Contrast-enhanced 3D-MRA of the upper abdomen with a bolus-injectable SPIO(SH U 555 A)

The purpose of this study was to study temporal changes in signal intensity of liver, spleen, abdominal vessels, and focal liver lesions following iv bolus injection of a superparamagnetic iron oxide (SPIO) using a breath-hel d three-dimensional magnetic resonance angiography (3D-MRA) sequence, Dynam ic SH U 555 A-enhanced 3D-MRA studies were performed in 20 patients with fo cal liver lesions. Sequential coronal 3D-MRA-FISP scans were acquired (TR 5 .0 msec, TE 2.0 msec, nip angle 25 degrees, 140 x 256 matrix, and 80 mm sla b) within 15 seconds. Scanning was started immediately after bolus injectio n of 10 mu mol Fe/kg bodyweight and was repeated at multiple time points (b aseline and 30, 60, 90, 120, 180, 240, 300, 360, and 420 seconds). Signal i ntensity values of liver, focal liver lesions, spleen, the portal venous sy stem, the abdominal aorta, and the inferior vena cava were obtained to calc ulate relative enhancement (ENH = [SI post- SI pre]/SI pre x 100). Visibili ty of vessels was assessed by consensus of two readers. Signal enhancement within abdominal vessels peaked during the first pass; however, significant signal enhancement was still present 420 seconds following injection, The liver and the spleen also demonstrated a biphasic enhancement pattern with prolonged parenchymal enhancement. Dynamic MRA with bolus injectable SH U 5 55 A is clinically feasible, and significant vessel enhancement can be achi eved even at the dose of 10 mu mol Fe/kg bodyweight, However, further refin ements are required to improve contrast effects. J. Magn, Reson, Imaging 19 99;10:65-71. (C) 1999 Wiley-Liss, Inc.