Hiroshi Midorikawa

Distinctive flow pattern of wall shear stress and oscillatory shear index: similarity and dissimilarity in ruptured and unruptured cerebral aneurysm blebs

OBJECT The difference in the hemodynamics of wall shear stress (WSS) and oscillatory shear index (OSI) between ruptured and unruptured aneurysms is not well understood. The authors investigated the hemodynamic similarities and dissimilarities in ruptured and thin-walled unruptured aneurysm blebs. METHODS Magnetic resonance imaging-based fluid dynamics analysis was used to calculate WSS and OSI, and hemodynamic and intraoperative findings were compared. The authors also compared ruptured and unruptured thin-walled blebs for the magnitude of WSS and OSI. RESULTS Intraoperatively, 13 ruptured and 139 thin-walled unruptured aneurysm blebs were identified. Twelve of the ruptured (92.3%) and 124 of the unruptured blebs (89.2%) manifested low WSS and high OSI. The degree of WSS was significantly lower in ruptured (0.49 ± 0.12 Pa) than in unruptured (0.64 ± 0.15 Pa; p < 0.01) blebs. CONCLUSIONS Ruptured and unruptured blebs shared a distinctive pattern of low WSS and high OSI. The degree of WSS at the rupture site was significantly lower than in the unruptured thin-walled blebs.

Efficacy of middle meningeal artery embolization in the treatment of refractory chronic subdural hematoma

Background: There are no established treatment procedures for repeatedly recurring chronic subdural hematoma (CSH). In this study, we discussed the efficacy of middle meningeal artery (MMA) embolization in preventing recurrence of CSH. Methods: We performed superselective angiography of MMA in four patients who suffered from repeated recurrence of CSH. After angiography, we performed embolization of MMA with endovascular procedure. Results: In all cases, superselective angiography of MMA revealed diffuse abnormal vascular stains that seemed to represent the macrocapillaries in the outer membrane of CSH. In all the patients, there were no recurrences or enlargements of CSH after the embolization of the MMA. Conclusion: MMA embolization can be an effective adjuvant procedure in preventing the recurrence of CSH.

Optochiasmal arachnoiditis following cotton wrapping of anterior communicating artery aneurysm treated by surgical removal of granuloma.

We report the case of a 50 year old female who presented with visual disturbance due to optochiasmal arachnoiditis and foreign body granuloma 9 months after cotton wrapping for ruptured anterior communicating artery (AcomA) aneurysm. Magnetic resonance imaging (MRI) revealed enhanced mass lesion around AcomA complex and hyperintense signal on optic chiasm and right optic tract by fluid-attenuated inversion recovery image. Despite the repeated steroid pulse therapy, she deteriorated and MRI showed expansion of the granulomatous lesion over 5 months. Surgical removal of foreign body granuloma resulted in marked improvement of visual disturbance as well as of the MRI findings. We conclude that the use of cotton sheet close to the optic nerve should be avoided, and that surgical removal of the granuloma would be the optimal choice especially for the patient in whom steroid therapy fails to improve clinical symptoms.

Vertebrobasilar artery dissection presenting with simultaneous subarachnoid hemorrhage and brain stem infarction: case report.

BACKGROUND Intracranial dissecting aneurysms have been associated with subarachnoid hemorrhage (SAH) or cerebral ischemia. We encountered a patient presenting with simultaneous subarachnoid hemorrhage and brainstem infarction caused by a dissecting aneurysm of the vertebrobasilar artery, which was diagnosed by magnetic resonance imaging (MRI) but did not show abnormal findings on cerebral angiography. CASE DESCRIPTION A 55-year-old man had sudden onset of headache and left abducens palsy. Computed tomography revealed a subarachnoid hemorrhage localized in the left prepontine cistern and the left cerebellomedullary fissure. Cerebral angiography showed neither a saccular aneurysm nor fusiform dilatation causing the subarachnoid hemorrhage. MRI demonstrated a small infarction in the left dorsal pons, and an intramural hematoma of the left vertebral artery and lower basilar artery. CONCLUSION This is a rare case of a vertebrobasilar dissecting aneurysm that simultaneously caused both SAH and brain stem infarction. MRI should be performed in the acute phase of SAH of unknown origin to determine the possible coexistence of a dissecting aneurysm, as occurred in this case.

Effectiveness of intraarterial administration of fasudil hydrochloride for preventing symptomatic vasospasm after subarachnoid hemorrhage.

OBJECTIVE We examined the effect of intraarterial administration of fasudil hydrochloride (IAFC), a Rho kinase inhibitor, for the prevention of symptomatic vasospasm after SAH by evaluating cerebral circulation. METHODS We evaluated IAFC cases of 57 sides of 38 patients (12 men and 26 women, average age 60.2 years old) diagnosed with aneurysmal subarachnoid hemorrhage (SAH) from February 2012 to November 2012. All cases were treated by clipping or coil embolization within 48 h after onset. Indication for IAFC was the existence of a spastic change on follow-up digital subtraction angiography (DSA) compared with that of onset. RESULTS Clipping was performed in 30 cases and coil embolization in 8 cases. IAFC was performed an average of 6.6 days after onset. Color gradient mapping demonstrated reduction of the circulation time after IAFC compared with before IAFC on 39 sides, no change on 15 sides, and extension on 3 sides. Average arterial circulation time before IAFC was 2.25 ± 0.57 s and after IAFC was 1.95 ± 0.55 s. IAFC significantly shortened average arterial circulation (P = 0.005). No case developed symptomatic vasospasm after IAFC. CONCLUSION IAFC significantly reduced the cerebral circulation time after aneurysmal SAH and might be effective for the prevention of symptomatic vasospasm.

Fatal subarachnoid hemorrhage caused by Aspergillus arteritis without angiographic abnormalities.

No source of bleeding is detected by angiogram in 15–20% of patients with nonaneurysmal subarachnoid hemorrhage (SAH). This negative angiographic finding might suggest a benign prognosis. We describe a case of fatal SAH caused by Aspergillus arteritis without formation of fusiform dilatation or aneurysms. A 76‐year‐old man with a 2‐month history of progressive visual loss due to pachymeningitis around the optic nerves suffered from SAH in the bilateral sylvian fissures. Repetitive serum galactomannan assay and angiography showed no abnormality. Post mortem examination revealed marked proliferation of Aspergillus in the granulomas of the frontal base dura mater. In addition, major trunks and several branches of the bilateral middle cerebral arteries were invaded by Aspergillus hyphae, which destroyed the walls in the absence of dilatation and aneurysms. Invasive aspergillosis of the CNS often forms a mycotic aneurysm. However, four autopsy cases of nonaneurysmal SAH due to invasive aspergillosis have been reported. The present case is the second autopsy case of Aspergillus arteritis without angiographic abnormality, resulting in fatal SAH. Aggressive and continuous antifungal therapy is absolutely necessary in suspected cases of invasive aspergillosis of the CNS, even if angiography is negative and therapeutic markers of aspergillosis are normal.

Symptomatic Vasospasm in Elderly Patients with Aneurysmal Subarachnoid Hemorrhage: Comparison with Nonelderly Patients

OBJECTIVE To clarify the influence of age on the occurrence of symptomatic vasospasm (SVS), we retrospectively compared 34 elderly (over 70 years) and 71 nonelderly patients with aneurysmal subarachnoid hemorrhage (SAH). METHODS Between 2008 and 2010, at our hospital 105 patients (Hunt and Kosnik grades I-IV) underwent aneurysm surgery within 72 h of the insult. They were divided into four groups based on their age (younger/older than 70 years) and treatment (aneurysmal clipping or coiling). In all patients, we used the same protocol, which included the delivery of intrathecal urokinase and intravenous fasudil chloride; in patients with angiographic evidence of vasospasm, we also injected fasudil chloride intra-arterially. RESULTS Among the elderly patients, 4.3% of those treated by clipping and 9.1% of those treated by coiling experienced SVS; the comparative incidence in younger patients was 6.5% and 4.0%, respectively. The differences were not statistically significant (p = 0.40). The ratio of ventriculo peritoneal (VP) shunts was higher in the elderly patients (p = 0.00007). The incidence of favorable treatment outcomes was significantly lower in elderly patients (p = 0.00004). CONCLUSION Under our treatment protocol, patient age did not affect the incidence of SVS. Our protocol may be effective for the prevention of SVS after aneurysmal SAH regardless of patient age.

Cerebral venous thrombosis with dural arteriovenous fistulas and antiphospholipid syndrome: a case report

Dear Editor, Dural arteriovenous fistulas (DAVF) and antiphospholipid syndrome (APS) are important risk factors for cerebral venous thrombosis (CTV). We describe a young patient presenting with CVT with DAVF and APS. However, the combination of the DAVF and APS has not been reported in patients with CVT. A 38-year-old man visited our outpatient clinic because of abnormal behavior. He had no mental retardation. Two weeks before the visit, he drove into a closed ski slope and crashed his car. When he was found, he had been in the car for 2 days in the ski slope. He was confused and then transferred to a local hospital. Examinations including head CT scan showed no abnormality. His daily behavior initially appeared to be normal after the episode. However, he began to demonstrate abnormal activities such as pouring water onto salad and became unable to do easy arithmetic. He did not complain of headache and fever. He showed no nuchal rigidity on admission. He was disoriented and had bradyphrenia. Mini-mental state examination was 22/30 in which he had severe loss of recent memory. The Rey–Osterrieth figure test revealed severe verbal and visual memory deficits along with inattention. He had no abnormality in cranial nerves. D-dimer was normal and b2GPI-dependent IgG antiphospholipid antibody was 54 U/ml (\3.5 U/ml). Brain MRI revealed abnormal high signals in the bilateral thalamus (Fig. 1). Brain MR venography (MRV) revealed thrombosis in the straight sinus. Digital subtraction angiography showed DAVF from marginal tentorial arteries of bilateral internal carotid arteries, bilateral occipital arteries, tentorial branches of bilateral median meningeal arteries, and right lateral posterior choroidal artery. These DAVF flowed into the vein of Galen, and the blood flow of the DAVF regurgitated into bilateral internal cerebral veins. The vein of Galen and the straight sinus were occluded. The patient was diagnosed as CVT with multiple DAVF and APS. Anticoagulant therapy was started from the day of admission, but he fell into stupor. Three times of transarterial embolisation (TAE) were performed on the DAVF and then the DAVF was surgically resected. The specimen showed arteriovenous shunting between dural arteries and veins with multilayered elastic tissue in venous walls. After the operation, attention and verbal memory on the Rey–Osterrieth figure test remarkably improved. A followup brain MRI showed a decrease in the area of abnormal intensity (Fig. 1). He was discharged without aid. We described a patient with CVT, in which cognitive disorder was a prominent symptom due to venous infarction of the bilateral thalamus by the occlusion of the straight sinus. The patient had DAVF draining into the vein of Galen. Additionally APS was found in our patient. APS is also one of the major risk factors of CVT [1]. DAVF and CVT have been closely related to each other. However, it remains to be elucidated whether DAVF is the Y. Miki (&) M. Tomiyama A. Arai T. Kimura C. Suzuki J. Nunomura M. Baba Department of Neurology, Aomori Prefectural Central Hospital, Higashi Tsukurimichi 2-1-1, Aomori, Japan e-mail: yasuomiki@hotmail.com

Ruptured peripheral aneurysms in a collateral pathway associated with stenosis of a major cerebral artery: Report of two cases.

Background While hemodynamic stress can result in aneurysm formation, it rarely contributes to the development of peripheral aneurysms in collateral pathways. We report two patients with ruptured distal aneurysms in a collateral pathway associated with stenosis of a major cerebral artery. Case Description A 67-year-old man presented with intracerebral hemorrhage in the right frontal lobe. Digital subtraction angiography (DSA) revealed severe stenosis of the right middle cerebral artery and two aneurysms in the collateral pathway of the right anterior cerebral artery. The ruptured aneurysm was trapped and resected; histologically, it was a true saccular aneurysm. The unruptured aneurysm was clipped and the patient was discharged without additional neurological deficits. The second patient was a 73-year-old woman with subarachnoid hemorrhage. DSA revealed three arterial dilations. On the 7th day of hospitalization, one of the aneurysms in a posterior inferior cerebellar artery–anterior inferior cerebellar artery anastomosis that functioned as a collateral pathway in the presence of severe basilar artery stenosis was found to be enlarged. It was treated by selective aneurysmal coil embolization with parent artery preservation. Her postoperative course was uneventful and she was discharged without any neurological deficits. Conclusion We document the successful treatment of two patients with ruptured aneurysms in the peripheral portion of a collateral pathway. We discuss the histology of peripheral aneurysms and present a review of the literature.

Arterial Spin Labeling Imaging of a Giant Aneurysm Leading to Subarachnoid Hemorrhage following Cerebral Infarction

An 83-year-old Japanese man was admitted with dysarthria and right hemiparesis. He had had a large intracranial aneurysm on the left internal carotid artery 5 years before admission and had been followed up under conservative treatment. On admission, diffusion-weighted imaging revealed a hyperintense signal on the left anterior choroidal artery territory. Time-of-flight magnetic resonance angiography demonstrated poor visibility of the middle and anterior cerebral arteries and the inferior giant aneurysm, suggesting distal emboli from aneurysm thrombosis or a reduction of blood outflow due to aneurysm thrombosis. Arterial spin labeling (ASL) signal increased in the giant aneurysm, suggesting blood stagnation within the aneurysmal sac, and decreased in the left hemisphere. We diagnosed cerebral infarction due to aneurysm thrombosis, and started antithrombotic therapy. On day 2, he suddenly died of subarachnoid hemorrhage due to rupturing of the giant aneurysm. When thrombosis occurs in a giant aneurysm, increasing ASL signal within the aneurysm and decreasing ASL signal with poor visibility on magnetic resonance angiography in the same arterial territory may indicate the danger of impending rupture of the giant aneurysm.