[Determination of optimal technical factors for the single breath-hold pulmonary MR angiography and its clinical applications].

To optimize pulmonary MR angiography for the noninvasive evaluation of pulmonary vasculature, six healthy volunteers were examined using the fast radiofrequency spoiled gradient echo sequence (Fast SPGR) and standard body coil of a commercial 1.5T MR imaging system. The examinations by 2D Fast SPGR were performed under various TR, flip angles and slice thicknesses within the time of a single breath hold, and those by 3D Fast SPGR were performed under various flip angles and slab thicknesses. The most satisfactory results were obtained by 2D Fast SPGR with the parameters of TR 60 msec, TE 2.1 msec, flip angle 20 degrees slice thickness 10 mm, FOV 30-40 cm, matrix 256 x 192 and NEX1. For 3D Fast SPGR, TR 10 msec, TE 1.9 msec, flip angle 10 degrees, slab thickness 60mm (12 partitions), FOV 30-40 cm, matrix 256 x 128 and NEX1 were best. Concomitant injection of Gd-DTPA provided higher resolution of peripheral vessels. The MIP images showed pulmonary vasculature with resolution of vessels beyond 4 th order branches in 2D Fast SPGR and 5 th order branches in 3D Fast SPGR. 3D Fast SPGR with contrast enhancement was applied to patients with primary lung cancer in the hilum, malignant mediastinal tumor, pulmonary embolism, pulmonary arteriovenous fistula, pulmonary varix, and round atelectasis. Pulmonary MR angiography is considered to be a noninvasive and effective method not only for the evaluation of the tumor invasion to the central pulmonary vessels but also for the demonstration of other pulmonary vascular pathology.