Imaging study of the long extracranial extension of the inferior petrosal sinus with MSCT

The aim of this study was to explore the anatomic route of Long‐Inferior Petrosal Sinuses (IPS) with multi‐slice spiral computed tomography, and to provide referenced evidence for the interventional preoperative evaluation for the diagnosis and treatment of skull base and sellar lesions. The route of Long‐IPS and its confluence with the internal jugular vein (IJV) and the connection level of 12 IPS were shown with multi‐planar reconstruction and curved multi‐planar reconstruction, and the IPS length was determined. Combining the results of continuous multi‐slice scanning, the diameters of the IPS at the initial segment in the jugular foreman and middle segment and the confluence segment of the IPS‐IJV junction level were determined. The mean length of the Long‐IPS was 66.2 ± 17.5 mm, and the length was over 60 mm on eight sides and its peak value 100 mm. The mean diameters of the IPS were 2.4 mm ± 0.7 mm, 2.1 mm ± 0.4 mm, and 2.1 mm ± 0.5 mm at the initial, middle, and confluent segments, respectively. Their diameters were equal to or greater than 2 mm at the connection level on eight sides. Furthermore, the diameter was greater than 1.6 mm at the middle and initial segments. The Long‐IPS might be used as a route to the intra‐cranial IPS. MSCT is helpful for showing the route and variation of the IPS and could be an effective method for preoperative evaluation of the IPS. Clin. Anat. 23:160–167, 2010. © 2009 Wiley‐Liss, Inc.