Three-dimensional Feature Tracking Cardiac Magnetic Resonance in Hypertrophic Cardiomyopathy: Comparison with Two-Dimensional Algorithm

Abstract Aim The aims of this study were to: 1) determine whether 2D and 3D feature tracking cardiac magnetic resonance (FT-CMR) are equivalent in patients with hypertrophic cardiomyopathy (HCM), 2) compare 3D FT-CMR values in HCM and healthy volunteers and 3) compare FT-CMR in most frequent HCM phenotypes. Methods Consecutive patients with HCM and LVEF>55% were included in the study. FT-CMR parameters included left ventricular (LV) global longitudinal (GLS), circumferential (GCS) and radial (GRS) strain, which were calculated using both 2D and 3D FT-CMR derived from multi-slice 2D cine image stacks in the LV short and long axis plane. FT was calculated using Circle Cvi42 software. Results Sixty HCM patients (66.7% male, mean age 58.2 ± 15.8 years) were included (56.7% septal HCM, 25% apical HCM). FT analysis was feasible in all individuals. Seventy-two percent of patients exhibited focal fibrosis in 2 [0-4] segments. As previously reported for healthy individuals, myocardial strain evaluated using 3D FT-CMR was consistently lower compared to 2D FT-CMR. The highest level of agreement was noted between the 2D and 3D values of GCS, with a mean difference of -0.3% (95% CI -1.81 to 1.2, p=0.68), while GRS showed the lowest agreement. In patients with apical HCM GLS 3D was significantly more reduced than in patients with septal HCM (-7.4% ± 4.1 vs. -10.5% ± 2.9, p=0.004). Conclusions 3D FT-CMR is feasible in HCM patients. 3D FT is advantageous as it does not require additional scanning time, making it suitable for HCM patients with limited acoustic window and abnormal geometry.