Calcification and endothelialization of thrombi in acute stroke.

We report chronic histopathological features in thrombi mechanically retrieved from five acute ischemic stroke patients with a median age of 68 years and a median pretreatment National Institutes of Health Stroke Scale score of 13. Early endothelialization occurred over and within the thrombus, and calcifications were seen, in addition to the usual acute laminar fibrin, intervening red blood cells, and neutrophils. The effectiveness of tissue plasminogen activator in clot dissolution might be affected by these features, if extensive. Thrombus composition could critically determine the success of chemical thrombolysis. Our results should stimulate the development of imaging modalities to determine thrombus composition.

Communicating hydrocephalus after endovascular coiling of unruptured aneurysms: report of 2 cases.

To the authors' knowledge, only 1 case of communicating hydrocephalus after endovascular coiling of unruptured brain aneurysms has been reported previously. Here, they report on 2 such cases of delayed communicating hydrocephalus after treatment with hydrogel-coated coils and offer the first histopathological evidence of foreign material, presumably related to the coils, as the cause of hydrocephalus.

Intra- and inter-rater reliability of the anterior atlantodental interval measurement from conventional lateral view flexion/extension radiographs.

An investigation of intra- and inter-rater reliability anterior atlantodental interval (AADI) measurements was conducted using flexion/extension plain radiographs. Flexion and extension lateral radiographs of individuals investigated for atlantoaxial instability were measured for AADI on three occasions. Intra-rater intraclass correlation coefficients (ICC) were calculated for both flexion (0.99) and extension (0.96). Inter-rater ICCs were 0.93 and 0.84 for flexion and extension, respectively. The AADI measurement proved to be reproducible with a minimal standard of error, between and within raters.

Interobserver variation of ASPECTS in real time.

BACKGROUND: The Alberta Stroke Program Early CT Score (ASPECTS) has been used to quantify early ischemic changes on computed tomography (CT) brain scans of acute stroke patients. We sought to assess the reliability of the score when performed in real time as compared with an expert rating performed at a later time point. METHODS: Two hundred fourteen patients presenting with acute ischemic stroke or transient ischemic attack were prospectively recruited if they had a brain CT scan performed within 12 hours of symptom onset. Each scan was read for ASPECTS prospectively by the treating physician and later by 1 expert reader. A weighted kappa statistic was used to determine the interobserver agreement. RESULTS: The median baseline National Institutes of Health Stroke Scale score was 5 (range: 0 to 32) and the median time to CT scan was 152 minutes (range: 22 to 769). The interobserver agreement between ASPECTS performed in real time and expert ASPECTS was substantial (kappa(w)=0.69). The mean difference between real-time ASPECTS and expert ASPECTS was 0 (SD: 1.1). CONCLUSIONS: ASPECTS is a reliable clinical scale for rating early ischemic changes on CT when performed in real time.

Hyperperfusion syndrome: toward a stricter definition.

OBJECTIVE: Hyperperfusion syndrome is a rare and potentially devastating complication of carotid endarterectomy or carotid artery angioplasty and stenting. With the advent of new imaging techniques, we reviewed our experience with this phenomenon. METHODS: This report is a retrospective review of 129 consecutive cases of carotid endarterectomy performed between June 1, 2000, and May 31, 2002, and 44 consecutive cases of carotid artery angioplasty and stenting performed between January 1, 1997, and May 31, 2002. We specifically searched for examples of patients who developed postprocedural nonthrombotic neurological deficits that typified the hyperperfusion syndrome. RESULTS: Seven cases of hyperperfusion syndrome occurred, four after endarterectomy (3.1% of carotid endarterectomy cases) and three after stenting (6.8% of stenting cases). The cases of hyperperfusion were classified as presenting with 1). acute focal edema (two cases with stroke-like presentation, attributable to edema immediately after revascularization), 2). acute hemorrhage (two cases of intracerebral hemorrhage immediately after stenting and one case immediately after endarterectomy), or 3). delayed classic presentation (two cases with seizures, focal motor weakness, and/or late intracerebral hemorrhage at least 24 hours after endarterectomy). CONCLUSION: Hyperperfusion syndrome may be more common and more variable in clinical presentation than previously appreciated.

Intracranial thrombus extent predicts clinical outcome, final infarct size and hemorrhagic transformation in ischemic stroke: the clot burden score.

BACKGROUND: In ischemic stroke, functional outcomes vary depending on site of intracranial occlusion. We tested the prognostic value of a semiquantitative computed tomography angiography-based clot burden score. METHODS: Clot burden score allots major anterior circulation arteries 10 points for presence of contrast opacification on computed tomography angiography. Two points each are subtracted for thrombus preventing contrast opacification in the proximal M1, distal M1 or supraclinoid internal carotid artery and one point each for M2 branches, A1 and infraclinoid internal carotid artery. We retrospectively studied patients with disabling neurological deficits (National Institute of Health Stroke Scale score >or=5) and computed tomography angiography within 24-hours from symptom onset. We analyzed percentages independent functional outcome (modified Rankin Scale score

MRI of ischemic stroke in canines: applications for monitoring intraarterial thrombolysis.

PURPOSE: To describe a canine embolic stroke model that is appropriate for endovascular procedure evaluations and develop local cerebral blood flow (CBF) maps to monitor the progression of stroke and thrombolysis. In the future, MR may displace X-ray imaging in some endovascular procedures, such as intraarterial (IA) thrombolysis for stroke therapy, due to increased monitoring capabilities. For MR to attain its full potential in endovascular therapy, the development of appropriate disease models and monitoring techniques is essential. MATERIALS AND METHODS: The canine stroke model uses an injection of autologous clot to produce ischemic and infarcted tissue and produces a range of stroke severities within the anterior cerebral circulation. Local CBF maps were formed by using the catheter that would be in place to deliver the thrombolytic agent for treatment to deliver the gadolinium-based contrast agent for perfusion imaging. RESULTS: After the injection of clot, changes on imaging were consistent with the progression of ischemic stroke. Local CBF maps showed perfusion changes with stroke progression and treatment. CONCLUSION: We successfully demonstrate the progression of ischemic stroke in the canine to mimic the progression of human stroke. CBF maps to show local perfusion characteristics show great potential in the evaluation of stroke therapy.