(CCSP098) THE DIFFERENCE OF SUITABLE INVERSION TIMES FOR LATE GADOLINIUM ENHANCEMENT CARDIAC MAGNETIC RESONANCE IMAGING BETWEEN RIGHT AND LEFT VENTRICLES

Background: Late gadolinium enhancement (LGE) - cardiovascular magnetic resonance imaging (CMR) is an established clinical method for assessing myocardial viability. The success of this method is contingent on choosing an appropriate inversion time (TI) which nulls healthy myocardium and exposes fibrotic tissue with a bright signal intensity (1). Although the right ventricle (RV) is involved in many pathological conditions, the choice of TI is based on the time which nulls the left ventricle (LV) muscle which may be inappropriate to assess fibrosis in the RV (2-3). Our goal was to define differences between RV and LV myocardial TI.

METHODS AND RESULTS: The TI-scout images of patients who underwent a clinically indicated CMR were retrospectively analyzed to identify the appropriate TI of both the RV and LV by two experienced clinical readers. The CMR exams were completed on one of three scanners: a 1.5T Artist(GE Healthcare, Milwaukee, USA), a 3T SIGNA Premier (GE Healthcare, Milwaukee, USA) or a 3T Skyra (Magnetom Skyra™,Siemens Healthineers, Erlangen, Germany). A sub-analysis was conducted on hypertrophic cardiomyopathy (HCM) patients with a thickened RV wall to rule out the influence of partial volume averaging (with the blood pool or epicardial fat) on differences in TI between the RV and LV.

133 patients (mean age = 53.6± 16.9 years, 63.2% male) were enrolled into this study: 73% non-ischemic cardiomyopathy, 23% ischemic cardiomyopathy and 4% non-specific cardiomyopathy.

62% of patients were scanned on the Premier, 21% on the Artist, and 17% on the Skyra. The mean TI for LV and RV signal suppression, respectively, were: 316.9 ± 63.2ms and 284.8 ± 53.3 ms (Artist), 334.4 ± 42.7 ms and 298.8 ± 36.8 ms (Premier), and 293.6 ± 30.2 ms and 255.7 ± 29.8 ms (Skyra). The TI needed to null the LV was significantly higher than the RV in all three scanners (p values: Artist =0.045, Premier < 0.0001, Skrya =0.0001). In the subgroup of HCM patients (n =7,mean age =57.71 ± 10y., 29% female), the LV wall thickness was 14.13 ± 2.81 mm with a mean TI of 329.71 ± 46.63 ms. The RV wall thickness was 4.37± 1.03 mm with mean TI of 298.86 ± 42.53 ms.

Conclusion: This study found that the TI of the RV is lower than that of the LV, suggesting that evaluation of the RV muscle may require selection of TIs independent from LV TI selection.