The evaluation of cardiac tamponade risk in patients with pericardial effusion detected by non-gated chest CT.

Background: Although pericardial effusion is often identified using non-gated chest computed tomography (CT), findings predictive of cardiac tamponade have not been adequately established.

Purpose: To determine the findings predictive of clinical cardiac tamponade in patients with moderate to large pericardial effusion using non-gated chest CT.

Material And Methods: We performed a retrospective analysis of 134 patients with moderate to large pericardial effusion who were identified from among 4581 patients who underwent non-gated chest CT. Cardiac structural changes, including right ventricular outflow tract (RVOT), were qualitatively evaluated. The inferior vena cava ratio with hepatic (IVCupp) and renal portions (IVClow) and effusion size were measured. The diagnostic performance of each structural change was calculated, and multivariate analysis was used to determine the predictors of cardiac tamponade.

Results: Of the 134 patients (mean age, 70.3 years; 64 men), 37 (28%) had cardiac tamponade. The sensitivity and specificity were 76% and 74% for RVOT compression; 87% and 84% for an IVClow ratio ≥0.77; and 60% and 77% for an effusion size ≥25.5 mm, respectively. Multivariate logistic regression analysis demonstrated that RVOT compression, an IVClow ratio ≥0.77, and an effusion size ≥25.5 mm were independent predictors of cardiac tamponade. The combination of these three CT findings had a sensitivity, specificity, and accuracy of 81%, 95%, and 91%, respectively.

Conclusion: In patients with moderate to large pericardial effusion, non-gated chest CT provides additional information for predicting cardiac tamponade.