Artificial Intelligence Trained by Deep Learning Can Improve Computed Tomography Diagnosis of Nontraumatic Subarachnoid Hemorrhage by Nonspecialists.

Subarachnoid hemorrhage (SAH) is a serious cerebrovascular disease with a high mortality rate and is known as a disease that is hard to diagnose because it may be overlooked by noncontrast computed tomography (NCCT) examinations that are most frequently used for diagnosis. To create a system preventing this oversight of SAH, we trained artificial intelligence (AI) with NCCT images obtained from 419 patients with nontraumatic SAH and 338 healthy subjects and created an AI system capable of diagnosing the presence and location of SAH. Then, we conducted experiments in which five neurosurgery specialists, five nonspecialists, and the AI system interpreted NCCT images obtained from 135 patients with SAH and 196 normal subjects. The AI system was capable of performing a diagnosis of SAH with equal accuracy to that of five neurosurgery specialists, and the accuracy was higher than that of nonspecialists. Furthermore, the diagnostic accuracy of four out of five nonspecialists improved by interpreting NCCT images using the diagnostic results of the AI system as a reference, and the number of oversight cases was significantly reduced by the support of the AI system. This is the first report demonstrating that an AI system improved the diagnostic accuracy of SAH by nonspecialists.

Intracranial and extracranial multiple arterial dissecting aneurysms in rheumatoid arthritis: A case report.

OBJECTIVE: We describe a case of intracranial and extracranial multiple arterial dissecting aneurysms in rheumatoid arthritis (RA). CASE PRESENTATION: A 29-year-old man with a medical history of RA since 18 years of age was admitted to our hospital for vomiting, dysarthria, and conscious disturbance. At 23, he underwent ligation of the left internal carotid artery (ICA) with superficial temporal artery to middle cerebral artery anastomosis because of acute infarct of the left hemisphere caused by arterial dissection of the left ICA. During the current admission, computed tomography (CT) revealed subarachnoid hemorrhage, and digital subtraction angiography (DSA) demonstrated dissecting aneurysms of the left intracranial vertebral artery (VA) and right extracranial VA. We diagnosed him with a ruptured dissecting aneurysm of the left intracranial VA and performed endovascular parent artery occlusion on the left VA. For the right unruptured VA aneurysm, we performed coil embolization simultaneously. At 2 weeks after the endovascular treatment, follow-up DSA revealed that multiple de novo dissecting aneurysms developed on the origin of the left VA and left and right internal thoracic arteries. Those aneurysms were treated with coil embolization. Other remaining aneurysms on the left thyrocervical trunk, right transverse cervical artery, and both common iliac arteries were treated by conservative therapy. While continuing medical treatment for RA, the patient recovered and was discharged to a rehabilitation hospital. CONCLUSION: Considering that RA-induced vasculitis can be a potential risk of vascular complications including multiple arterial dissections, physicians should carefully perform endovascular interventional procedures for patients with long-term RA.

Hemodynamic study about cortical hyperintensity belt sign after direct bypass surgery for moyamoya disease.

Transient neurological events (TNEs) are observed after direct bypass surgery in patients with moyamoya disease (MMD). Although a correlation between cortical hyperintensity belt signs (CHBs) and TNEs has been reported, the pathophysiology of CHBs is still unknown. The purpose of this study was to reveal the pathophysiology of CHBs by using dynamic susceptibility contrast-magnetic resonance imaging. Thirty patients with MMD were included in this study. We provided scores (0-2) for the existence of CHBs on postoperative FLAIR images. We placed the ROI for the presented area of CHBs in the images of cerebral blood flow, CBV, and MTT. We calculated the change of the hemodynamic parameters (increase ratio, IR) and analyzed the relationship between IRs, CHB scores, and TNEs. TNEs were observed in 15 cases (50%) and CHBs were detected in 28 cases (93%). TNEs showed significantly higher CHB scores than those without (p < 0.05). The group of CHB score 2 showed a significantly higher CBV IR than the group with of score 0 (p < 0.05). Patients with TNEs showed a significantly higher CBV IR than those without (p < 0.05). As for the cut-off level to predict an appearance of TNEs, the CBV IR was 1.36 by the Receiver Operating Characteristic analysis, and the sensitivity and specificity were 80% respectively. We hypothesize that the pathophysiology of the CHBs are vasogenic edemas because the postoperative CBV increase correlated with the CHBs.

Cortical Venous Reddening Predicts Remote Cerebral Infarction Post Superficial Temporal Artery-Middle Cerebral Artery Bypass in Atherosclerotic Occlusive Cerebrovascular Disease.

BACKGROUND: The superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis (STA-MCA bypass) currently is performed to prevent atherosclerotic occlusive cerebrovascular disease. However, the benefits of the bypass surgery remain controversial. To ensure consistent surgical benefits, understanding the mechanisms of perioperative cerebral infarction (CI) is required. Moreover, appropriate patient selection procedures must be determined to decrease the rate of perioperative stroke. We retrospectively investigated patients who underwent bypass surgery at our institution and determined that the patients who presented with cortical venous reddening after anastomosis during the surgery developed perioperative CI. METHODS: A total of 45 consecutive patients who underwent bypass surgery were retrospectively investigated. Twenty-five of the 45 patients underwent bypass for atherosclerotic occlusion or stenosis of the internal carotid artery or middle cerebral artery. Preoperative iodine-123-N-isopropyl-iodoamphetamine single-photon emission computed tomography was performed with and without acetazolamide administration. Change in color of the cortical veins was observed on recorded surgical videos, and its correlation with perioperative CI was investigated. RESULTS: We experienced 2 cases of perioperative extensive CI at a region remote from the site of anastomosis. In both cases, retrospective investigation of surgical videos demonstrated reddening of cortical veins soon after the anastomosis procedure. Of all 45 patients, postoperative CI and venous reddening were observed in only these 2 cases. CONCLUSIONS: We determined that patients presenting with cortical venous reddening after anastomosis developed perioperative CI. Cortical venous reddening may be an important predictor for the occurrence of CI after STA-MCA bypass surgery for patients with atherosclerotic occlusive cerebrovascular disease.

Internal carotid artery aneurysms diagnosed after stereotactic radiosurgery for a growth hormone-secreting pituitary adenoma: a case report and literature review.

Radiation therapy is associated with the subsequent development of cerebral aneurysms; however, stereotactic radiosurgery (SRS)-associated aneurysm cases have not been well documented, with only 18 cases reported to date. We present a case of intracranial aneurysms with the rupture occurring 20 years after SRS for a growth hormone-producing pituitary adenoma. This is the first report of aneurysms diagnosed following transsphenoidal surgery and SRS for pituitary adenoma. We believe that the aneurysm reported here is a consequence of the SRS treatment, and thus this may be a very rare long-term complication following radiation treatments.

Surgical Treatment of Spontaneous Internal Carotid Artery Dissection with Abducent Nerve Palsy: Case Report and Review of Literature.

BACKGROUND: Sixth-nerve palsy often develops as a result of trauma, neoplasm, or vascular disease affecting the pons. Less commonly, this palsy can be caused by pathology of the internal carotid artery in the cavernous sinus region. Here, we describe a rare case of spontaneous dissection of the internal carotid artery in the cavernous sinus accompanied by acute sixth nerve palsy that was successfully treated with surgery. CASE DESCRIPTION: An 18-year-old man presented suddenly and spontaneously with isolated abducent nerve palsy. His magnetic resonance angiography identified a dissection of the right internal carotid artery in the cavernous sinus. We successfully treated it with high-flow bypass and ligation of the internal carotid artery (ICA). CONCLUSIONS: Intracavernous ICA dissection is a possible cause of sixth nerve palsy. While most cases likely result from compromised arterial blood supply to the affected nerve, compression of the cranial nerves by the expanded artery can occur in some cases. Surgical treatment is a safe and effective option for relieving nerve compression after intracavernous ICA dissection.

Macrophage-Derived Angiopoietin-Like Protein 2 Exacerbates Brain Damage by Accelerating Acute Inflammation after Ischemia-Reperfusion.

Ischemic stroke is a leading cause of death and disability worldwide. Several reports suggest that acute inflammation after ischemia-reperfusion exacerbates brain damage; however, molecular mechanisms underlying this effect remain unclear. Here, we report that MAC-3-positive immune cells, including infiltrating bone marrow-derived macrophages and activated microglia, express abundant angiopoietin-like protein (ANGPTL) 2 in ischemic mouse brain in a transient middle cerebral artery occlusion (MCAO) model. Both neurological deficits and infarct volume decreased in transient MCAO model mice established in Angptl2 knockout (KO) relative to wild-type mice. Acute brain inflammation after ischemia-reperfusion, as estimated by expression levels of pro-inflammatory cytokines such as interleukin (IL)-1ß and tumor necrosis factor alpha (TNF)-α, was significantly suppressed in Angptl2 KO compared to control mice. Moreover, analysis employing bone marrow chimeric models using Angptl2 KO and wild-type mice revealed that infiltrated bone marrow-derived macrophages secreting ANGPTL2 significantly contribute to acute brain injury seen after ischemia-reperfusion. These studies demonstrate that infiltrating bone marrow-derived macrophages promote inflammation and injury in affected brain areas after ischemia-reperfusion, likely via ANGPTL2 secretion in the acute phase of ischemic stroke.

Prolonged Mean Transit Time Detected by Dynamic Susceptibility Contrast Magnetic Resonance Imaging Predicts Cerebrovascular Reserve Impairment in Patients with Moyamoya Disease.

BACKGROUND: Evaluating cerebrovascular reserve (CVR) is important for patients with moyamoya disease (MMD). 123I-iodoamphetamine single-photon emission CT (SPECT) with acetazolamide (ACZ) challenge is widely carried out, but using ACZ becomes problematic owing to its off-label use and its adverse effects. Here, we report the efficacy of dynamic susceptibility contrast MRI (DSC-MRI) for the evaluation of CVR in MMD patients. METHODS: All 33 MMD patients underwent both SPECT and DSC-MRI at an interval of <10 days from each other (mean age 38.3 years). The region of interest (ROI) was the anterior cerebral artery (ACA) territory, middle cerebral artery (MCA) territory, basal ganglia and cerebellum hemisphere for cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) images. The ratios of the ROIs to the ipsilateral cerebellum were calculated for each parameter and evaluated. The CVR was calculated using images acquired by SPECT before and after ACZ administration. The ratios of DSC-MRI parameters and CVR were compared and evaluated for each ROI. RESULTS: The MTT of the ACA and MCA territories significantly correlated with CVR (p < 0.0001). However, CBF and CBV had no correlation with CVR. The MTT ratio had a threshold of 1.966, with a sensitivity of 68.4% and a specificity of 91.5% for predicting decreased CVR (<10%). CONCLUSION: MTT had a negative correlation with CVR. DSC-MRI is easy, safe and useful for detecting decreased CVR and can be used as a standard examination in MMD patient's care.