[Distal pulmonary vessels demonstration by magnetic resonance angiography and its usefulness in the diagnosis of peripheral nodules].

To evaluate the usefulness of MRA in the diagnosis of peripheral pulmonary nodules, 18 lung cancers and 12 old inflammatory nodules were studied employing multiplanar fast radiofrequency spoiled gradient echo sequence (SPGR) with phased array coils. For each case, 12 images in coronal and sagittal sections were obtained after administration of Gd-DTPA, and original images, maximum intensity projection (MIP) images and multiplanar reconstruction (MPR) images were used for the interpretation. In ten cases, MRA images were compared with resected specimens and we found that the minimum diameter of pulmonary vessels which could be demonstrated by our method was about 1.5mm. As the results of the interpretation of MRA images in 30 cases, venous involvement, which is one of the classical important findings indicative of malignancy, was clearly demonstrated in 15 of 18 (83%) lung cancers, whereas such involvement was detected in only 3 of 12 (25%) inflammatory nodules. Pulmonary MRA, especially MIP and MPR images could make it easy to identify involved vessels, and proved to be useful in differentiating pulmonary nodules.