Imaging the pericardium: appearances on ECG-gated 64-detector row cardiac computed tomography

Abstract

Multidetector row computed tomography (MDCT) with its high spatial and temporal resolution has now become an established and complementary method for cardiac imaging. It can now be used reliably to exclude significant coronary artery disease and delineate complex coronary artery anomalies, and has become a valuable problem-solving tool. Our experience with MDCT imaging suggests that it is clinically useful for imaging the pericardium. It is important to be aware of the normal anatomy of the pericardium and not mistake normal variations for pathology. The pericardial recesses are visible in up to 44% of non-electrocardiogram (ECG)-gated MDCT images. Abnormalities of the pericardium can now be identified with increasing certainty on 64-detector row CT; they may be the key to diagnosis and therefore must not be overlooked. This educational review of the pericardium will cover different imaging techniques, with a significant emphasis on MDCT. We have a large research and clinical experience of ECG-gated cardiac CT and will demonstrate examples of pericardial recesses, their variations and a wide variety of pericardial abnormalities and systemic conditions affecting the pericardium. We give a brief relevant background of the conditions and reinforce the key imaging features. We aim to provide a pictorial demonstration of the wide variety of abnormalities of the pericardium and the pitfalls in the diagnosis of pericardial disease.

Figure 1

Line drawing illustrating the relative positions of the transverse and oblique sinuses; the majority of the pericardial recesses take their origin from these spaces. Note the pericardial reflection between the two spaces. The pulmonic venous recesses are also illustrated.

Figure 2

(a) The anterior extension of the superior aortic recess. (b) A coronal reformation demonstrating the right paratracheal position of a high-riding superior pericardial recess. (c) The posterior extension of the superior aortic recess. (d) The left pulmonic recess.

Figure 3

Pericardial effusion. Here, there has been a rapid accumulation of pericardial fluid, particularly on the left side, which is compressing the cardiac chambers and creating a tamponade.

Figure 4

(a) This patient sustained a previously unsuspected iatrogenic left ventricular injury during a mitral valve annuloplasty, and presented with cardiac tamponade secondary to a rapidly accumulating haemorrhagic pericardial effusion. (b) The inferior left ventricle wall has ruptured secondary to acute myocardial infarction causing a haemopericardium and cardiovascular compromise. Note the contrast extravasation and the subendocardial myocardial perfusion defect.

Figure 5

Anterosuperior pericardial thickening and fatty inflammatory change is seen in this patient who presented with acute chest pain and no clinical evidence of myocardial infarction. The patient had pericarditis.

Figure 6

(a) Axial sections through the heart in a four-chamber view in a young Asian male patient with constrictive non-calcified tuberculous pericarditis (see later). The image demonstrates diffuse pericardial thickening, small-volume pericardial effusion, a flattened interventricular septum and a small right pleural effusion. (b) Axial sections through the upper abdomen in the same patient, showing ascites, hepatomegaly and dilatation of the hepatic inferior vena cava and hepatic veins with reflux of intravenous contrast.

Figure 7

Volume-rendered MDCT (c, d) demonstrates in three dimensions florid, irregular, amorphous, pericardial calcified plaques causing constrictive pericardial disease. Areas of non-calcified pericardial thickening can also be appreciated in the four-chamber (c, d) and two-chamber planes (a, b) above. In this case, CT aided in surgical resection.

Figure 8

Non-gated contrast-enhanced chest CT image in the axial plane. At the right cardiophrenic angle there is an ovoid structure with attenuation value in keeping with fluid density that does not enhance with contrast. The structure proved to be a pericardial cyst, following aspiration.

Figure 9

Gated contrast-enhanced axial image.This patient has undergone aortic valve replacement and grafts. There is mediastinal fibrosis (black arrow) (seen as thickened soft tissue anterior to the right ventricle and just posterior to the sternum), which could be mistaken for a thickened pericardium when the pericardium is in fact absent. The right heart is enlarged and the septum is bowed (white arrow), which are also findings in constrictive pericarditis.

Figure 10

Non-gated contrast-enhanced chest CT axial image. This patient was known to have breast cancer and had undergone radiotherapy; the lung demonstrates a linear area of fibrosis consistent with this. On further imaging the pericardium has become nodular and thickened (black arrow) and enhances with contrast. There are also lung (white arrowhead) and liver deposits consistent with metastatic disease; however, without a biopsy it is impossible to tell whether the pericardial change is secondary to metastatic spread or radiation.

Figure 11

An axial section through the heart in a patient with end-stage lung cancer demonstrates a soft tissue mass infiltrating the pericardium and myocardium on the left poterolateral wall. A small volume of ascites can also be seen around the spleen.

Figure 12

(a) ECG-gated contrast-enhanced cardiac CT images demonstrate a large, heterogeneously enhancing, pericardial mass on the antero-inferior border of the heart causing right heart compression and elevated right heart pressure. The patient initially presented with right heart failure. The tumour was entirely resected and proved to be a sarcoma on histology. (b) the same patient CT in the axial plane.

Figure 13

In the context of a patient presenting with acute chest pain radiating to the back, CT angiography of the aorta demonstrates a volume of fluid within normal limits within the posterior extension of the superior pericardial recess mistaken for ascending aortic intramural haematoma. Note the crescent-shaped fluid density immediately posterior to the aorta, which on multiplanar reformatting was found to be continuous with the pericardial cavity.

Figure 14

This patient with a history of thyroid malignancy underwent CT which demonstrated a well-defined fluid density within an atypical high-riding superior aortic recess. This was initially misdiagnosed as an enlarged lymph node and subsequently found at surgery to be a pericardial recess.