Depiction of the Superior Petrosal Vein Complex by 3D Contrast-Enhanced MR Angiography

Transversal MIP at the level of the drainage of the SPV into the SPS (type II, internal acoustic meatus not shown). The tributary veins are clearly identifiable: lateral mesencephalic vein (asterisk, posterior mesencephalic group, anastomosis to the basal vein), transverse pontine vein (anterior pontomesencephalic group), and vein of cerebellopontine fissure (petrosal group). The artificial union of the SCA and the transverse pontine vein is clearly distinguishable on the original imaging data (asterisk, depending on the literature, also named pontotrigeminal vein and brachial tributary of the superior petrosal vein). BA indicates basilar artery; SCA, superior cerebellar artery; VCPF, vein of cerebellopontine fissure; infr. tent. segm. of anast, infratentorial segment of anastomosing.

Scatterplot of the diameter of the SPV versus the combined diameters of its anastomoses. To better visualize overlaying data points, we added a random offset between −0.025 and 0.025 to each diameter. SPVs with no visible anastomosis are shown as red circles, while x represents SPVs with at least 1 anastomosis (green indicates the diameter of the SPV ≤ 2 mm; blue, diameter of the SPV of > 2 mm). SPVs with a diameter of >2 mm are considered dangerous by Zhong et al.⁶

A, Intraoperative view shows that the venous anatomy is hidden for the neurosurgeon by the meningioma (white dots). B, After removal of the tumor, the neurosurgeon can see the medial superior petrosal vein (type III) and the trigeminal nerve (arrow). Two tributaries are encountered in concordance with the MR imaging. A schematic drawing (C) based on axial MIP reconstruction (D) of the preoperative 3D-MRA shows a compressed single SPV (asterisk in C) just ventral to the meningioma, with 2 tributaries and a main drainage via a pontine transverse vein and the anterior pontomesencephalic vein. Although the location was known, partial thermocoagulation (note the different color of the SPV marked with an asterisk in B) of the previously compressed SPV could not be prevented. The dorsal region of the cerebellum had direct drainage into the basal vein via a large lateral mesencephalic vein (not shown). V indicates vein; V. of Cer. Pon. Fiss, vein of the cerebellopontine fissure; Bas. Art., basal artery; Ant. Pon. Mes. V, anterior pontomesencephalic vein; Sup. Petr. Sinus, superior petrosal sinus; Trans. Pon. V., transverse pontine vein; Tent. Vein, tentorial vein; Trans. Sin, transverse sinus.