| ObjectiveTo investigate the relationship between longitudinal relaxation time(T1mapping),extracellular volume(ECV)and late gadolinium enhancement(LGE)in patients with hypertrophic cardiomyopathy(HCM).MethodsA total of 56 patients with HCM who underwent magnetic resonance imaging(MRI)at 3.0 T from March 2018 to June 2019 in the Department of Radiology,Fuwai Central China Hospital were retrospectively collected.The scanning sequence included cine sequence,T1 mapping,first-pass perfusion,delayed enhancement and enhanced T1 mapping.Thirty healthy volunteers were scanned at the same time,and the scanning sequence included cine sequence and T1 mapping.Cine sequence,myocardial perfusion and delayed enhancement of cardiac morphology were observed,and 16 segments of left ventricular myocardium(except apex)were analyzed according to the American Heart Association(AHA)segmentation method to measure the maximum left ventricular wall thickness at the end of diastole and the initial myocardial T1 value of all myocardial segments in the HCM group and the control group;the T1 value and ECV value of each segment were measured after enhancement in the HCM group.Differences in data between HCM groups and between HCM and normal controls were analyzed with ANOVA.ResultsThere were 405 hypertrophic segments in 56 patients in the HCM group,including273 hypertrophic and enhanced segments.Hypertrophy unenhanced segment 132,non-hypertrophic segment 491,non-hypertrophic and enhanced segments15,non-hypertrophic and unenhanced segment 476.In the control group,there were 480 segments in total in 30 cases,and no hypertrophy was observed in all segments.The end-diastolic left ventricular wall thickness(21.01 mm±4.42 mm),myocardial mass(235.49 g±96.63 g),and initial T1 mapping value(1260.21 ms±66.47 ms)in the HCM group were greater than those in the normal control group(8.41 mm±1.23 mm),(110.01g±22.36 g),and(1195.28 ms±37.48 ms),and the differences were statistically significant(P<0.01).T1 mapping of non-hypertrophic and enhanced segments was 1347.61 ms±38.63 ms,with an ECV value of 44.37±7.38,and T1 mapping of hypertrophic and enhanced segments was 1336.61 ms±47.66 ms,with an ECV value of 42.70±7.88,and T1 mapping of hypertrophic unenhanced segments was 1270.43 ms±37.81 ms,with an ECV value of34.45±7.85.T1 mapping of non-hypertrophic and unenhanced segments was 1212.30ms±37.33 ms,and ECV value was 29.20±4.54.The initial T1 value and ECV value of non-hypertrophic enhanced segments were greater than that of hypertrophic enhanced segments than that of hypertrophic unenhanced segments than that of non-hypertrophic unenhanced segments,and the initial T1 value of non-hypertrophic unenhanced segments was greater than that of normal controls(1195.28 ms±37.48 ms)(P<0.05).The enhanced T1 value of non-hypertrophic enhanced segments(458.98 ms±44.31 ms)was smaller than that of hypertrophic enhanced segments(465.96 ms±43.04 ms)and that of hypertrophic unenhanced segments(527.70 ms±35.79 ms)and that of non-hypertrophic unenhanced segments(576.83 ms±25.84 ms)(P<0.05).There were 138 LGE segments with mild enhancement,86 with moderate enhancement,and 51 with severe enhancement.Among them,t1 mapping value of severe enhancement is 1352.63ms±47.82 ms,ECV value is 45.36±7.92,t1 mapping value of moderate enhancement is 1302.63ms±43.66 ms,ECV value is 39.76±7.31,t1 mapping value of light enhancement is 1282.63ms±47.82 ms,ECV value is 37.39±6.34.The initial T1 value and ECV value of the severe enhanced segment were higher than those of the moderate enhanced segment and those of the mild enhanced segment(P<0.05).The T1 value of severe enhancement(425.98ms±36.04ms)was less than that of moderateenhancement(462.38ms±41.04ms)and that of mild enhancement(513.98ms±42.32ms)(P<0.05).ConclusionThere was a positive correlation between t1 mapping and ECV of cardiac MRI and delayed enhancement;Cardiac MRI t1 mapping and ECV can detect early myocardial fibrosis in HCM and quantitatively assess the histological features of HCM myocardium. |
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