INFERIOR PETROSAL SINUS - IMAGING-ANATOMIC CORRELATION

PURPOSE: To correlate computed tomographic (CT) or magnetic resonance (MR) images with dissections of normal inferior petrosal sinuses (IFS) . MATERIALS AND METHODS: Postmortem dissection was performed in 12 ind ividuals, one of whom had undergone CT and MR imaging 3 months before death. Seven patients underwent IFS venography, CT, and MR imaging. On e hundred sixteen patients with normal IFS underwent MR imaging; 40, C T and MR imaging; and two, CT, MR imaging, and arteriography. RESULTS: Images showed that the IFS and basilar plexus formed conspicuous, enh anced structures that provide much of the border between the clivus an d cerebrospinal fluid. Axial, cross-sectional IFS dimensions were as l arge as 9 x 16 mm. The larger sinuses were contained by deep grooves o f bone that sometimes showed marked cortical thinning. Sixty-nine (39% ) of the 175 individuals studied had markedly asymmetric IFS. CONCLUSI ON: CT and MR images showed that normal IFS and basilar plexus vary in size and are frequently asymmetric. This range of normal measurements and appearances should be taken into account before abnormalities in this region are diagnosed.