Anatomical study of the occipital sinus using contrast-enhanced magnetic resonance venography.

The frequency and anatomical features of the occipital sinus (OS) were analyzed in this study by contrast-enhanced magnetic resonance venography (MRV) with enhanced fast gradient echo three-dimensional (EFGRE3D) and we discuss the clinical usefulness of this method. The study included 555 patients who underwent contrast-enhanced MRV with EFGRE3D, and maximum intensity projection (MIP), multiplanar reformation (MPR) and multiprojection volume reconstruction (MPVR) images were obtained for the regions of interest. The frequency, size and communication of the OS with other vessels were assessed. The OS was identified in 209 of the 555 patients (37.7%). There were no statistically significant sex-related differences. The OS was observed less frequently in subjects younger than 50 years. Cranially and/or caudally, some OS were separated and communicated with multiple vessels. In five patients, the straight sinus (StS) communicated directly with the OS and not with the other sinuses; in two patients, the StS communicated with veins other than the OS only via small anastomotic veins. Many morphological differences in the OS can be seen. In addition, some OS function as the main drainage route of the intracranial veins instead of the transverse sinus or sigmoid sinus. In addition to MIP, detailed examination by MPR and MPVR is required for the preoperative evaluation of posterior cranial fossa lesions.