Diagnostic value of chest radiography for pericardial effusion.

OBJECTIVES: This study was designed to determine the diagnostic value of chest radiography for pericardial effusion.
BACKGROUND: Pericardial effusions may cause life-threatening cardiac complications, yet they are often difficult to diagnose.
METHODS: In a blinded manner, we reviewed the chest radiographs of 83 patients with echocardiographically diagnosed pericardial effusions (5 large, 18 moderate, 60 small) and those of 17 control subjects without effusions. We examined four radiographic signs: an enlarged cardiac silhouette, a pericardial fat stripe, a predominant left-sided pleural effusion and an increase in transverse cardiac diameter compared with the diameter on a previous chest radiograph.
RESULTS: An enlarged cardiac silhouette was moderately sensitive (71%) but not specific (41%) for pericardial effusion. A pericardial fat stripe, a predominant left-sided pleural effusion and an increase in transverse cardiac diameter were all specific (94%, 100% and 80%, respectively) but not sensitive (12%, 20% and 46%, respectively). A predominant left-sided pleural effusion was associated with pericardial effusions of all sizes (odds ratio = 1.3, 95% confidence interval [CI] = 1.0-1.6, p = 0.04) and with large and moderate pericardial effusions alone (odds ratio = 7.7, 95% CI = 2.5-24.0, p = 0.0004). In contrast, a pericardial fat stripe was associated only with large and moderate pericardial effusions (odds ratio = 3.3, 95% CI = 0.9-12.0, p = 0.07), and an enlarged cardiac silhouette and an increase in cardiac diameter were not associated with pericardial effusion at all.
CONCLUSIONS: A predominant left-sided pleural effusion and a pericardial fat stripe are chest radiographic signs that are suggestive, but not diagnostic, of pericardial effusion. Because these signs cannot reliably confirm or exclude the presence of pericardial effusion, we conclude that chest radiography is poorly diagnostic of this condition.