Fully Automated, MRI-based Left-Ventricular Contractility Analysis in Breast Cancer Patients Following Chemotherapy

Abstract

This study investigated if measurements of mechanical contractile parameters, such as strains, torsion and left-ventricular ejection fraction (LVEF), are indicative of left-ventricular (LV) remodeling that may occur in patients who have been exposed to the anthracycline and trastuzumab type of chemotherapeutic agents (CA). An equally important goal was investigating this contractility using a single-scan cardiac strain analysis tool comprising of the Displacement Encoding with Stimulated Echoes (DENSE) sequence for MRI scans and the Radial Point Interpolation Method (RPIM). Data was acquired in 11 patients who had been exposed to CA agents and were under either a regimen of breast cancer antineoplastic drugs and/or were being treated for cardiac complications. A Bland-Altman analysis of interobserver strain measurements showed agreements of 0.01 ± 0.06 for longitudinal strain, 0.10 ± 1.92° for torsion. Enlarging of the LV in the patient population was indicated by a significant difference in their diastolic diameters in healthy subjects. Significant longitudinal strains differences were seen between patients and healthy subjects which were 0.15 ± 0.03 vs 0.21 ± 0.04 (p=0.02) and 0.17 ± 0.02 vs 0.22 ± 0.03 (p=0.01) for the mid-ventricular and apical sections. A similar result for torsion was found between patients and healthy subjects for the mid-ventricular and basal sub-regions. The results from the statistical analysis show the likelihood of LV remodeling and fibrosis in these patients that is otherwise not indicated by LVEF measurements.