MR high-resolution blood oxygenation level-dependent venography of occult (low-flow) vascular lesions.

developmental venous anomalies can be subtle on many MRI sequences T1 C+ and SWI are most sensitive.

think of an associated cavernoma when a developmental venous anomaly is found in the context of an intraparenchymal hemorrhage investigation, as isolated DVAs rarely bleed.demyelination may also have enlarged medullary veins.Sturge-Weber syndrome with leptomeningeal angiomatosis.dural sinus thrombosis or dural arteriovenous fistula with collateral transparenchymal drainage.In some instances, imaging appearances may be atypical or be confounded by concurrent pathology (e.g. Generally, the appearances will be typical and no differential should be offered. The importance of the preserved integrity of the DVA itself still holds true 6. The authors suggested identification of the underlying pathomechanism by MR and DSA for proper management. When isolated, developmental venous anomalies have a very low complication rate (0.15% per annum) mainly from spontaneous thrombosis of the collecting vein leading to venous infarction and hemorrhage.Ī more recent study has demonstrated that in exceedingly rare cases, the DVA can become symptomatic by various vascular complications. Informing the surgeon of the presence of a DVA is, however, essential as cautery of the collecting vein can lead to venous infarction of the brain parenchyma it drains. If part of a mixed vascular malformation then treatment will be predicated on the other component.

If isolated developmental venous anomalies require no treatment. It will, however, be the same as other veins and the opposite of calcification. The signal intensity of veins will be low on SWI images but will vary on phase imaging depending on the vendor. Therefore, SWI has successfully demonstrated low-flow vascular formations such as DVA. SWI is the preferred sequence in venous anomalies and proved to have better detectability of venous structures than conventional T2*-weighted imaging. Signals on SWI are not compromised by low-velocity venous flow. If there is an associated cavernous hemangioma, then susceptibility weighted sequences will be most sensitive to this component.Īdditionally, in ~10% of cases, high T2/FLAIR signal can be seen in the surrounding white matter the etiology is not clear but may be due to gliosis, edema or leukoaraiosis 12. MRIĭevelopmental venous anomalies are often visible on most sequences but can be subtle and are most easily seen on postcontrast T1 sequences and susceptibility weighted imaging (SWI). Arterial phase appears normal although late capillary blush may be present. Angiography (DSA)Īngiographically the caput medusae appearance (collection of dilated medullary veins converge in an enlarged transcortical or subependymal collector vein) is pathognomonic and seen only in the venous phase. This can be particularly prominent in the basal ganglia and thalami resulting in unilateral calcification 10,11. If large, the draining vein may be seen on non-contrast CT and is confirmed with contrast administration as a linear or curvilinear enhancing structure.ĭystrophic calcifications may be seen associated in up to 9.6% of the cases 9. venous malformations of the head and neck 2ĭevelopmental venous anomalies are seen on both CT and MRI as a leash of vessels draining towards a central vein.~20% (range 8-33%) of cases 2 are associated with cavernous malformations and are referred to as mixed vascular malformations (MVM).lesions are usually solitary (75%) 2, except in blue rubber bleb nevus syndrome.However, DVAs can be seen anywhere, draining either superficially or deep. cerebellar hemisphere (14-27%) draining towards the fourth ventricle.frontoparietal region (36-64%) 1, usually draining towards the frontal horn of the lateral ventricle.Histologically they consist of a number of abnormally thickened veins with normal feeding arteries and capillaries 3. The etiology of developmental venous anomalies remains uncertain but may relate to arrested development of venous structures 2,3. An association has also been described with ischemic stroke and epilepsy 8. However, patients can present with intracranial hemorrhage (1-5%). Clinical presentationĭevelopmental venous anomalies are usually incidental findings. DVAs are very common as incidental finding, with an estimated prevalence of 2.5-9% on contrast-enhanced MRI scans 13.

Developmental venous anomaly