Incorporation of relative cerebral blood flow into CT perfusion maps reduces false ’at risk' penumbra

2017 ◽  
Vol 10 (7) ◽  
pp. 657-662 ◽  
Author(s):  
Shlomi Peretz ◽  
David Orion ◽  
David Last ◽  
Yael Mardor ◽  
Yotam Kimmel ◽  
...  
Keyword(s):  
At Risk ◽  
Acute Stroke ◽  
Ct Perfusion ◽  
False Negative ◽  
Stroke Patients ◽  
True Negative ◽  
True Negative Rate ◽  
Negative Rate ◽  
Perfusion Maps

PurposeThe region defined as ‘at risk’ penumbra by current CT perfusion (CTP) maps is largely overestimated. We aimed to quantitate the portion of true ‘at risk’ tissue within CTP penumbra and to determine the parameter and threshold that would optimally distinguish it from false ‘at risk’ tissue, that is, benign oligaemia.MethodsAmong acute stroke patients evaluated by multimodal CT (NCCT/CTA/CTP) we identified those that had not undergone endovascular/thrombolytic treatment and had follow-up NCCT. Maps of absolute and relative CBF, CBV, MTT, TTP and Tmax as well as summary maps depicting infarcted and penumbral regions were generated using the Intellispace Portal (Philips Healthcare, Best, Netherlands). Follow-up CT was automatically co-registered to the CTP scan and the final infarct region was manually outlined. Perfusion parameters were systematically analysed – the parameter that resulted in the highest true-negative-rate (ie, proportion of benign oligaemia correctly identified) at a fixed, clinically relevant false-negative-rate (ie, proportion of ‘missed’ infarct) of 15%, was chosen as optimal. It was then re-applied to the CTP data to produce corrected perfusion maps.ResultsForty seven acute stroke patients met selection criteria. Average portion of infarcted tissue within CTP penumbra was 15%±2.2%. Relative CBF at a threshold of 0.65 yielded the highest average true-negative-rate (48%), enabling reduction of the false ‘at risk’ penumbral region by ~half.ConclusionsApplying a relative CBF threshold on relative MTT-based CTP maps can significantly reduce false ‘at risk’ penumbra. This step may help to avoid unnecessary endovascular interventions.

scholarly journals The Effect of a Diverse Dataset for Transfer Learning in Thermal Person Detection

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1982 ◽  
Author(s):  
Noor Ul Huda ◽  
Bolette D. Hansen ◽  
Rikke Gade ◽  
Thomas B. Moeslund
Keyword(s):  
Transfer Learning ◽  
Privacy Preservation ◽  
False Negative ◽  
False Negative Rate ◽  
Model Adaptation ◽  
True Negative ◽  
True Negative Rate ◽  
Negative Rate ◽  
Thermal Cameras ◽  
The Impact

Thermal cameras are popular in detection for their precision in surveillance in the dark and for privacy preservation. In the era of data driven problem solving approaches, manually finding and annotating a large amount of data is inefficient in terms of cost and effort. With the introduction of transfer learning, rather than having large datasets, a dataset covering all characteristics and aspects of the target place is more important. In this work, we studied a large thermal dataset recorded for 20 weeks and identified nine phenomena in it. Moreover, we investigated the impact of each phenomenon for model adaptation in transfer learning. Each phenomenon was investigated separately and in combination. the performance was analyzed by computing the F1 score, precision, recall, true negative rate, and false negative rate. Furthermore, to underline our investigation, the trained model with our dataset was further tested on publicly available datasets, and encouraging results were obtained. Finally, our dataset was also made publicly available.

Differences in CT Perfusion Maps Generated by Different Commercial Software: Quantitative Analysis by Using Identical Source Data of Acute Stroke Patients

Radiology ◽  
2010 ◽  
Vol 254 (1) ◽  
pp. 200-209 ◽  
Author(s):  
Kohsuke Kudo ◽  
Makoto Sasaki ◽  
Kei Yamada ◽  
Suketaka Momoshima ◽  
Hidetsuna Utsunomiya ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Acute Stroke ◽  
Ct Perfusion ◽  
Stroke Patients ◽  
Commercial Software ◽  
Source Data ◽  
Perfusion Maps

scholarly journals Treatment with Diazepam in Acute Stroke Prevents Poststroke Seizures: A Substudy of the EGASIS Trial

2021 ◽  
pp. 1-6
Author(s):  
Julia H. van Tuijl ◽  
Elisabeth P.M. van Raak ◽  
Robert J. van Oostenbrugge ◽  
Albert P. Aldenkamp ◽  
Rob P.W. Rouhl
Keyword(s):  
Placebo Group ◽  
Acute Stroke ◽  
Incidence Rate Ratio ◽  
Day Treatment ◽  
Stroke Patients ◽  
Early Administration ◽  
Anterior Circulation ◽  
Double Blind

<b><i>Objective:</i></b> The frequency of seizures after stroke is high, with a severe impact on the quality of life. However, little is known about their prevention. Therefore, we investigated whether early administration of diazepam prevents the development of seizures in acute stroke patients. <b><i>Methods:</i></b> We performed a substudy of the EGASIS trial, a multicenter double-blind, randomized trial in which acute stroke patients were treated with diazepam or placebo for 3 days. Follow-up was after 2 weeks and 3 months. The occurrence of seizures was registered prospectively as one of the prespecified secondary outcomes. <b><i>Results:</i></b> 784 EGASIS patients were eligible for this substudy (389 treated with diazepam [49.6%] and 395 treated with placebo [50.4%]). Seizures were reported in 19 patients (2.4% of the total patient group). Seizures occurred less frequently in patients treated with diazepam (1.5 vs. 3.3% in the placebo group); however, this difference was only statistically significant in patients with a cortical anterior circulation infarction (0.9% in the diazepam group vs. 4.6% in the placebo group, incidence rate ratio 0.20, 95% CI: 0.05–0.78, <i>p</i> = 0.02, NNT = 27). <b><i>Conclusion:</i></b> We found that a 3-day treatment with diazepam after acute cortical anterior circulation stroke prevents the occurrence of seizures in the first 3 months following stroke.

scholarly journals The South African dysphagia screening tool (SADS): A screening tool for a developing context

2016 ◽  
Vol 63 (1) ◽  
Author(s):  
Calli Ostrofsky ◽  
Jaishika Seedat
Keyword(s):  
At Risk ◽  
Acute Stroke ◽  
South African ◽  
Screening Tool ◽  
Diagnostic Assessment ◽  
The South ◽  
Stroke Patients ◽  
Cohen’S Kappa ◽  
Cohen's Kappa ◽  
Government Hospitals

Background: Notwithstanding its value, there are challenges and limitations to implementing a dysphagia screening tool from a developed contexts in a developing context. The need for a reliable and valid screening tool for dysphagia that considers context, systemic rules and resources was identified to prevent further medical compromise, optimise dysphagia prognosis and ultimately hasten patients’ return to home or work.Methodology: To establish the validity and reliability of the South African dysphagia screening tool (SADS) for acute stroke patients accessing government hospital services. The study was a quantitative, non-experimental, correlational cross-sectional design with a retrospective component. Convenient sampling was used to recruit 18 speech-language therapists and 63 acute stroke patients from three South African government hospitals. The SADS consists of 20 test items and was administered by speech-language therapists. Screening was followed by a diagnostic dysphagia assessment. The administrator of the tool was not involved in completing the diagnostic assessment, to eliminate bias and prevent contamination of results from screener to diagnostic assessment. Sensitivity, validity and efficacy of the screening tool were evaluated against the results of the diagnostic dysphagia assessment. Cohen’s kappa measures determined inter-rater agreement between the results of the SADS and the diagnostic assessment.Results and conclusion: The SADS was proven to be valid and reliable. Cohen’s kappa indicated a high inter-rater reliability and showed high sensitivity and adequate specificity in detecting dysphagia amongst acute stroke patients who were at risk for dysphagia. The SADS was characterised by concurrent, content and face validity. As a first step in establishing contextual appropriateness, the SADS is a valid and reliable screening tool that is sensitive in identifying stroke patients at risk for dysphagia within government hospitals in South Africa.

Abstract 1122‐000034: Systematic CT‐Perfusion acquisition in All Suspected Stroke Patients Increases Vascular Occlusion Detection and Thrombectomy Rates

2021 ◽  
Vol 1 (S1) ◽  
Author(s):  
Marta Olive‐Gadea ◽  
Manuel Requena ◽  
Facundo Diaz ◽  
Alvaro Garcia‐Tornel ◽  
Marta Rubiera ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Clinical Symptoms ◽  
Ct Perfusion ◽  
False Negative ◽  
False Negative Rate ◽  
Vascular Occlusion ◽  
Stroke Patients ◽  
Imaging Protocols ◽  
The Impact

Introduction : In acute ischemic stroke patients, current guidelines recommend noninvasive vascular imaging to identify intracranial vessel occlusions (VO) that may benefit from endovascular treatment (EVT). However, VO can be missed in CT angiography (CTA) readings. We aim to evaluate the impact of consistently including CT perfusion (CTP) in admission stroke imaging protocols on VO diagnosis and EVT rates. Methods : We included patients with a suspected acute ischemic stroke that underwent urgent non‐contrast CT, CTA and CTP from April to October 2020. Hypoperfusion areas defined by Tmax>6s delay (RAPID software), congruent with the clinical symptoms and a vascular territory, were considered due to a VO (CTP‐VO). Cases in which mechanical thrombectomy was performed were defined as therapeutically relevant VO (EVT‐VO). For patients that received EVT, site of VO according to digital subtraction angiography was recorded. Two experienced neuroradiologists blinded to CTP but not to clinical symptoms, retrospectively evaluated NCCT and CTA to identify intracranial VO (CTA‐VO). We analyzed CTA‐VO sensitivity and specificity at detecting CTP‐VO and EVT‐VO respecitvely. We performed a logistic regression to test the association of Tmax>6s volumes with CTA‐VO identification and indication of EVT. Results : Of the 338 patients included in the analysis, 157 (46.5%) presented a CTP‐VO, (median Tmax>6s: 73 [29‐127] ml). CTA‐VO was identified in 83 (24.5%) of the cases. Overall CTA‐VO sensitivity for the detection of CTP‐VO was 50.3% and specificity was 97.8%. Higher hypoperfusion volume was associated with an increased CTA‐VO detection, with an odds ratio of 1.03 (95% confidence interval 1.02‐1.04) (figure). DSA was indicated in 107 patients; in 4 of them no EVT was attempted due to recanalization or a too distal VO in the first angiographic run. EVT was performed in 103 patients (30.5%. Tmax>6s: 102 [63‐160] ml), representing 65.6% of all CTP‐VO. Overall CTA‐VO sensitivity for the detection of EVT‐VO was 69.9%. The CTA‐VO sensitivity for detecting patients with indication of EVT according to clinical guidelines was as follows: 91.7% for ICA occlusions and 84.4% for M1‐MCA occlusions. For all other occlusion sites that received EVT, the CTA‐VO sensitivity was 36.1%. The overall specificity was 95.3%. Among patients who received EVT, CTA‐VO was not detected in 31 cases, resulting in a false negative rate of 30.1%. False negative CTA‐VO cases had lower Tmax>6s volumes (69[46‐99.5] vs 126[84‐169.5]ml, p<0.001) and lower NIHSS (13[8.5‐16] vs 17[14‐21], p<0.001). Conclusions : Systematically including CTP perfusion in the acute stroke admission imaging protocols may increase the diagnosis of VO and rate of EVT.

True Negative Rate

2011 ◽  
pp. 999-999
Author(s):  
William Uther ◽  
Dunja Mladenić ◽  
Massimiliano Ciaramita ◽  
Bettina Berendt ◽  
Aleksander Kołcz ◽  
...  
Keyword(s):  
True Negative ◽  
True Negative Rate ◽  
Negative Rate

scholarly journals Effectiveness Of Transient Evoked Otoacoustic Emission (TEOAE) Test For Neonatal Auditory Screening

2018 ◽  
Vol 08 (02) ◽  
pp. 77-81
Author(s):  
Shanila Feroz ◽  
Iqbal Hussain Udaipurwala ◽  
Danish Muhammad Khan ◽  
Fatima Iqbal Hussain
Keyword(s):  
Hearing Loss ◽  
Predictive Value ◽  
False Negative ◽  
Otoacoustic Emission ◽  
Normal Hearing ◽  
Speech Development ◽  
True Negative ◽  
Cross Sectional ◽  
Transient Evoked Otoacoustic Emission

Objective: The purpose of this study is to assess the efficacy of Transient Evoked Otoacoustic Emission (TEOAE) as screening test for auditory function in neonates. Study Design: A cross-sectional study Place and Duration of Study: This study was conducted at United Medical and Dental College, Creek General Hospital, Karachi, from July 2106 to May 2017. A total number of 120 newborn babies were screened for hearing loss before discharge from hospital but 20 were lost for follow up and 100 cases were included in this study. Method: TEOAE was done in all neonates born during this period at 3rd day after birth. Those who were found to have hearing loss, TEOAE was repeated at the end of 1st week and again in 6th week after birth. BERA was done in those cases who showed hearing loss on TEOAE on all three occasions. All the 100 cases were followed up regularly for more than one year for appearance of any sign or symptom related with hearing loss or speech development failure. Result: Out of 100 cases included in this study, 96 were found to have no hearing loss on TEOAE and 1 on BERA test. Remaining three cases were found to have hearing loss on both TEOAE and BERA test. True negative cases where no hearing loss was found on TEOAE and subsequent follow up were 96. True positive cases were 3 where hearing loss was found on TEOAE and BERA and also on subsequent follow-up. False positive case was 1, where hearing loss was detected on TEOAE but BERA showed normal hearing and subsequent follow-up also showed normal hearing and false negative result was not detected in any case. Sensitivity of TEOAE was found to be 100%, specificity is 98.9%, accuracy is 99%, positive predictive value is 75% and negative predictive value is 100% in this study. Conclusion: TEOAE was found to be a cost-effective and practicable method of recognizing congenital hearing loss. It should be done in all newborns as routine screening for hearing loss

Abstract TMP1: Predicting Scale Design and Derivation to Select Acute Ischemic Stroke Patients for Direct Angiosuite Intervention

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Zeguang Ren ◽  
Runqi Wangqin ◽  
Maxim Mokin ◽  
Anxin Wang ◽  
Liang Zhao ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Stroke ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Vascular Imaging ◽  
Operating Characteristics ◽  
Stroke Patients ◽  
Additional Time ◽  
Vessel Occlusion

Introduction: Vascular imaging after head CT to confirm large vessel occlusion (LVO) for acute stroke patients requires additional time and delays recanalization. We developed the T hrombectomy A cute M echanical re P erfusion A ssessment ( TAMPA ) scale for selecting patients with LVO for direct angiosuite transfer and intervention to improve recanalization time. Methods: The TAMPA scale was developed from our prospectively collected “Get with the Guidelines” database. We included all “stroke alert” patients between 1/2017 and 8/2018 with vascular imaging and National Institutes of Health Stroke Scale scores between 5 and 25. We excluded patients with immediately obvious non-stroke diagnoses, those lacking subsequent vascular imaging, or those with incomplete records. Different variables were collected. The TAMPA scale receiver operating characteristics curve (ROC) was compared with the ROCs of other commonly used scales. Results: 571 eligible patients from 2115 “acute stroke alerts” were identified for developing the TAMPA scale. The scale was established with a combination of 5 items with a total score of 9: CT hyperdense sign, parenchymal hypodensity, lateralizing hemiparalysis, gaze deviation and speech disturbance. A cutoff of ≥ 4 yielded a sensitivity of 68.98%, specificity of 72.91%, false positive rate of 27.09%, and false negative rate of 31.02%. Compared with other scales, such as total NIHSS, C-stat/CPSSS, RACE, FAST-ED and 3I-SS, the TAMPA scale had the best ROC for the selected group of patients. Conclusions: The TAMPA scale accurately predicts presence of clinically amenable LVO in patients with moderate to severe ischemic stroke. Use of the TAMPA scale to identify high probability mechanical embolectomy candidates for direct transfer to the angiosuite could potentially reduce revascularization times and increase treatment rates.

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