Epidemiology, diagnosis, and management of cardiac amyloidosis.

Cardiac amyloidosis (CA) is an infiltrative restrictive cardiomyopathy caused by the deposition of amyloid fibrils in the myocardium. It manifests in two primary subtypes: transthyretin cardiac amyloidosis (ATTR) and immunoglobulin light chain cardiac amyloidosis (AL). ATTR is further classified into wild-type and hereditary based on transthyretin gene mutation. Advances in diagnostics and therapeutics have transformed CA from a rare and untreatable condition to a more prevalent and manageable disease. Noninvasive diagnostic tools such as electrocardiography, echocardiography, and cardiac magnetic resonance can raise suspicion for CA; bone scintigraphy can non-invasively confirm ATTR, while AL necessitates histological confirmation. The severity of ATTR and AL can be assessed through serum biomarker-based staging. Treatment approaches differ, ranging from silencing or stabilizing transthyretin and degrading amyloid fibrils in ATTR to employing anti-plasma cell therapies and autologous stem cell transplantation in AL.

Future Horizons: The Potential Role of Artificial Intelligence in Cardiology.

Cardiovascular diseases (CVDs) are the leading cause of premature death and disability globally, leading to significant increases in healthcare costs and economic strains. Artificial intelligence (AI) is emerging as a crucial technology in this context, promising to have a significant impact on the management of CVDs. A wide range of methods can be used to develop effective models for medical applications, encompassing everything from predicting and diagnosing diseases to determining the most suitable treatment for individual patients. This literature review synthesizes findings from multiple studies that apply AI technologies such as machine learning algorithms and neural networks to electrocardiograms, echocardiography, coronary angiography, computed tomography, and cardiac magnetic resonance imaging. A narrative review of 127 articles identified 31 papers that were directly relevant to the research, encompassing a broad spectrum of AI applications in cardiology. These applications included AI models for ECG, echocardiography, coronary angiography, computed tomography, and cardiac MRI aimed at diagnosing various cardiovascular diseases such as coronary artery disease, hypertrophic cardiomyopathy, arrhythmias, pulmonary embolism, and valvulopathies. The papers also explored new methods for cardiovascular risk assessment, automated measurements, and optimizing treatment strategies, demonstrating the benefits of AI technologies in cardiology. In conclusion, the integration of artificial intelligence (AI) in cardiology promises substantial advancements in diagnosing and treating cardiovascular diseases.

Wall motion assessment by feature tracking in pediatric patients with coronary anomalies undergoing dobutamine stress CMR.

Background: Left ventricular (LV) wall motion assessment is an important adjunct in addition to perfusion defects in assessing ischemic changes. This study aims to investigate the feasibility and utility of performing feature tracking (FT) in pediatric patients with coronary anomalies undergoing dobutamine stress CMR to assess wall motion abnormalities (WMA) and perfusion defects. Method: This is a retrospective study where 10 patients with an inducible first-pass perfusion (FPP) defect and 10 without were selected. Global LV circumferential strain/strain rate (GCS/GCSR) was measured at rest and at peak stress (systole and diastole) using a commercially available feature tracking software. Peak GCS and GCSR were compared to indexed wall motion score (WMSI) between groups with and without FPP defect and in subjects with and without WMA. Results: The median age of patients was 13.5 years (Q1, 11 years; Q3, 15 years). Five subjects had qualitatively WMA at peak stress. A moderate correlation of GCS with WMSI at peak stress (0.48, p = 0.026) and a significant difference between GCS at rest and stress in patients with no inducible WMA (p = 0.007) were seen. No significant difference was noted in GCS between rest and stress in patients with WMA (p = 0.13). There was a larger absolute GCS/GCSR at peak stress in subjects with no inducible FPP defect or WMA. Conclusion: Smaller absolute GCS and a lack of significant change in GCS at peak stress in those with inducible WMA or perfusion defect are suggestive of compromised LV deformation in subjects with inducible WMA. Given these findings, GCS derived from CMR-FT may be used to objectively assess WMA in pediatric patients undergoing stress CMR.

The impact of severe obesity on image quality and ventricular function assessment in echocardiography and cardiac MRI.

This study sought to evaluate the impact of severe obesity on image quality and ventricular function assessment in cardiovascular magnetic resonance (MRI) and trans-thoracic echocardiography (TTE). We studied 100 consecutive patients who underwent clinically indicated cardiac MRI and TTE studies within 12 months between July 2017 and December 2020; 50 (28 females and 22 males; 54.5 ± 18.7 years) with normal body mass index (BMI) (18.5-25 kg/m2) and 50 (21 females and 29 males; 47.2 ± 13.3 years) with severe obesity (BMI ≥ 40 kg/m2). MRI and TTE image quality scores were compared within and across cohorts using a linear mixed model. Categorical left (LVF) and right (RVF) ventricular function were compared using Cohens Kappa statistic. Mean BMI for normal weight and obese cohorts were 22.2 ± 1.7 kg/m2 and 50.3 ± 5.9 kg/m2, respectively. Out of a possible 93 points, mean MRI image quality score was 91.5 ± 2.5 for patients with normal BMI, and 88.4 ± 5.5 for patients with severe obesity; least square (LS) mean difference 3.1, p = 0.460. TTE scores were 64.2 ± 13.6 for patients with normal BMI and 46.0 ± 12.9 for patients with severe obesity, LS mean difference 18.2, p < 0.001. Ventricular function agreement between modalities was worse in the obese cohort for both LVF (72% vs 80% agreement; kappa 0.53 vs 0.70, obese vs. normal BMI), and RVF (58% vs 72% agreement, kappa 0.18 vs 0.34, obese vs. normal BMI). Severe obesity had limited impact on cardiac MRI image quality, while obesity significantly degraded TTE image quality and ventricular function agreement with MRI.

Fully automated contrast selection of joint bright- and black-blood late gadolinium enhancement imaging for robust myocardial scar assessment.

PURPOSE: Joint bright- and black-blood MRI techniques provide improved scar localization and contrast. Black-blood contrast is obtained after the visual selection of an optimal inversion time (TI) which often results in uncertainties, inter- and intra-observer variability and increased workload. In this work, we propose an artificial intelligence-based algorithm to enable fully automated TI selection and simplify myocardial scar imaging. METHODS: The proposed algorithm first localizes the left ventricle using a U-Net architecture. The localized left cavity centroid is extracted and a squared region of interest ("focus box") is created around the resulting pixel. The focus box is then propagated on each image and the sum of the pixel intensity inside is computed. The smallest sum corresponds to the image with the lowest intensity signal within the blood pool and healthy myocardium, which will provide an ideal scar-to-blood contrast. The image's corresponding TI is considered optimal. The U-Net was trained to segment the epicardium in 177 patients with binary cross-entropy loss. The algorithm was validated retrospectively in 152 patients, and the agreement between the algorithm and two magnetic resonance (MR) operators' prediction of TI values was calculated using the Fleiss' kappa coefficient. Thirty focus box sizes, ranging from 2.3mm2 to 20.3cm2, were tested. Processing times were measured. RESULTS: The U-Net's Dice score was 93.0 ± 0.1%. The proposed algorithm extracted TI values in 2.7 ± 0.1 s per patient (vs. 16.0 ± 8.5 s for the operator). An agreement between the algorithm's prediction and the MR operators' prediction was found in 137/152 patients (κ= 0.89), for an optimal focus box of size 2.3cm2. CONCLUSION: The proposed fully-automated algorithm has potential of reducing uncertainties, variability, and workload inherent to manual approaches with promise for future clinical implementation for joint bright- and black-blood MRI.

Reproducibility assessment of rapid strains in cardiac MRI: Insights and recommendations for clinical application.

PURPOSE: Studies have shown the incremental value of strain imaging in various cardiac diseases. However, reproducibility and generalizability has remained an issue of concern. To overcome this, simplified algorithms such as rapid atrioventricular strains have been proposed. This multicenter study aimed to assess the reproducibility of rapid strains in a real-world setting and identify potential predictors for higher interobserver variation. METHODS: A total of 4 sites retrospectively identified 80 patients and 80 healthy controls who had undergone cardiac magnetic resonance imaging (CMR) at their respective centers using locally available scanners with respective field strengths and imaging protocols. Strain and volumetric parameters were measured at each site and then independently re-evaluated by a blinded core lab. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to assess inter-observer agreement. In addition, backward multiple linear regression analysis was performed to identify predictors for higher inter-observer variation. RESULTS: There was excellent agreement between sites in feature-tracking and rapid strain values (ICC ≥ 0.96). Bland-Altman plots showed no significant bias. Bi-atrial feature-tracking and rapid strains showed equally excellent agreement (ICC ≥ 0.96) but broader limits of agreement (≤18.0 % vs. ≤3.5 %). Regression analysis showed that higher field strength and lower temporal resolution (>30 ms) independently predicted reduced interobserver agreement for bi-atrial strain parameters (ß = 0.38, p = 0.02 for field strength and ß = 0.34, p = 0.02 for temporal resolution). CONCLUSION: Simplified rapid left ventricular and bi-atrial strain parameters can be reliably applied in a real-world multicenter setting. Due to the results of the regression analysis, a minimum temporal resolution of 30 ms is recommended when assessing atrial deformation.

Assessment of Feasibility and Interscan Variability of Short-time Cardiac MRI for Cardiotoxicity Evaluation in Breast Cancer.

Purpose To investigate the feasibility and interscan variability of short-time cardiac MRI protocol after chemotherapy in individuals with breast cancer. Materials and Methods A total of 13 healthy female controls (mean age, 52.4 years ± 13.2 [SD]) and 85 female participants with breast cancer (mean age, 51.8 years ± 9.9) undergoing chemotherapy prospectively underwent routine breast MRI and short-time cardiac MRI using a 3-T scanner with peripheral pulse gating in the prone position. Interscan, intercoil, and interobserver reproducibility and variability of native T1 and extracellular volume (ECV), as well as ventricular functional parameters, were measured using the intraclass correlation coefficient (ICC), standard error of measurement (SEM), or coefficient of variation (CoV). Results Left ventricular functional parameters had excellent interscan reproducibility (ICC ≥ 0.80). Left ventricular ejection fraction showed low interscan variability in control and chemotherapy participants (SEM, 2.0 and 1.2; CoV, 3.1 and 1.9, respectively). Native T1 showed excellent interscan (ICC, 0.75) and intercoil (ICC, 0.81) reproducibility in the control group and good interscan reproducibility (ICC, 0.72 and 0.73, respectively) in the participants undergoing immediate and remote chemotherapy. Interscan reproducibility for ECV was excellent in the control group and in the remote chemotherapy group (ICC, 0.93 and 0.88, respectively) and fair in the immediate chemotherapy group (ICC, 0.52). In the regional analysis, interscan repeatability and variability of native T1 and ECV were superior in the anteroseptum or inferoseptum than in other segments in the immediate chemotherapy group. Native T1 and ECV had good to excellent interobserver agreement across all groups. Conclusion Short-time cardiac MRI showed excellent results for interscan, intercoil, and interobserver reproducibility and variability for ventricular functional or tissue characterization parameters, suggesting that this modality is feasible for routine surveillance of cardiotoxicity evaluation in individuals with breast cancer. Keywords: Cardiac MRI, Heart, Cardiomyopathy ClinicalTrials.gov registration no. NCT03301389 Supplemental material is available for this article. © RSNA, 2024.

Ethnic differences in cardiac structure and function assessed by MRI in healthy South Asian and White European people: A UK Biobank Study.

BACKGROUND: Echocardiographic studies indicate South Asian people have smaller ventricular volumes, lower mass and more concentric remodelling than White European people, but there are no data using cardiac MRI (CMR). We aimed to compare CMR quantified cardiac structure and function in White European and South Asian people. METHODS: Healthy White European and South Asian participants in the UK Biobank Imaging CMR sub-study were identified by excluding those with a history of cardiovascular disease, hypertension, obesity or diabetes. Ethnic groups were matched by age and sex. Cardiac volumes, mass and feature tracking strain were compared. RESULTS: 121 matched pairs (77 male/44 female, mean age 58 ± 8 years) of South Asian and White European participants were included. South Asian males and females had smaller absolute but not indexed left ventricular (LV) volumes, and smaller absolute and indexed right ventricular volumes, with lower absolute and indexed LV mass and lower LV mass:volume than White European participants. Although there were no differences in ventricular or atrial ejection fractions, LV global longitudinal strain was higher in South Asian females than White European females but not males, and global circumferential strain was higher in both male and South Asian females than White European females. Peak early diastolic strain rates were higher in South Asian versus White European males, but not different between South Asian and White European females. CONCLUSIONS: Contrary to echocardiographic studies, South Asian participants in the UK Biobank study had less concentric remodelling and higher global circumferential strain than White European subjects. These findings emphasise the importance of sex- and ethnic- specific normal ranges for cardiac volumes and function.

Intracardiac shunt assessment using CT coronary angiography.

BACKGROUND: Detection of intracardiac shunts using CT Coronary Angiography (CTCA) is currently based on anatomical demonstration of defects. We assessed a novel technique using a standard CTCA test bolus in detecting shunts independent of anatomical assessment and to provide an estimate of Qp/Qs. METHODS: We retrospectively reviewed 51 CTCAs: twenty-one from patients with known simple left to right intracardiac shunts with contemporaneous functional assessment (using CMR) within 6 months, 20 controls with structurally normal hearts, and 10 patients with shunt repairs. From the dynamic acquisition of a test bolus, we measured mean Hounsfield Units (HU) in various anatomical structures. We created time/density curves from the test bolus data, and calculated disappearance time (DT) from the ascending aorta (deriving a Qp/Qs), peak ascending aortic HU, and mean coefficient of variation of the arterial curves, and compared these with the Qp/Qs from the respective CMR. RESULTS: Patients with intracardiac shunts had significantly higher test bolus derived Qp/Qs compared with both the controls, and the repaired shunt comparator group. There was a very strong agreement between the test bolus derived Qp/Qs, and Qp/Qs as measured by CMR (Intraclass correlation 0.89). Mean bias was 0.032 â€‹± â€‹0.341 (95% limits of agreement -0.64 to 0.70). Interobserver, and intraobserver agreement of the disappearance time was excellent (0.99, 0.99 (reader 1) and 1.00 (reader 2) respectively). CONCLUSION: In this proof-of-concept study, we demonstrate a novel technique to detect, and to estimate severity of left to right intracardiac shunts on routine Cardiac CT.

Assessment of left atrioventricular coupling and left atrial function impairment in diabetes with and without hypertension using CMR feature tracking.

PURPOSE: The study was designed to assess the effect of co-occurrence of diabetes mellitus (DM) and hypertension on the deterioration of left atrioventricular coupling index (LACI) and left atrial (LA) function in comparison to individuals suffering from DM only. METHODS: From December 2015 to June 2022, we consecutively recruited patients with clinically diagnosed DM who underwent cardiac magnetic resonance (CMR) at our hospital. The study comprised a total of 176 patients with DM, who were divided into two groups based on their blood pressure status: 103 with hypertension (DM + HP) and 73 without hypertension (DM-HP). LA reservoir function (reservoir strain (εs), total LA ejection fraction (LAEF)), conduit function (conduit strain (εe), passive LAEF), booster-pump function (booster strain (εa) and active LAEF), LA volume index (LAVI), LV global longitudinal strain (LVGLS), and LACI were evaluated and compared between the two groups. RESULTS: After adjusting for age, sex, body surface area (BSA), and history of current smoking, total LAEF (61.16 ± 14.04 vs. 56.05 ± 12.72, p = 0.013) and active LAEF (43.98 ± 14.33 vs. 38.72 ± 13.51, p = 0.017) were lower, while passive LAEF (33.22 ± 14.11 vs. 31.28 ± 15.01, p = 0.807) remained unchanged in the DM + HP group compared to the DM-HP group. The DM + HP group had decreased εs (41.27 ± 18.89 vs. 33.41 ± 13.94, p = 0.006), εe (23.69 ± 12.96 vs. 18.90 ± 9.90, p = 0.037), εa (17.83 ± 8.09 vs. 14.93 ± 6.63, p = 0.019), and increased LACI (17.40±10.28 vs. 22.72±15.01, p = 0.049) when compared to the DM-HP group. In patients with DM, multivariate analysis revealed significant independent associations between LV GLS and εs (ß=-1.286, p < 0.001), εe (ß=-0.919, p < 0.001), and εa (ß=-0.324, p = 0.036). However, there was no significant association observed between LV GLS and LACI (ß=-0.003, p = 0.075). Additionally, hypertension was found to independently contribute to decreased εa (ß=-2.508, p = 0.027) and increased LACI in individuals with DM (ß = 0.05, p = 0.011). CONCLUSIONS: In DM patients, LV GLS showed a significant association with LA phasic strain. Hypertension was found to exacerbate the decline in LA booster strain and increase LACI in DM patients, indicating potential atrioventricular coupling index alterations.

Simultaneous assessment of vascular distensibility and vessel wall area at coronary, carotid, and aortic level in diabetic patients using CMR: detection of vascular remodeling.

AIMS: No data is available about the significance of cardiovascular magnetic resonance (CMR) derived vascular distensibility (VD) and vessel wall ratio (VWR) for risk stratification in patients with type 2 diabetes mellitus (T2DM). Therefore, this study aimed to investigate the effects of T2DM on VD and VWR using CMR in both central and peripheral territories. METHODS: Thirty-one T2DM-patients and nine controls underwent CMR. Angulation of the aorta, the common carotid, and the coronary arteries was performed to obtain cross-sectional vessel areas. RESULTS: In T2DM the Carotid-VWR and the Aortic-VWR correlated significantly. Mean values of Carotid-VWR and Aortic-VWR were significantly higher in T2DM than in controls. Coronary-VD was significantly lower in T2DM than in controls. No significant difference in Carotid-VD or Aortic-VD in T2DM vs. controls, respectively, could be observed. In a subgroup of thirteen T2DM patients with coronary artery disease (CAD), Coronary-VD was significantly lower and Aortic-VWR was significantly higher compared to T2DM patients without CAD. CONCLUSION: CMR allows a simultaneous evaluation of the structure and function of three important vascular territories to detect vascular remodeling in T2DM.

Role of 3 Tesla Magnetic Resonance Imaging in the Assessment of Infiltrative Cardiomyopathies.

BACKGROUND: The aim of the present study was to assess the role of 3 Tesla (3T) magnetic resonance imaging (MRI) in the assessment of infiltrative cardiomyopathy (ICM). METHODS: Cardiac MRI was performed on a 3T MRI machine for 15 patients who had clinical or echocardiographic signs of infiltrative cardiomyopathy. Each scan was assessed on a set of anatomical and functional parameters. The patterns of left ventricular (LV) late gadolinium enhancement (LGE) were also analyzed. RESULTS: Bi-atrial dilatation was noted in 14 patients, consistent with a restrictive phenotype. All 15 patients had diastolic dysfunction with reduced LV diastolic ventricular filling and prolonged peak filling times. Eleven patients had a decreased peak filling rate. Twelve patients had systolic dysfunction with reduced ejection fraction (EF). Ten patients had contractile dysfunction in the form of global LV hypokinesia. On delayed contrast imaging, four patients showed no abnormal LGE. Two patients showed diffuse subendocardial enhancement. Two patients showed patchy subendocardial enhancement. Six patients showed patchy mid-myocardial enhancement. One patient showed diffuse mid-myocardial enhancement. Three patients showed patchy subepicardial enhancement. Two patients showed patchy transmural enhancement. Three patients showed reversed myocardial nulling. All 15 patients received a provisional diagnosis of infiltrative cardiomyopathy on the basis of cardiac MRI findings. Sarcoidosis was given as a probable cause in four patients, amyloidosis in three patients, an infectious cause in two patients, and drug-induced cardiomyopathy in one patient. In five patients, no obvious cause could be identified. CONCLUSION: Infiltrative cardiomyopathies, although relatively uncommon, pose significant challenges in diagnosis and treatment. Cardiac MRI has become the gold standard for non-invasive diagnosis of all infiltrative cardiomyopathies.

The impact of viability assessment using cardiac MRI and echocardiogram on the outcome of revascularization in patients with multi-vessels coronary artery disease and moderate to severe ischemic cardiomyopathy.

OBJECTIVES: To investigate the influence of viability assessment in the management of patients with ischemic cardiomyopathy (ICM). METHODS: This retrospective cohort study included all patients with ICM with moderate to severely reduced left ventricular ejection fraction (LVEF) who underwent viability assessment using cardiac magnetic resonance imaging (MRI) and echocardiogram as modalities of imaging. In addition, LVEF, modality of choice, and treatment plans were all extracted as main variables from the electronic database. One hundred 6 patients who met the inclusion criteria from December 2014 to December 2019 were included. RESULTS: Posttreatment LVEF improved by 5% in the viable group compared to the nonviable group (p=0.016). Regardless of the treatment received, 6 (8.8%) patients in the viable group died due to cardiac causes after an 18-month follow-up period; in contrast, 7 (18.4%) patients died due to cardiac causes in the nonviable group. However, despite that difference, this was not statistically significant (p=0.153). Medical therapy alone was observed in 32 (84.2%) patients in the nonviable group compared to 32 (47.1%) in the viable group (p<0.001). Although the reduction in hospitalization for cardiac reasons was not statistically significant, the viable arm had 50% fewer hospitalizations than the nonviable arm (p=0.051). CONCLUSION: Patients with viable myocardium had better outcomes in which LVEF significantly improved posttreatment. Additionally, there was a reduction in the number of hospitalizations for cardiac reasons in the viable group compared to the nonviable group, even though the difference was not statistically significant. However, further studies with a larger number of patients are needed to determine a definite conclusion.

Free-breathing pseudo-golden-angle bSSFP cine cardiac MRI for biventricular functional assessment in congenital heart disease.

PURPOSE: To compare standard breath-hold (BH) cine imaging to a radial pseudo-golden-angle free-breathing (FB) technique in congenital heart disease (CHD). METHODS: In this prospective study, short-axis and 4-chamber BH and FB cardiac MRI sequences of 25 participants with CHD acquired at 1.5 Tesla, were quantitatively compared regarding ventricular volumes, function, interventricular septum thickness (IVSD), apparent signal to noise ratio (aSNR), and estimated contrast to noise ratio (eCNR). For qualitative comparison, three image quality criteria (contrast, endocardial edge definition, and artefacts) were rated on a 5-point Likert scale (5: excellent, 1: non-diagnostic). Paired t-Test was used for group comparisons, Bland-Altman analysis for agreement between techniques. Inter-reader agreement was compared using intraclass correlation coefficient. RESULTS: IVSD (BH 7.4 ± 2.1 mm vs FB 7.4 ± 1.9 mm, p =.71), biventricular ejection fraction (left ventricle [LV]: 56.4 ± 10.8% vs 56.1 ± 9.3%, p =.83; right ventricle [RV]: 49.5 ± 8.6% vs 49.7 ± 10.1%, p =.83), and biventricular end diastolic volume (LV: 176.3 ± 63.9 ml vs 173.9 ± 64.9 ml, p =.90; RV: 185.4 ± 63.8 ml vs 189.6 ± 66.6 ml, p =.34) were comparable. Mean measurement time for FB short-axis sequences was 8.1 ± 1.3 compared to 4.4 ± 1.3 min for BH (p <.001). Subjective image quality between sequences was deemed comparable, (4.6 ± 0.6 vs 4.5 ± 0.6, p =.26, for 4-chamber views) with a significant difference regarding short-axis views (4.9 ± 0.3 vs 4.5 ± 0.6, p =.008). aSNR was similar (BH 25.8 ± 11.2 vs FB 22.2 ± 9.5, p =.24), while eCNR was higher for BH (89.1 ± 36.1 vs 68.5 ± 32.1, p =.03). CONCLUSION: FB sequences yielded comparable results to BH regarding image quality, biventricular volumetry, and function, though measurement times were longer. The FB sequence described might be clinically valuable when BHs are insufficiently performed.

Cardiac MRI-Based Assessment of Myocardial Injury in Asymptomatic People Living With Human Immunodeficiency Virus: Correlation With nadir CD4 Count.

BACKGROUND: There are known cardiac manifestations of HIV, but the findings in asymptomatic subjects are still not fully explored. PURPOSE: To evaluate for the presence of subclinical myocardial injury in asymptomatic people living with human immunodeficiency virus (PLWH) by cardiac MRI and to explore the possible association between subclinical myocardial injury and HIV-related clinical characteristics. STUDY TYPE: Cross-sectional. POPULATION: A total of 80 asymptomatic PLWH (age: 53 years [47-56 years]; 90% male) and 50 age- and sex-matched healthy participants. FIELD STRENGTH/SEQUENCE: A 3-T, cine sequence, T1, T2, and T2* mapping. ASSESSMENT: Function analysis was derived from short axis, two-, three-, and four-chamber cine images by feature tracking. Regions of interest were manually selected in the midventricular septum T1, T2, and T2* mapping sequences. PLWH were evaluated for T1 increment (△T1 mapping = native T1 - cutoff values) and HIV-related clinical characteristics, particularly the nadir CD4 count. And PLWH were stratified into two groups according to the cutoff value of native T1: elevated native T1 and normal. STATISTICAL TESTS: T test, Wilcoxon rank-sum test, Chi-square test, Spearman rank correlation, and logistic regression. P <0.05 indicated statistical significance. RESULTS: Asymptomatic PLWH revealed significantly higher native myocardial T1 values (1241 ± 29 msec vs. 1189 ± 21 msec), T2 values (40.7 ± 1.5 msec vs. 37.9 ± 1.4 msec), and lower LVGRS (30.2% ± 6.2% vs. 35.8% ± 6.4%), LVGCS (-18.0% ± 2.5% vs. -19.5% ± 2.0%), and LVGLS (-16.0% ± 3.8% vs. -17.9% ± 2.6%) but showed no difference in T2* values (17.3 msec [16.3-19.1 msec] vs. 18.3 msec [16.5-19.3 msec], P = 0.201). A negative correlation between the native T1 increment in PLWH with subclinical myocardial injury and the nadir CD4 count (u = -0.316). Nadir CD4 count <500 cells/mm3 was associated with higher odds of elevated native T1 myocardial values (odds ratio, 6.12 [95% CI, 1.07-34.91]) in PLWH. DATA CONCLUSION: Subclinical myocardial inflammation and dysfunction were present in asymptomatic PLWH, and a lower nadir CD4 count may be a risk factor for subclinical myocardial injury. EVIDENCE LEVEL: 1. TECHNICAL EFFICACY: Stage 2.

Contrast-enhanced cine MR sequences in the assessment of myocardial hyperemia in acute myocarditis: can they help? A feasibility study.

The study was designed to assess the accuracy of contrast-enhanced balanced steady-state free precession (cine-SSFP) CMR imaging sequences to exhibit myocardial hyperemia in acute myocarditis, which has for a long time been investigated in some centers using early gadolinium enhancement (EGE) sequence. Contrast-enhanced cine-SSFP (CESSFP) sequences were compared to precontrast cine-SSFP sequences to calculate the early cine-contrast enhancement in 36 consecutive patients with acute myocarditis and 36 controls matched for age and gender. Four-chamber views images were obtained in each subject before and after gadolinium injection. Absolute and relative left ventricular myocardial enhancement of the overall myocardium, then separately of the lateral wall and interventricular septum was analyzed in telediastole. Myocarditis patients displayed higher cine-SSFP absolute enhancement than controls (overall left ventricular myocardium 2.38 ± 0.33 vs 1.84 ± 0.31; lateral wall 2.45 ± 0.35 vs 1.83 ± 0.32; and septum 2.26 ± 0.29 vs 1.82 ± 0.29, p < 0.0001 for all). Less significant differences were observed for the relative enhancement (p < 0.05 for all). Using ROC curves, the optimal threshold value of absolute enhancement to diagnose acute myocarditis was 2.05 (sensitivity: 86%; specificity: 81%). Given the simplicity of use, contrast-enhanced cine-SSFP sequences should be used as an additional diagnostic tool to detect hyperemia in acute myocarditis patients.

Assessment of myocardial fibrosis in patients with systemic sclerosis using [68Ga]Ga-FAPI-04-PET-CT.

PURPOSE: Myocardial fibrosis (MF) is a factor of poor prognosis in systemic sclerosis (SSc). Direct in-vivo visualization of fibroblast activation as early readout of MF has not been feasible to date. Here, we characterize 68Gallium-labeled-Fibroblast-Activation-Inhibitor-04 ([68Ga]Ga-FAPI-04)-PET-CT as a diagnostic tool in SSc-related MF. METHODS: In this proof-of-concept trial, six SSc patients with and eight without MF of the EUSTAR cohort Erlangen underwent [68Ga]Ga-FAPI-04-PET-CT and cardiac MRI (cMRI) and clinical and serologic investigations just before baseline and during follow-up between January 2020 and December 2020. Myocardial biopsy was performed as clinically indicated. RESULTS: [68Ga]Ga-FAPI-04 tracer uptake was increased in SSc-related MF with higher uptake in SSc patients with arrhythmias, elevated serum-NT-pro-BNP, and increased late gadolinium enhancement (LGE) in cMRI. Histologically, myocardial biopsies from cMRI- and [68Ga]Ga-FAPI-04-positive regions confirmed the accumulation of FAP+ fibroblasts surrounded by collagen deposits. We observed similar but not equal spatial distributions of [68Ga]Ga-FAPI-04 uptake and quantitative cMRI-based techniques. Using sequential [68Ga]Ga-FAPI-04-PET-CTs, we observed dynamic changes of [68Ga]Ga-FAPI-04 uptake associated with changes in the activity of SSc-related MF, while cMRI parameters remained stable after regression of molecular activity and rather indicated tissue damage. CONCLUSIONS: We present first in-human evidence that [68Ga]Ga-FAPI-04 uptake visualizes fibroblast activation in SSc-related MF and may be a diagnostic option to monitor cardiac fibroblast activity in situ.

Cardiac Assessment in Children with MIS-C: Late Magnetic Resonance Imaging Features.

Multisystem Inflammatory Syndrome (MIS-C) is a new entity that emerges 2-4 weeks after the SARS-CoV-2 infection in children. MIS-C can affect all systems, the most severe of which is cardiac involvement. The duration of the cardiac symptoms is still uncertain and may be persistent or prolonged. The American College of Rheumatology Clinical Guidelines recommends cardiac magnetic resonance imaging (MRI) 2-6 months after the diagnosis of MIS-C in patients presenting with significant transient left ventricular (LV) dysfunction in the acute phase of illness (LV ejection fraction 50%) or persistent LV dysfunction. There are a few studies investigating cardiac MRI findings in MIS-C patients. In this study, we aimed to evaluate cardiac MRI findings, at the earliest 3 months after diagnosis, and compare these findings with the echocardiograms in children with MIS-C. A retrospective study including 34 MIS-C patients was conducted at a tertiary-level University Hospital between June 2020 and July 2021. Centers for Disease Control and Prevention criteria were used in the diagnosis of MIS-C. Cardiac MRI was performed at least 3 months after MIS-C diagnosis. The study included 17 (50%) boys and 17 (50%) girls with a mean age of 9.31 ± 4.72 years. Initial echocardiographic evaluation revealed cardiac abnormality in 13 (38.2) patients; 4 (11.8%) pericardial effusion, 4 (11.8%) left ventricular ejection fraction (LVEF) < 55%, and 5 (14.7%) coronary artery dilatation. Echocardiography showed normal LV systolic function in all patients during follow-up; coronary dilatation persisted in 2 of 5 (40%) patients at the 6th-month visit. Cardiac MRI was performed in 31 (91.2%) patients, and myocardial hyperemia was not detected in any patients (T1 relaxation time was < 1044 ms in all children). However, 9 (29%) patients' MRI showed isolated elevated T2 levels, and 19 (61.3%) revealed at least one of the following findings: pericardial effusion, right ventricular dysfunction, or LVEF abnormality. In patients with MIS-C, a high rate of cardiac involvement, particularly pericardial effusion was determined by cardiac MRI performed at the earliest 2-6 months after diagnosis. Even if echocardiography does not reveal any abnormality in the initial phase, cardiac MRI should be suggested in MIS-C patients in the late period. This is the first study reporting cardiac MRI findings in the late period of MIS-C patients.

Texture analysis of native T1 images as a novel method for non-invasive assessment of heart failure with preserved ejection fraction in end-stage renal disease patients.

OBJECTIVES: To explore the diagnostic potential of texture analysis applied to native T1 maps obtained from cardiac magnetic resonance (CMR) images for the assessment of heart failure with preserved ejection fraction (HFpEF) among patients with end-stage renal disease (ESRD). METHODS: This study, conducted from June 2018 to November 2020, included 119 patients (35 on hemodialysis, 55 on peritoneal dialysis, and 29 with kidney transplants) in Renji Hospital. Native T1 maps were assessed with texture analysis, using a freely available software package, in participants who underwent cardiac MRI at 3.0 T. Four texture features, selected by dimension reduction specific to the diagnosis of HFpEF, were analyzed. Multivariate logistic regression was performed to examine the independent association between the selected features and HFpEF in ESRD patients. RESULTS: Seventy-six of 119 patients were diagnosed with HFpEF. Demographic, laboratory, cardiac MRI, and echocardiogram characteristics were compared between HFpEF and non-HFpEF groups. The four texture features that were analyzed showed statistically significant differences between groups. In multivariate analysis, age, left atrial volume index (LAVI), and sum average 4 (SA4) turned out to be independent predictors for HFpEF in ESRD patients. Combining the texture feature, SA4, with typical predictive factors resulted in higher C-index (0.923 vs. 0.898, p = 0.045) and a sensitivity and specificity of 79.2% and 95.2%, respectively. CONCLUSIONS: Texture analysis of T1 maps adds diagnostic value to typical clinical parameters for the assessment of heart failure with preserved ejection fraction in patients with end-stage renal disease. KEY POINTS: • Non-invasive assessment of HFpEF can help predict prognosis in ESRD patients and help them take timely preventative measures. • Texture analysis of native T1 maps adds diagnostic value to the typical clinical parameters for the assessment of HFpEF in patients with ESRD.

Assessment of Splenic Switch-Off With Arterial Spin Labeling in Adenosine Perfusion Cardiac MRI.

BACKGROUND: In patients with suspected coronary artery disease (CAD), myocardial perfusion is assessed under rest and pharmacological stress to identify ischemia. Splenic switch-off, defined as the stress to rest splenic perfusion attenuation in response to adenosine, has been proposed as an indicator of stress adequacy. Its occurrence has been previously assessed in first-pass perfusion images, but the use of noncontrast techniques would be highly beneficial. PURPOSE: To explore the ability of pseudo-continuous arterial spin labeling (PCASL) to identify splenic switch-off in patients with suspected CAD. STUDY TYPE: Prospective. POPULATION: Five healthy volunteers (age 24.8 ± 3.8 years) and 32 patients (age 66.4 ± 8.2 years) with suspected CAD. FIELD STRENGTH/SEQUENCE: A 1.5-T/PCASL (spin-echo) and first-pass imaging (gradient-echo). ASSESSMENT: In healthy subjects, multi-delay PCASL data (500-2000 msec) were acquired to quantify splenic blood flow (SBF) and determine the adequate postlabeling delay (PLD) for single-delay acquisitions (PLD > arterial transit time). In patients, single-delay PCASL (1200 msec) and first-pass perfusion images were acquired under rest and adenosine conditions. PCASL data were used to compute SBF maps and SBF stress-to-rest ratios. Three observers classified patients into "switch-off" and "failed switch-off" groups by visually comparing rest-stress perfusion data acquired with PCASL and first-pass, independently. First-pass categories were used as reference to evaluate the accuracy of quantitative classification. STATISTICAL TESTS: Wilcoxon signed-rank, Pearson correlation, kappa, percentage agreement, Generalized Linear Mixed Model, Mann-Whitney, Pearson Chi-squared, receiver operating characteristic, area-under-the-curve (AUC) and confusion matrix. SIGNIFICANCE: P value < 0.05. RESULTS: A total of 27 patients (84.4%) experienced splenic switch-off according to first-pass categories. Comparison of PCASL-derived SBF maps during stress and rest allowed assessment of splenic switch-off, reflected in a reduction of SBF values during stress. SBF stress-to-rest ratios showed a 97% accuracy (sensitivity = 80%, specificity = 100%, AUC = 85.2%). DATA CONCLUSION: This study could demonstrate the feasibility of PCASL to identify splenic switch-off during adenosine perfusion MRI, both by qualitative and quantitative assessments. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: 2.