Osamu Narumi

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.

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.

Reduced cerebrovascular reserve is associated with an increased risk of postoperative ischemic lesions during carotid artery stenting

Background Reduced cerebrovascular reserve (CVR) is associated with increased risk of ischemic events in carotid steno-occlusive diseases. Objective To determine whether pretreatment CVR can predict postoperative ischemic lesions after carotid artery stenting (CAS) by retrospective analysis. Methods We retrospectively reviewed the medical records of 46 patients (42 men; mean age 74.2±8.3 years) who underwent CAS and preprocedural cerebral blood flow measurement by quantitative single-photon emission CT. Ischemic lesions were evaluated by diffusion-weighted image (DWI) within 72 h after the intervention. We also evaluated plaque characteristics using black-blood MR plaque imaging. Results New ipsilateral DWI-positive lesions were found in 11 cases (23.9%). Patients were classified into two groups based on the presence or absence of new DWI-positive lesions, and no significant differences in characteristics were found between the DWI-positive and DWI-negative groups, except for age and CVR of the ipsilateral middle cerebral artery (MCA) territory. The DWI-positive group was significantly older than the DWI-negative group (79.7±4.1 vs 72.5±8.6 years; p=0.0085) and had lower average regional CVR (1.4±18.2% vs 22.4±25.8%; p=0.016). MR plaque imaging showed no significant difference in relative overall plaque MR signal intensity between the two groups (1.53±0.37 vs 1.34±0.26; p=0.113). In multivariate logistic regression analysis, lower CVR of the ipsilateral MCA territory (<11%) was the only independent risk factor for new ischemic lesions following CAS (OR=6.99; 95% CI 1.17 to 41.80; p=0.033). Conclusions Impaired pretreatment CVR was associated with increased incidence of new infarction after CAS.

Dural arteriovenous fistula in the falx cerebri treated with transarterial embolization using n-butyl cyanoacrylate

Background: A dural arteriovenous fistula in the falx cerebri is a relatively rare lesion, with only two cases reported till date. One was treated with direct surgery, and the other was followed-up conservatively. Advances in catheter design and embolic materials have made safe and curative transarterial embolization of dural arteriovenous fistulas possible in the current era. Case Description: We describe a 67-year-old man with left putaminal hemorrhage who was diagnosed with an arteriovenous fistula in the anterior part of the falx cerebri that was treated with curative transarterial glue embolization through the middle meningeal artery by using n-butyl cyanoacrylate. Conclusion: Although the procedure was safely performed, understanding the potential risks of the migration of embolic materials into the ophthalmic and anterior cerebral artery system is mandatory.

Perioperative Evaluation of Cerebral Blood Flow Using 123I-labeled N-isopropyl-p-iodoamphetamine Single-Photon Emission Computed Tomography without Blood Sampling in Patients Who Underwent Carotid Artery Stenting

IntroductIon The evaluation of regional cerebral vascular reserve (rCVR) with single‐photon emission computed tomography (SPECT) is useful for predicting cerebral hyperperfusion following carotid artery stenting (CAS) and carotid endarterectomy (CEA).[1] Quantitative SPECT dual table autoradiography (DTARG) is commonly used to evaluate regional cerebral blood flow (rCBF) and rCVR. However, this method requires arterial blood sampling, which is invasive and stressful for the patients.