Developmental Venous Anomaly: MR and Angiographic Features
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JBR–BTR, 2014, 97: 17-20. DEVELOPMENTAL VENOUS ANOMALY: MR AND ANGIOGRAPHIC FEATURES M. Faure1, M. Voormolen1, T. Van der Zijden1, P.M. Parizel1 Developmental venous anomaly (DVA) is probably the most common anomaly of the intracranial vasculature. DVAs consist of multiple, radially oriented dilated medullary veins that converge into a transcerebral vein. We describe the imaging findings of this vascular anomaly in different patients and the role of different imaging modalities. Key-words: Cerebral blood vessels, abnormalities – Cerebral blood vessels, MR – Cerebral angiography. Developmental venous anomaly (DVA) was first considered a rare vascular malformation (1, 2). Nowa- days, with the advent of Computed Tomography (CT) and especially Magnetic Resonance Imaging (MRI), DVAs are seen every week to month by radiologists (3, 4). Most DVAs are solitary, asymptomatic lesions and are discovered incidentally. They have a relatively benign nature with a low incidence of hemorrhage. When they do bleed, this is thought to be due to associated vascular mal- formations, like cavernous angiomas. The typical angiographic appearance of a DVA is a caput medusae appear- ance in the venous phase. MRI com- bined with MR angiography (MRA) replaces angiography in most un- A B complicated cases as a non-invasive alternative (3, 5). Case reports Case 1 A 32-year-old woman presented with headache, with no particular location and no neurological deficit. MRI of the brain was made in another hospital that showed a flow void running transcerebral, suggestive for a vascular malformation (Fig. 1A,B). Initially, there was no gadolinium contrast given and an arterial feeder could thus not be excluded with MRI. C D Patient was referred to our hospital to perform a cerebral angiography to Fig. 1. — Axial T2-weighted MR-images showing a focus of abnormal signal in the left parietal lobe (A) with a flow void running transcerebral, suggestive for a vascular further characterize the vascular malformation (B). Anteroposterior (C) and lateral (D) cerebral angiography, venous malformation and to exclude an arte- phase, show the typical appearance of a DVA in the left parietal lobe with the caput riovenous malformation (AVM). The medusae of dilated medullary veins (arrows), accompanied by a single, large draining angiography gives the definitive di- vein that drains in the superior sagittal sinus (arrowhead). agnosis of a DVA in the left parietal lobe by showing typical dilated medullary veins – caput medusae Case 2 hypointense rim in the left frontal white matter and is in close relation- appearance –, without arterial feed- A 53-year-old man presented with ship with the frontal horn of the left ers, that drain into a transcerebral acute headache in another hospital. lateral ventricle. This lesion repre- vein. This vein drains into the supe- MRI of the brain showed a lesion sents a cavernous malformation. rior sagittal sinus (Fig. 1C, D). with heterogeneous signal intensity, There are some additional vascular structures adjacent to the cavernoma. Cerebral angiography was performed From: 1. Department of Radiology, UZ Antwerpen, Antwerp, Belgium. to further characterize these struc- Address for correspondence: Dr. M. Faure, Department of Radiology, UZ Antwerpen, tures and to exclude an AVM. The Wilrijkstraat 10, 2650 Edegem, Belgium. E-mail: [email protected] angiography showed the presence faure-.indd 17 24/02/14 10:08 18 JBR–BTR, 2014, 97 (1) A B C E F Fig. 2. — Axial T2-weighted MR-images through the brain (A) show a lesion with D heterogeneous signal and hypointense rim in the left frontal white matter, in close re- lationship with the frontal horn of the left lateral ventricle, representing a cavernous malformation. Axial T1-weighted images post gadolinium obtained at the same level (B, C) reveal contrast-enhancing vascular structures adjacent to the cavernoma, representing an associated DVA. Susceptibility- weighted imaging (SWI) (D) shows striking hypointense ‘blooming’ of the cavernous malformation. Cerebral angiography, venous phase, sagittal views (E, F) confirm the presence of a DVA in the right frontal white matter (arrows), draining into the thalamostriate vein (arrowhead), in turn draining to the great cerebral vein. of a DVA in the right frontal white DVAs consist of multiple, radially drainage of the white matter rather matter, draining into the thalamostri- oriented dilated medullary veins that than a true vascular malformation (3, ate vein, in turn draining to the great drain normal cerebral nervous tissue 4, 7). The etiology is unclear. DVAs cerebral vein (Fig. 2). and are located in the white matter. are mostly found in the frontal and These medullar veins converge into cerebellar white matter, respectively Discussion a trancortical or subependymal in 50 and 25% of cases (3, 8) draining vein. This vein drains into a DVAs are thought to be benign en- DVA is probably the most com- superficial cortical vein or dural sinus tities that are unlikely to become mon anomaly of the intracranial vas- or to a deep ependymal vein. The symptomatic, although headache culature. Usually, they are discov- enlarged veins provide the main and epilepsy are reported. Most ered as incidental lesion on imaging venous drainage for intervening DVAs are discovered incidentally at studies. DVA is about 3 to 4 times normal brain. contrast-enhanced CT or MRI (9, 10). more prevalent than AVM. They rep- DVAs were previously known as There is controversy about the hem- resent 60% of the cranial vascular venous angiomas, venous malfor- orrhagic risk of a DVA. It remains un- malformations found at autopsy and mations or medullary venous mal- clear whether the hemorrhage is al- occur in up to 4% of the popula- formations. This terminology is re- ways caused by an associated occult tion (3, 6). Most DVAs are asymp- placed by DVA because it represents cavernous malformation, or that it tomatic and solitary lesions. an anatomical variant of venous may be caused by the DVA itself. faure-.indd 18 24/02/14 10:08 DEVELOPMENTAL VENOUS ANOMALY — FAURE et al 19 hemorrhagic events. However, small AVMs or micro AVMs cannot be shown by MRI/MRA. In some cases there is variable enhancement of the brain parenchyma at enhanced MRI. It is suggested that this enhance- ment indicates venous restrictive disease in association of the draining vein and thus possibly also associat- ed with a higher risk of bleeding (4, 14). Susceptibility-weighted imaging (SWI) can also be used to image venous structures. SWI appears to have a better detectability of venous structures than conventional T2*- weighted imaging (15). Therefore, SWI can be useful to detect DVA. They typically have a low signal in- tensity on SWI due to the blood oxy- gen level-dependent (BOLD) effect in A B the dilated medullary and draining Fig. 3. — Susceptibility-weighted imaging (SWI) is very sensitive to venous blood veins (Fig. 3). and show the DVA as a hypo-intense lesion. Conclusion Developmental vascular anomaly Possibly thrombosis or stenosis of ficial cortical vein or dural sinus. The (DVA, formerly known as venous an- the draining vein can cause a hemor- arterial phase of the cerebral angio- gioma, venous malformation or rhagic event (9, 11, 12). gram is normal in most cases. Angio- medullary venous malformation) is There is a coexistence between graphy is still the best technique to probably the most common anoma- DVAs and vascular malformations, image DVA and to differentiate it ly of the intracranial vasculature and especially cavernous malformations. from AVMs which have a different represents an anatomical variant of Abe et al found a coexistence of 33% clinical significance. Cavernous mal- venous drainage rather than a true between DVA and cavernous malfor- formations and capillary telangiecta- malformation. They have a relatively mations with a relative high preva- sias are angiographically occult. benign nature with low incidence of lence of coexisting lesions in the Unenhanced imaging studies are hemorrhage. When bleeding is posterior fossa (5). Although less normal in approximately 50%. On found, this is thought to be due to an commonly reported, DVAs may be unenhanced MR images DVAs typi- associated vascular malformation, associated with neuronal migration cally show a transhemispheric flow like a cavernous angioma. Alterna- anomalies, such as cortical dyspla- void on the T1- and T2-weighted im- tively, thrombosis or stenosis of the sias (4). Multiple DVAs can be found ages with normal non-gliotic sur- draining vein of a DVA is thought to in the blue rubber bleb nevus syn- rounding parenchyma. Enhanced CT give a hemorrhagic event. DVAs are drome or in sinus pericranii. and MRI have a sensitivity of over often seen incidentally at CT or MRI. In contrast to other vascular mal- 85% for detection of DVAs. Enhanced Although angiography still is the formations in the brain, DVA resec- CT and MRI can show the draining best technique to image DVA, with tion is not recommended. Because vein of the DVA as a linear area of the typical caput medusae appear- they drain normal brain tissue, re- enhancement, that courses from the ance in the venous phase, invasive section of these venous pathways is deep white matter to a superficial or imaging is nowadays mostly re- associated with high morbidity and deep vein or to a dural sinus. 2D MRI served for complicated cases and in mortality and major neurologic com- (time-of-flight) angiography can case of acute hemorrhage to differ- plications (7, 12). show the pathognomic features of a entiate it from AVM. MR angiogra- DVA in more than 85% of cases (10, phy can be an adequate non-invasive 13). 2D-MRA is superior to 3D meth- alternative to diagnose a DVA. Imaging ods for the imaging of slow flow ves- DVAs were thought to be rare be- sels, like veins, because they have References fore the advent of CT and MRI imag- less saturation effects.