NOVEMBER, 1974 ROENTGENOGRAPHIC ANALYSIS OF ARTERIOVENOUS MALFORMATIONS OF THE OCCIPITAL LOBE* By B. TODD TROOST, M.D.,t and THOMAS H. NEWTON, M.D4 T HE blood supply of cerebral arteriovenous malformations is often extensive and depends on the cranial or intracranial location as well as the size of the lesion.8 No previously reported study has analyzed the roentgenologic and clinical features of malformations which primarily involve the occipital lobe. This report discusses the roentgenographic anatomy and summarizes the clinical leatures in 25 patients with arteriovenous malformation of the occipital lobe. MATERIAL A review of the angiographic files at the University of California Medical Center, San Francisco, produced 25 examples of arteriovenous malformations of the occipital lobe. The majority of the patients had been clinically evaluated by the staff of the Neuro-Ophthalmology Unit. The angiograms and clinical records were analyzed to determine if any anatomic findings could be correlated with the clinical problems caused by these lesions. The patients in the study ranged in age from 15 to 6o years with an average age of 37 years. Ten patients were women and 15 men. Follow-up periods varied from a few weeks to io years. Two patients died from complications after surgical procedures, and i patient died from an intracerebral hemorrhage 8 years after the diagnosis was established. RESULTS The clinical features of these cases are presented in a separate report. Thirteen patients experienced visual phenomena such as flashes of light and dimming of SAN FRANCISCO, CALIFORNIA vision : Seven had nonmigrainous, transient, cortical photopsias or scotomas and 7* described partial loss of vision. Nine patients had epilepsy and 6 of these 9 patients experienced visual aurae. Headaches were particularly common and were both acute and chronic. The headaches were predominantly unilateral and frontaloccurring on the side of the occipital lesion in all but patient. Severe, explosive headaches signified intracranial bleeding. Nine patients had severe headache followed shortly by complete homonymous hemianopsia-the syndrome of occipital apoplexy. The most common neurologic abnormality of the initial examination was homonymous hemianopsia, present in i patients. The nonvisual signs included paralysis of the third nerve in 2 patients (the result of an accompanying aneurysm), hemiparesis in 5 patients, and a vascular bruit in patients. Roentgenographic diagnosis depended mainly on angiographic studies. The occipital lesions were right-sided in II instances and left-sided in 14. The angioma was confined to the occipital lobe in 13 patients, the occipitoparietal area in 9 patients, and the occipitotemporal region in 3 patients. The size of the malformation was classified according to the largest dimension into 3 grades: small (i cm. or less), 7 patients; medium (2 to 4 cm.), 12 patients; and large (5 cm. or more), 6 patients. The roentgenographic features are listed in Table i. On plain roentgenograms, abnormalities of the skull were noted in only 3 patients. These abnormalities consisted of an enlarge- * One patient had both phenomena. * From the Neuro-Ophthalmology Unit,t Department of Neurological Surgery, and the Department of Radiology (Professor, Neuroradiology), University of California Medical Center, San Francisco, California. t NIH Fellow in Neuro-Ophthalmology (Fellowship No. I Fi i EY 3-01). 538
VOL. 122, No. 3 Arteriovenous Malformations of the Lobe 539 TABLE ROENTGENOGRAPHIC FEATURES OF OCCIPITAL LESIONS IN 25 PATIENTS* I iase 0. I 2 3 4 Location Size (cm.) Occipitotemporal 2X2X2 ax ix i 5X4X 5X3X4 S Hematoma Arterial Supply MCA PCA ECA PERIC Venous Drainage Dural, torcula Torcula, transverse S 3X 3X 4 Torcula, superior sagittal Occipitotemporal 6 7 8 10 9 I I Occipitoparietal Occipitopanietal 4X 3X 3 2X3X2 7X6X 7X4X4 I.sX IX I 4X 44 Vein ofgalen, superior 12 Occipitoparietal 3X3X2?t Superior, lateral, and 13 4 5 i6 7 18 Occipitopanietal Occipitoparietal Occipitoparietal Occipitopanietal IXIXi 3XSXI 3X4X2 ix ix I 3X4X2 3X3X3?t sagittal Torcula, superior sagittal straight Torcula es Vein of Galen, supenor sagittal 5uperior sagittal and transverse es 9 4X2X2 Straight and superior sagittal 20 Occipitoparietal ix ix ii Superior sagittal 21 Occipitotemporal 4X4x, transverse 22 Ix ix I Superior sagittal 23 Occipitoparieral 4X 6X 7 Vein of Galen, superficial veins, dural es 24 25 Total x x ix 2X 2 Superior sagittal Superior sagittal and transverse es 25 II14 8 20 23 9 3 3 * R= right; L= left; MCA middle cerebral artery; PCA posterior cerebral artery; ECA external carotid artery; PERIC. pencallosal artery; RICA. right internal carotid artery. t No vertebral arteniography performed. ment of the groove of the posterior branch of the middle meningeal artery in all 3 instances, local thinning of the cranial vault in 2, and calcification within the malformation in I (Fig. i, ii and B). Multiple arteries supplied all but 2 of the arteriovenous malformations. The parieto_occipital, calcarine, and posterior temporal branches of the posterior cerebral artery as well as the angular branch of the middle cerebral artery were the most common contributing vessels. In each patient in whom vertebral arteriography was performed (23 of the 25 ssociated. neurysm RICA Basilar Multiple #{149} patients), it was found that branches of the posterior cerebral artery supplied the malformation (Fig. 2, zi and B; 3, ii and B; and 4, 4-D). The distal branches of the middle cerebral artery contributed to the malformation in 20 patients (Fig. 3, A and B), whereas the pericallosal artery helped to supply the angioma in 3 instances. Dural contributions via meningeal branches of the external carotid or vertebral arteries were noted in 9 patients (Fig., C and D). Venous drainage from the malformation extended into the dural es (e.g., supe-
540 B. Todd Troost and Thomas H. Newton NOVEMBER, 1974 FIG. I. Roentgenograms of the skull. (A) Roentgenogram in half-axial projection shows a localized thinning of the skull (closed arrows) with adjacent punctate calcifications (open arrows). (B) Lateral projection. The groove for the posterior branch of the middle meningeal artery is enlarged (open arrows). The localized posterior bulging and thinning of the skull vault are well shown (closed arrows). by enlarged calcanine and parieto-ocnor sagittal and transverse ) in i6 patients. The superficial veins drained the malformation in II patients. Three of the malformations drained deep into the cerebral venous system. Angiographic evidence of an intracerebral hematoma, with displacement of adjacent vessels, and an avascular zone around the arteriovenous malformation was observed in 8 of the 25 patients (Fig. 5, 4-E). DISCUSSION The roentgenographic diagnosis of arteriovenous malformation depends pri- teriovenous ma.rmation C....c medial occipital lobe is s.4 cipital branches of the right posterior cerebral artery.
VOL. 122, No. 3 Arteriovenous Malformations of the Lobe 54 arteniovenous mai ormation of r occipital lobe is supplied by enlarged branches of both the posterior and middle cerebral arteries. No field defects were seen. manly on cerebral angiography. Occasionally, however, plain roentgenograms of the skull may show signs of enlargement of the feeding arteries, calcification within the malformation, or localized erosion and bulging of the skull vault.4-0 Angiography is crucial in the diagnosis and management of intracranial arteriovenous malformations that involve the occipital lobe. Rapid serial angiography is necessary to define the ongin of the supplying arteries and the course of the draining veins. Subtraction and magnification techniques further aid in angiographic definition of these malformations. All arteries, as well as the draining veins that contribute to the malformation, must be carefully delineated if an accurate anatomic evaluation of the lesion is to be obtained. The angiographic study, therefore, should include opacification of all arteries which may supply the malformation. The exact nature and extent of the arterial supply to these malformations can be appreciated only by means of separate selective injection of contrast material into each vessel. In arteniovenous malformations of the occipital lobe, roentgenographic investigation must include selective vertebral as well as internal and external carotid arteniography. The dural contnibution to these malformations via the external carotid artery is well demonstrated in Figure 4, C and D. In this patient the malformation of the occipital pole was supplied primarily by meningeal branches of the external carotid artery. This area of the lesion is shown as a relatively avascular region in the early phases following opacification of the posterior cerebral artery. The presence of an associated intracerebral hematoma is recognized by the dis.- placement of adjacent vessels as well as by an area of avasculanity surrounding the malformation (Fig. 5, 11-E). Occasionally, the hematoma may destroy portions of the malformation. This destruction is recognized by residual enlargement of afferent arteries and draining veins (Fig., 11-E). The association of aneurysms and arteniovenous malformations is well known. Three of the patients studied had aneurysms. One aneurysm involved the distal basilar artery and one the internal carotid artery. One patient (Case 15) had 3 aneurysms on the same side as the anteniovenous malformation. In all cases reviewed, the side of the ma!- formation correlated with the contralateral visual field defect, when present. All patients with an intracenebral hematoma had
542 B. Todd Troost and Thomas H. Newton NOVEMBER, 1974. (A and B) Vertebral arteriograms, lateral projection. parieto-occipl, calcarine, and posterior temporal branches of the right posterior cerebral artery are enlarged and supply an arteniovenous malformation situated at the posterior pole of the right occipital lobe. Note area of relative avascularity in the region of the calcanine fissure (arrows) and the accompanying visual field. (C) Selective right external carotid arteriogram, lateral projection, and (D) frontal projection. The posterior branch of the middle meningeal artery is enlarged (open arrows) and supplies a small portion of the occipital lobe formation (closed arrows). a complete visual field defect. The size of ical and roentgenographic features. the malformation and the extent of the field loss, however, had no consistent re- SUMMARY lationship. Malformations of the occipital Roentgenographic and clinical features lobe comprise from 10 pen cent7 9 to 30 pen of 25 cases of arteriovenous malformations cent6 of the arteniovenous anomalies of the of the occipital lobe are summarized. brain and usually have characteristic din- apoplexy and occipital epilepsy
VOL. 522, No. 3 Arteniovenous Malformations of the Lobe 543 in - -- -- - ---- -----j - hematoma and drains into veins that empty into the adjacent superior sagittal (closed arrows). are the cardinal syndromes of occipital arteniovenous malformations. The most common presenting sign, however, is a homonymous visual field defect. Size of the malformation does not correlate with presence of visual field defect. Anteniovenous anomalies of the occipital lobe are supplied by multiple arterial sources, including distal branches of the middle cerebral artery, the posterior cerebral, external carotid, and penicallosal arteries.
544 B. Todd Troost and Thomas H. Newton NOVEMBER, 1974 Because early excision of occipital hematomas promotes recovery from visual field defects, selective arterial opacification is recommended to delineate these vascular malformations. Thomas H. Newton, M.D. Department of Radiology University of California San Francisco, California 94543 REFERENCES 1. ANDER5, R. McD., and BLACKWOOD, W. Association of arteniovenous angioma and saccular aneurysm of arteries of brain. 7. Pathol. & Bact., 1959, 77, 101-1 10. 2. BOYD-WILSON, J. S. Association of cerebral angiomas with intracranial aneurysms. 7. Neurol., Neurosurg. & Psi chiat., 1959. 22, 218-223. 3. CR0NQvI5T, S., and TROUPP, H. Intracranial anteriovenous malformation and arterial aneurysm in same patient. Acta neurol. scandinav., 1966, 42, 307-3 16. 4. Cuss-sING, H. W., and BAILEY, P. lumors Arising from the Blood-Vessels of the Brain: Anglomatous Malformations and Hemangioblastomas. Charles C Thomas, Publisher, Springfield, Ill., 1928. 5. DANDY, W. E. Anteriovenous aneurysm of brain. Arch. Surg., 1928, 17, 190-243. 6. DIMSDALE, H. Discussion on neuro-ophthalmological aspects of cerebral angiomas. Proc. Roy. Soc. Med., 1957, 50, 8-88. 7. Eiroscssos-, P., and BYNKE, H. Visual field defects in arteniovenous aneurysms of brain. Acta ophth., 1958, 36, 86-6oo. 8. NEWTON, T. H., and TROOST, B. T. Arteriovenous communications. In: Radiology of the Skull. Edited by T. H. Newton, and D. G. Potts. To be published. 9. PERRET, G., and NI5HI0KA, H. Report on cooperative study of intracranial aneurysms and subarachnoid hemorrhage. Section VI. Artenio- Venous malformations: analysis of 55 cases of cnanio-cerebral arteriovenous malformations and fistulae reported to cooperative study. 7. Neurosurg., 1966, 25, 467-490. 10. PORTER, A. J., and BULL, J. Some aspects of natural history of cerebral arteniovenous malformation. Brit. 7. Radiol., 1969, 42, 667-675. II. TROOST, B. T., and NEWTON, T. H. Migraine of arteniovenous malformation (AVM)?: clinical and roentgenographic features in 25 cases of occipital lobe AVM. Neurology, 1973, 23, 398 (Abstr.).