Assessment of peritoneal tolerance of a new MR blood pool contrast agent in rabbits

Fast 3D MR angiography in conjunction with a new blood pool contrast agent (iron oxide crystals) is a recently described method for detection and localization of intra-abdominal bleeding sites with high sensitivity and specificity. However, peritoneal reactions to the contrast agent have not yet been investigated. The purpose of this study was to assess the peritoneal tolerance of the contrast agent in an animal experiment.

Eleven rabbits were intraperitoneally injected with 5 mL diluted NC100150 Injection; two rabbits were used as the control group. Rabbits injected with NC100150 Injection were imaged in pairs at 12, 24, and 48 hours and 3 weeks, and a single rabbit was imaged at 72 hours and 1 and 2 weeks after the intraperitoneal administration of the agent. Immediately after imaging, the rabbits were killed and an autopsy was performed. Samples of peritoneal surfaces and intra-abdominal organs were harvested for histology. MR imaging, gross pathology, and histology were evaluated.

MR imaging and gross pathology demonstrated the presence of intraperitoneal contrast agent up to 24 hours after administration. Histology revealed a considerable amount of iron in the peritoneum, mesenteric fat, and lymph nodes within the first 24 hours. In most cases, iron was rapidly cleared from these sites within 2 days; in one animal, however, iron was detectable up to 1 week. No signs of inflammation or fibrosis were detected.

This study shows no evidence of inflammatory reactions or signs of fibrosis after the intraperitoneal application of NC100150 Injection.