Neurol Med Chir (Tokyo) 51, 503¿506, 2011 Ischemic Stroke Due to Dissection of the Middle Cerebral Artery Treated by Superficial Temporal Artery-Middle Cerebral Artery Anastomosis —Case Report— Koichi TORIHASHI,1 Masaki CHIN,1 Nobutake SADAMASA,1 Kazumichi YOSHIDA,2 Osamu NARUMI,1 and Sen YAMAGATA1 1Department of Neurosurgery, Kurashiki Central Hospital, Kurashiki, Okayama; 2Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto Abstract A 62-year-old man presented with dissection of the right middle cerebral artery (MCA) manifesting as mild headache, right hemiparesis, and slurred speech. Magnetic resonance (MR) imaging and MR angiography revealed fresh infarction in the right basal ganglia, and severe stenosis and dilatation of the right MCA. Digital subtraction angiography approximately 24 hours after admission revealed a linear contrast defect indicating an intimal flap of the M1 segment. The diagnosis was dissection of the MCA. His neurological deficits improved gradually. Although he was neurologically stable, diffusion-weighted MR imaging revealed enlarging infarct size over the right MCA territory, and the right M1 segment had progressive stenosis. Superficial temporal artery (STA)-MCA anastomosis was performed on the 26th day. Follow-up angiography showed good patency of the STA-MCA anastomosis, repair of the dissection of the M1 segment, and improvement of the flow in the MCA. The patient was discharged from our hospital with no neurological deficits. Although the dissection in this case was spontaneously repaired, STA-MCA anastomosis was useful to get through a critical time. If the stenosis shows further progression or the infarction size enlarges, STA-MCA anastomosis may be effective. Key words: cerebral infarction, middle cerebral artery, dissection, superficial temporal artery-middle cerebral artery anastomosis, magnetic resonance angiography Introduction We report a rare case of rapidly progressive ischemic stroke caused by dissection of the right MCA in a patient who underwent superficial temporal artery (STA)-MCA anastomosis. Progression of the dissection was demonstrated by magnetic resonance (MR) imaging, MR angiography, computed tomography (CT) angiography, digital subtraction (DS) angiography, and single photon emission computed tomography (SPECT). Arterial dissection in the anterior circulation is relatively rare compared with the posterior circulation, but often results in severe morbidity or mortality due to cerebral infarction or hemorrhage.1,5,6,12,15,17,19) Arterial dissections of the anterior circulation can also cause subarachnoid hemorrhage (SAH),5,12,21) may be associated with cerebral ischemia, and result in complete stroke due to arterial stenosis or occlusion. Cerebral artery dissection may be responsible for ischemic events in children.2) Dissection of the middle cerebral artery (MCA) has been increasingly reported in recent years. The typical initial clinical symptoms are sudden appearance of headache, hemiparesis, dysarthria, and disturbance of consciousness with hemispheric functional loss. The natural course of this dissection remains unclear and the surgical indications for this type of dissection with ischemic onset are controversial. Bypass surgery has been proposed in selected patients, but the clinical application is not well defined.7,16,22,23) Received November 4, 2010; Accepted Case Report A 62-year-old man presented to our emergency department after noticing mild headache, right hemiparesis, and slurred speech. He had previously been healthy with no history of head injury. MR imaging, MR angiography, and CT angiography were taken 6 hours after onset. Diffusionweighted MR imaging revealed fresh infarction in the right basal ganglia (Fig. 1A). MR angiography and CT angiography showed the right M1 segment was severely stenotic and T2*-weighted MR imaging revealed a dilatation (Fig. 1B, C). Perfusion CT showed no decrease in cerebral blood flow (CBF) in the right hemisphere. DS angiography approximately 24 hours after admission rev- December 28, 2010 503 504 K. Torihashi et al. Fig. 1 A: Diffusion-weighted magnetic resonance (MR) image on the day of admission showing fresh infarction in the right basal ganglia. B: T2*-weighted MR image on admission revealing a dilatation (arrow) of the right middle cerebral artery (MCA). C: MR angiogram on admission showing severe stenosis (arrow) in the right MCA. D: First right carotid angiogram approximately 24 hours after admission revealing a linear contrast defect (arrow) indicating an intimal flap from the proximal to the distal portions of the M1 segment. ealed a linear contrast defect indicating an intimal flap from the proximal to the distal portions of the M1 segment (Fig. 1D). Based on these findings, the diagnosis was dissection of the right MCA. He was administered aspirin 100 mg/day orally. On the day after admission, he was beginning to show some improvement in speech and motor function. His neurological deficits improved gradually. MR angiography on the 7th day after admission revealed progress of the stenosis in the M1 segment (Fig. 2A). Although he was neurologically stable, diffusion-weighted MR imaging on the 21st day after admission revealed enlarging infarct size over the right MCA territory, and progressive stenosis in the right M1 segment, gradually delaying the flow of the MCA as seen on MR, CT, and DS angiography (Fig. 2B–D). SPECT demonstrated decreased CBF at rest (Ã30 ml/100 g/min) and reduced reactivity to acetazolamide (cerebral blood volume [CVR] Ã10%) in the right parietal and temporal lobes (Fig. 3A). To prevent further aggravation of the infarction due to the progressive dissection, we performed double STA-MCA anastomosis on the 26th day. The postoperative course was uneventful and no neurological deficits occurred. Diffusion-weighted MR imaging on the 17th day after the procedure revealed no enlargement of the infarction and MR angiography revealed im- Fig. 2 A, B: Magnetic resonance (MR) angiograms obtained on days 7 and 19 showing progressive stenosis of the right M1 segment gradually delaying the flow of the middle cerebral artery (MCA). C: Diffusion-weighted MR image on the 21st day after admission revealed enlarging infarct size over the right MCA territory. D: Right carotid angiogram obtained on day 23 showing progressive stenosis in the right M1 segment causing delay of flow in the MCA. provement of the stenosis of the MCA (Fig. 4A). Follow-up angiography on the 18th day after surgery showed good patency of the STA-MCA anastomosis, repair of the dissection of the M1 segment, and improvement of the flow of the MCA (Fig. 4B, C). SPECT showed improved CBF and CVR in the right temporal and parietal lobes (Fig. 3B). He was discharged from our hospital with no neurological deficit on the 23rd day after the procedure. Discussion The characteristics of the present case that led to the diagnosis of arterial dissection were: occurrence in a young adult, headache as an initial symptom, intimal flap with direct evidence on angiography, and structural change from stenosis to occlusion within a short period.4,8,11,17) Angiographic demonstration of an intimal flap, false lumen, or pseudoaneurysm is relatively uncommon. Dissection of the MCA generally occurs at the sphenoidal portion (M1 segment), and typically branch dissection is a consecutive lesion from the M1 segment.17) If dissection of the MCA is suspected, diagnostic examinations and DS angiography should be performed immediately because of the possibility of dynamic changes over a Neurol Med Chir (Tokyo) 51, July, 2011 Dissection of the MCA 505 º Fig. 3 A: Single photon emission computed tomography (SPECT) scans on the 21st day after admission showing decreased cerebral blood flow (CBF) at rest (Ã30 ml/100 g/min) and reduced reactivity to acetazolamide (cerebral blood volume [CVR] Ã10%) in the right parietal and temporal lobes. B: SPECT scans on the 42nd day after admission (16th day after surgery) showing improved CBF and CVR in the right temporal and parietal lobes. Fig. 4 A: Magnetic resonance angiogram on day 43 (17th day after surgery) revealing good patency of the superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis and improvement of the stenosis of the MCA. B, C: Right carotid angiograms on day 44 (18th day after surgery) showing good patency of the STA-MCA anastomosis, repair of the dissection of the M1 segment, and improvement of the flow of the MCA. short time.8) Although surgical treatment such as wrapping, coating, or trapping may be appropriate in the presence of SAH, the treatment for ischemic symptoms remains controversial since subsequent bleeding often leads to poor outcomes. Extensive lesions of dissection seen on angiography have resulted in a wide range of cerebral infarction and poor prognosis.10) Infarction was observed not only in the territory of the MCA branches but also in the territory of the lenticulostriate artery originating from the M1 segment.17) Medication used for infarction due to other causes, such as fibrinolytic drugs, and anticoagulant or antiplatelet drugs, might not be effective for arterial stenosis caused by dissection. Administration of these drugs may also increase the risk of SAH at the dissection. Anticoagulants may be harmful in these patients because of the risk of hemorrhagic transformation or even progressive dissection.20) Intracranial dissection with ischemic onset may bleed at the next attack.14,24) Most patients with acute ischemic change with dissection had poor outcome with Neurol Med Chir (Tokyo) 51, July, 2011 conventional intravenous recombinant tissue plasminogen activator thrombolysis treatment.9) The optimum medical treatment for infarction due to dissection has not been established and should be clarified. Surgical treatment such as trapping and STA-MCA anastomosis may be considered if the MCA dissection involves cerebral infarction. Three of four patients with the natural course deteriorated with cerebral infarction due to MCA dissection and made a poor recovery, with neurological deficits, such as hemiparesis, caused by infarct.7) Five of seven patients with MCA dissection and ischemia who were treated conservatively subsequently died.8) In contrast, outcomes in surgically treated patients were relatively good. Patients with MCA dissection had sudden aggravations after 7 to 15 days of uneventful acute course after the first attack due to recurrent attacks as determined by clinical and imaging findings.18) If follow-up angiography indicates progress of the dissection or the clinical symptoms deteriorate, surgery should be performed immediately. Endovascular treatment for internal carotid artery dissection can be successful, but the problem of perforators presents difficulties in MCA dissection.13) A case of MCA occlusion due to dissection was successfully treated by intra-arterial fibrinolysis.3) Despite the risk of hemorrhage, the endovascular technique may be considered in high risk patients undergoing direct surgery. Our patient was discharged with no neurological deficits during treatment or follow up, but the infarction enlarged and the CBF decreased because of progress of the M1 stenosis. Close observation with DS angiography, MR angiography, and SPECT for any clinical symptoms, including mild headache and temporary neurological deficits, is essential. Noninvasive MR imaging and MR angiography are useful for follow up of the dissection. Although the dissection in this case was spontaneously repaired, the STA-MCA anastomosis was useful to get through a critical time. The present case suggests that careful follow-up serial angiography and MR imaging/angiography will be necessary because the dissection of the MCA may progress. If the MCA dissection involves cerebral infarction and is lo- K. Torihashi et al. 506 cated at a proximal site on a major branch, surgical treatment must be considered.8) If the stenosis shows progression, the infarction size is enlarged or CBF is decreased, STA-MCA anastomosis may be effective. References 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) Abiko S, Okamura T, Kurokawa Y, Ikeda N, Ideguchi M, Watanabe K: [Diagnosis and treatment of nontraumatic dissecting aneurysm in the middle cerebral artery]. No Shinkei Geka 27: 743–749, 1999 (Japanese) Chabrier S, Lasjaunias P, Husson B, Landrieu P, Tardieu M: Ischaemic stroke from dissection of the craniocervical arteries in childhood: report of 12 patients. Eur J Paediatr Neurol 7: 39–42, 2003 Fu Y, Komiyama M, Inoue T, Ohata K, Matsuoka Y, Hakuba A: [A case of middle cerebral artery occlusion caused by dissecting aneurysm]. No Shinkei Geka 24: 955–959, 1996 (Japanese) Grosman H, Fornasier VL, Bonder D, Livingston KE, Platts ME: Dissecting aneurysm of the cerebral arteries. Case report. J Neurosurg 53: 693–697, 1980 Hashimoto H, Iida J, Shin Y, Hironaka Y, Sakaki T: Subarachnoid hemorrhage from intracranial dissecting aneurysms of the anterior circulation. Two case reports. Neurol Med Chir (Tokyo) 39: 442–446, 1999 Kawaguchi T, Kawano T, Kazekawa K, Honma T, Kaneko Y, Koizumi T, Dousaka Y: [Dissecting aneurysm of the middle cerebral artery with subarachnoid hemorrhage and brain infarction: a case report]. No Shinkei Geka 25: 1033–1037, 1997 (Japanese) Kitani R, Itouji T, Noda Y, Kimura M, Uchida S: Dissecting aneurysms of the anterior circle of Willis arteries. Report of two cases. J Neurosurg 67: 296–300, 1987 Kurino M, Yoshioka S, Ushio Y: Spontaneous dissecting aneurysms of anterior and middle cerebral artery associated with brain infarction: a case report and review of the literature. Surg Neurol 57: 428–436, 2002 Lavall áee PC, Mazighi M, Saint-Maurice JP, Meseguer E, Abboud H, Klein IF, Houdart E, Amarenco P: Stent-assisted endovascular thrombolysis versus intravenous thrombolysis in internal carotid artery dissection with tandem internal carotid and middle cerebral artery occlusion. Stroke 38: 2270–2274, 2007 Lin CH, Jeng JS, Yip PK: Middle cerebral artery dissections: differences between isolated and extended dissections of internal carotid artery. J Neurol Sci 235: 37–44, 2005 Mizutani T: Middle cerebral artery dissecting aneurysm with persistent patent pseudolumen. Case report. J Neurosurg 84: 267–268, 1996 12) 13) 14) 15) 16) 17) 18) 19) 20) 21) 22) 23) 24) Mizutani T: Subarachnoid hemorrhage associated with angiographic ``stenotic'' or ``occlusive'' lesions in the carotid circulation. Surg Neurol 49: 495–503, 1998 Mourand I, Brunel H, Vendrell JF, Thouvenot E, Bonaf áe A: Endovascular stent-assisted thrombolysis in acute occlusive carotid artery dissection. Neuroradiology 52: 135–140, 2010 Naito I, Iwai T, Sasaki T: Management of intracranial vertebral artery dissections initially presenting without subarachnoid hemorrhage. Neurosurgery 51: 930–937, 2002 Nimura T, Oku T, Narita N, Higuchi H: [Dissecting aneurysm of the middle cerebral artery: case report]. No Shinkei Geka 28: 61–65, 2000 (Japanese) Ohkuma H, Suzuki S, Ogane K; Study Group of the Association of Cerebrovascular Disease in Tohoku, Japan: Dissecting aneurysms of intracranial carotid circulation. Stroke 33: 941–947, 2002 Ohkuma H, Suzuki S, Shimamura N, Nakano T: Dissecting aneurysms of the middle cerebral artery: neuroradiological and clinical features. Neuroradiology 45: 143–148, 2003 Oka F, Shimizu H, Matsumoto Y, Watanabe M, Tominaga T: Ischemic stroke due to dissection of intracranial internal carotid artery: implications for early surgical treatment. Surg Neurol 69: 578–584, 2008 Ono Y, Kawamura T, Ito J, Kanayama S: [Dissecting aneurysm of the middle cerebral artery (M1–2 portion) with subarachnoid hemorrhage: a case report]. No Shinkei Geka 29: 347–352, 2001 (Japanese) Piepgras D, McGrail KM, Tazelaar HD: Intracranial dissection of the distal middle cerebral artery as uncommon cause of distal cerebral artery. J Neurosurg 80: 909–913, 1994 Sasaki O, Koike T, Tanaka R, Ogawa H: Subarachnoid hemorrhage from a dissecting aneurysm of the middle cerebral artery. Case report. J Neurosurg 74: 504–507, 1991 Schievink WI, Mokri B, Piepgras DG: Spontaneous dissections of cervicocephalic arteries in childhood and adolescence. Neurology 44: 1607–1612, 1994 Steiner H, Lammer J, Kleinert R, Schreyer H: Dissecting aneurysm of cerebral arteries in congenital vascular deficiency. Neuroradiology 28: 331–334, 1986 Tsutsumi M, Kawano T, Kawaguchi T, Kaneko Y, Ooigawa H: Dissecting aneurysm of the vertebral artery causing subarachnoid hemorrhage after non-hemorrhagic infarction—case report. Neurol Med Chir (Tokyo) 40: 628–631, 2000 Address reprint requests to: Koichi Torihashi, MD, Department of Neurosurgery, Kurashiki Central Hospital, 1–1–1 Miwa, Kurashiki, Okayama 710–8602, Japan. e-mail: kt10472@kchnet.or.jp Neurol Med Chir (Tokyo) 51, July, 2011