Optimal CT perfusion thresholds for core and penumbra in acute posterior circulation infarction.

Background: At least 20% of strokes involve the posterior circulation (PC). Compared to the anterior circulation, posterior circulation infarction (POCI) are frequently misdiagnosed. CT perfusion (CTP) has advanced stroke care by improving diagnostic accuracy and expanding eligibility for acute therapies. Clinical decisions are predicated upon precise estimates of the ischaemic penumbra and infarct core. Current thresholds for defining core and penumbra are based upon studies of anterior circulation stroke. We aimed to define the optimal CTP thresholds for core and penumbra in POCI. Methods: Data were analyzed from 331-patients diagnosed with acute POCI enrolled in the International-stroke-perfusion-registry (INSPIRE). Thirty-nine patients with baseline multimodal-CT with occlusion of a large PC-artery and follow up diffusion weighted MRI at 24-48 h were included. Patients were divided into two-groups based on artery-recanalization on follow-up imaging. Patients with no or complete recanalisation were used for penumbral and infarct-core analysis, respectively. A Receiver operating curve (ROC) analysis was used for voxel-based analysis. Optimality was defined as the CTP parameter and threshold which maximized the area-under-the-curve. Linear regression was used for volume based analysis determining the CTP threshold which resulted in the smallest mean volume difference between the acute perfusion lesion and follow up MRI. Subanalysis of PC-regions was performed. Results: Mean transit time (MTT) and delay time (DT) were the best CTP parameters to characterize ischaemic penumbra (AUC = 0.73). Optimal thresholds for penumbra were a DT >1 s and MTT>145%. Delay time (DT) best estimated the infarct core (AUC = 0.74). The optimal core threshold was a DT >1.5 s. The voxel-based analyses indicated CTP was most accurate in the calcarine (Penumbra-AUC = 0.75, Core-AUC = 0.79) and cerebellar regions (Penumbra-AUC = 0.65, Core-AUC = 0.79). For the volume-based analyses, MTT >160% demonstrated best correlation and smallest mean-volume difference between the penumbral estimate and follow-up MRI (R 2 = 0.71). MTT >170% resulted in the smallest mean-volume difference between the core estimate and follow-up MRI, but with poor correlation (R 2 = 0.11). Conclusion: CTP has promising diagnostic utility in POCI. Accuracy of CTP varies by brain region. Optimal thresholds to define penumbra were DT >1 s and MTT >145%. The optimal threshold for core was a DT >1.5 s. However, CTP core volume estimates should be interpreted with caution.

Cerebrovascular Disease Profiles of Culturally and Linguistically Diverse Communities in South Western Sydney and New South Wales.

INTRODUCTION: Culturally and linguistically diverse (CALD) communities are growing globally. Understanding patterns of cerebrovascular disease in CALD communities may improve health outcomes through culturally specific interventions. We compared rates of transient ischaemic attack (TIA)/stroke (ischaemic stroke, intracerebral haemorrhage) and stroke risk factor prevalence in overseas and Australian-born people in South Western Sydney (SWS) and New South Wales (NSW). METHODS: This was a 10-year retrospective analysis (2011-2020) of SWS and NSW age-standardized rates per 100,000 person-years of TIA/stroke. Data were extracted from Health Information Exchange and Secure Analytics for Population Health Research and Intelligence systems. Rates of hypertension, type 2 diabetes mellitus (T2DM), atrial fibrillation (AF), smoking, and obesity were also calculated. RESULTS: The SWS and NSW age-standardized rate of TIA/stroke for people born in Australia was 100 per 100,000 person-years (100/100,000/year). In SWS, 56.6% of people were overseas-born compared to 29.8% for NSW. The age-standardized rate of TIA/stroke for Polynesian-born people was more than double that of Australian-born people (p < 0.001). Hypertension (33 [SWS] vs. 27/100,000/year [NSW]) and T2DM (36 [SWS] vs. 26/100,000/year [NSW]) were the most common risk factors with rates >50/100,000/year (hypertension) and >80/100,000/year (T2DM) for people born in Polynesia, Melanesia, and Central America. Rates of T2DM, AF, and obesity for Polynesian-born people were over threefold greater than people born in Australia. DISCUSSION/CONCLUSION: Greater rates of TIA/stroke were observed in specific CALD communities, with increased rates of cerebrovascular risk factors. Culturally specific, targeted interventions may bridge health inequalities in cerebrovascular disease.

Impact of interhospital transfer on patients undergoing endovascular thrombectomy for acute ischaemic stroke in an Australian setting.

OBJECTIVE: To assess the impact of interhospital transfer on the interplay between functional outcome, mortality, reperfusion rates and workflow time metrics in patients undergoing endovascular thrombectomy (EVT) for acute ischaemic stroke due to large vessel occlusion (LVO) in the anterior cerebral circulation. DESIGN SETTING AND PARTICIPANTS: This is an analysis of a prospective database of consecutive patients undergoing EVT for LVO presenting between January 2017 and December 2018 at a single Australian comprehensive stroke centre (CSC). Patients presented directly or were transferred to the CSC from 21 sites across New South Wales and the Australian Capital Territory. MAIN OUTCOME MEASURES: The main outcome measures were rate of good 90-day functional outcome (modified Rankin Scale 0-2), successful reperfusion (Thrombolysis in Cerebral Infarction scale grade 2b or 3), symptomatic intracerebral haemorrhage (sICH) and 90-day mortality. Key workflow time metric milestones were examined. RESULTS: 154 of 213 (72%) patients were interhospital transfers. There was no significant difference in baseline characteristics including age, National Institutes of Health Stroke Scale score, intravenous thrombolysis administration or procedure time between transferred and direct presenters (all p>0.05). Transferred patients had worse 90-day functional outcome (39.6% vs 61.0%, OR 0.42, 95% CI 0.23 to 0.78), higher mortality (25.3% vs 6.8%, OR 4.66, CI 1.59 to 13.70) and longer stroke onset to treatment (groin puncture) time (298 min vs 205 min, p<0.01). Successful reperfusion rates and sICH were similar between the cohorts (96.8% vs 98.3%, and 7.8% vs 3.4%). CONCLUSION: Interhospital transfer is associated with longer stroke onset to treatment, worse 90-day functional outcome and higher mortality compared with patients presenting directly to the CSC.

Cerebral venous thrombosis as a complication of intracranial hypotension after lumbar puncture.

BACKGROUND: Optic neuritis is recognised by the international classification of headache disorders as a painful cranial nerve lesion. A lumbar puncture may be performed in the investigation of optic neuritis. Postdural puncture headache (PDPH) due to intracranial hypotension is a frequent complication of this procedure. In contrast, cerebral venous thrombosis (CVT) is a rare but potentially fatal complication of dural puncture. A few studies have identified an association between iron deficiency anaemia and venous thrombosis. There are no reports linking CVT with lumbar puncture and iron deficiency anaemia. METHODS AND RESULTS: We present a 32-year-old woman with optic neuritis and iron deficiency anaemia complicated by a PDPH and CVT. CONCLUSION: CVT should be considered in a patient with persistent headache, recent lumbar puncture and iron deficiency anaemia. Early recognition and treatment of this condition are vital to avoiding mortality and morbidity.