Extracellular Volume Mapping Research Articles

Oxygen-sensitive Magnetic Resonance Imaging: A Noninvasive Step Forward for Diagnosing Vasculopathy in the Cardiac Allograft.

Oxygen-sensitive Magnetic Resonance Imaging: A Noninvasive Step Forward for Diagnosing Vasculopathy in the Cardiac Allograft.

Recurrent acute pericarditis diagnosed by extra-cellular volume maps.

Recurrent acute pericarditis diagnosed by extra-cellular volume maps.

Myocardial Vascular Function Assessed by Dynamic Oxygenation-sensitive Cardiac Magnetic Resonance Imaging Long-term Following Cardiac Transplantation.

Coronary vascular function is related to adverse outcomes following cardiac transplantation (CTx) in patients with or without cardiac allograft vasculopathy (CAV). The noninvasive assessment of the myocardial vascular response using oxygenation-sensitive cardiac magnetic resonance (OS-CMR has not been investigated in stable long-term CTx recipients). CTx patients were prospectively recruited to complete a CMR study with a breathing maneuver of hyperventilation followed by a voluntary apnea. Changes in OS-sensitive signal intensity reflecting the myocardial oxygenation response were monitored and expressed as % change in response to these breathing maneuvers. Myocardial injury was further investigated with T2-weighted imaging, native and postcontrast T1 measurements, extracellular volume measurements, and late gadolinium enhancement. Forty-six CTx patients with (n = 23) and without (n = 23) CAV, along with 25 healthy controls (HC), were enrolled. The OS response was significantly attenuated in CTx compared with HC at the 30-second time-point into the breath-hold (2.63% ± 4.16% versus 6.40% ± 5.96%; P = 0.010). Compared with HC, OS response was lower in CTx without CAV (2.62% ± 4.60%; P < 0.05), while this response was further attenuated in patients with severe CAV (grades 2-3, -2.24% ± 3.65%). An inverse correlation was observed between OS-CMR, ventricular volumes, and diffuse fibrosis measured by extracellular volume mapping. In heart transplant patients, myocardial oxygenation is impaired even in the absence of CAV suggesting microvascular dysfunction. These abnormalities can be identified by oxygenation-sensitive CMR using simple breathing maneuvers.

Early Comprehensive Cardiovascular Magnetic Resonance Imaging in Patients With Myocardial Infarction With Nonobstructive Coronary Arteries

ObjectivesThe objective of the SMINC-2 (Stockholm Myocardial Infarction With Normal Coronaries 2) study was to determine if more than 70% of patients with myocardial infarction with nonobstructed coronary arteries (MINOCA), investigated early with comprehensive cardiovascular magnetic resonance (CMR), could receive a diagnosis entirely by imaging. BackgroundThe etiology of MINOCA is heterogeneous, including coronary, cardiac, and noncardiac causes. Patients with MINOCA, therefore, represent a diagnostic challenge where CMR is increasingly used. MethodsThe SMINC-2 study was a prospective study of 148 patients with MINOCA imaged with 1.5-T CMR with T1 and extracellular volume mapping early after hospital admission, compared to 150 patients with MINOCA imaged using 1.5-T CMR without mapping techniques from the SMINC-1 study as historic controls. ResultsCMR was performed at a median of 3 (SMINC-2) versus 12 (SMINC-1) days after hospital admission. In total, 77% of patients received a diagnosis with CMR imaging in the SMINC-2 study compared to 47% in the SMINC-1 study (p < 0.001). Compared to SMINC-1, CMR in SMINC-2 detected higher proportions of myocarditis (17% vs. 7%; p = 0.01) and takotsubo syndrome (35% vs. 19%; p = 0.002) but similar proportions of myocardial infarction (22% vs. 19%; p = 0.56) and other cardiomyopathies (3% vs. 2%; p = 0.46). ConclusionsThe results of the SMINC-2 study show that 77% of all patients with MINOCA received a diagnosis when imaged early with CMR, including advanced tissue characterization, which was a considerable improvement in comparison to the SMINC-1 study. This supports the use of early CMR imaging as a diagnostic tool in the investigation of patients with MINOCA. (Stockholm Myocardial Infarction With Normal Coronaries [SMINC]-2 Study on Diagnosis Made by Cardiac MRI [SCMINC-2]; NCT02318498)

Cardiac Magnetic Resonance-Derived Extracellular Volume Mapping for the Quantification of Hepatic and Splenic Amyloid.

Systemic amyloidosis is characterized by amyloid deposition that can involve virtually any organ. Splenic and hepatic amyloidosis occurs in certain types, in some patients but not others, and may influence prognosis and treatment. SAP (serum amyloid P component) scintigraphy is uniquely able to identify and quantify amyloid in the liver and spleen, thus informing clinical management, but it is only available in 2 centers globally. The aims of this study were to examine the potential for extracellular volume (ECV) mapping performed during routine cardiac magnetic resonance to: (1) detect amyloid in the liver and spleen and (2) estimate amyloid load in these sites using SAP scintigraphy as the reference standard. Five hundred thirty-three patients referred to the National Amyloidosis Centre, London, between 2015 and 2017 with suspected systemic amyloidosis who underwent SAP scintigraphy and cardiac magnetic resonance with T1 mapping were studied. The diagnostic performance of ECV to detect splenic and hepatic amyloidosis was high for both organs (liver: area under the curve, -0.917 [95% CI, 0.880-0.954]; liver ECV cutoff, 0.395; sensitivity, 90.7%; specificity, 77.7%; P<0.001; spleen: area under the curve, -0.944 [95% CI, 0.925-0.964]; spleen ECV cutoff, 0.385; sensitivity, 93.6%; specificity, 87.5%; P<0.001). There was good correlation between liver and spleen ECV and amyloid load assessed by SAP scintigraphy (r=0.504, P<0.001; r=0.693, P<0.001, respectively). There was high interobserver agreement for both the liver and spleen (ECV liver intraclass correlation coefficient, 0.991 [95% CI, 0.984-0.995]; P<0.001; ECV spleen intraclass correlation coefficient, 0.995 [95% CI, 0.991-0.997]; P<0.001) with little bias across a wide range of ECV values. Our study demonstrates that ECV measurements obtained during routine cardiac magnetic resonance scans in patients with suspected amyloidosis can identify and measure the magnitude of amyloid infiltration in the liver and spleen, providing important clues to amyloid type and offering a noninvasive measure of visceral amyloid burden that can help guide and track treatment.

Multi-parametric cardiovascular magnetic resonance with regadenoson stress perfusion is safe following pediatric heart transplantation and identifies history of rejection and cardiac allograft vasculopathy

BackgroundThe progressive risk of graft failure in pediatric heart transplantation (PHT) necessitates close surveillance for rejection and coronary allograft vasculopathy (CAV). The current gold standard of surveillance via invasive coronary angiography is costly, imperfect and associated with complications. Our goal was to assess the safety and feasibility of a comprehensive multi-parametric CMR protocol with regadenoson stress perfusion in PHT and evaluate for associations with clinical history of rejection and CAV.MethodsWe performed a retrospective review of 26 PHT recipients who underwent stress CMR with tissue characterization and compared with 18 age-matched healthy controls. CMR protocol included myocardial T2, T1 and extracellular volume (ECV) mapping, late gadolinium enhancement (LGE), qualitative and semi-quantitative stress perfusion (myocardial perfusion reserve index; MPRI) and strain imaging. Clinical, demographics, rejection score and CAV history were recorded and correlated with CMR parameters.ResultsMean age at transplant was 9.3 ± 5.5 years and median duration since transplant was 5.1 years (IQR 7.5 years). One patient had active rejection at the time of CMR, 11/26 (42%) had CAV 1 and 1/26 (4%) had CAV 2. Biventricular volumes were smaller and cardiac output higher in PHT vs. healthy controls. Global T1 (1053 ± 42 ms vs 986 ± 42 ms; p < 0.001) and ECV (26.5 ± 4.0% vs 24.0 ± 2.7%; p = 0.017) were higher in PHT compared to helathy controls. Significant relationships between changes in myocardial tissue structure and function were noted in PHT: increased T2 correlated with reduced LVEF (r = − 0.57, p = 0.005), reduced global circumferential strain (r = − 0.73, p < 0.001) and reduced global longitudinal strain (r = − 0.49, p = 0.03). In addition, significant relationships were noted between higher rejection score and global T1 (r = 0.38, p = 0.05), T2 (r = 0.39, p = 0.058) and ECV (r = 0.68, p < 0.001). The presence of even low-grade CAV was associated with higher global T1, global ECV and maximum segmental T2. No major side effects were noted with stress testing. MPRI was analyzed with good interobserver reliability and was lower in PHT compared to healthy controls (0.69 ± − 0.21 vs 0.94 ± 0.22; p < 0.001).ConclusionIn a PHT population with low incidence of rejection or high-grade CAV, CMR demonstrates important differences in myocardial structure, function and perfusion compared to age-matched healthy controls. Regadenoson stress perfusion CMR could be safely and reliably performed. Increasing T2 values were associated with worsening left ventricular function and increasing T1/ECV values were associated with rejection history and low-grade CAV. These findings warrant larger prospective studies to further define the role of CMR in PHT graft surveillance.

Cardiovascular magnetic resonance imaging reveals asymptomatic cardiomyopathy in newly diagnosed, HIV-infected South African adults

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): University of Stellenbosch Cardiology Research Fund and United States National Institutes of Health/Fogarty International Center Background Cardiovascular disease (CVD) is a leading cause of death and disability in people living with HIV (PLWH). The coronary disease burden in high income countries contrast what is experienced in low- and middle-income countries where cardiomyopathy remains prevalent. Cardiovascular magnetic resonance imaging (CMR) has the unique ability to characterise tissues to obtain "virtual histology". Our data support a high burden of myocardial disease, already present at the time of HIV diagnosis in a young South African cohort. Purpose Early, undiagnosed myocardial pathology in some antiretroviral therapy (ART) naïve persons appear to precede the development of poorly prognostic HIV associated cardiomyopathy. The burden and mechanisms underlying the progression to more advanced disease in treatment naïve PLWH remain largely unknown, as does the modifying effect of ART on these abnormalities. Studying early myocardial disease and its progression with serial CMR evaluation will improve our understanding of disease evolution. Methods 24 newly diagnosed, ART naïve adults without known CVD underwent a contrasted, 1.5T CMR study. Assessments included: Left ventricular (LV) volumes, mass, ejection fraction (EF), native and post-contrast T1 mapping, T2 mapping, extracellular volume (ECV) mapping, and late gadolinium enhancement (LGE) imaging. Quantitative measurements were obtained using a semi-automated software. Qualitative LGE findings were reviewed by an EACVI level III accredited cardiologist. Results The median age of the cohort was 33, interquartile range (IQR) 30-43 years. Median CD4 count was 250, IQR 152-520 cells/uL. All patients had non-dilated LV"s according to indexed end diastolic volumes (Mean: 85 ± 15ml/m²). No patient had overt systolic dysfunction (Mean EF: 62 ± 6%). Non-trivial pericardial effusions were present in 71% of cases. Indexed LV mass measured normal (Mean: 65 ± 12g/m²). Mean global native T1 and T2 values were 1043 ± 46 and 49 ± 4ms respectively. Native T1 values were highest in the septum and inferior wall (Mean: 1054 ± 50 and 1047 ± 51ms respectively). Mean global ECV was 28 ± 4%. Non-ischaemic LGE was present in 71% of participants. In those with LGE, midmyocardial enhancement of the inferior septum represented 71% of abnormalities (Figure). Conclusion In this young cohort of newly diagnosed HIV-infected persons, the prevalence of myocardial abnormalities were high. The midmyocardial LGE and abnormal mapping parameters (high for our scanner and high normal for published data) suggest myocardial inflammation and fibrosis already present at HIV-diagnosis. This was most appreciable in the septum and inferior walls, and likely represents a diffuse process that may progress to symptomatic cardiomyopathy over time. Serial evaluation on ART and comparison with a matched HIV-negative control group is planned. This will allow quantitative comparison of tissue characterisation and explore the nature and evolution of these abnormalities. Abstract Figure. Late gadolinium enhancement (Arrows)

Cardiovascular Magnetic Resonance Mapping and Strain Assessment for the Diagnosis of Cardiac Involvement in Idiopathic Inflammatory Myopathy Patients With Preserved Left Ventricular Ejection Fraction.

The aim of the study was to evaluate the role of cardiac magnetic resonance (CMR) mapping and strain analysis in the identification of cardiac involvement in idiopathic inflammatory myopathy (IIM) patients with preserved left ventricular ejection fraction. In all, 38 IIM patients who underwent CMR examination at our institution were retrospectively included. Twenty-three age-matched healthy individuals served as controls. Mapping parameters including native T1, extracellular volume (ECV), and T2 mapping and strain parameters including global radial strain, global circumferential strain, and global longitudinal strain were measured semiautomatically using a dedicated processing software. All the mapping and strain values were compared between patients and controls. Late gadolinium enhancement was only present in IIM patients (n=17, 44.7%). IIM patients showed higher native T1 (1346 vs. 1269 ms, P<0.001), ECV (31.1% vs. 27.4%, P<0.01), and higher T2 (44.4 vs. 39.2 ms, P<0.001) values compared with controls. The global radial strain (36.7% vs. 46.9%, P<0.001), global circumferential strain (-21.2% vs. -24.1%, P<0.01), and global longitudinal strain (-13.6% vs. -15.6%, P<0.05) values were significantly reduced compared with controls. Native T1, ECV, T2 values, and global strain values may hold promise for the detection of subclinical myocardial involvement in IIM patients with preserved left ventricular ejection fraction.

Cardiac Magnetic Resonance Imaging in Coronavirus Disease 2019 (COVID-19): A Systematic Review of Cardiac Magnetic Resonance Imaging Findings in 199 Patients.

Cardiac magnetic resonance imaging (CMR) with its new quantitative mapping techniques has proved to be an essential diagnostic tool for detecting myocardial injury associated with coronavirus disease 2019 (COVID-19) infection. This systematic review sought to assess the important imaging features on CMR in patients diagnosed with COVID-19. We performed a systematic literature review within the PubMed, Embase, Google Scholar, and WHO databases for articles describing the CMR findings in COVID-19 patients. A total of 34 studies comprising 199 patients were included in the final qualitative synthesis. Of the CMRs 21% were normal. Myocarditis (40.2%) was the most prevalent diagnosis. T1 (109/150; 73%) and T2 (91/144; 63%) mapping abnormalities, edema on T2/STIR (46/90; 51%), and late gadolinium enhancement (LGE) (85/199; 43%) were the most common imaging findings. Perfusion deficits (18/21; 85%) and extracellular volume mapping abnormalities (21/40; 52%), pericardial effusion (43/175; 24%), and pericardial LGE (22/100; 22%) were also seen. LGE was most commonly seen in the subepicardial location (81%) and in the basal-mid part of the left ventricle in inferior segments. In most of the patients, ventricular functions were normal. Kawasaki-like involvement with myocardial edema without necrosis/LGE (4/6; 67%) was seen in children. CMR is useful in assessing the prevalence, mechanism, and extent of myocardial injury in COVID-19 patients. Myocarditis is the most common imaging diagnosis, with the common imaging findings being mapping abnormalities and myocardial edema on T2, followed by LGE. As cardiovascular involvement is associated with poor prognosis, its detection warrants prompt attention and appropriate treatment.

Texture analysis applied in T1 maps and extracellular volume obtained using cardiac MRI in the diagnosis of hypertrophic cardiomyopathy and hypertensive heart disease compared with normal controls

To assess the potential of texture analysis (TA) applied in T1 maps and extracellular volume (ECV) obtained using cardiac magnetic resonance (CMR) in the diagnosis of hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD) compared with normal controls (NC). Strain parameters were analysed to compare with final TA models. This retrospective study included 66 HCM patients, 39 HHD patients, and 41 NC. Step-wise dimension reduction and feature selection were performed by reproducibility, machine learning, collinearity, and multivariable regression analysis to select the texture features that enable diagnosis of and differentiation between HCM and HHD. Strain parameters were calculated by short-axis and three long-axis cine sequences. Independent features in T1 maps and ECV analysis allowed for the differentiation between patients (HCM and HHD) and NC. Of the best-calculated model, the areas under the receiver operating curve (AUCs) were as follows: 0.969 for T1 map and 0.964 for ECV. To distinguish HCM from HHD, two independent features were screened out for both T1 and ECV maps. The AUCs were as follows: 0.793 for T1 map and 0.894 for ECV. Radial, circumferential, and longitudinal strain parameters could differentiate patients from NC, but only longitudinal strain parameters was significantly different between HCM and HHD. Texture analysis of T1 maps and ECV shows high accuracy in differentiating hypertrophic myocardium from NC, and HCM from HHD. Strain parameters are able to demonstrate the difference between patients and NC, but were less impressive in differentiating HCM and HHD.

Abstract 15703: Cardiac Magnetic Resonance Imaging Can Non-invasively Detect Rejection in Pediatric Heart Transplant Recipients

Introduction: Pediatric heart transplant recipients (PHTx) undergo frequent surveillance endomyocardial biopsies (EMB). Non-invasive screening for acute rejection (AR) could decrease morbidity, improve quality of life, and decrease healthcare costs. Hypothesis: We hypothesized that cardiac magnetic resonance (CMR) extracellular volume (ECV), native T1, and T2 mapping can detect AR in PHTx. Methods: PHTx (n=29) were prospectively enrolled at two sites at time of surveillance EMB or EMB for AR. AR was defined as a clinical change or positive EMB requiring intensification of immunosuppression. Subjects with cardiac allograft vasculopathy (n=3) were excluded; ECV was not measured in 2 subjects without rejection (no IV, poor breathholds). CMR without sedation included standard volumetrics, modified Look-Locker inversion recovery before and after contrast, and T2 mapping. A Wilcoxon rank sum was used to assess for a difference between groups. Results: Median age was 17 y/o (range 9-19). There were 9 subjects with and 17 subjects without AR. Base ECV, mid ECV, 4-ch ECV, and average ECV were increased in AR vs non-rejection (Table 1, Fig 1). Native T1 and T2 times were also increased in patients with AR (Table 1). A cut-off of 29% for mid ECV and 1070ms for mid native T1 identifies all patients with rejection with 6 false positive results in non-rejection (Fig 1) and could potentially decrease the need for EMB by 65%. Conclusions: ECV, native T1, and T2 mapping can non-invasively distinguish between PHTx with and without AR and have potential to decrease the required number of surveillance EMBs.

Abstract 17385: Soluble CD163 Predicts Myocardial Fibrosis in People Living With Human Immunodeficiency Virus Infection: Myocardial and Coronary Abnormalities in HIV Infection (MACHIN) Study

Background: Soluble CD163 (sCD163) is a scavenger receptor that is shed during inflammation and monocyte/macrophage activation and appears to be useful in resolution of the inflammation. This marker has been associated with increased mortality and morbidity in several inflammatory conditions. Hypothesis: sCD163 levels are related to myocardial fibrosis (MF) in people living with HIV infection (PLWH) and controls. Methods: sCD163 levels were measured in serum samples of 92 participants (54 PLWH and 38 HIV- controls, mean age 47±14 years, 28% female).. Myocardial structure and function were assessed using CMR (GE 3.0T; acquisition: RT-Hawk, Heart Vista Inc; analysis: cvi42, Circle Inc, v5.10). Our protocol included cine, pre-contrast, 12-minute post contrast T1 mapping and LGE after infusion of 0.1mmol/kg of gadolinium (Multihance). 12-minute ECV (extra cellular volume) maps were generated from T1 maps. Results: We studied 40 PLWH and 28 HIV- controls (mean age 45±14 years, 46% men). HIV-positive individuals had significantly higher levels of sCD163, compared to controls ( mean±SD: 78±6 versus 54±5 ng/dL, p-value&lt;0.01). The association of sCD163 with diffuse fibrosis detected by ECV was modified by HIV infection (p-value for interaction term: 0.05). log-sCD163 levels were significantly associated with ECV in PLWH (regression coefficient: 9, 95% CI:2-15, p:0.01), but not in controls (p:0.74). The significant association of sCD163 with ECV remained significant even after adjusting for age, gender, race, and LVEF (p:0.02) and even after adding history of protease inhibitor and abacavir use to the models (p:0.02). But after adding both nadir CD4 and highest viral load to the above model, the association was not significant (p:0.08). LGE was not significantly associated with sCD163 levels. Conclusions: Soluble CD163, as a marker of monocyte/macrophage activation, is associated with increased diffuse subclinical MF, estimated by postcontrast ECV, in virologically-suppressed PLWH. Importantly, this association is independent of demographic factors, LV function, and ART medication use. These findings highlight the importance of chronic sustained inflammation in development of MF in PLWH.

Abstract 15710: Myocardial Ischaemia in Cardiac Amyloidosis, Changing Perspectives

Introduction: Cardiac involvement determines outcome in systemic amyloidosis, but the relationship between amyloid deposits and outcomes is poorly understood. Many clinical observations are not explained by the simple concept of physical, mechanical replacement of the interstitium by amyloid material. Hypothesis: Preliminary studies in patients with cardiac amyloidosis (CA) support the hypothesis that myocardial ischaemia contributes to cell damage. This study assesses the presence and mechanisms of myocardial ischaemia using CMR with multiparametric mapping and histopathological assessment. Methods: 92 patients with CA (41 AL, 51 ATTR) and 73 without CA (26 with unobstructed coronary arteries; 47 with 3VD) underwent CMR with T1, T2, Extracellular volume (ECV) mapping and adenosine stress with myocardial blood flow (MBF) mapping. 25 cardiac biopsies and 3 explanted hearts with CA were analysed histopathologically. Results: CA patients had severe reductions in stress MBF and myocardial perfusion reserve (MPR)- (1.03ml/g/min±0.50;1.54±0.59 ) compared to patients with unobstructed coronary arteries (2.82 ml/g/min±0.53; 2.94±0.59, p&lt;0.001), and comparable only to 3VD (1.32±0.47ml/g/min, p=0.04;1.49±0.44, p=1.00). Myocardial perfusion abnormalities correlated with amyloid burden, systolic function and blood biomarkers (p&lt;0.001). Biopsies showed evidence of diffuse hypoxia with abnormal VEGF staining in cardiomyocytes and endothelial cells. Amyloid infiltration in intramural arteries was associated with severe lumen reduction in 20% of vessels, with severe reduction in capillary density in areas with and without amyloid deposits. Conclusion: CA is associated with severe myocardial ischaemia demonstrable by histology and CMR perfusion mapping. Histological evaluation indicates a complex pathophysiology, where direct disruption of the vessels by amyloid deposits and reduction in epicardial flow contribute to myocardial ischaemia.

Abstract 17131: Myocardial Fibrosis Measured by Magnetic Resonance Imaging in People Living With Human Immunodeficiency Virus and Ethnic Differences: Myocardial and Coronary Abnormalities in HIV Infection (MACHIN) Study

Introduction: Recent studies have suggested that increased risk of cardiovascular disease (CVD) in people living with HIV (PLWH) extends beyond coronary artery disease to involve myocardial fibrosis. Cardiac MRI can accurately detect overt scar and diffuse fibrosis in this population. Hypothesis: Compared to controls, virologically-suppressed PLWH without known clinical CVD have increased risk of myocardial fibrosis and scar, as demonstrated by T1/ECV (extracellular volume) mapping and late gadolinium enhancement (LGE) respectively. Methods: Myocardial structure and function were assessed using CMR (GE 3.0T; acquisition: RT-Hawk, Heart Vista Inc; analysis: cvi42, Circle Inc, v5.10). Our protocol included cine, pre-contrast images, LGE and post contrast T1 mapping 12 minutes after infusion of 0.1mmol/kg of gadolinium (Multihance). 12-minute ECV maps were generated and ECV&gt;32% was considered increased extracellular volume indicating diffuse fibrosis. Results: We studied 92 participants (54 PLWH and 38 HIV- controls, mean age 47±14 years, 28% female). There was no difference in LV systolic function and mass between groups. Clinically detectable LGE was observed in 5 PLWH (10%) and no controls (p :0.04). While there was no significant difference in pre-contrast T1 values in cases vs controls (1044±14 vs 1023±15 ms, p: 0.30), PLWH were more likely to have 12mECV values above the median of 25.5% (57% vs 41%, p: 0.23). In regression models, PLWH had higher ECV values (coefficient: 3.4%, p:0.04) and higher odds of increased ECV (OR: 3.9, 95%CI: 1.0-15.6, p:0.05) adjusted for age, gender, and ethnicity. In multivariable models, women had significantly lower ECV values (p: 0.04). African Americans (AAs) had significantly higher chance of having LGE (OR:12.6, p: 0.03). However, while non-black PLWH had a significantly higher odds of increased ECV (adjusted OR:6.0, p: 0.03), this association was not significant in AAs (p:0.9). Conclusion: Virologically suppressed PLWH are at higher risk of clinically detectable LGE in myocardium and diffuse myocardial fibrosis, independent of their demographics and cardiac function. HIV infection is associated with higher risk of LGE in AAs, while subclinical increased ECV is the more common finding in other ethnicities.

Abstract 16060: Cardiac Magnetic Resonance Imaging Diastolic Indices Correlate With Cardiac Catheterization Filling Pressures in Pediatric Heart Transplant Recipients

Background: Atrial and ventricular filling pressures are routinely used in pediatric heart transplant (HTx) recipients to assess graft function. Cardiac magnetic resonance (CMR) can provide a non-invasive assessment of diastolic function, but data are lacking in pediatric HTx. We hypothesized that CMR indices of diastolic function correlate with filling pressures, providing a non-invasive approach to assessment of ventricular dysfunction. Method: Pediatric HTx recipients were prospectively enrolled at the time of cardiac catheterization. Pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP) were measured. CMR included standard volumetric analysis and T1 and extracellular volume (ECV) mapping in the short axis at the mid-left ventricle (LV) to evaluate extracellular matrix expansion. Filling curves were calculated by contouring every phase in the short axis stack and global longitudinal and circumferential strain (GLS, GCS) were calculated using feature tracking. Correlations were analyzed using Spearman’s correlation. Results: A total of 31 patients with a mean age of 16.2 y/o were included, 9 with biopsy-proven acute rejection. The median time from transplant was 6.9 years and the mean LVEF was 58%. Peak LV ejection rate/end-diastolic volume (PER/EDV) correlated with PCWP (rho=-0.43, p=0.02, Fig 1) and RAP (rho=-0.40, p=0.03). GLS and GCS correlated with RAP (rho=0.51 p=0.007, and rho=0.38 p=0.05, respectively); GLS also correlated with PCWP (rho=0.46, p=0.02). Native T1 time-correlated with PCWP (rho=0.54, p=0.003), while the correlation between ECV and PCWP did not reach statistical significance (rho=0.37, p=0.06). Conclusion: CMR can be a useful non-invasive modality to assess for early signs of diastolic dysfunction in patients after pediatric HTx. Further research is needed to describe the clinical significance of these associations.

T1, T2, and Fat Fraction Cardiac MR Fingerprinting: Preliminary Clinical Evaluation.

Dixon cardiac magnetic resonance fingerprinting (MRF) has been recently introduced to simultaneously provide water T1 , water T2 , and fat fraction (FF) maps. To assess Dixon cardiac MRF repeatability in healthy subjects and its clinical feasibility in a cohort of patients with cardiovascular disease. T1MES phantom, water-fat phantom, 11 healthy subjects and 19 patients with suspected cardiovascular disease. Prospective. 1.5T, inversion recovery spin echo (IRSE), multiecho spin echo (MESE), modified Look-Locker inversion recovery (MOLLI), T2 gradient spin echo (T2 -GRASE), 6-echo gradient rewound echo (GRE), and Dixon cardiac MRF. Dixon cardiac MRF precision was assessed through repeated scans against conventional MOLLI, T2 -GRASE, and PDFF in phantom and 11 healthy subjects. Dixon cardiac MRF native T1 , T2 , FF, postcontrast T1 and synthetic extracellular volume (ECV) maps were assessed in 19 patients in comparison to conventional sequences. Measurements in patients were performed in the septum and in late gadolinium enhanced (LGE) areas and assessed using mean value distributions, correlation, and Bland-Altman plots. Image quality and diagnostic confidence were assessed by three experts using 5-point scoring scales. Paired Wilcoxon rank signed test and paired t-tests were applied. Statistical significance was indicated by *(P < 0.05). Dixon cardiac MRF showed good overall precision in phantom and in vivo. Septal average repeatability was ~23 msec for T1 , ~2.2 msec for T2 , and ~1% for FF. Biases in healthy subjects/patients were measured at +37 msec*/+60 msec* and -8.8 msec*/-8 msec* when compared to MOLLI and T2 -GRASE, respectively. No statistically significant differences in postcontrast T1 (P = 0.17) and synthetic ECV (P = 0.19) measurements were observed in patients. Dixon cardiac MRF attained good overall precision in phantom and healthy subjects, while providing coregistered T1 , T2 , and fat fraction maps in a single breath-hold scan with similar or better image quality than conventional methods in patients. 2. 2.

Reduction in CMR Derived Extracellular Volume With Patisiran Indicates Cardiac Amyloid Regression

ObjectivesThe purpose of this study was to determine the effect of patisiran on the cardiac amyloid load as measured by cardiac magnetic resonance and extracellular volume (ECV) mapping in cases of transthyretin cardiomyopathy (ATTR-CM). BackgroundAdministration of patisiran, a TTR-specific small interfering RNA (siRNA), has been shown to benefit neuropathy in patients with hereditary ATTR amyloidosis, but its effect on ATTR-CM remains uncertain. MethodsPatisiran was administered to 16 patients with hereditary ATTR-CM who underwent assessment protocols at the UK National Amyloidosis Centre. Twelve of those patients concomitantly received diflunisal as a “TTR-stabilizing” drug. Patients underwent serial monitoring using cardiac magnetic resonance, echocardiography, cardiac biomarkers, bone scintigraphy, and 6-min walk tests (6MWTs). Findings of amyloid types and extracellular volumes were compared with those of 16 patients who were retrospectively matched based on cardiac magnetic resonance results. ResultsPatisiran was well tolerated. Median serum TTR knockdown among treated patients was 86% (interquartile range [IQR]: 82% to 90%). A total of 82% of cases showed >80% knockdown. Patisiran therapy was typically associated with a reduction in ECV (adjusted mean difference between groups: −6.2% [95% confidence interval [CI]: −9.5% to −3.0%]; p = 0.001) accompanied by a fall in N-terminal pro–B-type natriuretic peptide concentrations (adjusted mean difference between groups: −1,342 ng/l [95% CI: −2,364 to −322]; p = 0.012); an increase in 6MWT distances (adjusted mean differences between groups: 169 m [95% CI: 57 to 2,80]; p = 0.004) after 12 months of therapy; and a median reduction in cardiac uptake by bone scintigraphy of 19.6% (IQR: 9.8% to 27.1%). ConclusionsReductions in ECV by cardiac magnetic resonance provided evidence for ATTR cardiac amyloid regression in a proportion of patients receiving patisiran.

The role of cardiac magnetic resonance imaging in the detection and monitoring of cardiotoxicity in patients with breast cancer after treatment: a comprehensive review.

The use of chemotherapy medicines for breast cancer (BC) has been associated with an increased risk of cardiotoxicity. In recent years, there have been growing interests regarding the application of cardiovascular magnetic resonance (CMR) imaging, a safe and noninvasive modality, with the potential to identify subtle morphological and functional changes in the myocardium. In this investigation, we aimed to review the performance of various CMR methods in diagnosing cardiotoxicity in BC, induced by chemotherapy or radiotherapy. For this purpose, we reviewed the literature available in PubMed, MEDLINE, Cochrane, Google Scholar, and Scopus databases. Our literature review showed that CMR is a valuable modality for identifying and predicting subclinical cardiotoxicity induced by chemotherapy. The novel T1, T2, and extracellular volume mapping techniques may provide critical information about cardiotoxicity, in addition to other CMR features such as functional and structural changes. However, further research is needed to verify the exact role of these methods in identifying cardiotoxicity and patient management. Since multiple studies have reported the improvement of left ventricular performance following the termination of chemotherapy regimens, CMR remains an essential imaging tool for the prediction of cardiotoxicity and, consequently, decreases the mortality rate of BC due to heart failure.

Myocardial extracellular volume fraction radiomics analysis for differentiation of reversible versus irreversible myocardial damage and prediction of left ventricular adverse remodeling after ST-elevation myocardial infarction.

Our study sought to explore the prognostic value of radiomic TA (texture analysis) on quantitative ECV (extracellular volume) fraction mapping to differentiate between reversible and irreversible myocardial damage and to predict left ventricular adverse remodeling in patients with reperfused STEMI (ST-elevation myocardial infarction). This observational prospective cohort study identified 70 patients (62 ± 9years, 62 men [85.70%]) with STEMI for TA who consecutively performed native and contrast T1 mapping. Texture features were extracted from each stack of ECV mapping based on ROI (region of interest) analysis. After texture feature selection and dimension reduction, five selected texture features were found to be statistically significant for differentiating the extent of myocardial injury. ROC (receiver operating characteristic) curve analysis for the differentiation of unsalvageable infarction and salvageable myocardium demonstrated a significantly higher AUC (area under the curve) (0.91 [95% CI, 0.86-0.96], p < 0.0001) for horizontal fraction than other texture features (p < 0.05). LVAR (left ventricular adverse remodeling) was predicted by those selected features. The differences in qualitative and quantitative baseline parameters and horizontal fractions were significant between the patients with and without LVAR. LGE (late gadolinium enhancement) and horizontal fraction features of infarcted myocardium in acute STEMI were the only two parameters selected in forming the optimal overall multivariable model for LVAR at 6months. Radiomic analysis of ECV could discriminate reversible from irreversible myocardial injury after STEMI. LGE as well as radiomics TA (texture analysis) of ECV may provide an alternative to predict LVAR and functional recovery. • ECV quantification was able to differentiate between infarcted myocardium and non-infarcted myocardium. • Radiomics analysis of ECV could discriminate reversible from irreversible myocardial injury. • Radiomics TA analysis shows a promising similarity with LGE findings which could aid the prognosis of myocardial infarction patients.

Females have higher myocardial perfusion, blood volume and extracellular volume compared to males \u2013 an adenosine stress cardiovascular magnetic resonance study

Knowledge on sex differences in myocardial perfusion, blood volume (MBV), and extracellular volume (ECV) in healthy individuals is scarce and conflicting. Therefore, this was investigated quantitatively by cardiovascular magnetic resonance (CMR). Healthy volunteers (n = 41, 51% female) underwent CMR at 1.5 T. Quantitative MBV [%] and perfusion [ml/min/g] maps were acquired during adenosine stress and at rest following an intravenous contrast bolus (0.05 mmol/kg, gadobutrol). Native T1 maps were acquired before and during adenosine stress, and after contrast (0.2 mmol/kg) at rest and during adenosine stress, rendering rest and stress ECV maps. Compared to males, females had higher perfusion, ECV, and MBV at stress, and perfusion and ECV at rest (p < 0.01 for all). Multivariate linear regression revealed that sex and MBV were associated with perfusion (sex beta −0.31, p = 0.03; MBV beta −0.37, p = 0.01, model R2 = 0.29, p < 0.01) while sex and hematocrit were associated with ECV (sex beta −0.33, p = 0.03; hematocrit beta −0.48, p < 0.01, model R2 = 0.54, p < 0.001). Myocardial perfusion, MBV, and ECV are higher in female healthy volunteers compared to males. Sex is an independent contributor to perfusion and ECV, beyond other physiological factors that differ between the sexes. These findings provide mechanistic insight into sex differences in myocardial physiology.