A system for evaluating a gastrointestinal tract of a subject, the system comprising: a medical device including an optical sensor, the optical sensor being configured to be placed in a lumen of the gastrointestinal tract to obtain data regarding tissue of the gastrointestinal tract; and a processor in communication with the medical device and configured to: receive, from the medical device, the data obtained by the optical sensor; using the obtained data, determine a measure of perfusion of blood in the tissue; using the obtained data, determine a measure of thickness of the tissue; using the measure of perfusion and the measure of thickness, determine a measure of inflammation of the tissue; and using one or more of the measure of perfusion, the measure of thickness, and the measure of inflammation, classify a state of the tissue, wherein the processor is configured such that determining a measure of inflammation comprises: applying a first function to the measure of perfusion, wherein applying the first function includes applying a sigmoid function comprising perfusion in the exponent; and applying a second function to the measure of thickness, wherein applying the second function includes applying a sigmoid function comprising thickness in the exponent, wherein when a change in measure of perfusion is in a higher severity category than a change in measure of thickness, then a tissue is flagged as fibrotic. a medical device including an optical sensor, the optical sensor being configured to be placed in a lumen of the gastrointestinal tract to obtain data regarding tissue of the gastrointestinal tract; and a processor in communication with the medical device and configured to: receive, from the medical device, the data obtained by the optical sensor; using the obtained data, determine a measure of perfusion of blood in the tissue; using the obtained data, determine a measure of thickness of the tissue; using the measure of perfusion and the measure of thickness, determine a measure of inflammation of the tissue; and using one or more of the measure of perfusion, the measure of thickness, and the measure of inflammation, classify a state of the tissue, receive, from the medical device, the data obtained by the optical sensor; using the obtained data, determine a measure of perfusion of blood in the tissue; using the obtained data, determine a measure of thickness of the tissue; using the measure of perfusion and the measure of thickness, determine a measure of inflammation of the tissue; and using one or more of the measure of perfusion, the measure of thickness, and the measure of inflammation, classify a state of the tissue, wherein the processor is configured such that determining a measure of inflammation comprises: applying a first function to the measure of perfusion, wherein applying the first function includes applying a sigmoid function comprising perfusion in the exponent; and applying a second function to the measure of thickness, wherein applying the second function includes applying a sigmoid function comprising thickness in the exponent, wherein when a change in measure of perfusion is in a higher severity category than a change in measure of thickness, then a tissue is flagged as fibrotic. applying a first function to the measure of perfusion, wherein applying the first function includes applying a sigmoid function comprising perfusion in the exponent; and applying a second function to the measure of thickness, wherein applying the second function includes applying a sigmoid function comprising thickness in the exponent, wherein when a change in measure of perfusion is in a higher severity category than a change in measure of thickness, then a tissue is flagged as fibrotic.