Diagnostic performance of chest radiography measurements for the assessment of cardiac chamber enlargement.

BACKGROUND: The cardiothoracic ratio (CTR) is commonly assessed on chest radiography for detection of cardiac chamber enlargement, but the traditional cutpoint of 0.5 has low specificity. We sought to evaluate the diagnostic accuracy of new measurement techniques for the detection of cardiac enlargement on chest radiographs. METHODS: We obtained retrospective cross-sectional data on consecutive patients who underwent both chest radiography and cardiac magnetic resonance imaging (MRI) within a 14-day interval between 2006 and 2016 at a large academic hospital network. We established the presence of cardiac chamber enlargement using cardiac MRI as the reference standard. We evaluated the diagnostic performance of different techniques for measuring heart size and CTR on frontal chest radiographs. RESULTS: Of 152 patients included, 81 (53%) were men and the mean age was 52 years. Maximum heart diameter had the highest area under the receiver operating characteristic curve for detection of cardiac enlargement (0.827, 95% confidence interval 0.760-0.894). In the subgroup of posteroanterior chest radiography studies (n = 101), a CTR cutpoint of 0.50 had only moderate sensitivity (72%) and specificity (72%). In men, a maximum heart diameter cutpoint of 15 cm had a sensitivity of 86% and a negative likelihood ratio of 0.24, and a cutpoint of 19 cm had a specificity of 100% and a positive likelihood ratio of infinity. In women, a maximum heart diameter cutpoint of 13 cm had a sensitivity of 91% and a negative likelihood ratio of 0.15, and a cutpoint of 17 cm had a specificity of 91% and a positive likelihood ratio of 3.5. INTERPRETATION: A traditional CTR cutpoint of 0.5 has limited diagnostic value. Simple heart diameter measurements have higher diagnostic performance measures than CTR.

Diagnostic Accuracy of Sex-Specific Chest CT Measurements Compared With Cardiac MRI Findings in the Assessment of Cardiac Chamber Enlargement.

OBJECTIVE: The purpose of this study was to establish sex-specific chest CT measurement thresholds for detection of cardiac chamber enlargement with cardiac MRI as the reference standard. MATERIALS AND METHODS: Consecutive patients who underwent contrast-enhanced chest CT (64- or 320-MDCT) and cardiac MRI within a 7-day interval between August 2006 and August 2016 were included in this retrospective study (n = 217; 115 men, 102 women; mean age, 52.8 ± 15.8 years). Measurements were performed on axial CT images to evaluate right atrial (RA), right ventricular (RV), left atrial (LA), and left ventricular (LV) chamber size. The presence of chamber enlargement (RAE, RVE, LAE, and LVE) was established with cardiac MRI as the reference standard. ROC analysis was performed. Optimal sex-specific CT measurement thresholds were identified that ensured specificity of 90% or greater and maximized sensitivity. RESULTS: The prevalence of chamber enlargement in men was 26% for RAE, 11% for RVE, 40% for LAE, and 24% for LVE. In women the prevalence was 16% for RAE, 15% for RVE, 27% for LAE, and 12% for LVE. The following CT measurement thresholds were optimal: for RAE, RA transverse diameter ≥ 67 mm for men (AUC, 0.825) and ≥ 64 mm for women (AUC, 0.926); for RVE, RV transverse diameter ≥ 60 mm for men (AUC, 0.846) and ≥ 57 mm for women (AUC, 0.858); for LAE, LA anteroposterior diameter ≥ 50 mm for men (AUC, 0.795) and ≥ 45 mm for women (AUC, 0.841); for LVE, LV transverse diameter ≥ 58 mm for men (AUC, 0.917) and ≥ 53 mm for women (AUC, 0.840). CONCLUSION: Cardiac chamber enlargement can be identified with high specificity and reasonable sensitivity on axial chest CT images by use of sex-specific measurement thresholds.

Measuring Left Ventricular Size in Non-Electrocardiographic-gated Chest Computed Tomography: What Radiologists Should Know.

Non-electrocardiographic (ECG)-gated computed tomography (CT) of the chest is one of the most commonly performed imaging studies. Although the heart is included in every CT study, cardiac findings are commonly underreported in radiology reports. Left ventricular size is one of the most important prognostic markers in multiple cardiac diseases and can be measured on almost all non-ECG-gated multidetector chest CT studies. This review will discuss the available evidence on different measurements of left ventricular size obtained on non-ECG-gated CT of the chest. Measurement thresholds, technical issues, and potential problems are emphasized, with practical recommendations.