This work is licensed under Creative Commons Attribution 4.0 License ANN.MS.ID.000599.

IntroductionMinimising delay in thrombolysis is a key outcome in acute stroke care.MethodsA 3 year retrospective cohort analysis of all acute stroke admissions in Wollongong Hospital, a major regional referral centre in New South Wales, was completed to determine the causes of in-hospital delays for thrombolysis. Data collected included age, baseline National Institute of Health Stroke Scale (NIHSS) score, onset time, arrival time, CT imaging & reporting time and outcomes of the event.ResultsFrom 656 admissions, 70 cases of thrombolysis were recorded 56 cases of endovascular thrombectomy. The mean time from onset to arrival was 85 minutes, from arrival to CT was 31 minutes and from door to needle time (DNT) was 108 minutes. Multiple regression analysis revealed a an inverse linear association between onset to arrival time and DNT. Age, stroke severity and gender were not shown to impact treatment times. The results showed that there was a paradoxical association between arrival time and DNT. The cause for this was not clearly identified but similar to previous studies is likely to be contributed by a lack of urgency when initiating management.1 2ConclusionFor every 30-minute delay in hospital arrival, there was a 13- minute reduction in DNT. In light of this, education trials to promote ‘time equals brain’ understanding amongst stroke first responders is being implemented to aim to reduce DNT to less than 80 minutes. The results of this are anticipated to be available in mid 2019.ReferencesAlbers GW, Bates VE, Clark WM. Intravenous tissue-type plasminogen activator for treatment of acute stroke: The Standard Treatment with Alteplase to Reverse Stroke (STARS) Study. Journal of the American Medical Association 2000; 283:1145–1150.Romano JG, Muller N, Merino JG, Forteza AM, Koch S, Rabinstein AA. In-hospital delays to stroke thrombolysis: paradoxical effct of early arrival. Neurological Research 2007;29:664–666.

parallel to each other in the central arm of an 'H'. This study aimed to determine the population variance in chiasmal shape. Methods 68 MRI scans of healthy individuals without visual abnormality were randomly selected. A 2D image was created and images were analysed using AutoCAD software to determine the offset between lines drawn down the centres of the optic nerves and contralateral optic tracts. A positive offset would suggest an 'H' shape while an 'X'-shaped chiasm would have a offset of 0. Results The mean width of the chiasm was 12.0 mm, and the mean offset was 4.7 mm generating a mean offset:width ratio of 0.38. No chiasm had an offset of zero. Fibre crossings occurred approximately 2.35 mm lateral to the midline, and nasal (crossing) fibres travelled an average of 4.7 mm in the mediolateral plane before entering the contralateral optic tract. Conclusions The human optic chiasm is H-shaped, not Xshaped. This information will inform future models of chiasmal compression.