Portal de Periódicos da CAPES

American Society of Echocardiography Clinical Recommendations for Multimodality Cardiovascular Imaging of Patients with Pericardial Disease

2013; Elsevier BV; Volume: 26; Issue: 9 Linguagem: Inglês

10.1016/j.echo.2013.06.023

1097-6795

Allan L. Klein, Suhny Abbara, Deborah A. Agler, Christopher P. Appleton, Craig R. Asher, Brian D. Hoit, Judy Hung, Mario J. García, Itzhak Kronzon, Jae K. Oh, E. René Rodríguez, Hartzell V. Schaff, Paul Schoenhagen, Carmela D. Tan, Richard D. White,

Cardiac Imaging and Diagnostics

Attention ASE Members:The ASE has gone green! Visit www.aseuniversity.org to earn free continuing medical education credit through an online activity related to this article. Certificates are available for immediate access upon successful completion of the activity. Nonmembers will need to join the ASE to access this great member benefit! The ASE has gone green! Visit www.aseuniversity.org to earn free continuing medical education credit through an online activity related to this article. Certificates are available for immediate access upon successful completion of the activity. Nonmembers will need to join the ASE to access this great member benefit! The writing committee was made up of experts in pericardial diseases and imaging of the pericardium from the American Society of Echocardiography (ASE), the Society for Cardiovascular Magnetic Resonance Imaging, and the Society of Cardiovascular Computed Tomography. The document was reviewed by the ASE Guidelines and Standards Committee and official reviewers nominated by the Society for Cardiovascular Magnetic Resonance Imaging and the Society of Cardiovascular Computed Tomography. The objective of this document is to provide a consensus expert opinion on the appropriate use of multimodality imaging in the diagnosis and management of pericardial diseases. This document will allow clinicians to weigh the evidence on the strengths and weaknesses of a particular imaging modality in the evaluation and management of pericardial diseases. Of note, there have been only a small number of randomized clinical trials on pericardial diseases1Imazio M. Bobbio M. Cecchi E. Demarie D. Demichelis B. Pomari F. et al.Colchicine in addition to conventional therapy for acute pericarditis: results of the Colchicine for Acute Pericarditis (COPE) trial.Circulation. 2005; 112: 2012-2016Crossref PubMed Scopus (169) Google Scholar, 2Imazio M. Brucato A. Cemin R. Ferrua S. Belli R. Maestroni S. et al.Colchicine for Recurrent Pericarditis (CORP): a randomized trial.Ann Intern Med. 2011; 155: 409-414Crossref PubMed Google Scholar, 3Imazio M. Trinchero R. Brucato A. Rovere M.E. Gandino A. Cemin R. et al.Colchicine for the Prevention of the Post-Pericardiotomy Syndrome (COPPS): a multicentre, randomized, double-blind, placebo-controlled trial.Eur Heart J. 2010; 31: 2749-2754Crossref PubMed Scopus (50) Google Scholar; thus, we use a consensus of expert opinions in this report and do not attempt to use the standard level-of-evidence grading system (Levels A-C). The document focuses on multimodality imaging of pericardial diseases, including echocardiography, computed tomography (CT), and cardiovascular magnetic resonance (CMR), and is not comprehensive with regard to clinical presentation and treatment, which have been discussed in recent reviews.4Imazio M. Spodick D.H. Brucato A. Trinchero R. Adler Y. Controversial issues in the management of pericardial diseases.Circulation. 2010; 121: 916-928Crossref PubMed Scopus (66) Google Scholar, 5Khandaker M.H. Espinosa R.E. Nishimura R.A. Sinak L.J. Hayes S.N. Melduni R.M. et al.Pericardial disease: diagnosis and management.Mayo Clin Proc. 2010; 85: 572-593Abstract Full Text Full Text PDF PubMed Scopus (65) Google Scholar Pericardial diseases are very common worldwide, encountered in various settings (including primary care, emergency room, and subspecialty settings such as rheumatology, infectious diseases, oncology, and cardiology), and can have significant morbidity as well as mortality.5Khandaker M.H. Espinosa R.E. Nishimura R.A. Sinak L.J. Hayes S.N. Melduni R.M. et al.Pericardial disease: diagnosis and management.Mayo Clin Proc. 2010; 85: 572-593Abstract Full Text Full Text PDF PubMed Scopus (65) Google Scholar, 6Troughton R.W. Asher C.R. Klein A.L. Pericarditis.Lancet. 2004; 363: 717-727Abstract Full Text Full Text PDF PubMed Scopus (215) Google Scholar Patients can present with variable symptoms of chest pain, shortness of breath, ascites, leg swelling, and hypotension. Pericardial diseases can be grouped into a constellation of clinical syndromes, including acute pericarditis, recurrent pericarditis, pericardial effusion (PEff) or tamponade, constrictive pericarditis (CP), pericardial masses, and congenital anomalies of the pericardium. The etiologic classification of pericardial diseases includes infectious, autoimmune, post-myocardial infarction, and autoreactive causes, as reported in the European pericardial guidelines.7Maisch B. Seferovic P.M. Ristic A.D. Erbel R. Rienmuller R. Adler Y. et al.Guidelines on the diagnosis and management of pericardial diseases executive summary; the Task Force on the Diagnosis and Management of Pericardial Diseases of the European Society of Cardiology.Eur Heart J. 2004; 25: 587-610Crossref PubMed Scopus (570) Google Scholar In a substantial subset of patients, etiology is not apparent and is classified as idiopathic. However, the diagnosis as well as the management of pericardial diseases can be complex, with such conditions as mixed CP with myocardial and/or valvular heart disease, transient CP, effusive CP, or localized postoperative tamponade.8Verhaert D. Gabriel R.S. Johnston D. Lytle B.W. Desai M.Y. Klein A.L. The role of multimodality imaging in the management of pericardial disease.Circ Cardiovasc Imaging. 2010; 3: 333-343Crossref PubMed Scopus (41) Google Scholar Clearly, the evaluation of these pericardial conditions can be difficult to detect clinically; therefore, there is an increasing role for the use of imaging techniques including echocardiography, CMR, and CT,9Yared K. Baggish A.L. Picard M.H. Hoffmann U. Hung J. Multimodality imaging of pericardial diseases.JACC Cardiovasc Imaging. 2010; 3: 650-660Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar, 10Bogaert J. Francone M. Pericardial disease: value of CT and MR imaging.Radiology. 2013; 267: 340-356Crossref PubMed Scopus (11) Google Scholar in the diagnosis and management of these conditions. Multimodality imaging is an integral part of modern management for most, if not all, cardiovascular conditions, including pericardial diseases. Although imaging is often performed to confirm an initial clinical suspicion, it sometimes provides a clinically unsuspected diagnosis as well as a complementary approach to the clinical assessment. Therefore, imaging should follow a careful history and physical examination, electrocardiography (ECG), and chest x-ray and then be focused toward the clinical working diagnosis. This stepwise approach is important to avoid unnecessary testing with its potential risk for side effects, false-positive diagnoses, and inappropriate allocation of resources, thus avoiding excessive costs. Among multimodality imaging tests, echocardiography is most often the first-line test, followed by CMR11American College of Cardiology Foundation Task Force on Expert Consensus Documents Hundley W.G. Bluemke D.A. Finn J.P. Flamm S.D. Fogel M.A. et al.ACCF/ACR/AHA/NASCI/SCMR 2010 expert consensus document on cardiovascular magnetic resonance: a report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents.J Am Coll Cardiol. 2010; 55: 2614-2662Abstract Full Text Full Text PDF PubMed Scopus (141) Google Scholar and/or CT.12Hendel R.C. Patel M.R. Kramer C.M. Poon M. Hendel R.C. Carr J.C. et al.ACCF/ACR/SCCT/SCMR/ASNC/NASCI/SCAI/SIR 2006 appropriateness criteria for cardiac computed tomography and cardiac magnetic resonance imaging: a report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group, American College of Radiology, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, American Society of Nuclear Cardiology, North American Society for Cardiac Imaging, Society for Cardiovascular Angiography and Interventions, and Society of Interventional Radiology.J Am Coll Cardiol. 2006; 48: 1475-1497Abstract Full Text Full Text PDF PubMed Scopus (788) Google Scholar, 13Taylor A.J. Cerqueira M. Hodgson J.M. Mark D. Min J. O'Gara P. et al.ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.J Cardiovasc Comput Tomogr. 2010; 4: 407.e1-407.e33Abstract Full Text Full Text PDF Scopus (0) Google Scholar Each of the tests can be useful in the evaluation of the structure and hemodynamic and/or functional disturbances of pericardial diseases. For example, echocardiography with respirometric recording would be considered the first-line modality to evaluate the anatomic and physiologic features of CP. CMR and CT would be second-line tests to further assess the degree of increased pericardial thickness, functional effects of the constrictive process, inflammation, as well as the distribution of calcium in the pericardium.8Verhaert D. Gabriel R.S. Johnston D. Lytle B.W. Desai M.Y. Klein A.L. The role of multimodality imaging in the management of pericardial disease.Circ Cardiovasc Imaging. 2010; 3: 333-343Crossref PubMed Scopus (41) Google Scholar It is important to note that all three tests are rarely necessary in the diagnosis of CP unless there are technically poor or diagnostically uncertain transthoracic echocardiographic studies, there is mixed CP and restriction, being evaluated for pericardiectomy, or there is a concern for transient constriction with ongoing inflammation, as an example. Sometimes, an invasive hemodynamic study is necessary to evaluate myocardial versus pericardial diastolic heart failure, especially in the setting of atrial fibrillation. The strengths and weaknesses of each modality are shown in Table 1.8Verhaert D. Gabriel R.S. Johnston D. Lytle B.W. Desai M.Y. Klein A.L. The role of multimodality imaging in the management of pericardial disease.Circ Cardiovasc Imaging. 2010; 3: 333-343Crossref PubMed Scopus (41) Google Scholar A description of the pericardial disease-specific protocol for each modality is shown in Table 2 and the Appendix (available at www.onlinejase.com). Echocardiography remains as an initial imaging test in most scenarios because of its ease of use, wide availability, bedside availability, cost-effectiveness, and comprehensive assessment of both anatomy and physiology. After review of the results of transthoracic echocardiography (TTE) and integration with other available data, such as the clinical examination and ECG, additional imaging is often not necessary in many patients. However, the use of additional imaging modalities should be justified by the expected incremental information complementary to the physiologic and structural information obtained from TTE.Table 1Comparison of multimodality imaging modalities in the evaluation of pericardial diseasesAdapted with permission from Verhaert.8Verhaert D. Gabriel R.S. Johnston D. Lytle B.W. Desai M.Y. Klein A.L. The role of multimodality imaging in the management of pericardial disease.Circ Cardiovasc Imaging. 2010; 3: 333-343Crossref PubMed Scopus (41) Google ScholarEchocardiographyCTCMRMain strengths•First-line imaging test in the diagnostic evaluation of pericardial disease•Readily available•Low cost•Safe•Can be performed at bedside or urgent situations•Portable•TEE available for better evaluation•High frame rate•Can be performed with respirometer•Second-line for better anatomic delineation•Evaluation of associated/extracardiac disease•Preoperative planning•Evaluation of pericardial calcification•Second-line for better anatomic delineation•Superior tissue characterization•Evaluation of inflammationMain weaknesses•Limited windows, narrow field of view•Technically limited with obesity, COPD, or postoperative setting•Relatively operator dependent•Low signal-to-noise ratio of the pericardium•Limited tissue characterization•Use of ionizing radiation•Use of iodinated contrast•Functional evaluation only possible with retrospective gated studies (higher radiation dose, suboptimal temporal resolution)•Difficulties in case of tachycardia or unstable heart rhythm (particularly for prospective gated studies)•Need for breath-hold•Hemodynamically stable patients only•Time-consuming, high cost•Preferably stable heart rhythms•Relatively contraindicated in case of pacemaker or ICD•Lung tissue less well visualized•Calcifications not well seen•Use of gadolinium contrast contraindicated in case of advanced renal dysfunction (glomerular filtration rate <30 mL/min)•Use of some breath-hold sequences•Hemodynamically stable patients onlyCOPD, Chronic obstructive pulmonary disease; ICD, implantable cardioverter-defibrillator. Open table in a new tab Table 2Protocols and findings for the multimodality imaging modalities in the evaluation of pericardial diseases (see Appendix)Adapted with permission from Verhaert.8Verhaert D. Gabriel R.S. Johnston D. Lytle B.W. Desai M.Y. Klein A.L. The role of multimodality imaging in the management of pericardial disease.Circ Cardiovasc Imaging. 2010; 3: 333-343Crossref PubMed Scopus (41) Google ScholarEchocardiographyProspective or retrospective electrocardiographically gated multidetector CTCMR2D echocardiography•PEff (size, location, free flowing vs organizing, suitability for pericardiocentesis vs window)•Pericardial thickness (particularly TEE)•Collapse of right-sided chambers (duration of diastole and relation with respiration)•Early diastolic septal bounce, respiratory shift of the ventricular septum•IVC plethora•Pleural effusion/ascites•RA tethering (best seen by TEE)•Stasis of agitated saline contrast in right atrium (sluggish flow)Axial imaging•Pericardial calcification and thickening•Localization and characterization of PEffs, cysts, or masses•Evaluation of lungs (pleural effusion, postradiation fibrosis, malignancy), and liver (cirrhosis, ascites)•Proximity of bypass grafts and/or other vital structures to the sternum (preoperative planning)Bright-blood single-shot SSFP and black-blood axial stacks∗Orientation: axial. (half Fourier SSTSE, electrocardiographically gated)•Presence of pleural effusion, ascites, distension of the IVC, assessment of pericardial thickeningDoppler + simultaneous respirometry†Doppler measurements should be repeated in the sitting position (reducing preload) in case of nondiagnostic findings and suspicion for constriction to lower the preload.•Restrictive mitral inflow pattern•Reciprocal respiratory changes of mitral (and tricuspid) inflow•Reciprocal respiratory changes of diastolic forward flow velocity and end-diastolic flow reversal in hepatic veins•Tissue Doppler velocities of mitral annulus, color Doppler M-mode of mitral inflow•2D strain of longitudinal and circumferential deformationMultiplanar reconstruction•Chamber dimensions (RA enlargement, conical ventricular deformity)•Assess coronary patencyBlack-blood images‡Orientation: two-chamber, three-chamber, and four-chamber views plus three short-axis LV slices (basal, mid, and distal). (T1W + T2W fast SE); optional: T2W STIR (edema-weighted) fast SE•Tissue characterization, measurement of pericardial thickness•Assessment of pericardial inflammation and masses (STIR sequence)M-mode•Flattening of the posterior wall during diastole•Respiratory variation of ventricular sizeVolume-rendered imaging•Extent and distribution of pericardial calcificationTagged cine images§Orientation: three short-axis LV slices (basal, mid, and distal); optional: two-chamber, three-chamber, and four-chamber views. (T1W gradient-echo)•Epicardial/pericardial tetheringCine imaging (retrospectively gated study only)•Functional evaluation (septal bounce, pericardial tethering)Bright-blood cine imagesOrientation: two-chamber, three-chamber, and four-chamber views plus 3 short-axis LV slices. (SSFP)•Atrial/ventricular size and function•Diastolic restraint•Conical deformity of the ventricles•Myocardial tethering•Diastolic septal bounce•Pericardial thickening and/or effusionLGE images¶Orientation: two-chamber, three-chamber, and four-chamber views plus short-axis stack. (phase-sensitive inversion-recovery sequence)•Detection of pericardial inflammationReal-time gradient-echo cine image#Orientation: basal and mid short-axis slice with diaphragm in view.•Monitor respiratory variation of ventricular septal motion and interventricular dependenceSSTSE, Single-shot turbo SE.∗ Orientation: axial.† Doppler measurements should be repeated in the sitting position (reducing preload) in case of nondiagnostic findings and suspicion for constriction to lower the preload.‡ Orientation: two-chamber, three-chamber, and four-chamber views plus three short-axis LV slices (basal, mid, and distal).§ Orientation: three short-axis LV slices (basal, mid, and distal); optional: two-chamber, three-chamber, and four-chamber views.|| Orientation: two-chamber, three-chamber, and four-chamber views plus 3 short-axis LV slices.¶ Orientation: two-chamber, three-chamber, and four-chamber views plus short-axis stack.# Orientation: basal and mid short-axis slice with diaphragm in view. Open table in a new tab COPD, Chronic obstructive pulmonary disease; ICD, implantable cardioverter-defibrillator. SSTSE, Single-shot turbo SE. We acknowledge several limitations of this report. Obviously, the recommendations for the groups of clinical scenarios may not fit individual situations and may therefore require us to deviate from the proposed decision trees. Current published data are limited and based on relatively small, single-center experience, with a lack of large randomized prospective trials. The clinical presentation, diagnostic considerations, and therapeutic interventions for pericardial diseases described in this report would apply only in part to the care of patients in developed countries14Mocumbi A.O. Ferreira M.B. Neglected cardiovascular diseases in Africa: challenges and opportunities.J Am Coll Cardiol. 2010; 55: 680-687Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar and not necessarily developing countries. The pericardium, a roughly flask-shaped sac that contains the heart, consists of a fibrous and a serosal component. The outer fibrous sac is composed primarily of collagen fibers with interspersed short elastic fibrils.15Ishihara T. Ferrans V.J. Jones M. Boyce S.W. Kawanami O. Roberts W.C. Histologic and ultrastructural features of normal human parietal pericardium.Am J Cardiol. 1980; 46: 744-753Abstract Full Text PDF PubMed Scopus (45) Google Scholar The fibrous envelope is continuous with the adventitia of the great vessels superiorly and is attached to the central tendon of the diaphragm inferiorly. It is attached anteriorly to the sternum by sternopericardial ligaments. In the anteroinferior portion, the pericardium may come in direct contact with the costal cartilages of the left fourth to sixth ribs. The lateral surfaces are invested by the mediastinal part of the parietal pleura (Figure 1). Posteriorly, it is related to the major bronchi, esophagus, and descending thoracic aorta. The phrenic nerves and pericardiophrenic vessels are contained in a bundle between the fibrous pericardium and the mediastinal pleura anterior to the pulmonary hilum (Figure 2). The serosal component consists of a single layer of mesothelium that forms a parietal and a visceral layer enclosing the pericardial cavity. The parietal layer lines the fibrous pericardium, and together, these structures form the parietal pericardium (Figures 3A and 3B). The visceral layer is also known as the epicardium and covers the heart (Figures 3C and 3D). Between the visceral pericardium and the myocardium is a variable amount of epicardial adipose tissue (Figure 4). Epicardial fat is most abundant along the atrioventricular and interventricular grooves and over the right ventricle, especially at the acute border. The epicardial fat contains the coronary arteries and veins, lymphatics, and nerve tissue. The parietal pericardium can be visualized as a curvilinear density on CT and low-intensity signal on CMR delineated by epipericardial and epicardial fat (Figure 5, Figure 6, Figure 7). The parietal pericardium exhibits a normal variation in thickness from region to region and is between 0.8 and 1 mm thick as measured in anatomic studies but appears slightly thicker on imaging.16Ferrans V.J. Ishihara T. Roberts W.C. Anatomy of the pericardium.in: Reddy P.S. Leon D.F. Shaver J.A. Pericardial disease. Raven, New York1982: 77-92Google Scholar The thinnest segments of the pericardium ranged from 0.7 to 1.2 mm in width when measured by CT and 1.2 to 1.7 mm on CMR.17Bull R.K. Edwards P.D. Dixon A.K. CT dimensions of the normal pericardium.Br J Radiol. 1998; 71: 923-925Crossref PubMed Google Scholar, 18Sechtem U. Tscholakoff D. Higgins C.B. MRI of the normal pericardium.AJR Am J Roentgenol. 1986; 147: 239-244Crossref PubMed Google Scholar The discrepancy in pericardial thickness may be partially explained by including small amounts of physiologic pericardial fluid in the measured thickness.18Sechtem U. Tscholakoff D. Higgins C.B. MRI of the normal pericardium.AJR Am J Roentgenol. 1986; 147: 239-244Crossref PubMed Google Scholar TTE is unreliable for measuring pericardial thickness; however, TEE has been shown to be reproducible, compared with CT, for pericardial thickness measurements in normal controls and patients with CP.19Ling L.H. Oh J.K. Tei C. Click R.L. Breen J.F. Seward J.B. et al.Pericardial thickness measured with transesophageal echocardiography: feasibility and potential clinical usefulness.J Am Coll Cardiol. 1997; 29: 1317-1323Abstract Full Text Full Text PDF PubMed Scopus (61) Google ScholarFigure 3(A) Normal, full-thickness parietal pericardium is shown. It consists of a layer of mesothelial cells and compact layers of dense wavy collagen (yellow) with interspersed short elastic fibers (black). (B) Fibroblasts with elongated nuclei and scant thin blood vessels are normally present in the parietal pericardium. CD34 immunostaining highlights the endothelial cells of capillaries. (C) The visceral pericardium (also called epicardium) consists of a mesothelial cell layer and a thin subepithelial layer of collagen with elastic fibers. The mesothelial cells show distinct microvilli. Beneath the visceral pericardium is epicardial adipose tissue. (D) In other areas of the visceral pericardium (or epicardium), only a thin layer of fibrous tissue (yellow) separates the mesothelial cells from the myocardium with absence of epicardial fat. Original magnifications 400×; A, C, and D: Movat pentachrome stain; B: CD34 immunoperoxidase.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 4(A) Coronal section of the heart showing that the epicardial fat is abundant in the right atrioventricular sulcus where a cross-section of the right coronary artery is seen (arrow). The RV free wall also contains a variable amount of epicardial fat that helps outline the pericardium. Note the abundance of epipericardial fat at the angle between the pericardium and diaphragm anteriorly. (B) The parietal pericardium is well delineated by the epipericardial fat on the anterior diaphragmatic surface and epicardial fat over the right ventricle. (C) The left ventricle contains little epicardial fat, resulting in poor visualization of the pericardium in this area on imaging.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 5Contrast-enhanced computed tomographic nongated axial image showing the pericardium anterior to the right ventricle (yellow arrow), surrounded by layers of epicardial (red arrow) and pericardial fat.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 6SSFP gradient-echo white blood cine images in modified four-chamber view (inferior image from a four-chamber stack): (A) basilar LV short axis view, (B) three-chamber view, and (C) pericardial fat (asterisk) between chest wall and pericardial layers (arrowheads), and epicardial fat between pericardium and myocardium (double asterisk). Note that the visceral (also known as epicardium, serous) and parietal (fused serous and fibrous layers) pericardium are indistinguishable from each other and appear as one single thin line (arrowheads). The epicardium and parietal pericardium are visible as separate structures (white arrows) where the layers are separated by a small physiologic pocket of fluid as demonstrated in A. Each individual layer artificially appears thicker than the sum of the two because of an artifact whereby voxels containing both fluid and fat become black, thus creating black artificial lines that do not reflect the true anatomy. Another example of this artifact is noted between epicardial fat and the RV anterior free wall, where the separating artificial black line has no anatomic correlate. Note the pericardial reflection at the ascending aorta referred to as the superior aortic sinus (arrow in C).View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 7Black-blood fast SE sequence without fat suppression shows pericardial (asterisk) and epicardial (double asterisks) fat separated by epicardial and parietal pericardial layers (arrowheads) that appear inseparable as one thin line. The epicardial fat contains the coronary arteries and cardiac veins. Note that the right coronary artery (arrow) is surrounded by right atrioventricular groove fat.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The visceral pericardium is reflected to become continuous with the parietal pericardium as it invests the proximal segments of the great arteries, the venae cavae, and the pulmonary veins (Figure 8). The aorta and main pulmonary artery together are completely ensheathed in one investment with a bare area between them. A second investment separately covers the veins. These reflections of the serous pericardium between the arteries and the veins at the base of the heart form the pericardial sinuses and recesses. The transverse sinus is a passage that separates the arteries located anteriorly from the atria and veins posteriorly (Figure 9). This space lies behind the ascending aorta and main pulmonary artery and above the roof of the left atrium. It extends upward along the right side of the ascending aorta, where it forms the superior aortic recess between the aorta and the superior vena cava (SVC; Figure 10). It extends downward to the level of the aortic valve; the space between the ascending aorta and the right atrium is called the inferior aortic recess of the transverse sinus (Figure 11).20Vesely T.M. Cahill D.R. Cross-sectional anatomy of the pericardial sinuses, recesses, and adjacent structures.Surg Radiol Anat. 1986; 8: 221-227Crossref PubMed Scopus (27) Google Scholar The lateral extensions of the transverse sinus inferior to the proximal left and right pulmonary arteries are called the left and right pulmonic recesses, respectively. The postcaval recess is an extension of the pericardial cavity proper that lies behind and on the right lateral aspect of the SVC. It is separated from the transverse sinus by the reflection of the serous pericardium that covers the SVC across the right pulmonary artery and right superior pulmonary vein. The oblique sinus is a cul-de-sac located behind the left atrium delineated by the pulmonary veins and the inferior vena cava (IVC) and directly abuts the carina (Figure 12).Figure 10Contrast-enhanced computed tomographic nongated axial image shows the superior aortic recess of the transverse sinus (arrow).View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 11The superior aortic recess is indicated by the double asterisks. It is a space between the ascending aorta and SVC. The inferior aortic recess (asterisk) is a space between the aorta and the right atrium.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 12Contrast-enhanced computed tomographic nongated axial image shows the oblique sinus (arrow).View Large Image Figure ViewerDownload Hi-res image Download (PPT) The pericardial cavity normally contains <50 mL of serous fluid that can be detected in the superior aortic recess and transverse sinuses on CT.21Levy-Ravetch M. Auh Y.H. Rubenstein W.A. Whalen J.P. Kazam E. CT of the pericardial recesses.AJR Am J Roentgenol. 1985; 144: 707-714Crossref PubMed Google Scholar The pericardial fluid is an ultrafiltrate of plasma that comes from epicardial and parietal pericardial capillaries. It also contains prostaglandins secreted by mesothelial and endothelial cells that modulate cardiac reflexes and coronary tone.22Miyazaki T. Pride H.P. Zipes D.P. Prostaglandins in the pericardial fluid modulate neural regulation of cardiac electrophysiological properties.Circ Res. 1990; 66: 163-175Crossref PubMed Google Scholar, 23Mebazaa A. Wetzel R.C. Dodd-o J.M. Redmond E.M. Shah A.M. Maeda K. et al.Potential paracrine role of the pericardium in the regulation of cardiac function.Cardiovasc Res. 1998; 40: 332-342Crossref PubMed Scopus (38) Google Scholar Pericardial fluid is drained by the lymphatic system on the surface of the heart and in the parietal pericardium. The arterial supply of the pericardium comes from the pericardiophrenic and musculophrenic arteries, which are branches of the internal thoracic artery, and the descending thoracic aorta. Venous drainage is provided by pericardiophrenic veins that drain directly into or via the superior intercostal veins and internal thoracic veins to the innominate veins.24Yune H.Y. Klatte E.C. Mediastinal venography. Subselective transfemoral catheterization technique.Radiology. 1972; 105: 285-291Crossref PubMed Google Scholar The parasympathetic nerve supply of the pericardium is from the vagus and left recurrent laryngeal nerves as well as branches from the esophageal plexus. Sensory fibers from the phrenic nerve supply sensation to the pericardium. Sympathetic innervation is derived from the first dorsal ganglion, stellate ganglion and the aortic, cardiac, and diaphragmatic plexuses.25Holt J.P. The normal pericardium.Am J Cardiol. 1970; 26: 455-465Abstract Full Text PDF PubMed Scopus (50) Google Scholar The pericardium has a limited response to injury, which is manifested as exudation of fluid, fibrin, and inflammatory cells (Figure 13). Healing with organization may result in focal or diffuse obliteration of the pericardial cavity by adhesions between the visceral and parietal pericardium. Fibrous proliferation of the pericardium may predominantly involve only one of the serosal components or may involve both the parietal and visceral pericardium. Chronic effusions may be associated with pericardial thickening. At times, loculated accumulation of fluid may result in cardiac compression and a constrictive clinical picture. Calcific deposits may be focal or extensive and likely represent end-stage reaction to injury. The histologic features of excised pericardium for CP are generally nonspecific in terms of etiologic diagnosis and most often reflect a spectrum from organizing fibrinous pericarditis to organized fibrocalcific pericarditis. Pericardial late gadolinium enhancement (LGE) on CMR shows an association with the presence of granulation tissue and active inflammation with increased fibroblastic proliferation and neovascularization (Figure 14).26Zurick A.O. Bolen M.A. Kwon D.H. Tan C.D. Popovic Z.B. Rajeswaran J. et al.Pericardial delayed hyperenhancement with CMR imaging in patients with constrictive pericarditis undergoing surgical pericardiectomy: a case series with histopathological correlation.JACC Cardiovasc Imaging. 2011; 4: 1180-1191Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar