T1-mapping and extracellular volume in patients with hypertrophic cardiomyopathy without focal myocardial injury in late gadolinium enhancement sequence

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background The LGE (late gadolinium enhancement) sequence is a recognized classic tool for imaging focal myocardial injury. The T1-mapping sequence to assess native T1 myocardial time, post-contrast T1 time, and myocardial extracellular volume (ECV) is a widely studied tool for imaging focal and diffused myocardial injury. Purpose The aim of the study was to evaluate the native T1 time, the post-contrast T1 time and the myocardial extracellular volume in the T1-mapping sequence in patients with hypertrophic cardiomyopathy without focal LGE myocardial injury. Methods The study group consisted of 28 consecutive patients who met the criteria for diagnosis of hypertrophic cardiomyopathy without focal LGE myocardial injury (HCM group; mean age 52.17 ± 6.35 years). 28 patients without cardiomyopathy (CON group; mean age 51.76 ± 6.49 years) with similar anthropometric parameters were selected by the case-to-case method as a control group. All patients underwent 1.5 T cardiac magnetic resonance, including cinematographic sequences (CINE), LGE sequence and T1-mapping sequences before (native) and 20-minutes after intravenous administration of a paramagnetic agent (post-contrast). In the T1-mapping sequences, the mean T1 time of the whole myocardium (T1 whole myocardium) was assessed, as well as the T1 time in the basal layers (T1 basal), middle layers (T1 middle) and apical layers (T1 apical) of the myocardium. Moreover, the mean T1 time was assessed in the 16-segment myocardial AHA model (T1 segment 1-16). The extracellular volume of the myocardium was estimated in an analogous way. Results In CINE sequences, in the HCM group compared to the CON group, the end-diastolic thickness of the anterior part of interventricular septum, the end-diastolic thickness of the left ventricular posterior wall and the left ventricular mass index were significantly higher. The studied groups did not differ in left ventricular ejection fraction. In both groups, no foci of myocardial injury in the LGE sequence were found. There were no statistically significant differences in T1 times between the study groups. In the HCM group as compared to the CON group, the ECV whole myocardium, ECV basal, ECV apical and ECV segments 1-3, 8, 13-16 were statistically significantly higher. Conclusion Patients with hypertrophic cardiomyopathy without myocardium focal injury in the LGE sequence are characterized by higher myocardial ECV values, assessed in the T1-mapping sequence.