Search

Background and Purpose— Only a small percentage of stroke patients are treated with thrombolytic therapy. We sought to determine whether vessel occlusion in mild strokes represented a new target population for interventional therapy. Methods— We imaged 106 acute stroke patients with MRI. Patients were identified with evidence of middle cerebral artery (MCA) occlusion and mild or no stroke signs (National Institutes of Health Stroke Scale [NIHSS] ≤3). They were compared with patients with signs of stroke, NIHSS >3, and MCA occlusion. Results— We identified 5 patients with absent flow on MRA in the MCA and mild or no stroke signs (NIHSS ≤3). All 5 were functionally independent at 3 months. Conclusions— Caution should be exercised in considering thrombolytic therapy in these patients. Quantification of perfusion imaging is required to identify “at risk” mild stroke populations.

Background and Purpose— There is ongoing controversy about the impact of hemorrhagic transformation after thrombolysis on long-term functional outcome. We sought to study the relation between the type of hemorrhagic transformation on CT scans and functional outcome. Methods— Data were obtained from the Canadian Alteplase for Stroke Effectiveness Study. This study was established as a registry to prospectively collect data for acute stroke patients receiving intravenous alteplase within 3 hours from stroke onset between February 1999 and June 2001. Follow-up was completed at 90 days, and good functional outcome was defined as a modified Rankin Scale score of 0 or 1. Copies of head CT scans obtained at 24 to 48 hours after starting treatment were read in consensus by a central reading panel consisting of 1 neuroradiologist and 1 stroke neurologist. According to European Cooperative Acute Stroke Study criteria, hemorrhagic transformation was classified as none, hemorrhagic infarction (HI-1 and HI-2), or parenchymal hematoma (PH-1 and PH-2). We compared outcome across groups and performed a multivariable analysis including previously determined important predictors of good outcome in acute ischemic stroke. Results— From 1135 patients enrolled at 60 centers across Canada, 954 follow-up CT scans were assessable. We observed some hemorrhagic transformation in 259 of 954 (27.1%) patients (110 HI-1, 57 HI-2, 48 PH-1, and 44 PH-2). Proportions of patients with good outcome were 41% with no hemorrhagic transformation, 30% with HI-1, 17% with HI-2, 15% with PH-1, and 7% with PH-2 ( P 2 test). After adjustment for age, baseline serum glucose, baseline Alberta Stroke Program Early CT score, and baseline National Institutes of Health Stroke Scale score, HI-1 was not a predictor of outcome. However, HI-2 (odds ratio=0.38, 95% CI=0.17 to 0.83), PH-1 (odds ratio=0.32, 95% CI=0.12 to 0.80), and PH-2 (odds ratio=0.14, 95% CI=0.04 to 0.48) were all negative predictors of outcome. Conclusions— The likelihood of a poor outcome after thrombolysis was proportional to the extent of hemorrhage on CT scans. HI grades of hemorrhagic transformation may not be benign.

The authors measured the association of early ischemic change on CT scan, measured using the Alberta Stroke Programme Early CT score (ASPECTS), and functional outcome in 825 patients with anterior circulation stroke treated with IV thrombolysis within 3 hours of onset. ASPECTS predicted outcome in a graded fashion (linearly for ASPECTS 6 through 10; pattern ill-defined for ASPECTS 0 through 5) but discriminated individual outcomes weakly. Except perhaps when early ischemic change is extensive, clinicians should not estimate prognosis using ASPECTS alone.

Background and Purpose— The Alberta Stroke Program Early CT Score (ASPECTS) is a grading system to assess ischemic changes on CT in acute ischemic stroke. CT angiography–source images (CTA-SI) predict final infarct volume. We examined whether the final infarct ASPECTS and clinical outcome were more related to acute CTA-SI ASPECTS than to the acute noncontrast CT (NCCT) ASPECTS. Methods— ASPECTS was assigned by 2 raters on the acute NCCT, CTA-SI, and follow-up imaging. The mean baseline ASPECTS of acute NCCT and CTA-SI was compared with the follow-up ASPECTS. Rate ratios (RRs) were used to quantify the relationship between the dichotomized baseline ASPECTS (categorized as 0 to 7 versus 8 to 10) and favorable patient outcome. Results— Thirty-nine patients were recruited. Proximal occlusion (internal carotid artery or middle cerebral artery) was seen in 62%, M2 occlusion in 18%, and no occlusion was seen in 20% of patients. The median time between symptom onset and imaging was 1.9 (1.2 to 2.5) hours. There was a significantly larger difference of 1.4 between the mean baseline NCCT and CTA-SI ASPECTS in patients who had more ischemic changes (follow-up ASPECTS=0 to 3) than a difference of 0.6 in patients who had near-to-normal CT scans (follow-up ASPECTS=8 to 10). The rate of favorable outcome for acute NCCT ASPECTS of 8 to 10 was 51.8% versus 25.0% for 0 to 7 (RR, 2.1, 95% CI: 0.7 to 5.9, P =0.12). For acute CTA-SI ASPECTS of 8 to 10, the rate of favorable outcome was 58.8% versus 31.8% for 0 to 7 (RR, 1.8, 95% CI: 0.9 to 3.8, P =0.09). Conclusions— CTA-SI ASPECTS provides added information in the prediction of final infarct size.

OBJECTIVES: In this study we define the probability of vascular abnormality in the middle cerebral artery (MCA) territory according to the extent of ischaemic change seen using computed tomography (CT). We assessed the sensitivity and specificity of the hyperdense middle cerebral artery (HMCA) and the "dot" sign using magnetic resonance angiography (MRA). METHODS: Patients presenting with ischaemic stroke had a CT scan (

To the Editor: We read with interest the article by Mak et al1 in which baseline CT scans of stroke patients were compared using ASPECTS2 and the >⅓ middle cerebral artery (MCA) territory rule.3 The group found only a moderate interobserver agreement with ASPECTS. However, only a brief, 30-minute training session was performed, and therefore it is not surprising that reliability was only moderate. No details are given as to how the ASPECTS score was generated. Were all slices or just one slice evaluated at both the basal ganglia and supraganglionic levels? We acknowledge that more detailed methodology has now been published,4 which should improve reliability at less-experienced centers. Intriguingly, we note that Mak et al duplicated our observations by detecting more early changes when using ASPECTS. This is perhaps one of the biggest advantages of ASPECTS. By its nature it forces a rater to look at every part of the MCA …

To the Editor: In their abstract, Schramm et al, describe lesions seen on CT angiography source images (CTA-SI) as “demarcation of irreversible infarct.”1 We believe this description is inaccurate and have several comments regarding the utility and future study of CTA-SI. First, CTA-SI gives direct information about flow of contrast into the tissues and not about the viability of tissue. The inference that hypointense tissue is “irreversible infarct” may be time dependent. Irreversible damage may have occurred in most cases with clear hypointensity on CTA-SI at late time points after stroke onset, but this may not necessarily be true in the very early phase of infarct evolution. In Table 1, the authors report six cases in which the size of the area of CTA-SI hypointensity is bigger than the abnormal area of hyperintensity seen on the MR diffusion weighted image which was obtained following the CT. It has yet to be proven that volumes delineated on CTA-SI imply irreversibly damaged tissue in all cases and the relationship with time from stroke onset has not been clarified. Second, in the displayed examples, …

The treatment of intraluminal thrombus at the common carotid bifurcation in patients with an ischemic cerebral event is controversial. Some favour anticoagulation whilst others suggest emergency carotid endarterectomy. A personal series of seven cases is presented. Five patients continued having ischemic events whilst on anticoagulants. Six faired excellently following emergency endarterectomy with no postoperative ischemic events and were well at between 3 and 6 months postoperatively. The operation for one patient was planned for 24 h following the angiogram, but unfortunately she suffered a severe stroke at 18 h whilst on heparin.