Precision and accuracy of cross-sectional area measurements used to measure coronary endothelial function with spiral MRI

Michael Schär, Sahar Soleimanifard, Gabriele Bonanno, Jérôme Yerly, Allison G. Hays, Robert G. Weiss

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: Coronary endothelial function (CEF) reflects vascular health and conventional invasive CEF measures predict cardiovascular events. MRI can now noninvasively measure CEF by quantifying coronary artery cross-sectional area changes in response to isometric handgrip exercise, an endothelial-dependent stressor. Area changes (10 to 20% in healthy; 2 to −12% in impaired vessels) are only a few imaging voxels because of MRI's limited spatial resolution. Here, with numerical simulations and phantom studies, we test whether Fourier interpolation enables sub-pixel area measurement precision and determine the smallest detectable area change using spiral MRI. Methods: In vivo coronary SNR with the currently used CEF protocol at 3T was measured in 7 subjects for subsequent in vitro work. Area measurements of circular vessels were simulated by varying partial volume, vessel diameter, voxel size, SNR, and Fourier interpolation factor. A phantom with precision-drilled holes (diameters 3–3.42 mm) was imaged 10 times with the current CEF protocol (voxel size, Δx = 0.89 mm) and a high-resolution protocol (Δx = 0.6 mm) to determine precision, accuracy, and the smallest detectable area changes. Results: In vivo coronary SNR ranged from 30–76. Eight-fold Fourier interpolation improved area measurement precision by a factor 6.5 and 4.9 in the simulations and phantom scans, respectively. The current CEF protocol can detect mean area changes of 4–5% for SNR above 30, and 3–3.5% for SNR above 40 with a higher-resolution protocol. Conclusion: Current CEF spiral MRI with in vivo SNR allows detection of a 4–5% area change and Fourier interpolation improves precision several-fold to sub-voxel dimensions.

Original languageEnglish (US)
Pages (from-to)291-302
Number of pages12
JournalMagnetic resonance in medicine
Volume81
Issue number1
DOIs
StatePublished - Jan 2019

Keywords

  • Fourier interpolation
  • MRI
  • coronary endothelial function
  • cross-sectional area measurement, vasodilation
  • spiral

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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