T1 Mapping Research Articles

Changes in inflammatory edema and fat fraction of thigh muscles following a half-marathon in recreational marathon runners.

It is known that microtrauma exists in the thigh muscles after long-distance running such as the half-marathon. Moreover, training characteristics of long-distance runners may influence the specificity of the distribution of muscle fiber types in the thigh and affect muscle responses to lipid metabolism. However, the specific changes in microtrauma and intramuscular lipid in thigh muscles after a half-marathon are unknown. A cohort of 20 healthy recreational marathon runners was recruited to complete a half-marathon. MRI T2 mapping and 6-echo q-Dixon sequences were employed at baseline (P1), 2-3h after running (P2), and 1day after running (P3). Inflammatory markers (the T2 values) and intramuscular fat fraction (the proton density fat fraction, PDFF) were measured in thigh muscles to detect microtrauma and intramuscular lipid changes, respectively. One-way analysis of variance showed significant time effects for T2 values and PDFF. Post hoc analysis of the 14 datasets collected at three time points revealed significantly higher T2 values in all thigh muscles after running (all p<0.05). Significant differences in T2 values persisted for all thigh muscles at P3 compared to P1 (all p<0.05). The PDFF of the vastus lateralis and vastus medialis was significantly decreased at P2 compared to P1 (p<0.05). No significant differences in PDFF were observed for the thigh muscles at P3 compared to P1. The manifestations of inflammation edema and intramuscular lipid investigated through MRI may offer valuable insights for recreational marathon runners regarding the lower limb movement characteristics during half-marathon running.

Feasibility and Reproducibility of T2 Mapping Compared with Diffusion-Weighted Imaging in Solid Renal Masses.

Accurate prediction of renal mass subtypes, along with the WHO/ISUP grade and pathological T (pT) stage of clear cell renal cell carcinoma (ccRCC), is crucial for optimal decision making. Our study aimed to investigate the feasibility and reproducibility of motion-robust radial T2 mapping in differentiating lipid-poor angiomyolipoma (MFAML) from RCC and characterizing the WHO/ISUP grade and pT stage of ccRCC. Finally, 92 patients undergoing renal radial T2 mapping and ZOOMit DWI were recruited. The T2 values and apparent diffusion coefficient (ADC) were analyzed. Correlation coefficients were calculated between ADC and T2 values. Notably, ccRCC exhibited higher T2 and ADC values than MFAML (p < 0.05). T2 values were lower in the higher WHO/ISUP grade and pT stage of ccRCC (all p < 0.05). ADC showed no significant difference for pT stage (p = 0.056). T2 values revealed a higher area under the curve (AUC) in evaluating the WHO/ISUP grade compared to ADC (0.936 vs. 0.817, p = 0.027). T2 values moderately positively correlated with ADC (r = 0.675, p < 0.001). In conclusion, quantitative motion-robust radial T2 mapping is feasible for characterizing solid renal masses and could provide additional value for multiparametric imaging in predicting WHO/ISUP grade and pT stage of ccRCC.

Age and sex-related differences in T1 and T2 mapping. 1.5 magnetic resonance referent values

Introduction: Parametric mapping is a non-invasive method to quantify tissue changes in the myocardium by measuring T1, T2 and T2* relaxation times and extracellular volume, requiring a pre-established range of normal values. Purpose: To establish reference values for native T1 and T2 myocardial relaxation times in healthy subjects on 1.5 T magnetic resonance imaging and to assess changes in their values according to left ventricular segments, age, sex, heart rate, and myocardial thickness. Material and Methods: A prospective 1.5 T magnetic resonance imaging study was performed with the voluntary participation of 50 healthy individuals in different age groups. Image analysis was performed by a radiologist with 5 years of experience in the field of CMRT and further coordinated with a radiologist with more than 20 years of expe-rience in the field. Siemens ARGUS integrated software was used to calculate the volumes and function of both cameras. Global and segmental T1 and T2 values were measured in the shortaxis midlevel section by manually delineating the region of interest. Myocardial thickness of the mid septum was measured for each patient. Results: The distribution of volunteers was 25 men and 25 women. Significantly higher global T1 values were observed in women (1027.7 &amp;plusmn; 25.4 ms) compared to men (992.9 &amp;plusmn; 24.4 ms), at p &lt; 0.001. The same correlation was observed in individual segments, with a significant difference between genders. Examination of the correlation between T1 and other parameters demonstrated a negative linear relationship only with myocardial thickness. Global T2 in women (48.6 &amp;plusmn; 2.49 ms) was also significantly higher than in men (44.6 &amp;plusmn; 2.06 ms), with an observed difference of 3.95, p &lt; 0.001. Global T2 showed a very strong negative correlation with myocardial thickness (r = -0.769; p &lt; 0.001). There was no sig-nificant correlation between T2 times and heart rate and age of patients. Conclusion: A statistically significant difference in native T1 and T2 values by sex was demonstrated. The use of sex-specific reference values to distinguish healthy from pathologically affected myocardium is recommended.

Multiparametric MRI Scoring System of the Pancreas for the Diagnosis of Chronic Pancreatitis.

Ductal features alone may not offer high diagnostic sensitivity or most accurate disease severity of chronic pancreatitis (CP). Diagnose CP based on multiparametric MRI and MRCP features. Prospective. Between February 2019 and May 2021, 46 control (23 males, 49.3 ± 14.1 years), 45 suspected (20 males, 48.7 ± 12.5 years), and 46 definite (20 males, 53.7 ± 14.6 years) CP patients were enrolled at seven hospitals enrolled in the MINIMAP study. CP classification was based on imaging findings and clinical presentation. 1.5 T. T1-weighted (T1W) spoiled gradient echo, T1 map with variable flip angle, dual-echo Dixon, secretin-enhanced MRCP before and after secretin infusion. Dual-echo fat fraction (FF), T1 relaxation time, extracellular volume (ECV), T1 signal intensity ratio of the pancreas to the spleen (T1 score), arterial-to-venous enhancement ratio (AVR), pancreatic tail diameter (PTD), pancreas volume, late gadolinium enhancement, pancreatic ductal elasticity (PDE), and duodenal filling grade of secretin-enhanced MRCP were measured. Logistic regression analysis generated CP-MRI and secretin-enhanced CP-SMRI scores. Receiver operating characteristics analysis was used to differentiate definite CP from control. Interobserver agreement was assessed using Lin's concordance correlation coefficient. Compared to control, definite CP cohort showed significantly higher dual-echo FF (7% vs. 11%), lower AVR (1.35 vs. 0.85), smaller PTD (2.5 cm vs. 1.95 cm), higher ECV (28% vs. 38%), and higher incidence of PDE loss (6.5% vs. 50%). With the cut-off of >2.5 CP-MRI score (dual-echo FF, AVR, and PTD) and CP-SMRI score (dual-echo FF, AVR, PTD, and PDE) had cross-validated area under the curves of 0.84 (sensitivity 87%, specificity 68%) and 0.86 (sensitivity 89%, specificity 67%), respectively. Interobserver agreement for both CP-MRI and CP-SMRI scores was 0.74. The CP-MRI and CP-SMRI scores yielded acceptable performance and interobserver agreement for the diagnosis of CP. 1 TECHNICAL EFFICACY: Stage 2.

Quantitative muscle MRI in sporadic inclusion body myositis (sIBM): A prospective cohort study.

Sporadic inclusion body myositis (sIBM) is the predominant idiopathic inflammatory myopathy (IIM) in older people. Limitations of classical clinical assessments have been discussed as possible explanations for failed clinical trials, underlining the need for more sensitive outcome measures. Quantitative muscle MRI (qMRI) is a promising candidate for evaluating and monitoring sIBM. Longitudinal assessment of qMRI in sIBM patients. We evaluated fifteen lower extremity muscles of 12 sIBM patients (5 females, mean age 69.6, BMI 27.8) and 12 healthy age- and gender-matched controls. Seven patients and matched controls underwent a follow-up evaluation after one year. Clinical assessment included testing for muscle strength with Quick Motor Function Measure (QMFM), IBM functional rating scale (IBM-FRS), and gait analysis (6-minute walking distance). 3T-MRI scans of the lower extremities were performed, including a Dixon-based sequence, T2 mapping and Diffusion Tensor Imaging. The qMRI-values fat-fraction (FF), water T2 relaxation time (wT2), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (λ1), and radial diffusivity (RD) were analysed. Compared to healthy controls, significant differences for all qMRI parameters averaged over all muscles were found in sIBM using a MANOVA (p < 0.001). In low-fat muscles (FF < 10%), a significant increase of wT2 and FA with an accompanying decrease of MD, λ1, and RD was observed (p≤0.020). The highest correlation with clinical assessments was found for wT2 values in thigh muscles (r≤-0.634). Significant changes of FF (+3.0%), wT2 (+0.6 ms), MD (-0.04 10-3mm2/s), λ1 (-0.05 10-3mm2/s), and RD (-0.03 10-3mm2/s) were observed in the longitudinal evaluation of sIBM patients (p≤0.001). FA showed no significant change (p = 0.242). qMRI metrics correlate with clinical findings and can reflect different ongoing pathophysiological mechanisms. While wT2 is an emerging marker of disease activity, the role of diffusion metrics, possibly reflecting changes in fibre size and intracellular deposits, remains subject to further investigations.

Prognostic validity of coronary flow reserve (CFR)-derived mapping-stress MRI in the risk stratification of suspected or known CAD patients

PurposeAim of our study is to evaluate the prognostic value of T1 stress mapping in suspected or known- CAD patients.Materials and methodsIn this retrospective study, there were 34 patients with known CAD. Mean follow-up time was 30.9 months (95% CI 29.49–32.31). All eligible participants were re-called for an on-site interview and we evaluated Primary endpoints like all Major Adverse Cardiac Events (MACE) and Secondary endpoints (arrhythmias and all cardiac causes of clinical worsening).ResultsOur general population of patients was split into responders and nonresponders based on T1 Mapping response. The T1 values were not statistically significant when compared based on collected MACE; however, when compared to secondary outcomes, there were significant differences in non-responders patients (p-value 0.001).ConclusionThe microcirculation defect can be identified more effectively and accurately with T1 mapping than conventional qualitative evaluation. T1 mapping assumes a prognostic and therapeutic significance in stratifying the risk of patients with microvascular angina who have shown secondary outcomes.

T2 mapping post acute myocardial infarction: a novel technique in assessing myocardial edema

ObjectiveCardiovascular magnetic resonance (CMR) is considered the gold standard imaging modality for assessing myocardial infarction lesions, offering precise myocardial tissue characterization. Elevated transverse relaxation time (T2) serves as a specific indicator of increased myocardial water content, thus becoming a valuable index for myocardial edema. However, conventional T2-weighted CMR sequence exhibits several limitations, primarily providing qualitative information. In contrast, recently developed quantitative T2 mapping techniques overcome these limitations, enabling a more reliable assessment of myocardial edema. These techniques offer the advantage of diagnosing and monitoring myocardial injury without the necessity of contrast agents. Our study aims to add to a growing literature demonstrating the efficacy of quantitative T2 mapping technique to detect and quantify regions of myocardial edema post-myocardial infarction.ResultNative T1 and T2 mapping accurately identified myocardial edema in all patients enrolled in the study. Notably, native T1 and T2 values exhibited a significant elevation in the infarcted myocardium compared to the remote myocardium (for T1: 1295.50 ± 87.65 vs. 1074.95 ± 92.86 ms, respectively; and for T2: 74.63 ± 6.51 vs. 52.53 ± 6.26 ms, respectively; p < 0.0001 for both). Microvascular obstruction was observed in 12 out of 20 patients, affecting one or more myocardial segments within the infarct areas. Among this subgroup, regions with a microvascular obstruction within the infarct zone displayed lower T1 and T2 values compared to areas of infarction without microvascular obstruction (for T1: 1115.05 ± 64.70 vs. 1295.50 ± 87.65 ms, respectively; and for T2: 53.65 ± 3.56 vs. 74.63 ± 6.51 ms, respectively; p < 0.0001 for both). Additionally, we provided reference values for myocardial T1 and T2 specific to our facility’s 1.5 Tesla CMR system, applicable to both infarct and remote myocardium.ConclusionParametric T1 and T2 mapping techniques can detect and quantify myocardial edema resulting from myocardial infarction. The presence of microvascular obstruction that results from revascularization injury affects both T1 and T2 values. This information can be used and has broad clinical implications for diagnosis and guiding or monitoring the treatment of myocardial infarction.

Magnetic Resonance Imaging Biomarkers of Muscle.

This review is focused on the current status of quantitative MRI (qMRI) of skeletal muscle. The first section covers the techniques of qMRI in muscle with the focus on each quantitative parameter, the corresponding imaging sequence, discussion of the relation of the measured parameter to underlying physiology/pathophysiology, the image processing and analysis approaches, and studies on normal subjects. We cover the more established parametric mapping from T1-weighted imaging for morphometrics including image segmentation, proton density fat fraction, T2 mapping, and diffusion tensor imaging to emerging qMRI features such as magnetization transfer including ultralow TE imaging for macromolecular fraction, and strain mapping. The second section is a summary of current clinical applications of qMRI of muscle; the intent is to demonstrate the utility of qMRI in different disease states of the muscle rather than a complete comprehensive survey.

NT-pro-BNP Level is Related to Left Ventricular Remodeling in Patients With Primary Aldosteronism.

To assess the relationship between the left ventricular remodeling parameters of cardiac magnetic resonance and NT-pro-BNP in patients with primary aldosteronism (PA). Seventy-four PA and 39 essential hypertension patients were prospectively recruited and underwent cardiac magnetic resonance. Plasma NT-pro-BNP was measured before patients underwent cardiac magnetic resonance. Left ventricular remodeling parameters were defined as left ventricular function parameters, T1 mapping parameters, and strain parameters. Differences in continuous variables between two groups were analyzed using Student's t-test or Mann-Whitney U test. Differences in categorical variables between two groups were analyzed by chi-squared test. Spearman's correlation and linear regression were used to analyze the relationships between left ventricular remodeling parameters and plasma NT-Pro-BNP level. P<0.05 was considered as statistically significant. Patients with PA demonstrated higher NT-pro-BNP [86.0 (49.5, 145.5) vs. 45.0 (28.5, 73.5) pg/mL, P=0.001] and Native T1 (1227±41 vs. 1206±43 ms, P=0.015) level than essential hypertension patients. Compared to patients with normal NT-pro-BNP levels, those with abnormal levels demonstrated different left ventricular remodeling parameters. NT-pro-BNP level was independently related to native T1 (β=0.316, P=0.006), extracellular volume (β=0.419, P<0.001), short-axis global circumferential strain (β=0.429, P<0.001), four-chamber global longitudinal strain (β=0.332, P=0.002), and four-chamber global radial strain (β=-0.334, P=0.004) in patients after adjusting for baseline characteristics. NT-pro-BNP level was related to left ventricular remodeling parameters derived from cardiac magnetic resonance in patients with PA. This result implies that clinicians should pay attention to NT-pro-BNP assessment in patients with PA in routine clinical assessment.

Evaluation of Myocarditis with a Free-breathing 3D Isotropic Whole-Heart Joint T1 and T2 Mapping Sequence

BackgroundThe diagnosis of myocarditis by CMR requires the use of T2 and T1 weighted imaging, ideally incorporating parametric mapping. Current 2D mapping sequences are acquired sequentially and involve multiple breath-holds resulting in prolonged scan times and anisotropic image resolution. We developed an isotropic free-breathing 3D whole-heart sequence which allows simultaneous T1 and T2 mapping and validated it in patients with suspected acute myocarditis. MethodsEighteen healthy volunteers and 28 patients with suspected myocarditis underwent conventional 2D T1 and T2 mapping with whole heart coverage and 3D joint T1/T2 mapping on a 1.5T scanner. Acquisition time, image quality, and diagnostic performance were compared. Qualitative analysis was performed using a 4-point Likert scale. Bland-Altman plots were used to assess the quantitative agreement between 2D and 3D sequences. ResultsThe 3D T1/T2 sequence was acquired in 8mins 26s under free breathing, whereas 2D T1 and T2 sequences were acquired with breath holds in 11mins 44s (p=0.0001). All 2D images were diagnostic. For 3D images, 89% of T1 and 96% of T2 images were diagnostic with no significant difference in the proportion of diagnostic images for the 3D and 2D T1 (p=0.2482) and T2 maps (p=1.0000). Systematic bias in T1 was noted with biases of 102ms, 115ms, and 152ms for basal-apical segments, with a larger bias for higher T1 values. Good agreement between T2 values for 3D and 2D techniques was found (bias of 1.8ms, 3.9ms, and 3.6ms for basal-apical segments). The sensitivity and specificity of the 3D sequence for diagnosing acute myocarditis was 74% (95% confidence interval [CI] 49-91%) and 83% (36-100%) respectively, with an estimated c-statistic (95% CI) of 0.85 (0.79-0.91) and no statistically significant difference between the 2D and 3D sequences for the detection of acute myocarditis for T1 (p=0.2207) or T2 (p=1.0000). ConclusionFree-breathing whole heart 3D joint T1/T2 mapping was comparable to 2D mapping sequences with respect to diagnostic performance, but with the added advantages of free-breathing, and shorter scan times. Further work is required to address the bias noted at high T1 values, but this did not significantly impact on diagnostic accuracy.

Magnetic resonance (MR) evaluation of deep venous thrombosis of 338 discharged viral pneumonia patients.

Viral pneumonia (VP) often leads to the development of deep vein thrombosis (DVT) in hospitalized patients. The aim of the study was to investigate the incidence of DVT in discharged patients with VP, and whether new and old DVT differ in transverse relaxation time. In this prospective cohort study in Wuhan, China, 338 consecutive discharged VP patients from February 2021 to March 2023 who underwent T2 weighted Sampling Perfection with Application Optimized Contrast Evolution (SPACE) were recruited to detect DVT. T2 mapping and T2* mapping were performed for the patients with DVT detected by magnetic resonance imaging (MRI). The minimum, maximum, mean of T2 time and T2* time of DVT were recorded as T2min, T2max, T2mean, T2*min, T2*max, and T2*mean, respectively. Clinical data and laboratory findings were compared between new and old DVT cases, which were defined based on the examination results before and after discharge. A Mann-Whitney test was used to compare transverse relaxation time parameters between new and old DVT. Twelve percent of VP patients (40/338) developed new DVT after discharge. Thirty-three out of 104 DVTs did not resolve after discharge. Compared with patients with new DVT, patients with old DVT were older (67 vs. 59 years, P=0.003); and had a higher proportion of bedridden time >72 hours (72.7% vs. 37.0%, P<0.001). Patients with old DVT had a lower lymphocyte count (0.67×109/L vs. 0.97×109/L, P=0.01), higher C-reactive protein (59 vs. 35 mg/L, P=0.019), and higher levels of D-dimer (6.7 vs. 0.9 µg/mL, P<0.001) than patients with new DVT. Patients with old DVT received more invasive mechanical ventilation (30.3% vs. 7.4%, P<0.001) and had a higher proportion of acute respiratory distress syndrome (75.8% vs. 51.9%, P<0.001), and a higher proportion of cardiac injury (39.4% vs. 14.8%, P=0.033) than patients with new DVT. T2min, T2max, T2mean, and T2*max of new DVT were significantly greater than old DVT (17.6±10.4 vs. 13.2±5.9 ms, 94.9±44.9 vs. 42.3±23.6 ms, 46.8±24.0 vs. 25.0±12.6 ms, 22.5±12.4 vs. 10.7±3.5 ms, P<0.05 for all). There was no significant difference in T2*min or T2*mean between new and old DVT (3.2±0.4 vs. 3.1±0.4 ms, 8.2±4.9 vs. 5.5±1.5 ms, P>0.05 for both). T2 weighted SPACE magnetic resonance (MR) is valuable in the follow-up of thrombosis of discharged VP patients. T2 mapping distinguishes between new and old DVT.

Quantitative assessment of gadolinium deposition in dentate nuclei with MR fingerprinting

Gadolinium deposition in the dentate nucleus (DN) has been evaluated by T1-weighted imaging (T1WI) and T1 (R1) mapping, but not MR fingerprinting (MRF). This study investigated associations between T1 and T2 values of DN and gadolinium-based contrast agents (GBCAs) using 2-dimensional MRF. This study included 101 patients. Region of interest analysis was performed for T1 and T2 values of DN on MRF (T1-MRF, T2-MRF) and T1-weighted images (T1WI ratio). T1 and T2 ratios compared to normal cerebellar white matter (T1-MRF ratio, T2-MRF ratio) were calculated. The type of previous GBCA was confirmed in 79 patients, and linear regressions were performed between T1, T2 values and number of GBCAs. Good correlations were observed between T1-MRF and T1WI ratio (ρ=-0.69, P<0.001) and between T1-MRF ratio and T1WI ratio (ρ=-0.76, P<0.001). Mild correlations were observed between T2-MRF and T1WI ratio (ρ=-0.32, P<0.001) and between T2-MRF ratio and T1WI ratio (ρ=-0.44, P<0.001). The number of linear-type GBCAs was associated with T1-MRF (β=-0.62, P<0.001) and T1-MRF ratio (β=-0.54, P<0.001) in univariate linear regression analyses, and with T1-MRF (β=-0.61, P<0.001) and T1-MRF ratio (β=-0.53, P<0.001) in multivariate analysis. The number of linear-type GBCAs was associated with T2-MRF (β=-0.30, P<0.001) and T2-MRF ratio (β=-0.29, P<0.001) in univariate analyses, and with T2-MRF (β=-0.31, P<0.001) and T2-MRF ratio (β=-0.32, P<0.001) in multivariate analyses. No associations were observed between number of macrocyclic GBCAs and T1-MRF (ratio) or T2-MRF (ratio). The number of linear-type GBCA administrations was associated with lower T1 and T2 values (ratios) in DN.

Decreases in cT1 and liver fat content reflect treatment-induced histological improvements in MASH

MRI biomarkers of liver disease are robust and reproducible alternatives to liver biopsy. Emerging data suggest that absolute reduction in iron corrected T1 (cT1) of ≥ 80 ms and relative reduction in liver fat content of 30% reflect histological improvement. We aimed to validate the associations of changes to these noninvasive biomarkers with histological improvement, specifically the resolution of steatohepatitis. A retrospective analysis of participants from three interventional clinical trials who underwent multiparametric MRI to measure liver cT1 and liver fat content (LFC) (LiverMultiScan) alongside biopsies at baseline and end of study. Responders were defined as those achieving resolution of steatohepatitis with no worsening in fibrosis. Differences in the magnitude of change in cT1 and LFC between responders and non-responders was assessed. Individual patient data from 150 participants were included. There was a significant decrease in liver cT1 (-119 ms vs. -49 ms) and liver fat content (-65% vs. -29%) in responders compared to non-responders (P < .001) respectively. The diagnostic accuracy to identify responders was 0.72 (AUC) for both. The Youden's index for cT1 to separate responders from non-responders was -82 ms and for liver fat was a 58% relative reduction. Those achieving a ≥ 80 ms reduction in cT1 were 5-times more likely to achieve histological response (sens 0.68; spec 0.70). Those achieving a 30% relative reduction in liver fat were ∼4 times more likely to achieve a histological response (sens 0.77; spec 0.53). These results, from three combined drug trials, demonstrate that changes in multiparametric MRI markers of liver health (cT1 and PDFF) can predict histological response for steatohepatitis following therapeutic intervention. There is great interest in identifying suitable biomarkers that can be used to replace liver biopsy, or to identify those patients who would benefit from one, in both the clinical management of MASH and in drug development. We investigated the utility of two MRI-derived non-invasive tests, iron corrected T1 mapping (cT1) and liver fat content from proton density fat fraction (PDFF), to predict histological improvement in patients who had undergone experimental treatment for MASH. Using data from 150 people who participated in one of three clinical trials, we observed that a reduction in cT1 by over 80 ms and a relative reduction in PDFF of over 58% were the optimal thresholds for change that predicted resolution of steatohepatitis. PDFF as a marker of liver fat, and cT1 as a specific measure of liver disease activity, are both effective at identifying those who are likely responding to drug interventions and experiencing improvements in overall liver health. NCT02443116, NCT03976401, NCT03551522.

Practice Patterns of Cardiovascular Magnetic Resonance Use in the Diagnosis of Pediatric Myocarditis: A Survey-Based Study

BackgroundCardiovascular magnetic resonance (CMR) is used to diagnose myocarditis in adults and children based on the original Lake Louise Criteria (LLC) and more recently the revised LLC. The major change included in the revised LLC was the incorporation of parametric mapping, which significantly increases the sensitivity and specificity of diagnosis. Subsequently, scientific statements have recommended the use of parametric mapping in the diagnosis of myocarditis in children. However, there are some challenges to parametric mapping that are unique to the pediatric population. Our goal is to characterize clinical CMR and parametric mapping practice patterns for diagnosis of myocarditis in pediatric centers. MethodsThe Cardiovascular Magnetic Resonance Evaluation in Return to Athletes for Myocarditis in COVID-19 and Immunization Consortium created a REDCap survey to evaluate clinical practice patterns for diagnosis of myocarditis in pediatrics. This survey was distributed to the Society for Cardiovascular Magnetic Resonance community. Results59 responses from 51 centers were received, with only one response from each center being utilized. Only 35% of centers (37% of North America, 31% of international) reported using CMR routinely in all patients with a suspicion for myocarditis. Diagnostic uncertainty was noted as the most important reason for CMR, while cost was noted as the least important consideration. The majority of centers reported using the revised LLC (37/51, 72%) compared to original LLC (7/51, 14%) or a hybrid criteria (6/51, 12%). When looking at the use of parametric mapping, only 5/47 (11%) for T1 mapping and 11/49 (22%) for T2 mapping reported having scanner-specific pediatric normative data. ConclusionRoutine CMR imaging for diagnosis of myocarditis in pediatrics is infrequently performed at surveyed centers despite the focus on a group of non-invasive cardiac imagers. While the majority reported using parametric mapping, few centers reporting having pediatric scanner-specific normative data. This highlights an important gap in the utilization of CMR that may aid in the diagnosis of myocardial disease.

No differences in native T1 of the renal cortex between Fabry disease patients and healthy subjects in cardiac dedicated native T1 maps

BackgroundFabry disease (FD) is an X-linked inherited lysosomal storage disease that is caused by deficient activity of the enzyme alpha-galactosidase A. Cardiovascular magnetic resonance (CMR) imaging can detect cardiac sphingolipid accumulation using native T1 mapping. The kidneys are often visible in cardiac CMR native T1 maps, however it is currently unknown if the maps can be used to detect sphingolipid accumulation in the kidneys of FD patients. Therefore, the aim of this study was to evaluate if cardiac dedicated native T1 maps can be used to detect sphingolipid accumulation in the kidneys. MethodsFD patients (n=18, 41 ± 10 years, 44% male) and healthy subjects (n=38, 41 ± 16 years, 47% male) were retrospectively enrolled. Native T1 maps were acquired at 1.5T (MAGNETOM Aera) using MOLLI research sequences. Native T1 values were measured by manually delineating regions of interest (ROI) in the renal cortex, renal medulla, heart, spleen, blood, and liver. Endo- and epicardial borders were delineated in the myocardium and averaged across all slices. Blood ROIs were placed in the left-ventricular blood pool in the midventricular slice. ResultsThere were no differences in native T1 between the FD patients and the healthy subjects in the renal cortex (1034±88 ms vs 1056±59 ms, p=0.29), blood (1614±111 ms vs 1576 ± 100 ms, p=0.22), spleen (1143±45 ms vs 1132±70 ms, p=0.54) or liver (568±49 ms vs 557±47 ms, p=0.41). Native T1 was lower in the hearts of the FD patients compared to healthy subjects (951±79 vs 1006±38, p<0.01), and higher in the renal medulla (1635±144 vs 1514±81, p<0.01). The results were similar when stratified for sex. ConclusionCompared to healthy subjects, patients with FD and cardiac involvement had no differences in native T1 of the renal cortex. FD patients had higher native T1 in the renal medulla, which is not totally explained by differences in blood native T1 but may reflect a hyperfiltration state in the development of renal failure. The findings suggest that sphingolipid accumulation in the renal cortex in FD patients could not be detected with cardiac dedicated research native T1 maps.

Association of epicardial adipose tissue on magnetic resonance imaging with cardiovascular outcomes: Quality over quantity?

Epicardial adipose tissue (EAT) quantity is associated with poor cardiovascular outcomes. However, the quality of EAT may be of incremental prognostic value. Cardiac magnetic resonance (CMR) is the gold standard for tissue characterization but has never been applied for EAT quality assessment. We aimed to investigate EAT quality measured on CMR T1 mapping as a predictor of poor outcomes in an all-comer cohort. We investigated the association of EAT area and EAT T1 times (EAT-T1) with a composite endpoint of nonfatal myocardial infarction, heart failure hospitalization, and all-cause death. A total of 966 participants were included (47.2% female; mean age: 58.4 years) in this prospective observational CMR registry. Mean EAT area and EAT-T1 were 7.3 cm2 and 268 ms, respectively. On linear regression, EAT-T1 was not associated with markers of obesity, dyslipidemia, or comorbidities such as diabetes (p > 0.05 for all). During a follow-up of 57.7 months, a total of 280 (29.0%) events occurred. EAT-T1 was independently associated (adjusted hazard ratio per SD: 1.202; 95% CI: 1.022-1.413; p = 0.026) with the composite endpoint when adjusted for established clinical risk. EAT quality (as assessed via CMR T1 times), but not EAT quantity, is independently associated with a composite endpoint of nonfatal myocardial infarction, heart failure hospitalization, and all-cause death.

External Focus of Attention Reduces Cartilage Load During Drop Landings.

The aim of the present study was to examine the effects of attentional focus instructions on acute changes in the transverse relaxation time (T2) of the femorotibial cartilage and in cartilage volume during repeated drop-jump landings. Ten healthy females (Mage = 20.4 ± 0.8 years) performed a drop landing task from a 50 cm high box over the course of 3 days (50 repetitions each day) across three attentional focus conditions: external focus (EF: focus on landing as soft as possible), internal focus (IF: focus on bending your knees when you land), and control (CON: no-focus instruction), which was counterbalanced across focus conditions. T2 mapping and the volume of femorotibial cartilage were determined from magnetic resonance imaging scans at 1.5 T for the dominant knee before and after completing the drop landings in each attentional focus condition per day. Results indicated a smaller change in cartilage T2 relaxation time and volumetry in the central load-bearing lateral cartilage under the EF, compared to IF and CON. Moreover, the change in T2 and cartilage volume was greater for lateral tibial cartilage as compared to femoral cartilage and was independent of attentional focus instructions. No significant acute quantitative changes were observed in the medial compartment. The peak vertical ground reaction force was found to be the lowest under the EF, compared to IF and CON. These findings suggest that external focus of attention may reduce cartilage load, potentially aiding in the control or management of cartilage injuries during landing in female athletes.

692: T1 & T2 mapping on a Unity MRL in a clinically feasible timeframe

692: T1 & T2 mapping on a Unity MRL in a clinically feasible timeframe

Rationale and design of RESILIENCE: A prospective randomized clinical trial evaluating remote ischaemic conditioning for the prevention of anthracycline cardiotoxicity.

There is a lack of therapies able to prevent anthracycline cardiotoxicity (AC). Remote ischaemic conditioning (RIC) has shown beneficial effects in preclinical models of AC. REmote iSchemic condItioning in Lymphoma PatIents REceiving ANthraCyclinEs (RESILIENCE) is a multinational, prospective, phase II, double-blind, sham-controlled, randomized clinical trial that evaluates the efficacy and safety of RIC in lymphoma patients receiving anthracyclines. Patients scheduled to undergo ≥5 chemotherapy cycles including anthracyclines and with ≥1 AC-associated risk factors will be randomized to weekly RIC or sham throughout the chemotherapy period. Patients will undergo three multiparametric cardiac magnetic resonance (CMR) studies, at baseline, after the third cycle (intermediate CMR), and 2 months after the end of chemotherapy. Thereafter, patients will be followed up for clinical events over an anticipated median of ≥24 months. The primary endpoint is the absolute change from baseline in CMR-based left ventricular ejection fraction (LVEF). The main secondary outcome is the incidence of AC events, defined as (1) a drop in CMR-based LVEF of ≥10 absolute points, or (2) a drop in CMR-based LVEF of ≥5 and <10 absolute points to a value <50%. Intermediate CMR will test the ability of T2 mapping to predict AC versus classical markers (left ventricular strain and cardiac injury biomarkers). A novel CMR sequence allowing ultrafast cine acquisition will be validated in this vulnerable population. The RESILIENCE trial will test RIC (a novel non-invasive intervention to prevent AC) in a cohort of high-risk patients. The trial will also test candidate markers for their capacity to predict AC and will validate a novel CMR sequence reducing acquisition time in a vulnerable population.

Imaging for the diagnosis of acute myocarditis: can artificial intelligence improve diagnostic performance?

Myocarditis is a cardiovascular disease characterised by inflammation of the heart muscle which can lead to heart failure. There is heterogeneity in the mode of presentation, underlying aetiologies, and clinical outcome with impact on a wide range of age groups which lead to diagnostic challenges. Cardiovascular magnetic resonance (CMR) is the preferred imaging modality in the diagnostic work-up of those with acute myocarditis. There is a need for systematic analytical approaches to improve diagnosis. Artificial intelligence (AI) and machine learning (ML) are increasingly used in CMR and has been shown to match human diagnostic performance in multiple disease categories. In this review article, we will describe the role of CMR in the diagnosis of acute myocarditis followed by a literature review on the applications of AI and ML to diagnose acute myocarditis. Only a few papers were identified with limitations in cases and control size and a lack of detail regarding cohort characteristics in addition to the absence of relevant cardiovascular disease controls. Furthermore, often CMR datasets did not include contemporary tissue characterisation parameters such as T1 and T2 mapping techniques, which are central to the diagnosis of acute myocarditis. Future work may include the use of explainability tools to enhance our confidence and understanding of the machine learning models with large, better characterised cohorts and clinical context improving the diagnosis of acute myocarditis.