scholarly journals Neural Network-derived perfusion maps: a Model-free approach to computed tomography perfusion in patients with acute ischemic stroke

2021 ◽  
Author(s):  
Umberto A. Gava ◽  
Federico D’Agata ◽  
Enzo Tartaglione ◽  
Marco Grangetto ◽  
Francesca Bertolino ◽  
...  
Keyword(s):  
Neural Network ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
State Of The Art ◽  
Ct Perfusion ◽  
Pearson Correlation ◽  
Ground Truth ◽  
Infarct Core ◽  
Model Free ◽  
Perfusion Maps

AbstractPurposeIn this study we investigate whether a Convolutional Neural Network (CNN) can generate clinically relevant parametric maps from CT perfusion data in a clinical setting of patients with acute ischemic stroke.MethodsTraining of the CNN was done on a subset of 100 perfusion data, while 15 samples were used as validation. All the data used for the training/validation of the network and to generate ground truth (GT) maps, using a state-of-the-art deconvolution-algorithm, were previously pre-processed using a standard pipeline. Validation was carried out through manual segmentation of infarct core and penumbra on both CNN-derived maps and GT maps. Concordance among segmented lesions was assessed using the Dice and the Pearson correlation coefficients across lesion volumes.ResultsMean Dice scores from two different raters and the GT maps were > 0.70 (good-matching). Inter-rater concordance was also high and strong correlation was found between lesion volumes of CNN maps and GT maps (0.99, 0.98).ConclusionOur CNN-based approach generated clinically relevant perfusion maps that are comparable to state-of-the-art perfusion analysis methods based on deconvolution of the data. Moreover, the proposed technique requires less information to estimate the ischemic core and thus might allow the development of novel perfusion protocols with lower radiation dose.

Higher agreement in endovascular treatment decision-making than in parametric quantifications among automated CT perfusion software packages in acute ischemic stroke

2021 ◽  
pp. 1-12
Author(s):  
Manuel Pérez-Pelegrí ◽  
Carles Biarnés ◽  
Santiago Thió-Henestrosa ◽  
Sebastià Remollo ◽  
Alfredo Gimeno ◽  
...  
Keyword(s):  
Decision Making ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Ct Perfusion ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Treatment Decision ◽  
Observer Agreement ◽  
Infarct Core ◽  
Software Packages

BACKGROUND AND OBJECTIVE: Estimates of parameters used to select patients for endovascular thrombectomy (EVT) for acute ischemic stroke differ among software packages for automated computed tomography (CT) perfusion analysis. To determine impact of these differences in decision making, we analyzed intra-observer and inter-observer agreement in recommendations about whether to perform EVT based on perfusion maps from 4 packages. METHODS: Perfusion CT datasets from 63 consecutive patients with suspected acute ischemic stroke were retrospectively postprocessed with 4 packages of Minerva, RAPID, Olea, and IntelliSpace Portal (ISP). We used Pearson correlation coefficients and Bland-Altman analysis to compare volumes of infarct core, penumbra, and mismatch calculated by Minerva and RAPID. We used kappa analysis to assess agreement among decisions of 3 radiologists about whether to recommend EVT based on maps generated by 4 packages. RESULTS: We found significant differences between using Minerva and RAPID to estimate penumbra (67.39±41.37mL vs. 78.35±45.38 mL, p <  0.001) and mismatch (48.41±32.03 vs. 61.27±32.73mL, p <  0.001), but not of infarct core (p = 0.230). Pearson correlation coefficients were 0.94 (95%CI:0.90–0.96) for infarct core, 0.87 (95%CI:0.79–0.91) for penumbra, and 0.72 (95%CI:0.57–0.83) for mismatch volumes (p <  0.001). Limits of agreements were (–21.22–25.02) for infarct core volumes, (–54.79–32.88) for penumbra volumes, and (–60.16–34.45) for mismatch volumes. Final agreement for EVT decision-making was substantial between Minerva vs. RAPID (k = 0.722), Minerva vs. Olea (k = 0.761), and RAPID vs. Olea (k = 0.782), but moderate for ISP vs. the other three. CONCLUSIONS: Despite quantitative differences in estimates of infarct core, penumbra, and mismatch using 4 software packages, their impact on radiologists’ decisions about EVT is relatively small.

Predictive value of time-variant color-coded multiphase CT angiography (mCTA) regarding clinical outcome of acute ischemic stroke: in comparison with conventional mCTA and CT perfusion

2020 ◽  
pp. 028418512098177
Author(s):  
Yu Lin ◽  
Nannan Kang ◽  
Jianghe Kang ◽  
Shaomao Lv ◽  
Jinan Wang
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Predictive Value ◽  
Ct Perfusion ◽  
Roc Curves ◽  
Multivariate Logistic Regression Model ◽  
Infarct Core ◽  
Predictive Values ◽  
Significant Difference ◽  
Core Volume

Background Color-coded multiphase computed tomography angiography (mCTA) can provide time-variant blood flow information of collateral circulation for acute ischemic stroke (AIS). Purpose To compare the predictive values of color-coded mCTA, conventional mCTA, and CT perfusion (CTP) for the clinical outcomes of patients with AIS. Material and Methods Consecutive patients with anterior circulation AIS were retrospectively reviewed at our center. Baseline collateral scores of color-coded mCTA and conventional mCTA were assessed by a 6-point scale. The reliabilities between junior and senior observers were assessed by weighted Kappa coefficients. Receiver operating characteristic (ROC) curves and multivariate logistic regression model were applied to evaluate the predictive capabilities of color-coded mCTA and conventional mCTA scores, and CTP parameters (hypoperfusion and infarct core volume) for a favorable outcome of AIS. Results A total of 138 patients (including 70 cases of good outcomes) were included in our study. Patients with favorable prognoses were correlated with better collateral circulations on both color-coded and conventional mCTA, and smaller hypoperfusion and infarct core volume (all P < 0.05) on CTP. ROC curves revealed no significant difference between the predictive capability of color-coded and conventional mCTA ( P = 0.427). The predictive value of CTP parameters tended to be inferior to that of color-coded mCTA score (all P < 0.001). Both junior and senior observers had consistently excellent performances (κ = 0.89) when analyzing color-coded mCTA maps. Conclusion Color-coded mCTA provides prognostic information of patients with AIS equivalent to or better than that of conventional mCTA and CTP. Junior radiologists can reach high diagnostic accuracy when interpreting color-coded mCTA images.

Abstract 3200: Comparison of CT Perfusion Mismatch with Perfusion-Diffusion MRI in Ischemic Stroke - a Reliable Alternative?

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Bruce C Campbell ◽  
Søren Christensen ◽  
Christopher R Levi ◽  
Patricia M Desmond ◽  
Geoffrey A Donnan ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Diffusion Mri ◽  
Roc Analysis ◽  
Ct Perfusion ◽  
Residue Function ◽  
Infarct Core ◽  
Widespread Application ◽  
Time To Peak ◽  
Value Decomposition

Background and purpose: CT-perfusion (CTP) is widely and rapidly accessible for imaging acute ischemic stroke. However, there has been limited validation of CTP parameters against the more intensively studied MRI perfusion-diffusion mismatch paradigm. We tested the correspondence of CTP with contemporaneous perfusion-diffusion MRI. Methods: Acute ischemic stroke patients <6hr after onset had CTP and perfusion-diffusion MRI within 1hr, before reperfusion therapies. Relative cerebral blood flow (relCBF) and time-to-peak of the deconvolved tissue-residue-function (Tmax) were calculated (standard singular value decomposition deconvolution). The diffusion lesion was registered to the CTP slabs and manually outlined to its maximal visual extent. CT-infarct core was defined as relCBF<31% contralateral mean as previously published using this software. The volumetric accuracy of relCBF core compared to the diffusion lesion was tested in isolation, but also when restricted to pixels with relative time-to-peak (TTP) >4sec, to reduce artifactual false positive low CBF (eg in leukoaraiosis). The MR Tmax>6sec perfusion lesion (previously validated to define penumbral tissue at risk of infarction) was automatically segmented and registered to the CTP slabs. Receiver operating characteristic (ROC) analysis determined the optimal CT-Tmax threshold to match MR-Tmax>6sec, confidence intervals generated by bootstrapping. Agreement of these CT parameters with MR perfusion-diffusion mismatch on co-registered slabs was assessed (mismatch ratio >1.2, absolute mismatch>10mL, infarct core<70mL). Results: In analysis of 98 CTP slabs (54 patients, median onset to CT 190min, median CT to MR 30min), volumetric agreement with the diffusion lesion was substantially improved by constraining relCBF<31% within the automated TTP perfusion lesion ROI (median magnitude of volume difference 9.0mL vs unconstrained 13.9mL, p<0.001). ROC analysis demonstrated the best CT-Tmax threshold to match MR-Tmax>6sec was 6.2sec (95% confidence interval 5.6-7.3sec, ie not significantly different to 6sec), sensitivity 91%, specificity 70%, AUC 0.87. Using CT-Tmax>6s “penumbra” and relCBF<31% (restricted to TTP>4s) “core”, volumetric agreement was sufficient for 90% concordance between CT and MRI-based mismatch status (kappa 0.80). Conclusions: Automated CTP mismatch classification using relCBF and Tmax is similar to perfusion-diffusion MRI. CTP may allow more widespread application of the “mismatch” paradigm in clinical practice and trials.

What is the impact of head movement on automated CT perfusion mismatch evaluation in acute ischemic stroke?

2021 ◽  
pp. neurintsurg-2021-017510
Author(s):  
Arne Potreck ◽  
Fatih Seker ◽  
Matthias Anthony Mutke ◽  
Charlotte Sabine Weyland ◽  
Christian Herweh ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Head Movement ◽  
Ct Perfusion ◽  
Treatment Decision ◽  
Brain Perfusion ◽  
Left Middle Cerebral Artery ◽  
Ct Scanner ◽  
Infarct Core ◽  
The Impact

ObjectivesAutomated CT perfusion mismatch assessment is an established treatment decision tool in acute ischemic stroke. However, the reliability of this method in patients with head motion is unclear. We therefore sought to evaluate the influence of head movement on automated CT perfusion mismatch evaluation.MethodsUsing a realistic CT brain-perfusion-phantom, 7 perfusion mismatch scenarios were simulated within the left middle cerebral artery territory. Real CT noise and artificial head movement were added. Thereafter, ischemic core, penumbra volumes and mismatch ratios were evaluated using an automated mismatch analysis software (RAPID, iSchemaView) and compared with ground truth simulated values.ResultsWhile CT scanner noise alone had only a minor impact on mismatch evaluation, a tendency towards smaller infarct core estimates (mean difference of −5.3 (−14 to 3.5) mL for subtle head movement and −7.0 (−14.7 to 0.7) mL for strong head movement), larger penumbral estimates (+9.9 (−25 to 44) mL and +35 (−14 to 85) mL, respectively) and consequently larger mismatch ratios (+0.8 (−1.5 to 3.0) for subtle head movement and +1.9 (−1.3 to 5.1) for strong head movement) were noted in dependence of patient head movement.ConclusionsMotion during CT perfusion acquisition influences automated mismatch evaluation. Potentially treatment-relevant changes in mismatch classifications in dependence of head movement were observed and occurred in favor of mechanical thrombectomy.

Topographic correlation of infarct area on CT perfusion with functional outcome in acute ischemic stroke

2020 ◽  
Vol 132 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Neil Haranhalli ◽  
Nnenna Mbabuike ◽  
Sanjeet S. Grewal ◽  
Tasneem F. Hasan ◽  
Michael G. Heckman ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Functional Outcome ◽  
Ct Perfusion ◽  
Multivariable Analysis ◽  
Reperfusion Therapy ◽  
Infarct Core ◽  
Anterior Circulation ◽  
Logistic Regression Models ◽  
Confounding Variables

OBJECTIVEThe role of CT perfusion (CTP) in the management of patients with acute ischemic stroke (AIS) remains a matter of debate. The primary aim of this study was to evaluate the correlation between the areas of infarction and penumbra on CTP scans and functional outcome in patients with AIS.METHODSThis was a retrospective review of 100 consecutively treated patients with acute anterior circulation ischemic stroke who underwent CT angiography (CTA) and CTP at admission between February 2011 and October 2014. On CTP, the volume of ischemic core and penumbra was measured using the Alberta Stroke Program Early CT Score (ASPECTS). CTA findings were also noted, including the site of occlusion and regional leptomeningeal collateral (rLMC) score. Functional outcome was defined by modified Rankin Scale (mRS) score obtained at discharge. Associations of CTP and CTA parameters with mRS scores at discharge were assessed using multivariable proportional odds logistic regression models.RESULTSThe median age was 67 years (range 19–95 years), and the median NIH Stroke Scale score was 16 (range 2–35). In a multivariable analysis adjusting for potential confounding variables, having an infarct on CTP scans in the following regions was associated with a worse mRS score at discharge: insula ribbon (p = 0.043), perisylvian fissure (p < 0.001), motor strip (p = 0.007), M2 (p < 0.001), and M5 (p = 0.023). A worse mRS score at discharge was more common in patients with a greater volume of infarct core (p = 0.024) and less common in patients with a greater rLMC score (p = 0.004).CONCLUSIONSThe results of this study provide evidence that several CTP parameters are independent predictors of functional outcome in patients with AIS and have potential to identify those patients most likely to benefit from reperfusion therapy in the treatment of AIS.

scholarly journals A Convolutional Neural Network for Anterior Intra-Arterial Thrombus Detection and Segmentation on Non-Contrast Computed Tomography of Patients with Acute Ischemic Stroke

2020 ◽  
Vol 10 (14) ◽  
pp. 4861
Author(s):  
Manon L. Tolhuisen ◽  
Elena Ponomareva ◽  
Anne M. M. Boers ◽  
Ivo G. H. Jansen ◽  
Miou S. Koopman ◽  
...  
Keyword(s):  
Neural Network ◽  
Computed Tomography ◽  
Ischemic Stroke ◽  
Convolutional Neural Network ◽  
Acute Ischemic Stroke ◽  
Ground Truth ◽  
Correct Identification ◽  
Anterior Circulation ◽  
Vessel Occlusion ◽  
Comprehensive Stroke Center

The aim of this study was to develop a convolutional neural network (CNN) that automatically detects and segments intra-arterial thrombi on baseline non-contrast computed tomography (NCCT) scans. We retrospectively collected computed tomography (CT)-scans of patients with an anterior circulation large vessel occlusion (LVO) from the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands trial, both for training (n = 86) and validation (n = 43). For testing we included patients with (n = 58) and without (n = 45) an LVO from our comprehensive stroke center. Ground truth was established by consensus between two experts using both CT angiography and NCCT. We evaluated the CNN for correct identification of a thrombus, its location and thrombus segmentation and compared these with the results of a neurologist in training and expert neuroradiologist. Sensitivity of the CNN thrombus detection was 0.86, vs. 0.95 and 0.79 for the neuroradiologists. Specificity was 0.65 for the network vs. 0.58 and 0.82 for the neuroradiologists. The CNN correctly identified the location of the thrombus in 79% of the cases, compared to 81% and 77% for the neuroradiologists. The sensitivity and specificity for thrombus identification and the rate for correct thrombus location assessment by the CNN were similar to those of expert neuroradiologists.

Abstract 3048: Real-World Clinical Use of CT Perfusion for Diagnosis and Prediction of Lesion Growth in Acute Ischemic Stroke

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Branko N Huisa ◽  
William P Neil ◽  
Nhu T Bruce ◽  
Marcel Maya ◽  
Benedict Pereira ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Real World ◽  
Cerebral Blood Volume ◽  
Ct Perfusion ◽  
Medical Center ◽  
Brain Mri ◽  
Academic Medical Center ◽  
Acute Ischemia ◽  
Perfusion Maps

Background: Diffusion-weighted imaging (DWI) detects acute ischemia with a high sensitivity. In research centers, qualitative CT perfusion (CTP) mapping correlates well with DWI and may accurately differentiate the infarct core from ischemic penumbra. The value of the CTP in real-world clinical practice, however, has not been fully established. We investigated the yield of CTP - derived cerebral blood volume (CBV) and mean transient time (MTT) for the detection of cerebral ischemia in a sample of acute ischemic stroke (AIS) patients. Methods: In a large metropolitan academic medical center that is a certified Primary Stroke Center (PSC) we retrospectively studied 162 patients who presented between January 2008 and July 2010 with symptoms suggestive of AIS. All patients had an initial Code Brain protocol including non-contrast head CT, CTP, and CTA. As clinically indicated, some patients underwent follow up brain MRI within 48 hours. Acute perfusion maps were derived in real time by a trained operator. From the obtained images CBV, MTT and DWI lesion volumes were manually traced using planimetry (ImageJ v1.42) by two stroke neurologists blinded to clinical information. Volumes were calculated using the Cavaleri theorem. Sensitivity, specificity and statistical analysis were calculated using Graph Pad 5.0. Results: Of 162 patients with acute stroke-like symptoms, 73 had DWI lesions. The sensitivity and specificity to detect abnormal DWI signals were 23% and 100%, for CBV; and 43.8% and 98.9% for MTT. For DWI lesions ≥5ml the yield was 59.3% for CVB and 77.8% for MTT. For lesions ≥10ml the yield was 68.4% for CBV and 89.5% for MTT. In patients with NIHSS ≥5, CBV predicted abnormal DWI in 22.6% and MTT in 35.5%. In patients with NIHSS ≥10, CBV and MTT, both had a yield of 50.0%. A CBV - MTT mismatch of >25% predicted MRI lesion extension in 81.25% of the cases. There were small but significant correlations for DWI versus CBV lesion volumes ( r 2 0.32, P= 0.0001), and for DWI versus MTT lesion volumes ( r 2 0.29, P <0.0001). Correlation between DWI and perfusion maps for MCA territory infarcts were CBV ( r 2 0.3, P <0.0001) and MTT ( r 2 0.45, P <0.0001). Conclusions: In real-world deployment during a Code Brain protocol in a busy PSC, acute imaging with CTP did not predict DWI lesions on brain MRI with sufficient accuracy. In patients with large lesions the predictive value was better.

scholarly journals Infarct-core CT perfusion parameters in predicting post-thrombolysis hemorrhagic transformation of acute ischemic stroke

2018 ◽  
Vol 53 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Crt Langel ◽  
Katarina Surlan Popovic
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Receiver Operating Characteristic ◽  
Operating Characteristic ◽  
Receiver Operating Characteristic Analysis ◽  
Ct Perfusion ◽  
Hemorrhagic Transformation ◽  
Characteristic Analysis ◽  
Infarct Core ◽  
Receiver Operating

Abstract Background Intravenous thrombolysis (IVT) is the method of choice in reperfusion treatment of patients with signs and symptoms of acute ischemic stroke (AIS) lasting less than 4.5 hours. Hemorrhagic transformation (HT) of acute ischemic stroke is a serious complication of IVT and occurs in 4.5–68.0% of clinical cases. The aim of our study was to determine the infarct core CT perfusion parameter (CTPP) most predictive of HT. Patients and methods Seventy-five patients with AIS who had undergone CT perfusion (CTP) imaging and were treated with IVT were enrolled in this retrospective study. Patients with and without HT after IVT were defined as cases and controls, respectively. Controls were found by matching for time from AIS symptom onset to IVT ± 0.5 h. The following CTPPs were measured: cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), relative CBF (rCBF) and relative CBV (rCBV). Receiver operating characteristic analysis curves of significant CTPPs determined cut-off values that best predict HT. Results There was a significant difference between cases and controls for CBF (p = 0.004), CBV (p = 0.009), rCBF (p < 0.001) and rCBV (p = 0.001). Receiver operating characteristic analysis revealed that rCBF < 4.5% of the contralateral mean (area under the curve = 0.736) allowed prediction of HT with a sensitivity of 71.0% and specificity of 52.5%. Conclusions CTP imaging has a considerable role in HT prediction, assisting in selection of patients that are likely to benefit from IVT. rCBF proved to have the highest HT predictive value.

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