Abstract 177: Risk of Thrombolysis-induced Hemorrhagic Transformation in Patients with Acute Ischemic Stroke: A Predictive Model Using Combined MR Perfusion Biomarkers

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Kambiz Nael ◽  
Adam H Bauer ◽  
Chelsea S Kidwell
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Roc Analysis ◽  
Cerebral Blood Volume ◽  
Optimal Parameter ◽  
Infarct Volume ◽  
Probabilistic Method ◽  
Hemorrhagic Transformation ◽  
Mr Perfusion ◽  
Multivariable Logistic Regression Model

Purpose: Hemorrhagic transformation (HT) is a potential devastating complication of thrombolysis in patients with acute ischemic stroke (AIS). The purpose of this study was to evaluate the predictive role of MR perfusion biomarkers including increased microvascular permeability (K2) and decreased cerebral blood volume (CBV) in the infarction core to predict the risk of HT in a cohort of patients with AIS who received thrombolysis. Methods: In this retrospective study, patients were included if they: had AIS, received thrombolysis, had pre-treatment MRI (including diffusion and perfusion) and had follow-up MRI for evaluation of HT within 7 days. MR perfusion data were processed employing a Bayesian probabilistic method. Using coregistered images, voxel-based K2 and rCBV values were obtained in the region of infarction (defined by ADC < 600 10 –6 mm 2 /s) and compared in patients with and without HT. Receiver operating characteristic (ROC) analysis was performed to determine the optimal parameter/s and threshold for predicting HT. Results: Forty-eight patients met study criteria: mean (SD) age was 67.5 ± 15, median baseline NIHSS was 9 (IQR: 5-24) and mean infarct volume of 34 ± 18 ml (range 11-78 ml). Thirty percent of patients (14/48) had HT. The mean K2 value was significantly ( p< . 0001) higher in patients with HT (0.24 ± 0.17) versus patients without HT (0.08 ± 0.03). Mean rCBV was significantly ( p=0 .0001) lower in patients with HT (0.21 ± 0.02) compared to patients without HT (1.28 ± 0.66). ROC analysis showed a threshold and corresponding sensitivity/specificity of 0.104, 94%/84% for K2 and 0.38, 94/97% for rCBV. The combination of K2 and rCBV resulted in a higher discriminative power with an AUC of 0.97, sensitivity of 94% and specificity of 100%. In a multivariable logistic regression model that included NIHSS and infarct volume, the combined K2-rCBV classifier was an independent predictor of HT. Conclusion: Combined increased permeability and decreased CBV derived from MR perfusion have improved sensitivity and specificity, compared to either measure alone, for prediction of HT following thrombolysis. A larger clinical study is required to validate our results in an independent cohort.

Abstract 3681: Early Anticoagulation Is Not Associated With Hemorrhagic Transformation Of Ischemic Stroke In Patients With Atrial Fibrillation

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
H. B Brouwers ◽  
Svetlana Lorenzano ◽  
Lyndsey H Starks ◽  
David M Greer ◽  
Steven K Feske ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Clinical Data ◽  
Infarct Volume ◽  
Hemorrhagic Transformation ◽  
P Value ◽  
Long Term Outcome ◽  
Nihss Score

Purpose: Hemorrhagic transformation (HT) is a common and potentially devastating complication of ischemic stroke, however its prevalence, predictors, and outcome remain unclear. Early anticoagulation is thought to be a risk factor for HT which raises the clinical question when to (re)start anticoagulation in ischemic stroke patients who have a compelling indication, such as atrial fibrillation. We conducted a prospective cohort study to address this question and to identify association of hemorrhagic transformation with outcome measures in patients with atrial fibrillation in the setting of acute ischemic stroke. Materials and Methods: We performed a prospective study which enrolled consecutive patients admitted with acute ischemic stroke presenting to a single center over a three-year period. As part of the observational study, baseline clinical data and stroke characteristics as well as 3 month functional outcome were collected. For this sub-study, we restricted the analysis to subjects diagnosed with atrial fibrillation. CT and MRI scans were reviewed by experienced readers, blinded to clinical data, to assess for hemorrhagic transformation (using ECASS 2 criteria), microbleeds and infarct volumes in both admission and follow-up scans. Clinical and outcome data were analyzed for association with hemorrhagic transformation. Results: Of 94 patients, 63 had a history of atrial fibrillation (67.0%) and 31 had newly discovered atrial fibrillation (33.0%). We identified HT in 3 of 94 baseline scans (3.2%) and 22 of 48 follow-up scans (45.8%) obtained a median of 3 days post-stroke. In-hospital initiation of either anti-platelet (n = 36; OR 0.34 [95% CI 0.10-1.16], p-value = 0.09) or anticoagulation with unfractionated intravenous heparin or low molecular weight heparin (n = 72; OR 0.25 [95% CI 0.06-1.15], p-value = 0.08) was not associated with HT. Initial NIH Stroke Scale (NIHSS) score (median 13.0 [IQR 15.0] vs. 7.0 [IQR 10.0], p-value = 0.029) and baseline infarct volume (median 17 [IQR 42.03] vs. 5 [IQR 10.95], p-value = 0.011) were significantly higher in patients with HT compared to those without. Hemorrhagic transformation was associated with a significantly higher 48-hour median NIHSS score (20 [IQR 3.0] vs. 2 [IQR 3.25], p-value = 0.007) and larger final infarct volume (81.40 [IQR 82.75] vs. 9.95 [IQR 19.73], p-value < 0.001). Finally, we found a trend towards poorer 3-month modified Rankin Scale scores in subjects with HT (OR 11.25 [95% CI 0.97-130.22], p-value = 0.05). Conclusion: In patients with atrial fibrillation, initial NIHSS score and baseline infarct volume are associated with hemorrhagic transformation in acute ischemic stroke. Early initiation of antithrombotic therapy was not associated with hemorrhagic transformation. Patients with hemorrhagic transformation were found to have a poorer short and long term outcome and larger final infarct volumes.

Abstract P12: Alteplase Reduces Mortality in Patients With Ischemic Stroke and Atrial Fibrillation: Analysis of the IAC Study

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Shadi Yaghi ◽  
Eva Mistry ◽  
Adam H De Havenon ◽  
Christopher Leon Guerrero ◽  
Amre Nouh ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Infarct Volume ◽  
Intravenous Thrombolysis ◽  
The United States ◽  
Hemorrhagic Transformation ◽  
Stroke Patients ◽  
Increased Risk ◽  
Significant Difference

Background and Purpose: Multiple studies have established that intravenous thrombolysis with alteplase improves outcome after acute ischemic stroke. However, assessment of thrombolysis’ efficacy in stroke patients with atrial fibrillation (AF) has yielded mixed results. We sought to determine the association of alteplase with mortality, hemorrhagic transformation (HT), infarct volume, and mortality in patients with AF and acute ischemic stroke. Methods: We retrospectively analyzed consecutive acute ischemic stroke patients with AF included in the Initiation of Anticoagulation after Cardioembolic stroke (IAC) study, which pooled data from 8 comprehensive stroke centers in the United States. 1889 (90.6%) had available 90-day follow up data and were included. For our primary analysis we used a cohort of 1367/1889 (72.4%) patients who did not undergo mechanical thrombectomy (MT). Secondary analyses were repeated in the patients that underwent MT (n=522). Binary logistic regression was used to determine whether alteplase use was independently associated with risk of HT, final infarct volume, and 90-day mortality, respectively, adjusting for potential confounders. Results: In our primary analyses we found that alteplase use was independently associated with an increased risk for HT (adjusted OR 2.14, 95% CI 1.49 - 3.07, p <0.001) but overall reduced risk of 90-day mortality (adjusted OR 0.58, 95% CI 0.39 - 0.87, p = 0.009). Among patients undergoing MT, alteplase use was associated with a trend towards a reduction in 90-day mortality (adjusted OR 0.68 95% CI 0.45 - 1.04, p = 0.077). In the subgroup of patients prescribed DOAC treatment (n = 327; 24 received alteplase), alteplase treatment was associated with a trend towards smaller infarct size (< 10 mL), (adjusted OR 0.40, 95% CI 0.15 - 1.12, p = 0.082) without a significant difference in the odds of 90-day mortality (adjusted OR 0.51, 95% CI 0.12 - 2.13, p = 0.357) or hemorrhagic transformation (adjusted OR 0.27, 95% CI 0.03 - 2.07, p = 0.206). Conclusion: Thrombolysis with intravenous alteplase was associated with reduced 90-day mortality in AF patients with acute ischemic stroke not undergoing MT. Further study is required to assess the safety and efficacy of alteplase in AF patients undergoing MT and those on DOACs.

Abstract TP315: D-dimer is Associated With 30-day Mortality in Acute Ischemic Stroke With Active Cancer

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Ki Woong Nam ◽  
Chi Kyung Kim ◽  
Tae Jung Kim ◽  
Sang Joon An ◽  
Kyungmi Oh ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Infarct Volume ◽  
Hemorrhagic Transformation ◽  
Stroke Patients ◽  
Nihss Score ◽  
Patients With Cancer ◽  
Advanced Stages ◽  
D Dimer ◽  
Active Cancer

Background: Stroke in cancer patients is not rare, but is a devastating event with high mortality. However, the predictors of mortality in stroke patients with cancer have not been well addressed. D-dimer could be a useful predictor because it can reflect both thromboembolic events and advanced stages of cancer. In this study, we evaluate the possibility of D-dimer as a predictor of 30-day mortality in stroke patients with active cancer. Methods: We included 210 ischemic stroke patients with active cancer. The data of 30-day mortality were collected by reviewing medical records. We also collected follow-up D-dimer levels in 106 (50%) participants to evaluate the effects of treatment response on D-dimer levels. Results: Of the 210 participants, 30-day mortality occurred in 28 (13%) patients. Higher initial NIHSS score, D-dimer levels, CRP levels, frequent cryptogenic mechanism, systemic metastasis, multiple vascular territory lesion, hemorrhagic transformation, and larger infarct volume were related to 30-day mortality. In the multivariate analysis, D-dimer [adjusted OR (aOR) = 2.19; 95% CI, 1.46-3.28, P < 0.001] predicted 30-day mortality after adjusting for confounders. Initial NIHSS score (aOR = 1.07; 95% CI, 1.00-1.14, P = 0.043) and hemorrhagic transformation (aOR = 3.02; 95% CI, 1.10-8.29, P = 0.032) were also significant independently from D-dimer levels. In the analysis of D-dimer changes after treatment, the mortality group showed no significant decrease of D-dimer levels, despite treatment, while the survivor group showed opposite responses. Conclusions: D-dimer levels may predict 30-day mortality in acute ischemic stroke patients with active cancer.

Abstract P348: Perfusion Collateral Index vs. Hypoperfusion Intensity Ratio in Assessment of Angiographic Collateral Scores in Patients With Acute Ischemic Stroke

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Brian Tsui ◽  
Iris Chen ◽  
Joe Qiao ◽  
Kasra Khatibi ◽  
Lucido Ponce Mejia ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Perfusion Imaging ◽  
Intensity Ratio ◽  
Roc Analysis ◽  
Cerebral Blood Volume ◽  
Imaging Biomarker ◽  
Lesion Volume ◽  
Significant Difference ◽  
Sensitivity Specificity

Background and Purpose: In acute ischemic stroke (AIS), perfusion imaging, while not directly visualizing collateral vessels, can provide important insight into collateral robustness, indexed by perfusion lesion volume and by perfusion lesion heterogeneity. Two proposed perfusion lesion heterogeneity measures indexing collateral status are the Perfusion Collateral Index (PCI) and Hypoperfusion Intensity Ratio (HIR), but their accuracy compared with direct collateral assessment on DSA has been incompletely characterized. Methods: Consecutive AIS patients with anterior circulation large vessel occlusion who underwent pre-endovascular thrombectomy MRI perfusion imaging were included. MRI measures analyzed were: 1) Perfusion Collateral Index ( PCI) - the volume of moderately hypoperfused tissue (arterial tissue delay time between 2 and 6 seconds: ATD 2-6sec ) multiplied by its corresponding relative cerebral blood volume using Olea software; 2) Hypoperfusion Intensity Ratio (HIR) ratio of moderate TMax >6 s lesion volume versus severe Tmax >10 s lesion volume with the RAPID software program. DSA collateral scores were evaluated by ASITN grading and dichotomized to inadequate (ASTIN <2) vs. adequate (ASTIN ≥3). Results: Among 48 patients meeting entry criteria, age (mean ± SD) was 70 (± 15.2), 54% were female, and NIHSS (median, IQR) was 15 (10-19). For HIR, there was no significant difference in score values in patients with adequate vs inadequate collaterals: 0.35 ± 0.20 vs 0.39 ± 0.25, p=0.68. ROC analysis using previously described cut-off of 0.4 resulted in an AUC of 0.52 and sensitivity/specificity of 71% / 33%. For PCI, score values were significantly higher in patients with adequate vs inadequate collaterals, 117 ± 61 vs. 57 ± 41, p=0.002. ROC analysis using previously described cut-off of 62 resulted in an AUC of 0.8 and sensitivity/specificity of 84% / 78%. Conclusion: Collateral status can be accurately assessed on perfusion MRI with the Perfusion Collateral Index, which outperformed the Hypoperfusion Intensity Ratio. MRI-PCI is an informative imaging biomarker of collateral status in patients with AIS.

Abstract WMP17: Computerized Tomography Perfusion to Characterize Lack of Clinical Improvement After Recanalization in Acute Ischemic Stroke

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Alvaro Garcia-Tornel ◽  
Marta Olive-Gadea ◽  
Marc Ribo ◽  
David Rodriguez-Luna ◽  
Jorge Pagola ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Functional Outcome ◽  
Infarct Volume ◽  
Significant Proportion ◽  
Hemorrhagic Transformation ◽  
Vessel Occlusion ◽  
Clinical Recovery ◽  
Good Functional Outcome ◽  
Significant Difference

A significant proportion of patients with acute ischemic stroke (AIS) treated with endovascular thrombectomy (EVT) present poor functional outcome despite recanalization. We aim to investigate computed tomography perfusion (CTP) patterns after EVT and their association with outcome Methods: Prospective study of anterior large vessel occlusion AIS patients who achieved complete recanalization (defined as modified Thrombolysis in Cerebral Ischemia (TICI) 2b - 3) after EVT. CTP was performed within 30 minutes post-EVT recanalization (POST-CTP): hypoperfusion was defined as volume of time to maximal arrival of contrast (Tmax) delay ≥6 seconds in the affected territory. Hyperperfusion was defined as visual increase in cerebral blood flow (CBF) and volume (CBV) with advanced Tmax compared with the unaffected hemisphere. Dramatic clinical recovery (DCR) was defined as a decrease of ≥8 points in NIHSS score at 24h or NIHSS≤2 and good functional outcome by mRS ≤2 at 3 months. Results: One-hundred and forty-one patients were included. 49 (34.7%) patients did not have any perfusion abnormality on POST-CTP, 60 (42.5%) showed hypoperfusion (median volume Tmax≥6s 17.5cc, IQR 6-45cc) and 32 (22.8%) hyperperfusion. DCR appeared in 56% of patients and good functional outcome in 55.3%. Post-EVT hypoperfusion was related with worse final TICI, and associated worse early clinical evolution, larger final infarct volume (p<0.01 for all) and was an independent predictor of functional outcome (OR 0.98, CI 0.97-0.99, p=0.01). Furthermore, POST-CTP identified patients with delayed improvement: in patients without DCR (n=62, 44%), there was a significant difference in post-EVT hypoperfusion volume according to functional outcome (hypoperfusion volume of 2cc in good outcome vs 11cc in poor outcome, OR 0.97 CI 0.93-0.99, p=0.04), adjusted by confounding factors. Hyperperfusion was not associated with worse outcome (p=0.45) nor symptomatic hemorrhagic transformation (p=0.55). Conclusion: Hypoperfusion volume after EVT is an accurate predictor of functional outcome. In patients without dramatic clinical recovery, hypoperfusion predicts good functional outcome and defines a “stunned-brain” pattern. POST-CTP may help to select EVT patients for additional therapies.

Abstract T P26: Combining Clinical and Imaging Data to Develop a Highly Predictive Model of Outcomes in the MR RESCUE Trial

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Chelsea S Kidwell ◽  
Reza Jahan ◽  
Jeffrey Gornbein ◽  
Jeffry R Alger ◽  
Val Nenov ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Infarct Volume ◽  
Patient Characteristics ◽  
Hemorrhagic Transformation ◽  
Imaging Data ◽  
Vascular Events ◽  
Vessel Occlusion ◽  
Intermediate Variables ◽  
Core Volume

Background: Identifying patient characteristics that predict outcomes in acute ischemic stroke may assist in triaging those who are candidates for endovascular therapies. We sought to identify predictors of outcome in the overall Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE) cohort and compare results to the previously validated Totaled Health Risks in Vascular Events (THRIVE) score. Methods: MR RESCUE randomized 118 acute ischemic stroke patients with multimodal imaging to embolectomy or standard care within 8 hours of onset. For this analysis, we investigated 17 baseline variables (e.g. age, predicted core volume, time to enrollment) and 8 intermediate variables (e.g. hemorrhagic transformation, day 7 recanalization, final infarct volume) with the potential to impact outcomes (day 90 mRS). The baseline variables were analyzed employing bivariate and multivariate methods (random forest and logistic regression). Two models were developed, one including only significant baseline variables, and the second also incorporating significant intermediate variables. Results: A multivariate model (Table) employing only baseline covariates achieved an overall accuracy (C statistic) of 85% in predicting poor outcome (day 90 mRS 3-6) compared to 80.5% for the THRIVE score. A second model (Table) adding significant intermediate variables achieved 89% accuracy in predicting day 90 mRS. Conclusions: In the MR RESCUE trial, advanced imaging variables, including predicted core volume and site of vessel occlusion, contributed to a highly accurate multivariable model of outcome. In the development phase, this model achieved higher accuracy than the THRIVE score. Future studies are needed to validate this model in an independent cohort.

NADPH oxidase inhibitor regulates microRNAs with improved outcome after mechanical reperfusion

2016 ◽  
Vol 9 (7) ◽  
pp. 702-706 ◽  
Author(s):  
Zhong Liu ◽  
Yong-Hua Tuo ◽  
Jian-Wen Chen ◽  
Qing-Yuan Wang ◽  
Songlin Li ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Nadph Oxidase ◽  
Acute Ischemic Stroke ◽  
Infarct Volume ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Hemorrhagic Transformation ◽  
Oxidase Inhibitor ◽  
Rt Pcr ◽  
Stroke Treatment ◽  
Microrna Microarray

BackgroundInhibition of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) pathway improves the neurological outcome in the transient middle cerebral artery occlusion (tMCAO) animal model. In this study we analyzed the microRNAs profile targeting NOX2 and NOX4 genes and its response to NOX2/4 inhibitor VAS2870 to understand the mechanisms of this protective effect.MethodsThe intraluminal filament tMCAO model was established in hyperglycemic rats (n=106) with 5 hours ischemia followed by 19 hours reperfusion. NOX inhibitor VAS2870 was delivered intravenously before reperfusion. Infarct volume, hemorrhagic transformation, and mortality were determined at 24 hours after cerebral ischemia. MicroRNAs profile targeting NOX2 and NOX4 genes were predicted by microRNA databases and further evaluated by microRNA microarray and quantitative RT-PCR.ResultsTen microRNAs potentially targeting NOX2 and NOX4 genes (including microRNA-29a, microRNA-29c, microRNA-126a, microRNA-132, microRNA-136, microRNA-138, microRNA-139, microRNA-153, microRNA-337, and microRNA-376a) were significantly downregulated in the ischemic hemisphere in the tMCAO group compared with the sham-operated group, as shown by microRNA microarray and quantitative RT-PCR (all p<0.05). Intravenous treatment with NOX inhibitor VAS2870 before reperfusion increased the expression of microRNA-29a, microRNA-29c, microRNA-126a, and microRNA-132 compared with the tMCAO group (all p<0.05).ConclusionsSeveral microRNAs potentially targeting NOX2 and NOX4 genes displayed altered levels in hyperglycemic rats with the tMCAO model, suggesting their regulatory roles and targeting potentials for acute ischemic stroke treatment. Targeting specific microRNAs may represent a novel intervention opportunity to improve outcome and reduce hemorrhagic transformation after mechanical reperfusion for acute ischemic stroke.

scholarly journals Targets of vascular protection in acute ischemic stroke differ in type 2 diabetes

2013 ◽  
Vol 304 (6) ◽  
pp. H806-H815 ◽  
Author(s):  
Aisha I. Kelly-Cobbs ◽  
Roshini Prakash ◽  
Weiguo Li ◽  
Bindu Pillai ◽  
Sherif Hafez ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Infarct Volume ◽  
Hemorrhagic Transformation ◽  
Artery Occlusion ◽  
Neurological Deficits ◽  
Diabetic Patients ◽  
Vascular Protection ◽  
Acute Therapy

Hemorrhagic transformation is an important complication of acute ischemic stroke, particularly in diabetic patients receiving thrombolytic treatment with tissue plasminogen activator, the only approved drug for the treatment of acute ischemic stroke. The objective of the present study was to determine the effects of acute manipulation of potential targets for vascular protection [i.e., NF-κB, peroxynitrite, and matrix metalloproteinases (MMPs)] on vascular injury and functional outcome in a diabetic model of cerebral ischemia. Ischemia was induced by middle cerebral artery occlusion in control and type 2 diabetic Goto-Kakizaki rats. Treatment groups received a single dose of the peroxynitrite decomposition catalyst 5,10,15,20-tetrakis(4-sulfonatophenyl)prophyrinato iron (III), the nonspecific NF-κB inhibitor curcumin, or the broad-spectrum MMP inhibitor minocycline at reperfusion. Poststroke infarct volume, edema, hemorrhage, neurological deficits, and MMP-9 activity were evaluated. All acute treatments reduced MMP-9 and hemorrhagic transformation in diabetic groups. In addition, acute curcumin and minocycline therapy reduced edema in these animals. Improved neurological function was observed in varying degrees with treatment, as indicated by beam-walk performance, modified Bederson scores, and grip strength; however, infarct size was similar to untreated diabetic animals. In control animals, all treatments reduced MMP-9 activity, yet bleeding was not improved. Neuroprotection was only conferred by curcumin and minocycline. Uncovering the underlying mechanisms contributing to the success of acute therapy in diabetes will advance tailored stroke therapies.

scholarly journals MR Perfusion and Diffusion in Acute Ischemic Stroke: Human Gray and White Matter have Different Thresholds for Infarction

2005 ◽  
Vol 25 (10) ◽  
pp. 1280-1287 ◽  
Author(s):  
Michael S Bristow ◽  
Jessica E Simon ◽  
Robert A Brown ◽  
Michael Eliasziw ◽  
Michael D Hill ◽  
...  
Keyword(s):  
At Risk ◽  
Ischemic Stroke ◽  
White Matter ◽  
Acute Ischemic Stroke ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Mr Perfusion ◽  
Tissue Specific ◽  
Specific Analysis ◽  
And Diffusion

It is thought that gray and white matter (GM and WM) have different perfusion and diffusion thresholds for cerebral infarction in humans. We sought to determine these thresholds with voxel-by-voxel, tissue-specific analysis of coregistered acute and follow-up magnetic resonance (MR) perfusion- and diffusion-weighted imaging. Quantitative cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and apparent diffusion coefficient (ADC) maps were analyzed from nine acute stroke patients (imaging acquired within 6 h of onset). The average values of each measure were calculated for GM and WM in normally perfused tissue, the region of recovered tissue and in the final infarct. Perfusion and diffusion thresholds for infarction were determined on a patient-by-patient basis in GM and WM separately by selecting thresholds with equal sensitivities and specificities. Gray matter has higher thresholds for infarction than WM ( P<0.009) for CBF (20.0 mL/100 g min in GM and 12.3 mL/100 g min in WM), CBV (2.4 mL/100 g in GM and 1.7 mL/100 g in WM), and ADC (786 × 10−6 mm2/s in GM and 708 × 10−6 mm2/s in WM). The MTT threshold for infarction in GM is lower ( P = 0.014) than for WM (6.8 secs in GM and 7.1 secs in WM). A single common threshold applied to both tissues overestimates tissue at risk in WM and underestimates tissue at risk in GM. This study suggests that tissue-specific analysis of perfusion and diffusion imaging is required to accurately predict tissue at risk of infarction in acute ischemic stroke.

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