Megadolicho vascular malformation of the intracranial arteries

MEGADOLICHO VASCULAR MALFORMATION OF THE INTRACRANIAL ARTERIES J. Lodder*, B. Janevski** and P.J.M. van der Lugt*

SUMMARY A patient is presented suffering a hemiparesis. Megadolicho-vascular malformation of the intracranial part of the internal carotid arteries and some of its branches and of the basilar artery was suggested by CT and confirmed by angiography. The value of CT compared with angiography in relation to intracranial megadolicho vascular malformations is discussed.

INTRODUCTION

Vertebral angiography has classically been regarded as obligatory to establish megadolicho malformation of the basilar artery (AZAR-RIA et al., 1976). Recent reports indicate that CT may suffice to diagnose this vascular anomaly (DEEB et al., 1979; MOSELYand HOLLAND, 1979; PETERSONet al., 1977; SCOTTIet aL, 1978). After careful study of the literature it became clear that some discrepancies between CT and angiographic findings cannot be ignored, especially as regards detection of ectasia of the major bratlches of the vertebrobasilar system as well as of the intracranial part of the internal cerebral arteries and their branches. We now present a patient suffering a hemiparesis, with ectasia of the basilar artery and of the internal cerebral arteries and some of their branches. The anomaly was suggested by CT and confirmed by angiography. CASE REPORT

A 67 year old man, who had been receiving ambulatory treatment with a diuretic because of hypertension, was admitted because he experienced weakness in his right arm and leg. On examination he exhibited dysarthric speech and a slight motor dysphasia. A right-sided central facial nerve paresis was established. Muscular weakness of the arm and the leg on the same side was also noticed. Plantar reflexes were extensor bilaterally. Routine blood chemistry was normal, as were X-rays of * Department of Neurology, ** Department of Radiology. St. Annadal Hospital, Medical Faculty. University of Limburg, Maastricht, The Netherlands. Clin. NeuroI. Neurosurg. 1981.Vol. 83-1,(accepted 13.2.81)

12

Fig. 1. CT. A. Native scan demonstrates a homogeneous round density posterior to dorsum sellae, projecting into the right pontine cistern. B. After intravenous contrast medium the lesion presents as a dense round mass suggesting an aneurysm or a dilated artery, reaching the level o f the third ventricle.

Fig. 2. CT. A. Native scan shows a comma-shaped high-density region on the right side of the pentagon and a small linear density on the left side projecting in the Sylvian cistern. B. Intense enhancement after contrast injection. The lesion suggests dilated vessels at the base of the brain, which is confirmed by angiography in Figs. 4 and 5.

13

Fig. 3. Vertebrobasilarangiography. A. Frontal projection. Fusiform dilatation and elongation of the third and fourth segment of the left vertebral artery and the whole basilar artery. Slight dilatation of the posterior cerebral arteries. B. Lateral projection.The upper end of the basilar artery projects 2 cm above the dorsum sellae, because of extreme elongation. the skull and the thorax. ECG showed minor aberrations. EEG as well as Doppler hematographic examination o f the precerebral vessels were normal. CSF chemistry was normal. CSF tests for syphilis were negative as were yeast and fungi cultures. Radio-nuclide brain scanning did not show focal lesions. The native CT scans of the base of the brain indicated a homogeneous rounded density projecting into the right pontine cistern posteriorly to the dorsum sellae (Fig. la) and two other curvilinear densities on both sides of the pentagon (Fig. 2a). Administration o f contrast medium resulted in an increased X-ray attenuation o f these lesions which subsequently appeared as well defined, rounded (Fig. lb) and elongated curvilinear densities (Fig. 2b). CT findings suggested an aneurysmal dilatation of the arteries near the circle of Willis, that is to say, of the middle cerebral artery on both sides, the distal portion o f both internal carotid arteries (ICA) and of the basilar artery (BA). The basilar artery also showed an exceptional elongation but there were no signs of compression of the third ventricle with subsequent hydrocephalus, since the size of the lateral ventricles was compatible with age. The transfemoral catheterization technique was used for aortic arch aortography and selective studies o f the carotid and vertebral arteries. The arteriograms indicated a fusiform dilatation and elongation o f the major intracranial arteries. The third and fourth segments o f the left vertebral artery and the whole basilar artery were fairly uniformly dilated (Fig. 3a en 3b). The posterior cerebral arteries were

14

Fig. 4. Left carotid angiography A. Frontal view, and B. Lateral view. Marked dilatation of the intracranial portion of the left internal carotid artery with extension into the middle cerebral artery. The dilated arteries are irregular. Note also a circular stenosis at the origin of the anterior cerebral artery (arrow) with slight post-stenotic dilatation.

also slightly dilated. The terminal cerebral and all cerebellar arteries were normal. On lateral projection a marked elongation of the basilar artery was seen. The distal end of this artery was projected 2 cmcranially to the dorsum sellae. Bony abnormalities of the dorsum or clivus were not observed. The left carotid arteriogram revealed dilatation of the intracranial portion of the ICA extending to the middle cerebral artery (Fig. 4a and 4b). The dilated segment showed an irregular calibre. In addition to this, there was a circular stenosis and a slight post-stenotic dilatation of the proximal portion of the left anterior cerebral artery. The right carotid arteriogram demonstrated involvement only of the upper end of the right internal carotid artery, which was markedly dilated and irregular (Fig. 5a and 5b). The right middle cerebral artery was also dilated. The right anterior cerebral artery was normal. DISCUSSION

Megadolicho anomaly of the basilar artery is most prevalent in males over the age of fifty (MOSELYand HOLLAND, 1979). Occurrence in younger people has been described and consequently is regarded by some as congenital in origin (FERRY et al., 1974; HEIDRICH and SCHREIBER, 1970; JOHNSON 81 al., 1977; SACKS and LINDENBURG,

15

Fig. 5. Right carotid angiogram A. Frontal, and B. Lateral view. Fusiform dilatation only of the upper end of the right internal carotid artery and moderate dilatation of the middle cerebral artery.

1969; SCOTTIet al., 1978; VOIGT et aL, 1973). Arteriosclerosis (BOERI and PASSERINI, 1964; HEINDRICHand SCHREIBER, 1970; MOSELYand HOLLAND, 1979; WALLACEand JAFFE, 1967) frequently with simultaneous hypertension (HAYES e t al., 1967; HULTI~N-GYLLENSTENet al., 1959) was considered to be a major cause. It has also been suggested that vascular inflammation caused by yeasts, fungi or syphilis may also play a role (JOHNSON et al., 1977; WALLACEand JAFFE, 1967). Moreover, ectasia of intracranial arteries has been reported in patients with Anderson-Fabry disease (MAISY and COSH, 1980; WALLACE, 1973). The present patient fits well into the category of elderly, hypertensive males; signs of inflammation of mycological or syphilitic origin could however not be detected. Ectasia of the basilar artery may give rise to symptoms consistent with the diagnosis o f a pseudotumor in the posterior fossa (AZAR-KIA et al., 1976; FRASSONet al., 1977; HAYESet al., 1967) or may result in cranial nerve compression (AZAR-KIA et al., 1976; BOERI and PASSERINI, 1964; DEEBet al., 1979; HAMMER, 1979; HAYESet al., 1967; HOPKINS and POSER, 1973; KERBERet al., 1972; KRAMERand ECKMAN, 1972; NAPPIet al., 1977; SCOTT and STAUFFER, 1964). Brain stem symptoms (aOERX and PASSERINI, 1964; DEEB et al., 1979; HAMMER, 1979; MAISEY and COSH, 1980) and obstructive hydrocephalus due to compression of an extending basilar artery into the floor of the third ventricle have also been reported (BREIGet al., 1976; DEEBet al.,

16 1979; MA1SEYand COSH, 1980; ROZARIO et al., 1978; sCOTn et al., 1978). Little is known of the survival prognosis. Severe bulbar involvement may lead to death (HAUY~S et al., 1967; MOSELYand HOLLAND, 1979), though rupture and subsequent bleeding are considered unlikely (BOERI and PASSERINI, 1964; HEIDRICH and SCHREIBER, 1970; PETERSON e t a / . , 1977). Some authors have stated that simultaneous involvement of the carotid arteries in case of megadolicho malformation of the basilar artery is often seen though no evidence is given (BOERI and PASSERINI, 1964; PETERSON et al., 1977; SCOTTI et al., 1978). According to Mosely, however, unlike the involvement of the posterior cerebral arteries, the intracranial part of the internal carotid arteries and its branches are infrequently involved, whereas megadolicho malformation of the precerebral part is more common (SCHECHTER, 1979). By contrast with the frequency of symptoms caused by the megadolicho malformation of the basilar artery, specific symptoms due to involvement of the intracranial part of the ICA or its branches is scarcely mentioned. In two of such cases hemiparesis resulting from cortical lesions was described (HULTI~N-GYLLENSTEINet al., 1959; TAPTAS, 1948). The present patient also had a hemiparesis as a result of a cortical lesion, which gave rise to slight dysphasia, though CT and radio-nuclide brain scans were not indicative of cerebral infarction. Visual disturbances caused by ectatic ICA compressing the optic chiasm are well known (MITTS and MCQUEEN, 1965) and a superior orbital fissure syndrome has also been described (CALLIAUW and DEBERDT, 1966). Since the clinical picture of megadolicho anomaly of cerebral arteries varies, proper diagnosis cannot be made on clinical grounds (MOSELYand HOLLAND, 1979; NAPPI et al., 1977). Angiography has been regarded as obligatory to establish the anomaly (BOERI and PASSERINI, 1964). Some authors, however, argue that CT may be sufficient and that it is acceptable to refrain from angiography when such an anomaly is suggested (HAMMER, 1979; MOSELYand HOLLAND, 1979; PETERSONet al., 1977; SCOTTI et al., 1978). We agree with this view as far as the basilar artery is concerned since in 10 cases (DEEB, 1979; HAMMER, 1979; HIRSCH and GONZALES, 1979; PETERSONet a/., 1977) CT findings were simply confirmed by angiography. In one case, however, megadolicho malformation of the basilar artery was revealed angiographically even though CT findings were negative (WAGAet al., 1979). With respect to the other major arteries in the posterior fossa and the posterior cerebral arteries, it is quite obvious that anomalies are more frequently discovered by angiography than by CT: ectasia of the vertebral arteries (DEEB et al., 1979) posterior inferior cerebellar arteries (SCOTTIet al., 1978), superior cerebellar arteries (MOSELY and HOLLAND, 1979; SCOTTI et al., 1978) and posterior cerebral arteries (DEEB el al., 1979, MOSELYand HOLLAND, 1979; SCOTTIet al., 1978) was revealed by angiogl'aphy though CT gave no indication of these anomalies. In the present case as well dilatation of one of the vertebral arteries and posterior cerebral arteries was only visible on angiography. Ectasia of the first part of the right posterior cerebral artery (HAMMER, 1979) and of the intracranial part of both ICA (MOSELYand HOLLAND, 1979; SCOTTI et al., 1978) which was indicated by CT was not confirmed by angiography, indicating that

17

false positive images may occur on CT. On the other hand elongation and tortuosity of the ICA and its branches were missed by CT (WAGA e t al., 1979). Thus, caution is to be advocated as regards employing CT only for establishing or ruling out ectasia of some of the major branches of the vertebrobasilar as well as the carotid system, especially since carotid angiography is often not performed in case of megadolicho malformation of the basilar artery. The possibility that simultaneous involvement of the ICA is more frequent is thus not excluded. CT findings suggesting megadolicho malformation of both basilar artery and ICA were compatible with angiography findings in only two cases (HAMMER, 1979; MOSELYand HOLLAND, 1979). We now add a third case in whom ectasia of both ICA and the middle cerebral arteries was succesfully demonstrated by CT. It may be concluded that megadolicho vascular anomaly of the basilar artery can clearly be detected by CT alone. However, for the purpose of establishing ectasia of the vertebral arteries and the major branches of the vertebrobasilar system angiography is required. It is possible to detect ectasia of the intracranial part of the ICA and its branches by CT, though, angiographic confirmation is indicated. Angiography should be performed in patients suffering from focal cortical ischemia in which CT indicates megadolicho malformation of the basilar artery with the main objective of ruling out megadolicho malformation of the internal carotid artery system as a source of possible emboli. REFERENCES AZAR-KIA, B., E. PALACIOS a n d M. SPOK (1976) The megadolichobasilar artery anomaly and expansion of the internal auditory meatus. N e u r o r a d i o l o g y I l: 109. BOERI, R. a n d A. PASSERINI(1964) The megadolichobasilar anomaly. J. Neurol. Sci. 1:475. BREIG, A., K. EKBOM, T. GREITZ a n d E. KUGELBERG (1976) H y d r o c e p h a l u s d u e to elongated basilar artery. The Lancet i:874. CALLIAUW, L. a n d R. DEBERDT(1966) T h e s u p e r i o r orbital fissure syndrome secondary to dolicho-megacarotid artery. Psychiat. Neurol. N e u r o s u r g . 69:149. DEEB, Z.L., P.J. JANETTA, A.E. ROSENBAUM, C.W. KERBER a n d B.P. DRAYER (1979) T o r t u o u s vertebrobasilar

arteries causing cranial nerve syndromes: screening by computed tomography. J. Comput. Assist. Tomogr. 3 (6):774. FERRY, P.C., C. KERBER, D. PETERSON a n d A.A. GALLO (1974) A r t e r y ectasis, subarachnoid hemorrhage in a three-month-old infant. N e u r o l o g y 24:494. FRASSON, F., G. FERRARI, C. FUGAZZOLA a n d A. FIASCHI (1977) Megadolichobasilar anomaly causing a brainstem syndrome. N e u r o r a d i o l o g y 13:279. HAMMER, B. (1979) Computertomographische Diagnose der Megadolichobasilaris. Fortschr. R6ntgenstr. 131:255. HAYES, W.T., H. BERNHARDT a n d J.M. YOUNG (1967) Fusiform arteriosclerotic aneurysm of the basilar artery. Vasc. Surg. I: 171. HEIDRICH, R. a n d D. SCHREtBER (1970) Arterioven6ses Angiom, Megadolichobasilaris und Fehlbildungen am Circulus arteriosus Willisii. Psychiat. Neurol. u n d Med. Psychol. (Lpz) 22: 177. mRSCH, L.F. a n d C.F. GONZALES (1979) F u s i f o r m basilar aneurysm simulating carotid transient ischemic attacks. S t r o k e 10:598. HOPKINS, E.W. a n d C.M. POSER (1973) Posterior a r t e r y ectasia. A n u n u s u a l cause ofophthalmoplegia. Arch. N e u r o l . 29:279. HULTI~N-GYLLENSTEIN, I-L., S. LOFSTEDT a n d o. VON REIS (1959) Observations on generalized arteriectasis. Acta Med. Scand. 163:125. ~OHNSON, S.D., G. OKAMOTO a n d J. KOOIKER (1977) Fusiform basilar artery aneurysm in a child. N e u r o l o g y 27:334.

18 KERBER, C.W., M.T.MARGOLISand T.H. NEWTON (1972) Tortuous vertebrobasilar system: a cause o f cranial nerve signs. Neuroradiology 4:74. KRAMER, R.A. and I'.B. ECKMAN (1972) Hemifacial spasm associated with redundancy of the vertebral artery. Am. J. Roentgenol. 115: 133. MAXSV, D.W. and J.A. COSH (1980) Basilar artery aneurysm and Anderson-Fabry disease. J. Neurol. Neurosurg. Psychiat. 43:85. Mrrrs, M.G. and J.D. MCQUEEN (1965) Visual loss associated with fusiform enlargement of the intracranial portion of the internal carotid artery. Neurosurgery 23:33. MOSELY,I.F. and l.M. HOLLAND (1979) Ectasia o f the basilar artery: the breadth o f the clinical spectrum and the diagnostic value o f computed tomography. Neuroradiology 18:83. NAPPI, G., A. MOGLIA, M. POLONI and A. ARRIGO (1977) Hemifacial spasm associated with dolichomegavertebralis anomaly. Eur. Neurol. 15:94. PETERSON, N.T., P.M. DUCHESNEAU, E.L. WESTBROOK and M.A. WEINSTEIN (1977) Basilar artery ectasia demonstrated by computed tomography. Radiology 122:713. ROZARIO, R.A., H.L. LEVINE and R.M. s c o r r (1978) Obstructive hydrocephalus secondary to an ectatic basilar artery. Surg. Neurol. 9:3 I. SACKS, J.G. and R. LINDENBURG (1969) Dolicho-ectatic intracranial arteries: symptomatology and pathogenesis of arterial elongation and distension. John Hopkins Med. J. 125:95. SCHECHTER, D.C. (1979) Dolichocarotid syndrome. Cerebral ischemia related to cervical carotid artery redundancy with kinking: Part. I. New York State J. Med. 79:1391. SCOTT, M. and H.M. STAUFFER (1964) A case of aneurysmal malformation of the vertebral and basilar arteries causing cranial nerve involvement. Am. J. Roentgenol. 92:836. SCOTTI, G., C. DE GRANDI and A. COLOMBO (1978) Ectasia of the intracranial arteries diagnosed by computed tomography. Megadolicho basilar artery: CT diagnosis. Neuroradiology 13:183. SCOTTI, G., D. MELANqON and A. OLIVER (1978) Hypoglossal paralysis due to compression by a tortuous, internal carotid artery in the neck. Neuroradiology 14:263. TAPTAS, J.-N. (1948) Les dilitations et allongements de I'art~re carotide interne, l~tats fonctionnelles et organiques. Rev. Neurol. 80:338. VOtGr, K, H. BECK and G. REINSHAGEN (1973) A complex cerebral vascular malformation studied by angiography: multiple aneurysms, angiomas and arterial ectasia. Neuroradiology 5:117. WAGA, S., A. MORtKAWAand T. KOJXMA(1979) Trigeminal neuralgia: compression o f the trigeminal nerve by an elongated and dilated basilar artery. Surg. Neurol. 1 I: 13. WALLACE, S. and M.E. JAFFE (1967) Cerebral arterial ectasia with saccular aneurysms. Radiology 88:90. WALLACE, H.J. (1973) Anderson-Fabry disease. Brith.J.Dermatol. 88:1.