Diagnostic value of T1- and T2-weighted 3-Tesla MRI for postmortem detection and age stage classification of myocardial infarction.

The aims of this study are to retrospectively evaluate the diagnostic value of T1- and T2-weighted 3-T magnetic resonance imaging (MRI) for postmortem detection of myocardial infarction (MI) in terms of sensitivity and specificity and to compare the MRI appearance of the infarct area with age stages. Postmortem MRI examinations (n = 88) were retrospectively reviewed for the presence or absence of MI by two raters blinded to the autopsy results. The sensitivity and specificity were calculated using the autopsy results as the gold standard. A third rater, who was not blinded to the autopsy findings, reviewed all cases in which MI was detected at autopsy for MRI appearance (hypointensity, isointensity, hyperintensity) of the infarct area and the surrounding zone. Age stages (peracute, acute, subacute, chronic) were assigned based on the literature and compared with the age stages reported in the autopsy reports. The interrater reliability between the two raters was substantial (κ = 0.78). Sensitivity was 52.94% (both raters). Specificity was 85.19% and 92.59%. In 34 decedents, autopsy identified an MI (peracute: n = 7, acute: n = 25, chronic: n = 2). Of 25 MI classified as acute at autopsy, MRI classified peracute in four cases and subacute in nine cases. In two cases, MRI suggested peracute MI, which was not detected at autopsy. MRI could help to classify the age stage and may indicate the area for sampling for further microscopic examination. However, the low sensitivity requires further additional MRI techniques to increase the diagnostic value.

Patient-Specific Cardiac Magnetic Resonance Feature Tracking Approach for Scar Detection in Concomitant Ischemic and Non-Ischemic Heart Disease.

Aim: This study investigated a patient-specific approach of using cardiac magnetic resonance (CMR) feature tracking for scar detection in a heterogenous patient group with chronic ischemic and non-ischemic heart disease. Methods: CMR exams of 89 patients with concomitant chronic ischemic and non-ischemic heart disease (IHD+) as well as 65 patients with ischemic scars only (IHD) were retrospectively evaluated. In all patients, global (GCS) and segmental circumferential strain (SCS) was derived from native cine images using a dedicated software (Segment CMR, Medviso). After calculation of patient-specific median GCS (GCSmedian), segmental values from GCSmedian percentage plots were correlated with corresponding myocardial segments in late gadolinium enhancement (LGE). Results: Overall GCS ranged between -3.5% to -19.8% and average GCS was lower in IHD+ than in IHD (p <0.05). In IHD, 19% of all myocardial segments were infarcted, in IHD+ 16.6%. Additionally, non-ischemic LGE was present in 6.7% of segments in IHD+. Correlation of GCSmedian percentage plots with corresponding LGE showed that presence of ischemic scar tissue in a myocardial segment was very likely below a cut-off of 39.5% GCSmedian (87.5% sensitivity, 86.3% specificity, AUC 0.907, 95% CI 0.875-0.938, p < 0.05). Conclusion: In patient-specific GCSmedian percentage plots calculated from native cine images, ischemic scar tissue can be suspected in myocardial segments below the threshold of 40% GCSmedian (sensitivity 88%, specificity 86%), even in a heterogenous patient cohort with ischemic and non-ischemic heart disease.