Cardiac MRI: T2-Mapping Versus T2-Weighted Dark-Blood TSE Imaging for Myocardial Edema Visualization in Acute Myocardial Infarction

Abstract

Purpose: To assess the diagnostic accuracy of T2 mapping for the detection of myocardial edema in acute myocardial infarction (AMI), and to compare this diagnostic accuracy with that of the current standard for myocardial edema imaging, which is T2w dark-blood TSE imaging.

Materials and Methods: 29 patients with AMI were examined at 1.5 T. For the visualization of myocardial edema, T2 maps, calculated from three T2w SSFP images, and T2w dark-blood TSE images were acquired in standard short- and long-axis views. Cine SSFP images were acquired for the analysis of left ventricular (LV) function and late gadolinium enhancement images (LGE) for the visualization of myocardial necrosis. The T2 maps as well as the T2w dark-blood TSE images were evaluated twice independently from the cine SSFP and LGE images. The presence or absence of myocardial edema was rated visually for each LV segment. As the standard of reference, the infarct zone was defined based on the cine SSFP and the LGE images.

Results: In this segment-based analysis, T2 mapping showed a sensitivity of 82 % and a specificity of 94 % for the detection of edema in the infarct zone. T2w dark-blood TSE imaging revealed a sensitivity of 50 % and a specificity of 98 %. T2 mapping showed a higher intra-rater agreement compared to T2w dark-blood TSE imaging (κ: 0.87 vs. 0.76).

Conclusions: T2 mapping allows for the visualization of myocardial edema in AMI with a high sensitivity and specificity, and features better diagnostic accuracy in terms of a higher sensitivity compared to T2w dark-blood TSE imaging.

Citation Format:

• Naßenstein K, Nensa F, Schlosser T et al. Cardiac MRI: T2-Mapping Versus T2-Weighted Dark-Blood TSE Imaging for Myocardial Edema Visualization in Acute Myocardial Infarction. Fortschr Röntgenstr 2014; 186: 166 – 172

Zusammenfassung

Ziel: Ziel der vorliegenden Studie war es, zu untersuchen mit welcher diagnostischen Genauigkeit das T2-Mapping die Visualisierung eines Myokardödems beim akuten Myokardinfarkt (AMI) erlaubt und diese diagnostische Genauigkeit mit der des gegenwärtigen Standards für die myokardiale Ödembildgebung (T2-gewichtete, dark-blood präparierte TSE-Sequenz) zu vergleichen.

Material und Methoden: 29 Patienten mit AMI wurde bei 1,5 T untersucht. Zur Ödemdarstellung wurden T2-Maps, welche aus jeweils 3 unterschiedlich T2-gewichteten SSFP-Bildern berechnet wurden, sowie T2-gewichtete dark-blood TSE Bilder in Standardkurz- und Langachsenschichten akquiriert. Zur Analyse der regionalen linksventrikulären (LV) Funktion wurden cine SSFP, zur Darstellung der Myokardnekrosen Late Gadolinium Enhancement (LGE) Bilder akquiriert. Die T2-Maps sowie die T2w-dark-blood-TSE-Datensätze wurden zweimal unabhängig von den übrigen Sequenzen visuell ausgewertet, wobei pro LV-Segment analysiert wurde ob ein Ödem sichtbar ist oder nicht. Basierend auf den cine SSFP und LGE-Bildern wurde die Infarktzone als Referenzstandard festgelegt.

Ergebnisse: Das T2-Mapping zeigte in dieser segmentbasierten Analyse eine Sensitivität von 82 % und eine Spezifität von 94 % für die Detektion eines Ödems in der Infarktzone; die T2w-dark-blood-TSE-Sequenz eine Sensitivität von 50 % und einer Spezifität von 98 %. Das T2-Mapping zeigte im Vergleich zur T2w-dark-blood-TSE-Sequenz eine höhere Interrater-Reliabilität (κ: 0,87 vs. 0,76).

Schlussfolgerung: Das T2-Mapping erlaubt die Visualisierung des Myokardödems beim AMI mit hoher Sensitivität und Spezifität und weist aufgrund einer höheren Sensitivität eine bessere diagnostische Genauigkeit als die T2w-dark-blood-TSE-Sequenz auf.

Key words

heart - MR imaging - T2 mapping - myocardial infarction

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