MAGNETIC-RESONANCE CISTERNOGRAPHY FOR VISUALIZATION OF INTRACISTERNALFINE-STRUCTURES

Object. To assess its usefulness in demonstrating cisternal anatomy, t he authors investigated magnetic resonance (MR) cisternography in whic h a heavily T-2-weighted turbo spin-echo method was used to visualize normal anatomical fine structures and lesions in the basal cisterns in 20 healthy volunteers and 43 patients. The authors applied peripheral pulse,eating, which had been optimized to reduce artifacts in the cis terns attributable to cerebrospinal fluid (CSF) flow. Methods. The det ectability of each cranial nerve was determined in healthy volunteers. The first, second, and third nerves and the seventh-eighth nerve comp lex were clearly visualized in all participants; the fifth nerve was c learly seen in 80% and the sixth cranial nerve in 50%. The fourth nerv e and the ninth through 12th nerves were difficult to identify individ ually, except in some volunteers. To reduce artifacts caused by fast C SF flow, we determined the delays as a function of the time elapsed be tween two consecutive peaks of pulse wave in a peripheral pulse gate ( P-P interval) at which there was reversal of flow direction to minimiz e the CSF flow-related artifact. Using peripheral pulse gating and a t ime delay of 30% of the R-R interval, the authors succeeded in minimiz ing the CSF flow-related artifacts. Magnetic resonance cisternography appears to be very useful for demonstrating intracisternal fine anatom y and enhancing the contours of the juxtacisternal lesion. A minute am ount of CSF interposed between lesions and normal structures such as n erves, vessels, or bone structures can be detected by means of this se quence. In patients with facial spasm, axial images and oblique corona l images obtained in a plane parallel to the seventh-eighth cranial ne rve complex demonstrated vascular compression in all 13 patients. The MR cisternography finding of compression was confirmed in all nine pat ients who underwent microvascular decompression. Conclusions. Magnetic resonance cisternography appears to show great promise for evaluation of patients with neurovascular compression or tumors in and around th e basal cisterns; the procedure adds only a small amount of imaging ti me.