In the study protocol includes invasive/non-invasive data collection from Common Carotid Artery (CCA) through three different techniques: 1. Conventional and widely available routine methods (both invasive and non-invasive); 2. Passive thermography (Non-invasive and non-contact); 3. Active thermography with cold stimulation (Non-invasive and minimally contact). For this purpose 100 human subject (both male and female) with normal and stenosis carotid artery will be recruited in the age group of 35-70 years to establish the baseline for healthy subjects as well as contrasting the diagnosis for the mostly diseased aged subjects. It is well established that skin thermal properties and blood vessel size also varies with age which justifies the wide age group selection for the study. It is believed that the study will give an invaluable and significant set of data for the further development of a diagnosis instrument.