Tetralogy of Fallot: 3D Velocity-encoded MR Imaging for Evaluation of Right Ventricular Valve Flow and Diastolic Function in Patients after Correction

Purpose: To evaluate three-dimensional (3D) velocity-encoded (VE) magnetic resonance (MR) imaging, as compared with two-dimensional (2D) VE MR imaging, for assessment of pulmonary valve (PV) and tricuspid valve (TV) flow, with planimetry as the reference standard, and to evaluate diastolic function in patients with a corrected tetralogy of Fallot (TOF). Materials and Methods: Local institutional review board approval was obtained, and patients or their parents gave informed consent. Twenty-five patients with a corrected TOF (12 male, 13 female; mean age, 13.1 years +/- 2.7 [standard deviation]; age range, 8-18 years) and 19 control subjects (12 male, seven female; mean age, 14.1 years +/- 2.4; age range, 8-18 years) underwent planimetric MR imaging, 2D VE MR imaging, and 3D VE MR imaging for TV and PV flow evaluation. For evaluation of diastolic function, PV and TV flow were summated. Data were analyzed by using linear regression analysis, paired and unpaired t testing, and Bland-Altman plots. Results: Strong correlations between the 2D VE MR and 3D VE MR measurements of PV flow (for forward flow: r = 0.87, P < .01; for backward fl ow: r = 0.97, P < .01) were observed. With PV effective fl ow as a reference, 3D TV effective fl ow measurements were more accurate than 2D TV effective fl ow measurements: In patients, the mean 2D TV effective fl ow versus 2D PV effective fl ow difference was 17.6 mL +/- 11 (P < .001), and the mean 3D TV effective fl ow versus 3D PV effective fl ow difference was - 1.2 mL +/- 4.7 (P = .22). Diastolic functional impairment in patients could be detected at 3D VE MR imaging diastolic assessment. Conclusion: Three-dimensional VE MR imaging is accurate for PV fl ow assessment and is more accurate than 2D VE MR imaging for TV fl ow evaluation. Assessment of diastolic function with 3D VE MR imaging can facilitate ongoing research of diastolic dysfunction in patients with a corrected TOF.