A preliminary study of MR T1mapping for detection of left ventricular myocardial fibrosis in hypertrophic cardiomyopathy

Objective To investigate the diagnostic values of T1mapping imaging for evaluating myocardial fibrosis in patients with hypertrophic cardiomyopathy (HCM). Methods Forty-eight subjects with HCM and 18 healthy volunteers underwent conventional late gadolinium enhancement (LGE) MR imaging and T 1mapping imaging.According to the characteristics of LGE,the myocardium in HCM was divided into remote area of LGE,peri-LGE,LGE (halo-like LGE and typical patchy LGE).The changing rates of contrast-enhanced T1value of these regions were measured and compared with normal volunteers' myocardium.The Chi-square test,pairwise comparison and ROC curve were used for statistical analysis. Results The changing rate of T1value (CRT) in healthy volunteers was no significant difference from that in the remote area of LGE (3.98±3.19 vs.3.36±2.77,t=0.98,P>0.05).There were significant differences in CRT between healthy volunteers' myocardium and the peri-LGE (13.51±5.67),halo-like LGE (17.70±5.57) and typical patchy LGE (36.62±8.03,t=15.28,17.13 and 47.48,respectively,allP<0.01),between remote area-LGE and peri-LGE,halo-like LGE and typical patchy LGE (t=19.64,20.76 and 56.64,respectively,allP<0.01),between peri-LGE and halo-like LGE and typical patchy LGE (t=6.12 and 39.90,respectively,bothP<0.01),between halo-like LGE and typical patchy LGE (t=25.63,P<0.01).ROC curves indicated that T 1mapping imaging has a greater area under the curve than that of traditional LGE imaging (0.974±0.050 vs.0.751±0.180). Conclusion T1mapping imaging can be a useful method to evaluate the severity of the fibrosis,especially at the early stage. Key words: Cardiomyopathy,hypertrophic; Endomyocardial fibrosis; Magnetic resonance imaging; Image enhancement