Results of contrast-medium supported 3D MR angiography in respiratory arrest after optimisation of contrast medium bolus.

Purpose: Reduction of the contrast material volume by optimised bolus administration during a breath-hold 3D MR angiography and its clinical value. Materials and methods: Breath-hold ultrafast 3D gadolinium-enhanced MR angiography (T-R 5 ms, T-E 2 ms, FA 20 degrees) of the thoracic and abdominal aorta was performed in 50 patients and correlated with an i.a. DSA. 25 patients (group I)were examined with a contrast material volume of 40 mi Cd-DTPA and three successive acquisitions at fixed intervals (25, 53 and 81 s) after start of the contrast material injection. Another group of 25 patients (group 2) received only 20 mi Gd-DTPA and the start of the MR acquisition was determined individually by prior evaluation of the contrast material transit times after injection of a test bolus. The signal-to-noise (S/N) and contrast-to-noise (GIN) ratios were compared and a subjective image quality rating (0-3) by three reviewers was achieved in both groups. Results: A total of 37 vascular pathologies were correctly detected by MR angiography compared to i.a. DSA. The grading of stenoses was overestimated in some cases. The S/N and C/N were higher in group 2 (63.2 and 50.1) than in group 1 (58.0 and 38.9). The subjective ratings also showed better results in group 2 (2.76) than in group 1 (2.20). Conclusion: The ultrafast gadolinium-enhanced 3D MR angiography allowed a reliable visualisation of the thoracic and abdominal aorta and its branches in a single breath-hold. An optimised examination with a reduced contrast material volume can be achieved by an individual adaptation of the MR acquisition to contrast material administration after measurement of the contrast material transit times.