Recanalisation of spontaneously occluded vertebral artery dissection after subarachnoid haemorrhage.

Spontaneous occlusion is a rare manifestation of ruptured vertebral artery dissection (VAD). Its natural history and treatment strategy have yet to be established due to its rarity. Here, we report five lesions involving spontaneous occlusion of VAD after subarachnoid haemorrhage, among which three lesions showed recanalisation. Based on our experience and previous reports, spontaneous occlusion of ruptured VAD can be classified into two groups-one group with occlusion in the acute stage with a high incidence of recanalisation and another group with occlusion in the chronic stage with a relatively low incidence of recanalisation. The underlying mechanism is likely different in each group, and treatment strategies should also be tailored depending on the pathophysiology.

A multi-center, prospective study on the progression rate of asymptomatic ventriculomegaly with features of idiopathic normal pressure hydrocephalus on magnetic resonance imaging to idiopathic normal pressure hydrocephalus.

INTRODUCTION: Our previous community-based study demonstrated that some individuals with AVIM [asymptomatic ventriculomegaly with features of idiopathic normal pressure hydrocephalus (iNPH) on magnetic resonance imaging (MRI)] progressed to iNPH in several years. In this hospital-based study, we investigated the progression rate from AVIM to iNPH and its possible predictors. METHODS: We conducted a prospective study of participants with AVIM from several medical institutions/hospitals in Japan. AVIM is defined as "asymptomatic ventriculomegaly with features of iNPH on MRI"; in the present study, asymptomatic was defined as "0 (no symptoms) or 1 (presence of only subjective, but not objective, symptoms) on the iNPH Grading Scale (iNPH-GS)." We also measured possible predicting factors for AVIM-to-iNPH progression, including age, sex, body weight, blood pressure, diabetes mellitus, dyslipidemia, history of mental disease/head injury/sinusitis/smoking/alcohol-intake, Evans index, and the presence of DESH (disproportionately enlarged subarachnoid-space hydrocephalus) findings on brain MRI, and analyzed these potential predictive values. RESULTS: In 2012, 93 participants with AVIM were registered and enrolled in the study. Of these, 52 participants were able to be tracked for three years (until 2015). Of the 52 participants, 27 (52%) developed iNPH during the follow-up period (11 definite, 6 probable, and 10 possible iNPH), whereas 25 participants remained asymptomatic in 2015. Among the possible predictive factors examined, the baseline scores of iNPH-GS predicted the AVIM-to-iNPH progression. CONCLUSIONS: The multicenter prospective study demonstrated that the progression rate from AVIM to iNPH was ~17% per year, and the baseline scores of iNPH-GS predicted the AVIM-to-iNPH progression.

Influence of photon scattering and attenuation on ROI analysis in brain perfusion single-photon emission tomographic imaging of normal subjects.

OBJECTIVE: The aim of this study was to evaluate the effect of scatter and attenuation correction in region of interest (ROI) analysis in brain perfusion single-photon emission tomography (SPECT) and to assess the influence of selecting the reference area on semi-quantification. METHODS: Ten normal subjects were enrolled and injected with 123I-iodoamphetamine to undergo simultaneous emission and transmission scanning for scatter and attenuation correction. We reconstructed three SPECT images from common projection data of each subject: with scatter correction and non-uniform attenuation correction, with scatter correction and uniform attenuation correction, and with uniform attenuation correction applied to data without scatter correction. A program for automated ROI drawing was used to set ROIs on various regions in brain images. Regional count ratios were compared in images with different correction procedures by using three different reference areas. RESULTS: The effect of the combination of scatter and attenuation correction was marked in the precentral, temporal, posterior, hippocampus and especially in the cerebellum. In contrast, it was not appreciable in the central and parietal areas. When using the cerebellar ROI as the reference, the count ratio varied widely depending on the correction procedures. On the other hand, the whole brain reference offered the least variation in the count ratio. CONCLUSIONS: The influence of photon scattering and attenuation was dependent on regions. Since the count in the cerebellar ROI is greatly affected by photon scattering and attenuation, nonuniform attenuation correction combined with scatter correction deserves consideration when using the cerebellar ROI as the reference.

Intra-arterial CT-angiography for cerebral arteriovenous malformation--initial experiences for treatment planning of radiosurgery.

PURPOSE: To clarify the feasibility and effectiveness of intra-arterial CT angiography (IACTA) for treatment planning of arteriovenous malformation radiosurgery. METHODS AND MATERIALS: A CT scanner installed in an angiographic examination room was used. Helical IACTA was performed in 22 patients during continuous intra-arterial infusion of contrast medium via the internal carotid or vertebral artery, and dynamic IACTA was performed in 20 of these patients with reconstruction at 0.2-s intervals. The dynamic IACTA was repeated for each 3- or 5-mm increment to encompass the nidus. Subtractions were performed in postembolization cases. A retrospective review of IACTA was performed to assess the effectiveness of dynamic scans. RESULTS: No complications related to the angiographic procedure or CT imaging were detected. High contrast enhancement was obtained for both helical and dynamic IACTA. In 18 of the 20 cases (90%), draining veins were separated from the nidus by using the enhancement patterns, and in 13 cases (65%), feeding arteries were separated. CONCLUSION: Dynamic IACTA added important information for target-volume determinations. Conventional CT and MRI could be omitted from the protocol, and the period that patients wore the frame was substantially shortened. We conclude that IACTA is a practical and useful method for radiosurgical treatment planning of arteriovenous malformations.

Cortical blindness during coil embolization of an unruptured intracranial aneurysm--case report.

A 62-year-old woman suffered transient cortical blindness during coil embolization for a saccular aneurysm in the posterior circulation, with cerebral angiography using non-ionic contrast material. Just before completion of the procedure, the patient showed abrupt onset of restlessness and blindness. At this point 150 ml of contrast material had been injected into the left vertebral artery. Immediate computed tomography showed persistence of contrast medium in the bilateral occipital lobes and part of the left frontal lobe. Repeat angiography showed no evidence of embolism. Single photon emission computed tomography obtained the next day showed decreased perfusion in the bilateral occipital lobes. Magnetic resonance imaging on the third day showed multiple lesions in the bilateral occipital lobes. Her vision was restored gradually. Transient cortical blindness may be associated with osmotic disruption of the blood-brain barrier in the bilateral occipital lobes. Endovascular neurosurgeons must be aware of this rare complication.

Perimedullary arteriovenous fistula at the craniocervical junction - case report - .

Perimedullary arteriovenous fistulas (AVFs) at the craniocervical junction are uncommon, and are often fed by the anterior spinal artery, with only a few cases fed by the intradural vertebral artery (VA). A 55-year-old man presented with a case of perimedullary AVF fed by the VA at the craniocervical junction manifesting as subarachnoid hemorrhage. Left vertebral angiography demonstrated an AVF supplied by branches from the VA. Three-dimensional computed tomography angiography (3D-CTA) revealed that the feeding arteries originated from the VA at the intradural position. Two feeding arteries were coagulated and dissected, followed by coagulation of a small feeder. The draining veins became discolored and shrank. 3D-CTA performed 2 months after the operation revealed disappearance of the AVF. Open surgery was successfully performed for the almost perimedullary AVF at the craniocervical junction, and is considered to be preferable for the treatment of this disease.

Long-term surgical outcome and biological prognostic factors in patients with skull base meningiomas.

OBJECT: Although gross-total resection (GTR) is a preferable treatment for skull base meningiomas, subtotal resection (STR) with or without radiation therapy can be considered as an alternative treatment for patients at considerable surgical risk. The long-term prognosis of such patients might be related to the biological activity of the tumor. This study examined predictors of progression-free survival (PFS) and sought to determine the optimal treatment strategies, focusing on the pathobiological findings of skull base meningiomas. METHODS: This study included 281 patients with skull base meningiomas (mean follow-up period 88.4 months). Risk factors for tumor progression were examined using a multivariate analysis. The PFS and overall survival (OS) rates were evaluated using the Kaplan-Meier method. The functional outcomes of the patients were measured using the Karnofsky Performance Scale (KPS). RESULTS: The 10-year PFS and OS rates were 66.4% and 97.4%, respectively. Overall, 83.3% of patients achieved a favorable outcome, that is, an improved or unchanged KPS score. The extent of resection, additional radiotherapy, histological grade, MIB-1 index, and p53-positive rate were significantly associated with PFS. The PFS of patients undergoing STR without radiation therapy was significantly shorter than that of either those undergoing STR with radiation therapy or GTR, while no statistical difference was observed between the latter 2 groups. Among the patients undergoing STR with pathobiological risk factors (histological grade, MIB-1 index, and p53-positive rate), the PFS of the patients who received radiation therapy was better than that of those who did not receive radiation therapy. Among the patients undergoing STR without such risk factors, the PFS was not significantly different between patients who received radiation therapy and those who did not. CONCLUSIONS: For patients with skull base meningiomas, a GTR is desirable and additional radiation therapy after STR may contribute to a longer PFS. Additional radiation therapy should be recommended, especially for patients with pathobiological risk factors, but not necessarily for those without such risks.

Long-term follow up of antegrade recanalization of vertebral artery dissecting aneurysm after internal trapping: case report.

A 34-year-old female presented with subarachnoid hemorrhage caused by the rupture of a right vertebral artery (VA) dissecting aneurysm. The affected site, including the aneurysm and parent artery, was successfully occluded with detachable coils. Follow-up angiography performed 28 days after the endovascular treatment revealed recanalization of the parent artery. We decided to treat the patient conservatively without further intervention because the aneurysm had been completely occluded. Magnetic resonance imaging showed a normal VA configuration with a minor irregularity of the affected wall at 6 years after onset. Rebleeding tends to occur during the acute stage because spontaneous healing of the dissecting vascular wall typically occurs within one month after onset. Our case suggests that additional intervention is unnecessary during the chronic stage once the aneurysm has been occluded and no further signs of the development of VA dissection are found.

ABC Surgical Risk Scale for skull base meningioma: a new scoring system for predicting the extent of tumor removal and neurological outcome. Clinical article.

OBJECT: Surgery for skull base meningiomas (SBMs) can lead to complications because these lesions are difficult to approach and can involve cranial nerves and arteries. The authors propose a scoring system to evaluate the relative risks and benefits of surgical treatment of SBMs. METHODS: The authors used a 2-step process to construct their scale. First, they derived significant predictive variables from retrospective data on 132 SBM cases treated surgically (primary surgeries only) between May 2000 and December 2005. Next, they validated the predictive accuracy of their scoring system in 60 consecutive cases treated surgically between January 1995 and April 2000, including both primary and repeated surgeries. Finally, they investigated the effect of the surgery on the patients' preoperative symptoms for consecutive cases treated surgically between January 1995 and December 2005, including both primary surgeries and retreatments. RESULTS: Five items that predicted surgical risk were identified: 1) tumor attachment size; 2) arterial involvement; 3) brainstem contact; 4) central cavity location; and 5) cranial nerve group involvement. The authors named their scoring system the ABC Surgical Risk Scale, after the initial letters of these items. Each factor was assigned a score of 0-2 points, and an additional point was added for previous surgical treatment or for radiation, giving a possible total score of 12 points. On average, the scoring system allocated 2 points for gross-total resections, 6.1 points for near-total resections, and 9 points for subtotal resections, with significant differences between groups. For cases scoring >or= 8 points, the percentage of cases showing neurological deterioration postoperatively exceeded the percentage showing improvement. CONCLUSIONS: The authors conclude that this scoring system can be used to predict the extent of tumor removal and that the scores reflect the surgical risk.

Radiosurgical treatment planning for intracranial AVM based on images generated by principal component analysis--a simulation study.

BACKGROUND: One of the most important factors in stereotactic radiosurgery (SRS) for intracranial arteriovenous malformation (AVM) is to determine accurate target delineation of the nidus. However, since intracranial AVMs are complicated in structure, it is often difficult to clearly determine the target delineation. PURPOSE: To investigate the usefulness of principal component analysis (PCA) on intra-arterial contrast enhanced dynamic CT (IADCT) images as a tool for delineating accurate target volumes for stereotactic radiosurgery of AVMs. MATERIALS AND METHODS: IADCT and intravenous contrast-enhanced CT (IVCT) were used to examine 4 randomly selected cases of AVM. PCA images were generated from the IADCT data. The first component images were considered feeding artery predominant, the second component images were considered draining vein predominant, and the third component images were considered background. Target delineations were first carried out from IVCT, and then again while referring to the first and second components of the PCA images. Dose calculation simulations for radiosurgical treatment plans with IVCT and PCA images were performed. Dose volume histograms of the vein areas as well as the target volumes were compared. RESULTS: In all cases, the calculated target volumes based on IVCT images were larger than those based on PCA images, and the irradiation doses for the vein areas were reduced. CONCLUSION: In this study, we simulated radiosurgical treatment planning for intracranial AVM based on PCA images. By using PCA images, the irradiation doses for the vein areas were substantially reduced.

The validity of intraoperative angiography for the treatment of spinal arteriovenous fistula.

STUDY DESIGN: Retrospective study of patients with spinal arteriovenous fistula (AVF) who underwent surgical treatment. OBJECTIVE: To evaluate the validity of the intraoperative angiography (IA) for the surgical treatment of spinal AVF. SUMMARY OF BACKGROUND DATA: Owing to the development of interventional techniques, endovascular embolization has become the treatment of choice for AVF, but it is not applicable for every spinal AVF owing to anatomic complexity of the spinal cord vessels. To get effective occlusion of the AVF, IA has been routinely used in the management of cerebral vascular diseases, but report of its use for spinal AVF is rare. METHODS: Since 2004, 4 consecutive cases of spinal AVF (3 males and 1 female, 3 thoracic, and 1 thoracolumbar) were involved in this study. The mean age at the time of operation was 62.3 years (range from 48 to 76 y). Types of AVFs and surgical techniques were reviewed retrospectively and the outcomes were assessed using the Japanese Orthopedic Association scoring system. RESULTS: AVFs in 3 patients were diagnosed as the dural type and that in the remaining patient as the perimedullary type; all feeding arteries were derived from the ninth to 10th intercostal arteries. Preoperative angiography demonstrated that the feeding arteries in 2 patients with a dural AVF were the branches of Adamkiewicz artery and in another dural AVF case, the Adamkiewicz artery could not be determined, therefore, endovascular embolization was not feasible. Including a patient with perimedullary AVF, a microsurgical clipping combined with IA was selected as the treatment. Complete occlusion of the fistula was achieved in all cases, the mean preoperative Japanese Orthopedic Association score of 4.5 improved to 6 at the final follow-up, and no perioperative complications were observed during the follow-up period. CONCLUSIONS: The favorable clinical results in our spinal AVF cases confirmed that IA ensures safe and accurate occlusion of the fistula. This technique provides satisfactory surgical results for spinal AVFs.

Motor-related intracortical steal phenomenon detected by multichannel functional near-infrared spectroscopy imaging.

BACKGROUND: Patients with severe cerebral ischemia may lose autoregulation to increase cerebral blood flow following neural activity. Although the steal phenomenon under conventional cerebral blood flow study has been known as a high-risk factor for stroke, the cerebral oxygen hemodynamics in ischemic patients during functional activation has not been thoroughly investigated. In this study, we present rare cases with intracortical steal phenomenon during motor tasks detected by multichannel functional near-infrared spectroscopy before and after surgery. METHODS: The relative concentration change of oxygenated, deoxygenated and total hemoglobin in and around the primary sensorimotor cortex during contralateral hand grasping was investigated in 11 patients with severe internal carotid artery stenosis. RESULTS: In 3 patients, the concentration of total hemoglobin around the primary sensorimotor cortex significantly decreased in response to motor stimulation and returned to baseline soon after termination of the motor task. This phenomenon partially disappeared postoperatively in all patients who underwent surgery. The remaining 8 patients showed no signs of total hemoglobin decrease in and around the sensorimotor cortex. In 9 patients, lack of decrease in deoxygenated hemoglobin in the center of the primary motor cortex during the motor task was observed and 3 of them showed significant increase in deoxygenated hemoglobin. CONCLUSIONS: We have demonstrated that in some patients with severe ischemia, an abnormal motor-related steal phenomenon can be observed. This phenomenon can be modulated by surgical intervention and might imply the severity of ischemia.