A Noninvasive Assessment of Flow Based on Contrast Dispersion in Computed Tomography Angiography: A Computational and Experimental Phantom Study

Parastou Eslami, Jung Hee Seo, Amir Ali Rahsepar, Asim Shafique, Shirley F. Rollison, Albert C. Lardo, Rajat Mittal, Marcus Y. Chen

Research output: Contribution to journalArticlepeer-review

Abstract

Transluminal attenuation gradient (TAG), defined as the gradient of the contrast agent attenuation drop along the vessel, is an imaging biomarker that indicates stenosis in the coronary arteries. The transluminal attenuation flow encoding (TAFE) equation is a theoretical platform that quantifies blood flow in each coronary artery based on computed tomography angiography (CTA) imaging. This formulation couples TAG (i.e., contrast dispersion along the vessel) with fluid dynamics. However, this theoretical concept has never been validated experimentally. The aim of this proof-of-principle phantom study is to validate TAFE based on CTA imaging. Dynamic CTA images were acquired every 0.5 s. The average TAFE estimated flow rates were compared against four predefined pump values in a straight (20, 25, 30, 35, and 40 ml/min) and a tapered phantom (25, 35, 45, and 55 ml/min). Using the TAFE formulation with no correction, the flow rates were underestimated by 33% and 81% in the straight and tapered phantoms, respectively. The TAFE formulation was corrected for imaging artifacts focusing on partial volume averaging and radial variation of contrast enhancement. After corrections, the flow rates estimated in the straight and tapered phantoms had an excellent Pearson correlation of r = 0.99 and 0.87 (p < 0.001), respectively, with only a 0.6%±0.2 mL/min difference in estimation of the flow rate. In this proof-of-concept phantom study, we corrected the TAFE formulation and showed a good agreement with the actual pump values. Future clinical validations are needed for feasibility of TAFE in clinical use.

Original languageEnglish (US)
JournalJournal of Biomechanical Engineering
Volume144
Issue number9
DOIs
StatePublished - Sep 1 2022
Externally publishedYes

Keywords

  • contrast agent
  • coronary computed tomography
  • noninvasive flow rate
  • time density
  • transluminal attenuation gradient
  • transluminal flow encoding

ASJC Scopus subject areas

  • Physiology (medical)
  • Biomedical Engineering

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