Quantitative T1 Mapping for Detecting Microvascular Obstruction in Reperfused Acute Myocardial Infarction: Comparison with Late Gadolinium Enhancement Imaging

Fig. 1. MVO within infarcted myocardium on LGE image, native T1 map, and post-contrast T1 map. A. On LGE image, MVO is observed as hypo-enhanced region within hyper-enhanced infarcted myocardium. B. On native T1 map, MVO is distinguished as dark region within bright infarcted myocardium. C. On post-contrast T1 map, MVO is identified as bright region within dark infarcted myocardium. Regions of interest, in which T1 values were measured in (B) and (C), were outlined with circles in infarcted and remote myocardium and with contour of MVO. LGE = late gadolinium enhancement, MVO = microvascular obstruction

Fig. 2. MVO areas in 20 patients on LGE images, 18 patients on native T1 maps, and 10 patients on post-contrast T1 maps. Boxes, 1st–3rd quartiles; bold lines, medians; whiskers, minimum and maximum values.

Fig. 3. Bland-Altman plots showing comparison of MVO areas between image types. A. Mean difference in MVO area between LGE images and native T1 maps was 9.8% (n = 18, 95% CI: −11.5–31.0%), and coefficient of repeatability (2 SDs) was 83.8%. B. Mean difference in MVO size between LGE images and post-contrast T1 map images was 51.9% (n = 10, 95% CI: 22.2–81.6%), and coefficient of repeatability (2 SDs) was 81.4%. CI = confidence interval, SD = standard deviation

Fig. 4. T1 values of infarcted myocardium, MVO, and remote myocardium on native T1 maps (n = 18) and post-contrast T1 maps (n = 10). A. On native T1 maps, mean T1 value of MVO was lower than that of infarcted myocardium, but was not statistically different from that of remote myocardium. B. On post-contrast T1 maps, mean T1 value of MVO was significantly higher than that of infarcted myocardium, but significantly lower than that of remote myocardium. Boxes, 1st–3rd quartiles; bold lines, medians; whiskers, minimum and maximum values; o, outliers. *outliers.