Kenichi Murao

Spreading depression induces long-lasting brain protection against infarcted lesion development via BDNF gene-dependent mechanism

Preconditioning the rat brain with spreading depression for 48 h induces potent ischemic tolerance (infarct tolerance) after an interval of 12-15 days, consequently reducing the infarcted lesion size in the acute phase following focal cerebral ischemia. However, persistence of the morphological and functional neuroprotection has not yet been proven. We tested whether tolerance-derived neuroprotection against focal cerebral ischemia persists or merely delays the progress of cerebral infarction. Prolonged spreading depression was induced in mice by placing a depolarized focus with intracerebral microinfusion of KCl for 24 h; after intervals of 3, 6, 9 or 12 days, temporary focal ischemia was imposed. In the analysis of the infarcted lesion volume 24 h after ischemia, groups with 6 or 9 day interval demonstrated significantly smaller lesion volume compared to time-matched vehicle control group (P=0.002). Significant reduction in cerebral infarction was also observed at the chronic phase, namely 14 days after ischemia (33% reduction) (P=0.021) accompanied with less severe neurological deficits (38% reduction) (P=0.020). Using this technique, we also investigated if the mice with targeted disruption of a single BDNF allele (heterozygous BDNF-deficient mice) can gain the same potency of tolerance as the wild mice. In the result on infarcted lesion volumes following temporary focal ischemia, potent tolerance developed in the wild type (35% reduction) (P=0.007) but not in the heterozygous BDNF-deficient mice (<19% reduction) (P=0.155), indicating that BDNF expression level following spreading depression is contributing to infarct tolerance development.

Growth potential and response to multimodality treatment of partially thrombosed large or giant aneurysms in the posterior circulation

OBJECTIVEThis study examined the growth potential and response to multimodality treatment of partially thrombosed large or giant aneurysms in the posterior circulation. METHODSThe 17 aneurysms arose from nonbranching sites of the vertebral artery (VA) in 6 patients and from branching sites in 11 patients (the VA-posteroinferior cerebellar artery [PICA], 3 cases; basilar artery [BA] fenestration, 1 case; BA-superior cerebellar artery [SCA], 5 cases; and BA tip, 2 cases). RESULTSEndovascular trapping was performed in 5 VA aneurysms at nonbranching sites, 2 VA-PICA cases with or without revascularization of the PICA, and 1 BA fenestration case. Endosaccular embolization was performed in 2 BA-SCA aneurysms as the sole treatment or after superficial temporal artery-SCA bypass for a broad-necked lesion. Surgical proximal occlusion (PO) with or without revascularization of the PICA was performed in 2 VA cases. Endovascular treatment failed to prevent growth in 1 VA-PICA case and the broad-necked BA-SCA case. Simple flow alteration by PO of 3 BA aneurysms, with gadolinium enhancement on T1-weighted images, did not prevent growth. Maximum flow reduction by various combinations of bypass (superficial temporal artery-posterior cerebral artery or superficial temporal artery-SCA) and BA PO, aimed at reducing hemodynamic stress on the neck, was tailored to 5 cases, including those refractory to PO; it achieved marked shrinkage in 2 cases and stabilization of the aneurysms in 3 cases. The aneurysms harboring neither gadolinium enhancement nor hyperintensity on fluid-attenuated inversion recovery images showed significantly lower growth potential before treatment and a lesser degree of shrinkage after tailored treatment than the remaining cases (P = 0.03 and P = 0.01, respectively). Overall, marked shrinkage was achieved in 27%, moderate shrinkage in 20%, stabilization in 47%, enlargement in 7%, and favorable outcome in 71%. Maximum flow reduction strategy for BA aneurysms tended to show higher shrinking efficacy than endovascular trapping for VA and BA aneurysms (P = 0.08). CONCLUSIONFor aneurysms at nonbranching sites, endovascular trapping may be effective, although its shrinking efficacy may be moderate. For the most formidable BA aneurysms at branching sites, maximum flow reduction may cause marked shrinkage, even of aggressive lesions.

Pituitary Apoplexy Caused by Ruptured Internal Carotid Artery Aneurysm

Background and Purpose — We report the first case of pituitary apoplexy caused by the rupture of an intracavernous carotid artery aneurysm embedded in a pituitary adenoma. Case Description — A 46-year-old man presented with clinical and CT findings typical of pituitary apoplexy. MRI showed an unusual flow-void protrusion into the intratumoral hematoma, which, however, was not diagnosed as a ruptured aneurysm until severe intraoperative bleeding occurred. Angiography after surgery revealed an intracavernous carotid artery aneurysm. Conclusions — The possible association of adenoma and aneurysmal rupture should be kept in mind when assessing any case of pituitary apoplexy.

Diffusion Tensor Imaging in Chronic Subdural Hematoma: Correlation between Clinical Signs and Fractional Anisotropy in the Pyramidal Tract

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) was introduced as a good technique to evaluate structural abnormalities in the white matter. In this study, we used DTI to examine anisotropic changes of the pyramidal tracts displaced by chronic subdural hematoma (CSDH). MATERIALS AND METHODS: Twenty-six patients with unilateral CSDH underwent DTI before and after surgery. We measured fractional anisotropy (FA) values in pyramidal tracts of bilateral cerebral peduncles and calculated the ratio of the FA value on the lesion side to that on the contralateral side (FA ratio) and compared the ratios with motor weakness. Moreover, the relationships between FA ratios and clinical factors such as age, sex, midline shift, interval from trauma, and hematoma attenuation on CT were evaluated. RESULTS: FA values of pyramidal tracts on the lesion side were significantly lower than those on the contralateral side (0.66 ± 0.07 versus 0.74 ± 0.05, P < .0001). The FA ratio was correlated to the severity of motor weakness (r2 = 0.32, P = .002). FA ratios after surgery improved significantly compared with those before surgery (0.96 ± 0.08 versus 0.89 ± 0.07, P = .0004). Intervals from trauma and the midline shift were significantly associated with decreased FA ratios (P = .0008 and P = .037). CONCLUSIONS: In patients with CSDH, a reversible decrease of FA in the affected pyramidal tract on DTI was correlated to motor weakness. These anisotropic changes were considered to be caused by a reversible distortion of neuron fibers and vasogenic edema due to the hematoma.

Cavernous sinus EEG : A new method for the preoperative evaluation of temporal lobe epilepsy

Summary: Purpose: In presurgical evaluation of temporal lobe epilepsy (TLE), invasive methods are necessary if results of various noninvasive methods are not sufficiently convergent enough to identify the epileptogenic area accurately. To detect the epileptiform discharges originating specifically from the mesial temporal lobe, we applied the cavernous sinus catheterization technique.

Superselective Shunt Occlusion for the Treatment of Cavernous Sinus Dural Arteriovenous Fistulae

BACKGROUND: In treating cavernous sinus dural arteriovenous fistulae (CSdAVFs), transvenous embolization of the whole affected sinus is usually performed, which may result in the disturbance of normal venous drainage or permanent cranial nerve palsy. OBJECTIVE: To describe superselective shunt occlusion of CSdAVFs. METHODS: Between July 2005 and August 2011, we had 20 consecutive cases of CSdAVFs. In 14 cases (70%), we could detect the restricted locus of arteriovenous shunts by 3-dimensional rotational angiography and/or superselective arteriography. After navigating the microcatheter to the shunt segment, consecutive superselective arteriovenography was performed to confirm the location of the microcatheter at the proper position. RESULTS: In 12 of 14 cases (85.7%) in which the shunt was restricted, coiling only in the small venous pouch or compartment, which was just downstream of the shunt point, led to complete disappearance of the shunt without obliterating the entire sinus. No recurrence or permanent cranial nerve palsy was observed during the follow-up period with a mean of 46 months (range, 3-69 months) in 12 cases treated by superselective shunt occlusion. CONCLUSION: This technique, which enables complete extirpation of shunts by small amounts of coils, is a feasible way to treat CSdAVFs with excellent mid- to long-term results. Understanding of the angioarchitecture by 3-dimensional rotational angiography and consecutive superselective arteriovenography was useful. This method should be considered before sinus packing or mere obliteration of dangerous venous outlets. ABBREVIATIONS: AVF, arteriovenous fistula CNP, cranial nerve palsy CS, cavernous sinus CSdAVF, cavernous sinus dural arteriovenous fistula ECA, external carotid artery 3-D RA, 3-dimensional rotational angiography SSSO, superselective shunt occlusion

Endovascular Treatment of Sphenoid Wing Dural Arteriovenous Fistula with Pure Cortical Venous Drainage

Curative endovascular treatment of sphenoid wing dural arteriovenous fistula (dAVF) with pure cortical venous drainage is challenging because of its rarity, lack of accessible dural sinus for transvenous embolization (TVE), and proximity of skull base vital regions. Direct surgery to disconnect venous reflux has been favored. We report the curative endovascular treatment of two sphenoid wing dAVFs with pure cortical venous drainage. One patient revealed complete obliteration of dAVF by a single session of transarterial embolization (TAE). As part of strategic TAE for this complex dAVF, we used a novel approach to create a complete flow-arrest condition in which coils and an occlusion balloon were combined. A liquid agent was then injected across the pathological fistula and into the parent venous apparatus, thereby occluding the lesion. The other patient was treated with percutaneous TVE after TAE was unsuccessful. With a specific strategy and appropriate devices, the microcatheter was successfully introduced through sigmoid sinus, transverse sinus, superior sagittal sinus, and refluxing cortical vein by puncture of the jugular vein. Coils were deployed at the venous side of the fistula, resulting in successful obliteration of the dAVF. Sphenoid wing dAVF with pure cortical venous drainage could be curable by endovascular treatment with proper strategy and instruments when anatomical condition permits.

Efficacy and safety of single versus dual antiplatelet therapy for coiling of unruptured aneurysms.

BACKGROUND Although the efficacy of antiplatelet therapy for coiling of unruptured cerebral aneurysms has been reported, regimens for this therapy are not yet well established. The aim of this retrospective study was to analyze correlations among the modes of antiplatelet use, aneurysmal configuration, coiling methods, and complications to elucidate the optimal antiplatelet therapy for coiling. METHODS The study population comprised 154 patients with unruptured aneurysms who underwent coiling with antiplatelet therapy at our institution between 2001 and 2009. The patients were categorized by mode of antiplatelet therapy (single [n = 64] or dual [n = 90]), neck size (wide [n = 80] or narrow [n = 74]), and technique used (simple [n = 42] or adjunctive [n = 112]). The incidences of hemorrhagic/ischemic complications and abnormalities on postprocedural diffusion-weighted magnetic resonance imaging (DWI) in each group were statistically assessed. RESULTS Hemorrhagic complications occurred in 1 case (1.5%) with single antiplatelet therapy and in 2 cases (2.2%) with dual antiplatelet therapy. Symptomatic ischemic complications occurred in 5 cases (7.8%) with single therapy and in 4 cases (4.4%) with dual therapy. Abnormalities were detected by DWI in 27 cases (42%) with single therapy and in 31 cases (34%) with dual therapy. No significant difference was found between modes of antiplatelet therapy even when the technique used was taken into account. In cases of wide neck, however, there were significant differences in the rate of symptomatic ischemic complications (single, 21.7%; dual, 3.5%; P = .014) and DWI abnormalities (single, 37.8%; dual, 20.9%; P = .048). CONCLUSION Our data suggest that dual antiplatelet therapy may better prevent ischemic complications from coiling for wide-necked aneurysms compared with single antiplatelet therapy.

Infiltrated Embolization of Meningioma with Dilute Cyanoacrylate Glue

We describe the efficacy and technical aspects of infiltrated preoperative embolization of meningioma by penetration of very dilute glue. In this method, a 13% n-butyl-cyanoacrylate (NBCA)-lipiodol mixture is injected extremely slowly from the middle meningeal artery (MMA) in a similar manner to plug and push injection of ethylene vinyl alcohol copolymer mixed with tantalum and dimethyl sulfoxide (Onyx®) after the tortuous side feeders are proximally embolized. The glue is infiltrated into small tumor arteries and extends to inaccessible feeders from deep meningeal arteries. Since 2011, we have used this technique in the embolization of 32 cases preoperatively diagnosed with meningioma. Intratumoral embolization was possible in 30 cases (94%), and a greater than 50% reduction in contrast area of contrast-enhanced T1-weighted MR imaging (T1-WI) was achieved in 18 cases (56%). Two cases achieved complete devascularization, showing a remarkable shrinkage in tumor size after embolization. If excessive reflux of embolization and the resulting migration of glue into normal arteries is achieved, this method provides extremely effective devascularization on surgical extirpation. It might also be applicable to surgically untreatable meningiomas as a semi-radical treatment option.

Multiple cerebral aneurysms in a patient with CREST syndrome.

Systemic sclerosis (SSc) associated with cerebral aneurysm is rare. We describe a patient with multiple cerebral aneurysms with the calcinosis, Raynauds phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia (CREST) variant of SSc. A 61-year-old woman with a 20-year history of CREST syndrome was incidentally found to have four cerebral aneurysms located at the C2, C3 and C5 segments of the right internal carotid artery (ICA) and the C2 segment of the left ICA. The bilateral C2 segment aneurysms were successfully clipped using 2-stage surgery. To date, intracranial aneurysms have been reported in only two other patients with CREST syndrome. We hypothesize that the pathogenesis of the aneurysm is related to CREST syndrome. Elucidating the true incidence of cerebral aneurysms associated with CREST syndrome would help to clarify the relationship between SSc-related autoantibodies and aneurysm formation.