Kazumichi Yoshida

Independent predictors for recurrence of chronic subdural hematoma: a review of 343 consecutive surgical cases.

OBJECTIVE Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a substantial recurrence rate. We focused on determining independent predictors associated with the recurrence of CSDH. METHODS We retrospectively reviewed 343 consecutive surgical cases of CSDH. Univariate and multivariate analyses were performed to describe the relationships between recurrence of CSDH and factors such as sex, age, hypertension, diabetes mellitus, heart disease, cerebrovascular disease, atrial fibrillation, antiplatelet or anticoagulant therapy, and bilateral CSDH. RESULTS Sixty-one patients experienced a recurrence of CSDH. Univariate and multivariate analyses found that bilateral CSDH was an independent risk factor for the recurrence of CSDH. Although antiplatelet and anticoagulant therapy had no significant effect on recurrence of CSDH, the time interval between the injury and the first operation for patients with antiplatelet and/or anticoagulant therapy was shorter than that for patients without it (29.9 versus 44.2 days). CONCLUSION Bilateral CSDH was an independent predictor for the recurrence of CSDH. Antiplatelet or anticoagulant drugs might facilitate the growth of CSDH. These results may help to identify patients at high risk for the recurrence of CSDH.

Characterization of Carotid Atherosclerosis and Detection of Soft Plaque with Use of Black-Blood MR Imaging

BACKGROUND AND PURPOSE: In the treatment of carotid atherosclerosis, the rate of stenosis and characteristics of plaque should be assessed to diagnose vulnerable plaques that increase the risk for cerebral infarction. We performed carotid black-blood (BB) MR imaging to diagnose plaque components and assess plaque hardness based on MR signals. MATERIALS AND METHODS: Three images of BB-MR imaging per plaque were obtained from 70 consecutive patients who underwent carotid endarterectomy (CEA) to generate T1- and T2-weighted images. To evaluate the relative signal intensity (rSI) of plaque components and the relationship between histologic findings and symptoms, we prepared sections at 2-mm intervals from 34 intact plaques. We then calculated the relative overall signal intensity (roSI) of 70 plaques to assess the relationship between MR signal intensity and plaque hardness and symptoms. RESULTS: The characteristics of rSI values on T1- and T2-weighted images of fibrous cap (FC), fibrosis, calcification, myxomatous tissue, lipid core (LC) with intraplaque hemorrhage (IPH), and LC without IPH differed. Symptomatic plaques were associated with FC disruption (P < .001) and LC with IPH (P < .05). The roSI on T1-weighted images was significantly higher for soft than nonsoft plaques. When the roSI cutoff value was set at 1.25 (mean of the roSI), soft plaques were diagnosed with 79.4% sensitivity and 84.4% specificity. The roSI was also significantly higher for symptomatic than for asymptomatic plaques. Soft and nonsoft plaques as well as symptomatic and asymptomatic plaques did not significantly differ on T2-weighted images. CONCLUSION: BB-MR imaging can diagnose plaque components and predict plaque hardness. This procedure provides useful information for planning therapeutic strategies of carotid atherosclerosis.

Characterization of atherosclerotic plaque of carotid arteries with histopathological correlation: Vascular wall MR imaging vs. color Doppler ultrasonography (US)†

To investigate whether the vessel wall MRI of carotid arteries would differentiate at‐risk soft plaque from solid fibrous plaque by identifying liquid components more accurately than color Doppler ultrasonography (US).

Association Between Carotid Atherosclerosis Plaque With High Signal Intensity on T1-Weighted Imaging and Subsequent Ipsilateral Ischemic Events

BACKGROUND:An association between magnetic resonance imaging detection of intraplaque hemorrhage and the risk of cerebral ischemic events has been described. However, few studies have followed patients with intraplaque hemorrhage. OBJECTIVE:We used 3-dimensional gradient-echo black-blood T1-weighted imaging (screening BB [S-BB]) as a magnetic resonance imaging sequence to evaluate acute cerebrovascular stroke. The association between S-BB high signal plaques and the risk of subsequent ipsilateral ischemic events was investigated. METHODS:A total of 928 consecutive patients hospitalized for a stroke or transient ischemic attack according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification were evaluated. Recurrence was retrospectively evaluated in S-BB–positive patients and patients with severe stenosis (SS) (≥70%) by magnetic resonance angiography. Based on clinical and imaging findings, recurrence was defined as a carotid artery stroke or transient ischemic attack that developed after hospital discharge as an initial event. RESULTS:Sixty-six patients were S-BB positive and 62 patients had severe stenosis (S-BB positive with SS, 32 patients; S-BB negative with SS, 30 patients; S-BB positive without SS, 34 patients). During a mean follow-up period of 9.1 months, 7 S-BB–positive patients with SS (18.7%) and 1 S-BB-negative patient with SS (3%) had a recurrent event (P = .051). In the S-BB–positive group, in 34 patients without SS, the recurrence rate was 14.7% (5/34); the difference in the recurrence rate between S-BB–positive group with and without SS was not significant (P = .34). CONCLUSION:Patients with carotid artery lesions and intraplaque hemorrhage tend to be at higher risk of a subsequent ipsilateral ischemic event. Risk evaluation of carotid artery disease should include plaque characteristics.

Intrasellar meningioma: case report and review of the literature.

BACKGROUND Intrasellar meningioma is a rare clinical entity, and surgical resection may be difficult when it is hypervascularized. METHODS A case of subdiaphragmatic hypervascular intrasellar meningioma with attachment to the dura of the anterior wall of the sella turcica is described. Literature review of 18 cases with operatively confirmed intrasellar meningioma discloses unexpected intraoperative bleeding and relatively low resectability of the tumor are also described. RESULTS We used preoperative endovascular embolization of feeding arteries, and resected a hypervascular intrasellar meningioma by a combined transsphenoidal-transcranial approach safely and without massive bleeding. CONCLUSIONS Preoperative endovascular embolization of feeding arteries and combined transsphenoidal-transcranial approach are useful for the surgical resection of hypervascular intrasellar meningiomas.

Impact of posterior cerebral artery involvement on long-term clinical and social outcome of pediatric moyamoya disease

OBJECT In the study of pediatric moyamoya disease, information on long-term social outcomes and risk factors for unfavorable social outcomes remains insufficient. The authors analyzed the long-term results of surgical revascularization for pediatric patients with moyamoya disease to determine whether the involvement of a stenoocclusive lesion in the posterior cerebral artery (PCA), relatively common in pediatric moyamoya disease, represents an underlying predictor for unfavorable social outcomes. METHODS Prospectively collected data on 61 consecutive patients with moyamoya disease who had undergone combined bypass surgery were analyzed. Neuroradiological features and other baseline clinical factors were incorporated into univariate and multivariate analyses to determine any association with an unfavorable social outcome, defined as difficulty attending regular school or obtaining regular employment. RESULTS Posterior cerebral artery involvement detected by angiography on admission was noted in 22 (36.1%) of the 61 patients. Follow-up data were acquired in 56 patients (91.8%), and the mean follow-up period was 15.8 years. While transient ischemic attacks were eliminated in 52 (92.9%) of these 56 patients after surgery, and late-onset ischemic stroke was observed in only 1 patient during the follow-up period, 10 (17.9%) experienced an unfavorable social outcome. Although younger age at onset, longer duration between onset and surgery, infarction present on preoperative neuroradiological images, and PCA involvement had been identified as risk factors for an unfavorable social outcome in univariate analysis, only infarction present on preoperative images and PCA involvement remained statistically significant after multivariate adjustment. CONCLUSIONS Posterior cerebral artery involvement can be considered one of the underlying risk factors for unfavorable social outcome and should be studied further to improve social outcome in pediatric moyamoya disease.

Evaluation of carotid artery atherosclerotic plaque distribution by using long-axis high-resolution black-blood magnetic resonance imaging.

OBJECT The goal of this study was to evaluate the usefulness of long-axis black-blood MR (BB-MR) imaging for assessing plaque morphology and distribution in patients with atherosclerotic carotid artery (CA) stenosis. METHODS Sixty-eight carotid arteries in 67 patients who were scheduled to undergo CA endarterectomy or CA stent placement due to atherosclerotic stenosis were included in this study. The patients had undergone CA BB-MR imaging and digital subtraction (DS) angiography within 3 weeks of revascularization. The DS angiography studies were performed using the transfemoral artery approach with selective common CA catheterization. The BB-MR images were acquired using a 1.5-T whole-body MR imaging unit, and T1-weighted images parallel to the long axis of the artery at 1-mm intervals were obtained. Plaque distribution was evaluated by measuring the distance between the CA bifurcation and the point that appeared to be the distal extent of the plaque on BB-MR imaging (D-MR imaging) and DS angiography images (D-DS angiography). RESULTS Plaque distribution was clearly shown in 88.2% of the cases using long-axis BB-MR images, except for 8 arteries with poor image quality. In 4 arteries, D-DS angiography could not be obtained because the distal plaque end could not be confirmed. In 56 vessels, both the D-DS angiography and D-MR imaging could be measured; the mean D-MR imaging (19.75 +/- 6.85 mm [standard deviation]) was significantly longer than the average D-DS angiography (16.32 +/- 7.07 mm). CONCLUSIONS Long-axis BB-MR imaging can provide a noninvasive and accurate way to show CA plaque distribution; it is of great use not only for stroke risk assessment in patients with CA atherosclerosis but also for preoperative evaluation in patients requiring CA endarterectomy or CA stent placement.

Visualization of Periventricular Collaterals in Moyamoya Disease with Flow-sensitive Black-blood Magnetic Resonance Angiography: Preliminary Experience

Fragile abnormal collaterals in moyamoya disease, known as “moyamoya vessels,” have rarely been defined. While flow-sensitive black-blood magnetic resonance angiography (FSBB-MRA) is a promising technique for visualizing perforating arteries, as of this writing no other reports exist regarding its application to moyamoya disease. Six adults with moyamoya disease underwent FSBB-MRA. It depicted abnormal collaterals as extended lenticulostriate, thalamic perforating, or choroidal arteries, which were all connected to the medullary or insular artery in the periventricular area and supplied the cortex. This preliminary case series illustrates the potential for FSBB-MRA to reveal abnormal moyamoya vessels, which could be reasonably defined as periventricular collaterals.

Strokes Associated With Pregnancy and Puerperium: A Nationwide Study by the Japan Stroke Society

Background and Purpose— The incidence and cause of strokes associated with pregnancy and the puerperium are still not fully understood. The aim of this study was to characterize pregnancy-related strokes in Japan using a large-scale survey with current imaging techniques. Methods— A retrospective analysis was conducted based on clinical chart reviews in 736 stroke teaching hospitals certified by the Japan Stroke Society between 2012 and 2013, using a web-based questionnaire requesting the detailed clinical course without any personally identifying information. The collection rate of this questionnaire was 70.5%, with 151 pregnancy-associated strokes extracted. Results— Hemorrhagic strokes were observed in 111 cases (73.5%), ischemic strokes in 37 (24.5%), and mixed type in 3 cases (2.0%). The estimated incidence of pregnancy-associated stroke was 10.2 per 100 000 deliveries. Major causes of hemorrhage were aneurysm (19.8%), arteriovenous malformation (17.1%), pregnancy-induced hypertension (11.7%), and HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count) (8.1%). Preexisting cerebrovascular diseases responsible for hemorrhage were detected in 59 cases (53.1%). Among the ischemic strokes, 28 (75.7%) were arterial and 9 (24.3%) were venous infarctions. The most frequent cause of arterial infarctions was reversible cerebral vasoconstriction syndrome. Hemorrhagic stroke showed much poorer prognosis than ischemic stroke. Conclusions— The incidence of pregnancy-associated stroke in Japan did not seem higher than that in other Asian and Western countries. The proportion of hemorrhagic stroke among Japanese women was much higher than that in white women. Preexisting cerebrovascular diseases and reversible cerebral vasoconstriction syndrome play a key role in hemorrhagic and ischemic stroke, respectively.

Quantitative assessment of gadolinium deposition in dentate nucleus using quantitative susceptibility mapping

Gadolinium deposition in dentate nucleus (DN) has been reported after serial administration of gadolinium‐based contrast agents (GBCAs). Gadolinium complexes have paramagnetic properties; therefore, we evaluated susceptibility changes of gadolinium deposition in DN using quantitative susceptibility mapping (QSM) for patients after serial administration of GBCAs.