Bridging veins of the cerebellum: a magnetic resonance imaging study

Purpose To date, no study has yet explored the bridging veins (BVs) of the cerebellum using neuroimaging modalities. Therefore, this study aimed to characterize them using magnetic resonance imaging (MRI). Methods A total of 90 patients with intact cerebellar hemispheres and intracranial dural sinuses underwent thin-sliced, contrast-enhanced MRI. Results The BVs were classified into six routes based on the draining pattern into the dural sinuses. The superior vermian vein emptying into the straight sinus was delineated in 100% of the patients. The inferior vermian vein emptying into the confluence of the sinuses was identified in 66.7% of the patients. The inferior hemispheric and cerebellar cortical veins emptying into the transverse sinus were identified in 54.4% and 26.7% of the patients, respectively. The inferior vermian and cerebellar cortical veins emptying into the straight sinus were identified in 77.8% and 12.2% of the patients, respectively. The cerebellar cortical vein emptying into the tentorial sinus was identified in 83.3% of the patients; it was delineated on 54 sides with an average number per right hemisphere of 1.9 and 63 sides with an average number per left hemisphere of 2. The pontine-trigeminal and anterior hemispheric veins emptying into the superior petrosal sinus were identified in 42.2% of the patients. Conclusions The BVs of the cerebellum can be classified into six distinct routes. Radiological classification may be useful for understanding the drainage pattern of the cerebellum.