Toward automated classification of pathological transcranial Doppler waveform morphology via spectral clustering

PLoS One

article

Samuel G. Thorpe¹  Corey M. Thibeault¹  Nicolas Canac¹  Kian Jalaleddini¹  Amber Dorn¹  Seth J. Wilk¹  Thomas Devlin²  Fabien Scalzo³  Robert B. Hamilton¹ 

[1]Department of Research, Inc.

[2]Department of Neurology, Erlanger Medical Center

[3]Department of Neurology, University of California Los Angeles

DOI  :  10.1371/journal.pone.0228642

学科分类：急救医学

来源: Public Library of Science

【 摘 要 】

Cerebral Blood Flow Velocity waveforms acquired via Transcranial Doppler (TCD) can provide evidence for cerebrovascular occlusion and stenosis. Thrombolysis in Brain Ischemia (TIBI) flow grades are widely used for this purpose, but require subjective assessment by expert evaluators to be reliable. In this work we seek to determine whether TCD morphology can be objectively assessed using an unsupervised machine learning approach to waveform categorization. TCD beat waveforms were recorded at multiple depths from the Middle Cerebral Arteries of 106 subjects; 33 with Large Vessel Occlusion (LVO). From each waveform, three morphological features were extracted, quantifying onset of maximal velocity, systolic canopy length, and the number/prominence of peaks/troughs. Spectral clustering identified groups implicit in the resultant three-dimensional feature space, with gap statistic criteria establishing the optimal cluster number. We found that gap statistic disparity was maximized at four clusters, referred to as flow types I, II, III, and IV. Types I and II were primarily composed of control subject waveforms, whereas types III and IV derived mainly from LVO patients. Cluster morphologies for types I and IV aligned clearly with Normal and Blunted TIBI flows, respectively. Types II and III represented commonly observed flow-types not delineated by TIBI, which nonetheless deviate from normal and blunted flows. We conclude that important morphological variability exists beyond that currently quantified by TIBI in populations experiencing or at-risk for acute ischemic stroke, and posit that the observed flow-types provide the foundation for objective methods of real-time automated flow type classification.

【 授权许可】

CC BY