DuraSeal magnetic resonance and computed tomography imaging: Evaluation in a canine craniotomy model

OBJECTIVE: Several novel sealing materials have been proposed as an adjunct to sutured dural closure to help insure watertight closure, thus diminishing the risk of pseudomeningocele formation. This evaluation was undertaken to clarify the in vivo magnetic resonance imaging (MRI) and computed tomographic (CT) scan characteristics of one such sealant, which has a high water content, permitting similar imaging characteristics to pseudomeningoceles and inflammatory collections. METHODS: After a craniotomy in two canine subjects, we sprayed a novel, water-soluble, self-polymerizing, absorbable, hydrogel sealant onto the dura and the bone flap was replaced. After recovery, both animals underwent MRI and CT scans after 3 days and again at 2, 4, 6, 8, and 10 weeks after the craniotomy. The appearance of the gel at each timepoint was characterized and compared with the macroscopic and microscopic findings obtained 14 weeks after implantation. RESULTS: Both animals remained neurologically intact. Hydrogel sealant was readily apparent with all imaging techniques through Week 6. Diagnostic distinction from inflammatory collections and pseudomeningoceles was possible with MRI, using inversion recovery and contrast-enhanced sequences; such distinctions were occasionally challenging with a contrast-enhanced CT scan. Temporal absorption of the gel and subsequent closure of the remaining void was documented. Histopathology showed minimal changes, and excellent tissue compatibility of the gel was noted. CONCLUSION: The hydrogel sealant can be observed with cross sectional imaging and can be distinguished from cerebrospinal fluid using a CT scan, complemented by an occasional MRI scan. In addition, complete absorption of the hydrogel, with closure of the remaining void was noted. Histological examination found an unremarkable response with no neurotoxicity or space-filling defect.