Link to journal online
Toth, Gabor ; Albers, Gregory W.
Use of MRI to Estimate the Therapeutic Window in Acute Stroke: Is Perfusion-Weighted Imaging/Diffusion-Weighted Imaging Mismatch an EPITHET for Salvageable Ischemic Brain Tissue?
Source
Stroke. 40(1):333-335, January 2009.
Cai, Weibo ; Guzman, Raphael ; Hsu, Andrew R. ; Wang, Hui ; Chen, Kai et al
Positron Emission Tomography Imaging of Poststroke Angiogenesis
Stroke. 40(1):270-277, January 2009.
Abstract
Background and Purpose-: Vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFRs) play important roles during neurovascular repair after stroke. In this study, we imaged VEGFR expression with positron emission tomography (PET) to noninvasively analyze poststroke angiogenesis.Methods-: Female Sprague-Dawley rats after distal middle cerebral artery occlusion surgery were subjected to weekly MRI, 18F-FDG PET, and 64Cu-DOTA-VEGF121 PET scans. Several control experiments were performed to confirm the VEGFR specificity of 64Cu-DOTA-VEGF121 uptake in the stroke border zone. VEGFR, BrdU, lectin staining, and 125I-VEGF165 autoradiography on stroke brain tissue slices were performed to validate the in vivo findings.Results-: T2-weighed MRI correlated with the "cold spot" on 18F-FDG PET for rats undergoing distal middle cerebral artery occlusion surgery. The 64Cu-DOTA-VEGF121 uptake in the stroke border zone peaked at [almost equal to]10 days after surgery, indicating neovascularization as confirmed by histology (VEGFR-2, BrdU, and lectin staining). VEGFR specificity of 64Cu-DOTA-VEGF121 uptake was confirmed by significantly lower uptake of 64Cu-DOTA-VEGFmutant in vivo and intense 125I-VEGF165 uptake ex vivo in the stroke border zone. No appreciable uptake of 64Cu-DOTA-VEGF121 was observed in the brain of sham-operated rats.Conclusions-: For the first time to our knowledge, we successfully evaluated the VEGFR expression kinetics noninvasively in a rat stroke model. In vivo imaging of VEGFR expression could become a significant clinical tool to plan and monitor therapies aimed at improving poststroke angiogenesis.
Izquierdo-Garcia, David ; Davies, John R. ; Graves, Martin J. et al
Comparison of Methods for Magnetic Resonance-Guided [18-F]Fluorodeoxyglucose Positron Emission Tomography in Human Carotid Arteries: Reproducibility, Partial Volume Correction, and Correlation Between Methods.
Stroke. 40(1):86-93, January 2009.
Abstract
Background and Purpose-: Inflammation is a major risk factor for atherosclerotic plaque rupture and clinical events. Previous studies have shown that plaque [18F]fluorodeoxyglucose (FDG) uptake correlates with macrophage content. In this study we examined the reproducibility of 3 methods of quantifying plaque FDG uptake in the carotid arteries using positron emission tomography (PET). The correlation between 2 simplified uptake parameters (standardized uptake value [SUV], vessel wall-to-blood ratio [VBR]) and a gold standard technique (influx rate [Ki]) was also determined. We used MRI to correct carotid plaque FDG uptake for partial volume error.Methods-: Seven patients with a recent carotid territory transient ischemic attack underwent imaging twice within 8 days using MR and FDG-PET. MR coregistered to PET was used to delineate regions of interest, and to facilitate partial volume correction (PVC).Results-: SUV was the most reproducible parameter irrespective of whether it was normalized by body surface area (BSA), lean body mass, or weight (intraclass correlation coefficient=0.85, 0.88, and 0.90, respectively). VBR correlated better to Ki than SUV (r=0.58 VBR, r=0.46 SUVBSA). PVC improved these correlations to r=0.81 VBR and r=0.76 SUVBSA, and only slightly degraded the reproducibility of SUV (intraclass correlation coefficient=0.83-0.85).Conclusions-: MR-guided FDG-PET is a highly reproducible technique in the carotid artery and the excellent anatomic detail provided by MR facilitates PVC. Of the methods examined, SUVBSAPVC appears to represent the best compromise between reproducible and accurate determination of FDG metabolism in carotid artery vessel wall.
Showing posts with label Stroke. Show all posts
Showing posts with label Stroke. Show all posts
Friday, 2 January 2009
Friday, 3 October 2008
Articles from Stroke
Link to journal
Lansberg, Maarten G. ; Thijs, Vincent N. ; Bammer, Roland et al
The MRA-DWI Mismatch Identifies Patients With Stroke Who Are Likely to Benefit From Reperfusion
Stroke. 39(9):2491-2496, September 2008.
Abstract
Background and Purpose-: The aim of this exploratory analysis was to evaluate if a combination of MR angiography (MRA) and diffusion-weighted imaging (DWI) selection criteria can be used to identify patients with acute stroke who are likely to benefit from early reperfusion.Methods-: Data from DEFUSE, a study of 74 patients with stroke who received intravenous tissue plasminogen activator in the 3- to 6-hour time window and underwent MRIs before and approximately 4 hours after treatment were analyzed. The MRA-DWI mismatch model was defined as (1) a DWI lesion volume less than 25 mL in patients with a proximal vessel occlusion; or (2) a DWI lesion volume less than 15 mL in patients with proximal vessel stenosis or an abnormal finding of a distal vessel. Favorable clinical response was defined as an improvement on the National Institutes of Health Stroke Scale score of at least 8 points between baseline and 30 days or a National Institutes of Health Stroke Scale score <=1 at 30 days.Results-: Twenty-seven of 62 patients (44%) had an MRA-DWI mismatch. There was a differential response to early reperfusion based on MRA-DWI mismatch status. Reperfusion was associated with an increased rate of a favorable clinical response in patients with an MRA-DWI mismatch (OR, 12.5; 95% CI, 1.8 to 83.9) and a lower rate in patients without mismatch (OR, 0.2; 95% CI, 0.0 to 0.8).Conclusions-: The MRA-DWI mismatch model appears to identify patients with stroke who are likely to benefit from reperfusion therapy administered in the 3- to 6-hour time window after symptom onset. The criteria established for the MRA-DWI mismatch model in this study require validation in an independent cohort.
Puetz, Volker ; Sylaja, P N. ; Coutts, Shelagh B. ; Hill, Michael D.; et al
Extent of Hypoattenuation on CT Angiography Source Images Predicts Functional Outcome in Patients With Basilar Artery Occlusion
Stroke. 39(9):2485-2490, September 2008.
Abstract
Background and Purpose-: Quantification of early ischemic changes (EIC) may predict functional outcome in patients with basilar artery occlusion (BAO). We tested the validity of a novel CT score, the posterior circulation Acute Stroke Prognosis Early CT score (pc-ASPECTS).Methods-: Pc-ASPECTS allots the posterior circulation 10 points. Two points each are subtracted for EIC in midbrain or pons and 1 point each for EIC in left or right thalamus, cerebellum or PCA-territory, respectively. We studied 2 different populations: (1) patients with suspected vertebrobasilar ischemia and (2) patients with BAO. We applied pc-ASPECTS to noncontrast CT (NCCT), CT angiography source images (CTASI), and follow-up image by 3-reader consensus. We calculated sensitivity for ischemic changes and analyzed the predictivity of pc-ASPECTS for independent (modified Rankin Scale [mRS] score <=2) and favorable (mRS score <=3) outcome.Results-: Of 130 patients with suspected vertebrobasilar ischemia, 72% (94) had posterior circulation stroke, 8% (10) transient ischemic attack, and 20% (26) nonischemic etiology. Sensitivity for ischemic changes was improved with CTASI compared to NCCT (65% [95% CI, 57% to 73%] versus 46% [95% CI, 37% to 55%], respectively). Pc-ASPECTS score on CTASI but not NCCT predicted functional independence (OR 1.58; P=0.005 versus 1.22; P=0.42, respectively). Of 46 patients with BAO, 52% (12/23) with CTASI pc-ASPECTS score >=8 but only 4% (1/23) with a score <8>
Schellinger, Peter D. ; Kohrmann, Martin
MRA/DWI Mismatch: A Novel Concept or Something One Could Get Easier and Cheaper
Stroke. 39(9):2423-2424, September 2008.
Lansberg, Maarten G. ; Thijs, Vincent N. ; Bammer, Roland et al
The MRA-DWI Mismatch Identifies Patients With Stroke Who Are Likely to Benefit From Reperfusion
Stroke. 39(9):2491-2496, September 2008.
Abstract
Background and Purpose-: The aim of this exploratory analysis was to evaluate if a combination of MR angiography (MRA) and diffusion-weighted imaging (DWI) selection criteria can be used to identify patients with acute stroke who are likely to benefit from early reperfusion.Methods-: Data from DEFUSE, a study of 74 patients with stroke who received intravenous tissue plasminogen activator in the 3- to 6-hour time window and underwent MRIs before and approximately 4 hours after treatment were analyzed. The MRA-DWI mismatch model was defined as (1) a DWI lesion volume less than 25 mL in patients with a proximal vessel occlusion; or (2) a DWI lesion volume less than 15 mL in patients with proximal vessel stenosis or an abnormal finding of a distal vessel. Favorable clinical response was defined as an improvement on the National Institutes of Health Stroke Scale score of at least 8 points between baseline and 30 days or a National Institutes of Health Stroke Scale score <=1 at 30 days.Results-: Twenty-seven of 62 patients (44%) had an MRA-DWI mismatch. There was a differential response to early reperfusion based on MRA-DWI mismatch status. Reperfusion was associated with an increased rate of a favorable clinical response in patients with an MRA-DWI mismatch (OR, 12.5; 95% CI, 1.8 to 83.9) and a lower rate in patients without mismatch (OR, 0.2; 95% CI, 0.0 to 0.8).Conclusions-: The MRA-DWI mismatch model appears to identify patients with stroke who are likely to benefit from reperfusion therapy administered in the 3- to 6-hour time window after symptom onset. The criteria established for the MRA-DWI mismatch model in this study require validation in an independent cohort.
Puetz, Volker ; Sylaja, P N. ; Coutts, Shelagh B. ; Hill, Michael D.; et al
Extent of Hypoattenuation on CT Angiography Source Images Predicts Functional Outcome in Patients With Basilar Artery Occlusion
Stroke. 39(9):2485-2490, September 2008.
Abstract
Background and Purpose-: Quantification of early ischemic changes (EIC) may predict functional outcome in patients with basilar artery occlusion (BAO). We tested the validity of a novel CT score, the posterior circulation Acute Stroke Prognosis Early CT score (pc-ASPECTS).Methods-: Pc-ASPECTS allots the posterior circulation 10 points. Two points each are subtracted for EIC in midbrain or pons and 1 point each for EIC in left or right thalamus, cerebellum or PCA-territory, respectively. We studied 2 different populations: (1) patients with suspected vertebrobasilar ischemia and (2) patients with BAO. We applied pc-ASPECTS to noncontrast CT (NCCT), CT angiography source images (CTASI), and follow-up image by 3-reader consensus. We calculated sensitivity for ischemic changes and analyzed the predictivity of pc-ASPECTS for independent (modified Rankin Scale [mRS] score <=2) and favorable (mRS score <=3) outcome.Results-: Of 130 patients with suspected vertebrobasilar ischemia, 72% (94) had posterior circulation stroke, 8% (10) transient ischemic attack, and 20% (26) nonischemic etiology. Sensitivity for ischemic changes was improved with CTASI compared to NCCT (65% [95% CI, 57% to 73%] versus 46% [95% CI, 37% to 55%], respectively). Pc-ASPECTS score on CTASI but not NCCT predicted functional independence (OR 1.58; P=0.005 versus 1.22; P=0.42, respectively). Of 46 patients with BAO, 52% (12/23) with CTASI pc-ASPECTS score >=8 but only 4% (1/23) with a score <8>
Schellinger, Peter D. ; Kohrmann, Martin
MRA/DWI Mismatch: A Novel Concept or Something One Could Get Easier and Cheaper
Stroke. 39(9):2423-2424, September 2008.
Wednesday, 27 August 2008
Stroke. 39(6) June 2008
Link to journal
Sylaja, P N.; Coutts, Shelagh B.; Krol, Andrea; Hill, Michael D.; Demchuk, Andrew M.; for the VISION Study Group
From the Calgary Stroke Program, University of Calgary, Alberta, Canada.
When to Expect Negative Diffusion-Weighted Images in Stroke and Transient Ischemic Attack.[Letter]
p.1898-1900
Abstract
Background and Purpose-: The frequency of DWI negative cerebral ischemia and clinical factors associated with such a circumstance is not well understood.Methods-: We performed MRI including diffusion-weighted imaging (DWI) in patients with stroke and transient ischemic attack (TIA) within 24 hours of symptom onset and again at 30 days.Results-: Of 401 patients, 103 (25.6%) had an initial negative DWI study. In the DWI negative group, among the stroke patients, 6/26 (23.1%) had infarcts on follow-up MRI (4 lacunar and 2 posterior circulation syndromes) and 1 had a rMTT deficit. Among the TIA patients, 4/63 (6.3%) showed rMTT deficits and 2/63 (3.2%) had infarcts on follow-up MRI.Conclusions-: Baseline perfusion weighted imaging sequences may detect ischemia in a small proportion of DWI negative cases. Only those with brain stem location or lacunar syndrome were DWI negative initially and yet had a follow-up imaging confirmation of infarct or a final clinical diagnosis of stroke.(C) 2008 American Heart Association, Inc.
Shah, Rajiv R. ; Haghpanah, Sepideh ; Elovic, Elie P. ; Flanagan, Steven R. et al
MRI Findings in the Painful Poststroke Shoulder
p. 1808-1813
Abstract
Background and Purpose-: We describe the structural abnormalities in the painful shoulder of stroke survivors and their relationships to clinical characteristics.Method-: Eighty-nine chronic stroke survivors with poststroke shoulder pain underwent T1- and T2-weighted multiplanar, multisequence MRI of the painful paretic shoulder. All scans were reviewed by one radiologist for the following abnormalities: rotator cuff, biceps and deltoid tears, tendinopathies and atrophy, subacromial bursa fluid, labral ligamentous complex abnormalities, and acromioclavicular capsular hypertrophy. Clinical variables included subject demographics, stroke characteristics, and the Brief Pain Inventory Questions 12. The relationship between MRI findings and clinical characteristics was assessed through logistic regression.Results-: Thirty-five percent of subjects exhibited a tear of at least one rotator cuff, biceps or deltoid muscle. Fifty-three percent of subjects exhibited tendinopathy of at least one rotator cuff, bicep or deltoid muscle. The prevalence of rotator cuff tears increased with age. However, rotator cuff tears and rotator cuff and deltoid tendinopathies were not related to severity of poststroke shoulder pain. In approximately 20% of cases, rotator cuff and deltoid muscles exhibited evidence of atrophy. Atrophy was associated with reduced motor strength and reduced severity of shoulder pain.Conclusions-: Rotator cuff tears and rotator cuff and deltoid tendinopathies are highly prevalent in poststroke shoulder pain. However, their relationship to shoulder pain is uncertain. Atrophy is less common but is associated with less severe shoulder pain.(C) 2008 American Heart Association, Inc.
Sylaja, P N.; Coutts, Shelagh B.; Krol, Andrea; Hill, Michael D.; Demchuk, Andrew M.; for the VISION Study Group
From the Calgary Stroke Program, University of Calgary, Alberta, Canada.
When to Expect Negative Diffusion-Weighted Images in Stroke and Transient Ischemic Attack.[Letter]
p.1898-1900
Abstract
Background and Purpose-: The frequency of DWI negative cerebral ischemia and clinical factors associated with such a circumstance is not well understood.Methods-: We performed MRI including diffusion-weighted imaging (DWI) in patients with stroke and transient ischemic attack (TIA) within 24 hours of symptom onset and again at 30 days.Results-: Of 401 patients, 103 (25.6%) had an initial negative DWI study. In the DWI negative group, among the stroke patients, 6/26 (23.1%) had infarcts on follow-up MRI (4 lacunar and 2 posterior circulation syndromes) and 1 had a rMTT deficit. Among the TIA patients, 4/63 (6.3%) showed rMTT deficits and 2/63 (3.2%) had infarcts on follow-up MRI.Conclusions-: Baseline perfusion weighted imaging sequences may detect ischemia in a small proportion of DWI negative cases. Only those with brain stem location or lacunar syndrome were DWI negative initially and yet had a follow-up imaging confirmation of infarct or a final clinical diagnosis of stroke.(C) 2008 American Heart Association, Inc.
Shah, Rajiv R. ; Haghpanah, Sepideh ; Elovic, Elie P. ; Flanagan, Steven R. et al
MRI Findings in the Painful Poststroke Shoulder
p. 1808-1813
Abstract
Background and Purpose-: We describe the structural abnormalities in the painful shoulder of stroke survivors and their relationships to clinical characteristics.Method-: Eighty-nine chronic stroke survivors with poststroke shoulder pain underwent T1- and T2-weighted multiplanar, multisequence MRI of the painful paretic shoulder. All scans were reviewed by one radiologist for the following abnormalities: rotator cuff, biceps and deltoid tears, tendinopathies and atrophy, subacromial bursa fluid, labral ligamentous complex abnormalities, and acromioclavicular capsular hypertrophy. Clinical variables included subject demographics, stroke characteristics, and the Brief Pain Inventory Questions 12. The relationship between MRI findings and clinical characteristics was assessed through logistic regression.Results-: Thirty-five percent of subjects exhibited a tear of at least one rotator cuff, biceps or deltoid muscle. Fifty-three percent of subjects exhibited tendinopathy of at least one rotator cuff, bicep or deltoid muscle. The prevalence of rotator cuff tears increased with age. However, rotator cuff tears and rotator cuff and deltoid tendinopathies were not related to severity of poststroke shoulder pain. In approximately 20% of cases, rotator cuff and deltoid muscles exhibited evidence of atrophy. Atrophy was associated with reduced motor strength and reduced severity of shoulder pain.Conclusions-: Rotator cuff tears and rotator cuff and deltoid tendinopathies are highly prevalent in poststroke shoulder pain. However, their relationship to shoulder pain is uncertain. Atrophy is less common but is associated with less severe shoulder pain.(C) 2008 American Heart Association, Inc.
Friday, 1 August 2008
Diffusion-negative MRI in acute ischemic stroke
Diffusion-negative MRI in acute ischemic stroke: a case report
Rathakrishnan R, Sharma V, Chan B
Cases Journal, 2008 1:65 ( 29 July 2008 )
[Abstract] [Provisional PDF]
Rathakrishnan R, Sharma V, Chan B
Cases Journal, 2008 1:65 ( 29 July 2008 )
[Abstract] [Provisional PDF]
Wednesday, 18 June 2008
Stroke - online articles May 2008
Link to journal
Burgess, Richard E. ; Warach, Steven ; Schaewe, Timothy J. et al
Development and Validation of a Simple Conversion Model for Comparison of Intracerebral Hemorrhage Volumes Measured on CT and Gradient Recalled Echo MRI.
Stroke.
Publish Ahead of Print, published online before print, 15 May 2008
Abstract
Background and Purpose-: Gradient recalled echo MRI (GRE) has been shown to be as accurate as CT for the detection of acute intracerebral hemorrhage (ICH). However, because of the differences in the signal parameter being detected, apparent hemorrhage size is expected to vary by imaging modality, with GRE providing larger volumes attributable to susceptibility effects.Methods-: Image data from patients participating in 3 ICH studies were retrospectively reviewed. Patients with acute ICH were included if (1) concurrent MRI and CT were performed within 72 hours of symptom onset, and (2) each modality was performed within 240 minutes of each other. ICH volumes were calculated using a semiautomated image analysis program. The least squares method was used to develop a conversion equation based on a linear regression of GRE volume on CT volume.Results-: Thirty-six patients met inclusion criteria. MRI was performed first in 18, CT first in 18. Mean hemorrhage volume was 25.2cc (range 0.1 to 83.9cc) on CT and 32.7cc (range 0.1 to 98.7cc) measured on GRE. A linear relationship defined by CT Volume=GRE Volume*0.8 (Spearman's correlation coefficient=0.992, P<0.001) volume="0.8*GRE" r="0.83," r="0.80," ci="0.81" ci="0.70">
Mandell, Daniel M. ; Han, Jay S. ; Poublanc, Julien ; Crawley, Adrian P. et al
Mapping Cerebrovascular Reactivity Using Blood Oxygen Level-Dependent MRI in Patients With Arterial Steno-occlusive Disease: Comparison With Arterial Spin Labeling MRI.
Status Publish Ahead of Print, published online before print, 1 May 2008
Abstract Background and Purpose-: Blood oxygen level-dependent MRI (BOLD MRI) of hypercapnia-induced changes in cerebral blood flow is an emerging technique for mapping cerebrovascular reactivity (CVR). BOLD MRI signal reflects cerebral blood flow, but also depends on cerebral blood volume, cerebral metabolic rate, arterial oxygenation, and hematocrit. The purpose of this study was to determine whether, in patients with stenoocclusive disease, the BOLD MRI signal response to hypercapnia is directly related to changes in cerebral blood flow.Methods-: Thirty-eight patients with steno-occlusive disease underwent mapping of CVR by both BOLD MRI and arterial spin labeling MRI. The latter technique was used as a reference standard for measurement of cerebral blood flow changes.Results-: Hemispheric CVR measured by BOLD MRI was significantly correlated with that measured by arterial spin labeling MRI for both gray matter (R=0.83, P<0.0001) r="0.80," ci="0.81" ci="0.70">
Citation 8. Accession Number 00007670-900000000-98761. Author Freund, Wolfgang MD; Kassubek, Jan MD; Aschoff, Andrik J. MD; Huber, Roman MD; Institution From the Department of Diagnostic and Interventional Radiology (W.F., A.J.A.), University Hospitals, Ulm, Germany; and the Department of Neurology (J.K., R.H.), University of Ulm, Germany. Title MRI-Based Separation of Congenital and Acquired Vertebrobasilar Artery Anomalies in Ischemic Stroke of the Posterior Circulation.[Letter] Source Stroke. Status Publish Ahead of Print, published online before print, 5 June 2008 Abstract Background and Purpose-: Stroke MRI protocols provide useful information about underlying vessel pathologies in the anterior circulation by means of intracranial time-of-flight angiography. However, these protocols mostly fail in the posterior circulation to differentiate between congenital variants and secondary thrombosis. Therefore, a high-resolution anatomic True Fast Imaging in Steady State Precession sequence, added to a commonly used stroke imaging protocol, was evaluated.Methods-: MRIs of all emergency admissions to the stroke unit over 2 months were analyzed. Variations in the posterior circulation as displayed by time-of-flight and by the True Fast Imaging in Steady State Precession sequence, respectively, were graded by 2 readers blinded to the diagnosis.Results-: In the time-of-flight angiography, 50% of patients presented with distinctive vertebrobasilar alterations. Half of these were judged as high-grade anomalies, of which the True Fast Imaging in Steady State Precession sequence identified 25% as hypoplasia. In 40% of all patients with posterior ischemia, the True Fast Imaging in Steady State Precession sequence confirmed an acquired occlusion of the vertebrobasilar arteries.Conclusions-: The addition of an anatomic (True Fast Imaging in Steady State Precession) to a functional sequence (time-of-flight) in stroke MRI protocols enables the differentiation between artery occlusions and hypoplastic variants of the vertebral arteries.
Burgess, Richard E. ; Warach, Steven ; Schaewe, Timothy J. et al
Development and Validation of a Simple Conversion Model for Comparison of Intracerebral Hemorrhage Volumes Measured on CT and Gradient Recalled Echo MRI.
Stroke.
Publish Ahead of Print, published online before print, 15 May 2008
Abstract
Background and Purpose-: Gradient recalled echo MRI (GRE) has been shown to be as accurate as CT for the detection of acute intracerebral hemorrhage (ICH). However, because of the differences in the signal parameter being detected, apparent hemorrhage size is expected to vary by imaging modality, with GRE providing larger volumes attributable to susceptibility effects.Methods-: Image data from patients participating in 3 ICH studies were retrospectively reviewed. Patients with acute ICH were included if (1) concurrent MRI and CT were performed within 72 hours of symptom onset, and (2) each modality was performed within 240 minutes of each other. ICH volumes were calculated using a semiautomated image analysis program. The least squares method was used to develop a conversion equation based on a linear regression of GRE volume on CT volume.Results-: Thirty-six patients met inclusion criteria. MRI was performed first in 18, CT first in 18. Mean hemorrhage volume was 25.2cc (range 0.1 to 83.9cc) on CT and 32.7cc (range 0.1 to 98.7cc) measured on GRE. A linear relationship defined by CT Volume=GRE Volume*0.8 (Spearman's correlation coefficient=0.992, P<0.001) volume="0.8*GRE" r="0.83," r="0.80," ci="0.81" ci="0.70">
Mandell, Daniel M. ; Han, Jay S. ; Poublanc, Julien ; Crawley, Adrian P. et al
Mapping Cerebrovascular Reactivity Using Blood Oxygen Level-Dependent MRI in Patients With Arterial Steno-occlusive Disease: Comparison With Arterial Spin Labeling MRI.
Status Publish Ahead of Print, published online before print, 1 May 2008
Abstract Background and Purpose-: Blood oxygen level-dependent MRI (BOLD MRI) of hypercapnia-induced changes in cerebral blood flow is an emerging technique for mapping cerebrovascular reactivity (CVR). BOLD MRI signal reflects cerebral blood flow, but also depends on cerebral blood volume, cerebral metabolic rate, arterial oxygenation, and hematocrit. The purpose of this study was to determine whether, in patients with stenoocclusive disease, the BOLD MRI signal response to hypercapnia is directly related to changes in cerebral blood flow.Methods-: Thirty-eight patients with steno-occlusive disease underwent mapping of CVR by both BOLD MRI and arterial spin labeling MRI. The latter technique was used as a reference standard for measurement of cerebral blood flow changes.Results-: Hemispheric CVR measured by BOLD MRI was significantly correlated with that measured by arterial spin labeling MRI for both gray matter (R=0.83, P<0.0001) r="0.80," ci="0.81" ci="0.70">
Citation 8. Accession Number 00007670-900000000-98761. Author Freund, Wolfgang MD; Kassubek, Jan MD; Aschoff, Andrik J. MD; Huber, Roman MD; Institution From the Department of Diagnostic and Interventional Radiology (W.F., A.J.A.), University Hospitals, Ulm, Germany; and the Department of Neurology (J.K., R.H.), University of Ulm, Germany. Title MRI-Based Separation of Congenital and Acquired Vertebrobasilar Artery Anomalies in Ischemic Stroke of the Posterior Circulation.[Letter] Source Stroke. Status Publish Ahead of Print, published online before print, 5 June 2008 Abstract Background and Purpose-: Stroke MRI protocols provide useful information about underlying vessel pathologies in the anterior circulation by means of intracranial time-of-flight angiography. However, these protocols mostly fail in the posterior circulation to differentiate between congenital variants and secondary thrombosis. Therefore, a high-resolution anatomic True Fast Imaging in Steady State Precession sequence, added to a commonly used stroke imaging protocol, was evaluated.Methods-: MRIs of all emergency admissions to the stroke unit over 2 months were analyzed. Variations in the posterior circulation as displayed by time-of-flight and by the True Fast Imaging in Steady State Precession sequence, respectively, were graded by 2 readers blinded to the diagnosis.Results-: In the time-of-flight angiography, 50% of patients presented with distinctive vertebrobasilar alterations. Half of these were judged as high-grade anomalies, of which the True Fast Imaging in Steady State Precession sequence identified 25% as hypoplasia. In 40% of all patients with posterior ischemia, the True Fast Imaging in Steady State Precession sequence confirmed an acquired occlusion of the vertebrobasilar arteries.Conclusions-: The addition of an anatomic (True Fast Imaging in Steady State Precession) to a functional sequence (time-of-flight) in stroke MRI protocols enables the differentiation between artery occlusions and hypoplastic variants of the vertebral arteries.
Wednesday, 30 April 2008
Stroke - Published ahead of print
Link to journal and full text of articles
Barber, P Alan PhD, FRACP; Hach, Sylvia MSc; Tippett, Lynette J. PhD; Ross, Linda et al
Cerebral Ischemic Lesions on Diffusion-Weighted Imaging Are Associated With Neurocognitive Decline After Cardiac Surgery
Stroke. Publish Ahead of Print, published online before print, 6 March 2008
Abstract
Background and Purpose-: Improvements in cardiac surgery mortality and morbidity have focused interest on the neurological injury such as stroke and cognitive decline that may accompany an otherwise successful operation. We aimed to investigate (1) the rate of stroke, new ischemic change on MRI, and cognitive impairment after cardiac valve surgery; and (2) the controversial relationship between perioperative cerebral ischemia and cognitive decline.Methods-: Forty patients (26 men; mean [SD] age 62.1 [13.7] years) undergoing intracardiac surgery (7 also with coronary artery bypass grafting) were studied. Neurological, neuropsychological, and MRI examinations were performed 24 hours before surgery and 5 days (MRI and neurology) and 6 weeks (neuropsychology and neurology) after surgery. Cognitive decline from baseline was determined using the Reliable Change Index.Results-: Two of 40 (5%) patients had perioperative strokes and 22 of 35 (63%) tested had cognitive decline in at least one measure (range, 1 to 4). Sixteen of 37 participants (43%) with postoperative imaging had new ischemic lesions (range, 1 to 17 lesions) with appearances consistent with cerebral embolization. Cognitive decline was seen in all patients with, and 35% of those without, postoperative ischemic lesions (P<0.001),>
Tsivgoulis, Georgios MD; Alexandrov, Andrei MD;
Ultrasound-Enhanced Thrombolysis: From Bedside to Bench. [Editorial]
Stroke. Publish Ahead of Print, published online before print, 13 March 2008
Barber, P Alan PhD, FRACP; Hach, Sylvia MSc; Tippett, Lynette J. PhD; Ross, Linda et al
Cerebral Ischemic Lesions on Diffusion-Weighted Imaging Are Associated With Neurocognitive Decline After Cardiac Surgery
Stroke. Publish Ahead of Print, published online before print, 6 March 2008
Abstract
Background and Purpose-: Improvements in cardiac surgery mortality and morbidity have focused interest on the neurological injury such as stroke and cognitive decline that may accompany an otherwise successful operation. We aimed to investigate (1) the rate of stroke, new ischemic change on MRI, and cognitive impairment after cardiac valve surgery; and (2) the controversial relationship between perioperative cerebral ischemia and cognitive decline.Methods-: Forty patients (26 men; mean [SD] age 62.1 [13.7] years) undergoing intracardiac surgery (7 also with coronary artery bypass grafting) were studied. Neurological, neuropsychological, and MRI examinations were performed 24 hours before surgery and 5 days (MRI and neurology) and 6 weeks (neuropsychology and neurology) after surgery. Cognitive decline from baseline was determined using the Reliable Change Index.Results-: Two of 40 (5%) patients had perioperative strokes and 22 of 35 (63%) tested had cognitive decline in at least one measure (range, 1 to 4). Sixteen of 37 participants (43%) with postoperative imaging had new ischemic lesions (range, 1 to 17 lesions) with appearances consistent with cerebral embolization. Cognitive decline was seen in all patients with, and 35% of those without, postoperative ischemic lesions (P<0.001),>
Tsivgoulis, Georgios MD; Alexandrov, Andrei MD;
Ultrasound-Enhanced Thrombolysis: From Bedside to Bench. [Editorial]
Stroke. Publish Ahead of Print, published online before print, 13 March 2008
Alexandrov, Andrei V. MD; Mikulik, Robert MD; Ribo, Marc MD; Sharma, Vijay K. et al
A Pilot Randomized Clinical Safety Study of Sonothrombolysis Augmentation With Ultrasound-Activated Perflutren-Lipid Microspheres for Acute Ischemic Stroke
Stroke. Publish Ahead of Print, published online before print, 20 March 2008
Abstract
Background and Purpose-: Ultrasound transiently expands perflutren-lipid microspheres ([mu]S), transmitting energy momentum to surrounding fluids. We report a pilot safety/feasibility study of ultrasound-activated [mu]S with systemic tissue plasminogen activator (tPA).Methods-: Stroke subjects treated within 3 hours had abnormal Thrombolysis in Brain Ischemia (TIBI) residual flow grades 0 to 3 before tPA on transcranial Doppler (TCD). Randomization included Controls (tPA+TCD) or Target (tPA+TCD+2.8 mL [mu]S). The primary safety end point was symptomatic intracranial hemorrhage (sICH) with worsening by >=4 NIHSS points within 72 hours.Results-: Fifteen subjects were randomized 3:1 to Target, n=12 or Control, n=3. After treatment, asymptomatic ICH occurred in 3 Target and 1 Control, and sICH was not seen in any study subject. [mu]S reached MCA occlusions in all Target subjects at velocities higher than surrounding residual red blood cell flow: 39.8+/-11.3 vs 28.8+/-13.8 cm/s, P<0.001. p="0.028." p="0.003," p="0.456.Conclusions-:">
Stroke. Publish Ahead of Print, published online before print, 20 March 2008
Abstract
Background and Purpose-: Ultrasound transiently expands perflutren-lipid microspheres ([mu]S), transmitting energy momentum to surrounding fluids. We report a pilot safety/feasibility study of ultrasound-activated [mu]S with systemic tissue plasminogen activator (tPA).Methods-: Stroke subjects treated within 3 hours had abnormal Thrombolysis in Brain Ischemia (TIBI) residual flow grades 0 to 3 before tPA on transcranial Doppler (TCD). Randomization included Controls (tPA+TCD) or Target (tPA+TCD+2.8 mL [mu]S). The primary safety end point was symptomatic intracranial hemorrhage (sICH) with worsening by >=4 NIHSS points within 72 hours.Results-: Fifteen subjects were randomized 3:1 to Target, n=12 or Control, n=3. After treatment, asymptomatic ICH occurred in 3 Target and 1 Control, and sICH was not seen in any study subject. [mu]S reached MCA occlusions in all Target subjects at velocities higher than surrounding residual red blood cell flow: 39.8+/-11.3 vs 28.8+/-13.8 cm/s, P<0.001. p="0.028." p="0.003," p="0.456.Conclusions-:">
Shah, Rajiv R. MD; Haghpanah, Sepideh MD; Elovic, Elie P. MD; Flanagan, Steven R. et al
MRI Findings in the Painful Poststroke Shoulder
Stroke. Publish Ahead of Print, published online before print, 3 April 2008
Abstract
Background and Purpose-: We describe the structural abnormalities in the painful shoulder of stroke survivors and their relationships to clinical characteristics.Method-: Eighty-nine chronic stroke survivors with poststroke shoulder pain underwent T1- and T2-weighted multiplanar, multisequence MRI of the painful paretic shoulder. All scans were reviewed by one radiologist for the following abnormalities: rotator cuff, biceps and deltoid tears, tendinopathies and atrophy, subacromial bursa fluid, labral ligamentous complex abnormalities, and acromioclavicular capsular hypertrophy. Clinical variables included subject demographics, stroke characteristics, and the Brief Pain Inventory Questions 12. The relationship between MRI findings and clinical characteristics was assessed through logistic regression.Results-: Thirty-five percent of subjects exhibited a tear of at least one rotator cuff, biceps or deltoid muscle. Fifty-three percent of subjects exhibited tendinopathy of at least one rotator cuff, bicep or deltoid muscle. The prevalence of rotator cuff tears increased with age. However, rotator cuff tears and rotator cuff and deltoid tendinopathies were not related to severity of poststroke shoulder pain. In approximately 20% of cases, rotator cuff and deltoid muscles exhibited evidence of atrophy. Atrophy was associated with reduced motor strength and reduced severity of shoulder pain.Conclusions-: Rotator cuff tears and rotator cuff and deltoid tendinopathies are highly prevalent in poststroke shoulder pain. However, their relationship to shoulder pain is uncertain. Atrophy is less common but is associated with less severe shoulder pain.
MRI Findings in the Painful Poststroke Shoulder
Stroke. Publish Ahead of Print, published online before print, 3 April 2008
Abstract
Background and Purpose-: We describe the structural abnormalities in the painful shoulder of stroke survivors and their relationships to clinical characteristics.Method-: Eighty-nine chronic stroke survivors with poststroke shoulder pain underwent T1- and T2-weighted multiplanar, multisequence MRI of the painful paretic shoulder. All scans were reviewed by one radiologist for the following abnormalities: rotator cuff, biceps and deltoid tears, tendinopathies and atrophy, subacromial bursa fluid, labral ligamentous complex abnormalities, and acromioclavicular capsular hypertrophy. Clinical variables included subject demographics, stroke characteristics, and the Brief Pain Inventory Questions 12. The relationship between MRI findings and clinical characteristics was assessed through logistic regression.Results-: Thirty-five percent of subjects exhibited a tear of at least one rotator cuff, biceps or deltoid muscle. Fifty-three percent of subjects exhibited tendinopathy of at least one rotator cuff, bicep or deltoid muscle. The prevalence of rotator cuff tears increased with age. However, rotator cuff tears and rotator cuff and deltoid tendinopathies were not related to severity of poststroke shoulder pain. In approximately 20% of cases, rotator cuff and deltoid muscles exhibited evidence of atrophy. Atrophy was associated with reduced motor strength and reduced severity of shoulder pain.Conclusions-: Rotator cuff tears and rotator cuff and deltoid tendinopathies are highly prevalent in poststroke shoulder pain. However, their relationship to shoulder pain is uncertain. Atrophy is less common but is associated with less severe shoulder pain.
Wintermark, Max MD; Albers, Gregory W. MD; Alexandrov, Andrei V. MD; Alger, Jeffry R. et al Acute Stroke Imaging Research Roadmap. [Report]
Stroke. Publish Ahead of Print, published online before print, 10 April 2008
Abstract
mdash;: The recent "Advanced Neuroimaging for Acute Stroke Treatment" meeting on September 7 and 8, 2007 in Washington DC, brought together stroke neurologists, neuroradiologists, emergency physicians, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke (NINDS), the National Institute of Biomedical Imaging and Bioengineering (NIBIB), industry representatives, and members of the US Food and Drug Administration (FDA) to discuss the role of advanced neuroimaging in acute stroke treatment. The goals of the meeting were to assess state-of-the-art practice in terms of acute stroke imaging research and to propose specific recommendations regarding: (1) the standardization of perfusion and penumbral imaging techniques, (2) the validation of the accuracy and clinical utility of imaging markers of the ischemic penumbra, (3) the validation of imaging biomarkers relevant to clinical outcomes, and (4) the creation of a central repository to achieve these goals. The present article summarizes these recommendations and examines practical steps to achieve them.(C) 2008 American Heart Association, Inc.
Stroke. Publish Ahead of Print, published online before print, 10 April 2008
Abstract
mdash;: The recent "Advanced Neuroimaging for Acute Stroke Treatment" meeting on September 7 and 8, 2007 in Washington DC, brought together stroke neurologists, neuroradiologists, emergency physicians, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke (NINDS), the National Institute of Biomedical Imaging and Bioengineering (NIBIB), industry representatives, and members of the US Food and Drug Administration (FDA) to discuss the role of advanced neuroimaging in acute stroke treatment. The goals of the meeting were to assess state-of-the-art practice in terms of acute stroke imaging research and to propose specific recommendations regarding: (1) the standardization of perfusion and penumbral imaging techniques, (2) the validation of the accuracy and clinical utility of imaging markers of the ischemic penumbra, (3) the validation of imaging biomarkers relevant to clinical outcomes, and (4) the creation of a central repository to achieve these goals. The present article summarizes these recommendations and examines practical steps to achieve them.(C) 2008 American Heart Association, Inc.
Monday, 14 April 2008
Functional MRI correlates of lower limb function...
Enzinger, Christian MD; Johansen-Berg, Heidi ; Dawes, Helen PhD; Bogdanovic, Marko et al
Functional MRI Correlates of Lower Limb Function in Stroke Victims With Gait Impairment
Stroke.
Status
Publish Ahead of Print, published online before print, 13 March 2008
Abstract
Background and Purpose-: Although knowledge concerning cortical reorganization related to upper limb function after ischemic stroke is growing, similar data for lower limb movements are limited. Previous studies with hand movement suggested increasing recruitment of motor areas in the unlesioned hemisphere with increasing disability. We used ankle movement as a lower limb analog to test for similarities and differences in recovery patterns.Methods-: Eighteen subjects were selected with chronic residual gait impairment due to a single subcortical ischemic stroke. Functional MRI scans were obtained at 3.0 T during active and passive ankle dorsiflexion in the patients (8 females, 10 males; mean age, 59.9+/-13.5 years; range, 32 to 74 years) and 18 age-matched healthy control subjects.Results-: We observed substantial neocortical activity associated with foot movement both in the patients with stroke and in the healthy control subjects. Our primary finding was increased cortical activation with increasing functional impairment. The extent of activation (particularly in the primary sensorimotor cortex and the supplementary motor area of the unlesioned hemisphere) increased with disability. The changes were most prominent with the active movement task.Conclusions-: Using ankle movement, we observed increased activation in the unlesioned hemisphere associated with worse function of the paretic leg, consistent with studies on movement of paretic upper limbs. We interpret this finding as potentially adaptive recruitment of undamaged ipsilateral motor control pathways from the supplementary motor area and (possibly maladaptive) disinhibition of the ipsilateral sensorimotor cortex.
Link to journal
Functional MRI Correlates of Lower Limb Function in Stroke Victims With Gait Impairment
Stroke.
Status
Publish Ahead of Print, published online before print, 13 March 2008
Abstract
Background and Purpose-: Although knowledge concerning cortical reorganization related to upper limb function after ischemic stroke is growing, similar data for lower limb movements are limited. Previous studies with hand movement suggested increasing recruitment of motor areas in the unlesioned hemisphere with increasing disability. We used ankle movement as a lower limb analog to test for similarities and differences in recovery patterns.Methods-: Eighteen subjects were selected with chronic residual gait impairment due to a single subcortical ischemic stroke. Functional MRI scans were obtained at 3.0 T during active and passive ankle dorsiflexion in the patients (8 females, 10 males; mean age, 59.9+/-13.5 years; range, 32 to 74 years) and 18 age-matched healthy control subjects.Results-: We observed substantial neocortical activity associated with foot movement both in the patients with stroke and in the healthy control subjects. Our primary finding was increased cortical activation with increasing functional impairment. The extent of activation (particularly in the primary sensorimotor cortex and the supplementary motor area of the unlesioned hemisphere) increased with disability. The changes were most prominent with the active movement task.Conclusions-: Using ankle movement, we observed increased activation in the unlesioned hemisphere associated with worse function of the paretic leg, consistent with studies on movement of paretic upper limbs. We interpret this finding as potentially adaptive recruitment of undamaged ipsilateral motor control pathways from the supplementary motor area and (possibly maladaptive) disinhibition of the ipsilateral sensorimotor cortex.
Link to journal
Infarct volume measurements on MRI
Ay, Hakan MD; Arsava, E Murat MD; Vangel, Mark PhD; Oner, Banu MD; Zhu, Mingwang MD; Wu, Ona PhD; Singhal, Aneesh MD; Koroshetz, Walter J. MD; Sorensen, A Gregory MD;
Interexaminer Difference in Infarct Volume Measurements on MRI: A Source of Variance in Stroke Research
Stroke.
Status
Publish Ahead of Print, published online before print, 21 February 2008
Abstract
Background and Purpose-: The measurement of ischemic lesion volume on diffusion- (DWI) and perfusion-weighted MRI (PWI) is examiner dependent. We sought to quantify the variance imposed by measurement error in DWI and PWI lesion volume measurements in ischemic stroke.
Methods-: Fifty-eight consecutive patients with DWI and PWI within 12 hours of symptom onset and follow-up MRI on >= day-5 were studied. Two radiologists blinded to each other measured lesion volumes by manual outlining on each image. Interexaminer reliability was evaluated by intraclass correlation coefficients (ICC) and relative paired difference or RPD (ratio of difference between 2 measurements to their mean). The ratio of between-examiner variability to between-subject variability (variance ratio) was calculated for each imaging parameter.Results-: The correlation (ICC) between examiners ranged from 0.93 to 0.99. The median RPD was 10.0% for DWI, 14.1% for mean transit time, 18.9% for cerebral blood flow, 21.0% for cerebral blood volume, 16.8% for DWI/MTT mismatch, and 6.3% for chronic T2-weighted images. There was negative correlation between RPD and lesion volume in all but chronic T2-weighted images. The variance ratio ranged between 0.02 and 0.10.Conclusion-: Despite high correlation between volume measurements of abnormal regions on DWI and PWI by different examiners, substantial differences in individual measurements can still occur. The magnitude of variance from measurement error is primarily determined by the type of imaging and lesion volume. Minimizing this source of variance will better enable imaging to deliver on its promise of smaller sample size.
Link to journal
Interexaminer Difference in Infarct Volume Measurements on MRI: A Source of Variance in Stroke Research
Stroke.
Status
Publish Ahead of Print, published online before print, 21 February 2008
Abstract
Background and Purpose-: The measurement of ischemic lesion volume on diffusion- (DWI) and perfusion-weighted MRI (PWI) is examiner dependent. We sought to quantify the variance imposed by measurement error in DWI and PWI lesion volume measurements in ischemic stroke.
Methods-: Fifty-eight consecutive patients with DWI and PWI within 12 hours of symptom onset and follow-up MRI on >= day-5 were studied. Two radiologists blinded to each other measured lesion volumes by manual outlining on each image. Interexaminer reliability was evaluated by intraclass correlation coefficients (ICC) and relative paired difference or RPD (ratio of difference between 2 measurements to their mean). The ratio of between-examiner variability to between-subject variability (variance ratio) was calculated for each imaging parameter.Results-: The correlation (ICC) between examiners ranged from 0.93 to 0.99. The median RPD was 10.0% for DWI, 14.1% for mean transit time, 18.9% for cerebral blood flow, 21.0% for cerebral blood volume, 16.8% for DWI/MTT mismatch, and 6.3% for chronic T2-weighted images. There was negative correlation between RPD and lesion volume in all but chronic T2-weighted images. The variance ratio ranged between 0.02 and 0.10.Conclusion-: Despite high correlation between volume measurements of abnormal regions on DWI and PWI by different examiners, substantial differences in individual measurements can still occur. The magnitude of variance from measurement error is primarily determined by the type of imaging and lesion volume. Minimizing this source of variance will better enable imaging to deliver on its promise of smaller sample size.
Link to journal
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