Application—Infrared Thermal Imaging and Doppler Vessel Pressurization Ultrasonography to Detect Lower Extremity Deep Vein Thrombosis

Infrared Thermal Imaging and Doppler Vessel Pressurization Ultrasonography to Detect Lower Extremity Deep Vein Thrombosis

   Pulmonary thromboembolism (PTE) and deep vein thrombosis (DVT) of the lower limbs belong to the overall group of venous thromboembolisms (VTEs). Among the more than million DVT sufferers with a confirmed diagnosis, about 25% die from a PTE, and as many as 50% had already developed their PTE, which appeared as the initial symptom. We therefore propose a simple, noncontact, non-radiation, harmless, adjunctive diagnostic screening measure for patients highly suspected of having a DVT and those who do not have a DVT but are at high risk of developing one.

   IRTI is a functional thermal imaging detection system, with the help of an infrared non-cooled camera, it captures, records, and measures the infrared radiation being emitted from the human body’s surface and can detect its surface temperature. Because of the development of infrared non-refrigerated lenses, high-resolution digitization picture, and infrared thermal imaging analytic software and because of its advantages of low cost, noninvasiveness, and noncontact IRTI has been gradually applied in man medical fields. 

Figure 1. Infrared thermography of normal patients

   The detection ability of IRTI is based on physiology. Here, the functional properties of the human body can be observed by infrared heat (of varying degree) radiating from the human body that accurately reflects the features and regularity at the cellular metabolic level. Considering the fact that functional change is controlled by the dynamic process of human physiology, no matter how sophisticated the human body is, all of the heat in the inner body transfers to the surface. Hence, dynamic observation of human body function is more premonitory than static.

Figure 2. Positive patients show higher temperature

   An IRTI system could precisely measure and store real-time thermal images. We conducted a double-blind, controlled clinical study using IRTI and detection on 157 patients with suspected DVTs, evaluating the following parameters: sensitivity, specificity, positive prescreening, negative prescreening, false positivity, false negativity, and diagnostic accordance of IRTI with CPUS for detecting DVT. Of 140 subjects who underwent screening both IRTI and CPUS detect were included for analyses. IRTI results accorded with CPUS results except for the positivity incidence.

   Thus, IRTI could be used for detecting DVTs and adjunctive diagnostic screening, and the effective combination of IRTI and CPUS detection would be of great value for early-stage detection and definitive diagnosis of DVT.

Reference

Fangge Deng, Qing Tang, Mei Jiang, et al. Infrared thermal imaging and Doppler vessel pressurization ultrasonography to detect lower extremity deep vein thrombosis: diagnostic accuracy study. Clinical Respiratory Journal, 2017.