Predictors of inaccurate coronary arterial stenosis assessment by CT angiography

Abstract

Objectives: This study sought to investigate the clinical and imaging characteristics associated with diagnostic inaccuracy of computed tomography angiography (CTA) for detecting obstructive coronary artery disease (CAD) defined by quantitative coronary angiography (QCA).

Background: Although diagnostic performance metrics of CTA have been reported, there are sparse data on predictors of diagnostic inaccuracy by CTA.

Methods: The clinical characteristics of 291 patients (mean age: 59 ± 10 years; female: 25.8%) enrolled in the multicenter CorE-64 (Coronary Artery Evaluation Using 64-Row Multi-detector Computed Tomography Angiography) study were examined. Pre-defined CTA segment-level characteristics of all true-positive (N = 237), false-positive (N = 115), false-negative (FN) (N = 159), and a random subset of true-negative segments (N = 511) for ≥50% stenosis with QCA as the reference standard were blindly abstracted in a central core laboratory. Factors independently associated with corresponding levels of CTA diagnostic inaccuracies on a patient level and coronary artery segment level were determined using multivariable logistic regression models and generalized estimating equations, respectively.

Results: An Agatston calcium score of ≥1 per patient (odds ratio [OR]: 5.2; 95% confidence interval [CI]: 1.1 to 24.6) and the presence of within-segment calcification (OR: 10.2; 95% CI: 5.2 to 19.8) predicted false-positive diagnoses. Conversely, absence of within-segment calcification was an independent predictor of an FN diagnosis (OR: 2.0; 95% CI: 1.2 to 3.5). Prior percutaneous revascularization was independently associated with patient-level misdiagnosis of obstructive CAD (OR: 4.2; 95% CI: 1.6 to 11.2). Specific segment characteristics on CTA, notably segment tortuosity (OR: 3.5; 95% CI: 2.4 to 5.1), smaller luminal caliber (OR: 0.48; 95% CI: 0.36 to 0.63 per 1-mm increment), and juxta-arterial vein conspicuity (OR: 2.1; 95% CI: 1.4 to 3.2), were independently associated with segment-level misdiagnoses. Attaining greater intraluminal contrast enhancement independently lowered the risk of an FN diagnosis (OR: 0.96; 95% CI: 0.94 to 0.99 per 10-Hounsfield unit increment).

Conclusions: We identified clinical and readily discernible imaging characteristics on CTA predicting inaccurate CTA diagnosis of obstructive CAD defined by QCA. Knowledge and appropriate considerations of these features may improve the diagnostic accuracy in clinical CTA interpretation. (Diagnostic Accuracy of Multi-Detector Spiral Computed Tomography Angiography Using 64 Detectors [CORE-64]; NCT00738218).

Keywords: BMI; CAD; CI; CTA; FN; FP; OR; QCA; TN; TP; accuracy; body mass index; computed tomography angiography; confidence interval; coronary artery disease; false-negative; false-positive; odds ratio; quantitative coronary angiography; true-negative; true-positive.

Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

Panel A. An example of false-positive diagnoses by CT angiography at the mid left-anterior-descending artery (arrows) with focal tortuosity, motion and coronary calcification (proximal site) as well as poor contrast opacification in the distal portion.. Panel B. Corresponding conventional angiography without significant stenoses.

Figure 2

An example of conspicuous adjacent cardiac venous structure confounding coronary arterial interpretation. Panel A. Partial volume averaging effect by CT with adjacent cardiac vein mimicking focal non-calcified stenosis (first arrow) leading to false positive diagnosis. The distal arrow marks a false-negative diagnosis (CTA=15%, QCA=74% stenosis) masked by an adjacent cardiac vein. Panel B. Conventional angiography correlation revealing no stenosis at the proximal site but significant lesion at the distal site.

Figure 3

An example of poor contrast opacification leading to ambiguous lumen evaluation by CT. Panel A. Poor contrast filling of a proximal right coronary artery (arrow) does not allow visualization of a subtotal occlusion. Panel B. Corresponding invasive angiogram reveals severe lumen narrowing in the proximal right coronary artery (arrow).

Figure 4

Effect of cardiac motion on CT interpretation. A minor motion artifact leads to slightly smaller lumen appearance by CT (arrow, Panel A) compared to conventional angiography (arrow, Panel B) resulting in a false positive diagnosis of obstructive coronary artery disease.