Radiology, Vol 196, 239-244, Copyright © 1995 by Radiological Society of North America
Experimental gastrointestinal hemorrhage: detection with contrast- enhanced MR imaging and scintigraphy
H Gupta, R Weissleder, AA Bogdanov Jr and TJ Brady
Department of Radiology, Massachusetts General Hospital, Boston 02114, USA.
PURPOSE: To examine the use of O-methoxy poly(ethylene)glycol-O'-
succinyl-N-epsilon-poly(L-lysyl) gadolinium diethylenetriaminepentaacetic
acid (MPEG-PL-Gd-DTPA) as a potential magnetic resonance (MR) angiographic
contrast agent for the detection of gastrointestinal (GI) bleeding.
MATERIALS AND METHODS: MPEG-PL-Gd- DTPA was used for blood pool
enhancement, and MPEG-PL-technetium-99m DTPA was used for planar nuclear
imaging studies. GI bleeding was tested in rats by controlled injection of
contrast material-doped blood through a jejunostomy catheter. MR imaging
was performed at 1.5 T. RESULTS: Ideal flip angle, used with a spoiled
gradient-echo pulse sequence, was 40 degrees. The smallest amount of
hemorrhage detected at MR imaging was 0.05 mL; at nuclear imaging it was
0.02 mL. With the superior spatial resolution of MR imaging, individual
loops of contrast material-filled bowel were identified and bleeding points
were pinpointed. CONCLUSION: GI hemorrhage can be easily detected at MR
imaging if a long circulating macromolecular contrast agent is used to
decrease the T1 of extravasated blood.
