Problems and Pitfalls in the Echocardiographic Assessment of Pericardial Effusion

Abstract

The echocardiographic diagnosis of pericardial effusions is usually based on visualization of a sonolucent circumcardiac space of varying width. However, potential fallacies in interpretation can arise if sonolucent spaces adjacent to the heart (pleural effusions, ascites, pericardial cysts) are mistaken for pericardial effusions. Loculated pericardial effusions, especially if unusual in location or configuration, can cause diagnostic difficulty on occasion. The differential diagnosis of various "solid" echoes within a pericardial effusion is of clinical relevance, yet not widely discussed. Inflammatory tissue, neoplastic involvement, pus, caseous material, and extravasated blood all have characteristic echocardiographic morphologies. All of the various reported echocardiographic signs of tamponade do not have the same significance, so that caution is necessary not to over- or under-read tamponade. Chamber collapse can be absent in real tamponade in specific situations. On the other hand, "regional" tamponade can occur if loculated pericardial effusions are sufficiently large and high tension; echocardiographic appearances are "atypical" but diagnostically valuable if correctly interpreted. These and certain other unusual variants of tamponade deserve to be better known among echocardiographers not only because of their intrinsic interest, but also to avoid potential pitfalls in the echocardiographic assessment of patients with suspected disease.

Imaging Findings in Cardiac Tamponade with Emphasis on CT

“…CT also allows differentiation of pericardial thickening from pericardial fluid owing to the occasional presence of nodular areas of increased attenuation in pericardial thickening, the typical anterior location of the thickened pericardium, lack of change at decubitus positioning, and pericardial enhancement with administration of contrast material (26). Occasionally, this differentiation can be difficult, particularly in cases of small pericardial collections (27,28).…”

“…Other limitations include the difficulty of identifying clotting or clots within the pericardium at echocardiography as well as differentiation of small fluid collections from pericardial thickening, differentiation of fluid in the anterior and posterior spaces around the heart from epicardial fat, and identification of loculations in complex pericardial collections (8,26,27).…”

Pericardial Disease: Value of CT and MR Imaging

“…However, echocardiography may fail to allow adequate evaluation of the pericardium at times. In particular, the diagnostic accuracy of echocardiography is limited in patients with a suboptimal acoustic window (eg, obese subjects, patients with severe chronic obstructive pulmonary disease or skeletal malformations) (9,10). Moreover, transthoracic echocardiography is limited in its ability to aid in recognition of focal effusions, assessment of pericardial thickness, and characterization of tissue (10,11).…”

Pericardial hematoma mimicking pericardial abscess

“…An exudative pericardial effusion may show features such as stranding, adhesions, or an uneven distribution reflecting its more inflammatory and complicated nature 1. Pericardial hematomas manifest as “solid” echogenic material, representing clotted or at least extravasated blood, with or without some component of sonolucent adjacent pericardial space 2. Pericardial “thrombus” layers may show mobility 2.…”