title: In vivo detection of atherosclerotic plaque using non-contact and label-free near-infrared hyperspectral imaging.
abstract: Detecting detailed atherosclerotic plaques is important to reduce risk factors during surgery. However, there are few methods to evaluate them during surgery. The aim of this study was to establish an in vivo, non-contact, and label-free imaging method for identifying atherosclerotic plaque lesions from outside vessels with a diffuse-reflectance near-infrared (NIR) hyperspectral imaging (HSI) system.
  
  
  
  NIR spectra between 1000 and 2350 nm were measured using an NIR HSI imaging system outside the exposed abdominal aorta in five Watanabe Heritable Hyperlipidemic (WHHL) rabbits in vivo. Preprocessed data were input to a supervised machine learning algorithm called a support vector machine (SVM) to create pixel-based images that can predict atherosclerotic plaques within a vessel. The images were compared with histological findings.
  
  
  
  Absorbance was significantly higher in plaques than in normal arteries at 1000-1380, 1580-1810, and 1880-2320 nm. Overall predictive performance showed a sensitivity of 0.814 ± 0.017, a specificity of 0.836 ± 0.020, and an accuracy of 0.827 ± 0.008. The area under the receiver operating characteristic curve was 0.905 (95% confidence interval = 0.904-0.906).
  
  
  
  The NIR HSI system combined with a machine learning algorithm enabled accurate detection of atherosclerotic plaques within an internal vessel with high spatial resolution from outside the vessel. The findings indicate that the NIR HSI system can provide non-contact, label-free, and precise localization of atherosclerotic plaques during vascular surgery.
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: dollmaster213@yahoo.co.jp.
authors.forename: Hideo
authors.initials: H
authors.lastname: Chihara
authors.affiliation: Human Brain Research Center, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan; Department of Psychiatry, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: noishi@kuhp.kyoto-u.ac.jp.
authors.forename: Naoya
authors.initials: N
authors.lastname: Oishi
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: ishiiakira@gmail.com.
authors.forename: Akira
authors.initials: A
authors.lastname: Ishii
authors.affiliation: Department of Neurosurgery, Shiga Medical Center for Adults, 5-4-30 Moriyama, Moriyama-shi, Shiga, 524-8524, Japan. Electronic address: evzwnb5150@gmail.com.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Munemitsu
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: adaisuke1981@gmail.com.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Arai
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: rocky@kuhp.kyoto-u.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ikeda
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: miy@kuhp.kyoto-u.ac.jp.
authors.forename: Susumu
authors.initials: S
authors.lastname: Miyamoto
mesh_terms: D000465:Algorithms; D000818:Animals; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D019540:Area Under Curve; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D012372:ROC Curve; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
keywords: Atherosclerosis; Atherosclerotic plaque; Hyperspectral imaging; Near-infrared; Non-contact; Support vector machine