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Pericardial recesses. Anatomy and morphology with MDCT Poster No.: C-1399 Congress: ECR 2012 Type: Educational Exhibit Authors: D. Durany , M. vargas , J. C. Quintero , S. Vizcaya , A. Mariscal , 1 2 3 5 1 4 2 4 3 A. Olazábal ; Badalona barcelona/ES, baalona/ES, O Pereiro 4 5 de Aguiar (OURENSE)/ES, Badalona/ES, Barcelona/ES Keywords: Artifacts, Staging, Diagnostic procedure, CT, Thorax, Lymph nodes, Cardiac DOI: 10.1594/ecr2012/C-1399 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myESR.org Page 1 of 32 Learning objectives To show radiological features of pericardial recesses by MDCT axial, coronal and sagittal sections in order to avoid confusing them with mediastinal lymphadenopathy or other lesions. Background The pericardium is a "wrapper" around the heart and root of great vessels in the mediastinum. It facilitates the cardiac activity of the heart by decreasing the friction with the rest of surrounding mediastinal structures forming a defensive barrier to possible inflammation/infection of the heart. It has saccular morphology and has two main components: outer fibrous layer or fibrous pericardium and serous internal sac or serous pericardium. The latter consists of two layers: the epicardium or visceral pericardium and parietal pericardium. The parietal pericardium is located between the external fibrous layer and the pericardial cavity. At 2-3 cm from the exit of the thoracic great vessels (ascending aorta, main pulmonary artery and superior vena cava), the parietal pericardium turns on itself touching the adventitia of large vessels and forming the visceral pericardium. The space between the parietal pericardium and visceral pericardium is the pericardial cavity, which normally may contain from 15 to 50 ml of serous fluid. The visceral pericardium is intimately linked to the epicardial fat and cardiac surface. At CT the pericardium is visualized as a linear image of less than 2 mm of thickness. The pericardium is easily recognizable at CT because it is outlines by mediastinal fat (anteriorly) and epicardial fat (posteriorly). The presence of mediastinal fat helps to visualize the pericardium and pericardial recesses. Pericardial recesses are formed by extensions of the pericardial cavity when the visceral layer adapts to the entry of vessels into the heart or between them. Page 2 of 32 Pericardial recesses on MDCT are structures of low-attenuation near water (10-30UH), well defined, without walls or peripheral rings that limit them, in the typical locations of each of them. There's no intravenous contrast enhancement and they can be viewed even without the presence of pericardial effusion. Fig.1, Fig.2, Fig.3. Sometimes pericardial recesses have an interface pericardial fat adjacent to vascular structures that allow proper characterization. This is particularly common in the upper recesses. Another important feature of the pericardial recesses is their morphology, being very variable depending on the amount of fluid, location and in different spatial planes (multiplanar reconstructions: axial, coronal and sagittal) according to anatomical spaces. They can show different shapes: linear, crescent, punctate, ovoid, round, triangular, rhomboid; and some of them are more characteristic of certain recesses. Images for this section: Page 3 of 32 Fig. 1: Attenuation in Hounsfield units of a pericardial recess. Page 4 of 32 Fig. 2: PET-CT. Pericardial recesses do not show contrast enhancement or metabolic activity. Page 5 of 32 Fig. 3: PET-CT. Coronal image showing no contract enhancement and absence of metabolic activity. Page 6 of 32 Imaging findings OR Procedure details When the pericardium embraces several vessels entering and leaving the heart, it forms two tubular structures. The first one is the one that includes the aorta and pulmonary artery. The second is around the four pulmonary veins and both venae cavae, the superior and inferior. Fig. 4. Between the first and second tubular structure is a passage called the transverse sinus. Below the second tubular structure, there is a pouch called the oblique sinus, behind the left atrium. Fig. 5. The transverse sinus lies below and behind the ascending aorta and main pulmonary artery and above the left atrium. Fig. 6. The cranial extension of the transverse sinus creates superior aortic recess fitting directly into the aorta. The superior aortic recess has anterior, posterior and lateral subdivisions. The anterior portion of superior aortic recess extends in front of the ascending aorta and main pulmonary artery, adapting to the cleft between them (triangular). Fig. 7, Fig. 8. Laterally, it presents an extension to the aortic-pulmonary window, forming the recess of the aortic-pulmonary window (with a peak in the front). Fig.9, Fig. 10, Fig. 11. The posterior portion of the superior aortic recess is usually detected as a crescent behind the posterior wall of the ascending aorta. It can be detected an extension of the recess to the right paratracheal region (between the ascending aorta and the superior vena cava). Fig. 12, Fig. 13. The lower extention of transverse sinus originates the inferior aortic recess. The latter is located between the superior vena cava and right atrium on one side and ascending aortic root on the other. Page 7 of 32 The lateral extention of the transverse sinus originates the left and right pulmonic recesses. The right pulmonic recess is below the proximal right pulmonary artery and above the left atrium. Fig. 14, Fig. 15. The left pulmonary recess is bounded by the left pulmonary artery at the top, left superior pulmonary vein below and medially by the ligament of Marshall (remnant of the left superior vena cava). Fig. 16, Fig. 17, Fig. 18. Pericardial recesses, previously described, can mimic different conditions, the most common of these are the lymph nodes, but also aortic disease (dissection or thrombus), related to thymus or congenital (bronchogenic cyst). The oblique sinus is located in the posterior portion of the left atrium, anterior to the esophagus, separated from the transverse sinus by a double layer of pericardium (it may contain a fat plane between the two sheets of pericardium). The cranial portion of the oblique sinus is the posterior pericardial recess located between the distal right pulmonary artery and the intermediate bronchus. It can be confused with lymphadenopathy and esophageal disorders or injuries of the descending aorta. Fig. 19, Fig. 20, Fig. 21. There are two recesses not belonging to any of the above groups. Postcaval recess is a diverticulum of the pericardial cavity itself, which fits directly into the superior vena cava. Inferiorly, it continues with the cleft between the right pulmonary artery and right superior pulmonary vein. Fig. 22. The pulmonary veins recesses are usually located between the upper and lower veins of the right and left or accompanying them on their course. In inferior pulmonary veins, pericardial fluid may accompany the veins in front and behind them. There is no fatty tissue between the vascular structures and recess. Fig. 23, Fig. 24, Fig. 25. Images for this section: Page 8 of 32 Fig. 4: Pericardium embracing heart vessels. Page 9 of 32 Fig. 5: Transverse and oblique sinus. Page 10 of 32 Fig. 6: Transverse sinus. Page 11 of 32 Fig. 7: Anterior extension of superior aortic recess. Pericardial effusion. Page 12 of 32 Fig. 8: Anterior extension of superior aortic recess. No pericardium effusion. Page 13 of 32 Fig. 9: Axial view. Recess of the aortic-pulmonary window with oval morphology. Page 14 of 32 Fig. 10: Sagittal view. Recess of the aortic-pulmonary window with elongated morphology. Page 15 of 32 Fig. 11: Coronal view. Recess of the aortic-pulmonary window with fusiform morphology. Page 16 of 32 Fig. 12: Axial view. Posterior portion of superior aortic recess with crescent morphology. Page 17 of 32 Fig. 13: Coronal view. Posterior portion of superior aortic recess with fusiform morphology. Page 18 of 32 Fig. 14: Axial view. Right pulmonic recess. Page 19 of 32 Fig. 15: Coronal view. Right pulmonic recess. Page 20 of 32 Fig. 16: Axial view. Left pulmonic recess with elongated morphology. Page 21 of 32 Fig. 17: Coronal view. Left pulmonic recess with ovoid morphology. Page 22 of 32 Fig. 18: Sagital view. Left pulmonic recess with oval morphology. Page 23 of 32 Fig. 19: Axial view. Posterior pericardial recess with oval morphology. Page 24 of 32 Fig. 20: Sagittal view. Posterior pericardial recess with elongated morphology. Page 25 of 32 Fig. 21: Coronal view. Posterior pericardial recess with ovoid morphology. Page 26 of 32 Fig. 22: Postcaval recess. Page 27 of 32 Fig. 23: Axial view. Right pulmonary venous recess with nodular morphology. Page 28 of 32 Fig. 24: Sagittal view. Right pulmonary venous recess with crescent morphology. Page 29 of 32 Fig. 25: Coronal view. Right pulmonary venous recess with ovoid morphology. Page 30 of 32 Conclusion In the radiological study of oncological patients with MDCT is essential to recognize pericardial recesses in order to avoid misunderstandings that could lead to diagnostic and therapeutic errors and mistakes. MDCT (multidetector row computed tomography) with multiplanar reconstruction allows the rapid acquisition of scans, reducing heart and breathing motion artifacts, and due to greater anatomic resolution, it allows to recognize the several pericardial recesses in the absence of pericardial effusion. A comprenhensive knowledge of anatomy, the locations and typical morphological features of the pericardial recesses allow proper characterization. Pericardial recesses are common "pitfalls" in the diagnosis and staging of cancer patients in which the interpretation of a pericardial recess as a mediastinal lymph node can change neoplasia staging and alter their prognosis and treatment. Pericardial recesses are presented as images of variable morphology in the different planes of space, low attenuated to fit the cardiovascular structures. These structures are easily recognizable and they must not be confused with mediastinal lymphadenopathy or tumors that have a different CT appearance Familiarity of general radiologists with pericardial recesses should be recomended to avoid diagnostic errors. Personal Information [email protected] References Page 31 of 32 1- Truong MT, Erasmus JJ, Gladish GW, Sabloff BS, Marom EM, Madewell JE, Chasen MH, Munden RF. Anatomy of pericardial receses on multidetector CT: Implications for oncologic imaging. AJR 2003 Oct;181(4):1109-13. 2- Broderick LS, Brooks GN, Kuhlman JE. Anatomic pitfalls of the heart and pericardium. Radiographics2005 Mar-Apr;25(2):441-53. 3- Kodama F, Fultz PJ, Wandtke JC. Comparing thin-section and thick-section CT of pericardial sinuses and recesses. AJR 2003 Oct;181(4):1101-8. 4- Groell R, Schaffler GJ, Rienmueller R. Pericardial sinuses and recesses: findings at electrocardiographically triggered electron-beam CT. Radiology 1999 Jul;212(1):69-73. 5- O'leary SM, Williams PL, Williams MP, Edwards AJ, Roobottom CA, MorganHughes GJ, Manghat NE. Imaging the pericardium: appearances on ECG-gated 64-detector row cardiac computed tomography. Bristish Journal of Radiology 2010 Mar;83(987):194-205. 6- Vesely TM, Cahill DR. Cross-sectional anatomy of the pericardial sinuses, recesses and adjacent strcutures. Surgical and Radiologic Anatomy 1986;8(4):221-7. 7- Ozmen CA, Akpinar MG, Akay HO, Demirkazik FB, Ariyurek M. Evaluation of pericardial sinuses and receses with 2-, 4-, 16- and 64-row multidetector CT. Radiología Médica2010 Feb 22. Page 32 of 32