Measurement Accuracy of Atherosclerotic Plaque Structure on CT Using Phantoms to Establish Ground Truth

Acad Radiol. 2017 Oct;24(10):1203-1215. doi: 10.1016/j.acra.2017.04.007. Epub 2017 May 24.


Rationale and objectives: The purpose of this study was to characterize analytic performance of software-aided arterial vessel structure measurements across a range of scanner settings for computed tomography angiography where ground truth is known. We characterized performance for measurands that may be efficiently measured for clinical cases without use of software, as well as those that may be done manually but which is generally not done due to the effort level required unless software is employed.

Materials and methods: Four measurands (lumen area, stenosis, wall area, wall thickness) were evaluated using tissue-mimicking phantoms to estimate bias, heteroscedasticity, and limits of quantitation both pooled across scanner settings and individually for eight different settings. Reproducibility across scanner settings was also estimated.

Results: Measurements of lumen area have a near constant bias of +1.3 mm for measurements ranging from 3 mm2 to 40 mm2; stenosis bias is +7% across a 30%-70% range; wall area bias is +14% across a 50-450 mm2 range; and wall thickness bias is +1.2 mm across a 3-9 mm range. All measurements possess properties that make them suitable for measuring longitudinal change. Lumen area demonstrates the most sensitivity to scanner settings (bias from as low as +.1 mm to as high as +2.7 mm); wall thickness demonstrates negligible sensitivity.

Conclusions: Variability across scanner settings for lumen measurands was generally higher than bias for a given setting. The converse was true for the wall measurands, where variability due to scanner settings was very low. Both bias and variability due to scanner settings of vessel structure were within clinically useful levels.

Keywords: CTA; atherosclerosis; plaque imaging; stenosis.

MeSH terms

  • Computed Tomography Angiography / instrumentation*
  • Computed Tomography Angiography / methods
  • Humans
  • Phantoms, Imaging*
  • Plaque, Atherosclerotic / diagnostic imaging*
  • Reproducibility of Results
  • Software