CT of the pericardial recesses

Abstract

sinus. An understanding of sectional anatomy is valuable for differentiation of fluid within these recesses from mediastinal masses or enlarged lymph nodes on computed tomographic scans.The pencardium consists of an outer fibrous envelope and an inner serous sac, which is invaginated by the heart [1]. The serous pericardium can be divided into a visceral layer, or epicardium, which covers the heart and great vessels, and a panetal layer, which lines the fibrous pericardium[1]. The visceral pericardium is reflected from the heart, along the great vessels, and onto the parietal pericardium. At these reflections and between the great vessels, recesses or sinuses are formed within the pericardial space [1-3]. These include the superior pencardial recess, transverse and oblique sinuses, the left pulmonic recess, the pulmonary venous recesses, and the recesses around the superior and inferior venae cavae. Clinically detectable fluid between the visceral and panetal layers of the pencardium is generally located anterior to the ventrides, behind the left ventricular midposterior free wall, or inferior to the heart [4-1 2] ( fig. 1). However, fluid also may accumulate within the peicardial recesses ( fig. 2), where it may be mistaken on computed tomography (CT) for pathologic changes in adjacent structures, such as the thymus, esophagus, bronchi, hila, and mediastinal lymph nodes. This report illustrates the anatomy of the pericardial recesses with cadaver sections and in vivo CT scans. The frequency with which these recesses may contain pericardial fluid is estimated on the basis of a study of 27 consecutive CT examinations of patients with pericardial effusion. Materials and MethodsTwo supine cadavers were injected intrapericardially with 1% water-soluble contrast medium, using a 22-gauge needle under CT gu ance.The thin needle was initially placed into the right ventricle from a left parastemal location. It was then withdrawn gradually until the anterior pencardial space could be opacifled. Consecutive CT scans through the heart and mediastinum were then Obtained at 10-mm intervals, using 10-mm collimation. Anatomic transverse sections from one of the cadavers are illustrated in figure 3.Twenty-seven consecutive CT scans from 24 patients with pericardial effusions were revlewed. There were 13 female and 1 1 male patients aged 5-81 years (medIan, 60). Three patients had two CT scans each, separated by intervals of 3-28 weeks. The pencardial fluid was associated with neoplasia in 16 patients, heart failure in four patients, and pericarditis due to infection or vasculitis in three patients. The remaining patient had a hemopericardium Downloaded from www.ajronline.org by 54.149.104.195 on 05/10/18 from IP address 54.149.104.195.

Magnetic resonance imaging of the superior pericardial recesses

“…In our series, the retroaortic recess was shown on only one of four CT scans but on at least 67% of transverse MR scans. The preaortic recess has also been demonstrated on CT scans [2,8] and was seen on 20% of CT scans of patients without pericardial effusion [2]. In our series, none of the four subjects who had undergone CT had a CT scan that demonstrated the preaortic recess, but 82% of the nongated the visibility of this recess on CT scans.…”

“…On CT scans, the retroaortic recess has been mistaken for adenopathy [1], and the preaortic recess could be confused with thymic enlargement or anterior mediastinal adenopathy [2], but the low signal intensity of these recesses on MRI permits their differentiation from the slightly higher signal intensity of lymph nodes or thymus.…”

MR imaging of the transverse sinus of the pericardium

“…The CT appearance of the transverse sinus has recently been described in patients with pericardial effusions [5]. On MR of subjects without pericardial disease, we have noticed a low-signal-intensity structure in this location, which can mimic an anomalous vessel, left coronary artery, aortic dissection, or enlarged mediastinal lymph nodes.…”

“…Continuity of the retroaortic segment with the superior pericardial recess and its visualization at a site only 1 -2 cm to the right of the mid-sagittal plane help in its identification. The retropulmonary segment usually appears as a thin, curvilinear structure adjacent to the posterior wall of the right pulmonary artery [4,5,8]. However, it can appear on MR as a thick band that may mimic a subcarinal lymph node (Fig.…”

Evaluation of pericardial sinuses and recesses with 2-, 4-, 16-, and 64-row multidetector CT

“…However, many of these researchers used thick-section CT and described only some of the recesses. A few reports describe the appearance of all pericardial sinuses and recesses on CT [6][7][8]. Multidetector technology has improved anatomical imaging by providing rapid acquisition of volumetric data with thinner sections and the ability to generate multiplanar reformats.…”