VASCULAR-PERMEABILITY TO SODIUM FLUORESCEIN IN THE RABBIT CRANIAL NERVE ROOT - POSSIBLE CORRELATION WITH NORMAL CRANIAL NERVE ENHANCEMENT ON GADOLINIUM-ENHANCED MAGNETIC-RESONANCE-IMAGING

Vascular permeability in cranial nerve roots was examined after intrav enous injection of sodium fluorescein in the adult rabbit. Fluorescenc e was observed in the distal nerves through the following portions: in tracavernous portion of the oculomotor nerve, distal internal auditory canal segment of the facial nerve, and ganglionic portions of the tri geminal, glossopharyngeal and vagus nerves. In the acoustic nerve, sho wed fluorescence. No fluorescence was observed in the olfactory or opt ic nerves. During in vivo gadolinium-enhanced magnetic resonance imagi ng (Gd-MRI) of two separate animals, trigeminal nerve enhancement was observed in the region showing fluorescence. Histologically, intense f luorescence was observed in ganglia and external nerve sheaths of the cranial nerves showing macroscopic fluorescence. A slight fluorescence was also seen in endoneurial connective tissue but not observed withi n the nerve fibers. The results of this study suggest that the physiol ogical enhancement of human cranial nerves seen on Gd-MRI may correlat e with vascular permeability.