Pericardial fat mimicking pericardial effusion on two-dimensional echocardiography

Blood or Fat? Differentiating Hemopericardium versus Epicardial Fat Using Focused Cardiac Ultrasound

Basic point-of-care ultrasound of the heart-also known as Focused Cardiac Ultrasound (FoCUS)-has emerged as a powerful bedside tool to narrow the differential diagnosis of causes of hypotension. The list of causes of hypotension that a FoCUS provider is expected to be able to recognize includes a compressive pericardial effusion due to hemopericardium (blood in the pericardial sac). But hemopericardium can be difficult to distinguish from a more common condition that is not immediately life-threatening: epicardial fat. This paper reviews illustrative images of both epicardial fat and hemopericardium to provide practice guidance to the FoCUS user on how to differentiate these two phenomena.

eFAST exam errors at a level 1 trauma center: A retrospective cohort study

OBJECTIVES

Extended Focused Assessment with Sonography for Trauma (eFAST) ultrasound exams are central to the care of the unstable trauma patient. We examined six years of eFAST quality assurance data to identify the most common reasons for false positive and false negative eFAST exams.

METHODS

This was an observational, retrospective cohort study of trauma activation patients evaluated in an urban, academic Level 1 trauma center. All eFAST exams that were identified as false positive or false negative exams compared with computed tomography (CT) imaging were included.

RESULTS

4860 eFAST exams were performed on trauma patients. 1450 (29.8%) were undocumented, technically limited, or incomplete (missing images). Of the 3410 remaining exams, 180 (5.27%) were true positive and 3128 (91.7%) were true negative. 27 (0.79%) exams were identified as false positive and 75 (2.19%) were identified as false negative. Of the false positive scans, 7 had no CT scan and 8 had correct real-time trauma paper documentation of eFAST exam results when compared to CT and were excluded, leaving 12 false positive scans. Of the false negative scans, 11 were excluded for concordant documentation in real-time trauma room paper documentation, 20 were excluded for no CT scan, and 2 were excluded as incomplete, leaving 42 false negative scans. Pelvic fluid, double-line sign, pericardial fat pad, and the thoracic portion of the eFAST exam were the most common source of errors.

CONCLUSION

The eFAST exams in trauma activation patients are highly accurate. Unfortunately poor documentation and technically limited/incomplete studies represent 29.8% of our eFAST exams. Pelvic fluid, double-line sign, pericardial fat pad, and the thoracic portion of the eFAST exam are the most common source of errors.

Echocardiography practice: insights into appropriate clinical use, technical competence and quality improvement program

Echocardiography accounts for nearly half of all cardiac imaging techniques. It is a widely available and adaptable tool, as well as being a cost-effective and mainly a non-invasive test. In addition, echocardiography provides extensive clinical data, which is related to the presence or advent of different modalities (tissue Doppler imaging, speckle tracking imaging, three-dimensional mode, contrast echo, etc.), different approaches (transesophageal, intravascular, etc.), and different applications (ie, heart failure/resynchronization studies, ischemia/stress echo, etc.). In view of this, it is essential to conform to criteria of appropriate use and to keep standards of competence. In this study, we sought to review and discuss clinical practice of echocardiography in light of the criteria of appropriate clinical use, also we present an insight into echocardiographic technical competence and quality improvement project.

MR, CT, and PET imaging in pericardial disease

Although echocardiography remains the standard diagnostic tool for identifying pericardial diseases, procedures with better delineation of morphology and heart function are often required. The pericardium consists of an inner visceral (epicardium) and outer parietal layer (pericardium), which constitute for the pericardial cavity. Pericardial effusion can occur as transudate, exudate, pyopneumopericardium, or hemopericardium. Potential causes are inflammatory processes, that is, pericarditis due to autoimmune or infective reasons, neoplasms, irradiation, or systemic disorders, chronic renal failure, endocrine, or metabolic diseases. Pericardial fat can mimic pericardial effusion. Using various image-acquisition sequences, MRI allows identifying and separating fluid and solid structures. Fast spin-echo T1-weighted sequences with black-blood preparation are favourably used for morphological evaluation. Fast spin-echo T2-weighted sequences, particularly with fat saturation, and short-tau inversion-recovery sequences are useful to visualize oedema and inflammation. For further tissue characterization, delayed inversion-recovery imaging is used. Therefore, image acquisition is performed at 5-20 min subsequent to contrast agent administration, the so-called technique of late gadolinium enhancement. Ventricular volumes and myocardial mass can be assessed accurately by steady-state free-precession sequences, which is required to measure cardiac function and ventricular wall stress. Constrictive pericarditis usually results from chronic inflammatory processes leading to increased stiffness, which impedes the slippage of both pericardial layers and thereby the normal cardiac filling. CT imaging can favourably assess pericardial calcification. Thus, MR and CT imaging allow a comprehensive delineation of the pericardium. Superior to echocardiography, both methods provide a larger field of view and depiction of the complete chest including abnormalities of the surrounding mediastinum and lungs. PET provides unique information on the in vivo metabolism of 18-fluorodeoxyglucose that can be superimposed on CT findings and is useful for identifying inflammatory processes or masses, for example neoplasms. These imaging techniques provide advanced information of anatomy and cardiac function to optimize the pericardial access, for example by the AttachLifter system, for diagnosis and treatment.

Pseudo cardiac tamponade in the setting of excess pericardial fat

Cardiac tamponade is the phenomenon of hemodynamic compromise caused by a pericardial effusion. Following a myocardial infarction, the most common causes of pericardial fluid include early pericarditis, Dressler's syndrome, and hemopericardium secondary to a free wall rupture. On transthoracic echocardiography, pericardial fluid appears as an echo-free space in between the visceral and parietal layers of the pericardium. Pericardial fat has a similar appearance on echocardiography and it may be difficult to discern the two entities. We present a case of a post-MI patient demonstrating pseudo tamponade physiology in the setting of excessive pericardial fat.

Relation of epicardial adipose tissue to coronary atherosclerosis

Adipose tissue surrounding the coronary arteries has been suggested to induce development of atherosclerosis. We explored the relation between epicardial adipose tissue (EAT) volume and coronary atherosclerosis using multislice computed tomography. The study population consisted of 190 patients who had undergone multislice computed tomographic coronary angiography. Coronary artery calcium score was assessed. In addition, patients were classified as having (1) no atherosclerosis, (2) nonobstructive atherosclerosis (luminal narrowing <50%), (3) obstructive atherosclerosis (luminal narrowing >or=50%) in a single vessel, or (4) obstructive atherosclerosis in the left main coronary artery and/or multiple vessels. Cross-sectional tomographic cardiac slices (3.00-mm thickness, range 35 to 40 slices per heart) were traced semiautomatically from the border of EAT below the apex to a point at the center of the left atrium. Tissue with values from -250 to -30 HU was assigned as EAT. EAT volume within the traced area was then automatically quantified. Mean EAT volume was 84 +/- 41 ml. Patients with a coronary artery calcium score >10 had significantly larger average EAT volume (100 +/- 40 ml) compared with patients with calcium scores <or=10 (59 +/- 27 ml, p <0.001). Sensitivity and specificity for prediction of a calcium score >10 were 77% and 70% with a cut-off EAT value of 73 ml. In patients with normal coronaries mean EAT volume (63 +/- 31 ml) was significantly smaller than in patients with atherosclerosis (99 +/- 40 ml, p <0.001). Using a cut-off EAT volume of 75 ml, the sensitivity and specificity for presence of atherosclerosis were 72% and 70%. Interestingly, quantity of EAT did not significantly increase with increasing extent or severity of atherosclerosis. After adjustments for risk factors EAT volume remained a significant predictor of coronary atherosclerosis (p = 0.001). In conclusion, a significant relation was shown between EAT volume and presence of coronary atherosclerosis. Quantification of EAT may be useful to identify patients at risk for coronary artery disease.

Thinking outside the abdominal box: safe use of the epipericardial fat pad window for percutaneous radiofrequency ablation of hepatic dome tumors

Percutaneous imaging-guided tumor ablation is being increasingly performed for local disease control in a variety of primary and secondary neoplasms. Herein, the authors detail their experience with four patients in whom the epipericardial fat pad was traversed to access tumors within the hepatic dome for radiofrequency ablation. The procedure was technically successful in all patients, and the use of this novel window helped avoid crossing the pleura.