Yasuyuki Kaku

Multiple peripheral middle cerebral artery aneurysms associated with Behcet's disease.

SummaryWe report a 19-year-old woman with Behcet’s disease who suffered a subarachnoid hemorrhage and had bilateral peripheral middle cerebral artery aneurysms. After steroid therapy for 3 days, the smaller aneurysm disappeared. The larger aneurysm was excised and the artery reconstructed using a superficial temporary artery graft. Histological examination showed vasculitis restricted to the wall of the aneurysm. This is the first report of arterial reconstruction for an aneurysm associated with Behcet’s disease. Steroid therapy before the operation may facilitate repair of the arterial wall.

The Leptomeningeal Ivy Sign on Fluid-Attenuated Inversion Recovery Images in Moyamoya Disease: Positron Emission Tomography Study

Background: The ivy sign is sometimes seen on fluid-attenuated inversion recovery (FLAIR) images in moyamoya disease (MMD). In recent studies using single-photon emission computed tomography, ivy sign proliferation correlated with decreases in cerebrovascular reserve. However, a decreased vascular reserve is not concrete. The purpose of this study was to evaluate the correlation between ivy sign proliferation and the findings of 15O gas positron emission tomography (PET). Methods: In 19 MMD patients (12 women, age 31-69 years) with ischemic symptoms, FLAIR magnetic resonance imaging and 15O gas PET were performed. We classified the middle cerebral artery (MCA) territory into 2 regions in each hemisphere, and the degree of the ivy sign (ivy sign score) in each region was classified into 3 grades (0-2), where grade 0 indicated an absence of the ivy sign, grade 1 indicated that the ivy sign was seen on less than half of the cortical surface in each region, and grade 2 indicated that the ivy sign was seen on more than half of the cortical surface. We examined the relationship among the ivy sign score, the severity of ischemic symptoms and PET parameters in 76 MCA regions of 19 patients. Results: Ivy sign scores of the regions were 0 (n = 19), 1 (n = 40), and 2 (n = 17). Total ivy sign score of a hemisphere increased as clinical symptoms became more severe. Cerebral blood flow (CBF) values were lower, cerebral blood volume (CBV) values were higher, and CBF/CBV values were lower than those of controls as symptoms became severe (p < 0.05). CBF and CBF/CBV values decreased and CBV values increased as the ivy sign score increased, and were significantly higher and lower, respectively, than control values (p < 0.05). No significant differences in cerebral metabolic rate of oxygen and oxygen extraction fraction were found between the 3 ivy sign scores. A positive correlation was found between ivy sign score and increases in CBV (p < 0.01), and a more obvious negative correlation was found between ivy sign score and decreases in CBF/CBV (p < 0.001). Conclusions: We evaluated the correlation between ivy sign proliferation and the findings of 15O gas PET. We suggested that ivy sign proliferation was associated with both dilated pial vasculature and the slow flow of developed leptomeningeal collaterals in patients with MMD.

Evaluation of Intracranial Arteriovenous Malformations With Four-Dimensional Arterial-Spin Labeling-Based 3-T Magnetic Resonance Angiography.

Objective We aimed to assess the usefulness of 3-T 4-dimensional (4D) arterial spin-labeling (ASL)–based magnetic resonance angiography (MRA) with color-coded time-of-arrival (TOA) maps for the evaluation of cerebral arteriovenous malformations (AVMs). Methods Our study included 6 patients with cerebral AVMs. They underwent 4D-ASL MRA at 3T and digital subtraction angiography. A pseudocontinuous arterial spin labeling protocol with look-locker sampling was used for spin labeling. Two independent readers reviewed the 4D-ASL MRA images with color-coded TOA maps for the nidus size, arterial feeders, and venous drainage. Two other readers consensually reviewed the digital subtraction angiography images. Results The cerebral AVMs were demonstrated on all 4D-ASL MRA images. In 5 high-flow AVMs, the color-coded TOA maps were especially useful for identifying the feeder/drainer. Intermodality agreement was excellent for the nidus size (&kgr; = 1.0), very good for arterial feeders (&kgr; = 0.88), and good for venous drainage (&kgr; = 0.80). Conclusions The 4D-ASL 3-T MRA with color-coded TOA maps is useful for assessing the gross angiographic characteristics of intracranial AVMs.

Prolonged Mean Transit Time Detected by Dynamic Susceptibility Contrast Magnetic Resonance Imaging Predicts Cerebrovascular Reserve Impairment in Patients with Moyamoya Disease

Background: Evaluating cerebrovascular reserve (CVR) is important for patients with moyamoya disease (MMD). 123I-iodoamphetamine single-photon emission CT (SPECT) with acetazolamide (ACZ) challenge is widely carried out, but using ACZ becomes problematic owing to its off-label use and its adverse effects. Here, we report the efficacy of dynamic susceptibility contrast MRI (DSC-MRI) for the evaluation of CVR in MMD patients. Methods: All 33 MMD patients underwent both SPECT and DSC-MRI at an interval of <10 days from each other (mean age 38.3 years). The region of interest (ROI) was the anterior cerebral artery (ACA) territory, middle cerebral artery (MCA) territory, basal ganglia and cerebellum hemisphere for cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) images. The ratios of the ROIs to the ipsilateral cerebellum were calculated for each parameter and evaluated. The CVR was calculated using images acquired by SPECT before and after ACZ administration. The ratios of DSC-MRI parameters and CVR were compared and evaluated for each ROI. Results: The MTT of the ACA and MCA territories significantly correlated with CVR (p < 0.0001). However, CBF and CBV had no correlation with CVR. The MTT ratio had a threshold of 1.966, with a sensitivity of 68.4% and a specificity of 91.5% for predicting decreased CVR (<10%). Conclusion: MTT had a negative correlation with CVR. DSC-MRI is easy, safe and useful for detecting decreased CVR and can be used as a standard examination in MMD patients care.

Granulocyte Colony-Stimulating Factor Enhances the Angiogenetic Effect of Indirect Bypass Surgery for Chronic Cerebral Hypoperfusion in a Rat Model

BACKGROUND:Granulocyte colony-stimulating factor (G-CSF) mobilizes hematopoietic bone marrow cells into systemic circulation and has been used clinically to treat chemotherapy-induced neutropenia. Recently, G-CSF was shown to have neuroprotective and angiogenetic effects in acute cerebral infarction. OBJECTIVE:To evaluate the effects of G-CSF for angiogenesis after indirect bypass surgery. METHODS:Chronic cerebral hypoperfusions were induced in male Wistar rats by permanent bilateral internal carotid artery occlusion (BICAO). After BICAO, unilateral indirect bypass and encephalogaleosynangiosis (EGS) were performed, and human recombinant G-CSF (10 μg/kg) or saline was injected intramuscularly for 5 consecutive days. We measured regional cerebral blood flow (rCBF) by laser Doppler flowmetry and performed immunohistochemical analysis 21 days after BICAO. RESULTS:BICAO decreased rCBF to 62.52% ± 5.8% of control (P < .01). The rCBF increased significantly 21 days after BICAO in all treatment groups (n = 10; P < .05) except the G-E- group. The rCBF increase observed in the G+E+ group was significantly higher than that observed in other groups. Both G-CSF and EGS treatments significantly increased the number of small vessels (P < .01), and G-CSF and EGS showed additive effect in increasing the number of small vessels. CONCLUSION:Combined use of G-CSF and indirect bypass surgery induces an increase in rCBF and angiogenesis under conditions of cerebral chronic hypoperfusion. This is the first report to demonstrate that G-CSF can enhance angiogenesis induced by indirect bypass surgery, and that this combined therapy is a safe and easy method of treatment.

A 6-Fr guiding catheter (Slim Guide(®)) for use with multiple microdevices.

Background: We developed a new 6-Fr guiding catheter (Slim Guide®) that features a large lumen (0.072 inch) for performing advanced techniques as are required in patients with wide-necked aneurysms whose treatment with a single microcatheter is difficult. Methods: The Slim Guide was used to address 30 saccular and 20 dissecting aneurysms. All 50 patients presented with subarachnoid hemorrhage. To perform the advanced techniques we used SL-10® or Excel 14® and Hyperform® balloon microcatheters. Results: Of the 30 patients with saccular aneurysms, 20 were treated with the double microcatheter- and the other 10 with the balloon assist technique. All 20 patients with dissecting aneurysms were treated with the double microcatheter technique. We encountered slight interference during the treatment of one saccular aneurysm with the balloon assist technique using the Slim Guide guiding catheter; another patient with a saccular aneurysm treated with the balloon assist technique suffered a minor transient ischemic complication. Conclusions: With the Slim Guide, the risks inherent in the application of advanced techniques may be decreased. Its use facilitates the coil embolization of aneurysms that pose treatment challenges.

High prevalence of small vessel disease long after cranial irradiation

Accelerated atherosclerosis of intra- or extracranial large arteries is a major cause of radiation-induced strokes. Recent development of MRI techniques has enabled detection of another important vasculopathy: microinfarcts or microbleeds after cranial irradiation. The purpose of this study was to investigate the incidence and characteristics of small vessel disease after cranial irradiation. MR images and clinical records of 102 outpatients who had undergone cranial irradiation to brain tumors were retrospectively reviewed. Only those who had undergone T1WI, T2WI, FLAIR, and T2∗WI during follow-up were included. Small vessel disease including small subcortical infracts, microbleeds, and volume of white matter lesions were assessed on the latest MR images of each patient. Ischemic or hemorrhagic stroke during the follow-up period was also reviewed. Twelve patients (mean age at the latest MRI, 38.5years; 8men) were assessed. The total radiation dose was 52.3±9.7Gy in these patients, 9 of whom received whole brain irradiation. Small subcortical infarcts (mean 2.3) were detected in 8 patients, microbleeds (mean 19.4) were detected in 11, and white matter lesion volume was 38.3±11.6ml. During the follow-up period of 19.8±9.7years, 5 patients experienced stroke (4 lacunar, 1 hemorrhagic). These strokes occurred as long as a median 21.9 (range, 10.4-30.2) years after cranial irradiation. In conclusion, small vessel disease is not a rare complication after cranial irradiation, even in young patients. Patients after cranial irradiation should be followed up with MR imaging including a hemosiderin-sensitive sequence.

A 6-Fr Guiding Catheter (Slim Guide®) for Use with Multiple Microdevices: An Experimental Study

A modified technique is required in patients with wide-necked aneurysms whose treatment by the single microcatheter technique is difficult. We developed a 6-Fr guiding catheter (Slim Guide®) that features a large lumen (0.072 inch) for performing the modified technique. To evaluate the usefulness of Slim Guide® we carried out experiments using three types of 6-Fr guiding catheter. In experiment 1, the shaft hardness and kink resistance were compared among three different guiding catheters (Slim Guide®, Launcher®, Envoy®). In experiment 2, we inserted a microballoon catheter and a microcatheter into the three different guiding catheters and recorded the maximal infusion pressure. In experiment 3, we inserted 13 different types of microdevices into the three different guiding catheters and evaluated the resistance of the microdevices. Although the shaft of the Slim Guide® was softer than that of the other two guiding catheters, its kink resistance was comparable. The maximal infusion pressure was significantly lower than with Launcher® or Envoy® catheters. Furthermore, with Slim Guide®, in 136 of 143 microdevice combinations examined (95.1%) there was no resistance; this was true for 125 (87.4%) and 116 (81.1%) combinations using the Launcher® - and the Envoy® guiding catheters, respectively. There was a significant difference between Slim Guide® and the other two guiding catheters with respect to their accommodation of double microsystems (p<0.05). Although the inner diameter of Slim Guide® is slightly larger than of the other two guiding catheters, it significantly increased the combination of microdevices that could be used for the coil embolization of difficult aneurysms.

Remote lesions of synchronous sacral and cervical dural arteriovenous fistulas: a case report

BACKGROUND Spinal dural arteriovenous fistula (DAVF) is a rare disease, and multiple concurrent lesions are extremely rare. Such multiple spinal DAVFs have similar outflow routes at neighboring levels. However, there have been no reported cases of remote lesions of multiple spinal DAVFs. The authors herein report a case of double synchronous cervical and sacral DAVFs. CASE DESCRIPTION A 56-year-old man with no previous history of disease presented with progressive myelopathy, and spinal magnetic resonance imaging showed extensive edema of the spinal cord from the conus to T7. The initial angiography incidentally revealed a C1 DAVF, but the sacral DAVF was not diagnosed. The C1 DAVF was treated surgically, because of the risk of subarachnoid hemorrhage. A second angiography was performed 2 months after the first surgery because of high clinical suspicion, and the sacral DAVF was diagnosed at that time. The sacral DAVF was treated surgically, and the symptoms gradually resolved within 6 months after surgery. CONCLUSIONS Spinal DAVF is a rare disease, but clinicians should be aware of the possibility of the concurrence of multiple spinal fistulas located at different levels in the same patient.

Subarachnoid Hemorrhage Because of Distal Superior Cerebellar Artery Dissection in Neurofibromatosis Type 1

BACKGROUND Neurofibromatosis type 1 (NF1) is a rare disease with an incidence of 1 in every 3000 births. Numerous studies have focused on the main function of NF1 as a tumor suppressor, whereas few have examined the cerebrovascular abnormalities observed in patients with NF1. It is worth noting that intracranial aneurysms are uncommon in this condition. CASE DESCRIPTION We report a case of NF1 with a dissection of the distal segment of the superior cerebellar artery. A 36-year-old woman presented with a distal superior cerebellar artery (SCA) dissection causing subarachnoid hemorrhage. Subsequently, because of the rich collateral blood flow distal to the dissection, N-butyl cyanoacrylate (NBCA) glue embolization was unsuccessful. Therefore, direct trapping of the artery was necessary. The patient was discharged after an uneventful postoperative period, and has remained without complications. CONCLUSIONS In the treatment of subarachnoid hemorrhage because of a distal SCA dissection in patients with NF1, NBCA glue embolization may be a safer option than microsurgery or coil embolization, in the acute phase, considering the possible vulnerability of the vessel wall, accessibility, morphology of the lesions, and the risk of developing unpredictable infarcts in the case of parent artery occlusion. However, regular reevaluation of the blood flow is necessary to monitor recurrence, given the rich collateral circulation.