CME Test for Internal to Common Carotid Artery Peak Systolic Velocity Ratios for Predicting North American Symptomatic Carotid Endarterectomy Trial Stenosis: Derivation/ Validation Study Using a Machine Learning Technique

2019 ◽  
Vol 43 (4) ◽  
pp. 200-200
2019 ◽  
Vol 43 (4) ◽  
pp. 182-185
Author(s):  
Alex Polak ◽  
Joseph F. Polak

The association between internal carotid artery/peak systolic velocity and stenosis severity as measured by the North American Symptomatic Carotid Endarterectomy Trial is known. The association of internal carotid artery peak systolic velocity to common carotid artery peak systolic velocity ratio is less well studied. We use a machine learning algorithm to study this association. We performed a meta-analysis of papers with point data showing graphs of internal carotid artery/peak systolic velocity ratio versus North American Symptomatic Carotid Endarterectomy Trial percent stenosis. We used a neural net algorithm to derive an equation relating internal carotid artery/common carotid artery peak systolic velocity to % stenosis in a derivation group (two thirds of the data points) and applied it to a validation subset (one third of the data points). Model performance was assessed by correlation coefficients and Bland-Altman analyses. We found 4 papers with appropriate data for a total of 775 data points. The mean % stenosis was 53% (26% SD) with a mean internal carotid artery/common carotid artery peak systolic velocity ratio of 3.9 (2.9 SD). The derivation data set (n = 516) showed an association with an r value of 0.76 ( P < .0001) between predicted and measured stenosis. Applying the derived equation to the validation subset (n = 259) showed a similar association ( r = 0.8; P < .0001). A machine learning algorithm gave a good approximation of the association between internal carotid artery/common carotid artery peak systolic velocity ratio and % stenosis on a continuous scale for the aggregate data of 4 published studies. These data could be used to study the accuracy of different cut-points for 50% and 70% stenosis in an unbiased fashion.


Vascular ◽  
2017 ◽  
Vol 25 (5) ◽  
pp. 553-556 ◽  
Author(s):  
John Phair ◽  
Eric B Trestman ◽  
Chetra Yean ◽  
Evan C Lipsitz

Background We report a symptomatic carotid web successfully treated with carotid endarterectomy. A healthy 43-year-old woman presented with acute-onset left-sided weakness. Carotid web was evident on computed tomography angiography as a focal filling defect in the right common carotid artery. This right common carotid artery web extended into the ICA created an eddy resulting in turbulent flow. Subsequent acute embolus formation led to embolization and acute stroke. Method Review of the literature was performed using Medline Plus and PubMed databases. Result The patient underwent carotid endarterectomy with primary closure. Procedure was well tolerated and there was an uneventful recovery. Conclusion Arterial webs are a rare arteriopathy and a usual arrangement of fibromuscular intralumenal in-growth with unclear etiology. It is however, an important potential etiology of stroke in patients without traditional atherosclerotic risk factors. Carotid web and atypical carotid fibromuscular dysplasia should be considered in young, otherwise healthy patients presenting with stroke and without the typical risk factors for atherosclerotic carotid disease and stroke.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sajida Perveen ◽  
Muhammad Shahbaz ◽  
Karim Keshavjee ◽  
Aziz Guergachi

Abstract Stratifying individuals at risk for developing diabetes could enable targeted delivery of interventional programs to those at highest risk, while avoiding the effort and costs of prevention and treatment in those at low risk. The objective of this study was to explore the potential role of a Hidden Markov Model (HMM), a machine learning technique, in validating the performance of the Framingham Diabetes Risk Scoring Model (FDRSM), a well-respected prognostic model. Can HMM predict 8-year risk of developing diabetes in an individual effectively? To our knowledge, no study has attempted use of HMM to validate the performance of FDRSM. We used Electronic Medical Record (EMR) data, of 172,168 primary care patients to derive the 8-year risk of developing diabetes in an individual using HMM. The Area Under Receiver Operating Characteristic Curve (AROC) in our study sample of 911 individuals for whom all risk factors and follow up data were available is 86.9% compared to AROCs of 78.6% and 85% reported in a previously conducted validation study of FDRSM in the same Canadian population and the Framingham study respectively. These results demonstrate that the discrimination capability of our proposed HMM is superior to the validation study conducted using the FDRSM in a Canadian population and in the Framingham population. We conclude that HMM is capable of identifying patients at increased risk of developing diabetes within the next 8-years.


Stroke ◽  
1992 ◽  
Vol 23 (8) ◽  
pp. 1048-1053 ◽  
Author(s):  
H J Barnett ◽  
R W Barnes ◽  
G P Clagett ◽  
G G Ferguson ◽  
J T Robertson ◽  
...  

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 111 ◽  
Author(s):  
Chul-Min Ko ◽  
Yeong Yun Jeong ◽  
Young-Mi Lee ◽  
Byung-Sik Kim

This study aimed to enhance the accuracy of extreme rainfall forecast, using a machine learning technique for forecasting hydrological impact. In this study, machine learning with XGBoost technique was applied for correcting the quantitative precipitation forecast (QPF) provided by the Korea Meteorological Administration (KMA) to develop a hydrological quantitative precipitation forecast (HQPF) for flood inundation modeling. The performance of machine learning techniques for HQPF production was evaluated with a focus on two cases: one for heavy rainfall events in Seoul and the other for heavy rainfall accompanied by Typhoon Kong-rey (1825). This study calculated the well-known statistical metrics to compare the error derived from QPF-based rainfall and HQPF-based rainfall against the observational data from the four sites. For the heavy rainfall case in Seoul, the mean absolute errors (MAE) of the four sites, i.e., Nowon, Jungnang, Dobong, and Gangnam, were 18.6 mm/3 h, 19.4 mm/3 h, 48.7 mm/3 h, and 19.1 mm/3 h for QPF and 13.6 mm/3 h, 14.2 mm/3 h, 33.3 mm/3 h, and 12.0 mm/3 h for HQPF, respectively. These results clearly indicate that the machine learning technique is able to improve the forecasting performance for localized rainfall. In addition, the HQPF-based rainfall shows better performance in capturing the peak rainfall amount and spatial pattern. Therefore, it is considered that the HQPF can be helpful to improve the accuracy of intense rainfall forecast, which is subsequently beneficial for forecasting floods and their hydrological impacts.


Author(s):  
Fahad Taha AL-Dhief ◽  
Nurul Mu'azzah Abdul Latiff ◽  
Nik Noordini Nik Abd. Malik ◽  
Naseer Sabri ◽  
Marina Mat Baki ◽  
...  

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