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‐held three‐dimensional magnetic resonance angiography (3D‐MRA) sequence. Dynamic SH U 555 A‐enhanced 3D‐MRA studies were performed in 20 patients with focal liver lesions. Sequential coronal 3D‐MRA‐FISP scans were acquired (TR 5.0 msec, TE 2.0 msec, flip angle 250, 140 × 256 matrix, and 80 mm slab) within 15 seconds. Scanning was started immediately after bolus injection of 10μmol Fe/kg bodyweight and was repeated at multiple time points (baseline and 30, 60, 90, 120, 180, 240, 300, 360, and 420 seconds). Signal intensity values of liver, focal liver lesions, spleen, the portal venous system, the abdominal aorta, and the inferior vena cava were obtained to calculate relative enhancement (ENH = [SI post ‐ SI pre]/SI pre × 100). Visibility 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 555 A is clinically feasible, and significant vessel enhancement can be achieved even at the dose of 10μmol Fe/kg bodyweight. However, further refinements are required to improve contrast effects.J. Magn. Reson. Imaging 1999;10:65–71. © 1999 Wiley‐Liss, Inc.