Estimation of coronary blood flow by ECG gated cardiac thermography in open-chest conditions

Na'ama Gordon, Shmuel Rispler, Samuel Sideman, Rona Shofti, Rafael Beyar

Research output: Contribution to journalArticlepeer-review

Abstract

Thermography is suggested as a tool to estimate myocardial and coronary epicardial flow in open-chest heart surgery. To test the feasibility and compare various methods for coronary flow estimation in open-chest surgery, thermographic imaging was applied to eight open-chest dogs which were injected with cold saline into the aortic root. Blood flow in the left arterial descending (LAD) coronary vessel was measured by a transit-time flowmeter. ECG gated images were acquired for 20-30 s, while the cold saline (20 ml) was injected into the aortic root. Several flow levels were achieved during repeated hyperaemic response to transient occlusions of the LAD. A temperature response curve for each flow level was obtained by averaging over an edge-detected arterial segment for each image frame. Several indices were calculated from the temperature curve and correlated with the measured coronary flow. These include: an index based on a corrective heat transfer model (r = 0.69, p <0.001), the slope of the descending part of the response curve (r = 0.76, p <0.001), the peak temperature difference (r = 0.66, p <0.001), and the area above the temperature response curve (r = 0.61, p <0.01). As shown, coronary flow can be estimated quantitatively by intraoperative epicardial thermography, and may therefore provide important on-line information regarding blood flow during open-chest surgical procedures. Further studies are required for optimal application of this technique so as to increase its potential as a valid clinical tool.

Original languageEnglish (US)
Pages (from-to)353-366
Number of pages14
JournalPhysiological Measurement
Volume19
Issue number3
DOIs
StatePublished - 1998
Externally publishedYes

Keywords

  • Blood flow
  • Coronary arteries
  • Thermography

ASJC Scopus subject areas

  • Biophysics

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