Elisa McAlindon

Quantification of infarct size and myocardium at risk

Aims The aim of this study was to evaluate seven methods for quantifying myocardial oedema [2 standard deviation (SD), 3 SD, 5 SD, full width at half maximum (FWHM), Otsu method, manual thresholding, and manual contouring] from T2-weighted short tau inversion recovery (T2w STIR) and also to reassess these same seven methods for quantifying acute infarct size following ST-segment myocardial infarction (STEMI). This study focuses on test–retest repeatability while assessing inter- and intraobserver variability. T2w STIR and late gadolinium enhancement (LGE) are the most widely used cardiovascular magnetic resonance (CMR) techniques to image oedema and infarction, respectively. However, no consensus exists on the best quantification method to be used to analyse these images. This has potential important implications in the research setting where both myocardial oedema and infarct size are increasingly used and measured as surrogate endpoints in clinical trials. Methods and results Forty patients day 2 following acute reperfused STEMI were scanned for myocardial oedema and infarction (LGE). All patients had a second CMR scan on the same day >6 h apart from the first one. Images were analysed offline by two independent observers using the semi-automated software. Both oedema and LGE were quantified using seven techniques (2 SD, 3 SD, 5 SD, Otsu, FWHM, manual threshold, and manual contouring). Interobserver, intraobserver and test–retest agreement and variability for both infarct size and oedema quantification were assessed. Infarct size and myocardial quantification vary depending on the quantification method used. Overall, manual contouring provided the lowest inter-, intraobserver, and interscan variability for both infarct size and oedema quantification. The FWHM method for infarct size quantification and the Otsu method for myocardial oedema quantification are acceptable alternatives. Conclusions This study determines that, in acute myocardial infarction (MI), manual contouring has the lowest overall variability for quantification of both myocardial oedema and MI when analysed by experienced observers.

Measurement of myocardium at risk with cardiovascular MR: comparison of techniques for edema imaging.

PURPOSE To determine variability and agreement for detecting myocardial edema with T2-weighted short-tau inversion recovery (STIR), acquisition for cardiac unified T2 edema (ACUT2E), T2 mapping, and early gadolinium enhancement (EGE) after successfully reperfused ST-segment-elevation myocardial infarction (STEMI) and diagnostic accuracy of each sequence to predict infarct-related artery (IRA). MATERIALS AND METHODS Local ethics committee approved the study, with patient informed written consent. On day 2 after successful primary angioplasty for STEMI, 53 patients were prospectively enrolled; 40 patients (mean age, 60 years) completed study. Two sets of cardiac magnetic resonance (MR) images were obtained on same day 6 hours apart. Basal, midcavity, and apical sections were obtained with each sequence. Interobserver, intraobserver, and interimage variability (1 minus intraclass correlation coefficient) and agreement (Bland-Altman method) were assessed. RESULTS Size of myocardial edema significantly differed. Mean size of myocardium at risk was similar between T2-weighted STIR (18.2 g) and T2 mapping (17.3 g) (P = .54). Mean size differed between T2-weighted STIR (18.2 g) and ACUT2E (14.0 g) (P = .01) and between T2-weighted STIR (18.2 g) and EGE (14.2 g) (P = .003). T2 mapping and EGE had best agreement (interobserver bias: T2-weighted STIR, -0.9 [mean difference] ± 9.6 [standard deviation]; ACUT2E, -2.5 ± 6.9; T2 mapping, -3.8 ± 4.7; EGE, -5.3 ± 5.9; interimage bias: T2-weighted STIR, 1.5 ± 5.8; ACUT2E, -0.8 ± 4.9; T2 mapping, 3.1 ± 4.0; EGE, 1.1 ± 4.9; intraobserver bias: T2-weighted STIR, 1.4 ± 5.8; ACUT2E, 0.6 ± 4.7; T2 mapping, 2.2 ± 3.1; EGE, 1.7 ± 2.9). Variability was lowest for T2 mapping (intraobserver, 0.05; interobserver, 0.09; interimage, 0.1) followed by EGE (intraobserver, 0.03; interobserver, 0.14; interimage, 0.14), with improved detection of territory of IRA versus ACUT2E (intraobserver, 0.11; interobserver, 0.22; interimage, 0.12) and T2-weighted STIR (intraobserver, 0.1; interobserver, 0.32; interimage, 0.1). CONCLUSION Cardiac MR methods to detect and quantify infarct myocardial edema are not interchangeable; T2 mapping is the most reproducible method, followed by EGE, ACUT2E, and T2-weighted STIR. Clinical trial registration no. NCT01468662

Diagnosing Cardiac Involvement in the Hypereosinophilic Syndrome by Cardiac Magnetic Resonance

Hypereosinophilic syndrome is characterized by unexplained hypereosinophilia involving different organ systems. The investigators present a patient diagnosed with hypereosinophilic syndrome in which cardiac magnetic resonance was pivotal in establishing the presence of cardiac involvement.

Stress CMR as a gatekeeper to complete revascularisation in STEMI patients with moderate-severe bystander disease at primary percutaneous coronary intervention

Background Nearly 40% of the patients presenting with ST Elevation Myocardial Infarction (STEMI) have multivessel disease (MVD). Currently ESC and the ACC/AHA guidelines recommend revascularization of the culprit artery only. 2 recent trials (PRAMI and CVLPRIT) have shown a superiority of complete in-hospital revascularisation as compared to culprit only treatment. Although the mortality in the 2 groups in the trials were not significantly different but the composite end point was, which was mainly driven by ischaemia.

Formal consensus to identify clinically important changes in management resulting from the use of cardiovascular magnetic resonance (CMR) in patients who activate the primary percutaneous coronary intervention (PPCI) pathway

Objective To define important changes in management arising from the use of cardiovascular magnetic resonance (CMR) in patients who activate the primary percutaneous coronary intervention (PPCI) pathway. Design Formal consensus study using literature review and cardiologist expert opinion to formulate consensus statements and setting up a consensus panel to review the statements (by completing a web-based survey, attending a face-to-face meeting to discuss survey results and modify the survey to reflect group discussion and completing the modified survey to determine which statements were in consensus). Participants Formulation of consensus statements: four cardiologists (two CMR and two interventional) and six non-clinical researchers. Formal consensus: seven cardiologists (two CMR and three interventional, one echocardiography and one heart failure). Forty-nine additional cardiologists completed the modified survey. Results Thirty-seven draft statements describing changes in management following CMR were generated; these were condensed into 12 statements and reviewed through the formal consensus process. Three of 12 statements were classified in consensus in the first survey; these related to the role of CMR in identifying the cause of out-of-hospital cardiac arrest, providing a definitive diagnosis in patients found to have unobstructed arteries on angiography and identifying patients with left ventricular thrombus. Two additional statements were in consensus in the modified survey, relating to the ability of CMR to identify patients who have a poor prognosis after PPCI and assess ischaemia and viability in patients with multivessel disease. Conclusion There was consensus that CMR leads to clinically important changes in management in five subgroups of patients who activate the PPCI pathway.

134 Incremental Value of Cardiovascular Magnetic Resonance Imaging in Patients Surviving non Traumatic out of Hospital Cardiac Arrest: A Tertiary UK Centre Experience

Background Non-traumatic out of hospital cardiac arrest (OOHCA) is one of the leading causes of death in western world. Acute coronary syndrome (ACS) is the most common aetiology of OOHCA with a culprit artery lesion identified on invasive angiography. However, 1/3rd of patients with OOHCA have unobstructed coronaries on angiography. Non-invasive tissue characterisation by cardiovascular magnetic resonance (CMR) has the potential to establish the final diagnosis in patients with OOHCA with obstructed coronaries as well as with unobstructed coronary arteries. Methods We retrospectively reviewed the database in our tertiary cardiothoracic centre from October 2009 to November 2013. We identified 54 consecutive patients who were referred for a CMR following an OOHCA. A comprehensive CMR protocol with cine, oedema and scar imaging was used. All scans were done within 6–8 weeks of the index event and was reported by a consultant with >10years of experience in CMR. Results Out of the 54 patients (16 female, age range 21–84 years), 29 (54%) had coronary artery disease, in which the culprit was treated by primary angioplasty and 25 (46%) patients had unobstructed coronaries. Of the latter, 3 had hypertrophic cardiomyopathy, 4 had myocarditis or cardiac sarcoid, 2 had non-ischaemic dilated cardiomyopathy, 2 had LV non-compaction (LVNC) cardiomyopathy, 7 had nonspecific abnormalities and 9 had completely normal CMR scan. In all patients (n = 29) with significant CAD on angiography CMR identified a myocardial infarction (100%). So in total, 40/54 (74%) of OOHCA, a cause was found on CMR. In 11/25 (44%) of OOHCA with unobstructed coronaries a diagnosis was made whereas in 9/25 (36%), a normal CMR was suggestive of a primary arrhythmic cause, thereby guiding further therapy (ICD). Conclusions In adults surviving a non-traumatic OOHCA with unobstructed coronaries on angiogram, CMR could identify the underlying aetiology in the large majority of cases. This has potential implications for treatment and prognosis.

Evaluation of 7 techniques for the quantification of myocardial oedema in STEMI

Background Myocardial oedema is a consequence of injury during ST segment elevation myocardial infarction (STEMI). T2 weighted short tau inversion recovery (T2w STIR) is widely used for oedema assessment on CMR. No consensus exits for which threshold/ contouring method should be used for the quantification of the area of myocardial oedema as a surrogate endpoint in clinical trials. This study investigates the inter- and intra- observer and interscan reproducibility of 7 techniques in use for oedema assessment (2 SD, 3S D, 5S D, FWHM, Otsu, manual threshold and manual contouring). The aim was to determine the most robust method for the quantification of myocardial oedema STEMI. Methods 20 patients day 2 following acute reperfused STEMI were assessed. All patients had 2 CMR scans on the same day at least 6 hours apart. These CMRs included a full short axis stack (8mm slice thickness) of T2w STIR. Images were analysed offline using CMR 42 software (Circle CVI). The endocardium and epicardium were delineated on each slice. For 2, 3 and 5 SD a region of interest was drawn in the remote myocardium, deemed unaffected with the absence of RWMA or LGE. In addition a ROI was drawn in the high signal intensity myocardium in the affected myocardium for the FWHM technique. Manual thresholding was subjective as was manual contouring. The myocardial oedema was expressed as a % of LV. The difference between techniques was assessed using a 1 way ANOVA. The inter-, intra-observer and inter-scan agreement was assessed using the Bland Altman method. Variability was calculated as 1- intraclass correlation coefficient (ICC). Results There is a significant difference in the % of LV with myocardial oedema between all 7 techniques used (p<0.001). 5SD produced the smallest volume of myocardial oedema (8.7 % LV +/- 6.6), FWHM the largest (59.8 % LV +/- 15.9). Manual contouring provided the best inter-, intra- observer and best inter-scan agreement using Bland Altman, with lowest variability (Figure 2). Manual thresholding had the worst agreement. Conclusions This study supports the manual contouring method as the most robust for quantification of myocardial oedema as a surrogate endpoint in clinical trials. The Otsu method provided good agreement between observers

Native T1 mapping to detect extent of acute and chronic myocardial infarction: comparison with late gadolinium enhancement technique

Investigate whether native-T1 mapping can assess the transmural extent of myocardial infarction (TEI) thereby differentiating viable from non-viable myocardium without the use of gadolinium-contrast in both acute and chronic myocardial infarction (aMI and cMI). Sixty patients (30 cMI > 1 year and 30 aMI day 2 STEMI) and 20 healthy-controls underwent 1.5 T CMR to assess left ventricular function (cine), native-T1 mapping (MOLLI sequence 5(3)3, motion-corrected) and the presence and TEI from late gadolinium enhancement (LGE) images. Segments with TEI > 75% was considered non-viable. Gold-standard LGE-TEI was compared with corresponding segmental native-T1. Segmental native-T1 correlated significantly with TEI (R = 0.74, p < 0.001 in cMI and R = 0.57, p < 0.001 in aMI). Native-T1 differentiated segments with no LGE (1031 ± 31 ms), LGE positive but viable (1103 ± 57 ms) and LGE positive but non-viable (1206 ± 118 ms) in cMI (p < 0.01). It also differentiated segments with no LGE (1054 ± 65 m), LGE positive but viable (1135 ± 73 ms) and LGE positive but non-viable (1168 ± 71 ms) in aMI (p < 0.01). ROC analysis demonstrated excellent accuracy of native-T1 mapping compared to LGE-TEI (AUC − 0.88, p < 0.001 in cMI, vs AUC − 0.83, p < 0.001 in aMI). Native-T1 performed better in cMI than aMI (p < 0.01). In cMI a segmental T1 threshold of 1085 ms differentiated viable from non-viable segments with a sensitivity 88% and specificity of 88% whereas a T1 of 1110 ms differentiated viable from nonviable with 79% sensitivity and 79% specificity in aMI. Native-T1 mapping correlates significantly with TEI thereby differentiating between normal, viable, and non-viable myocardium with distinctive T1 profiles in aMI and cMI. Native T1-mapping to detect MI performed better in cMI compared to aMI due to absence of myocardial oedema. Native-T1 mapping holds promise for viability assessment without the need for gadolinium-contrast agent.

TCT-184 Early changes in circulating miRNA 133a are indicative of cardiac remodelling after 3 months in patients presenting with acute ST elevation myocardial infarction

METHODS A total, 1,519 consecutive patients (pts) who admitted with AMI from April 2004 to April 2014 were enrolled in this study. Anemia was defined as a hemoglobin concentration on admission of <13 g/dL for men and <12 g/dL for women. We divided patients into 4 groups according to gender and age: male and younger group (group 1), male and elderly group (group 2), female and younger group (group 3) and female and elderly group (group 4). Long-term cumulative mortality was evaluated among the 4 groups.

Remote myocardium is also affected in acute myocardial infarction: evidence from advanced CMR relaxometry

Methods 30 patients (mean age 61 ± 10years and 70% males) with STEMI and successful revascularisation by percutaneous coronary intervention were included. Each subject underwent clinical CMR at 1.5 T with T2 and T1 mapping (MOLLI) pre and post contrast (equilibrium contrast technique for extracellular volume (ECV) quantification) within 48hours of presentation. The T2 and pre and post contrast T1 values were evaluated in each of the 16 AHA myocardial segments.