LLL) were measured. The study group was categorized according to the Roussouly classification. Sagittal T2 maps were acquired to extract the IVD relaxation times, and the complete manual segmentation of IVDs at all levels was performed using Display Degeneration of the intervertebral discs (IVD) has a high prevalence and is associated with low back pain -3. The Ninety-one consecutive patients with chronic lumbar pain were included in this cross-sectional and prospective study. There were 56 female patients  and 35 male patients . Inclusion criteria were age greater than or equal to 18 years and chronic low back pain  with recurrent episodes in the last 6 months.Exclusion criteria consisted of scoliosis or spondylolisthesis, vertebral fracture, neoplasia, postoperative status, disabling hip disease, infection, or bone metabolic diseases. Of the 107 evaluated patients, 23 were excluded for the following reasons: 10 individuals with spondylolisthesis, 5 individuals with scoliosis, and 1 individual with vertebral fracture. All individuals were assessed by the Oswestry disability index (ODI) and visual analogue scale (VAS). The study was approved by the Clinical Hospital of the Ribeirao Preto Medical School (USP) ethics committee, and all research was performed in accordance with the current regulations. Informed consent was obtained from all participants of this study.Each patient underwent lateral panoramic radiography acquired with a CR Long Length Vertical Imaging System . Subjects stood with arms supported on a stand, shoulders at 30° of flexion, and elbows slightly flexed according to previous literature  to minim® software  was used to measure spinopelvic parameters and vertebral curvature angles. The following parameters were evaluated  with a 16-channel spinal coil. To avoid possible physiologic daily variations in disc water content, MRIs were acquired in the afternoon. All images of the lumbar spine were acquired in the sagittal plane using the following parameters: field of view=22×22 cm, thickness=4 mm, number of slices=16, and matrix=220×217. A 2D fast spin-echo T2-weighted sequence, echo time (TE)=120 ms, and repetition time (TR)=3900 ms were used for anatomical reference and IVD segmentation. We used a T2 relaxometry multi-echo sequence as follows: TE=20/40/60/80/100/120/140/160 ms and TR=3900 ms.® software  to extract the IVD relaxation times. T2 maps were computed on a pixel-by-pixel basis using an exponential decay model, where S0 is the equilibrium magnetization signal and S(TE) is the signal acquired with the echo time (TE): We generated T2 relaxometry maps using MINC tools and DisplayUsing T2-weighted images, the complete volume of each lumbar IVD was manually segmented . The segThe first examiner, a radiologist with four years of experience, was responsible for spinopelvic measurements and IVD segmentations. The second examiner, a researcher with four years of experience in spinal imaging who was blind to the measurements of the first examiner performed the same measurements to assess interobserver reliability. Participants were categorized into study groups by the two examiners according to the Roussouly classification for the 4 postural subtypes . When dit-test was used to compare the composition of the IVD according to gender. We performed a mixed effects linear regression between the spinopelvic parameters PI, PT, SS, SVA, GT, TPA, LL, TK, PI-LL, LLL and the T2 relaxation times, controlling for the effect of age. Roussouly subtypes and T2 relaxation times were compared with analysis of variance (ANOVA). The correlation between questionnaire data and T2 relaxation time was analyzed using the Spearman correlation coefficient (ρ). The interobserver agreement was analyzed by intraclass correlation coefficient with a 95% confidence interval, considering zero to 0.19 as poor agreement, 0.20-0.39 as fair agreement, 0.40-0.59 as moderate agreement, 0.60-0.79 as substantial agreement, and 0.80-1.00 as almost perfect agreement. All statistical analysis was performed with a statistical software . For this study, a significance level of 5% was adopted. The statistical power (1-β error probability) of our sample (91 subjects) was 0.86 with an α error of 5%.Student's The mean T2 relaxation time was T2=91.3±8.24 ms for men and 91.83±9.41 ms for women. No statistically significant differences in T2 relaxometry values were noted between genders at any disc level.The spinopelvic parameters of our study group are provided in No difference was noted between Roussouly subtypes regarding T2 relaxation times at any disc level.The mean ODI was 23.86±9.41 points  and the mean VAS value was 7.48±1.88 . No statistically significant correlation was noted between T2 relaxation values and questionnaire data at any disc level.The ICC for T2 relaxometry values demonstrated almost perfect inter-observer agreement for manual disc segmentations (ICC: 0.96) and for spinopelvic parameters (ICC: 0.85 to 0.96) .This study assessed the correlation between quantitative T2 relaxation measurements of lumbar intervertebral discs and spinopelvic parameters reports using a consecutive series of 91 patients. We observed a significant negative relationship between T2 relaxometry values and the spinopelvic parameters PT, GT, TPA, PI-LL, and LLL. Roussouly subtype did not correlate with T2 relaxation time. We did not observe a significant correlation between mean T2 relaxometry values at the IVDs and questionnaire data.Patients with lumbar degenerative disease are characterized by anterior sagittal imbalance, loss of LL, and increased PT ,15,20,21First, the SVA measurement can be reduced by postural compensatory mechanisms, such as pelvic retroversion. Therefore, a high PT may “hide” a larger spinal deformity when only the SVA is considered. SVA and PT are related and the magnitude of one affects the other. In patients who may have developed pelvic retroversion (high PT) to compensate for an underlying spinal malalignment and maintain their head over the pelvis (low SVA), the evaluation of the sagittal alignment by SVA alone would not detect their sagittal malalignment. Lafage et al. suggested that PT should be considered together with SVA to detect patients with spinal deformity in the sagittal plane without high SVA due to pelvic compensation . Of noteThe purpose of sagittal misalignment correction surgeries is to achieve a good global sagittal alignment and restore the LL, considering the morphology of the pelvis.We observed no relationship between LL and disc degeneration quantified by T2 relaxometry. However, we identified the individual's LLL calculated by the difference between the observed lordosis and the ideal lordosis estimated by the Schwab formula. We also identified a relationship between the PI-LL, a valuable tool in the intraoperative planning ,27, and Consistent with other studies -31, we Patients with different Roussouly subtypes did not present significant differences in T2 relaxation times of IVD in our study. Of note, the classification of Roussouly et al.  was origWe observed higher T2 relaxation values in the L2-L3 and L3-L4 discs and these values decreased in the upper (L1-L2) and lower (L4-L5 and L5-S1) lumbar spine extremities. It is reasonable to speculate that the L1-L2, L4-L5, and L5-S1 levels offer greater movement in the sagittal plane compared with other levels, given that L1-L2 is closer to the thoracolumbar junction. In addition, L4-L5 and L5-S1 support the largest amount of load due to gravitational force.The T2 values found in the IVD were very close to those reported in the study by Niu et al. , who useA study performed by Menezes-Reis et al.  with asyThere were some limitations in our study. First, our study used a cross-sectional design, and thus it is impossible to infer cause and effect relationships between the variables. Moreover, the study group consisted only of individuals with chronic low back pain, and asymptomatic individuals were not evaluated. Although the radiographic technique did not allow direct evaluation of lower limb compensation, systematic control was performed during the acquisition to prevent small compensatory mechanisms.In conclusion, several spinopelvic parameters were correlated with disc degeneration quantitatively assessed using the T2 relaxometry technique. Given that this study involved the pathophysiology of mechanical association with disc composition, we believe that longitudinal studies with long follow-up are necessary to evaluate the potential future use of T2 relaxometry in clinical practice. To our knowledge, this is the first study correlating spinopelvic parameters GT and TPA with disc degeneration evaluated by T2 relaxometry.


The aim of this study is to identify echocardiographic predictors of transient left ventricle dysfunction after pulmonary valve balloon dilatation (PVBD), in neonates with pulmonary valve stenosis (PVS) and atresia with intact septum (PAIVS) at birth.The study includes patients admitted at the Bambino Gesù Children Hospital from January 2012 to January 2017. Clinical, echocardiographic and cardiac catheterization data before and after PVBD were retrospectively analyzed.Twenty-nine infants were included in the study . The median age was 5.8 ± 7.1 days. Eight patients developed transient LV dysfunction (three PAIVS and five PVS) and comparing data before and after the procedure, there was no difference in right ventricle geometrical and functional parameters except for evidence of at least moderate pulmonary valve regurgitation after PVBD.p < 0.05) in PVS and PAIVS patients.Moderate to severe degree pulmonary valve regurgitation was significant associated to LV dysfunction ( Pulmonary stenosis (PS) is a congenital heart disease characterized by narrowing of the right ventricle outflow tract (RVOT) and, in most severe forms, complete pulmonary atresia . In the The main treatment goal is to achieve anterograde flow across the RVOT in the neonatal period, in order to improve systemic arterial oxygenation.Trans-catheter intervention with pulmonary valve (PV) balloon dilatation (BD), represents primary therapy for neonates with critical PS and PAIVS. Right ventricular features deemeded necessary to perform PVBD include large, tripartite right ventricle without coronary artery connections and coronary dependent circulation or with interrupted coronary arteries .It is widely demonstrated that PV perforation and/or BD is characterized by a high rate of initial success with acute gradient reduction, ductus independence and low rate of re-intervention. Nonetheless, significant left ventricle dysfunction has been described in PV/PAIVS after PVBD . Ronai .1 at an initial dose that ranged between 0.005 and 0.1 ng/kg/min.All patients received intravenous prostaglandin EAfter clinical stabilization, patients were transferred to the catheterization laboratory. The radiofrequency perforation, when necessary, was performed with 2 F cable with 5 W of energy administered for 1–2 seconds under fluoroscopic guidance. Pulmonary valve was dilated with a balloon measuring 1.2–1.4 times the pulmonary annulus. The procedure was considered effective if the RVOT final gradient was less than 30 mmHg.Prostaglandin infusion was discontinued 2–5 days after reaching the goal of adequate anterograde pulmonary blood flow (defined as oxygen saturation >92%). In contrast, ductal stent placement or a systemic-to-pulmonary shunt were the treatment options if an additional shunt was required for impossibility to wean patients off from prostaglandin.Imaging data were collected as described in our previous study .Specifically all patients underwent two-dimensional complete echocardiographic examination, using a Philips iE33  with 8- and/or 12-MHz transducers before and after pulmonary valve balloon dilatation. Images were analyzed with a dedicated offline review software .The echocardiographic views considered were subcostal right and left oblique axis, parasternal long axis, parasternal short axis at the level of ventricle and great arteries, left parasternal (with specific focus on the right ventricle inflow), apical 4- and 5-chambers and suprasternal views. End-diastolic and end-systolic LV volume and RV area and tricuspid Z–score and regurgitation degree were measured in apical 4-chamber view.Functional parameters included manually traced right ventricular fractional area change (e-RVFAC), speckle tracking automatically derived (STAD) RVFAC by 2D (a-RVFAC), Tricuspid Annular Plane Systolic Excursion (TAPSE), systolic wave of the tricuspid valve on the Tissue Doppler Imaging (TDI) and Right and Left Ventricle 2D Systolic Global Longitudinal Strain (RVGLS and LVGLS). According to the American Society Echocardiography guidelines, all right and left ventricular dimensions were evaluated in end-diastolic phase in both apical and parasternal views.The Echocardiographic FAC (e-RVFAC) was estimated with the following calculation: [(RVEDA-RVESA/RVEDA) × 100] and the automatic FAC (a-RVFAC) was measured with a speckle tracking automatically derived RVFAC by 2D-STAD using a standard 4-chamber apical view. The Ejection Fraction (LVEF) was estimated with the following calculation: [(LVEDV-LVESV/LVEDV) × 100] Normal RVFAC value was considered greater than 35% .TAPSE identified the longitudinal right ventricle function positioning the M-mode cursor on the lateral portion of the tricuspid annulus. Normal value was above 16 mm .Tissue Doppler analysis was used to measure systolic tricuspid annulus velocity (Ts’). A velocity below 10 cm/s was considered as a sign of systolic dysfunction.For strain analysis, cine-loops recordings were reviewed offline and analyzed by single expert operator blinded to diagnosis. Analyses were performed using Philips QLAB software version 10.3 . 2D strain was calculated using apical four-chamber view, focused on the right ventricle with a modified apical view, obtaining a complete image of the right ventricle, particularly the free wall. The speckle tracking strain software developed for the left ventricle was applied also to the right one. RVGLS derived by averaging only strain curves from the RV free wall . The normal mean values of RVGLS in children were from −20.80% to −34.10%  and for 10 LVGLS from −16.7% to −23.6%  .Data are expressed as percentages for categorical data and mean ± standard deviation for normally distributed continuous variables.2 test was used to compare categorical variables.Comparison between groups  was carried out by Student’s t-test for continuous normally distributed variables and the χp value less than 0.05 was considered statistically significant.A Statistical analysis was performed by SPSS Statistics for Windows software, version 21.0 .We retrospectively enrolled twenty-nine patients in the study . The median age was 5.8 ± 7.1 days. Twenty-five neonates with critical pulmonary valve stenosis (PVS) and four with pulmonary atresia with intact ventricular septum (PAIVS) were included.Pulmonary valve balloon dilation was performed between one and fourteen days of age. The indications for PVBD were standard for neonates with critical PVS and PAIVS .All patients before the procedure had a normal left ventricle ejection fraction (EF) >57%. After the PVBD, eight patients developed a transient left ventricle dysfunction (five PVS and three PAIVS) with EF <50% calculated by the Simpson’s biplane method.vs 8.7 ± 5.2 days, p = 0.04)  .vs −0.72 ± 1.4, p = 0.839), tricuspid regurgitation  and left  and right  ventricle longitudinal strain, that appear equally reduced in both groups   .vs 0.3 ± 0.9, p = 0.042) and left ventricle volume  developed left ventricle dysfunction   .The aim of the study was to investigate incidence and risk factors for the development of left ventricle dysfunction in neonates with PS or PAIVS undergoing PVBD.Several studies suggest that abnormal intraventricular interaction may be the reason of left ventricle dysfunction with an important prognostic effect on mortality .Since the right ventricle shares myocardial fibers, interventricular septum and pericardium with the left ventricle, it is intuitive that significant changes in geometry and function of one ventricle involves the contralateral one, independently of neural, humoral or circulatory effect .The theory of interventricular interaction and its effect on left ventricle function has been demonstrated also in patients with Tetralogy of Fallot both for volume and pressure overload . PatientAs compared to patients with rToF and PR, patients with PVS/PAIVS show a more severe RV diastolic dysfunction with a restrictive physiology, mainly due to RV ventricular hypertrophy, myocardial disarray and fibrosis .The mechanism involved in altering myocardial performance in the ventricular septum is a consequence of the change in RV volume loading conditions, following right ventricular outflow obstruction relief. Patients who developed LV dysfunction after PVBD had larger right ventricles but not significantly larger left ventricles .In our study, left and right ventricular strains before PVBD are reduced, although not statistically significantly, in patients who develop left ventricle dysfunction. In agreement with Ronai’s study, the greatest increase of right ventricle area after PVBD in patients with left ventricle dysfunction is statistically significant.This evidence has confirmed that the right ventricle volume overload (RVVO) after PVBD, due to the iatrogenic development of pulmonary regurgitation, is a predisposing risk factor for transient left ventricle dysfunction.The underlying mechanism depends on the resultant acute right volume overload, regardless of the reduction of pressure load, which can alter right chamber geometry. This then can cause left ventricle dysfunction due to the known physiological processes of ventricular interdependence and also the decreased relative contribution of left atrial systole to left ventricular filling.Acute right volume overload induces flattening of the ventricular septum resulting from leftward displacement of the septum toward the center of the left ventricle, opposing the normal forces of left ventricle distension. Normal ventricular septal curvature recovers by the end of systole, which opposes the inward motion of the ventricular septum toward the center of the left ventricle during systole contraction. As a result, net shortening along the ventricular septum-to-posterolateral free wall short axis in RVVO is reduced.The regional nature of LV impairment depends on ventricular septal flattening, strongly refutes a systemic mechanism explanation  and shows that transient left ventricle dysfunction is a consequence of acute RVVO .In our study, in all patients the greater impairment of longitudinal regional strain in the septum than in the lateral free wall supports the most accredited theory for transient left ventricle dysfunction and demonstrates that it depends on volume overload and interventricular dependence  and 6. WIn the presence of a severe pulmonary regurgitation, a detrimental shunt due to the wide patent ductus arteriosus can be present. Because of the significant pulmonary regurgitation, blood coming into the pulmonary artery by the wide ductus arteriosus is “drawn” to the right ventricle leading to systemic and coronary stealing. The establishment of this detrimental shunt is sometimes terms as “circular shunt” in the setting of congenital heart disease . HoweverThis is a single-center retrospective study with a small sample size, even for the low percentage of cases due to the rarity of this congenital heart disease. Potential selection biases include the influence of multiple factors such as heart rate, preload and afterload in the echocardiographic evaluation of functional and morphological indices. Studies with a larger sample size and future collaborations with other centers are therefore needed to demonstrate the universality of this observation.Moderate-severe degree pulmonary valve regurgitation predisposes to transient left ventricle dysfunction in patients with PVS and PAIVS after PVBD. The acute right ventricle volume overload, which also influences the left ventricle through the known pathophysiological mechanisms of ventricular interdependence, is the implied mechanism. This hypothesis could be a starting point for defining features of patients at higher risk to develop ventricular dysfunction and to draw up a protocol for greater surveillance for improving clinical management to ensure a better outcome for these patients.10.7717/peerj.14056/supp-1Supplemental Information 1Click here for additional data file.


Radiomics is emerging as a promising and useful tool in cardiac magnetic resonance (CMR) imaging applications. Accordingly, the purpose of this study was to investigate, for the first time, the effect of image resampling/discretization and filtering on radiomic features estimation from quantitative CMR T1 and T2 mapping. Specifically, T1 and T2 maps of 26 patients with hypertrophic cardiomyopathy (HCM) were used to estimate 98 radiomic features for 7 different resampling voxel sizes (at fixed bin width), 9 different bin widths (at fixed resampling voxel size), and 7 different spatial filters (at fixed resampling voxel size/bin width). While we found a remarkable dependence of myocardial radiomic features from T1 and T2 mapping on image filters, many radiomic features showed a limited sensitivity to resampling voxel size/bin width, in terms of intraclass correlation coefficient (> 0.75) and coefficient of variation (< 30%). The estimate of most textural radiomic features showed a linear significant (p < 0.05) correlation with resampling voxel size/bin width. Overall, radiomic features from T2 maps have proven to be less sensitive to image preprocessing than those from T1 maps, especially when varying bin width. Our results might corroborate the potential of radiomics from T1/T2 mapping in HCM and hopefully in other myocardial diseases. It is characterized by left ventricular (LV) hypertrophy, myofibrillar disarray, and myocardial fibrosis. Cardiac magnetic resonance (CMR) imaging has an important role in diagnosis, risk stratification, and treatment planning in HCM and, according to the European Society of Cardiology guidelines, it should be performed, at least as an initial evaluation, for all HCM patients2.Hypertrophic cardiomyopathy (HCM) is a genetically determined disease that affects about 1:500 people in the general adult population4. Furthermore, late gadolinium enhancement (LGE) imaging enables the identification of focal myocardial fibrosis, which has been demonstrated to have a negative prognostic value in HCM patients4. More recently, cardiac T1 and T2 mapping techniques have been employed to obtain a more quantitative evaluation of myocardial tissue characteristics. Previous studies have consistently found that T1 and T2 values, as well as extracellular volume (ECV) values obtained from pre- and post-contrast T1 maps, are increased in HCM patients and have a potential prognostic role11. Actually, both native  T1 and ECV values are considered markers of myocardial fibrosis12. On the other hand, T2 mapping is currently considered the gold standard for the evaluation of myocardial edema. Increased T2 values, probably related to low grade myocardial inflammation and dilated lymphatic channels14, have been demonstrated in HCM patients and have been proven to be associated with an increased arrhythmic risk16, as well as with more severe myocardial injury17. However, the usefulness of these mapping techniques is limited by a partial overlap of T1 and T2 values between HCM patients and healthy controls, as well as between HCM patients and patients with other myocardial diseases21.Actually, CMR imaging is considered the gold standard for the evaluation of ventricular morphology and function, as well as for the assessment of ventricular wall thickness22. The underlying idea is that medical images are data containing objective and quantitative information, which is not obtainable from qualitative visual inspection as usually performed in routine clinical practice. In addition to other available data from demographics, pathology, blood biomarkers, and genomics, radiomic features can be used for diagnostic, prognostic or predictive purposes exploiting statistical or machine learning (ML) methods24.Radiomics is a novel tool that involves the extraction of a large number of quantitative morphological and textural characteristics  from digital medical images30. Recently, radiomics has aroused as a useful tool for unveiling myocardial tissue characteristics in HCM patients36. In this regard, previous studies focused mainly on traditional T1-weighted, T2-weighted, cine, and LGE images35. However, given their inherent quantitative nature, T1 and T2 maps might be particularly suitable for radiomic analysis. So far, only a few studies have applied texture analysis to T1 maps in patients with HCM36. They have found texture features able to discriminate among hypertensive heart disease (HHD), HCM, and healthy subjects21, between HCM patients with different genetic mutations20, as well as between LGE+ and LGE− patients36.While radiomic analysis has been mainly applied in the field of oncology, there is a growing interest in improving the diagnostic accuracy and prognostic value of CMR imaging by exploiting radiomic techniques38. Several previous studies have assessed the sensitivity of radiomic features estimation to various elements in computed tomography (CT)41 and nuclear medicine (NM)43 imaging, as well as in magnetic resonance imaging (MRI), for various applications55. On the other hand, only three studies have assessed some of these issues for CMR imaging58. In particular, Jang et al.56 have investigated both test–retest repeatability, as well as inter- and intra-observer reproducibility, in phantoms, healthy participants, and patients who were referred for clinical CMR imaging. They have observed different repeatability patterns among acquisition sequences in in vivo test–retest studies. Moreover, in an inter- and intra-observer reproducibility analysis, 32–47% and 61–73% out of 1023 features, respectively, were identified as reproducible, showing intraclass correlation coefficient (ICC) ≥ 0.8. Across all analyses, first order and gray level co-occurrence matrix were the most frequently identified reproducible radiomic feature classes. Another CMR imaging study by Jang et al.57 has evaluated, in a group of healthy participants and in a heterogeneous group of patients, the sensitivity of radiomic features estimate to changes in acquisition sequence parameters including flip angle, in-plane spatial resolution, slice thickness, and parallel imaging technique. As a whole, they have found that approximately 60% of the 4007 considered radiomic features were robust to changes in any acquisition parameters , with qualitative acquisition sequences  and quantitative T1/T2 mapping most sensitive to changes in in-plane spatial resolution and flip angle, respectively. Alis et al.58 have evaluated the inter-observer reproducibility of radiomic features, as well as the influence of cardiac phases  on radiomic features estimation, from non-enhanced cine CMR images of healthy subjects. For the inter-observer analysis, they have found that the number of radiomic features with ICC > 0.8/0.85/0.9 changed with different phases of the cardiac cycle, and that texture features belonging to the gray level size zone matrix showed the worst performance. Moreover, approximately 55% out of 352 radiomic features showed a variability (in terms of coefficient of variation) > 20% through the cardiac cycle, with gray level dependence matrix and gray level run length matrix classes demonstrating less variability compared with other feature classes.Despite the increasing interest in radiomics of CMR imaging, its proper application deserves some caution and a preliminary assessment of possible radiomic features dependence on various factors. Indeed, each step of the radiomic workflow  could influence features estimation, thus potentially affecting their discriminative or predictive power60. In particular, image interpolation at the same voxel size is a common and recommended practice  to reduce any heterogeneity in acquisition voxel size, while image discretization is required to make texture feature estimation computationally less burdensome59. Moreover, the application of spatial filters before radiomic features estimation could allow uncovering further tissue characteristics. Notably, such a preprocessing actually alters acquired image data and possibly their radiomic characteristics. Nonetheless, so far, no work has specifically assessed the impact of both image resampling/discretization and spatial filtering on the estimate of radiomic features from CMR imaging. Therefore, this work aimed to comprehensively assess, for the first time, the effect of preprocessing—in terms of voxel size resampling, map values discretization, and spatial filtering—on radiomic features estimated from CMR T1 and T2 mapping in a group of HCM patients.Image resampling and discretization, as well as spatial filtering, are some steps of the radiomic workflow that may be performed as preprocessing before the radiomic features extraction from the acquired image data2. Clinical characteristics of the patient group are detailed in Table We retrospectively identified 26 subjects , referred for clinical CMR imaging between November 2013 and July 2020 for known or suspected HCM, for whom a comprehensive MRI study including both T1 and T2 mapping sequences was performed. The HCM diagnoses followed the latest European Society of Cardiology guidelines and were based on the presence of LV wall thickness ≥ 15 mm in one or more myocardial segments, not explained solely by loading conditionsAll CMR imaging examinations were performed using a 1.5 T MRI scanner system  equipped with 45 mT/m gradients strength and a 12-channel phased array coil.Cine images were performed in the 2- and 4-chamber view planes (3 slices each) and in short-axis view (8–14 slices encompassing the entire LV), using a TrueFISP sequence .61. Pulse sequence parameters were as follows: TE/TR = 1.14/2.5 ms, flip angle = 35°, matrix size = 126 × 192, in-plane resolution ranged from 1.77 mm × 1.77 mm to 2.34 mm × 2.34 mm, typical field of view = 380 mm × 275 mm, slice thickness = 8 mm. T2 maps were obtained utilizing a T2-prepared TrueFISP sequence62 with the following parameters: T2 preparation time = 0/24/55 ms, TR = 4 × R–R, flip angle = 70°, matrix size = 126 × 192, in-plane resolution ranged from 1.77 × 1.77 mm to 2.34 × 2.34 mm, typical field of view = 380 mm × 275 mm, slice thickness = 6 mm.Both T1 and T2 maps were obtained in the short axis view . T1 mapping was performed utilizing a modified look-locker inversion recovery (MOLLI) pulse sequence with a 3–3–5 acquisition schemeThen, 10–15 min after intravenous administration of 0.2 mmol/kg of gadolinium DTPA , gadoteric acid  or gadoteridol , LGE images were acquired in 2- and 4-chamber view of the LV (3 slices each), as well as in the short-axis view (8–14 slices encompassing the entire LV) using a 2D phase-sensitive inversion recovery (PSIR) sequence .64. ROIs were delineated on T1 and T2 maps separately, avoiding voxels with potential partial volume effect. Supplementary Figure For each subject, a region of interest (ROI) covering the entire myocardium was manually segmented by a single expert radiologist in cardiac MRI, with 15 years of experience, using 3D Slicer (Version 4.11.2)59). The original in-plane spatial resolution ranged from 1.77 mm × 1.77 mm to 2.34 mm × 2.34 mm across patients for both T1 and T2 maps. Therefore, T1 and T2 maps were resampled to an in-plane isotropic spatial resolution of 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, and 2.4 mm. Resampling voxel size was performed for different bin widths (see below).Given that T1 and T2 maps allowed acquiring only a single slice, resampling voxel size was performed through 2D interpolation by using the B-spline interpolation algorithm , bin width values of 3.60 ms, 3.95 ms, 4.30 ms, 4.65 ms, 5.00 ms, 5.35 ms, 5.70 ms, 6.05 ms, and 6.40 ms were employed for T1 maps, while bin width values of 0.49 ms, 0.50 ms, 0.51 ms, 0.52 ms, 0.53 ms, 0.54 ms, 0.55 ms, 0.56 ms, and 0.57 ms were employed for T2 maps. Indeed, given that the median (across HCM patients) range of T1 and T2 values  was 265 ms and 26 ms, respectively, bin width values were chosen in such a way that the number of quantization levels of T1 and T2 maps was within the range of 30–130, for each HCM patient. This approach, adopted also in previous technical studies54, has the potential to limit variability in radiomic features estimation66.T1 and T2 maps discretization was carried out following a fixed bin width approach, as recommended by the Image Biomarker Standardisation Initiative (IBSI) when dealing with quantitative data66.Different spatial filters were applied on T1 and T2 maps: 2D wavelets (Daubechies 3) yielding four filtered maps , gradient magnitude of the map , the square of the map values , and the square root of the absolute map value . Specifically, in order to restrict the large number of possible combinations, image filtering was performed at fixed resampling in-plane isotropic spatial resolution of 2.1 mm, and at fixed bin width of 6 ms and 0.56 ms for T1 and T2 maps, respectively, yielding median (across subjects) numbers of quantization levels between 30 and 13067 (Version 3.0.1) with Python (Version 3.7.3), running on a MacBook Air (macOS Version 10.14) with a 1.8 GHz Intel Core i5 CPU.All preprocessing steps  and subsequent radiomic features estimation were carried out by using the open source PyRadiomics libraryGiven that the used acquisition sequences allowed obtaining T1 and T2 maps on a single slice, the 2D versions of radiomic features were considered. For each ROI and preprocessing combination, in terms of resampling voxel size and bin width, a total of 98 features were obtained: 9 2D-shape features, 16 first order features , and 73 second order features  from gray level co-occurrence matrix , gray level run length matrix , gray level size zone matrix , gray level dependence matrix , and neighborhood gray tone difference matrix . Second order features estimation was performed according to the Chebyshev norm with a distance of 1 pixel. GLCM and GLRLM features were computed from each 2D directional matrix  and averaged over 2D directions.For each ROI and spatial filter applied on T1 and T2 maps, a total of 89 features were estimated, i.e. all the above features but the shape features. Indeed, given that shape features are usually estimated regardless of the applied image filter, they were not included in our analysis.All radiomic features were computed in accordance with the definitions provided by the IBSI, with shape features computed in 2D instead of the proposed 3D version. It is worth noting that the first order feature of Kurtosis calculated by PyRadiomics was in accordance with the IBSI except for an offset value .A.For each bin width, the effect of using different resampling voxel sizes.B.For each voxel size, the effect of using different bin widths.C.At fixed resampling voxel size and bin width, the effect of using different spatial filters.In this study, three different effects on radiomic features estimation were assessed for T1 and T2 maps singularly:69. In particular, the two-way mixed effects model, with single rater and absolute agreement, was selected. Accordingly, the ICC coefficient was calculated as:R = mean square for rows , MSE = mean square for error, MSC = mean square for columns , n = number of subjects and k = number of raters, with ICC matrices realized considering each resampling voxel size, quantization bin width or image filter as a rater. ICC values range between 0 (maximum variability) and 1 (minimum variability) and express the variability of radiomic features estimate associated with the effect of interest with respect to the variance between subjects . Radiomic features were stratified based on their degree of relative variability52: high (ICC ≤ 0.5), considerable (0.5 < ICC ≤ 0.75), moderate (0.75 < ICC ≤ 0.9), and low (0.9 < ICC ≤ 1) relative variability.For each effect of interest, any variability in radiomic features estimate was assessed through ICC analysisIn order to characterize in greater detail and absolutely the variability in radiomic feature estimate, an additional analysis of the coefficient of variation (CV) was performed. In particular, CVs were computed as the percentage ratio between standard deviation and absolute mean values of features estimate obtained by varying one element of interest  while fixing the others. Accordingly, this yielded 26 × 9 CVs for effect A , 26 × 7 CVs for effect B , and 26 CVs for effect C .70. This technique accounts for non-independence among observations  using analysis of covariance (ANCOVA) to statistically adjust for the variability between subjects. A p-value < 0.05, adjusted for multiple comparisons using Bonferroni correction, was considered significant.Any linear correlation between radiomic features estimate and resampling voxel size or bin width was assessed by a repeated measures correlation analysis, namely rmcorr71.Statistical analysis was carried out by using R (Version 3.6.2) software package in the RStudio (Version 1.2.5033) environmentThe entire time taken by the PyRadiomics tool to extract all the combinations of radiomic features for effects A or B was approximately 35 s, while the estimation process for effect C took approximately 10 s.ICC results for the effects of interest A and B are reported in Figs. For effects A and B, Table The results of the analysis of the linear correlation between radiomic features estimate and voxel size/bin width are reported in Supplementary Tables 36. By using conventional CMR imaging , radiomic analysis has allowed discriminating between HCM patients and healthy controls31, as well as distinguishing among different aetiologies of left ventricular hypertrophy, such as HCM, HHD, cardiac amyloid, and aortic stenosis32. Moreover, some studies have focused on the prognostic role of radiomic analysis of LGE images in HCM, suggesting that texture features are related to the arrhythmic risk35 and adverse clinical outcome34. Notably, only a few pilot HCM studies36 have applied radiomic analysis to T1 maps. Specifically, two studies21 have focused on the diagnostic capability of radiomic analysis to discriminate between healthy controls and HCM/HHD patients. Also, Neisius et al.36, have found that radiomic analysis applied to T1 maps was able to distinguish between LGE+ and LGE–, identifying a subgroup of subjects in whom gadolinium administration could be safely avoided. Wang et al.20 have found that radiomic analysis of T1 maps can discriminate HCM patients with different mutations of sarcomere-related genes.Recently, some studies have applied radiomic analysis to CMR imaging in order to assess whether this tool could reveal myocardial phenotypic alterations in HCM patients72. Nonetheless, to the best of our knowledge, this is the first study aimed at assessing the effect of both image resampling/discretization and spatial filtering on radiomic features estimated from CMR T1 and T2 maps. Thus, in a group of HCM patients, we performed a relatively comprehensive analysis, which considered multiple elements such as voxel size resampling, T1/T2 values discretization, and spatial filtering.Previous studies have investigated the effect of image preprocessing on radiomic features estimation as a function of various factors, which include imaging technique/modality and anatomical region59. For both T1 and T2 maps, we found that textural features belonging to GLCM and NGTDM classes showed moderate relative variability (0.75 < ICC ≤ 0.9) when varying resampling voxel size, except for a limited number of radiomic features  were selected using the same criterion , allowing a comparison between the results of T1 and T2 maps. A remarkable difference between T1 and T2 maps in sensitivity of radiomic features estimation to discretization was found. In general, textural features estimated from T1 maps showed higher variability than their estimates from T2 maps (ICC > 0.75). Only a limited number of T1 maps textural features were characterized by ICC > 0.75  have a significant linear correlation between their estimates and bin width  T1 and T2 maps, we observed a relevant sensitivity of both first order and textural features estimates to image filter, with ICC ≤ 0.5  images. In this regard, the IBSI has proposed a new reference manual, in order to define and standardize the implementation of image filters in radiomics software36, some information about image preprocessing was still missing. For instance, none of these studies have reported whether and how image discretization was performed . Furthermore, the studies conducted by Neisius et al.19 and Shi et al.21 have acquired images with different in-plane spatial resolutions  and employed slightly different preprocessing steps . This could partly explain the obtained different results in terms of discriminative radiomic features and accuracy.The revealed effect of resampling voxel size and bin width on the estimate of myocardial radiomic features from T1 and T2 mapping, albeit limited in many cases, sustains the importance of reporting/describing in detail these aspects in clinical and research studies. In this regard, while previous studies involving myocardial T1 mapping have described the radiomic features extraction process quite exhaustively36 have exploited only T1 mapping, mainly because of its capability of revealing myocardial fibrosis. However, T2 maps are considered the gold standard for the evaluation of myocardial edema, which is a well-known negative prognostic factor in HCM16. Moreover, although T2 mapping is not per se capable of evaluating myocardial fibrosis, texture analyses might theoretically overcome this limitation, unveiling myocardial structural heterogeneity due to myofibrillar disarray and fibrosis27. Therefore, given also that, overall, radiomic features from T2 maps have proven to be characterized by a lower sensitivity to image resampling and discretization than radiomic features from T1 maps , radiomics from T2 mapping might be exploited to obtain a complementary characterization of HCM, albeit this lower sensitivity does not necessarily imply higher discriminative or predictive power. In addition, it should be noted that, for both T1 and T2 mapping, the sensitivity of several radiomic features to resampling voxel size and bin width resulted rather independent of bin width and resampling voxel size, respectively. Moreover, only a limited number of radiomic features showed high relative variability (ICC ≤ 0.5) associated with different resampling voxel size or bin width. Some radiomic features with ICC > 0.75 still presented high variability (> 30%) in terms of CV for single subjects, suggesting that such radiomic data from different centers should be compared or pooled with caution.So far, previous HCM radiomic studies73. Furthermore, the main aim of our exquisitely technical study was to assess the effect of image resampling and discretization on radiomic features estimated from typical cardiac T1 and T2 maps. Accordingly, we focused on a single short-axis slice, located where myocardial thickness was maximum and myocardial changes were assumed to be more severe, obtaining hence minimum partial volume effects, which can greatly affect regions of thinner myocardial segments. Moreover, this is a retrospective study that has enrolled subjects referred for clinical/routine CMR imaging, which requires avoiding too long acquisition times especially for non-collaborative patients. Second, myocardial T1 and T2 maps can be affected by noise, as well as by possible fitting errors and patient motion. In this regard, while appropriate denoising filters applied on T1- and T2-weighted images can be used to improve the precision and accuracy of computed T1 and T2 maps75, we adopted no denoising method. Third, in this technical study involving HCM patients, no clinical/diagnostic results tailored to this disease were reported. In this regard, in order to avoid any potential confounding effects in our analysis, we preferred to enroll only a group of homogeneous subjects with the same pathology. Therefore, this preliminary technical radiomic study on T1 and T2 mapping can be helpful and prodromic for further clinical studies on HCM. Nonetheless, we feel our analysis framework could be applied to other cardiac populations likely obtaining similar findings, albeit that would need further experimental studies to be confirmed. Fourth, image resampling and discretization are only two of the various steps of the radiomic pipeline, albeit important and recommended by the IBSI guidelines59. The issue of standardization in radiomic studies can involve additional factors, such as scanner performances, acquisition protocols, acquisition sequence parameters, and data analysis methods. However, we feel the results of our study can represent a potentially helpful step toward the standardization of radiomics in cardiac magnetic resonance imaging. Indeed, image resampling and discretization modify de facto acquired image data and possibly their radiomic characteristics. Therefore, professionals and researchers executing or planning clinical or research studies should be aware of this critical aspect of radiomics in cardiac magnetic resonance imaging and its entity for both T1 and T2 mapping. As for the practical implications of this study, we note that radiomic techniques allow extracting hundreds of features. In clinical and research studies employing radiomics and artificial intelligence methods, even when enrolling numerous subjects, it is hence mandatory to apply appropriate methods of features selection, in order to avoid any possible bias due to overfitting and obtain reliable results. While supervised or unsupervised methods of features selection can be used76, a limited sensitivity to image resampling and discretization can represent an additional criterion for selecting features. This does not necessarily imply higher discriminative or predictive power in clinical or research studies, which might also depend on the specific effect size associated with selected features, but still can improve reproducibility of results and comparison/pooling of data from different centers.We recognize and submit the following potential limitations and implications, respectively, of our study. First, while we analyzed only single slice acquisitions of T1 and T2 mapping, in HCM patients, myocardial changes may involve also visually non-hypertrophied myocardial segments. Therefore, a whole-heart coverage might provide a more comprehensive evaluation of disease burden and increase the diagnostic performance of CMR imaging. However, for a global/diffuse disease, it is considered adequate to analyze a single ROI on mid-cavity short-axis mapToward an optimization and standardization in radiomic applications, any potential dependence of radiomic features on various aspect of the radiomic workflow should be possibly taken into account when planning a clinical or research study. Nowadays, there is a growing interest in exploiting radiomic techniques in various clinical applications. In particular, the study of myocardial diseases represents an emerging and promising field of application. In this HCM study, while we observed a sensitivity of myocardial radiomic features from T1 and T2 mapping to some conventional image preprocessing procedures such as image resampling/discretization, this effect was very remarkable only when considering image filtering. Indeed, the sensitivity of radiomic features to different resampling voxel sizes and bin widths was limited for many textural radiomic features, as well as for shape and first order radiomic features. The estimate of most textural radiomic features showed a linear significant correlation with resampling voxel size and bin width. In general, radiomic features from T1 mapping were more sensitive to image preprocessing than radiomic features from T2 mapping, especially when varying bin width. Overall, our results might corroborate the potential of radiomics from T1 and T2 mapping in HCM and hopefully in other myocardial diseases.Supplementary Information.


There were 3 major complications (3%), all patients recovered without any sequelae. At follow-up  47 (59%) patients were alive, 11 (13%) dead, 15 (18%) underwent cardiac transplantation, and 8 (9%) were lost to follow-up. Death/cardiac transplantation occurred within 3 years from RV-EMB. All patients with an acute myocarditis survived. NT-pro-BNP, echo parameters, and invasive hemodynamics correlate independently with death/cardiac transplant. Conclusion: Hemodynamic invasive data and morphological findings in RV-EMB complete clinical diagnosis in children with suspected CMP/myocarditis and provide important information for further clinical management. Objective: The study objective is assessing findings and outcome in children with suspected cardiomyopathy (CMP) or myocarditis undergoing cardiac catheterization with transcatheter right ventricular endomyocardial biopsy (RV-EMB). Methods: All consecutive children undergoing cardiac catheterization with RV-EMB for suspected CMP/myocarditis between 2002–2021 were analysed regarding clinical presentation, cardiac biomarkers, periprocedural management, hemodynamic, histological/immunohistological findings, and outcome. Results: Eighty-five RV-EMBs were performed in 81 patients at a median age of 6.8 (IQR 9.9) years and a bodyweight of 20 (32.2) kg. Histological/immunohistological findings of RV-EMB revealed dilated CMP in 10 (12%), chronic myocarditis in 28 (33%), healing myocarditis in 5 (6%), acute myocarditis in 9 (11%), other heart muscle diseases in 23 (27%) , no conclusive histology in 7 (8%), and normal histology in 3 (4%) patients. Median LVEDP was 17 mmHg (IQR 9), LAP 15 mmHg (10), and PVR 1.83 (1.87) Wood Units/m Reduced systolic or/and diastolic myocardial function may be caused by myocardial inflammation due to acute or chronic, mostly viral myocarditis or due to acute cardiac decompensation in children with primary/former cardiomyopathy (CMP) ,3,4,5,6.Acute myocarditis can show a very heterogenous clinical presentation from asymptomatic solitary electrocardiographic abnormalities, through fulminant acute heart failure to sudden cardiac death ,3,5, andNevertheless, especially in children, RV-EMB are not routinely performed in many centres due to concerns regarding the procedural risks  ,17. DataTherefore, aim of this study was to evaluate hemodynamic and histological findings of cardiac catheterization with RV-EMB as standard of care in children treated for myocarditis/CMP and their potential relation to later clinical outcome.This is a single centre, retrospective, longitudinal analysis of a paediatric population with suspected viral myocarditis or CMP between 2002 and 2021 (20 years). We included all consecutive patients undergoing cardiac catheterization with RV-EMB performed for diagnostic work-up due to newly diagnosed, severe systolic or diastolic myocardial left ventricular dysfunction associated with ventricular dilatation, hypertrophy, or restriction. Clinical presentation and findings on two-dimensional transthoracic echocardiography were suspicious of myocarditis, CMP  or systemic ventricle failure for unknown reasons. Purpose of RV-EMB was to confirm or rule out the diagnosis of myocarditis or CMP. ®) were taken with a Cordis® Biopsy forceps 5.5 French (Ref. Nummer 504-300). A coronary artery angiography ruled out coronary abnormalities such as abnormal left coronary artery originating from the pulmonary artery, coronary artery fistula, or myocardial bridging in all patients. In case of coronary abnormalities, no RV-EMB was performed.Eighty-two (96%) transcatheter RV-EMBs were performed antegradely (using venous access and antegrade right heart catheterization). In three patients (4%) with single ventricle physiology a retrograde arterial approach was used. Site of RV-EMB was the apical or septal region of the right ventricle (RV) in all procedures and at least 6 separate biopsies  clinical presentation and biomarkers (NT-pro-BNP starting from 2010), (2) hemodynamic findings of cardiac catheterization, (3) peri-procedural course of cardiac catheterization, (4) hemodynamic findings of cardiac catheterization, (5) histological/immunohistological findings of RV-EMB, and (6) outcome. Analysis of peri-procedural course included anaesthetic data such as new establishment of inotropic support  during cardiac catheterization and catheter-related complications. Further analysis included review of all available hemodynamic data including left ventricular end-diastolic pressure (LVEDP), left atrial pressure (LAP) or pulmonary capillary wedge pressure, and mean pulmonary artery pressure (mPAP). The outcome and survival of this cohort was assessed over a period of 658 (IQR 1337.5) days. Z-scores for echocardiographic parameters were taken from Pettersen et al. .®  fHistological diagnosis of myocarditis may influence further individual patient management because myocardial dysfunction may potentially be completely reversible ,6,19,33.Importantly, histological examination together with PCR in heart biopsy specimens allows an etiological diagnosis in most cases . HistopaRegarding the impact of RV-EMB findings on specific medical treatment  one must consider that some of these findings may also represent viral re-activation/persistence in myocardial cells or lymphocytes, rather than acute (systemic) viral infection. This is illustrated by the high amount of HHV6/7 in our study and from the fact that only five out of nine patients with histological acute myocarditis had a positive viral load in RV-EMB. The survival function in relation to the most frequent histological findings showed no significant difference among the survival of the groups with different diagnoses. Of note is the favourable clinical course of the patients with an acute myocarditis. On the other hand, almost half of the patients with a chronic myocarditis, dilated, restrictive and toxic CMP had an unfavourable outcome resulting in death or necessity for heart transplantation within three years from RV-EMB. One of the objectives of this study was to determine predictors of poor outcomes, defined as requirement for cardiac transplantation or death. In our cohort 18% received cardiac transplant and 13% of patients died . InteresTroponin in the paediatric population is a marker that displays cardiac injury quickly and accurately also in myocarditis ; howeverThis study bares all limitations of a retrospective analysis. Further, other parameters such as cardiac MRI or genetic results were not evaluated, as well as an RV-EMB is rarely performed in patients below 1 year of age due to technical difficulties. The long study period is a strength of the study; however, clinical approaches changed over the last 20 years. In the future, larger paediatric studies with larger paediatric patient populations are needed and should especially evaluate the clinical impact of right ventricular endomyocardial biopsy results on further specific treatment and management of these patients during follow-up . Lastly,Hemodynamic invasive data and histological/immunohistological findings are important for the definite diagnosis of myocarditis and different entities of cardiomyopathies, helping to stratify further clinical management and to estimate individual prognosis. In fact, all patients with an acute myocarditis survived. LV-EF% on echocardiography, hemodynamic data, NT-pro-BNP, and histology diagnosis help to predict unfavourable outcome. These patients might benefit from an earlier mechanical circulatory support in order to allow survival until transplantation.