Impact of Basal Plane Selection on the Evaluation of Cardiac Performance Parameters with Cardiac Magnetic Resonance Imaging in Patients with Corrected Tetralogy of Fallot: A Systematic Approach

Background: Assessment of cardiac performance parameters in patients with corrected tetralogy of Fallot with cardiac MRI short axis method compromises critical elements including papillary muscles, determination of end-diastolic and end-systolic cardiac phase, and furthermore, selection of the basal plane. Objectives: The study purpose was to evaluate the impact of basal plane selection on resulting cardiac performance parameters in cardiac MRI. Patients and Methods: Cardiac MRI examinations of 26 patients (mean-age: 20.7 years 7.8) with corrected tetralogy of Fallot were analyzed retrospectively. In post-processing, selection of end-diastolic and end-systolic phase was performed manually by visual determination of largest/smallest ventricular cavities. End-diastolic volume, end-systolic volume, and stroke volume were then calculated for both ventricles. Afterward, initially selected basal planes were systematically varied by one slice, and resulting volumes were compared. This retrospective study was conducted under approval of the institutional review board without patient informed consent. Results: Variations of the basal plane caused significant changes (P < 0.005) of end-diastolic and end-systolic volumes. Differences were as large as 15.2% 5.8 regarding the left ventricle and up to 17.4% 6.1 for the right ventricle. Consequently, calculated stroke volume changed up to 19.2% 6.3 for the left and 22.7% 7.2 for the right ventricle. Ejection fractions of both ventricles varied significantly (P < 0.005). These differences were up to 19.1% 8.2. Conclusion: Variation of the basal plane by just one slice in cardiac MRI short axis method led to significant changes in the resulting cardiac performance parameters of both ventricles in patients with corrected tetralogy of Fallot.