Association between preoperative white matter hyperintensities and postoperative new ischemic lesions on magnetic resonance imaging in patients with cognitive decline after carotid endarterectomy

Although cognitive decline after carotid endarterectomy (CEA) is mainly related to postoperative cerebral hyperperfusion, approximately 30% of patients with cognitive decline do not have postoperative cerebral hyperperfusion. In patients with acute ischemic events, the development of cognitive decline after such events is associated with the presence of chronic cerebral white matter hyperintensities (WMHs). The present prospective observational study aimed to determine whether preoperative WMHs and postoperative new ischemic lesions (PNILs) are associated with cognitive decline after CEA in patients without cerebral hyperperfusion after CEA. Brain magnetic resonance imaging (MRI) was performed preoperatively, and WMHs were graded according to the Fazekas scale in patients undergoing CEA for severe stenosis of the ipsilateral internal carotid. Diffusion-weighted MRI was performed before and after CEA to determine the development of PNILs. Neuropsychological testing was performed preoperatively and at 2 months postoperatively to determine the development of postoperative cognitive decline (PCD). In 142 patients without postoperative cerebral hyperperfusion, logistic regression analysis revealed that preoperative Fazekas scale of periventricular WMHs (PVWMHs) (95% confidence interval [CI]: 1.78-28.10; P = 0.0055) and PNILs in the eloquent areas (95% CI: 7.42-571.89; P = 0.0002) were significantly associated with PCD. The specificity and positive-predictive value for the prediction of PCD were significantly greater for the combination of preoperative Fazekas scale 2 or 3 of PVWMHs and PNILs in the eloquent areas than for each individually. Preoperative PVWMHs, PNILs in the eloquent areas, and the combination of both were associated with PCD in patients without cerebral hyperperfusion after CEA.

Feasibility of Diffusion-weighted Imaging (DWI) for Assessing Cerebrospinal Fluid Dynamics: DWI-fluidography in the Brains of Healthy Subjects

PURPOSE

The present study aimed to investigate whether diffusion-weighted imaging (DWI) can qualify and quantify cerebrospinal fluid (CSF) dynamics in the brains of healthy subjects. For this purpose, we developed new DWI-based fluidography and compared the CSF dynamics seen on the fluidography with two apparent diffusion coefficients obtained with different DWI signal models at anatomical spaces filled by CSF.

METHODS

DWI with multiple b values was performed for 10 subjects using a 7T MRI scanner. DWI-fluidography based on the DWI signal variations in different motion probing gradient directions was developed for visualizing the CSF dynamics voxel-by-voxel. DWI signals were measured using an ROI in the representative CSF-filled anatomical spaces in the brain. For the multiple DWI signals, the mono-exponential and kurtosis models were fitted and two kinds of apparent diffusion coefficients (ADCC and ADCK) were estimated in each space using the Gaussian and non-Gaussian diffusion models, respectively.

RESULTS

DWI-fluidography could qualitatively represent the features of CSF dynamics in each anatomical space. ADCs indicated that the motions at the foramen of Monro, the cistern of the velum interpositum, the quadrigeminal cistern, the Sylvian cisterns, and the fourth ventricle were more drastic than those at the subarachnoid space and anterior horns of the lateral ventricle. Those results seen in ADCs were identical to the findings on DWI-fluidography.

CONCLUSION

DWI-fluidography based on the features of DWI signals could show differences of CSF dynamics among anatomical spaces.

Association between preoperative cortical magnetic susceptibility and postoperative changes in the cerebral blood flow on cognitive improvement following carotid endarterectomy

INTRODUCTION

While patients who experience improved cognition following carotid endarterectomy (CEA) typically demonstrate restored brain perfusion after the procedure, it is worth noting that less than 50% of patients in whom postoperative cerebral blood flow (CBF) restoration is achieved actually show improved cognition after postoperatively. This suggests that factors beyond the mere restoration of CBF may play a role in postoperative cognitive improvement. Increased iron deposition in the cerebral cortex may cause neural damage, and quantitative susceptibility mapping (QSM) obtained using magnetic resonance imaging (MRI) quantifies magnetic susceptibility in the cerebral cortex, allowing for the assessment of iron deposition in vivo. The purpose of the present study was to determine whether preoperative cortical magnetic susceptibility as well as postoperative changes in CBF are associated with cognitive improvement after CEA.

METHODS

Brain MRI with a three-dimensional gradient echo sequence was preoperatively performed in 53 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≥70%), and QSM with brain surface correction and vein removal was obtained. Cortical magnetic susceptibility was measured in the cerebral hemisphere ipsilateral to surgery on QSM. Preoperatively and at two months after the surgery, brain perfusion single-photon emission computed tomography (SPECT) and neuropsychological assessments were conducted. Using these collected data, we evaluated alterations in CBF within the affected hemisphere and assessed cognitive improvements following the operation.

RESULTS

A logistic regression analysis showed that a postoperative greater increase in CBF (95% confidence interval [CI], 1.06-1.90; p = 0.0186) and preoperative lower cortical magnetic susceptibility (95% CI, 0.03-0.74; p = 0.0201) were significantly associated with postoperatively improved cognition. Although sensitivity, specificity, and positive- and negative-predictive values with the cutoff value lying closest to the upper left corner of a receiver operating characteristic curve for the prediction of postoperatively improved cognition did not differ between postoperative changes in CBF and preoperative cortical magnetic susceptibility, the specificity and the positive-predictive value were significantly greater for the combination of postoperative changes in CBF and preoperative cortical magnetic susceptibility (specificity, 95% CI, 93-100%; positive-predictive value 95% CI, 68-100%) than for the former parameter alone (specificity, 95% CI, 63-88%; positive-predictive value 95% CI, 20-64%).

CONCLUSION

Preoperative cortical magnetic susceptibility as well as postoperative changes in CBF are associated with cognitive improvement after CEA.

Correlation Between Low-Density Hematoma at 1-Week Post-Middle Meningeal Artery Embolization and Rapid Resolution of Chronic Subdural Hematoma

BACKGROUND

Temporal changes in the volume of chronic subdural hematoma (CSDH) following middle meningeal artery (MMA) embolization vary. We aimed to determine whether CSDH density on computed tomography is related to hematoma resolution following particle MMA embolization.

METHODS

Patients who underwent MMA embolization for CSDH were enrolled. The CSDHs were quantitatively divided into 2 hematoma groups based on the hematoma density at 1-week postembolization: low-density or high-density. The temporal change in the volume of CSDHs was then analyzed between the groups.

RESULTS

Thirty patients were enrolled in this study. Three patients with high-density hematomas required rescue surgery. The hematoma volume was significantly lower in low-density hematomas than in high-density hematoma at 1-week (P = 0.006), 1-month (P = 0.003), and 2-month (P = 0.004) postembolization; although the volume converged to a similar value at 3-month (P > 0.05). There was a positive correlation between hematoma density at 1-week postembolization and percentage hematoma volume at 1-week and 1-month postembolization (P = 0.004 and P < 0.001, respectively), but no correlation was observed between hematoma density before MMA embolization and percentage hematoma volume at 1-week and 1-month postembolization (P = 0.54 and P = 0.17, respectively).

CONCLUSIONS

Rapid resolution of CSDH following MMA embolization was associated with low hematoma density at 1-week postembolization. Based on hematoma density on computed tomography at 1-week postembolization, a 1-month follow-up would be sufficient in cases of low density, but a 3-month follow-up would be required in cases of high-density hematoma. Larger studies and clinical trials are needed to confirm our findings.

Previous fracture and subsequent fracture risk: a meta-analysis to update FRAX

A large international meta-analysis using primary data from 64 cohorts has quantified the increased risk of fracture associated with a previous history of fracture for future use in FRAX.

INTRODUCTION

The aim of this study was to quantify the fracture risk associated with a prior fracture on an international basis and to explore the relationship of this risk with age, sex, time since baseline and bone mineral density (BMD).

METHODS

We studied 665,971 men and 1,438,535 women from 64 cohorts in 32 countries followed for a total of 19.5 million person-years. The effect of a prior history of fracture on the risk of any clinical fracture, any osteoporotic fracture, major osteoporotic fracture, and hip fracture alone was examined using an extended Poisson model in each cohort. Covariates examined were age, sex, BMD, and duration of follow-up. The results of the different studies were merged by using the weighted β-coefficients.

RESULTS

A previous fracture history, compared with individuals without a prior fracture, was associated with a significantly increased risk of any clinical fracture (hazard ratio, HR = 1.88; 95% CI = 1.72-2.07). The risk ratio was similar for the outcome of osteoporotic fracture (HR = 1.87; 95% CI = 1.69-2.07), major osteoporotic fracture (HR = 1.83; 95% CI = 1.63-2.06), or for hip fracture (HR = 1.82; 95% CI = 1.62-2.06). There was no significant difference in risk ratio between men and women. Subsequent fracture risk was marginally downward adjusted when account was taken of BMD. Low BMD explained a minority of the risk for any clinical fracture (14%), osteoporotic fracture (17%), and for hip fracture (33%). The risk ratio for all fracture outcomes related to prior fracture decreased significantly with adjustment for age and time since baseline examination.

CONCLUSION

A previous history of fracture confers an increased risk of fracture of substantial importance beyond that explained by BMD. The effect is similar in men and women. Its quantitation on an international basis permits the more accurate use of this risk factor in case finding strategies.

Assessment of magnetic field interactions and heating for cerebral aneurysm flow diverters during 7T MRI

Flow diverters (FDs) are utilized for a wide range of aneurysms, but show safety issues such as adverse interactions with static magnetic fields (displacement force and torque) and radiofrequency-induced heating during magnetic resonance imaging (MRI). The present study aimed to assess these adverse interactions in a 7-tesla (7T) static magnetic field and radiofrequency-induced heating during a 7T MRI for two types of FD. Displacement force and magnetically induced torque were assessed using the deflection angle method and low friction surface method, respectively. To assess heating, each FD was set in a phantom filled with gelled-saline mixed with polyacrylic acid and underwent a 7T MRI using a three-dimensional fast spin echo method. Displacement force and magnetically induced torque in the 7T static magnetic field were undetectable, and radiofrequency-induced heating during 7T MRI remained ≤ 0.6 °C for both types of FD, suggesting that magnetic field interactions and heating on FDs during a 7T MRI are acceptable from a safety perspective.

Influence of atherosclerotic burden on adult patients with ischemic moyamoya disease: combined analysis of two prospective cohorts

OBJECTIVE

This study aimed to determine the influence of atherosclerotic risk factors on initial and further cerebrovascular events in adult patients with moyamoya disease (MMD) by combined analysis of two prospective cohorts in which patients received pharmacotherapy alone and were prospectively followed-up for 5 years.

METHODS

In 71 patients, smoking status, home blood pressure, hemoglobin (Hb)A1c and low-density lipoprotein cholesterol (LDL-chol) were checked at inclusion and at further cerebrovascular event or at the end of 5-year follow-up. When a patient had daily smoking, increased HbA1c, increased LDL-chol, increased systolic blood pressure, or increased diastolic blood pressure, the patient was categorized as showing atherosclerotic burden. Angiographic disease progression was determined using changes on magnetic resonance angiography.

RESULTS

Eleven patients showed angiographic disease progression and seven of these 11 patients experienced further cerebrovascular events during the follow-up period. The remaining 60 patients did not exhibit either condition. At inclusion, the incidence of atherosclerotic burden was significantly greater in patients without angiographic disease progression (80%) than in those with such progression (45%; p = 0.0249). For patients without angiographic disease progression, values or incidence of almost all variables showed significant interval decreases at the end of 5-year follow-up (p < 0.05).

CONCLUSIONS

Adult patients with ischemic MMD who do not exhibit angiographic disease progression appear more strongly affected by atherosclerotic burden at the initial onset of cerebrovascular events than those exhibiting angiographic disease progression. A reduction in atherosclerotic burden by medical treatments for the former patients prevents further cerebrovascular events.

Symptomatic subdural hemorrhage following heart valve surgery: a retrospective cohort study

OBJECTIVE

Subdural hemorrhage (SDH) has been reported to be the most frequent intracranial hemorrhagic complication following open heart surgery; however, its clinical features and pathophysiology remain unclear. The aim of this retrospective study was to elucidate the incidence, clinical course, and factors associated with the development of symptomatic SDH following heart valve surgery.

METHODS

A retrospective review of medical records on the development of symptomatic SDH after heart valve surgery involving cardiopulmonary bypass (CPB) from April 2011 to March 2016 was performed. Patients who had undergone preoperative cranial computed tomography (CT) or brain magnetic resonance imaging (MRI) were included in this study, and factors associated with SDH following heart valve surgery were analyzed. When neurological symptoms developed after heart valve surgery, cranial CT or brain MRI was performed.

RESULTS

A total of 556 patients who had undergone heart valve surgery were analyzed. Among these patients, symptomatic SDH occurred in 11 (2.0%). The mean duration of symptomatic onset was 10.1 days (range 2-37 days). Ten of 11 patients (90.9%) developed SDH in the posterior fossa or occipital convexity. Logistic regression analysis revealed longer aortic clamp time (95% CI 1.00-1.10, p = 0.04), higher dose of heparin after surgery (95% CI 1.00-1.02, p = 0.001), and higher pulmonary artery pressure (PAP) just before disconnection of the CPB (95% CI 1.01-1.37, p = 0.04) as significantly associated with the development of SDH.

CONCLUSIONS

The incidence of symptomatic SDH following heart valve surgery was 2.0%. Symptoms due to SDH usually developed a few days to 1 month after surgery. Surprisingly, most SDHs developed in the posterior fossa or occipital convexity following heart valve surgery. A longer aortic clamp time, higher dose of heparin after surgery, and higher PAP just before disconnection of the CPB were related to the development of symptomatic SDH following heart valve surgery.

Effect of the addition of 123I-iomazenil single-photon emission computed tomography to brain perfusion single-photon emission computed tomography on the detection accuracy of misery perfusion in adult patients with ischemic moyamoya disease

OBJECTIVE

The present prospective study aimed to determine whether the addition of ¹²³I-iomazenil (IMZ) single-photon emission computed tomography (SPECT) to brain perfusion SPECT could improve the detection accuracy of misery perfusion on positron emission tomography (PET) in adult patients with ischemic moyamoya disease (MMD).

METHODS

Oxygen extraction fraction (OEF) and brain perfusion were assessed using ¹⁵O gas PET and N-isopropyl-p-[¹²³I]-iodoamphetamine (IMP) SPECT, respectively, in 137 patients. IMZ SPECT was also performed. Regions of interest (ROIs) were automatically placed in the five middle cerebral artery (MCA) territories ipsilateral to the symptomatic cerebral hemisphere and in the contralateral posterior cerebral artery territory using a three-dimensional stereotaxic ROI template. The radioactive count of the MCA ROI to the contralateral posterior cerebral artery ROI was calculated on IMP SPECT (relative SPECT-IMP uptake) and IMZ SPECT (relative SPECT-IMZ uptake). The relative SPECT-IMZ uptake to the relative SPECT-IMP uptake was also calculated (relative SPECT-IMZ/IMP uptake). Of the five MCA ROIs in the symptomatic cerebral hemisphere in each patient, the ROI with the highest PET-OEF value (one ROI per patient) was selected for analysis.

RESULTS

Significant correlations were observed between the PET-OEF and relative SPECT-IMP uptake (correlation coefficient, - 0.683) and relative SPECT-IMZ/IMP uptake (correlation coefficient, 0.875). The area under the receiver operating characteristic curve for detecting misery perfusion (PET-OEF > 51.3%) was significantly greater for the relative SPECT-IMZ/IMP uptake than for the relative SPECT-IMP uptake (difference between areas, 0.080; p = 0.0004). The sensitivity, specificity, and positive- and negative-predictive values for the relative SPECT-IMZ/IMP uptake for detecting misery perfusion were 100%, 92%, 81%, and 100%, respectively. The specificity and positive-predictive value were significantly greater for the relative SPECT-IMZ/IMP uptake than for the relative SPECT-IMP uptake.

CONCLUSIONS

The addition of IMZ SPECT to brain perfusion SPECT improves the detection accuracy of misery perfusion on PET in adult patients with ischemic MMD.

Prediction of cerebral hyperperfusion following carotid endarterectomy using intravoxel incoherent motion magnetic resonance imaging

OBJECTIVES

One of the risk factors for cerebral hyperperfusion following carotid endarterectomy (CEA) is a chronic reduction in cerebral perfusion pressure due to internal carotid artery (ICA) stenosis, which is clinically detected as increased cerebral blood volume (CBV). The perfusion fraction (f) is one of the intra-voxel incoherent motion (IVIM) parameters obtained using magnetic resonance (MR) imaging that theoretically reflects CBV. The present study aimed to determine whether preoperative IVIM-f on MR imaging predicts development of cerebral hyperperfusion following CEA.

MATERIALS AND METHODS

Sixty-eight patients with unilateral ICA stenosis (≥ 70%) underwent preoperative diffusion-weighted 3-T MR imaging, and IVIM-f maps were generated from these data. Quantitative brain perfusion single-photon emission computed tomography (SPECT) was performed before and immediately after CEA. Regions-of-interest (ROIs) were automatically placed in the bilateral middle cerebral artery territories in all images using a three-dimensional stereotactic ROI template, and affected-to-contralateral ratios in the ROIs were calculated on IVIM-f maps.

RESULTS

Nine patients (13%) exhibited postoperative hyperperfusion (cerebral blood flow increases of ≥ 100% compared with preoperative values in the ROIs on brain perfusion SPECT). Only high IVIM-f ratios were significantly associated with the occurrence of postoperative hyperperfusion (95% confidence interval, 253.8-6774.2; p = 0.0031) on logistic regression analysis. The sensitivity, specificity, and positive and negative predictive values of the IVIM-f ratio to predict the occurrence of postoperative hyperperfusion were 100%, 81%, 45%, and 100%, respectively.

CONCLUSIONS

Preoperative IVIM-f on MR imaging can predict development of cerebral hyperperfusion following CEA.

NI-10 CLINICAL BENEFITS FROM ONE-SHOT BEVACIZUMAB BEFORE A RESECTION OF GLIOBLASTOMA

Purpose

We aimed to clarify of clinical impacts from preoperative administration of bevacizumab (BEV) in patients with newly diagnosed glioblastoma.

Methods

Subjects were 17 patients who met the entry criteria, and were administered with BEV (10 mg/kg) one time before surgery. Between phases before and after BEV administration, we compared KPS and volumes of hyperintense areas on FLAIR and enhanced areas on T1-weighted imaging with contrast media (Gd-T1WI). Tumor resection was carried out at least three weeks after BEV. Also between phases immediately before and after operation, volumes of hyperintense areas on FLAIR and enhanced areas on Gd-T1WI (= tumor removal rate) were compared. These were compared with those in the control group of patients who received tumor resection without BEV.

Results

One-shot BEV led to significant improvement of KPS and significant volume reductions of hyperintense areas on FLAIR (43.8±26.3%) and enhanced areas on Gd-T1WI (34.6±18.2%). No patients showed any adverse effects around surgery. On MRI after surgery, volume-reduction rates of hyperintense areas on FLAIR and enhanced areas on Gd-T1WI were 44.7±24.7% and 96.2±5.4%, respectively. Compared with control group, a significant difference was identified in the reduction rate of hyperintense areas, but not in that of enhanced areas.

Conclusions

One-shot administration with BEV reduced both volumes of hyperintense areas on FLAIR and enhanced areas on Gd-T1WI, thereby improved KPS before surgery. Preoperative BEV was safe for tumor resections but did not affect to tumor removal rate. We speculated a significant volume reduction of hyperintense areas on FLAIR might have been led by continuous effect from BEV rather than an increase of resected volume.

Development of cerebral microbleeds and its impact on cognitive function in adult patients receiving medical management alone for ischemic moyamoya disease: supplementary analysis of a 5-year prospective cohort

OBJECTIVE

De novo cerebral microbleeds (CMBs) on T2*-weighted magnetic resonance imaging (MRI) develop over time in adult moyamoya disease (MMD) and are generally associated with a decline in global cognitive function. The present supplementary analysis of a 5-year prospective cohort aimed to elucidate the incidence of an interval increase in CMBs in adult patients receiving medical management alone for ischemic MMD and its impact on cognitive function.

METHODS

Sixty-four patients without misery perfusion in the symptomatic cerebral hemispheres at inclusion who did not experience any further ischemic symptoms or new hemorrhagic events during a 5-year follow-up period underwent T2*-weighted MRI and five kinds of neuropsychologic tests at inclusion and the end of the 5-year follow-up.

RESULTS

When T2*-weighted MRI was compared between inclusion and the end of the 5-year follow-up, 10 patients (15%) had an interval increase in CMBs in the symptomatic cerebral hemisphere at inclusion. The scores from two kinds of neuropsychologic tests significantly deteriorated at the end of the 5-year follow-up compared with those at inclusion in patients with an interval increase in CMBs, whereas the scores of four kinds of neuropsychologic tests significantly improved at the end of the 5-year follow-up compared with those at inclusion in patients without interval increases in CMBs, asymptomatic ischemic lesions, or angiographic disease progression.

CONCLUSIONS

The incidence of an interval increase in CMBs was 15% per 5 years in adult patients receiving medical management alone for ischemic MMD, and this increase was associated with a decline in cognitive decline.

Small Sphenoid Ridge as a Factor Associated with Laterally Deviated Proximal Sylvian Fissure in Patients Undergoing Pterional Craniotomy

BACKGROUND

During the pterional-transsylvian approach, we sometimes encounter the proximal Sylvian fissure (SF) deviating laterally beyond the fold of the sphenoidal ridge (SR) and experience difficulty dissecting the SF due to the deep and oblique dissection plane. In the present study, we explored the association between the height of the SR and lateral deviation of the SF during the pterional-transsylvian approach.

METHODS

The association between the height of the SR on axial computed tomography and the presence of a laterally deviated SF was evaluated by reviewing patients who had undergone pterional craniotomy.

RESULTS

Among the 52 patients included, lateral deviation of the SF was observed in 8 patients (13.4%). The median height of the SR was significantly smaller in patients with laterally deviated SF (6.0 mm) than in patients with non-deviating SF (13.4 mm; P < 0.0001). The oculomotor nerves and middle fossa were observed at the edge of the dissection plane of the SF in all patients with a laterally deviating SF, while medial structures such as the internal carotid artery or optic nerve were observed in patients with non-deviating SF.

CONCLUSIONS

Small SR was associated with lateral deviation of the proximal SF.

Update of the fracture risk prediction tool FRAX: a systematic review of potential cohorts and analysis plan

We describe the collection of cohorts together with the analysis plan for an update of the fracture risk prediction tool FRAX with respect to current and novel risk factors. The resource comprises 2,138,428 participants with a follow-up of approximately 20 million person-years and 116,117 documented incident major osteoporotic fractures.

INTRODUCTION

The availability of the fracture risk assessment tool FRAX® has substantially enhanced the targeting of treatment to those at high risk of fracture with FRAX now incorporated into more than 100 clinical osteoporosis guidelines worldwide. The aim of this study is to determine whether the current algorithms can be further optimised with respect to current and novel risk factors.

METHODS

A computerised literature search was performed in PubMed from inception until May 17, 2019, to identify eligible cohorts for updating the FRAX coefficients. Additionally, we searched the abstracts of conference proceedings of the American Society for Bone and Mineral Research, European Calcified Tissue Society and World Congress of Osteoporosis. Prospective cohort studies with data on baseline clinical risk factors and incident fractures were eligible.

RESULTS

Of the 836 records retrieved, 53 were selected for full-text assessment after screening on title and abstract. Twelve cohorts were deemed eligible and of these, 4 novel cohorts were identified. These cohorts, together with 60 previously identified cohorts, will provide the resource for constructing an updated version of FRAX comprising 2,138,428 participants with a follow-up of approximately 20 million person-years and 116,117 documented incident major osteoporotic fractures. For each known and candidate risk factor, multivariate hazard functions for hip fracture, major osteoporotic fracture and death will be tested using extended Poisson regression. Sex- and/or ethnicity-specific differences in the weights of the risk factors will be investigated. After meta-analyses of the cohort-specific beta coefficients for each risk factor, models comprising 10-year probability of hip and major osteoporotic fracture, with or without femoral neck bone mineral density, will be computed.

CONCLUSIONS

These assembled cohorts and described models will provide the framework for an updated FRAX tool enabling enhanced assessment of fracture risk (PROSPERO (CRD42021227266)).

Long-term outcomes, including the survival rate and period to death, in patients over 80 years old after ruptured cerebral aneurysm clipping

OBJECTIVE

This study aimed to identify the long-term outcomes, including the survival rate, period to death, causes of death, and predictors of poor outcomes, in patients aged over 80 years who underwent surgical clipping for a ruptured anterior circulation aneurysm.

MATERIALS AND METHODS

In this retrospective observational study, the medical records of patients from April 1, 1994, to June 30, 2019, were evaluated. All patients underwent surgical clipping within 72 h of subarachnoid hemorrhage (SAH) onset. Information on the patient, SAH, and outcomes were collected.

RESULTS

The mean hospitalization and long-term follow-up periods for all patients were 54.5 days and 53.3 months, respectively. The period to death was significantly shorter in patients with modified Rankin scale (mRS) of 4-5 than for those with an mRS of 0-3 at discharge (p=0.001). The Kaplan-Meier method using the log-rank test demonstrated that patients with an mRS of 4-5 at discharge had a significantly lower survival rate compared to those with an mRS of 0-3 at discharge (p<0.05). Univariate analysis revealed that the proportion of patients with Hunt and Hess grade and presence of surgical complications were significantly larger in the group with an mRS of 4-5 than in that with an mRS of 0-3 at discharge (p=0.0013 and 0.011, respectively). Multivariate analysis demonstrated that presence of surgical complications was the only independent predictor of poor outcomes (p=0.043, odds ratio [OR] 7.937, 95% confidence interval [CI] 1.061-59.38). The Kaplan-Meier method using the log-rank test demonstrated that patients with surgical complications had a significantly lower survival rate compared to those with no surgical complications (p<0.05).

CONCLUSIONS

Especially in patients aged over 80 years, those with H-H grade 2 and a good clinical condition can be candidates for surgical clipping, whereas avoiding surgical complications is essential for achieving good outcomes.

Assessment of Heating on Titanium Alloy Cerebral Aneurysm Clips during 7T MRI

BACKGROUND AND PURPOSE

Patients with cerebral aneurysms often undergo MR imaging after microsurgical clipping. Ultra-high-field MR imaging at 7T may provide high diagnostic capability in such clinical situations. However, titanium alloy clips have safety issues such as adverse interactions with static magnetic fields and radiofrequency-induced heating during 7T MR imaging. The purpose of this study was to quantitatively assess temperature increases on various types of titanium alloy aneurysm clips during 7T MR imaging.

MATERIALS AND METHODS

Five types of titanium alloy aneurysm clips were tested, including combinations of short, long, straight, angled, and fenestrated types. Each clip was set in a phantom filled with gelled saline mixed with polyacrylic acid and underwent 7T MR imaging with 3D T1WI with a spoiled gradient recalled acquisition in the steady-state technique. Temperature was chronologically measured at the tips of the clip blade and head, angled part of the clip, and 5 mm from the tip of the clip head using MR imaging-compatible fiber-optic thermometers.

RESULTS

Temperature increases at all locations for right-angled and short straight clips were <1°C. Temperature increases at the angled part for the 45° angled clip and the tip of the clip head for the straight fenestrated clip were >1°C. Temperature increases at all locations for the long straight clip were >2°C.

CONCLUSIONS

Temperature increases on the right-angled and short straight clips remained below the regulatory limit during 7T MR imaging, but temperature increases on the 45° angled, straight fenestrated, and long straight clips exceeded this limit.

Outcomes of medical management alone for adult patients with cerebral misery perfusion due to ischemic moyamoya disease

OBJECTIVES

Although revascularization surgery is recommended for adult patients with moyamoya disease (MMD) who present with ischemic symptoms due to hemodynamic compromise, the clinical course of such patients who are treated with medical management alone remains unclear. Here, we report outcomes of adult patients with cerebral misery perfusion due to ischemic MMD who received medical management alone.

MATERIALS AND METHODS

We prospectively followed up patients who showed misery perfusion in the symptomatic cerebral hemisphere on ¹⁵O gas positron emission tomography (PET) and received strict medical management alone after refusing revascularization surgery.

RESULTS

Of 57 patients who showed symptomatic misery perfusion on ¹⁵O gas PET, three (5%) were included into the present study. Two of these patients suffered further ischemic events at 7 and 8 months after inclusion, after which, their modified Rankin disability scale scores deteriorated. In the remaining patient, fatal intracerebral hemorrhage developed at 10 months after inclusion.

CONCLUSIONS

These findings suggest that receiving medical management alone is associated with considerably poor outcomes for adult patients with cerebral misery perfusion due to ischemic MMD.

Angiographic, Cerebral Hemodynamic, and Cognitive Outcomes of Indirect Revascularization Surgery Alone for Adult Patients With Misery Perfusion due to Ischemic Moyamoya Disease

BACKGROUND

Revascularization surgery for adult patients with ischemic moyamoya disease (MMD) may improve both cognitive function and cerebral perfusion.

OBJECTIVE

To determine angiographic, cerebral hemodynamic, and cognitive outcomes of indirect revascularization surgery alone for adult patients with misery perfusion due to ischemic MMD (IDR group) and to test the superiority of indirect revascularization surgery for cognitive improvement by conducting comparisons with historical control patients who had undergone direct revascularization surgery (DR group) through prospective cohort study with historical controls.

METHODS

Twenty adult patients with cerebral misery perfusion underwent encephalo-duro-myo-arterio-pericranial-synangiosis alone. Cerebral angiography through arterial catheterization, brain perfusion single-photon emission computed tomography, and neuropsychological testing were performed preoperatively and at 6 months postoperatively.

RESULTS

In 17 patients of the IDR group, collateral flows that were newly formed after surgery on angiograms fed more than one-third of the middle cerebral artery (MCA) cortical territory. In the IDR group, perfusion in the MCA territory was significantly increased after surgery (P < .0001), and the difference in MCA perfusion between before and after surgery was significantly greater (P = .0493) compared with the DR group. Improved cognition was significantly more frequent in the IDR group (65%) than in the DR group (31%, P = .0233).

CONCLUSION

Indirect revascularization surgery alone forms sufficient collateral circulation, improves cerebral hemodynamics, and recovers cognitive function in adult patients with misery perfusion due to ischemic MMD. The latter 2 beneficial effects may be higher when compared with patients undergoing direct revascularization surgery.

Recovery of cortical neurotransmitter receptor function and its impact on cognitive improvement after indirect revascularization surgery alone for adult patients with ischemic moyamoya disease: 123I-iomazenil single-photon emission computed tomography study

OBJECTIVE

Brain ¹²³I-iomazenil single-photon emission computed tomography (SPECT) can assess the distribution of the binding potential of central benzodiazepine receptors in the cerebral cortex. This binding potential may reflect neuronal function in viable tissues. The present prospective study using brain ¹²³I-iomazenil SPECT aimed to determine whether improvements in cognitive function after indirect revascularization surgery alone are associated with postoperative recovery in neurotransmitter receptor function in the affected cerebral hemisphere among adult patients with moyamoya disease (MMD) accompanied by ischemic presentation due to misery perfusion.

METHODS

Twenty-two patients who underwent indirect revascularization surgery alone also underwent brain SPECT scanning at 180 minutes after ¹²³I-iomazenil administration and neuropsychological testing before and at 6 months after surgery. The affected-to-contralateral cerebral hemispheric asymmetry of tracer uptake before and after surgery was then calculated.

RESULTS

The asymmetry of tracer uptake was significantly increased after surgery (p < 0.0001). A significant difference between the pre- and postoperative asymmetry of tracer uptake was seen in patients with improved cognition compared with those with unchanged cognition (p = 0.0001). The area under the receiver operating characteristic curve was 0.99 for the difference between the pre- and postoperative asymmetry of tracer uptake to assess the ability to discriminate patients with improved cognition from those with unchanged cognition.

CONCLUSIONS

Improvements in cognitive function after indirect revascularization surgery alone are associated with postoperative recovery in the binding potential of central benzodiazepine receptors in the affected cerebral hemisphere in adult patients with MMD accompanied by ischemic presentation due to misery perfusion.

Delayed development of cerebral atrophy after cerebral hyperperfusion following arterial bypass for adult patients with ischemic moyamoya disease: supplementary analysis of a 5-year prospective cohort

BACKGROUND

Adult patients with moyamoya disease (MMD) occasionally exhibit cerebral hyperperfusion after arterial bypass surgery, leading to persistent cognitive decline. The present supplementary analysis of a prospective 5-year cohort study aimed to determine whether cerebral hyperperfusion after arterial bypass surgery for adult patients with misery perfusion due to ischemic MMD causes cerebral atrophy, and whether the development of cerebral atrophy is related to persistent cognitive decline.

METHODS

In total, 31 patients who underwent arterial bypass surgery also underwent fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) and neuropsychological testing before surgery and at the end of a 5-year follow-up. The development of cerebral hyperperfusion and hyperperfusion syndrome after surgery was defined based on brain perfusion single-photon emission computed tomography (SPECT) findings and clinical symptoms. Univariate and multivariate logistic regression analyses of factors related to the development of cerebral atrophy on FLAIR MRI or cognitive decline on neuropsychological testing at the end of the 5-year follow-up were performed.

RESULTS

Eleven patients (35%) developed cerebral atrophy in the frontal lobe where the superficial temporal artery was anastomosed. Cerebral hyperperfusion on brain perfusion SPECT (odds ratio [OR], 50.6; p = 0.0008) or cerebral hyperperfusion syndrome (OR, 41.8; p = 0.0026) was independently associated with the development of cerebral atrophy, and cerebral atrophy development was significantly associated with cognitive decline (OR, 47.7; p = 0.0010).

CONCLUSIONS

Cerebral hyperperfusion after arterial bypass surgery for adult patients with misery perfusion due to ischemic MMD can cause cerebral atrophy related to persistent cognitive decline.

Intracranial aneurysm rupture within three days after receiving mRNA anti-COVID-19 vaccination: Three case reports

Background:

Although neurological adverse events have been reported after receiving coronavirus disease 2019 (COVID-19) vaccines, associations between COVID-19 vaccination and aneurysmal subarachnoid hemorrhage (SAH) have rarely been discussed. We report here the incidence and details of three patients who presented with intracranial aneurysm rupture shortly after receiving messenger ribonucleic acid (mRNA) COVID-19 vaccines.

Case Description:

We retrospectively reviewed the medical records of individuals who received a first and/ or second dose of mRNA COVID-19 vaccine between March 6, 2021, and June 14, 2021, in a rural district in Japan, and identified the occurrences of aneurysmal SAH within 3 days after mRNA vaccination. We assessed incidence rates (IRs) for aneurysmal SAH within 3 days after vaccination and spontaneous SAH for March 6–June 14, 2021, and for the March 6–June 14 intervals of a 5-year reference period of 2013–2017. We assessed the incidence rate ratio (IRR) of aneurysmal SAH within 3 days after vaccination and spontaneous SAH compared to the crude incidence in the reference period (2013–2017). Among 34,475 individuals vaccinated during the study period, three women presented with aneurysmal SAH (IR: 1058.7/100,000 person-years), compared with 83 SAHs during the reference period (IR: 20.7/100,000 persons-years). IRR was 0.026 (95% confidence interval [CI] 0.0087–0.12; P < 0.001). A total of 28 spontaneous SAHs were verified from the Iwate Stroke Registry database during the same period in 2021 (IR: 34.9/100,000 person-years), and comparison with the reference period showed an IRR of 0.78 (95%CI 0.53–1.18; P = 0.204). All three cases developed SAH within 3 days (range, 0–3 days) of the first or second dose of BNT162b2 mRNA COVID-19 vaccine by Pfizer/BioNTech. The median age at the time of SAH onset was 63.7 years (range, 44– 75 years). Observed locations of ruptured aneurysms in patients were the bifurcations of the middle cerebral artery, internal carotid-posterior communicating artery, and anterior communicating artery, respectively. Favorable outcomes (modified Rankin scale scores, 0–2) were obtained following microsurgical clipping or intra-aneurysm coiling.

Conclusion:

Although the advantages of COVID-19 vaccination appear to outweigh the risks, pharmacovigilance must be maintained to monitor potentially fatal adverse events and identify possible associations.

Optimal timing for measuring cerebral blood flow after acetazolamide administration to detect preexisting cerebral hemodynamics and metabolism in patients with bilateral major cerebral artery steno-occlusive diseases: 15O positron emission tomography studies

The present study determined the optimal timing of scanning for measurement of cerebral blood flow (CBF) after acetazolamide (ACZ) administration for detection of preexisting cerebral hemodynamics and metabolism in bilateral major cerebral artery steno-occlusive diseases. Thirty three patients underwent ¹⁵O gas positron emission tomography (PET) and each parameter was obtained in the bilateral middle cerebral artery (MCA) territories. CBF was also obtained using H₂ ¹⁵O PET scanning performed at baseline and at 5, 15, and 30 min after ACZ administration. Relative CBF at each time point after ACZ administration to baseline CBF was calculated. For MCA territories with normal cerebral blood volume (CBV) and cerebral metabolic rate of oxygen (CMRO₂), CBF continued increasing until 15 min after ACZ administration. For MCA territories with abnormally increased CBV, CBF decreased 5 min after ACZ administration. After that, CBF continued increasing until 30 min after ACZ administration. For MCA territories with abnormally decreased CMRO₂, CBF did not change 5 min after ACZ administration. Ten min later, CBF increased. The accuracy to detect abnormally increased CBV was significantly greater for relative CBF₅ than for relative CBF₁₅. The accuracy to detect abnormally decreased CMRO₂ was significantly greater for relative CBF₅ or CBF₁₅ than for relative CBF₃₀. For detecting abnormally increased oxygen extraction fraction, the accuracy did not differ among each relative CBF. These findings suggested that CBF measurement at 5 min after ACZ administration is the optimal timing for detection of preexisting cerebral hemodynamics and metabolism in bilateral major cerebral artery steno-occlusive diseases.

Long-Term Cognitive Changes after Revascularization Surgery in Adult Patients with Ischemic Moyamoya Disease

Introduction

Revascularization surgery for adult moyamoya disease (MMD) with ischemic presentation changes cognitive function and prevents further cerebral ischemic events. Most studies however repeated neuropsychological evaluation within 1 year after surgery. Our previous prospective cohort study of adult patients with MMD with misery perfusion who underwent direct revascularization surgery showed cognitive improvement and decline in 31% and 44%, respectively, of the patients 2 months after surgery. The present prospective study aimed to elucidate the 5-year cognitive changes after direct revascularization surgery in adult patients with cerebral misery perfusion due to ischemic MMD by following the same patients.

Methods

In total, 31 patients were prospectively followed up for 5 years after direct revascularization surgery. Five types of neuropsychological tests were performed preoperatively, 2 months after surgery, and at the end of the 5-year follow-up. Cerebral blood flow (CBF) in the symptomatic cerebral hemisphere relative to that in the ipsilateral cerebellar hemisphere (hemispheric relative CBF [RCBF]) was measured using brain perfusion single-photon emission computed tomography preoperatively and at the end of the 5-year follow-up.

Results

Based on results of pre- and postoperative neuropsychological tests, 11, 10, and 10 patients showed cognitive improvement, no change in cognitive function, and cognitive decline, respectively, at the end of the 5-year follow-up. These ratios were not significantly different compared with those 2 months after surgery (cognitive improvement, no change in cognitive function, and cognitive decline in 10, 8, and 13 patients, respectively). Although hemispheric RCBF was significantly greater at the end of the 5-year follow-up than before surgery in patients with cognitive improvement (80.7 ± 6.1% vs. 92.9 ± 5.5%; p = 0.0033) and in those showing no change in cognitive function (85.6 ± 3.5 vs. 91.5 ± 5.2%; p = 0.0093), this value was significantly lower at the end of the 5-year follow-up than before surgery in patients with cognitive decline (83.8 ± 3.7 vs. 81.0 ± 5.8%; p = 0.0367).

Conclusion

One-third of adult patients with cerebral misery perfusion due to ischemic MMD who underwent direct revascularization surgery exhibited cognitive improvement, and one-third exhibited decline at the end of the 5-year follow-up. The former and latter patients had increased and decreased CBF, respectively, in the affected cerebral hemisphere at the end of the 5-year follow-up compared with preoperative brain perfusion.

De Novo Cerebral Microbleeds and Cognitive Decline in Cerebral Hyperperfusion After Direct Revascularization for Adult Moyamoya Disease

OBJECTIVES

Adult patients with moyamoya disease (MMD) occasionally develop cognitive decline due to cerebral hyperperfusion following direct revascularization surgery. However, how the hyperperfusion phenomenon contributes to declines in cognitive function remains unclear. The present supplementary analysis of a prospective study aimed to determine whether cerebral hyperperfusion following direct revascularization surgery for adult MMD with ischemic presentation and misery perfusion leads to development of de novo cerebral microbleeds (CMBs) and whether postoperative cognitive decline is related to these CMBs.

MATERIALS AND METHODS

In total, 32 patients who underwent direct revascularization surgery also underwent T2*-weighted magnetic resonance imaging (T2*WI) and neuropsychological testing before and 2 months after surgery. Development of cerebral hyperperfusion and hyperperfusion syndrome following surgery was defined based on brain perfusion single-photon emission computed tomography (SPECT) findings and clinical symptoms.

RESULTS

Cerebral hyperperfusion on brain perfusion SPECT (95% confidence interval [CI], 1.1-10.8; p = 0.0175) or cerebral hyperperfusion syndrome (95%CI, 1.3-15.3; p = 0.0029) was significantly associated with postoperatively increased CMBs on T2*WI. Postoperatively increased CMBs were significantly associated with postoperative cognitive decline (95%CI, 1.8-20.4, p = 0.0041). For patients with cerebral hyperperfusion on brain perfusion SPECT, the incidence of postoperative cognitive decline was significantly greater in patients with than in those without postoperatively increased CMBs (p = 0.0294).

CONCLUSIONS

Cerebral hyperperfusion following direct revascularization surgery for adult MMD with ischemic presentation and misery perfusion contributes to the development of de novo CMBs and postoperative cognitive decline is related to these CMBs.

Angiographic disease progression in medically treated adult patients with ischemic moyamoya disease without cerebral misery perfusion: supplementary analysis of a 5-year prospective cohort

Angiographic disease progression reportedly develops in adult moyamoya disease (MMD). However, more than half of patients analyzed underwent revascularization surgery. The present supplementary analysis of a 5-year prospective cohort with follow-up using magnetic resonance angiography (MRA) and cerebral blood flow (CBF) measurements was to elucidate the incidence and clinical features of angiographic disease progression in adult patients receiving medical management alone for ischemic MMD. Sixty-eight patients without misery perfusion in the symptomatic cerebral hemispheres underwent MRA and CBF measurement using brain perfusion single-photon emission computed tomography at inclusion and at the end of the 5-year follow-up. When neurological symptoms recurred or newly developed during the 5-year follow-up period, additional MRA and CBF measurements were also performed at that time. All four patients with further ischemic events during the 5-year follow-up period exhibited angiographic disease progression on MRA at such events. Of the remaining 64 patients without further events during the 5-year follow-up period, four exhibited angiographic disease progression on MRA at the end of the 5-year follow-up. CBF was significantly lower at the time of further ischemic events or at the end of the 5-year follow-up than at inclusion in eight patients with angiographic disease progression (p = 0.0117). The incidence of angiographic disease progression was 12% for 5 years in medically treated adult patients with ischemic MMD without cerebral misery perfusion. Patients with further ischemic events always exhibited angiographic disease progression. Cerebral perfusion was reduced in patients with angiographic disease progression even when further ischemic events did not occur.

Five-Year Outcomes of Medical Management Alone for Adult Patients with Ischemic Moyamoya Disease without Cerebral Misery Perfusion

INTRODUCTION

No clear guidelines for treating adult patients with ischemic moyamoya disease (MMD) without cerebral hemodynamic compromise such as misery perfusion have been established. Our previous prospective cohort study of adult patients with MMD without misery perfusion who were treated with medical management alone, including an antiplatelet drug, showed a recurrent ischemic event rate of 3% per 2 years. The present prospective study aimed to elucidate the 5-year clinical, cerebral perfusion, and cognitive outcomes of medical management alone for Japanese adult patients with ischemic MMD without cerebral misery perfusion by following the same patients for another 3 years.

METHODS

In total, 68 patients without recurrent events at a 2-year follow-up were prospectively followed up for another 3 years. Cerebral blood flow (CBF) in the symptomatic cerebral hemisphere was measured using brain perfusion single-photon emission computed tomography at inclusion and at the end of the subsequent 3-year follow-up. Neuropsychological testing was performed at inclusion and at the end of the initial 2- and subsequent 3-year follow-ups.

RESULTS

During the subsequent 3-year follow-up, 2 patients (3%) developed further ischemic events. In patients without further ischemic events, CBF was significantly greater at the end of the subsequent 3-year follow-up than at inclusion (p = 0.0037), and all neuropsychological test scores improved or remained unchanged at the end of initial 2- and subsequent 3-year follow-ups compared with that at inclusion.

CONCLUSION

In adult patients receiving medical management alone for ischemic MMD without cerebral misery perfusion, the incidence of further ischemic events was 6% per 5 years and did not change between the initial 2 years after the last is-chemic event and the subsequent 3 years. In patients without further ischemic events, CBF and cognitive function had not deteriorated at 5 years after the last ischemic event.

Feasibility and safety of partial resection of the anterior insular cortex for microsurgical treatment of middle cerebral artery aneurysms located in the limen recess: patient series

BACKGROUND

When performing clip ligation of superior projecting aneurysms of the proximal (M1) segment of the middle cerebral artery (MCA), meticulous sylvian fissure dissection alone may be inadequate for safe clip application, especially in cases in which the aneurysm is buried in the limen recess, since the limen insulae may be positioned lateral to the aneurysm. In the present patient series, the authors present their surgical technique for clip ligation of aneurysms located in the limen recess, with partial resection of the limen insulae.

OBSERVATIONS

A retrospective analysis of patients who had undergone clip ligation of MCA aneurysms located at the limen recess at a single institute was performed. Patients with angiographic and clinical follow-up data were considered eligible. A total of 11 aneurysms (4 ruptured and 7 unruptured aneurysms) in 11 patients were evaluated. Postoperative ischemic lesions were observed on images obtained within 1 week after surgery in 5 (45.5%) patients who had undergone partial resection of the limen insulae, although none of them presented with neurological deterioration.

LESSONS

Partial resection of limen insulae may be feasible to avoid severe ischemic complications following clip ligation of M1 aneurysms embedded in the limen recess.

Superb Microvascular Imaging Ultrasound for Cervical Carotid Artery Stenosis for Prediction of the Development of Microembolic Signals on Transcranial Doppler during Carotid Exposure in Endarterectomy

Introduction

During exposure of the carotid arteries, embolism from the surgical site is recognized as a primary cause of neurological deficits or new cerebral ischemic lesions following carotid endarterectomy (CEA), and associations have been reported between histological neovascularization in the carotid plaque and both plaque vulnerability and the development of artery-to-artery embolism. Superb microvascular imaging (SMI) enables accurate visualization of neovessels in the carotid plaque without the use of intravenous contrast. This study aimed to determine whether preoperative SMI ultrasound for cervical carotid artery stenosis predicts the development of microembolic signals (MES) on transcranial Doppler (TCD) during exposure of the carotid arteries in CEA.

Methods

Preoperative cervical carotid artery SMI ultrasound followed by CEA under TCD monitoring of MES in the ipsilateral middle cerebral artery was conducted in 70 patients previously diagnosed with internal carotid artery stenosis (defined as ≥70%). First, observers visually identified intraplaque microvascular flow (IMVF) signals as moving enhancements located near the surface of the carotid plaque within the plaque on SMI ultrasonograms. Next, regions of interest (ROI) were manually placed at the identified IMVF signals (or at arbitrary places within the plaque when no IMVF signals were identified within the carotid plaque) and the carotid lumen, and time-intensity curves of the IMVF signal and lumen ROI were generated. Ten heartbeat cycles of both time-intensity curves were segmented into each heartbeat cycle based on gated electrocardiogram findings and averaged with respect to the IMVF signal and lumen ROI. The difference between the maximum and minimum intensities (ID) was calculated based on the averaged IMVF signal (ID_IMVF) and lumen (ID_l) curves. Finally, the ratio of ID_IMVF to ID_l was calculated.

Results

MES during exposure of the carotid arteries were detected in 17 patients (24%). The incidence of identification of IMVF signals was significantly greater in patients with MES (94%) than in those without (57%; p = 0.0067). The ID_IMVF/ID_l ratio was significantly greater in patients with MES (0.108 ± 0.120) than in those without (0.017 ± 0.042; p < 0.0001). The specificity and positive predictive value for the ID_IMVF/ID_l ratio for prediction of the development of MES were significantly higher than those for the identification of IMVF signals. Logistic regression analysis revealed that only the ID_IMVF/ID_l ratio was significantly associated with the development of MES (95% CI 101.1–3,628.9; p = 0.0048).

Conclusion

Preoperative cervical carotid artery SMI ultrasound predicts the development of MES on TCD during exposure of the carotid arteries in CEA.

Diagnostic Accuracy of Screening Arterial Spin-Labeling MRI Using Hadamard Encoding for the Detection of Reduced CBF in Adult Patients with Ischemic Moyamoya Disease

BACKGROUND AND PURPOSE

Adult patients with ischemic Moyamoya disease are advised to undergo selective revascularization surgery based on cerebral hemodynamics. The purpose of this study was to determine the diagnostic accuracy of arterial spin-labeling MR imaging using Hadamard-encoded multiple postlabeling delays for the detection of reduced CBF in such patients.

MATERIALS AND METHODS

Thirty-seven patients underwent brain perfusion SPECT and pseudocontinuous arterial spin-labeling MR imaging using standard postlabeling delay (1525 ms) and Hadamard-encoded multiple postlabeling delays. For Hadamard-encoded multiple postlabeling delays, based on data obtained from the 7 sub-boluses with combinations of different labeling durations and postlabeling delays, CBF corrected by the arterial transit time was calculated on a voxel-by-voxel basis. Using a 3D stereotaxic template, we automatically placed ROIs in the ipsilateral cerebellar hemisphere and 5 MCA territories in the symptomatic cerebral hemisphere; then, the ratio of the MCA to cerebellar ROI was calculated.

RESULTS

The area under the receiver operating characteristic curve for detecting reduced SPECT-CBF ratios (<0.686) was significantly greater for the Hadamard-encoded multiple postlabeling delays-CBF ratios (0.885) than for the standard postlabeling delay-CBF ratios (0.786) (P = .001). The sensitivity and negative predictive value for the Hadamard-encoded multiple postlabeling delays-CBF ratios were 100% (95% confidence interval, 100%-100%) and significantly higher than the sensitivity (95% CI, 44%-80%) and negative predictive value (95% CI, 88%-97%) for the standard postlabeling delay-CBF ratio, respectively.

CONCLUSIONS

ASL MR imaging using Hadamard-encoded multiple postlabeling delays may be applicable as a screening tool because it can detect reduced CBF on brain perfusion SPECT with 100% sensitivity and a 100% negative predictive value in adult patients with ischemic Moyamoya disease.

Development of cerebral microbleeds in patients with cerebral hyperperfusion following carotid endarterectomy and its relation to postoperative cognitive decline

OBJECTIVE

A primary cause of cognitive decline after carotid endarterectomy (CEA) is cerebral injury due to cerebral hyperperfusion. However, the mechanisms of how cerebral hyperperfusion induces cerebral cortex and white matter injury are not known. The presence of cerebral microbleeds (CMBs) on susceptibility-weighted imaging (SWI) is independently associated with a decline in global cognitive function. The purpose of this prospective observational study was to determine whether cerebral hyperperfusion following CEA leads to the development of CMBs and if postoperative cognitive decline is related to these developed CMBs.

METHODS

During the 27-month study period, patients who underwent CEA for ipsilateral internal carotid artery stenosis (≥ 70%) also underwent SWI and neuropsychological testing before and 2 months after surgery, as well as quantitative brain perfusion SPECT prior to and immediately after surgery.

RESULTS

According to quantitative brain perfusion SPECT and SWI before and after surgery, 12 (16%) and 7 (9%) of 75 patients exhibited postoperative cerebral hyperperfusion and increased CMBs in the cerebral hemisphere ipsilateral to surgery, respectively. Cerebral hyperperfusion was associated with an increase in CMBs after surgery (logistic regression analysis, 95% CI 5.08-31.25, p < 0.0001). According to neuropsychological assessments before and after surgery, 10 patients (13%) showed postoperative cognitive decline. Increased CMBs were associated with cognitive decline after surgery (logistic regression analysis, 95% CI 6.80-66.67, p < 0.0001). Among the patients with cerebral hyperperfusion after surgery, the incidence of postoperative cognitive decline was higher in those with increased CMBs (100%) than in those without (20%; p = 0.0101).

CONCLUSIONS

Cerebral hyperperfusion following CEA leads to the development of CMBs, and postoperative cognitive decline is related to these developed CMBs.

Predicting the consistency of intracranial meningiomas using apparent diffusion coefficient maps derived from preoperative diffusion-weighted imaging

OBJECTIVE

The consistency of meningiomas is a critical factor affecting the difficulty of resection, operative complications, and operative time. The apparent diffusion coefficient (ADC) is derived from diffusion-weighted imaging (DWI) and is calculated using two optimized b values. While the results of comparisons between the standard ADC and the consistency of meningiomas vary, the shifted ADC has been reported to be strongly correlated with liver stiffness. The purpose of the present prospective cohort study was to determine whether preoperative standard and shifted ADC maps predict the consistency of intracranial meningiomas.

METHODS

Standard (b values 0 and 1000 sec/mm2) and shifted (b values 200 and 1500 sec/mm2) ADC maps were calculated using preoperative DWI in patients undergoing resection of intracranial meningiomas. Regions of interest (ROIs) were placed within the tumor on standard and shifted ADC maps and registered on the navigation system. Tumor tissue located at the registered ROI was resected through craniotomy, and its stiffness was measured using a durometer. The cutoff point lying closest to the upper left corner of a receiver operating characteristic (ROC) curve was determined for the detection of tumor stiffness such that an ultrasonic aspirator or scissors was always required for resection. Each tumor tissue sample with stiffness greater than or equal to or less than this cutoff point was defined as hard or soft tumor, respectively.

RESULTS

For 76 ROIs obtained from 25 patients studied, significant negative correlations were observed between stiffness and the standard ADC (ρ = -0.465, p < 0.01) and the shifted ADC (ρ = -0.490, p < 0.01). The area under the ROC curve for detecting hard tumor (stiffness ≥ 20.8 kPa) did not differ between the standard ADC (0.820) and the shifted ADC (0.847) (p = 0.39). The positive predictive value (PPV) for the combination of a low standard ADC and a low shifted ADC for detecting hard tumor was 89%. The PPV for the combination of a high standard ADC and a high shifted ADC for detecting soft tumor (stiffness < 20.8 kPa) was 81%.

CONCLUSIONS

A combination of standard and shifted ADC maps derived from preoperative DWI can be used to predict the consistency of intracranial meningiomas.

Improvement in gait function after carotid endarterectomy is associated with postoperative recovery in perfusion and neurotransmitter receptor function in the motor-related cerebral cortex: a 123I-iomazenil SPECT study

OBJECTIVE

Carotid endarterectomy (CEA) often restores cerebral perfusion and neurotransmitter receptor function, which is seen on early and late images, respectively, on brain I-iomazenil single-photon emission computed tomography (SPECT). The reliability of gait-related parameters obtained using a triaxial accelerometer, a portable device for gait assessment, has been confirmed with test-retest measurements. The purpose of the present prospective cohort study was to determine whether improvement in gait function after CEA is associated with postoperative recovery in perfusion and neurotransmitter receptor function in the motor-related cerebral cortex.

METHODS

Gait testing using a triaxial accelerometer was performed preoperatively and 6 months postoperatively in 64 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≥70%). I-iomazenil SPECT was also performed with scanning within 30 min (early images) and at 180 min (late images) after tracer administration before and after surgery. SPECT data were analyzed using a three-dimensional stereotactic surface projection, and motor (Brodmann 4) and premotor (Brodmann 6) cortexes in each hemisphere were combined and defined as the motor-related cortex.

RESULTS

Based on preoperative and postoperative gait testing, seven patients (11%) showed postoperative improved gait. Logistic regression analysis revealed that postoperative increase in I-iomazenil uptake in the motor-related cortex ipsilateral to surgery on early [95% confidence interval (CI), 4.32-365.21; P = 0.0477) or late (95% CI, 9.45-1572.57; P = 0.0173) images was an independent predictor of postoperative improved gait.

CONCLUSIONS

Improvement in gait function after CEA is associated with postoperative recovery in perfusion and neurotransmitter receptor function in the motor-related cerebral cortex.

Feasibility of IVIM parameters from diffusion-weighted imaging at 11.7T MRI for detecting ischemic changes in common carotid artery occlusion rats

This study aimed to investigate whether intravoxel incoherent motion (IVIM) parameters can identify ischemic changes in the rat cerebral cortex using a preclinical ultra-high-field 11.7 Tesla magnetic resonance imaging (11.7TMRI) scanner. In nine female Wistar rats (eight weeks old), diffusion-weighted imaging (DWI) for IVIM analysis was successfully performed before (Pre) and after unilateral (UCCAO) and bilateral (BCCAO) common carotid artery occlusion. From the acquired DWI signals averaged in six regions of interest (ROI) placed on the cortex, volume fraction of perfusion compartment (F), pseudo diffusion coefficient (D*), F × D* and apparent diffusion coefficient (ADC) were determined as IVIM parameters in the following three DWI signal models: the bi-exponential, kurtosis, and tri-exponential model. For a subgroup analysis, four rats that survived two weeks after BCCAO were assigned to the long survival (LS) group, whereas the non-LS group consisted of the remaining five animals. Each IVIM parameter change among three phases (Pre, UCCAO and BCCAO) was statistically examined in each ROI. Then, the change in each rat group was also examined for subgroup analysis. All three models were able to identify cerebral ischemic change and damage as IVIM parameter change among three phases. Furthermore, the kurtosis model could identify the parameter changes in more regions than the other two models. In the subgroup analysis with the kurtosis model, ADC in non-LS group significantly decreased between UCCAO and BCCAO but not in LS group. IVIM parameters at 11.7TMRI may help us to detect the subtle ischemic change; in particular, with the kurtosis model.

Acetazolamide-Loaded Dynamic 7T MR Quantitative Susceptibility Mapping in Major Cerebral Artery Steno-Occlusive Disease: Comparison with PET

BACKGROUND AND PURPOSE

Dynamic changes in cerebrovascular reactivity after acetazolamide administration vary markedly among patients with major cerebral arterial steno-occlusive disease. MR quantitative susceptibility mapping can dynamically quantify the cerebral magnetic susceptibility. The purpose of this study was to determine whether dynamic changes in susceptibility after administration of acetazolamide on 7T quantitative susceptibility mapping are associated with pre-existing states of CBV and the cerebral metabolic rate of oxygen in the cerebral hemispheres with major cerebral arterial steno-occlusive disease.

MATERIALS AND METHODS

Sixty-five patients underwent 7T MR imaging at baseline and at 5, 10, 15, and 20 minutes after acetazolamide administration. Differences between the susceptibility of venous structures and surrounding brain tissue were calculated in the quantitative susceptibility mapping images. Susceptibility differences at 5, 10, 15, and 20 minutes after acetazolamide administration relative to baseline were calculated in 97 cerebral hemispheres with major cerebral arterial steno-occlusive disease. CBV and the cerebral metabolic rate of oxygen were also calculated using ¹⁵O-gas PET in the resting state.

RESULTS

Dynamic changes of susceptibility after acetazolamide administration were classified into 3 patterns: abnormally increasing 5 or 10 minutes after acetazolamide administration; abnormally decreasing within 20 minutes after acetazolamide administration; and remaining unchanged after acetazolamide administration. CBV was significantly greater in the first pattern than in the latter 2. The cerebral metabolic rate of oxygen differed significantly in descending order from the first to middle to last pattern.

CONCLUSIONS

Dynamic changes of susceptibility after acetazolamide administration on 7T MR quantitative susceptibility mapping are associated with pre-existing states of CBV and the cerebral metabolic rate of oxygen in major cerebral arterial steno-occlusive disease.

The Coefficient of Variation of Step Time Can Overestimate Gait Abnormality: Test-Retest Reliability of Gait-Related Parameters Obtained with a Tri-Axial Accelerometer in Healthy Subjects

The aim of this study was to investigate whether variation in gait-related parameters among healthy participants could help detect gait abnormalities. In total, 36 participants (21 men, 15 women; mean age, 35.7 ± 9.9 years) performed a 10-m walk six times while wearing a tri-axial accelerometer fixed at the L3 level. A second walk was performed ≥1 month after the first (mean interval, 49.6 ± 7.6 days). From each 10-m data set, the following nine gait-related parameters were automatically calculated: assessment time, number of steps, stride time, cadence, ground force reaction, step time, coefficient of variation (CV) of step time, velocity, and step length. Six repeated measurement values were averaged for each gait parameter. In addition, for each gait parameter, the difference between the first and second assessments was statistically examined, and the intraclass correlation coefficient (ICC) was calculated with the level of significance set at p < 0.05. Only the CV of step time showed a significant difference between the first and second assessments (p = 0.0188). The CV of step time also showed the lowest ICC, at <0.50 (0.425), among all parameters. Test-retest results of gait assessment using a tri-axial accelerometer showed sufficient reproducibility in terms of the clinical evaluation of all parameters except the CV of step time.

Reduction in amyloid β deposition on 18F-florbetapir positron emission tomography with correction of cerebral hypoperfusion after endarterectomy for carotid stenosis

The process of amyloid β (Aβ) deposition in sporadic Alzheimer's disease remains unclear. However, hypoperfusion due to vascular pathology may precede Aβ deposition, as suggested by data from animal models and autopsy tissue from Alzheimer's disease patients. In this exploratory study, we examined the hypotheses that chronic cerebral hypoperfusion due to severe atherosclerotic stenosis of the internal carotid artery (ICA) increases Aβ deposition in the affected cerebral hemisphere and that correction of cerebral hypoperfusion after carotid endarterectomy (CEA) in such patients reduces Aβ deposition. Four patients with cerebral hemispheric hypoperfusion due to unilateral ICA stenosis (≥80%) and without episodes of carotid territory ischemic symptoms or infarcts in the bilateral cerebral hemispheres underwent brain perfusion single-photon emission computed tomography (SPECT) and Aβ deposition positron emission tomography (PET) with ¹⁸F-florbetapir before and after CEA. The asymmetry ratio of the radioactive counts in the affected cerebral hemisphere relative to that in the contralateral cerebral hemisphere was calculated on SPECT and PET images. In all four patients, the SPECT-perfusion asymmetry ratio was ≤0.81 before surgery and ≥0.90 after surgery. The PET-Aβ deposition asymmetry ratio ranged from 0.98 to 1.01 before surgery. The value in two patients remained at ≥0.97 after surgery, and in the other two patients, the value decreased to ≤0.91 after surgery. These findings suggested that chronic cerebral hypoperfusion due to severe atherosclerotic stenosis of the ICA does not increase Aβ deposition in the affected cerebral hemisphere, but correction of cerebral hypoperfusion after CEA often reduces Aβ deposition.

Wall Shear Stress and T1 Contrast Ratio Are Associated With Embolic Signals During Carotid Exposure in Endarterectomy

Supplemental Digital Content is available in the text.

Background and Purpose—

The frictional force because of blood flow may dislodge masses present on the surface of a plaque. Such frictional force is calculated as wall shear stress (WSS) using computational fluid dynamics. The aims of the present study were to determine whether, in addition to carotid plaque intensity on T1-weighted magnetic resonance (MR) imaging, WSS calculated using computational fluid dynamics analysis for carotid arteries is associated with development of an embolism during exposure of carotid arteries during carotid endarterectomy.

Methods—

One hundred patients with internal carotid artery stenosis (≥70%) underwent carotid plaque imaging with MR, and 54 patients with a vulnerable plaque (intraplaque hemorrhage or lipid/necrotic core) displayed as a high-intensity lesion underwent additional cervical 3-dimensional MR angiography. The maximum value of WSS within the most severe stenotic segment of the internal carotid artery was calculated using MR angiography. Transcranial Doppler monitoring of microembolic signals (MES) in the ipsilateral middle cerebral artery was performed during carotid endarterectomy.

Results—

Although none of the 46 patients with a nonvulnerable carotid plaque had MES during exposure of carotid arteries, 24 of the 54 patients with a vulnerable carotid plaque (44%) had MES. Logistic regression analysis showed that higher plaque intensity (P=0.0107) and higher WSS (P=0.0029) were significantly associated with the development of MES. When both cutoff points of plaque intensity and WSS in the receiver operating characteristic curves for predicting development of MES were combined, specificity (from 63% to 93%) and positive predictive value (from 66% to 90%) became greater than those for plaque intensity alone.

Conclusions—

In addition to carotid plaque intensity on T1-weighted MR imaging, WSS calculated using computational fluid dynamics analysis for carotid arteries is associated with development of an embolism during exposure of carotid arteries during carotid endarterectomy.

Adverse effects of pre-existing cerebral small vessel disease on cognitive improvement after carotid endarterectomy

BACKGROUND

Although patients with improved cognition after carotid endarterectomy usually exhibit postoperative restoration of cerebral blood flow, less than half of patients with such cerebral blood flow change have postoperatively improved cognition. Cerebral small vessel disease on magnetic resonance imaging is associated with irreversible cognitive impairment.

AIMS

The purpose of the present prospective study was to determine whether pre-existing cerebral small vessel disease affects cognitive improvement after carotid endarterectomy.

METHODS

Brain MR imaging was performed preoperatively, and the number or grade of each cerebral small vessel disease was determined in 80 patients undergoing carotid endarterectomy for ipsilateral internal carotid artery stenosis (≥70%). The volume of white matter hyperintensities relative to the intracranial volume was also calculated. Brain perfusion single-photon emission computed tomography and neuropsychological testing were performed preoperatively and two months postoperatively. Based on these data, a postoperative increase in cerebral blood flow and postoperative improved cognition, respectively, were determined.

RESULTS

Logistic regression analysis using the sequential backward elimination approach revealed that a postoperative increase in cerebral blood flow (95% confidence interval [CI], 10.74-3730.00; P = 0.0004) and the relative volume of white matter hyperintensities (95% CI, 0.01-0.63; P = 0.0314) were significantly associated with postoperative improved cognition. Although eight of nine patients with postoperative improved cognition exhibited both a relative volume of white matter hyperintensities <0.65% and a postoperative increase in cerebral blood flow, none of patients with a relative volume of white matter hyperintensities ≥0.65% had postoperative improved cognition regardless of any postoperative change in cerebral blood flow.

CONCLUSION

Pre-existing cerebral white matter hyperintensities on magnetic resonance imaging adversely affect cognitive improvement after carotid endarterectomy.

Simple assessment of the localization of posterior communicating artery aneurysms to the anterior petroclinoid ligament

The microsurgical management of posterior communicating artery (PCoA) aneurysms can be modified depending on their localization, with respect to the tentorial edge consisting of the anterior petroclinoid ligament (APCL). However, the imaging of APCL has been impractical to date. In this study, we evaluated a simple method for assessing the relationship between PCoA aneurysms and APCL, using three-dimensional computed tomographic angiography (3D-CTA). We retrospectively reviewed all surgically treated cases of PCoA aneurysms via the pterional approach in our institute from May 2013 to August 2018. To predict the localization of the aneurysms, three anatomical lines were drawn on non-subtracted volumetric 3D-CTA as follows: 1. the apex of the anterior clinoid process to the posterior border of the trigeminal depression of the petrosal bone (AACP-PBTD); 2. AACP to the superior edge of the arcuate eminence (AACP-SEAE); 3. the base of the ACP to the superior edge of the arcuate eminence (BACP-SEAE). The relative location of each line to the PCoA aneurysms was compared with actual intraoperative findings. Fifty-six aneurysms were included. The sensitivity, specificity, and positive and negative predictive values of the superior localization of the aneurysm of the AACP-TDPB line were 93.8%, 40.0%, 38.5%, and 94.1%, respectively. Those of the AACP-SEAE line were 93.8%, 42.5%, 39.5, and 94.4%, respectively. In contrast, those of the BACP-SEAE line were 93.8%, 97.5%, 93.8%, and 97.5%, respectively. The BACP-SEAE line is a simple and practical landmark in predicting APCL.

Impact of the Intracranial Course of Internal Carotid Artery on Optimal Surgical Approach for Posterior Communicating Artery Aneurysms

BACKGROUND

The anterior temporal approach (ATA) has been reported as suitable for surgical clipping of posteriorly projecting internal carotid artery (ICA) aneurysms. As the ICA follows a variable course, tortuosity of the ICA may affect visualization of the aneurysm. The aim of this study was to investigate the impact of the intracranial course of the ICA and aneurysm projection on surgical approach.

METHODS

Consecutive patients with posterior communicating artery aneurysms treated with clipping at our hospital between May 2015 and April 2018 were retrospectively reviewed. When the transsylvian approach (TSA) could not achieve adequate exposure of the aneurysm, the ATA was subsequently performed. Distance between the ICA and the anterior and posterior clinoid line, angle between the midline and the C1 segment of the ICA, and aneurysm projection were compared between ATA and TSA groups.

RESULTS

Of 52 patients (40 ruptured, 12 unruptured), 12 were in the ATA group, and 40 were in the TSA group. Mean ICA-anterior and posterior clinoid distance was significantly shorter in the ATA group than in the TSA group (P = 0.002), and mean midline-C1 angle was significantly larger in the ATA group than in the TSA group (P < 0.0001). The ATA group was associated with a greater frequency of posteriorly projecting aneurysms (12 of 12; 100%) than the TSA group (9 of 40; 22.5%) (P < 0.00001).

CONCLUSIONS

A low-lying, laterally projecting intracranial ICA and posteriorly projecting aneurysm are predictors of the necessity for the ATA in the surgical clipping of posterior communicating artery aneurysms.

Cilostazol may improve cognition better than clopidogrel in non-surgical adult patients with ischemic moyamoya disease: subanalysis of a prospective cohort

OBJECTIVE

Adult patients with ischemic moyamoya disease (MMD) who receive treatment with antiplatelet drugs reportedly show improvements in neuropsychological test scores after around 2 years. The purpose of the present study subanalyzing the same patient cohort used in a previous study was to determine which antiplatelet drug, clopidogrel or cilostazol, results in better improvement of cognitive function among non-surgical adult patients showing ischemic MMD without severe hemodynamic compromise.

METHODS

Sixty-six patients without cerebral misery perfusion on ¹⁵O gas positron emission tomography were treated with pharmacotherapy alone. Patients ≥50 years old and <50 years old initially received clopidogrel and cilostazol, respectively. Any patient suffering side effects of the antiplatelet drug switched to the other antiplatelet drug. Neuropsychological tests were performed at study entry and at the end of the 2-year follow-up, and differences in each neuropsychological test score between the two time points (second test score - first test score) were calculated and defined as Δ scores.

RESULTS

Among the five neuropsychological tests, Δ scores for two tests were significantly greater in patients treated with cilostazol (n = 36) than in those treated with clopidogrel (n = 30), and Δ scores of the remaining three tests did not differ between patient groups. Based on Δ scores, 15 patients (23%) were defined as showing interval cognitive improvement. On multivariate analysis, cilostazol administration (95% confidence interval, 1.19-193.98; P = 0.0361) represented an independent predictor of interval cognitive improvement.

CONCLUSIONS

Cilostazol may improve cognition better than clopidogrel in non-surgical adult patients with ischemic MMD.

Reduced Hypoxic Tissue and Cognitive Improvement after Revascularization Surgery for Chronic Cerebral Ischemia

BACKGROUND

Hypoxic but viable neural tissue is seen on 1-(2-18F-fluoro-1-[hydroxymethyl]ethoxy) methyl-2-nitroimidazole (18F-FRP170) positron emission tomography (PET) in patients with chronic cerebral ischemia with a combination of misery perfusion and moderately reduced oxygen metabolism. Cognitive function sometimes improves after revascularization surgery in patients with chronic cerebral ischemia.

OBJECTIVES

We used brain perfusion single-photon emission computed tomography (SPECT) and 18F-FRP170 PET to determine whether hypoxic tissue was reduced following the restoration of cerebral perfusion after carotid endarterectomy (CEA) in patients with severe stenosis of the cervical internal carotid artery (ICA) and whether the reduction in hypoxic tissue was associated with cognitive improvement.

METHOD

Eighteen patients with abnormally reduced cerebral blood flow (CBF) in the affected cerebral hemispheres on preoperative brain perfusion SPECT -underwent CEA. They underwent 18F-FRP170 PET and neuropsychological tests preoperatively and 6 months postoperatively. Brain perfusion SPECT was also performed 6 months postoperatively. Regions of interest were placed in the bilateral middle cerebral artery territories on SPECT and PET images, and the ratio of values in the affected versus contralateral hemispheres was calculated.

RESULTS

The CBF ratio (p = 0.0006) and 18F-FRP170 ratio (p = 0.0084) were significantly increased and reduced, respectively, after surgery compared to the corresponding ratios before surgery. The difference in the 18F-FRP170 ratio (postoperative - preoperative value) was negatively correlated with the difference in the CBF ratio (ρ = -0.695; p = 0.0009). The difference in the 18F-FRP170 ratio was significantly lower in patients with postoperative improved cognition compared to that in those without (p = 0.0007). The area under the receiver operating characteristics curve for the difference in the 18F-FRP170 ratio for detecting postoperative improved cognition was significantly greater than that for the difference in the CBF ratio (difference between areas, 0.278; p = 0.0248).

CONCLUSIONS

Hypoxic tissue is reduced following the restoration of cerebral perfusion with revascularization surgery in patients with severe atherosclerotic stenosis of the cervical ICA. The reduction in hypoxic tissue is associated with cognitive improvement in such patients.

Comparison of Effects between Clopidogrel and Cilostazol on Cerebral Perfusion in Nonsurgical Adult Patients with Symptomatically Ischemic Moyamoya Disease: Subanalysis of a Prospective Cohort

BACKGROUND AND PURPOSE

Adult patients with symptomatically ischemic moyamoya disease (MMD) initially undergo medical treatment alone including antiplatelet drugs when symptomatic cerebral hemispheres do not exhibit hemodynamic compromise. The purpose of the present study subanalyzing the same patient cohort used in a previous study was to determine which antiplatelet drug, clopidogrel or cilostazol, provides better improvement of cerebral perfusion in such patients.

METHODS

All patients without cerebral misery perfusion on ¹⁵O gas positron emission tomography (PET) did not undergo revascularization surgery and were treated with medication alone, including antiplatelet therapy. Patients ≥50years and <50years initially received clopidogrel and cilostazol, respectively. When a patient suffered side effects of an antiplatelet drug, they were switched to the other antiplatelet drug. Cerebral blood flow (CBF) in the symptomatic hemisphere was measured at inclusion and at 2years after inclusion using ¹⁵O gas PET.

RESULTS

Of 68 patients, 31 and 38 were treated with clopidogrel and cilostazol, respectively, for 2years after inclusion. For patients treated with clopidogrel, CBF did not differ between first and second PET. For patients treated with cilostazol, CBF was significantly greater in the second PET than in the first PET. On multivariate analysis, cilostazol administration was an independent predictor of CBF improvement in the symptomatic hemisphere (95% confidence interval, 1.34-139.20; P =.0271).

CONCLUSIONS

Cilostazol improves cerebral perfusion better than clopidogrel in adult patients with symptomatically ischemic MMD not accompanied by misery perfusion.