Abstract 2337: Left Ventricular Strain and Twist in Patients with Tetralogy of Fallot: A Gradient-Echo Cine MRI Study
Background: We analyzed myocardial tissue strain and twist in patients with post-op tetralogy of Fallot (TOF) to evaluate myocardial performance with a novel MRI analysis method adapted for tracking features in MR gradient-echo loops.
Methods: We studied 30 patients after surgery for TOF (age 6mo-7yrs) and 15 healthy young adults (age 24–35 years). All patients underwent cardiac MRI for evaluation of TOF or as healthy controls. All MRI images were acquired with a Philips 3T Magnet with segmented gradient-echo cine-loop sequences (short and long axis stacks) to cover the left ventricle. All gradient-echo cine-loop images were analyzed as DICOM files offline by a Vector Velocity Imaging method (VVI; Siemens) which had been developed for tracking ultrasound speckle features.
Results: LV myocardial circumferential strain in the control group was measured at 19% to 26% with highest values in the septal and inferior area (26% ± 6%) and lower values at the anterior free wall area (20% ± 4%). While in patients with TOF/post repair loss of septal strain (9% to 15%) was observed along with septal dyssynchrony, no gradient in strain measures could be found between the septum/inferior wall and anterior free wall area. Healthy adults showed a counterclockwise LV twist of 6° to 14° (mean 7° ± 4°) with twisting starting in the septal area, while all TOF patients showed a marked decrease is LV twisting to 2° to 7° (mean 4° ± 3°) and loss of septal twist initiation.
Conclusions: Adapting VVI for gradient-echo MR provides evaluation of MR strain and twist, and in our study demonstrated that septal dysfunction exists in patients post repair TOF.