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

Background and Purpose: Evaluation of cerebral blood flow (CBF) after carotid and cerebral revascularization is essential for early detection of hyperperfusion phenomenon. Single photon emission computed tomography (SPECT) is considered to be a standard modality for evaluation of CBF. It has, however, difficulty in real-time and repetitive evaluation. Recently, arterial spin labeling MRI (ASL-MRI) has evolved with advantages of its immediacy and repetitivity. The purpose of this study is to elucidate the usefulness of ASL-MRI for evaluation of CBF after carotid and cerebral revascularization. Methods: We screened the adult patients who underwent ASL-MRI and SPECT within 24 hours of interval after carotid endarterectomy (CEA), carotid stenting (CAS), or extracranial-intracranial bypass (EC-IC bypass). After excluding the cases of poor image quality, 63 cases (23 CEA, 22 CAS, 18 EC-IC bypass) were enrolled into the study. ASL-MRI (Siemens 3.0T Magnetom Prisma; 2D-PICORE, Voxel size 1.5x1.5x4mm, TR/TE/TI=4000/15.66/1800-2500) were obtained within 24 hours after surgery. SPECT were obtained using N-isopropyl-p-[123I]iodoamphetamine with autoradiography technique. If abnormal CBF increase (≧20%) were detected, patients were treated with anti-hypertensive therapy, and underwent repeated ASL-MRI and SPECT for therapeutic evaluation. Results: Abnormal CBF increase were observed in 6 cases (2 CEA, 2 CAS, and 2 EC-IC bypass) in SPECT, and 4 (2 CEA, 2 EC-IC bypass) in ASL-MRI. In CEA, 2 cases of CBF increase detected in SPECT were also detected in ASL-MRI. In CAS, ASL-MRI did not visualize CBF increase as clearly as in SPECT. In EC-IC bypass, 2 cases of CBF increase detected in SPECT were also detected in ASL-MRI. The patient with increased CBF after revascularization surgery were treated with anti-hypertensive drugs and remained asymptomatic. Conclusion: ASL-MRI was useful for evaluation and early detection of abnormal CBF in CEA and EC-IC bypass, although not in CAS. Decay of radiofrequency pulse due to metallic material is supposed to be the reason. In cases of CEA and EC-IC bypass, ASL-MRI is expected to be an alternative to SPECT with its advantage of immediacy and repetitivity.

Background and Purpose: Small vessel infarction after cranial irradiation is rare manifestation, whereas large vessel disease is well-known as a late complication. The purpose of this study is to investigate the clinical features of the small vessel infarction associated with the previous cranial irradiation. Patients and Methods: This is a retrospective chart review study of the patients presenting with small vessel infarction after cranial irradiation, retrieved from the single center database between 1998 and 2015. We reviewed the clinical characteristics, types and doses of irradiation, interval between first irradiation and first stroke, radiographic findings of the infarctions, and clinical courses. Results: Thirteen cases were identified, 12 men, 54 +/- 14 years of age at stroke onset. Underlying diseases for irradiation were 8 primary brain tumor, 4 metastatic brain tumor, 1 Leukemia, and 1 histologically undetermined brain tumor. Irradiation methods were 9 whole brain irradiation, 2 intensity modulated radiation therapy, and 2 local irradiation. Mean dose of irradiation was 51 +/- 10 Gy. Infarcted lesions were 8 corona radiata, 5 posterior limb of internal capsule, 1 thalamus. Mean time from first irradiation to first stroke was 14 +/- 14 years. Median NIHSS score at onset was 4 (min-max: 1-11), and median modified Rankin Scale at discharge was 3 (min-max: 1-4). One case had recurrence of infarction in the different territory of perforating artery, and one case had exacerbation due to infarction growth. Conclusions: Vasculopathy after irradiation also occurs in perforating arteries as well as in large vessels. Irradiation induced small vessel vasculopathy should be recognized as an important cause of stroke among brain tumor survivor.

It is now accepted that carotid artery stenosis should be treated as a part of systemic atherothrombosis. However, little is known about the association in atherosclerosis between the carotid and coronary arteries. We retrospectively investigated the association between carotid plaque vulnerability diagnosed on carotid magnetic resonance imaging (MRI) and coexisting coronary artery stenosis in patients scheduled for carotid endarterectomy (CEA) or carotid artery stenting (CAS). Eighty-nine consecutive cases that underwent carotid reconstruction for carotid artery stenosis at Kyoto University Hospital between 2010 and 2015 were enrolled in this study. Ten cases that received neither coronary angiography (CAG) nor coronary computed tomography angiography (CCTA) as preoperative examinations, 6 cases with restenosis after CEA or CAS, and 2 cases that did not undergo carotid MRI were excluded. We evaluated relative overall signal intensity (roSI) of the carotid plaque on T1-weighted imaging and coronary artery stenosis detected on CAG or CCTA in the remaining 71 cases. Carotid plaques with roSI >1.5 were defined as MRI-detected vulnerable plaques. Thirty-one cases had a history of previous coronary intervention (stenting or bypass surgery), of which 26 (84%) showed carotid vulnerable plaques. In the cases with no history of coronary intervention, coronary artery stenosis was newly detected in 21 cases, and was not demonstrated in the other 19 cases. Fifteen of the 21 cases with coronary artery stenosis (71%) also showed carotid vulnerable plaques. On the other hand, only 4 of the 19 cases without coronary artery stenosis (21%) had carotid vulnerable plaques, representing a significant difference (P Among the cases with no history of coronary intervention, prevalence of coronary artery stenosis in cases with carotid vulnerable plaques was 79%, significantly higher than that in cases without carotid vulnerable plaques (29%). In conclusion, this study demonstrated that patients with carotid vulnerable plaques are more likely to have advanced coronary artery stenosis. Plaque characterization by carotid MRI is useful not only for treatment of carotid artery stenosis, but also for predicting coronary artery stenosis.

[Background and Purpose] Neuro-interventional radiology (NIVR) is increasingly recognized as an essential option for acute stroke treatment. However, the access to NIVR physician or NIVR-capable hospital is still limited. Patient transfer system between primary stroke centers (PSCs) and comprehensive stroke centers has a problem about deterioration during transfer, insufficient information transmission, small area coverage, and loss of time. We organized a mobile NIVR team consisting of 6-7 board certified NIVR physicians, and concluded a NIVR alliance program with affiliating PSCs. The team performed procedures at the local sites on request of PSCs. [Methods] Between 2008 and 2012, we concluded a NIVR alliance program with 7 affiliated PSCs. The team dispatched NIVR physicians to the PSCs immediately after receiving "rescue call." Clinical information including medical images was updated in real-time and interactive manner during travel. [Results] We received 23 calls and reacted to all cases. We treated 8 cases of acute ischemic stroke (6 mechanical thrombectomy, 3 carotid stenting, 5 for non-responder to intravenous rt-PA), and 15 for subarachnoid hemorrhage (14 aneurysm embolization, one parent artery occlusion). The mean travel distance was 39.0 km (min - max: 6.3 - 90.3). For acute ischemic stroke, the mean "door-to-puncture time" was 154 minutes (min - max: 130 - 168). For subarachnoid hemorrhage, procedure was performed on the onset or the next day. All the procedure were successfully performed and no deterioration related to procedure were observed. [Conclusions] The new application of NIVR delivery system can safely enable to avoid deterioration during transfer, cover larger area without delay, and enlarge the opportunity to access NIVR therapy for acute stroke patients.