Pre-operative evaluation with MR in tetralogy of fallot and pulmonary atresia with ventricular septal defect

Purpose: To assess whether MR imaging could replace angiography in pre operative evaluation of patients with tetralogy of Fallot and pulmonary atresia with ventricular septal defect (VSD), especially since the surgical correction was done earlier than was previously the rule. Material and Methods: Fourteen patients with tetralogy of Fallot (n=10) or pulmonary atresia with VSD (n=4), mean age 7.5+/-4.4 months, were evaluated with angiocardiography and MR before definitive surgical correction. Results: There was good diagnostic agreement between the two modalities when evaluating right ventricular outflow obstruction; 86% for valvular and 93% for supravalvular stenosis, but the agreement was somewhat lower for the subvalvular obstruction (57%). Surgery findings, however, were in favour of MR in 5 patients concerning the subvalvular right ventricular outflow tract obstruction. MR images identified all stenoses in the right and left pulmonary arteries, but overlooked one stenosis in the main pulmonary artery. MR could evaluate patency in all palliative shunts. Conclusion: Even in this young age group, MR imaging offers a good alternative to angiocardiography for the pre-operative evaluation of the right ventricular outflow tract, the main pulmonary artery and the proximal right and left pulmonary arteries, before definitive surgical correction of tetralogy of Fallot and pulmonary atresia with VSD.