Contrast-enhanced Cardiac Magnetic Resonance Imaging Research Articles

Stronger positive correlation of the left ventricular mass index and extracellular volume fraction with diastolic function in diabetic patients without myocardial infarction

BackgroundThe structural and functional characteristics of the heart in patients with diabetes mellitus (DM) and without myocardial infarction (MI) are not fully understood. MethodsWe retrospectively analysed the data of patients with left ventricular ejection fraction (LVEF) ≥ 40% who underwent contrast-enhanced cardiac magnetic resonance imaging (CMR), which was also used to exclude MI, at two hospitals. Volumetric data and extracellular volume fraction (ECVf) of the myocardium evaluated using CMR were compared between patients with and without DM, and their association with diastolic function was evaluated. ResultsAmong 322 analysed patients, 53 had DM. CMR revealed that the left ventricular mass index (LVMi) and ECVf were increased while LVEF was decreased in patients with DM after adjusting for patient characteristics (all P < 0.05). A stronger positive correlation was observed between LVMi and the early diastolic transmitral flow velocity to early diastolic mitral annular velocity ratio (E/e′) in patients with DM than in those without DM (correlation coefficient [R] = 0.46, p = 0.001; R = 0.15, p = 0.021, respectively; p for interaction = 0.011). ECVf correlated with E/e′ only in patients with DM (R = 0.61, p = 0.004). ConclusionsPatients with DM have increased LVMi and ECVf. Importantly, there was a difference between patients with and without DM in the relationship between these structural changes and E/e′, with a stronger relationship in patients with DM. Furthermore, DM is associated with mildly reduced LVEF even in the absence of MI.

The value of microvascular obstruction according to contrast-enhanced cardiac magnetic resonance imaging in assessing the prognosis of patients with acute ST-segment elevation myocardial infarction

The value of microvascular obstruction according to contrast-enhanced cardiac magnetic resonance imaging in assessing the prognosis of patients with acute ST-segment elevation myocardial infarction

Role of cardiac magnetic resonance imaging in assessing the risk of various myocardial remodeling types in left ventricular noncompaction: genetic analysis data

Aim. To analyze contrast-enhanced cardiac magnetic resonance imaging (MRI) in patients with phenotypic manifestations of left ventricular non-compaction (LVNC) and related genetic mutations, as well as to determine the relationship between mutations and types of left ventricular (LV) remodeling and with a number of other morphological and functional cardiac parameters.Material and methods. From the registry of patients with LVNC and their relatives, patients with morphological signs of LVNC and 4 related mutations (MYH7, MYBPC3, TTN, and desmin genes (DES, DSG2, DSP and DSC2)). All patients underwent contrast-enhanced cardiac MRI, based on which the type of LV remodeling was determined.Results. The study included 44 patients who, according to genetic analysis, had mutations in sarcomeric genes responsible for LVNC development. In each patient, the type of LV remodeling was determined based on cardiac MRI results. We found that if patients with LVNC have mutations in the MYBPC3 and TTN genes, the chance of LV dilatation remodeling is significantly higher. On the contrary, in the presence of a DES gene mutation, the probability of this LV remodeling is lower, and milder morphological manifestations of LVNC are noted.Conclusion. The combination of cardiac MRI data and genetic analysis improves the morphological and functional stratification of patients with LVNC.

Cardiac Magnetic Resonance Imaging Based Ischemic Injury Pattern in Patients with Acute Myocardial Infarction Sensu Left Ventricular Global Systolic Function.

The purpose of the study was to identify factors characterizing a decrease in LV global systolic function in patients with ST-segment elevation myocardial infarction (STEMI) after revascularization using cardiac magnetic resonance imaging (MRI)-based ischemic injury pattern and laboratory parameters sensu left ventricular global systolic function. A total of 109 STEMI patients were examined. The patients underwent contrast-enhanced cardiac MRI with a 1.5 Tesla GE SIGNA Voyager (GE HealthCare, Chicago, IL, USA) on the 7th-10th days from the onset of the disease. According to cardiac MRI analysis, the patients were divided into the following groups with regard to left ventricular ejection fraction (LVEF) values: Group 1-patients with LVEF ≥ 50%; group 2-patients with mildly reduced LVEF 40-49%; group 3-patients with low LVEF < 40%. A predominance of most parameters of the ischemic injury pattern was noted in patients with mildly reduced and low LVEF versus patient group with LVEF ≥ 50%. Some risk factors for a decrease in LVEF < 50% systolic function in STEMI patients after revascularization were revealed: male gender; time from the onset of the anginal attack to revascularization; coronary artery status; several LV parameters; ischemic injury characteristics; natriuretic peptide and troponin I levels.

Prediction of myocardial contractility after coronary bypass surgery according to preoperative contrast-enhanced magnetic resonance imaging and echocardiography

To establish the criteria for reversibility of myocardial contractility in patients with coronary artery disease (CAD) after coronary artery bypass grafting considering data of cardiac magnetic resonance imaging (MRI) and echocardiography. We studied the results of coronary artery bypass grafting in 186 patients with CAD complicated by reduced left ventricular ejection fraction (<30%). All patients underwent cardiac MRI and echocardiography before surgery. Immediate and long-term results were evaluated according to echocardiography and MRI data. We confirmed the previously established predictors of improvement in left ventricular contractility: diastolic IVST ≥10.5 mm and PWT ≥9.5 mm, score of LV myocardium damage according to MRI with delayed contrast enhancement (p<0.05). Multivariate analysis makes it possible to calculate prognostic index and obtain information about further myocardial contractility after revascularization with an error of 6%. Echocardiography and contrast-enhanced cardiac MRI are valuable to assess morphological and functional state of the left ventricle in patients with ischemic cardiomyopathy and preoperatively determine functional reserve of the myocardium.

Kiosk 1R-TA-08 - Evaluation of Cardiac Function and Infarct Size by Contrast-enhanced Cardiac Magnetic Resonance Imaging in Mice with Myocardial Ischemia Reperfusion Injury: Comparison of Imaging and Staining Data

Kiosk 1R-TA-08 - Evaluation of Cardiac Function and Infarct Size by Contrast-enhanced Cardiac Magnetic Resonance Imaging in Mice with Myocardial Ischemia Reperfusion Injury: Comparison of Imaging and Staining Data

Combined Heart Injuries on the Data of Contrast-Enhanced Cardiac Magnetic Resonance Imaging in Patients With Post-Covid Syndrome.

Aim Prospective assessment of the nature of cardiac injury in patients with post-COVID syndrome according to contrast-enhanced MRI in routine clinical practice.Material and methods 106 previously unvaccinated patients were evaluated. 62 (58.5%) of them were women with complaints that persisted after COVID-19 (median age, 57.5 [49; 64] years). In addition to standard indexes, markers of inflammation and myocardial injury were determined, and cardiac contrast-enhanced MRI was performed in each patient.Results The median time from the onset of COVID-19 to cardiac MRI was 112.5 [75; 151] days. The nature of cardiac injury according to MRI in patients with post-COVID syndrome was complex and included a decrease in left ventricular (LV) and right ventricular ejection fraction, pericardial effusion, and pathological foci of late and early contrast enhancement at various locations. In 29 (27.4%) cases, there was a combination of any two signs of heart injury. In 28 (26.4%) patients with focal myocardial injury during the acute phase of COVID-19, hydroxychloroquine and tocilizumab were administered significantly more frequently, but antiviral drugs were administered less frequently. The presence of focal myocardial injury was associated with pathological LV remodeling.Conclusion According to contrast-enhanced cardiac MRI, at least 27.4% of patients with post-COVID syndrome may have signs of cardiac injury in various combinations, and in 26.4% of cases, foci of myocardial injury accompanied by LV remodeling are detected. The nature of heart injury after COVID-19 depends on the premorbid background, characteristics of the course of the infectious process, and the type of prescribed therapy. An algorithm for evaluating patients with post-COVID syndrome is proposed.

Abstract 12256: The High FIB-4 Index is Independently Associated With an Increased Myocardial Extracellular Volume Fraction Quantified by Contrast-Enhanced Cardiac Magnetic Resonance Imaging

Introduction: Liver fibrosis is associated with heart failure and left ventricular diastolic dysfunction. The fibrosis 4 (FIB-4) index is calculated from transaminases, age, and platelet count and can be used to screen patients with liver fibrosis. The myocardial extracellular volume fraction (ECVf) can be evaluated using contrast-enhanced cardiac magnetic resonance imaging (CMR). Hypothesis: ECVf is increased in patients with high FIB-4 index. AIMS: This study aimed to clarify the association between FIB-4 index and ECVf. Methods: A retrospective analysis was performed on patients aged ≥ 45 years with left ventricular ejection fraction (LVEF) &gt; 40 % who underwent CMR at two Japanese institutions. Patients were divided into 3 groups according to the FIB-4 index: Low: FIB-4 index &lt; 1.3; Intermediate: 1.3 ≤ FIB-4 index &lt; 2.67; High: 2.67 ≤ FIB-4 index. The association between the FIB-4 index and ECVf was evaluated using multiple regression analysis, with the FIB-4 index treated as a continuous and nominal variable. Results: A total of 244 patients were included in the analysis, 136 of whom underwent contrast-enhanced CMR and could be evaluated for ECVf. The ECVf of the high FIB-4 index group was significantly higher than that of the other two groups (High: 31.0 ± 4.3 %; Intermediate: 27.9 ± 3.4 %; Low: 27.6 ± 3.7 %. High vs. Intermediate, p = 0.014; High vs. Low, p = 0.008; Intermediate vs. Low, p = 0.65). Multivariate analysis showed that both the FIB-4 index (continuous variable) and high FIB-4 index (nominal variable) were associated with higher ECVf (continuous variable, p = 0.043; nominal variable, p = 0.016). Conclusions: The high FIB-4 index was independently associated with increased ECVf. In contrast, patients with the intermediate FIB-4 index did not have increased ECVf. These suggested the usefulness of FIB-4 index as a cardiac fibrotic parameter.

Cardiac magnetic resonance imaging in patients with history of COVID-19

BACKGROUND: Myocarditis is among the most common complications arising from coronavirus infection (COVID-19).&#x0D; AIM: This study aims to find the differences in the patterns of myocardial injury between patients who had COVID-19 and those from the pre-pandemic period, as determined by contrast-enhanced cardiac magnetic resonance imaging.&#x0D; MATERIALS AND METHODS: The study encompassed a retrospective analysis of 47 patients who underwent contrast-enhanced cardiac magnetic resonance imaging to rule out acute myocarditis. Group 1 comprised 34 patients with a confirmed history of COVID-19 through PCR testing (nasal and/or throat swabs), while Group 2 comprised 13 individuals who underwent contrast-enhanced cardiac magnetic resonance imaging in 2017 prior to the onset of the COVID-19 pandemic. All patients enrolled in the study had clinical manifestation of cardiac injury without signs of coronary artery disease as an underlying cause of condition.&#x0D; RESULTS: The mean time from the onset of heart symptoms to the administration of contrast-enhanced cardiac magnetic resonance imaging was 166 days. In group 1, a decrease in exercise tolerance was observed in 77% of patients, and 14 (42%), 30 (88%), and 28 (85%) of patients complained of chest pain, shortness of breath, and heart palpitations, respectively. In group 2, four patients (30%) had dyspnea, nine patients (69%) complained of chest pain, and six patients (46%) had heart palpitations and/or feeling of arrhythmia. Myocardial injury in group 1 was more generalized. The third of them had displayed preserved increased pulmonary vascularity and pleural effusion. Within group 1, men had significantly lower left ventricular ejection fraction, lower values of global longitudinal deformation, and higher values of left atrial function compared with the corresponding parameters in women. Differences in women were found only in the number of the affected segments in the left ventricular myocardium.&#x0D; CONCLUSION: SARS-CoV-2 virus caused extended myocardial injury, affecting a significant number of myocardial segments. Men had more frequent postinflammatory complications, characterized by abnormal function of the left ventricle and left atrium. Obtained results require continuous efforts for further assessment of long-term consequences of previous COVID-19 to the cardiovascular system. In this regard, contrast-enhanced cardiac magnetic resonance imaging may represent a sensitive imaging tool for the assessment of cardiac injury severity.

Diagnostic criteria for proximal left bundle branch block and their significance in predicting the success of cardiac resynchronization therapy

Aim. To develop diagnostic criteria for proximal left bundle branch block (LBBB) based on non-invasive methods and to determine the significance of these criteria in predicting the effect of cardiac resynchronization therapy (CRT).Material and methods. To develop criteria, 58 patients (21 men, mean age, 76,1±7,1 years) with LBBB occurred immediately after transcatheter aortic valve implantation (TAVI) were included. To assess the significance of the developed criteria, the second group included 22 patients (11 men, mean age, 57,9±9,3 years) with dilated cardiomyopathy (DCM), who had indications for CRT. The effectiveness of CRT was assessed by echocardiography 6 months after implantation. All patients in the DCM group and 15 patients in the TAVI group underwent superficial epiand endocardial non-invasive mapping using Amycard 01C EP Lab (EP Solutions SA, Switzerland). Patients in the DCM group underwent contrast-enhanced cardiac magnetic resonance imaging (MRI) before device implantation.Results. The criteria for proximal LBBB included 3 electrocardiographic features: QRS complex &gt;130 ms in women and 140 ms in men, QSor rS-configuration in V1 lead, notch in two or more lateral leads (I, avL, V5, V6), and 2 mapping criteria: characteristic location of block line and delayed activation point. In the DCM group, the criteria were positive in 13 of 22 patients (59%). The developed criteria for proximal LBBB showed a relatively strong, significant relationship with the positive effect of CRT (сhi-square test =5,46, p=0,02, Cramer test =0,5, odds ratio (OR)=15,0, 95% confidence interval (CI), 1,32-169,9, p=0,002). An additional analysis showed that both the criteria for proximal block and CRT effect are associated with myocardial fibrosis according to MRI. In particular, intramural stria-shaped contrast accumulation in the interventricular septum leads to a change in characteristic of proximal block mapping phenomena — displacement of delayed activation point (chi-square test =13,9, p&lt;0,001, Cramer test =0,79) and displacement or absence of conduction block lines (chi-square test =6,92, p=0,009, Cramer test =0,56) and prevents the CRT effect (OR =8,67, 95% CI, 1,05-71,57 p=0,03).Conclusion. Proximal LBBB is only one of the factors determining the effectiveness of CRT. Proximal LBBB may mask significant myocardial structural changes that prevent the CRT success.

Effect of ischemic injury characteristics on left ventricular systolic function in patients with acute myocardial infarction

Aim. To study laboratory and magnetic resonance imaging (MRI) characteristics of infarction area depending on left ventricular (LV) global systolic function in patients with acute myocardial infarction (AMI) after revascularization.Material and methods. A total of 78 patients with primary AMI were included. On days 7-10, contrast-enhanced cardiac MRI was performed. Blood brain natriuretic peptide (BNP) was analyzed. Cardiac MRI was used to determine the characteristics of scar tissue, peri-infarct zone (PIZ), microvascular obstruction (MVO), intramyocardial hemorrhage (IMH) and the global contrast index.Results. According to the MRI, patients were divided into following groups: group 1 — LV ejection fraction (LVEF) ≥50% (n=50), group 2 — LVEF 40-49% (n=21), group 3 — LVEF &lt;40% (n=7).The BNP in groups 1, 2, 3 was 106,8 (37,5; 248), 232,6 (170,1; 337,7) and 548,5±236,4 ng/ml, respectively (p1-3&lt;0,05). The scar tissue mass in groups 1, 2, 3 was 10,3 (2,4; 20,0), 34,7±21,3, 59,4±37,6 g, respectively (p1-2, 3&lt;0,01). PIZ differences were found only between patients with preserved and mildly reduced EF. MVO was diagnosed in 26% of patients with LVEF ≥50%, in 47,6% of patients with LVEF of 40-49% and 85,7% with LVEF &lt;40% (p1-3&lt;0,01). The detection rate of IMH prevailed in the 2nd group (33,3%) compared with the 1st group (12%) (p1-2&lt;0,05). The global contrast index was the lowest in the 1st group (14,7 (8,8; 27,9)%), intermediate in the 2nd group (33,3±12,6%), the highest in the 3th group (54,2±19,5%) (р1-2, 3; 2-3&lt;0,05).Conclusion. The following risk factors for a decrease in LV systolic function in patients with AMI after revascularization were identified: the size of scar tissue, PIZ, MVO and IMH characteristics, global contrast index, BNP level.

Association between contrast-enhanced adenosine-stress perfusion cardiac magnetic resonance imaging and invasive coronary angiogram for the detection of coronary artery disease: A retrospective analysis.

The objective of this study was to determine the diagnostic value of stress perfusion CMR for the detection of coronary artery disease. The was a retrospective cross sectional study in which 43 subjects were included from Cardiac MRI unit in the Hayatabad Medical Complex, Peshawar for study from 1st April 2020 to 30th November 2020. All the subjects who had been referred for stress perfusion CMR with suspected CAD were included in the study. Cardiac MRI both at rest and with adenosine stress perfusion was performed which was followed by invasive coronary angiography. A total of 43 patients were enrolled for the detection or exclusion CAD who underwent stress perfusion CMRI and invasive coronary artery angiography. The study revealed strong and statistically significant association between positive stress perfusion CMR and positive coronary angiogram vs negative stress perfusion CMR and negative coronary angiogram (p= value 0.0001). Stress perfusion CMRI can be considered as a first line, relatively safe, noninvasive test with significant accuracy to diagnose coronary artery disease in patients with suspected CAD without subjecting these patients to invasive coronary angiogram.

Relationship between structural changes in the myocardium of the left atrium and the effectiveness of cryoablation in persistent atrial fibrillation

Introduction. High-resolution contrast-enhanced cardiac magnetic resonance imaging reveals left atrial fibrosis, the severity of which may be related to the effectiveness of catheter ablation.Aim. To study the structural changes of the left atrium myocardium according to magnetic resonance imaging with contrast in patients with persistent atrial fibrillation before balloon cryoablation and compare the results with the effectiveness of the intervention.Materials and methods. The study included 89 patients with persistent form of atrial fibrillation. The patients were randomized into two groups: in the 1st, the pulmonary veins cryoablation was performed (n = 39 (53.4%)); in the 2nd, the pulmonary veins and posterior wall of the left atrium cryoablation was performed (n = 34 (46.6%)). All patients before cryoablation underwent cardiac magnetic resonance imaging with delayed contrast using a high-resolution MR pulse sequence. The clinical efficacy of the intervention was evaluated after 12 months after the cryoablation.Results. The severity of fibrotic myocardial lesion of the left atrium before balloon cryoablation was 0.7% [0; 3,07]. Overall efficiency of the intervention rate was 57.1%. Cryoablation was most effective (59.5%) in patients severity of fibrosis less than 20% and least effective (50%) severity of fibrosis more than 20%. Risk factors for atrial fibrillation recurrence after cryoablation were: early atrial fibrillation recurrence, female sex, the maximum atrial fibrillation duration more than 3 months, stroke/TIA.Conclusion. The severity of left atrial fibrosis more than 20%, early recurrence of atrial fibrillation in the first 3 months after the cryoablation, female sex, the duration of the maximum atrial fibrillation episode more than 3 months, and a history of stroke/transient ischemic attack may be associated with recurrence of AF during the period observation 3–12 months.

Features of myocardial characteristics of patients with acute ST-segment elevation myocardial infarction with diabetes mellitus as assessed by contrast-enhanced cardiac magnetic resonance imaging

Introduction. The presence of diabetes mellitus in patients with acute infarction significantly worsens short- and long-term prognosis, but the features of the course of the infarction in this category of patients have not been fully studied.Objective. To compare clinical, functional and structural myocardial characteristics of patients with acute ST-segment elevation myocardial infarction with and without diabetes mellitus.Materials and methods. The study included 91 patients with revascularized ST-segment elevation myocardial infarction (41 patients with diabetes mellitus). All patients underwent cardiac MRI with contrast, including myocardial T1 mapping, tissue analysis of left ventricular myocardium with determination of infarct zone, heterogeneous zone, edema zone, pre- and post-contrast T1 values, extracellular volume values of healthy myocardium and infarct zone.Results. The presence of diabetes in patients with AMI was associated with increased EDV LV: 153 ± 38 and 181 ± 58 ml (p = 0.007), increased ESV LV: 76 ml [54–93] and 87 ml [71–122] (p = 0.035). Infarct size was significantly larger in patients with diabetes than in those without diabetes: 37 ± 15 g (95% CI: 33–41) and 47 ± 21 g (95% CI: 40–53), p = 0.017. Patients with acute infarction and diabetes mellitus had higher extracellular volume values in both healthy myocardium: 24% [22–27] and 28% [24–30], p = 0.002, and in the infarct zone: 48% [40–58] and 58% [50–61], p = 0.016.Conclusions. In patients with ST-segment elevation myocardial infarction with diabetes mellitus, the infarct size, the edema area, and the value of the extracellular volume fraction both in the infarct area and in the preserved myocardium were larger than in patients without diabetes, which may underlie the development of myocardial dysfunction and further progression of heart failure.

A patient with atrial fibrillation and grade III left atrial spontaneous echo contrast after borreliosis. Case report

In the presented case report, a patient with persistent atrial fibrillation developed due to borreliosis and grade III left atrial spontaneous echo contrast (SEC) according to transesophageal echocardiography, in order to rule out intracardiac thrombosis and concomitant Lyme carditis, contrastenhanced cardiac magnetic resonance imaging was performed. Given the rapid progression of heart failure on the background of tachycardia, the lack of evidence for left atrial appendage thrombosis and myocarditis, electrical cardioversion was performed with the restoration of sinus rhythm and without thromboembolic complications during further follow-up. The issues of the clinical and prognostic significance of SEC, the potential of various diagnostic methods, and the management of such patients are discussed.

Transformative Effect of COVID-19 Pandemic on Magnetic Resonance Imaging Services in One Tertiary Cardiovascular Center.

The aim of study was to investigate the transformative effect of the COVID-19 pandemic on magnetic resonance imaging (MRI) services in one tertiary cardiovascular center. The retrospective observational cohort study analyzed data of MRI studies (n = 8137) performed from 1 January 2019 to 1 June 2022. A total of 987 patients underwent contrast-enhanced cardiac MRI (CE-CMR). Referrals, clinical characteristics, diagnosis, gender, age, past COVID-19, MRI study protocols, and MRI data were analyzed. The annual absolute numbers and rates of CE-CMR procedures in our center significantly increased from 2019 to 2022 (p-value < 0.05). The increasing temporal trends were observed in hypertrophic cardiomyopathy (HCMP) and myocardial fibrosis (p-value < 0.05). The CE-CMR findings of myocarditis, acute myocardial infarction, ischemic cardiomyopathy, HCMP, postinfarction cardiosclerosis, and focal myocardial fibrosis prevailed in men compared with the corresponding values in women during the pandemic (p-value < 0.05). The frequency of myocardial fibrosis occurrence increased from ~67% in 2019 to ~84% in 2022 (p-value < 0.05). The COVID-19 pandemic increased the need for MRI and CE-CMR. Patients with a history of COVID-19 had persistent and newly occurring symptoms of myocardial damage, suggesting chronic cardiac involvement consistent with long COVID-19 requiring continuous follow-up.

Modern approaches to the diagnosis and treatment of cardiac sarcoidosis: results of a cohort study

Aim. To analyze clinical and paraclinical data in patients with documented cardiac sarcoidosis, outlining the key points of diagnosis and selection of the optimal treatment.Material and methods. For the period from 2016 to 2021, 63 patients (50,4±14,1 years) were included in the cohort study on negotiability. Based on a standard examination, 15 patients (41±13 years old) were selected, who continued the examination to confirm the diagnosis of cardiac sarcoidosis. Contrast-enhanced cardiac magnetic resonance imaging (MRI) was performed in 10 patients, while endomyocardial biopsy in 7 patients. All patients underwent 18F-fluorodeoxyglucose positron emission tomography (PET).Results. The most common (53%) electrocardiographic abnormality was right bundle branch block. Ventricular arrhythmias and high-grade atrioventricular block were recorded mainly in patients with documented activity. Regional contractility disorders were predominantly detected in patients with cardiac fibrosis. Delayed contrast enhancement according to cardiac MRI was recorded mainly intramurally in the interventricular septum and subepicardial area of left ventricular (LV) lateral wall. When analyzing the PET results, we found the predominant radiopharmaceutical accumulation in the interventricular septum (56%), lateral (44%) and anterior (33%) LV walls. There was no significant improvement in global LV contractility against the background of immunosuppressive therapy, especially in patients with reduced ejection fraction: initially 49,2±10,1% vs 46,9±14,9% during therapy (p=0,658).Conclusion. A certain apprehensive attitude of the doctor and adherence to the algorithm for early diagnosis of cardiac sarcoidosis allows minimizing the risks of fatal cardiovascular events. On the contrary, in the case of late diagnosis, even the use of aggressive immunosuppressive therapy does not lead to an improvement in global myocardial contractility, and fibrosis zones can cause life-threatening bradyarrhythmias and ventricular arrhythmias.

The Nottingham Ischaemic Cardiovascular Magnetic Resonance resource (NotIs CMR): a prospective paired clinical and imaging scar database—protocol

IntroductionResearch utilising artificial intelligence (AI) and cardiovascular magnetic resonance (CMR) is rapidly evolving with various objectives, however AI model development, generalisation and performance may be hindered by availability of robust training datasets including contrast enhanced images. MethodsNotIs CMR is a large UK, prospective, multicentre, observational cohort study to guide the development of a biventricular AI scar model. Patients with ischaemic heart disease undergoing clinically indicated contrast-enhanced cardiac magnetic resonance imaging will be recruited at Nottingham University Hospitals NHS Trust and Mid-Yorkshire Hospital NHS Trust. Baseline assessment will include cardiac magnetic resonance imaging, demographic data, medical history, electrocardiographic and serum biomarkers. Participants will undergo monitoring for a minimum of 5 years to document any major cardiovascular adverse events. The main objectives include (1) AI training, validation and testing to improve the performance, applicability and adaptability of an AI biventricular scar segmentation model being developed by the authors and (2) develop a curated, disease-specific imaging database to support future research and collaborations and, (3) to explore associations in clinical outcome for future risk prediction modelling studies. ConclusionNotIs CMR will collect and curate disease-specific, paired imaging and clinical datasets to develop an AI biventricular scar model whilst providing a database to support future research and collaboration in Artificial Intelligence and ischaemic heart disease.

Temporal Uncertainty Localization to Enable Human-in-the-Loop Analysis of Dynamic Contrast-Enhanced Cardiac MRI Datasets.

Dynamic contrast-enhanced (DCE) cardiac magnetic resonance imaging (CMRI) is a widely used modality for diagnosing myocardial blood flow (perfusion) abnormalities. During a typical free-breathing DCE-CMRI scan, close to 300 time-resolved images of myocardial perfusion are acquired at various contrast "wash in/out" phases. Manual segmentation of myocardial contours in each time-frame of a DCE image series can be tedious and time-consuming, particularly when non-rigid motion correction has failed or is unavailable. While deep neural networks (DNNs) have shown promise for analyzing DCE-CMRI datasets, a "dynamic quality control" (dQC) technique for reliably detecting failed segmentations is lacking. Here we propose a new space-time uncertainty metric as a dQC tool for DNN-based segmentation of free-breathing DCE-CMRI datasets by validating the proposed metric on an external dataset and establishing a human-in-the-loop framework to improve the segmentation results. In the proposed approach, we referred the top 10% most uncertain segmentations as detected by our dQC tool to the human expert for refinement. This approach resulted in a significant increase in the Dice score (p < 0.001) and a notable decrease in the number of images with failed segmentation (16.2% to 11.3%) whereas the alternative approach of randomly selecting the same number of segmentations for human referral did not achieve any significant improvement. Our results suggest that the proposed dQC framework has the potential to accurately identify poor-quality segmentations and may enable efficient DNN-based analysis of DCE-CMRI in a human-in-the-loop pipeline for clinical interpretation and reporting of dynamic CMRI datasets.

48 A CASE OF RECURRENT VENTRICULAR TACHYCARDIA IN A PATIENT WITH GRANULOMATOSIS WITH POLYANGIITIS WITH A CHALLEGING IDENTIFICATION OF ARRHYTHMIC SUBSTRATE: THE ROLE OF MULTIMODALITY IMAGING

Abstract Background Granulomatosis with polyangiitis (GPA), previously known as Wegener's granulomatosis, is a pulmonary-renal syndrome affecting small and medium sized blood vessels. Cardiac involvement is rare and generally includes pericarditis, myocarditis and aortic valve disease. We report a case of recurrent sustained ventricular tachycardia (VTs) in a patient with GPA. Case summary A 67-year-old man with past medical history of GPA presented palpitations, chest pain and episodes of presyncope. Electrocardiographic tracing upon ED presentation showed sustained monomorphic VT (fig.1) associated with global hypokinesia of the left ventricle and moderately reduced ejection fraction at transthoracic echocardiography (TTE). As the patient was hemodynamically stable, prompt treatment with amiodarone was adopted with successful recovery of sinus rhythm. After a few hours, TTE was normal. However, as troponin I was markedly elevated, coronarography was performed and coronary disease was ruled out. Contrast-enhanced cardiac magnetic resonance imaging (ceCMR) revealed late gadolinium enhancement in basal anteroseptal mid wall, suggestive of myocardial scar tissue with non-ischemic pattern. No sustained ventricular arrhythmias were induced during electrophysiological study (EPS), even with an aggressive protocol (up to 4 extra stimuli and ventricular refractoriness) and electro-anatomical mapping of both ventricles failed to show any arrhythmic substrate. An implantable cardioverter defibrillator (ICD) was then implanted. After 4 months the patient was admitted for multiple episodes of sustained VT (with cycle length in the ICD monitoring window) refractory to drugs and three external defibrillations. Repeated EPS failed to induce sustained arrhythmias. High-density electroanatomical mapping of the right ventricle, however, showed fragmented potentials in the mid-posterior septal wall (fig. 2-3). After myocardial biopsy of the region of interest, radiofrequency catheter ablation of the area was performed with regression of the potentials. The results of endomyocardial biopsy demonstrated fibrosis. At 5 months of follow-up, the patient didn't relapse. Discussion Multimodality imaging is of paramount importance in identifying arrhythmogenic substrate and in characterizing the specific anatomical–functional components of VT circuits. In our patient high-density electroanatomical mapping was able to identify fragmented potentials and define the ablation target area, despite the mismatch with ceCMR.