الفهرس 
ABSTRACTOnly 14 pages are availabe for public view
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Abstract
Pericardial disease is an important cause of morbidity and mortality in patients with cardiovascular disease. Although the pericardium is usually sufficiently thick to be identified on CCT and CMR, visualization at the most common site of pericardial defects, the lateral, posterior, and inferior left ventricular wall, can be poor because of a paucity of fat.
Trans-thoracic echocardiography (TTE) should be the first modality to determine the hemodynamic significance of a pericardial effusion. Both CCT and CMR imaging are useful adjuncts to TTE in the characterization of a pericardial effusion and tamponade. They both play an important role in situations in which the hemodynamics are atypical and the presence and severity of tamponade are less certain. Both CCT and CMR provide more detailed quantification and localization of the effusion than TTE, and they are especially useful to guide pericardiocentesis, since loculated or regional effusions or regions of calcified pericardium can be identified. When hemopericardium complicates aortic dissection, CCT and CMR can readily identify the 2 diagnoses, thereby preventing inappropriate and potentially catastrophic pericardiocentesis. Loculated effusions, especially those in anterior locations, can be difficult to detect at echocardiography but are readily demonstrated at CT or MR imaging, both of which provide a wider field of view. CT attenuation measurements also enable the initial characterization of pericardial fluid.
A CCT scan is able to detect even minute amounts of calcification, a finding highly suggestive of constrictive pericarditis. Other findings of constrictive pericarditis on CCT include a pericardial thickness of >4 mm (diffuse or localized), narrowing and tubular deformation of the RV, and straightening of the IVS. Additional secondary findings include signs of impaired diastolic filling of the RV: dilatation of the IVC, hepatic veins, and RA, as well as hepatosplenomegaly, ascites, and pleural effusions. In patients being considered for pericardiectomy, detailed descriptions of the location and severity of thickening and calcification will aid the surgeon with respect to both risk stratification and planning of the procedure.
Because the pericardium is outlined by fat and lung tissue, an accurate measurement of pericardial thickness using CMR is clinically feasible with a reported accuracy of 93% when the pericardium is >4 mm thick. Calcification may not be visualized very well on CMR, and therefore CCT may be more useful for this purpose. Spin echo sequences are useful to detect thickened pericardium, whereas focal pericardial thickening and pericardial effusions are better visualized using cine gradient echo images sensitive to pericardial fluid. Additional CMR findings of constrictive pericarditis are similar to those for CCT. Abnormal diastolic septal motion on CMR yields a sensitivity of 81% and a specificity of 100% for the diagnosis of constrictive pericarditis.
Most benign neoplasms are curable with surgery, and therefore radiologic detection and characterization is critical. The early diagnosis of malignant neoplasms plays a role in palliation. In cases of lymphoma, chemotherapy may result in remission of disease. Chest radiographs are frequently abnormal, reflecting the location and extent of tumor and prompting further investigation. CT & CMR are generally necessary to accurately delineate the tumor implantation and to better evaluate the extent of tumor spread. Disruption of the pericardial lining, presence of an associated hemorrhagic effusion, and invasion of the tumor into the epicardial fat tissue, myocardium, or into a cardiac chamber (rather than causing displacement of these structures) are characteristics of a lesion with an aggressive nature. Associated lymphadenopathy is another important finding suggesting malignancy. Tissue characterization with CMR is superior to cardiac CT and echocardiography. CMR can differentiate tumor from thrombus and is often helpful to assess the perfusion of a pericardial mass with the use of gadolinium contrast. The final diagnosis depends on typical pathologic features.
Clinicians increasingly rely on cardiac imaging in the diagnostic workup of patients with pericardial disease. Continuous advances in cardiac CT and CMR technology allow for an excellent visualization and characterization of pericardial pathology, making these tomographic techniques more than adjuncts to echocardiography. An integrated multimodality imaging strategy is sometimes needed to answer specific clinical questions, but the rational use of such an approach also requires good knowledge of the strengths and limitations of each technique. Given the paucity of evidence-based guidelines, more clinical studies are needed to better define the role of cardiac imaging in the management of patients with pericardial disease.