scholarly journals Clinically Meaningful MRI Perfusion Abnormalities in Acute Stroke: Comparison of Analytic Techniques

Stroke ◽  
2001 ◽  
Vol 32 (suppl_1) ◽  
pp. 339-339
Author(s):  
Chen-Sen Wu ◽  
Lawrence L Latour ◽  
Steven Warach
Keyword(s):  
At Risk ◽  
Acute Stroke ◽  
Moment Method ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Clinical Severity ◽  
Perfusion Parameter ◽  
Time Curve ◽  
Time To Peak ◽  
First Moment

P2 Background: MRI perfusion imaging (PWI) can demonstrate hemodynamic abnormalities in acute stroke. The volume of hypoperfusion derived from calculated perfusion parameter maps has been used to predict tissue at risk for infarction and to identify presumptive ischemic penumbra. It is unclear how best to distinguish true tissue at risk from benign hypoperfusion. A first step toward this goal is identifying clinically significant PWI abnormalities in stroke patients. Our purpose was to evaluate four different perfusion parameter maps to determine which algorithm best correlates with clinical severity. Methods: Twenty patients were retrospectively selected from our database. Selection criteria included 1) acute hemispheric lesion, 2) MRI within 24 hours of symptom onset, and 3) no history of prior stroke. Perfusion maps were derived using four different algorithms to estimate relative mean transit time (rMTT): 1) cerebral blood volume (CBV) / cerebral blood flow (CBF), 2) CBV / peak of the concentration-time curve, 3) time to peak (TTP), and 4) ratio of the 1 st / 0 th moment of the transfer function (first moment method). Abnormal perfusion volumes were derived from ever-increasing thresholds of rMTT delay relative to normal contralateral tissue. The volumes at each delay threshold were correlated with National Institutes of Health Stroke Scale (NIHSS) for each algorithm. Results: Significant correlations between hypoperfusion volumes and NIHSS were found for all algorithms. The first moment method had the highest correlation (r = 0.76) and the correlations for this method were independent of the delay threshold used to derive the volumes. For the other algorithms, the best correlations were observed for volumes including only voxels with delays of 4 seconds or greater. Conclusions: This analysis suggests that the first moment method may have advantages over the others in determining the correlation of hypoperfusion volume to NIHSS. Further analyses correlating acute hypoperfusion volumes to final infarct volumes may help refine the choice of best analytic method for determining clinically relevant PWI abnormalities.

Is Perfusion MRI without Deconvolution Reliable for Mismatch Detection in Acute Stroke? Validation with 15O-Positron Emission Tomography

2018 ◽  
Vol 46 (1-2) ◽  
pp. 16-23 ◽  
Author(s):  
Johanna Reimer ◽  
Cornelia Montag ◽  
Alexander Schuster ◽  
Walter Moeller-Hartmann ◽  
Jan Sobesky ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
At Risk ◽  
Acute Stroke ◽  
Characteristic Curve ◽  
Area Under The Curve ◽  
Treatment Decisions ◽  
Emission Tomography ◽  
Time To Peak ◽  
Positron Emission ◽  
First Moment

Background: In acute stroke, the magnetic resonance (MR) imaging-based mismatch concept is used to select patients with tissue at risk of infarction for reperfusion therapies. There is however a controversy if non-deconvolved or deconvolved perfusion weighted (PW) parameter maps perform better in tissue at risk prediction and which parameters and thresholds should be used to guide treatment decisions. Methods: In a group of 22 acute stroke patients with consecutive MR and quantitative positron emission tomography (PET) imaging, non-deconvolved parameters were validated with the gold standard for penumbral-flow (PF) detection 15O-water PET. Performance of PW parameters was assessed by a receiver operating characteristic curve analysis to identify the accuracy of each PWI map to detect the ­upper PF threshold as defined by PET cerebral blood flow <20 mL/100 g/min. Results: Among normalized non-deconvolved parameters, PW-first moment without delay correction (FM without DC) > 3.6 s (area under the curve [AUC] = 0.89, interquartile range [IQR] 0.85–0.94), PW-maximum of the concentration curve (Cmax) < 0.66 (AUC = 0.92, IQR 0.84–0.96) and PW-time to peak (TTP) > 4.0 s (AUC = 0.92, IQR 0.87–0.94) perform significantly better than other non-deconvolved parameters to detect the PF threshold as defined by PET. Conclusions: Non-deconvolved parameters FM without DC, Cmax and TTP are an observer-independent alternative to established deconvolved parameters (e.g., Tmax) to guide treatment decisions in acute stroke.

scholarly journals Spatial Distribution of Perfusion Abnormality in Acute MCA Occlusion is Associated with Likelihood of Later Recanalization

2014 ◽  
Vol 34 (5) ◽  
pp. 813-819 ◽  
Author(s):  
Susanne Siemonsen ◽  
Nils Daniel Forkert ◽  
Anne Hansen ◽  
Andre Kemmling ◽  
Götz Thomalla ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Three Dimensional ◽  
Area Under The Curve ◽  
Fibrinolytic Therapy ◽  
Data Sets ◽  
Infarct Core ◽  
Compensatory Mechanisms ◽  
Time To Peak

The aim of this study is to investigate whether different spatial perfusion-deficit patterns, which indicate differing compensatory mechanisms, can be recognized and used to predict recanalization success of intravenous fibrinolytic therapy in acute stroke patients. Twenty-seven acute stroke data sets acquired within 6 hours from symptom onset including diffusion- (DWI) and perfusion-weighted magnetic resonance (MR) imaging (PWI) were analyzed and dichotomized regarding recanalization outcome using time-of-flight follow-up data sets. The DWI data sets were used for calculation of apparent diffusion coefficient (ADC) maps and subsequent infarct core segmentation. A patient-individual three-dimensional (3D) shell model was generated based on the segmentation and used for spatial analysis of the ADC as well as cerebral blood volume (CBV), cerebral blood flow, time to peak (TTP), and mean transit time (MTT) parameters derived from PWI. Skewness, kurtosis, area under the curve, and slope were calculated for each parameter curve and used for classification (recanalized/nonrecanalized) using a LogitBoost Alternating Decision Tree (LAD Tree). The LAD tree optimization revealed that only ADC skewness, CBV kurtosis, and MTT kurtosis are required for best possible prediction of recanalization success with a precision of 85%. Our results suggest that the propensity for macrovascular recanalization after intravenous fibrinolytic therapy depends not only on clot properties but also on distal microvascular bed perfusion. The 3D approach for characterization of perfusion parameters seems promising for further research.

Abstract TP152: Computed Tomography Perfusion Parameter to Predict Cerebral Hyperperfusion Phenomenon Following Carotid Artery Stenting

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Yoichiro Takahashi ◽  
Takahisa Mori ◽  
Tomonori Iwata ◽  
Yuichi Miyazaki ◽  
Masahito Nakazaki ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Carotid Artery Stenting ◽  
Cerebral Blood Volume ◽  
Ct Perfusion ◽  
Mean Transit Time ◽  
Perfusion Parameter ◽  
Unaffected Side ◽  
Time To Peak ◽  
Cerebral Hyperperfusion ◽  
Ratio Change

Background: Although SPECT is useful for predicting and finding cerebral hyperperfusion phenomenon (CHP) following carotid artery stenting (CAS), there are few institutions that could perform SPECT during peri-CAS period. The purpose of our study is to evaluate whether or not parameters derived from CT perfusion (CTP) used widely can predict CHP. Methods: Patients who underwent CTP before elective CAS and SPECT before and immediately after elective CAS in our institution from December 2010 to May 2012. We defined CHP as post-CAS increase of more than 10% of the ratio of cerebral blood flow (CBF) in the territory of the affected middle cerebral artery (MCA) divided by CBF in the ipsilateral cerebellum (MCA/CE ratio) measured by SPECT. We assessed the correlation of pre-CAS CTP’s parameters’ ratio to MCA/CE ratio change between pre-CAS and post-CAS SPECT. The CTP’s parameters’ ratio was calculated as (parameters in the affected side divided by in the unaffected side). CTP parameters we assessed are as follows: time-to-peak (TTP), mean-transit-time (MTT), cerebral blood volume (CBV) and CBF. Results: Fifty patients were analyzed. Pre-CAS TTP ratio showed a significant positive correlation with MCA/CE ratio change (r = 0.2863, p = 0.044). Other parameters (MTT, CBV and CBF) had no significant correlation. The cut-off value of pre-CAS TTP ratio was 1.08 to predict CHP (AUC = 0.77859, p = 0.032). Conclusion: Increase of pre-CAS TTP ratio is probably correlated with CHP following elective CAS.

scholarly journals Clinical and Radiological Correlates of Reduced CBF Measured Using MRI

Stroke ◽  
2001 ◽  
Vol 32 (suppl_1) ◽  
pp. 317-318
Author(s):  
Vincent N Thijs ◽  
Tobias Neumann-Haefelin ◽  
Michael E Moseley ◽  
Michael P Marks ◽  
Gregory W Albers
Keyword(s):  
Symptom Onset ◽  
Cerebral Blood Volume ◽  
Arterial Input Function ◽  
Mean Transit Time ◽  
Input Function ◽  
Lesion Volume ◽  
Time Curve ◽  
Measured Concentration ◽  
Ischemic Lesion ◽  
Adc Values

11 Background and purpose Methods for determining CBF using IV bolus tracking MRI have recently become available. Reduced apparent diffusion coefficient (ADC) values of brain tissue are associated with reductions in regional cerebral blood flow (rCBF). We studied the clinical and radiological features of patients with severe reductions of rCBF on MRI and analysed the relationship between reduced rCBF and ADC. Methods We studied patients with non-lacunar acute ischemic stroke in whom PWI and DWI MRI were performed within 7 hours after symptom onset. A PWI>DWI mismatch of >20% was required. Maps of rCBF, cerebral blood volume (rCBV) and mean transit time (rMTT) were generated after deconvoluting the measured concentration-time curve with the arterial input function using singular value decomposition. The ischemic lesion was outlined on the MTT map and the region of interest (ROI) transferred to the rCBF and rCBV map. ADC-maps were calculated. ADC lesions were defined as regions with ADC values ≤ 550 μm m2/sec. We compared the characteristics of patients with ischemic lesions that had a relative CBF of <50% to the contralateral hemisphere to patients with lesions that had relative CBF of >50%. Characteristics analysed included age, time to MRI, baseline NIHSS, mean ADC, DWI lesion volume, PWI lesion volume and absolute mismatch volume. Results Fifteen patients with an initial PWI>DWI mismatch of >20% were included. Ten had lesions with rCBF of >50% (median 60%) and five patients had rCBF of <50% (median 27.7%). Patients with rCBF <50% had lower ADC values (median 431 μmm2/sec versus 506 μ mm2/sec, p=0.028), larger DWI volumes (median 75.6 cm 3 versus 8.6 cm 3 , p=0.001) and larger PWI lesions as defined by the MTT volume (median 193 cm 3 versus 69 cm 3 , p=0.028) and more severe baseline NIHSS scores (median 18 versus 9, p=0.019). The rMTT and rCBV of the lesions were similar in both groups, as were the age, the absolute mismatch volume and the time from symptom onset to MRI. Conclusion These data indicate that ischemic lesions with severe CBF reductions, measured with new MRI techniques, are associated with a lower mean ADC, larger DWI and PWI lesion volumes and a higher NIHSS score.

Dexamethasone and Enhancing Solitary Cerebral Mass Lesions: Alterations in Perfusion and Blood-tumor Barrier Kinetics Shown by Magnetic Resonance Imaging

Neurosurgery ◽  
2006 ◽  
Vol 58 (4) ◽  
pp. 640-646 ◽  
Author(s):  
Iain D. Wilkinson ◽  
David A. Jellineck ◽  
David Levy ◽  
Frederik L. Giesel ◽  
Charles A. J. Romanowski ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Blood Volume ◽  
Transit Time ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Resonance Imaging ◽  
Regional Cerebral Blood ◽  
Regional Cerebral Blood Volume ◽  
First Moment

Abstract OBJECTIVE: Glucocorticoid analogues are often administered to patients with intracranial space-occupying lesions. Clinical response can be dramatic, but the neurophysiological response is not well documented. This study sought to investigate the blood-lesion barrier, blood-brain barrier, and cerebral perfusion characteristics of patients who have undergone such therapy using magnetic resonance imaging. METHODS: Seventeen patients with intracranial mass-enhancing lesions underwent magnetic resonance imaging before and after 3 days of high-dose dexamethasone therapy. Assessments of blood-lesion barrier and blood-brain barrier integrity were based on a dynamic T1-weighted exogenous contrast technique that yielded the normalized maximal change in contrast uptake (T1-uptake). Perfusion was assessed using a dynamic T2*-weighted exogenous contrast technique to yield relative regional cerebral blood volume and first-moment mean transit time. Comparisons were made in T1-uptake, regional cerebral blood volume, and first-moment mean transit time of both enhancing lesion and contralateral normal-appearing white matter (CNAWM) obtained before and after dexamethasone. RESULTS: Significant reduction in T1-uptake was observed (19% decrease, P &lt; 0.005) within enhancing pathological tissue, whereas no significant alteration was detected in CNAWM. Regional cerebral blood volume was significantly reduced in both enhancing tissue (28% decrease, P &lt; 0.005) and in CNAWM (20% decrease, P &lt; 0.001). Bolus first-moment mean transit time significantly increased (2.0 s prolongation, P &lt; 0.05) in CNAWM, whereas there was no significant change (1.4 s prolongation, P &gt; 0.05) within enhancing tissue. CONCLUSION: Glucocorticoid-analogue therapy not only affects the permeability of the blood-lesion barrier and lesion blood volume but also affects blood flow within normal-appearing contralateral parenchyma. There is a need for controls in steroid therapy in magnetic resonance imaging studies, which involve assessments of cerebrovascular function.

Abstract T P20: Correlation Between Whole Brain Ct Perfusion Maps And Non-contrast Ct Alberta Stroke Program Early Ct Score (aspects) In Patients Undergoing Acute Endovascular Stroke Interventions

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Simon Morr ◽  
Maxim Mokin ◽  
Ashish Sonig ◽  
Kenneth Snyder ◽  
Adnan Siddiqui ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Ct Perfusion ◽  
Pearson Correlation ◽  
Volume Data ◽  
Post Intervention ◽  
Whole Brain ◽  
Brain Ct ◽  
Time To Peak

Introduction: Tools for evaluating risk of post-intervention risk hemorrhage in the setting of acute stroke include a noncontrast head CT based Alberta Stroke Program Early CT score (ASPECTS) and contrasted CT based perfusion plots. The correlation between these parameters is unknown. Methods: We performed a retrospective analysis of a prospectively collected endovascular stroke database of patients with M1 middle cerebral artery occlusion who underwent endovascular recanalization. We reviewed admission preintervention noncontrast CT for Alberta Stroke Program Early CT score (ASPECTS) and 320-detector row whole brain CT perfusion parameters (Cerebral blood volume and time to peak). Pearson correlation was determined between cerebral blood volume on the side of the stroke and ASPECTS. Results: ASPECTS and CT perfusion map were identified in 45 and 43 patients respectively. Statistically significant correlation was found between ASPECTS and cerebral blood volume data on CT perfusion MAP. (p=0.034, r=-0.28). The correlation coefficient is very weak. No correlation could be found between time to peak and ASPECTS. Conclusion: A statistically significant, but weak correlation exists between ASPECTS and CBV. Further research is needed to assess the physiological meaning of diverse imaging modalities utilized in the acute stroke setting.

Abstract 2511: Reperfusion Measured by Mean Transit Time Predicts Clinical Improvement in Hyperacute Ischemic Stroke Patients Better Than Time-to-Peak and Tmax

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Andria L Ford ◽  
Hongyu An ◽  
Katie D Vo ◽  
William J Powers ◽  
Weili Lin ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Linear Regression ◽  
Acute Ischemic Stroke ◽  
Clinical Improvement ◽  
Independent Predictor ◽  
Mean Transit Time ◽  
Perfusion Deficit ◽  
Perfusion Parameter ◽  
Stroke Patients ◽  
Time To Peak

Background: Early reperfusion is associated with improved clinical outcome in acute ischemic stroke; however, there is no consensus regarding which perfusion parameter may best serve as a marker of clinical improvement. We compared three commonly used MRI perfusion parameters, mean transit time (MTT), time-to-peak (TTP), and Tmax, to identify which method of measuring reperfusion best predicted clinical improvement. Methods: Acute ischemic stroke patients underwent two MR scans: within 4.5 hours (tp1) and at 6 hours (tp2) after stroke onset. Co-registered MTT, TTP, and Tmax maps were generated to measure regions of perfusion deficit at tp1 and tp2. Perfusion deficit was defined as prolongation of MTT, TTP, or Tmax beyond four pre-specified thresholds for each parameter (4 thresholds were chosen to ensure results were not spuriously based on one threshold). Commonly-used thresholds (relative to contralateral median) were selected for each parameter: for MTT: >3, 4, 5, or 6 seconds (s), for TTP: >2, 4, 6, or 8s, and for Tmax: >2, 4, 6, and 8s. The volume of reperfusion (Vreperf) was defined as the volume of tissue with perfusion deficit at tp1 and no perfusion deficit at tp2. Clinical improvement was defined as: Admission NIH Stroke Scale (NIHSS) - 1 month NIHSS (ΔNIHSS). A multivariable linear regression model identified if Vreperf as measured by MTT, TTP, or Tmax was an independent predictor of clinical improvement after adjusting for patient age, admission NIHSS, tPA treatment, and volume of tp1 perfusion deficit. Results: Thirty-nine acute ischemic stroke patients were prospectively scanned at 2.8±.8hr (tp1) and 6.4±.4hr (tp2) after stroke onset (mean age=64, 44% female, 36% Black, mean NIHSS=14, 74% received IV tPA). Across the four thresholds, mean volume of perfusion deficit ranged from 58-96ml for MTT, 56-116ml for TTP, and 51-113ml for Tmax. Mean Vreperf ranged from 15-22ml for MTT, 15-23ml for TTP, and 14-21ml for Tmax. In the multivariable linear regression analysis, after adjusting for age, admission NIHSS, tPA treatment, and volume of tp1 perfusion deficit, Vreperf predicted ΔNIHSS for MTT=4s (p=0.007), MTT=5s (p=0.005), and MTT=6s (p=0.010), whereas Vreperf did not predict ΔNIHSS for any TTP or Tmax threshold ( Table ). Conclusion: Reperfusion, defined by MTT, was an independent predictor of clinical improvement, while reperfusion defined by TTP and Tmax were not. Therefore, MTT may be the best time-based perfusion parameter to define clinically-relevant reperfusion after stroke.

scholarly journals Predictive Value of the Velocity of Collateral Filling in Patients with Acute Ischemic Stroke

2014 ◽  
Vol 35 (2) ◽  
pp. 206-212 ◽  
Author(s):  
Sebastian E Beyer ◽  
Louisa von Baumgarten ◽  
Kolja M Thierfelder ◽  
Marietta Rottenkolber ◽  
Hendrik Janssen ◽  
...  
Keyword(s):  
Cerebral Blood Volume ◽  
Ct Perfusion ◽  
Mean Transit Time ◽  
Intravenous Thrombolysis ◽  
Lesion Size ◽  
Small Lesion ◽  
Time Resolved ◽  
Time To Peak ◽  
Magnetic Resonance Imaging Mri

The velocity of collateral filling can be assessed in dynamic time-resolved computed tomography (CT) angiographies and may predict initial CT perfusion (CTP) and follow-up lesion size. We included all patients with an M1± internal carotid artery (ICA) occlusion and follow-up imaging from an existing cohort of 1791 consecutive patients who underwent multimodal CT for suspected stroke. The velocity of collateral filling was quantified using the delay of time-to-peak (TTP) enhancement of the M2 segment distal to the occlusion. Cerebral blood volume (CBV) and mean transit time (MTT)-CBV mismatch were assessed in initial CTP. Follow-up lesion size was assessed by magnetic resonance imaging (MRI) or non-enhanced CT (NECT). Multivariate analyses were performed to adjust for extent of collateralization and type of treatment. Our study comprised 116 patients. Multivariate analysis showed a short collateral blood flow delay to be an independent predictor of a small CBV lesion ( P<0.001) and a large relative mismatch ( P<0.001) on initial CTP, of a small follow-up lesion ( P<0.001), and of a small difference between initial CBV and follow-up lesion size ( P=0.024). Other independent predictors of a small lesion on follow-up were a high morphologic collateral grade ( P=0.001), lack of an additional ICA occlusion ( P=0.009), and intravenous thrombolysis ( P=0.022). Fast filling of collaterals predicts initial CTP and follow-up lesion size and is independent of extent of collateralization.

scholarly journals Observer Agreement on Computed Tomography Perfusion Imaging in Acute Ischemic Stroke

Stroke ◽  
2019 ◽  
Vol 50 (11) ◽  
pp. 3108-3114 ◽  
Author(s):  
Salwa El-Tawil ◽  
Grant Mair ◽  
Xuya Huang ◽  
Eleni Sakka ◽  
Jeb Palmer ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Time Delay ◽  
Acute Stroke ◽  
Transit Time ◽  
Delay Time ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Observer Agreement ◽  
Intraobserver Agreement ◽  
Noncontrast Ct

Background and Purpose— Computed tomography (CT) perfusion (CTP) provides potentially valuable information to guide treatment decisions in acute stroke. Assessment of interobserver reliability of CTP has, however, been limited to small, mostly single center studies. We performed a large, internet-based study to assess observer reliability of CTP interpretation in acute stroke. Methods— We selected 24 cases from the IST-3 (Third International Stroke Trial), ATTEST (Alteplase Versus Tenecteplase for Thrombolysis After Ischaemic Stroke), and POSH (Post Stroke Hyperglycaemia) studies to illustrate various perfusion abnormalities. For each case, observers were presented with noncontrast CT, maps of cerebral blood volume, cerebral blood flow, mean transit time, delay time, and thresholded penumbra maps (dichotomized into penumbra and core), together with a short clinical vignette. Observers used a structured questionnaire to record presence of perfusion deficit, its extent compared with ischemic changes on noncontrast CT, and an Alberta Stroke Program Early CT Score for noncontrast CT and CTP. All images were viewed, and responses were collected online. We assessed observer agreement with Krippendorff-α. Intraobserver agreement was assessed by inviting observers who reviewed all scans for a repeat review of 6 scans. Results— Fifty seven observers contributed to the study, with 27 observers reviewing all 24 scans and 17 observers contributing repeat readings. Interobserver agreement was good to excellent for all CTP. Agreement was higher for perfusion maps compared with noncontrast CT and was higher for mean transit time, delay time, and penumbra map (Krippendorff-α =0.77, 0.79, and 0.81, respectively) compared with cerebral blood volume and cerebral blood flow (Krippendorff-α =0.69 and 0.62, respectively). Intraobserver agreement was fair to substantial in the majority of readers (Krippendorff-α ranged from 0.29 to 0.80). Conclusions— There are high levels of interobserver and intraobserver agreement for the interpretation of CTP in acute stroke, particularly of mean transit time, delay time, and penumbra maps.

The influence of decompressive craniectomy for major stroke on early cerebral perfusion

2015 ◽  
Vol 123 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Philipp Jörg Slotty ◽  
Marcel Alexander Kamp ◽  
Thomas Beez ◽  
Henrieke Beenen ◽  
Hans-Jakob Steiger ◽  
...  
Keyword(s):  
Decompressive Craniectomy ◽  
Cerebral Perfusion ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Residue Function ◽  
Perfusion Ct ◽  
Local Pressure ◽  
Partial Restoration ◽  
Time To Peak ◽  
Major Stroke

OBJECT Multiple trials have shown improved survival and functional outcome in patients treated with decompressive craniectomy (DC) for brain swelling following major stroke. It has been assumed that decompression induces an improvement in cerebral perfusion. This observational study directly measured cerebral perfusion before and after decompression. METHODS Sixteen patients were prospectively examined with perfusion CT within 6 hours prior to surgery and 12 hours after surgery. Preoperative and postoperative perfusion measurements were compared and correlated. RESULTS Following DC there was a significant increase in cerebral blood flow in all measured territories and additionally an increase in cerebral blood volume in the penumbra (p = 0.03). These changes spread as far as the contralateral hemisphere. No significant changes in mean transit time or Tmax (time-to-peak residue function) were observed. CONCLUSIONS The presurgical perfusion abnormalities likely reflected local pressure-induced hypoperfusion with impaired autoregulation. The improvement in perfusion after decompression implied an increase in perfusion pressure, likely linked to partial restoration of autoregulation. The increase in perfusion that was observed might partially be responsible for improved clinical outcome following decompressive surgery for major stroke. The predictive value of perfusion CT on outcome needs to be evaluated in larger trials.

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