Type-2 Diabetes Alters Hippocampal Neural Oscillations and Disrupts Synchrony between the Hippocampus and Cortex.

Type 2 diabetes mellitus (T2DM) increases the risk of neurological diseases, yet how brain oscillations change as age and T2DM interact is not well characterized. To delineate the age and diabetic effect on neurophysiology, we recorded local field potentials with multichannel electrodes spanning the somatosensory cortex and hippocampus (HPC) under urethane anesthesia in diabetic and normoglycemic control mice, at 200 and 400 days of age. We analyzed the signal power of brain oscillations, brain state, sharp wave associate ripples (SPW-Rs), and functional connectivity between the cortex and HPC. We found that while both age and T2DM were correlated with a breakdown in long-range functional connectivity and reduced neurogenesis in the dentate gyrus and subventricular zone, T2DM further slowed brain oscillations and reduced theta-gamma coupling. Age and T2DM also prolonged the duration of SPW-Rs and increased gamma power during SPW-R phase. Our results have identified potential electrophysiological substrates of hippocampal changes associated with T2DM and age. The perturbed brain oscillation features and diminished neurogenesis may underlie T2DM-accelerated cognitive impairment.

Type-2 diabetes alters hippocampal neural oscillations and disrupts synchrony between hippocampus and cortex.

Type 2 diabetes mellitus (T2DM) increases the risk of neurological diseases, yet how brain oscillations change as age and T2DM interact is not well characterized. To delineate the age and diabetic effect on neurophysiology, we recorded local field potentials with multichannel electrodes spanning the somatosensory cortex and hippocampus (HPC) under urethane anesthesia in diabetic and normoglycemic control mice, at 200 and 400 days of age. We analyzed the signal power of brain oscillations, brain state, sharp wave associate ripples (SPW-Rs), and functional connectivity between the cortex and HPC. We found that while both age and T2DM were correlated with a breakdown in long-range functional connectivity and reduced neurogenesis in the dentate gyrus and subventricular zone, T2DM further slowed brain oscillations and reduced theta-gamma coupling. Age and T2DM also prolonged the duration of SPW-Rs and increased gamma power during SPW-R phase. Our results have identified potential electrophysiological substrates of hippocampal changes associated with T2DM and age. The perturbed brain oscillation features and diminished neurogenesis may underlie T2DM-accelerated cognitive impairment.

Erratum to "Carotid computed tomography angiography after cobalt-based alloy carotid artery stenting using ultra-high-resolution computed tomography with model-based iterative reconstruction" [Radiol Case Rep 2021;16:3721-8].

[This corrects the article DOI: 10.1016/j.radcr.2021.09.003.].

Marked Reduction of Cerebral Vasospasm with Intrathecal Urokinase Infusion Therapy after Endovascular Coil Embolization of the Aneurysmal Subarachnoid Hemorrhage: A Case Series.

Delayed cerebral vasospasms after subarachnoid hemorrhage (SAH) are a risk factor for poor prognosis after successful treatment of ruptured intracranial aneurysms. Different strategies to remove clots from the subarachnoid space and prevent vasospasms have different outcomes. Intrathecal urokinase infusion therapy combined with endovascular treatment (EVT) can reduce the incidence of symptomatic vasospasms. To analyze the relationship between symptomatic vasospasms and residual SAHs after urokinase infusion therapy, we retrospectively reviewed the records of 348 consecutive patients managed with EVT and intrathecal urokinase infusion therapy for aneurysmal SAH at our institution between 2010 and 2021. Among them, 163 patients met the study criteria and were classified into two groups according to the presence of residual SAH in the cisterns, Sylvian fissures, and frontal interhemispheric fissure. The incidence of symptomatic vasospasms and the clinical outcomes were assessed. In total, eight (5.0%) patients developed symptomatic vasospasms. Patients with symptomatic vasospasms had a significantly higher incidence of residual SAH in the Sylvian or frontal interhemispheric fissures than those without (P <.0001). No patient with SAHs resolved by urokinase infusion therapy developed symptomatic vasospasms. However, the two groups did not differ significantly in terms of modified Rankin scale scores at discharge. Treatment with intrathecal urokinase infusion after EVT for aneurysmal SAH can substantially reduce the risk of clinically evident vasospasms.

Remodeling of the Neurovascular Unit Following Cerebral Ischemia and Hemorrhage.

Formulated as a group effort of the stroke community, the transforming concept of the neurovascular unit (NVU) depicts the structural and functional relationship between brain cells and the vascular structure. Composed of both neural and vascular elements, the NVU forms the blood-brain barrier that regulates cerebral blood flow to meet the oxygen demand of the brain in normal physiology and maintain brain homeostasis. Conversely, the dysregulation and dysfunction of the NVU is an essential pathological feature that underlies neurological disorders spanning from chronic neurodegeneration to acute cerebrovascular events such as ischemic stroke and cerebral hemorrhage, which were the focus of this review. We also discussed how common vascular risk factors of stroke predispose the NVU to pathological changes. We synthesized existing literature and first provided an overview of the basic structure and function of NVU, followed by knowledge of how these components remodel in response to ischemic stroke and brain hemorrhage. A greater understanding of the NVU dysfunction and remodeling will enable the design of targeted therapies and provide a valuable foundation for relevant research in this area.

Sexual dimorphism in immune cell responses following stroke.

Recent bodies of work in regard to stroke have revealed significant sex differences in terms of risk and outcome. While differences in sex hormones have been the focus of earlier research, the reasons for these differences are much more complex and require further identification. This review covers differences in sex related immune responses with a focus on differences in immune cell composition and function. While females are more susceptible to immune related diseases, they seem to have better outcomes from stroke at the experimental level with reduced pro-inflammatory responses. However, at the clinical level, the picture is much more complex with worse neurological outcomes from stroke. While the use of exogenous sex steroids can replicate some of these findings, it is apparent that many other factors are involved in the modulation of immune responses. As a result, more research is needed to better understand these differences and identify appropriate interventions and risk modification.

Pathological changes of brain oscillations following ischemic stroke.

Brain oscillations recorded in the extracellular space are among the most important aspects of neurophysiology data reflecting the activity and function of neurons in a population or a network. The signal strength and patterns of brain oscillations can be powerful biomarkers used for disease detection and prediction of the recovery of function. Electrophysiological signals can also serve as an index for many cutting-edge technologies aiming to interface between the nervous system and neuroprosthetic devices and to monitor the efficacy of boosting neural activity. In this review, we provided an overview of the basic knowledge regarding local field potential, electro- or magneto- encephalography signals, and their biological relevance, followed by a summary of the findings reported in various clinical and experimental stroke studies. We reviewed evidence of stroke-induced changes in hippocampal oscillations and disruption of communication between brain networks as potential mechanisms underlying post-stroke cognitive dysfunction. We also discussed the promise of brain stimulation in promoting post stroke functional recovery via restoring neural activity and enhancing brain plasticity.

Comparison between ultra-high-resolution computed tomographic angiography and conventional computed tomographic angiography in the visualization of the subcallosal artery.

BACKGROUND: The subcallosal artery (ScA) is a single dominant artery arising from the anterior communicating artery. Its injury causes amnesia and cognitive disturbance. The conventional computed tomographic angiography (C-CTA) is a common evaluation method of the intracranial artery. However, to image tinny perforating arteries such as the ScA is technically demanding for C-CTA. The purpose of this study is to investigate whether the ultra-high-resolution CTA (UHR-CTA) could image the ScA better than C-CTA. UHR-CTA became available in clinical practice in 2017. Its novel features are the improvement of the detector system and a small X-ray focus. METHODS: Between April 2019 and May 2020, 77 and 49 patients who underwent intracranial UHR-CTA and C-CTA, respectively, were enrolled in this study. Two board-certified neurosurgeons participated as observers to identify the ScA based on UHR-CTA and C-CTA images. RESULTS: UHR-CTA and C-CTA detected the ScA in 56-58% and 30-40% of the patients, respectively. In visualization of the ScA, UHR-CTA was better than C-CTA (P < 0.05, Fisher's exact test). Between the two observers, the Cohen's kappa coefficient was 0.77 for UHR-CTA and 0.78 for C-CTA. CONCLUSIONS: UHR-CTA is a simple and accessible method to evaluate intracranial vasculature. Visualization of the ScA with UHR-CTA was better than that with C-CTA. The high quality of UHR-CTA could provide useful information in the neurosurgery field.

Carotid computed tomography angiography after cobalt-based alloy carotid artery stenting using ultra-high-resolution computed tomography with model-based iterative reconstruction.

In conventional carotid computed tomographic angiography, the artifacts of the stent vary depending on the structure and characteristics of the alloy type. Cobalt-based alloy stents have been reported to exhibit high artifacts, and accurate evaluation of the internal lumen can be difficult. Recently, ultra-high-resolution computed tomography scanner systems have become available for clinical practice. The primary features of this computed tomography scanner are a 0.25-mm detector row width and a 1024 × 1024 matrix. We report a case-series of carotid artery stenting using a cobalt-based alloy stent scanned by an ultra-high-resolution computed tomography scanner system and model-based iterative reconstruction. We also report that the combination of the ultra-high-resolution computed tomography scanner system with model-based iterative reconstruction would be useful to evaluate vessel patency after placement of a cobalt-based alloy stent.

Deep Learning-Based Functional Independence Measure Score Prediction After Stroke in Kaifukuki (Convalescent) Rehabilitation Ward Annexed to Acute Care Hospital.

Introduction Prediction models of functional independent measure (FIM) score after kaifukuki (convalescent) rehabilitation ward (KRW) are needed to decide the treatment strategies and save medical resources. Statistical models were reported, but their accuracies were not satisfactory. We made such prediction models using the deep learning (DL) framework, Prediction One (Sony Network Communications Inc., Tokyo, Japan). Methods Of the 559 consecutive stroke patients, 122 patients were transferred to our KRW. We divided our 122 patients' data randomly into halves of training and validation datasets. Prediction One made three prediction models from the training dataset using (1) variables at the acute care ward admission, (2) those at the KRW admission, and (3) those combined (1) and (2). The models' determination coefficients (R2), correlation coefficients (rs), and residuals were calculated using the validation dataset. Results Of the 122 patients, the median age was 71, length of stay (LOS) in acute care ward 23 (17-30) days, LOS in KRW 53 days, total FIM scores at the admission of KRW 85, those at discharge 108. The mean FIM gain and FIM efficiency were 19 and 0.417. All patients were discharged home. Model (1), (2), and (3)'s R2 were 0.794, 0.970, and 0.972. Their mean residuals between the predicted and actual total FIM scores were -1.56±24.6, -4.49±17.1, and -2.69±15.7. Conclusion Our FIM gain and efficiency were better than national averages of FIM gain 17.1 and FIM efficiency 0.187. We made DL-based total FIM score prediction models, and their accuracies were superior to those of previous statistically calculated ones. The DL-based FIM score prediction models would save medical costs and perform efficient stroke and rehabilitation medicine.

Chronic subdural hematoma in patients over 65 years old: Results of using a postoperative cognitive evaluation to determine whether to permit return to driving.

BACKGROUND: Chronic subdural hematoma (CSDH) is usually associated with good recovery with burr hole irrigation and postoperative drainage under local anesthesia. In Japan, traffic accidents by the elderly drivers over 65 years old are severely increasing, and there is no consensus on whether or not to return to driving after CSDH treatment. We perform a postoperative cognitive assessment. We retrospectively investigated the return-to-driving rate and associated factors. METHODS: Of the 45 patients over 65 y.o. and who had usually driven, 30 patients wished to drive again. We performed tests composed of Mini-Mental State Examination (MMSE), line cancellation and line bisection task, Kohs block design test, trail making test (TMT)-A and B, Kana-hiroi test, Rey-Osterrieth complex figure test, and behavioral assessment of the dysexecutive syndrome, in order. When all tests' scores were better than the cutoff values, we let patients drive again. When some of the scores were worse than the cutoff values, we reevaluated the patients at the outpatient every month. If the patients' scores could not improve at the outpatient, we recommended them to stop driving. RESULTS: Nineteen of 30 patients could return to driving. Worse MMSE, Kohs block design test, TMT-A, TMT-B scores, higher age, dementia, or consciousness disturbance as chief complaints were associated with driving disability. CONCLUSION: CSDH is known as treatable dementia. However, we should perform an objective cognitive assessment before discharge because only 63% of the patients over 65 y.o. who wished to drive could return to driving.

Standard values for temporal muscle thickness in the Japanese population who undergo brain check-up by magnetic resonance imaging.

BACKGROUND: Skeletal muscle mass is an important factor for various diseases' outcomes. The psoas muscle cross-sectional area on the abdominal computed tomography (CT), gait speed, and handgrip strength is used to measure it. However, it is difficult to measure the neurological patients' muscle mass or function because (1) we do not perform abdominal CT. (2) Such patients have impaired consciousness, gait disturbance, paresis, and need of rest. Temporal muscle thickness (TMT) on magnetic resonance imaging (MRI) is now attractive for skeletal muscle volume indicator, but the reference values are not established. We herein investigated the standard value of the Japanese TMT using the brain check-up database by MRI. METHODS: We retrospectively investigated 360 Japanese individuals from two institutions between 2017 and 2019. We measured TMT on the T1-weighted images in the previously reported way. The associations between TMT and other variables were analyzed. RESULTS: TMT of 214 women and 146 men, ranging from 35 to 84 years old, was investigated. TMT ranged from 3.69 to 16.90 mm. Mean TMT values were significantly higher in men compared to women except for the over 70-year-old cohort. TMT was correlated to weight and body mass index in both sexes. CONCLUSION: This is the first retrospective study on the standard TMT values from the Japanese brain check-up database. Our results were just reference values, but these would be useful for further investigation in other neurosurgical and neurological diseases regarding muscle volume or sarcopenia.

Preliminary development of a prediction model for daily stroke occurrences based on meteorological and calendar information using deep learning framework (Prediction One; Sony Network Communications Inc., Japan).

BACKGROUND: Chronologically meteorological and calendar factors were risks of stroke occurrence. However, the prediction of stroke occurrences is difficult depending on only meteorological and calendar factors. We tried to make prediction models for stroke occurrences using deep learning (DL) software, Prediction One (Sony Network Communications Inc., Tokyo, Japan), with those variables. METHODS: We retrospectively investigated the daily stroke occurrences between 2017 and 2019. We used Prediction One software to make the prediction models for daily stroke occurrences (present or absent) using 221 chronologically meteorological and calendar factors. We made a prediction models from the 3-year dataset and evaluated their accuracies using the internal cross-validation. Areas under the curves (AUCs) of receiver operating characteristic curves were used as accuracies. RESULTS: The 371 cerebral infarction (CI), 184 intracerebral hemorrhage (ICH), and 53 subarachnoid hemorrhage patients were included in the study. The AUCs of the several DL-based prediction models for all stroke occurrences were 0.532-0.757. Those for CI were 0.600-0.782. Those for ICH were 0.714-0.988. CONCLUSION: Our preliminary results suggested a probability of the DL-based prediction models for stroke occurrence only by meteorological and calendar factors. In the future, by synchronizing a variety of medical information among the electronic medical records and personal smartphones as well as integrating the physical activities or meteorological conditions in real time, the prediction of stroke occurrence could be performed with high accuracy, to save medical resources, to have patients care for themselves, and to perform efficient medicine.

Basilar artery dissection with rupture 6 years after accidental detection: A case report.

BACKGROUND: Chronic basilar artery dissection (BAD) is a rare pathology, and only a few reports have been mentioned in the literature. The imaging features of chronic BAD, especially those that develop into a subarachnoid hemorrhage (SAH), are unknown. CASE DESCRIPTION: We report a unique case of a chronic BAD with a split intimal flap that developed into an SAH. A 74-year-old man was diagnosed with BAD. After considering all treatment options, conservative treatment was selected for the patient. We continued imaging follow-up of the patient in our outpatient clinic once a year. The BA gradually dilated and the internal flap split. The patient and his family refused surgical treatment; therefore, conservative treatment was continued. Six years and 2 months from the first diagnosis, he developed a massive SAH and died. CONCLUSION: In the case of this patient, the weakened condition of the internal elastic lamina may have caused dissection of the intimal flap between the intima and media. Furthermore, the dissection may have developed and connected the true lumen to the pseudolumen and induced BA rupture. Thereby, split of the internal flap could be a risk factor for rupture in chronic BAD.

Usefulness of 3 Tesla Ultrashort Echo Time Magnetic Resonance Angiography (UTE-MRA, SILENT-MRA) for Evaluation of the Mother Vessel after Cerebral Aneurysm Clipping: Case Series of 19 Patients.

It is important to assess the cerebral arteries near the clip after cerebral aneurysm clipping. Contrast-enhanced computed tomography angiography has side effects of contrast medium and radiation exposure. Time-of-flight magnetic resonance angiography (TOF-MRA) is a fast and non-invasive method, but clip-induced artifact limits the assessment around the clip. Recently, 3 tesla MRA with ultrashort echo time called SILENT MRA (GE Healthcare Life Sciences, UK) has been reported to have the potential to overcome these disadvantages. We herein present consecutive 19 cerebral aneurysm patients treated by clipping and evaluated using SILENT MRA. The 19 patients (15 women and 4 men) underwent TOF-MRA and SILENT MRA during the same scan session. Two neurosurgeons independently assessed the visibility of the mother vessel at the clipping site in TOF-MRA and SILENT MRA. We also investigated the factors related to visibility in SILENT MRA. All patients' mother vessels were not described in TOF-MRA, and that of 16 patients (84%) were described in SILENT MRA. Overall agreement was 100% in the two neurosurgeons, and the fixed marginal kappa = 1.00 (95% CI: 0.36-1.00). Univariate analysis revealed that larger aneurysm dome and long clip blade length contributed to the visibility of the mother vessel in SILENT MRA. (p = 0.023, 0.007, each). In conclusion, SILENT MRA can be applied for the assessment of the arteries and aneurysm neck remnants near the clip. Using clips with long blade and ligation with its tip would be related to the visibility of the mother vessels in SILENT MRA.

Double-lumen Carotid Plaque Associated with Severe Stenosis Treated with Staged Angioplasty: A Case Report.

Double-lumen carotid plaque is a rare pathological condition, and only few reports about this condition have been recorded in the literature. However, no study has used endovascular therapy (EVT) for the treatment of double-lumen carotid plaque. Herein, we present a unique case of double-lumen carotid plaque associated with severe stenosis that was successfully treated with staged angioplasty (SAP). Moreover, a literature review of its pathology and other treatment options has been conducted. SAP is a two-stage carotid artery stenting (CAS) that can prevent hyperperfusion syndrome after revascularization. In this study, a 62-year-old man developed walking disturbance and left hemiparesis. Magnetic resonance imaging (MRI) revealed ischemic lesions in the watershed area of the right hemisphere and an irregular plaque in the right cervical internal carotid artery (ICA). Ultrasonography showed 84% stenosis in the area and a double lumen distal to the stenosis in the right ICA. Digital subtraction angiography (DSA) revealed a double-lumen plaque with 70% stenosis based on the North American Symptomatic Carotid Endarterectomy Trial criteria. SAP was performed after medication therapy and rehabilitation, and the surgery was uneventful. A double-lumen carotid plaque associated with severe stenosis is a rare condition with a high risk of emboli and stroke. In an unstable lesion, carotid endarterectomy is the first option. However, since the patient in this case was at high risk for general anesthesia, SAP was performed. Hence, if an appropriate device is used, EVT can be a safe treatment strategy for unstable and atypical plaques as in this case.

Three tesla magnetic resonance angiography with ultrashort echo time describes the arteries near the cerebral aneurysm with clip and the peripheral cerebral arteries.

BACKGROUND: The assessment of the clipped cerebral aneurysm and the cerebral arteries after the treatment of subarachnoid hemorrhage (SAH) is important to find aneurysm regrowth or postoperative cerebral vasospasm. Usually, contrast-enhanced computed tomography angiography is performed for the evaluation of the arteries, but it has side effects of contrast medium. Time-of-flight magnetic resonance angiography (MRA) is a fast and non-invasive method, but clip-induced artifact limits assessment of the artery in the vicinity of the clip. 1.5T MRA with ultrashort echo time (UTE) reduces metal artifact, but the obtained image is too rough to evaluate the aneurysm remnant, and the description range is too narrow to assess the cerebral vasospasm. We routinely use SIGNA Pioneer 3.0T (GE Healthcare Life Sciences, Buckinghamshire, England) and perform SILENT SCAN with UTE-MRA for the postoperative assessment of the clipped aneurysm and cerebral arteries for SAH patients treated by clipping. It has better image quality and describes arteries with a wide description range, so it possesses the potential to overcome the disadvantages of 1.5T UTE-MRA. CASE DESCRIPTION: We presented a representative SAH patient who postoperatively underwent 3.0T UTE- MRA after clipping. The artery near the clipped aneurysm was evaluated in detail, and the cerebral arteries were described from the main trunk to the peripheral parts with a wide description range, which enabled the assessment of cerebral vasospasm. CONCLUSION: 3.0T UTE-MRA may be helpful for the usual assessment of the arteries after clipping and cerebral vasospasm in the future.

Parent Artery Occlusion against Dissecting Aneurysm Involving the Proximal Anterior Inferior Cerebellar Artery: Case Report and Literature Review.

Dissecting aneurysms of the anterior inferior cerebellar artery (AICA) are rare. Few reports suggested that coil embolization and parent artery occlusion (PAO) would be valuable treatment options against dissecting AICA aneurysms. We report a case of PAO against dissecting aneurysm involving the proximal AICA and discuss the therapeutics and literature review of this pathology. A 69-year-old woman was referred to our hospital, and neurological examination revealed a semicoma (Hunt and Hess grade IV). Brain computed tomography (CT) established the diagnosis of Fisher group 3 subarachnoid hemorrhage (SAH), CT angiography revealed an extravasation near the clivus, while digital subtraction angiography showed no signs of dissection. Conservative treatment was administered, and repeated angiography on day 13 showed a pseudoaneurysm and false lumen in the left proximal AICA. The patient was in poor health condition, and endovascular therapy (EVT) of the left AICA was performed to minimize invasion. The PAO was successful with no severe ischemic damage to the brainstem and cerebellum. However, the general condition gradually deteriorated, and the patient expired on day 24. Since open surgery for dissecting AICA aneurysm is technically challenging and revascularization procedure is often required, the rapidly developing EVT is a viable alternative. Although preservation of the proximal AICA is usually necessary, PAO without revascularization procedure was performed to avoid the high risk of regrowth and re-rupture of the dissecting aneurysm with respect to the patient's poor health condition. Hence, EVT is a viable option when microsurgery is contraindicated for treating dissecting AICA aneurysms.

Temporal muscle thickness and area with various characteristics data of the patients with aneurysmal subarachnoid hemorrhage who underwent endovascular coiling.

These data present the characteristics of patients with subarachnoid hemorrhage who underwent endovascular coiling. We retrospectively collected data from the medical records of Iwaki City Medical Center including physiological symptoms, laboratory data, radiological data on admission, and modified Rankin Scale scores at 6 months. Our article entitled "Temporal Muscle as an Indicator of Sarcopenia is Independently Associated with Hunt and Kosnik Grade on Admission and the Modified Rankin Scale at 6 Month of Patients with Subarachnoid Hemorrhage Treated by Endovascular Coiling" was based on these data [1]. We previously reported similar small dataset of elderly patients with subarachnoid hemorrhage who underwent surgical clipping [2], [3]. However, remarkably, this is the largest and the first dataset on temporal muscle thickness or area of patients of all ages with subarachnoid hemorrhage who underwent endovascular coiling, not surgical clipping.