Pericardial ???Sleeve??? Recess of Right Inferior Pulmonary Vein Mimicking Adenopathy

Pericardial Recesses on Computed Tomography: Implications for the Pulmonologist

The pericardium comprises a double-walled fibrous-serosal sac that encloses the heart. Reflections of the serosal layer form sinuses and recesses. With advances in multidetector computed tomography (CT) technology, pericardial recesses are frequently detected with thin-section CT. Knowledge of pericardial anatomy on imaging is crucial to avoid misinterpretation of fluid-filled pericardial sinuses and recesses as adenopathy/pericardial metastasis or aortic dissection, which can impact patient management and treatment decisions. The authors offer a comprehensive review of pericardial anatomy and its variations observed on CT, potential pitfalls in image interpretation, and implications for the pulmonologist with respect to unnecessary diagnostic procedures or interventions.

Pitfalls in Oncologic Imaging of the Pericardium on CT and PET/CT

In the oncologic setting, misinterpretation of fluid in pericardial recesses as mediastinal adenopathy or benign pericardial findings as malignant can lead to inaccurate staging and inappropriate management. Knowledge of normal pericardial anatomy, imaging features to differentiate fluid in pericardial sinuses and recesses from mediastinal adenopathy and potential pitfalls in imaging of the pericardium on CT and PET/CT is important to avoid misinterpretation.

Pericardial Recesses Mimicking Mediastinal Adenopathy on CT

Thin-section computed tomography (CT) has improved the detection of pericardial recesses and sinuses. Physiologic fluid in the pericardial recesses and sinuses can mimic mediastinal adenopathy. The misinterpretation of pericardial recesses and other benign pericardial entities in the oncologic setting can lead to inappropriate staging and management. Knowledge of the anatomy of the pericardium with emphasis on the imaging of different pericardial recesses on CT is important to avoid misdiagnosis, unnecessary further investigations, and/or biopsy.

Imaging of the mediastinum: Mimics of malignancy

In the imaging of the mediastinum, benign lesions mimicking malignancy constitute potential pitfalls in interpretation. Localization and characteristic imaging features are key to narrow the differential diagnosis and avoid potential pitfalls in interpretation. Based on certain anatomic landmarks, the mediastinal compartment model enables accurate localization. Depending on the anatomic origin, mediastinal lesions can have various etiologies. The anatomic location and structures contained within each mediastinal compartment are helpful in generating the differential diagnoses. These structures include thyroid, thymus, parathyroid, lymph nodes, pericardium, embryogenic remnants, and parts of the enteric tracts, vessels, and nerves. Imaging characteristics on computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET/CT), including attenuation (fluid, fat, calcification), contrast enhancement, and metabolic activity, aid in narrowing the differential diagnoses. Understanding the roles and limitations of various imaging modalities is helpful in the evaluation of mediastinal masses. In this review, we present potential pitfalls in the imaging of mediastinal lesions with emphasis on the mimics of malignancy.

Imaging of Pericardial Disease

Although the pericardium is simply a 2-layered membrane enveloping the heart and great vessels, there are numerous anatomic variations, congenital anomalies, and pathologic conditions that can occur. Although echocardiography is most often the first imaging modality used to assess the pericardium, computed tomography and MR imaging are frequently being used to aid in diagnosis and assess response to therapy. Therefore, detailed knowledge of the pericardium in both its normal and diseased states is important to best direct patient care and potentially improve patient outcomes.

Differentiating pericardial recesses from mediastinal adenopathy: potential pitfalls in oncological imaging

In oncological imaging, staging with computed tomography (CT) is widely used to determine treatment. Misinterpretation of fluid in pericardial recesses as mediastinal adenopathy can lead to inaccurate clinical staging and inappropriate management. In this review, we describe normal pericardial anatomy and illustrate imaging features to differentiate fluid in pericardial sinuses and recesses from mediastinal adenopathy.

Learning from the pulmonary veins

The purpose of this article is to review the basic embryology and anatomy of the pulmonary veins and the various imaging techniques used to evaluate the pulmonary veins, as well as the radiologic findings in diseases affecting these structures. Specific cases highlight the clinical importance of the imaging features, particularly the findings obtained with multidetector computed tomography (CT). Pulmonary vein disease can be broadly classified into congenital or acquired conditions. Congenital disease, which often goes unnoticed until patients are adults, mainly includes (a) anomalies in the number or diameter of the vessels and (b) abnormal drainage or connection with the pulmonary arterial tree. Acquired disease can be grouped into (a) stenosis and obstruction, (b) hypertension, (c) thrombosis, (d) calcifications, and (e) collateral circulation. Pulmonary vein stenosis or obstruction, which often has important clinical repercussions, is frequently a result of radiofrequency ablation complications, neoplastic infiltration, or fibrosing mediastinitis. The most common cause of pulmonary venous hypertension is chronic left ventricular failure. This condition is difficult to differentiate from veno-occlusive pulmonary disease, which requires a completely different treatment. Pulmonary vein thrombosis is a rare, potentially severe condition that can have a local or distant cause. Calcifications have been described in rheumatic mitral valve disease and chronic renal failure. Finally, the pulmonary veins can act as conduits for collateral circulation in cases of obstruction of the superior vena cava. Multidetector CT is an excellent modality for imaging evaluation of the pulmonary veins, even when the examination is not specifically tailored for their assessment.

Extracardiac Findings at Cardiac CT

Noncardiac findings occur in 10% to 60% of cases depending on the patient population studied. Although most of the abnormalities will turn out to be benign, important findings such as pulmonary embolism and lung cancer occur. Not all important abnormalities will occur within the coned down field-of-view for evaluating the coronary arteries, and the entire study should also be reviewed with an expanded field-of-view. In particular, the typical screen detected cancer occurs in the lung periphery. It is important to have a practical approach in detecting and evaluating incidental findings so as not to cause undue cost or patient anxiety, while ensuring timely management of critical diseases.