USEFULNESS OF MRI FOR THE PREOPERATIVE EVALUATION OF THE PULMONARY-ARTERIES IN TETRALOGY OF FALLOT

Adequate pre-operative evaluation of patients with Tetralogy of Fallot (TF) includes cine-angiography to delineate the pulmonary vasculature and the coronary artery anatomy and to demonstrate the presence of mu ltiple ventricular septal defects (VSDs), All other information is obt ained from color-Doppler-echocardiography, Magnetic resonance imaging (MRI), using the spin-echo sequence and cine-angiography was employed on 18 patients with TF, four of whom had aorto-pulmonary shunts. Mean age at MRI was 12.9 m (SD 2.3 m) and 14.3 m (SD 2.8 m) at cine-angiogr aphy, To compare MRI and cine-angiography we measured the ascending ao rta, the main, the left and right pulmonary arteries and each structur e at three levels, Diagnostic agreement between the two imaging method s was found if, for each modality, one of the three measurements in on e structure differed by more than 40% from the other two measured in c ase of a local stenosis, and the diameter of the main pulmonary artery was less than 60% of the aorta to diagnose hypoplasia of the main pul monary artery, There was close agreement between cine-angiography and MRI. With regard to the intracardiac anatomy, MRI was superior to colo r-Doppler-echocardiography in the depiction of aortic override and of right ventricular hypertrophy. In three cases local stenoses in the pu lmonary arteries were detected by MRI and cine-angiography, Hypoplasia of the main pulmonary artery was detected by MRI in six patients and by cine-angiography in five patients. Cine-angiography missed one case of hypoplasia, In the remaining 11 patients normal findings were foun d by MRI and cine-angiography. For the demonstration of shunts, gradie nt-recalled-echo MRI is expected to give better results than the spin- echo sequence which depicted two out of four shunts in this series, Ci ne-angiography can be substituted by MRI in delineating the pulmonary arteries, New developments in MRI indicate the feasibility of delineat ing the coronary arteries. (C) 1997 Elsevier Science Inc.