GD-DTPA MR DETECTION OF BLOOD-BRAIN-BARRIER OPENING IN RATS AFTER HYPEROSOMOTIC SHOCK

Objective: Detection of blood-brain barrier (BBB) opening in neonates has required invasive methods not clinically applicable. We set out to develop a noninvasive approach to detect such opening. Materials and Methods: Wistar rats were studied using MRI with Gd-DTPA contrast befo re and after injection of hyperosmotic solutions known to produce barr ier opening. Arabinose was given via right carotid artery to produce u nilateral barrier opening; urea was given via tail vein to produce bil ateral opening; controls received normal saline. Next, all animals rec eived Gd-DTPA via tail vein. Results: Animals receiving carotid hypero smotic injections showed increased signal in the ipsilateral brain hem isphere; those receiving venous hyperosmotic injections showed increas ed signal bilaterally. Similar increases were not found prior to admin istration of hyperosmotic agent or in saline controls. In both cases. barrier opening was detectable using the relative partitioning of Gd-D TPA between intrabarrier and extrabarrier structures, even in the abse nce of a hemispheric control. Conclusion: We conclude that MRI with Gd -DTPA contrast allows noninvasive detection of BBB opening in the rat.