CT blood pool enhancement in primates with lopromide-carrying liposomes containing soy phosphatidyl glycerol.

RATIONALE AND OBJECTIVES

The purpose of this study was to determine the feasibility of using iodinated liposomes as blood pool agents for computed tomography (CT) in nonhuman primates.

MATERIALS AND METHODS

Five normal adult baboons (15-21 kg) were anesthetized and intravenously injected with iopromide containing soy phosphatidyl glycerol liposomes with a diameter of 195 nm. Each animal received a dose of 300 mg total iodine per kilogram (46% encapsulation).

RESULTS

The animals tolerated the injections well, experiencing no measurable electrocardiographic changes, and recovered uneventfully from anesthesia. Sequential helical CT scans of the baboons from the base of the skull to the symphysis pubis acquired up to 40 minutes after injection showed persistent blood pool enhancement. Maximum mean enhancement of major vascular structures was 106 HU at 1 minute after contrast medium injection. Mean blood pool enhancement was 76, 72, and 67 HU at 10, 20, and 40 minutes after injection, respectively. Liver and spleen were enhanced by 40 and 41 HU, respectively, 40 minutes after injection. No significant enhancement was measured in the brain and pancreas.

CONCLUSION

Soy phosphatidyl glycerol with iopromide liposomes produces prolonged vascular enhancement and has potential as a blood pool CT contrast agent in primates.