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Disappearance of the hyperdense middle cerebral artery sign (HMCAS) following intravenous thrombolysis for ischaemic stroke is associated with improved outcome. Debate exists over which radiological thrombus characteristics can predict disappearance of the HMCAS after thrombolysis such as vessel attenuation or extent of thrombus length.Methods Ischaemic stroke patients treated with intravenous thrombolysis from our hospital were entered into a European registry. Patient demographics, stroke severity pre- and 24 hours post-thrombolysis were recorded. Patients with HMCAS were identified from the registry using records from 2010–2013. Images from the pre and post-thrombolysis computed tomography scan were measured. Thrombus characteristics (length and attenuation), extent of ischaemic change and clinical outcome (stroke severity and 3 month survival) were compared between patients with and without HMCAS disappearance. Logistic regression analysis was performed to identify predictors of HMCAS disappearance.Results HMCAS was present in 88/315 (28%) of thrombolysed ischaemic stroke patients. 36/88 (41%) of patients had thrombus disappearance 24 hours after thrombolysis. HMCAS disappearance was associated with reduced stroke severity, less radiological ischaemic change, and higher 3 month survival (87% vs 56%). Median thrombus length was shorter in the HMCAS disappearance group (11 vs 17 mm, p = 0.0004), but no significant difference in vessel attenuation was observed (48 vs 51 Hounsfield Units, p = 0.25). HMCAS disappearance occurred in 73% of cases where HMCAS length was < 10 mm, 38% when length was 10–20 mm, and 21% if > 20 mm. Thrombus length was the only independent predictor of HMCAS disappearance (odds ratio 0.90 per mm; 95% CI 0.84-0.96, p = 0.01).Conclusion Disappearance of HMCAS is associated with better clinical and radiological outcomes. A shorter thrombus is more likely to disappear post-thrombolysis. The data highlight the limitation of intravenous thrombolysis in patients with longer hyperattenuated vessels, and the potential role for clot retrieval in such patients.

Intravenous thrombolysis increases disability-free survival after acute ischaemic stroke in a time-dependent fashion. We aimed to determine whether pre-hospital notification, introduction of a CT scanner near to assessment site and introduction of out-of-hours thrombolysis services affect thrombolysis timing.Methods Timings related to thrombolysis were collected between May 2012 and June 2014 at a single hospital site; these included time to stroke physician assessment, time to cranial CT imaging and door to needle time. All thrombolysed ischaemic stroke patients admitted via the emergency department were included. Ambulance services were asked to pre-notify the emergency department of any suspected stroke patient during this period.Results We studied 182 patients (48% female; mean age 74 years; 59% pre-notified). Pre-hospital notification was associated with a significantly higher rate of CT scanning within 25 minutes (60% vs 24%, odds ratio [OR] 4.7, 95% confidence interval [CI] 2.4–9.0; p<0.001), earlier stroke physician assessment (median 6 vs 32 minutes; p<0.001) and receiving thrombolysis within 60 minutes (89% vs 49%, OR 8.0, 95% CI 3.8–16.9; p<0.001). Being treated outside normal working hours did not alter thrombolysis timing. Logistic regression identified the introduction of a near-site CT scanner (OR 4.6 [95% CI 1.7–12.5]) and pre-hospital notification (OR 4.7, [95% CI 2.3–9.6]) as independent predictors of door to CT time =25 minutes, and pre-hospital notification (OR 11.6, [95% CI 4.9-30.3]) and stroke severity (OR 1.15 per point of NIHSS scale, [95% CI 1.08-1.23]) as predictors of door to thrombolysis time =60 minutes. The most common perceived timing delays were radiology-related (33%), the need to acutely lower blood pressure (15%) and obtaining consent (12%).Conclusion Pre-hospital notification is associated with earlier stroke physician review, CT imaging and delivery of thrombolysis. Referral to an out of hours thrombolysis service was not associated with additional delay.

The ultrasonic absorption of sickle cells was compared with the morphological changes in these cells are produced by varying oxygen tensions and pH. A decrease in oxygen tension caused increased sickling and an increase in the ultrasonic absorption of the blood. An increase in pH reduced the ultrasonic absorption and decreased sickling. These findings indicate that ultrasonic absorption can detect changes in the aggregation state of sickle cell hemoglobin in situ within the red cell and that the method may be used to monitor the degree of sickling under various environmental conditions.

The ultrasonic absorption of sickle cells was compared with the morphological changes in these cells as produced by varying oxygen tensions and pH. A decrease in oxygen tension caused increased sickling and an increase in the ultrasonic absorption of the blood. An increase in pH reduced the ultrasonic absorption and decreased sickling. These findings indicate that ultrasonic absorption can detect changes in the aggregation state of sickle cell hemoglobin in situ within the red cell and that the method may be used to monitor the degree of sickling under various environmental conditions.

This report is of an atypical case of neuralgic amyotrophy with a Horner's syndrome, bilateral brachial plexus, lumbar plexus and phrenic nerve involvement. The diagnosis is confirmed based on a classical history and examination findings with typical neurophysiological investigations for this condition. This report also highlights the novel use of positional magnetic resonance imaging to investigate patients with respiratory muscle weakness. This case report expands the recognised clinical features of neuralgic amyotrophy and the literature concerning atypical features of this condition is reviewed.