Angiografia con Risonanza Magnetica del corpo con mezzo di contrasto: Esperienza con apparecchio da 0,5 tesla

Introduction. We optimized the technique of contrast-enhanced Magnetic Resonance Angiography (MRA) with a .5 T superconductive magnet. Material and methods. Forty patients with normal blood pressure and heart rate gave their informed consent to MRA studies with contrast agent administration. The carotid arteries were studied in 10 patients, the pulmonary arteries in 10, the thoracic aorta in 10 and the abdominal aorta and renal arteries in 10. All the examinations were performed with a .5 T superconductive magnet (Philips T5) acquiring 3D T1-weighted GE sequences with contrast agent administration. The parameters were; TR/TE/FA 13 ms/4 ms/60°; 256×256 MA; 2 mm slice thickness; 1 NEX. The contrast agent was administered with an automatic injector (.2 mmol/kg at 1.5 flowrale) after a bolus test to evaluate circulation time. The images were studied by a radiologist rating artery visualization as "good" or "poor" on a multiple choice card. The signal-to-noise ratio was evaluated using regions of interest positioned on the examined vessels (signal) and muscles (noise). Results. The mean start delay was 12.2 s for the abdominal aorta, 10.3 s and 8.7 s for the thoracic aorta and pulmonary arteries, and 10.3 for the carotid arteries. Fifty-eight of 70 vessels were well visualized and 12 were poorly visualized. The signal-to-noise ratio exceeded 1 in all districts. Conclusions. Our experience shows that enhanced MRA provides diagnostic images of body arteries, even at .5 T.