Predictors of image quality of coronary computed tomography in the acute care setting of patients with chest pain

Abstract

Objective: We aimed to determine predictors of image quality in consecutive patients who underwent coronary computed tomography (CT) for the evaluation of acute chest pain.

Method and materials: We prospectively enrolled patients who presented with chest pain to the emergency department. All subjects underwent contrast-enhanced 64-slice coronary multi-detector CT. Two experienced readers determined overall image quality on a per-patient basis and the prevalence and characteristics of non-evaluable coronary segments on a per-segment basis.

Results: Among 378 subjects (143 women, age: 52.9+/-11.8 years), 345 (91%) had acceptable overall image quality, while 33 (9%) had poor image quality or were unreadable. In adjusted analysis, patients with diabetes, hypertension and a higher heart rate during the scan were more likely to have exams graded as poor or unreadable (odds ratio [OR]: 2.94, p=0.02; OR: 2.62, p=0.03; OR: 1.43, p=0.02; respectively). Of 6253 coronary segments, 257 (4%) were non-evaluable, most due to severe calcification in combination with motion (35%). The presence of non-evaluable coronary segments was associated with age (OR: 1.08 annually, 95%-confidence interval [CI]: 1.05-1.12, p<0.001), baseline heart rate (OR: 1.35 per 10 beats/min, 95%-CI: 1.11-1.67, p=0.003), diabetes, hypertension, and history of coronary artery disease (OR: 4.43, 95%-CI: 1.93-10.17, p<0.001; OR: 2.27, 95-CI: 1.01-4.73, p=0.03; OR: 5.12, 95%-CI: 2.0-13.06, p<0.001; respectively).

Conclusion: Coronary CT permits acceptable image quality in more than 90% of patients with chest pain. Patients with multiple risk factors are more likely to have impaired image quality or non-evaluable coronary segments. These patients may require careful patient preparation and optimization of CT scanning protocols.

Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Figures

Figure 1

Acceptable Image Quality Score of 1 to 3. Maximum intensity projection (MIP) images of the right coronary artery in a scan graded with a score of 1 for excellent (Figure 1A), score of 2 for good with mild blurring (Figure 1B), and score of 3 for fair image quality with moderate blurring and increased image noise (Figure 1C).

Figure 2

Poor or Unreadable Image Quality Score of 4 and 5. Maximum intensity projection (MIP) images of the right coronary artery in a scan graded with a score of 4 for poor image quality (Figure 2A) and a score of 5 for unreadable (Figure 2B).

Figure 3

Frequency of causes of non-evaluable coronary artery segments. Calcification and motion was the most frequent cause rending a segment non-evaluable (35%). CAC: coronary artery calcification, CNR: contrast-to-noise ratio.

Figure 4

Forrest plot showing clinical predictors of non-evaluable coronary segments (Odds Ratio with 95%-confidence intervals). Older patients (OR: 1.08 annually, 95%-CI: 1.05–1.12, p