Carboxymethyldextran-A2-Gd-DOTA enhancement patterns in the abdomen and pelvis in an animal model

The aim of this study was to assess MR signal enhancement patterns of carbo xymethyldextran (CMD)-A2-Gd-DOTA, a new macromolecular contrast agent, in t he abdomen and pelvis of New Zealand white rabbits. Nine New Zealand white rabbits underwent MRI before and following injection of 0.05 mmol/kg body w eight (bw) CMD-A2-Gd-DOTA (52.1 kDa), using turbo FLASH-, dynamic FLASH 60 degrees-, T1- and T2-weighted spin-echo and turbo spin-echo sequences up to 10 days p.i. Changes in blood and tissue signal intensities (Delta SI) and relaxation rates (Delta R1) were calculated. Differences between pre- and post-contrast MRI data were compared using the Scheffe test. CMD-A2-Gd-DOTA demonstrated significant blood-pool enhancement and significant tissue enh ancement on T1-weighted images, whereas no significant signal changes were observed on T2-weighted images (P < 0.05). Kidney parenchyma, pelvis and bl adder demonstrated a subsequent enhancement, resembling renal elimination o f the majority of the contrast agent. Liver parenchyma demonstrated a slow, delayed decay of the contrast enhancement due to storage and biodegradatio n of larger subfractions of the contrast agent. All tissue signal intensiti es were back to baseline 10 days p.i. CMD-A2-Gd-DOTA is a new macromolecula r contrast agent with blood-pool effect, significant signal enhancement of abdominal organs and pelvic bone marrow, partial storage in the liver and b aseline tissue signal intensities by 10 days p.i.