Abstract: Carotid artery stenosis (CAS) is a form of atherosclerosis, where thrombus formation restricts the passage of blood through the carotid artery leading to irreversible damage in the brain tissue. The presence of stenosis in the carotid artery results in abnormal temperature maps on the external skin surface, which can be captured and quantified using non-contact/non-invasive infrared (IR) thermal imaging/thermography. In this study, a thermally charged in-vitro carotid artery flow loop, using 0% and 75% stenosis models, was designed to study the thermal effect on the external skin surface. The carotid artery flow was encapsulated with PDMS (polydimethylsiloxane) resembling neck tissue, of which the external surface temperature maps were studied using IR thermography. Using the mean temperature as a threshold value, the resultant thermal image was processed and normalized. Between the two stenosis models, disruption in the thermal features corresponding to the presence of stenosis was observed. The method described in this study paves the path to experimentally study the thermal effect of the presence of stenosis in the carotid artery.

Keywords: Atherosclerosis; Carotid artery stenosis; Conjugate bio-heat transfer; Infrared (IR) thermal imaging; Thermography; Thermal region of interest (TROI)

Technical Disclosure/Copyright:

1. Ashish Saxena, E.Y.K. Ng, and Lim Soo Teik. “Neck Thermography for a Non-contact/Non-invasive Screening of Patients with Carotid Artery Stenosis”, NTUitive Pte. Ltd., Singapore (Ref. no.: 2019-046).
2. Ashish Saxena, E.Y.K. Ng, Vignesh Raman, and Lim Soo Teik. “Thermography based superficial vein projection system to ease real-time vein puncturing”, NTUitive Pte. Ltd., Singapore (Ref. no.: 2018-150).

1. Ashish Saxena, Vedabit Saha, E.Y.K. Ng, “Skin temperature maps as a measure of carotid artery stenosis”, Computers in Biology and Medicine (2020): 116, 103548 (13 pages), https://doi.org/10.1016/j.compbiomed.2019.103548.
2. Ashish Saxena, E.Y.K. Ng, Vignesh Raman, Muhammad Syarifuddin Bin Mohamed Hamli, Mateusz Moderhak, Szymon Kolacz, and Jerzy Jankau. "Infrared (IR) Thermography-based Quantitative Parameters to Predict the Risk of Post-operative Cancerous Breast Resection Flap Necrosis." Infrared Physics & Technology (2019): 103, 103063 (12 pages), https://doi.org/10.1016/j.infrared.2019.103063.
3. Ashish Saxena, E.Y.K. Ng, Soo Teik Lim, " Infrared (IR) thermography as a potential screening modality for carotid artery stenosis", Computers in Biology and Medicine (2019):113, 103419 (11 pages), https://doi.org/10.1016/j.compbiomed.2019.103419.
4. Ashish Saxena, E.Y.K. Ng, Mrudang Mathur, Chirag Manchanda, and Nehal Amit Jajal, "Effect of carotid artery stenosis on neck skin tissue heat transfer." International Journal of Thermal Sciences 145 (2019): 106010, https://doi.org/10.1016/j.ijthermalsci.2019.106010.
5. Ashish Saxena, E.Y.K. Ng, and Lim Soo Teik. "Imaging modalities to diagnose carotid artery stenosis: progress and prospect." BioMedical Engineering OnLine 18.1 (2019): 66, https://doi.org/10.1186/s12938-019-0685-7.
6. Ashish Saxena, Vignesh Raman, and E.Y.K. Ng. “Study on methods to extract high contrast image in active dynamic thermography”, Quantitative InfraRed Thermography Journal (2019): 1-17, Taylor & Francis Online, https://doi.org/10.1080/17686733.2019.1586376.
7. Ashish Saxena, E.Y.K. Ng, and Vignesh Raman, “Single Image Reconstruction in Active Dynamic Thermography: A Novel Approach”, Infrared Physics & Technology 93 (2018): 53-58, https://doi.org/10.1016/j.infrared.2018.07.020.
8. Ashish Saxena, E.Y.K. Ng, and Vignesh Raman. "Thermographic Venous Blood Flow Characterization with External Cooling Stimulation." Infrared Physics & Technology 90 (2018): 8-19, https://doi.org/10.1016/j.infrared.2018.02.001.
9. Tejas Canchi, Ashish Saxena, E.Y.K. Ng, and Sriram Narayanan. “Application of Fluid Structure Interaction Methods to estimate the mechanics of rupture in Abdominal Aortic Aneurysms”, BioNanoScience 8.4 (2018): 1035-1044, https://doi.org/10.1007/s12668-018-0554-z.
10. Ashish Saxena and E.Y.K. Ng, “Steady and Pulsating Flow past a Heated Rectangular Cylinder(s) in a Channel”, Journal of Thermophysics and Heat Transfer 32.2 (2017): 401-413, https://doi.org/10.2514/1.T5265.
11. A Saxena, EYK Ng, T Canchi, JL Lim, AS Beruvar, "A Method to Produce High Contrast Vein Visualization in Active Dynamic Thermography (ADT)", Journal of Medical Systems (2020) JOMS-D-20-00778, (in-press).
12. A Saxena, EYK Ng, T Canchi, JJ Tee, LK Ng, “Relation between neck skin temperature measurement and carotid artery stenosis: in-vitro and in-vivo evaluation”, ASME Journal of Biomechanical Engineering. Vol. 142, 2020, pp. 114501-1, 8 pages, https://doi.org/10.1115/1.4048423.
13. Ashish Saxena, EYK Ng, C Manchanda, Tejas Canchi, “Cardiac Thermal Pulse at the Neck Skin Surface as a Measure of Stenosis in the Carotid Artery”. Thermal Science and Engineering Progress Journal, 100603 (8 pages), 2020 Elsevier, https://doi.org/10.1016/j.tsep.2020.100603.
14. Ashish Saxena, Ng, E. Y-K, Lim ST, “Active Dynamic Thermography to Predict the Presence of Stenosis in the Carotid Artery." Computers in Biology and Medicine, (2020), Vol. 120, pp. 103718 (9 pages), Elsevier, https://doi.org/10.1016/j.compbiomed.2020.103718.

Biography: Ng obtained Ph.D. at Cambridge Univ. and elected as a Fellow of The American Society of Mechanical Engineers; The Institution of Engineering and Technology [UK], and International Engineering & Technology Institute [HK]. He researches in numerical simulation in the biomedical engineering, thermal-fluids and health-related diagnosis fields. He is Editor-in-Chief for 2 ISI-journals which were captured by the JCR within 2-years of their inauguration. He has been recognized internationally for academic excellence. He received numerous best papers, service awards and has graduated 23 PhD and 26 Master students. He was awarded the SPRING-Singapore Merit Award for his work in thermal imagers to screen SARS fever and contributions to the Singapore Standardization Program. Twenty-one of his papers have been adopted as references in Singapore Standard (SS-582, Parts 1&2: 2020) and ISO/IEC 80601-2-59: 2017. He serves as a panel member for Singapore Biomedical and Health Standards Committee since 2011. Being a co-inventor of 3 US patents on software classifiers to identify the different stages of breast cancer development in iTBra-system, he was accoladed with equity in a listed company. His ongoing work on non-contact screening for carotid artery stenosis and superficial vein-finder has resulted in 3 TDs. He has notable citations in the field of infrared physics & technology.