The overall study population
is a prospective cohort of consecutive TCD examinations in acute anterior circulation ischemic stroke patients presenting within 6 h of symptom onset. The cohort was collected between June 2007 and January 2010. Eligibility criteria were presence of a demonstrated occlusion of either Selleck PLX4032 MCA or ICA on baseline acute CTA in a patient undergoing assessment for potential suitability for intravenous thrombolytic therapy. A subgroup of patients with MCA occlusion and baseline TIBI grades ≤3 treated with intravenous thrombolysis was used to study recanalization features and MES characteristics. Patients were excluded if a pre-morbid Rankin score (mRS) was greater than 3 or serious co-morbid illness limited the patient’s life expectancy, if posterior circulation stroke was suspected, of temporal acoustic windows were inadequate, if unilateral ACA hypoplasia or aplasia was evident on CTA (dominant ACA at least twice the Akt inhibition size of the contralateral
ACA  and ). Stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS). Patient outcome was determined using the NIHSS at 24 h from stroke onset modified Rankin scale at 90 days blind to imaging data. The study was approved by the institutional ethics committee and individual patient consent was obtained. TCD ultrasound was performed using a digital power-motion Doppler unit (PMD 100, Spencer Technologies) with 2-MHz pulsed wave diagnostic transducers. The initial TCD examination was performed immediately prior to commencement of intravenous t-PA, or immediately following CT scanning in the case of those not eligible for thrombolysis. The insonation protocol was as follows: initially the non-affected MCA was insonated from a depth of 60–45 mm as a unidirectional signal towards the probe. This included M1 and M2 segments to determine the depths and velocity ranges and continued to bifurcation, terminal ICA (TICA), ACA and PCA. The proximal ACA waveform was determined from a depth of 60–70 mm as a unidirectional signal away from the probe.
Next, the affected MCA waveform was determined and then the bifurcation, TICA, ACA and PCA. Flow measurements for ACA FD were taken at ACA A1 segment mafosfamide (depth 60–70 mm) as a flow away from the probe. The ophthalmic arteries (depths: 40–50 mm) and ICA siphons (55–65 mm) were then checked for flow direction and pulsatility through the transorbital windows bilaterally . Peak systolic, diastolic and mean flow velocities and pulsatility indices were measured off-line. FD was considered present when the ipsilateral ACA mean blood flow velocity was at least 30% greater than that of the contralateral ACA  and . All TCD studies and measurements were attended by an experienced sonographer (DQ) who remained blind to CT and MR imaging data. Baseline measurements and vessel segment insonation were checked where appropriate by another experienced sonographer (CRL).