Objective: Our goal was to evaluate the clinical utility of pulmonary 3D TOF MRA using a contrast medium and breath holding.
Materials and methods: To determine an optimal imaging time in a pilot study, 30 sequential axial images were obtained for each of 18 patients by using a turbo fast low angle shot sequence immediately after a bolus injection of 5 ml Gd-DTPA. MRA consisted of five sequential MR scans performed using a 3D fast imaging with steady-state precession sequence on 13 patients. The imaging start time after a bolus injection of 10 ml Gd-DTPA was determined from the results of the pilot study. We hoped that the acquisition of the center of k-space of the first MRA was matched to the period of maximum effect of the first pass bolus for the pulmonary arteries.
Results: In a pilot study on average, pulmonary artery signal intensities were relatively high from 10.4 to 20.7 s after the contrast medium injection. The MR angiograms obtained at the optimal time were superior to those that followed. All pulmonary trunks and the right and left main pulmonary arteries were accurately recognized. MRA had a sensitivity of 80.0%, a specificity of 95.0%, and an accuracy of 94.5% for the detection of segmental artery stenosis or occlusion. Abnormal vessels were visualized in both patients with pulmonary sequestration.
Conclusion: Pulmonary 3D TOF MRA using breath holding and a contrast medium is useful in demonstrating proximal pulmonary vasculature and pulmonary sequestration.