A preliminary study of MR T₁ mapping for detection of left ventricular myocardial fibrosis in hypertrophic cardiomyopathy

Objective: To investigate the diagnostic values of T₁ mapping 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 T₁ mapping 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 T₁ value 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 T₁ value (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, all P < 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, all P < 0.01), between peri-LGE and halo-like LGE and typical patchy LGE (t = 6.12 and 39.90, respectively, both P < 0.01), between halo-like LGE and typical patchy LGE (t = 25.63, P < 0.01). ROC curves indicated that T₁ mapping imaging has a greater area under the curve than that of traditional LGE imaging (0.974 ± 0.050 vs. 0.751 ± 0.180). Conclusion: T₁ mapping imaging can be a useful method to evaluate the severity of the fibrosis, especially at the early stage. (authors)