Evaluation of pulmonary artery anatomy using magnetic resonance: the importance of multiplanar and oblique imaging.

Pulmonary artery anatomy was studied in 36 patients (age range 12 days to 12.83 years, mean 2.9 years) with right ventricular outflow tract obstruction over a 3-year period using a 1.5 Tesla Magnetic Resonance system. Gated spin-echo sequences were obtained in each patient. Image planes used were straight and oblique transverse, oblique coronal, and oblique sagittal. The studies were analyzed retrospectively and comparative angiographic, surgical, and postmortem data was available in all cases. As previously noted with other imaging modalities, multiple views and oblique cuts were found to increase significantly the quality and accuracy of the information acquired. In 12 of the 15 patients who had axial and coronal imaging of both branch pulmonary arteries, the pulmonary arteries were unequivocally demonstrated to at least the first hilar branch. However, early in our experience we missed a number of branch stenoses that developed following surgical anastomoses. These mistakes were caused by inadequate or inappropriate slice acquisition. Magnetic resonance is an important technique for imaging pulmonary arteries. Careful use of the appropriate imaging planes is essential for accurate demonstration of the anatomy.