RT Journal Article
SR Electronic
T1 CT of Extraarachnoid Metrizamide Instillation
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 689
OP 692
VO 7
IS 4
A1 Michael D. Dake
A1 William P. Dillon
A1 Robert H. Dorwart
YR 1986
UL http://www.ajnr.org/content/7/4/689.abstract
AB Because CT of spinal extraarachnoid metrizamide collections may be misleading, we reviewed the postmetrizamide CT scans of 425 patients in order to characterize the appearance of subdural or epidural metrizamide. Eight patients were found to have extraarachnoid metrizamide contrast collections. In all patients, both the subarachnoid space and the extraarachnoid collection were opacified with metrizamide. In seven patients, a subdural collection of metrizamide created a mass upon the opacified subarachnoid space. Three of these subdural collections were less dense than the opacified subarachnoid compartment and simulated soft-tissue disease, including tumor and an arteriovenous malformation. The hypodense collections are probably a result of leakage of metrizamide and cerebrospinal fluid through the spinal needle defect. CT clues for diagnosing these potentially misleading subdural collections include preservation of the normal dural and epidural interface, identification of small islands of metrizamide within a suspected soft-tissue “mass,” the presence of concomitant epidural contrast material collections, and the absence of adjacent vertebral-body destruction.