Venous Angiomas of the Brain A

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systems," Venous angiomas may be Venous angiomas of quite small, draining a limited region of the brain, or may be very large, the brain a sometimes draining an entire hemi- • sphere. They can be single or multiple, and even bilateral.P" The com- review monest sites of occurrence are in the frontal and parietal lobes of the cere- venous anomaly' or DVA, pointing bral hemispheres and in the cerebel- Ian C Duncan out that these abnormalities actual- Ium.':" They can also be found in the ly represented an extreme anatomi- FFRad(D)SA occipital and temporal lobes, basal cal variant of the normal venous ganglia and pons." Unitas Interventional Unit POBox 14031 drainage of the brain. Lytlelton Imaging 0140 Pathology The classical radiographic appear- The theory of the development of ance of these abnormalities accurately venous angiomas is that there is fail- reflects the anatomical picture with Introduction ure of regression of normal embryon- multiple enlarged transmedullary Venous angiomas of the brain, also ic transmedullary venous channels. veins radiating in a wedge or radial termed venous malformations or These persistent transmedullary veins pattern toward the larger collecting developmental venous anomalies run axially through the white matter vein producing the pathognomic (DVA) are commonest of the to drain into a single larger calibre col- 'caput medusae' or 'spoke wheel' intracranial vascular malformations lecting venous trunk. The dilated ter- appearance during the venous phase comprising between 50% and 63% of minal collecting vein then penetrates of a cerebral angiogram (Figs 1,2).14,15 all intracranial vascular malforma- the cortex to drain either superficially A similar appearance is often seen on tions. They may be found in as many into cortical veins or dural sinuses, or computed tomographic (CT) or mag- as 2 - 2.5% of the general population." deeply in the subependymal veins and netic resonance (MR) scanning of the The term 'venous angioma' was deep venous system. In the posterior brain (Fig. I), although with smaller introduced by Russel and Rubin- fossa collecting veins may drain into angiomas often only the collecting stein in 1951.4 In 1963 Courville' the ponto mesencephalic or cerebellar vein is seen (Fig. 3). These angiomas first suggested the concept that veins. A further effect of this apparent are best seen on CT scanning follow- venous angiomas represent com- halt in venous anatomical develop- ing contrast administration. Similarly, pensatory venous drainage path- ment is that there is regional hypopla- they are also usually best seen on MR ways in the brain. Later reports sia or aplasia of norma! pial veins in imaging on contrast-enhanced Tl- indicated that these venous the same area of the brain. The result weighted images.":" The collecting angiomas seemed to drain normal of this is that the anomalous vein veins are seen as either straight or ser- brain tissue and were to be consid- drains the normal brain tissue in the piginous enhancing structures tra- ered as anomalous venous drainage area affected. versing the brain parenchyma on CT systems." Huang et al? described In the cerebral hemispheres, or MR. They may be seen as flow these anomalies as being purely Valavanis et aP described both super- voids on standard unenhanced Tl venous with no associated arterial ficial and deep types. With the super- and proton density MR sequences or capillary abnormalities and sug- ficial type there is drainage of the (Fig. 2), and due to slow flow the col- gested the term 'medullary venous subependymal and deeper medullary lecting veins may also show as hyper- malformation' rather than venous regions into the cortical veins, and intense on T2-weighted images. The angioma. with the deep type the blood from the enhancement of the collecting veins Finally in 1986 Lasjuanias et al.8 subcortical white matter drains into with gadolinium on MR scanning in coined the term 'developmental the subependymal and deep venous keeping with other normal venous

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structures of the brain is in contrast to the appearance of dilated veins in a high-flow situation such as is seen with the veins draining an arteriovenous malformation or fistula, where these veins tend to show as flow voids on all sequences despite contrast administration. Occasionally decreased signal intensity may be seen in venous angiomas on gradient-echo MR images due to magnetic susceptibility resulting from deoxyhaemoglobin in

Fig. 1. Cerebellar venous angioma: characteristic appearance. Axial contrast-enhanced T1-weighted MR the veins." Venous angiomas can be image (Fig. 1a) with corresponding venous retum phase Image during a selective left vert9bral arteriogram (Fig. 1b) both showing tne typical 'caput medusae' appearance of a venous angioma within the cerebellum. seen on MR venography but this sel- dom adds any more information than standard multiplanar MR imaging. During angiography these venous angiomas are seen during the venous return phase of a selective cerebral angiogram. The arterial phase is generally normal although occasional regional arterial supply variations may be seen. A prominent late capillary blush may be seen in the area drained by a venous angioma followed by fill- ing of the medullary veins and later the collecting vein producing the characteristic angiographic appearance. Patholo~ical associations Although most venous angiomas occur in isolation, usually found as incidental findings, they are known to have associations with other cranial vascular and developmental abnormalities. These include cavernous malformations, arteriovenous malformations, capillary telangiectasias, sinus pericranii and other facial vascular malformations, and cortical dysplasias and other migrational brain Fig. 2. Frontal venous angioma: characteristic appearance. Contrest-enhanced axial CT (Fig. 2a) and axial abnormalities. Venous angiomas may proton-density MR (Fig. 2b) images at the same level showing a venous angioma in the left frontal lobe. It shbws as an enhancing stll./Ctureon the tenner and as a How-voidon the latter. The venous retum phase be associated with other intracranial images of a selective left intemal carotid arteriogram (Figs za. 2d) show the same deep venous angioma draining superficially. vascular malformations in up to 9% of cases.

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The association of venous angiomas with cavernous malformations suggests a common malformative mechanism, possibly with the presence of the cavernous malformation somehow triggering the development of the venous anomaly (Fig. 4). Lasjaunias" has disputed this, postulating that the haemodynamic differences created by the anomalous venous drainage may, in fact, trigger the formation of the cavernoma at a later stage. Occasionally a true arteriovenous malformation may drain into the collecting vein of a venous Fig. 3 . Probable brainstem venous angioma. Axial T2-weighted (Fig. 38) and contrast-enhanced T1-weight- angioma. In a very small percentage ed (Fig. 3b) images showing a linear vascular structure traversing the brainstem on the right at the level of the pons In a patient who presented with an ipsilateral trigeminal neuralgia. The linear structure is probably (< 5%) of venous angiomas, associat- the col/ecting trunk of a brainstem venous angioma. This was not confirmed angiographical/y. Its relationship to the clinical presentation is questionable. ed tiny arteriovenous fistulas can be identified at angiography where small, slightly dilated arteries are seen to drain directly into the medullary veins. Mullan et al" have postulated that cerebral venous malformations and arteriovenous malformations share a related malformative mechanism, and the presence of these microfistulas seen with some venous angiomas seems to lend credence to this theory. Venous angiomas may also occasionally be associated with intracranial varix with stenotic nar- rowing of the outlet of the collecting vein leading to ectasia of the collect- Fig. 4. Venous angioma with associated cav- ing vein," emous angioma. A contrast-enhanced axial T1- weighted image shows the characteristic 'caput Two groups of anomalies also medusae' appearance of a periventricular venous angioma in the left frontal lobe (Fig. 4a). A coronal found in association with venous T1 image shows the same venous angioma with angiomas in children include cranio- an associated cavemous angioma barely visible above it (Fig. 4b). A coronal FLAIR image shows facial vascular malformations and the more typical MR appearance of the associated cavemous angioma (Fig. 40). cortical dysplasias. The craniofacial vascular anomalies that have been described in association with venous angiomas include facial port-wine stains, lymphatic malformations, venous malformations, frontal varices, prominent transcranial veins and sinus pericranii.?" The association with port-wine stains and lym-

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phatic malformations appears to be coincidental as no direct causative link has yet been established. An equally rare situation is the presence of a large hemispheric venous angioma draining transcraniallythrough a sinus pericranii defect," A sinus pericranii defect is an osteodural venous anomaly where the intracranial venous drainage joins a midline sinus before draining externally through a skull defect directly into subcutaneous veins. The association of venous angioma with cortical migration and sulcation defects such as cortical dysplasia, pachygyria, polymicrogyria or schizenephaly suggests a link between arrested neuronal migration and failed transmedullary venous regression during early embryonic life (Fig. 5).22 Yet another rare association is with the blue rubber bleb nevus syndrome where multiple venous angiomas are associated with cuta- neous naevi." Clinical features The clinical behaviour of venous Fig. 5. Persistent transmedul/ary veins associated with arrested neuronal migration. Unenhanced (Fig. 58) and contrast-enhanced (Fig. 5b) sagittal T1, T2 (Fig. Sc), and contrast-enhanced T1-weighted axial (Fig. 5d) angiomas remains somewhat contro- images of a patient with right frontal lobe cortical dysplasia showing radially orientated vascular structures traversing the dysplastic parenchyma (white matter). This is in keeping with persistence of embryonal medullary versial. Venous angiomas have been veins related to the arrested neuronal migration. associated with a number of clinical presentations including headache, haemorrhage, epilepsy and progres- occurring in the posterior fossa.":" Because of these associations it is felt sive neurological deficits. In many Higher rates of haemorrhage were that many of the haemorrhages relat- cases their presence is probably coin- undoubtably reported in the days ed to venous angiomas probably arise cidental but in some cases may be prior to the use of cross-sectional and from other undetected associated causative. Headache is the common- in particular MR imaging. The wide- occult vascular malformations and est symptom associated with venous spread use of MR imaging has shown not the venous angiomas them- angiomas, found in up to 43% of that the majority of venous angiomas selves.":" cases." detected are found as incidental There are a number of reports Their association with haemor- lesions.":" MR imaging has also describing haemorrhage directly rhage has also been somewhat contro- shown the association of venous attributable to a venous angioma itself versial with reported haemorrhage angiomas with other angiographically resulting from spontaneous thrombo- m4 rates of between 0% and 43%.'7.24 occult cerebrovascular malformations sis of the collecting vein. Very rarely Historically venous angiomas have including cavernous malformations they may present with subarachnoid been known to be associated with and capillary telangiectasias, particu- haemorrhage.' haemorrhage, particularly those larly within the posterior fossa.":" Spontaneous thrombosis of the

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collecting vein can result in venous venous angioma itself. Occasional direct treatment of these lesions is infarction of the area drained by a spontaneous thrombosis of these contraindicated and should rather be venous angioma."> lesions has been described leading to directed at any other relevant associat- A small number (0.4%) of patients venous infarction of the brain in keep- ed amenable pathology. presenting with epilepsy are shown to ing with the fact that these venous have venous angiomas. Although angiomas are anatomical variants References some of the these are almost certainly which drain normal brain tissue. For 1. Garner TB. Curling OD. Kelly DI. Laster DW. The natural history of intracranial venous incidental findings, the possible asso- this reason attempted resection of a angiomas. J Neurosurg 1991;75: 715-722, ciated presence of cortical dysplasia or venous angioma generally has a cata- 2, Ostertun B. Solymosi L. Magnetic resonance strophic outcome." Similarly, radio- angiography of cerebral developmental venous the vascular malformation may have a anomalies: Its role in differential diagnosis, more direct aetiological relationship surgery is contraindicated for the Neuroradiology 1993;35: 97-104. with seizure activity?" management of venous angiomas." If 3. Truwit CL. Venous angioma of the brain: History. significance and imaging findings. AfR Other clinical features that have indicated, any direct surgical or other 1992; 159: 1299-1307. been ascribed to the presence of a treatment should rather be aimed at 4. Russel DS. Rubinstein LJ.Pathology of Tumours of the Nervous System, London: Edward Arnold. venous angioma include motor relevant associated pathologies such 1951:78-79, deficits and sensory disturbances," as cavernous malformations or capil- 5. Courville CB. Morphology of small vascular malformations of the brain. J Neutopathol Exp trigeminal neuralgia.?" hemifacial lary telangiectasias which have a clear Neuro11963; 22: 274-284, spasm" and hydrocephalus." These risk of haemorrhage, or cortical dys- 6. Senegor M. Dohrmann GJ. Wolmann RL. Venous angiomas of the posterior fossa should symptoms are thought to be due to plasias in intractable epilepsy. be considered as anomalous venous drainage. direct pressure effectsof the associated Surg Neuro11983; 19: 26-32. Conclusion 7, Huang YP, Robbins A. Patel se. Cerebral venous angioma. venous malformations. In: Kapp JP, Schmidek HH. eds. The Cerebral Venous System and its Venous angiomas are extreme Disorders. New York:Grune and Stratton. 1984: Differential variants of normal brain venous 373-474, diagnosis 8. Lasjaunias P, Burrows P, Planet e. Develop- anatomy, representing failure of mental venous anomalies (DVA):the so-called In many casesthe imaging appear- regression of normal early embry- venous angioma, Neurosurg Rev 1986; 9: 233- 242. ological venous drainage pathways. ance of venous angiomas is relatively 9. ValavanisA. Wellauer J, YasargilMG. The radi- straightforward and pathognomic, They are generally benign lesions, ological diagnosis of cerebral venous angioma: cerebral angiography and computed tomogra- regardless of the modality used. often found coincidentally on CT or phy. Neuroradiology 1983;24: 193-199. Dilated veins may be seen related to MR scans or at angiography. They 10. Uchino A. Sawada A.Takase Y, Abe M. Kudo S, Cerebral hemiatrophy caused by multiple an arteriovenous malformation or can be seen in association with other developmental venous anomalies involving intracranial or craniofacial vascular nearly the entire cerebral hemisphere, Clin highly vascular tumour but the associ- Imaging2oo1; 25: 82-85, ated lesion is usually apparent on sec- abnormalities or cerebral dysplasias. 11. Uchino A. Hasuo K, Matsumoto S. Masuda K. Their appearance on imaging is gen- Double cerebral venous angiomas: MRT, tional imaging. Dilated medullary Neuroradiology 1995;37: 25-28. veins may be seen in some cases of erally pathognomic regardless of the 12, Lee C. Pennington MA. Kenney CM, MR eval- modality used. Confirmation of a uation of developmental venous anomalies: dural arteriovenous fistula with corti- medullary venous anatomy of venous cal venous reflux," Visible persistent venous angioma by angiography is angiomas. Am JNeuroradiol1996; 17: 61-70. medullary veins may be seen in the generally not required, although MR 13. Herrero A. Martinez-San Millan J. Martinez- Castillo JC. Ginestal R. Alvarez-Cerrneno Je. area of a cortical dysplasia or other scanning is probably required in most Developmental venous anomaly of the pons, migrational disorder," cases to exclude an associated angio- Neurology 2001; 57: 744. 14. Rigamonti D. Spetzier RF, Medina M. graphically occult vascular malforma- Rigamonti K. Geckle DS. Pappas e. Cerebral Treatment tion or focal cortical dysplasia. The venous malformations. J Neurosutg 1990; 73: 560-564. The general consensus is that by risk of haemorrhage is generally that 15. Saba PR. The Caput Medusae sign. Radiology themselves venous angiomas are very of any associated occult vascular mal- 1998;207:599-600. 16. Wilms G, Demaerel P, Marchal G. Baert AL. benign lesions. The risk of haemor- formation. Venous angiomas may be Plets e. Gadolinium-enhanced MR imaging of associated with other neurological cerebral venous angiomas with emphasis on rhage is generally that of any associat- their drainage.] Comput Assist Tomogr 1991;15: ed cavernous or capillary malforma- abnormalities but are very rarely the 199-206. tion rather than any risk from the direct cause thereof. Surgical or other 17. Hallam DK, RusselEJ.Imaging of angiographi-

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cally occult cerebral vascular malformations. Neuroimaging Clin NAm 1998; 8: 323-347. 18. Lasjaunias P. Venous anomalies and malformations. In: Lasjaunias P, Ter Brugge K, eds. Vascular Disease in Neonates, Infants and Children. Berlin: Springer, 1997: 445-471. 19. Mullan S, Mojtahedi S, Johnson DL, MacDonald RL. Cerebral venous malformation - arteriovenous malformation transition forms. J Neurosurg 1996; 85: 9-13. 20. Uchino A, Hasuo K, Matsumoto S,Ikezaki K. Masuda K.Varix occurring with cerebral venous angioma: a case report and review of the literature. Neuroradiology 1995; 37: 29-31. 21. Boukobza M, Enjolras 0, Guichard JP' et al. Cerebral developmental venous anomalies associated with head and neck venous malformations. Am J Neuroradiol1996; 17: 987-994. 22. Barkovich AJ.Abnormal vascular drainage in anomalies of neuronal migration. Am J Nellroradiol1988; 9: 939-942. 23. Sherry RG, White ML, Olds MV: Sinus pericranii and venous angioma with the blue-rubber bleb nevus syndrome. Am J Neuroradiol1984; 5: 832-834. 24. Biller J,Toffel GJ, Shea JF,Fine M, Azar-Kia B. Cerebellar venous angiomas: a continuing controversy. Arch Neuro11985; 42: 367-370. 25. Rothfus WE, Albright AL, Casey FK, Latchaw RE, Roppolo HM. Cerebellar venous angioma: 'Benign' entity? Am J Neuroradiol1984; 5: 61-66. 26. Malik GM, Morgan JK, Boulos RS,Ausman JLVenous angiomas: An under- estimated cause of intracranial haemorrhage. Surg Neuro11988; 30: 350-358. 27. Chaloupka JC, Huddle DC. Classification of vascular malformations of the central nervous system. Neuroimaging Clin NAm 1998; 8: 295-321. 28. Wilms G, Demaerel P, Robberecht W. Coincidence of developmental venous anomalies and other brain lesions: a clinical study. Eur Radio11995; 5: 495- 500. 29. Abe T, Singer RJ, Maries Mp, Norbash AM, Crowley RS, Steinberg GK. Coexistence of occult vascular malformations and developmental venous anomalies in the central nervous system: MR evaluation. Am J Neuroradiol 1998; 19: 51-57. 30. Wilms G, Bleus E, Demarerel P, et al: Simultaneous occurrence of developmental venous anomalies and cavernous angiomas. Am J Neuroradiol1994; 15: 1247-1254. 31. McCormick PW, Spetzler RF, Johnson PC, Drayer BP. Cerebellar haemorrhage associated with capillary telangiectasia and venous angioma: A case report. Surg Neuro11993; 39: 451-457. 32. Mclaughlin MR, Kondziolka D, Flickinger JC, Lunsford LD, Lunsford LD. The prospective natural history of cerebral venous malformations, Neurosurgery 1998; 43: 195-200. 33. Field LR, Russel EJ. Spontaneous haemorrhage from a cerebral venous malformation related to thrombosis of the central draining vein: Demonstration with angiography and serial MR. Am J Neuroradiol 1995; 16: 1885-1888. 34. Yamamoto M, lnagawa T, Kamiya K, Ogasawara H, Monden S, Yano T. Intracerebral haemorrhage due to venous thrombosis in venous angioma - case report. Neurol Med Chir 1989; 29: 1044- I046. 35. Lai PH, Chen pc, Pan HB,YangCF.Venous infarction from a venous angioma occurring after thrombosis of a drainage vein. Am J Roentgenol 1999; 172: 1698-1699. 36. Konan AV,Raymond L, Bourgouin P, Lessage J, Milot G, Roy D. Cerebellar infarct caused by spontaneous thrombosis of a developmental venous anomaly of the posterior fossa. Am J Neuroradiol1999; 20: 256-258. 37. Awad lA, Robinson JR, Mohanty S, Estes ML. Mixed vascular malformations of the brain: Clinical and pathological considerations. Neurosurgery 1993; 33: 179-188. 38. Striano S, Nocerino C, Striano P, et al. Venous angiomas and epilepsy. Neurolgocial Sciences 2000; 21: 151-155. 39. Nagata K, Nikaido Y, Yuasa T, Fujioka M, Ida Y, Fujimoto K. Ttigerninal neuralgia associated with venous angioma - a case report. Neurol Med Chir 1995; 35: 310-313. 40. Chen HJ, Lee TC, Lui Cc. Hemifacial spasm caused by a venous angioma: a case report. ] Neurosurg 1996; 85: 716-717. 41. Blackmore CC, Mamourian AC. Aqueduct compression from venous angioma: MR findings. Am J Neuroradiol1976; 17: 458-460. 42. Lindquist C, Guo WY, Karlson B, Steiner L. Radiosurgery for venous angiomas. J Neurosurg 1993; 78: 531-536.

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