title: Real-time intraoperative visualization of myocardial circulation using augmented reality temperature display.
abstract: For direct visualization of myocardial ischemia during cardiac surgery, we tested the feasibility of presenting infrared (IR) tissue temperature maps in situ during surgery. A new augmented reality (AR) system, consisting of an IR camera and an integrated projector having identical optical axes, was used, with a high resolution IR camera as control. The hearts of five pigs were exposed and an elastic band placed around the middle of the left anterior descending coronary artery to induce ischemia. A proximally placed ultrasound Doppler probe confirmed reduction of flow. Two periods of complete ischemia and reperfusion were studied in each heart. There was a significant decrease in IR-measured temperature distal to the occlusion, with subsequent return to baseline temperatures after reperfusion (baseline 36.9 ± 0.60 (mean ± SD) versus ischemia 34.1 ± 1.66 versus reperfusion 37.4 ± 0.48; p < 0.001), with no differences occurring in the non-occluded area. The AR presentation was clear and dynamic without delay, visualizing the temperature changes produced by manipulation of the coronary blood flow, and showed concentrically arranged penumbra zones during ischemia. Surface myocardial temperature changes could be assessed quantitatively and visualized in situ during ischemia and subsequent reperfusion. This method shows potential as a rapid and simple way of following myocardial perfusion during cardiac surgery. The dynamics in the penumbra zone could potentially be used for visualizing the effect of therapy on intraoperative ischemia during cardiac surgery.
authors: Department of Thoracic and Cardiovascular Anesthesia/Intensive Care (IMH), County Council Östergötland, Linköping Heart Center, University Hospital, 581 85, Linköping, Sweden. zoltan.szabo@lio.se
authors: Zoltán
authors: Z
authors: Szabó
authors: Sören
authors: S
authors: Berg
authors: Stefan
authors: S
authors: Sjökvist
authors: Torbjörn
authors: T
authors: Gustafsson
authors: Per
authors: P
authors: Carleberg
authors: Magnus
authors: M
authors: Uppsäll
authors: Joakim
authors: J
authors: Wren
authors: Henrik
authors: H
authors: Ahn
authors: Örjan
authors: Ö
authors: Smedby
mesh_terms: D000818:Animals; D001831:Body Temperature; D006348:Cardiac Surgical Procedures; D003326:Coronary Circulation; D004195:Disease Models, Animal; D015150:Echocardiography, Doppler; D005240:Feasibility Studies; D006439:Hemodynamics; D007259:Infrared Rays; D016343:Monitoring, Intraoperative / Q000379:methods*; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D013552:Swine; D013817:Thermography; D013997:Time Factors