MR CISTERNOGRAPHY - INITIAL EXPERIENCE IN 41 CASES

PURPOSE: To present our initial experience with MR cisternography, an application of fast spin-echo MR with fat suppression, and compare it with routine MR cranial studies in the evaluation of the subarachnoid cisterns and their contents. METHODS: MR cisternography is a heavily T 2-weighted fast spin-echo technique with high spatial resolution; it u ses fat suppression and video reversal of the images. A small number o f individual sections (two to four) are compressed into a composite im age by a maximum-intensity projection algorithm, providing better depi ction of anatomy in three dimensions. MR cisternography enhances the s ignal intensity of the cerebrospinal fluid (CSF) with suppression and subtraction of the background. A total of 41 patients were examined du ring a period of 6 months. MR cisternography was performed as an addit ional one (n = 31) or two (n = 10) sequences after conventional MR stu dy. RESULTS: Twenty-one cases of disease were examined by MR cisternog raphy, including 8 neoplasms, 4 CSF fistulas, and 3 large intracranial aneurysms. MR cisternography provided information unavailable by conv entional MR studies in 17 cases. These included visualization of fistu lous tracks in patients with CSF rhinorrhea, origin of a large suprase llar aneurysm, an additional loculus of a posterior fossa aneurysm and its relation to surrounding structures, and proper location of three tumors (intraaxial versus extraaxial). Clear depiction of the pituitar y gland separate from the cavernous sinus was noted in 60% of the case s, and a new observation of a CSF sleeve around the third nerve in the posterior cavernous sinus was made in 85% of the cases. CONCLUSION: M R cisternography is superior to conventional MR studies in depicting a natomic structures within the subarachnoid spaces. This technique is r ecommended in the evaluation of cranial CSF fistulas and suprasellar a nd posterior fossa masses and in diagnosis of intraaxial versus extraa xial location of intracranial tumors.