The effect of intracranial surgical trauma on gadolinium-enhanced magnetic resonance imaging.

Gadolinium-enhanced magnetic resonance imaging (MRI) is currently the gold standard for diagnosis of an acoustic neuroma. Its status is diagnosis of a recurrent or residual neuroma is not nearly as clear. A pilot study of 36 postoperative cases showed enhancement in 100% of the patients at the operative site. To examine the role of surgical trauma and biodegradable packing on enhanced MRI, an animal study was designed. Cats and monkeys that underwent posterior fossa surgical procedures had preoperative and postoperative MRI and histologic correlation of any enhanced area. Areas of postoperative enhancement should not be considered as diagnostic of tumor. Further studies are necessary to develop a criteria for recurrent tumor diagnosis with enhanced MRI.