Peritoneum: Anatomy, physiology and pathology

Transcription

1 Peritoneum: Anatomy, physiology and pathology Poster No.: C-417 Congress: ECR 2009 Type: Educational Exhibit Topic: Abdominal and Gastrointestinal Authors: C. L. Fernandez Rey, I. Gutierrez Lopez, E. Montes Perez, S. M. Costilla Garcia, D. J. Gonzalez Suarez, A. Alvarez Cofiño; Oviedo/ ES Keywords: Peritoneum DOI: /ecr2009/C-417 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. Page 1 of 62

2 Learning objectives To describe the normal anatomy and pathology of the peritoneum. To discuss the usefulness of multidetector CT with multiplanar reformation in the evaluation of peritonel pathologies. Background Peritoneum is a large and thin serous membrane that lines peritoneal cavity and involves most abdominal viscera. Therefore peritoneum and peritoneal spaces are commonly affected in many primary and secondary pathologies. Radiologist must be familiar with the anatomy and physiology of peritoneum, as well as the spectrum of peritonel pathologies. Imaging findings OR Procedure details 1. ANATOMIC CONSIDERATIONS: WHAT RADIOLOGISTS MUST KNOW ABOUT THE PERITONEAL ANATOMY? The peritoneum is the largest serous membrane of the body that lines the internal abdominal wall and covers the bowel surface forming the tunica serosa The peritoneum delimites a virtual compartment called peritoneal cavity. It is a closed space in males but communicates with exterior through Fallopian tubes in females The peritoneal cavity is divided in supra and inframesocolic compartments by transverse mesocolon. Peritoneal ligaments and other anatomic structures divide these cavities in multiple spaces and subcompartments that are communicated between them. Peritoneal reflections: ligaments, omenta and mesenteries Ligaments connect two viscera supporting them and carrying the nutritional vessels. Omenta are peritoneal folds fixed to the stomach. The greater ometum descends from the greater gastric curvature,anterior to transverse mesocolon and small bowel. The lesser omentum is formed by gastrohepatic and hepatoduodenal ligaments. Page 2 of 62

3 Mesenteries are peritoneal reflections that connect the bowel to posterior abdominal wall Page 3 of 62

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5 : Peritoneal cavity (black arrow heads), Falciform ligament (white arrow heads), Right subphrenic space (1), Left subphrenic space (2), Liver (L), Pancreas (P), Stomach (S), Spleen (Sp) on page Page 5 of 62

6 : Hepatoduodenal ligament (1), Gastrocolic ligament (2), Gastrosplenic ligament (3), Liver (L), Stomach (S), Pancreas (P), Spleen (Sp) Page 6 of 62

7 : Peritoneal cavity (black arrow heads), Lesser sac (white arrow heads), Greater omentum (blue arrows), Liver (L), Pancreas (P), Stomach (S), Spleen (Sp) Page 7 of 62

8 : Peritoneal cavity (black arrow heads), subhepatic space (white arrow heads), Greater omentum (blue arrows), Liver (L), Small bowel (SB) Page 8 of 62

9 : Greater omentum (black arrow heads), Morison pouch (white arrow heads), Mesentery (1), Small bowel (SB) Page 9 of 62

10 : Root of the small bowel mesentery: Peritoneal reflection that fixes the small bowel to the posterior abdominal wall. It contains the superior mesenteric vessels Page 10 of 62

11 : Mesentery: It covers the small bowel surface forming the tunica serosa Page 11 of 62

12 : 1. Right subphrenic space; 2. Left perihepatic space; 3. Left subphrenic space; 4. Lesser sac; 5. Left paracolic gutter; 6. Morison Pouch Page 12 of 62

13 : Greater Omentum: The greater omentum descends from the gastric greater curvature anterior to transverse colon and small bowel Page 13 of 62

14 : Falciform Ligament: The falciform ligament extends between the anterior hepatic surface to diaphragm and anterior abdominal wall on page Page 14 of 62

15 : Lesser Omentum: The lesser omentum connects the lesser curvature of the stomach and duodenum to the liver and it is composed by hepatoduodenal and gastrohepatic ligaments Page 15 of 62

16 : Lesser sac: The lesser sac is a virtual compartment localized behinh to stomach and anterior to pancreas. It communicates with greater peritoneal cavity through The Winslow foramen Page 16 of 62

17 : Small bowel Mesentery: The small bowel mesentery is a broad fan-shaped fold of peritoneum that connects the small bowel to the posterior abdominal wall Page 17 of 62

18 : Root of mesentery ANATOMY AND PHYSIOLOGY: MESSAGES TO TAKE HOME Physiological and anatomic factors determine the location and the dissemination of peritoneal diseases: anatomic boundaries and physiologic flow of peritoneal fluid Generally fluid accumulate near the site of pathology origin. Example: fluid secondary to biliary pathology in perihepatic or right subphrenic spaces Dynamic peritoneal fluid: - First: The influence of gravity conduces the fluid to dependent recesses like Pouch of Douglas or Morison Pouch - Second: The influence of diaphragmatic movements that favors collections in subphrenic spaces Peritoneal compartments: Peritoneal ligaments and omenta function as anatomic barriers that limit the spread of pathologic processes. Page 18 of 62

19 Paracolic gutters extend between the ascending or descending colon and lateral abdominal wall. They are the major pathways between superior and inferior compartments. The right paracolic gutter is deep and wide and it communicates right subphrenic space with pelvis. However the left paracolic gutter is narrow and it is partially separated from the left subphrenic space by phrenicocolic ligament. The lesser sac is a virtual space between the stomach and the pancreas. The presence of fluid or dirty fat in the lesser sac suggests gastric / pancreatic pathology or peritoneal carcinomatosis. PATHOLOGY: A PICTORIAL REVIEW We present a diverse spectrum of both primary and secondary peritoneal pathologies including inflammatory conditions, tumor and tumor-like lesions, systemic diseases, traumatic and vascular processes, and internal hernias. We also discuss the key concepts in the diagnosis of the peritoneal diseases INFLAMMATORY CONDITIONS: Inflammatory or infectious processes involving the peritoneum or peritoneal cavity Secondary involvement is more frequent Localized processes: peritoneal abscesses Diffuse involvement: peritonitis Page 19 of 62

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26 TUMOR AND TUMOR LIKE LESIONS: Secondary malignant peritoneal involvement is more frequent than primary neoplasms Page 26 of 62

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39 SYSTEMIC DISEASES: A wide spectrum of systemic diseases may involve the peritoneum. The imaging features are non-specific and therefore the differential diagnosis with carcinomatosis peritoneal is usually difficult Page 39 of 62

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41 TRAUMATIC AND VASCULAR PROCESSES: Page 41 of 62

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44 INTERNAL HERNIAS: Viscera protrusion through the peritoneum or mesentery Page 44 of 62

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47 PERITONEAL PATHOLOGY: ROUTES OF SPREAD An understanding of possible pathways of pathologic processes is essential. If you know peritoneal anatomy you may predict how free fluid, extraluminal air, tumoral cells and inflammatory processes go through in peritoneum. This is very important to make a correct diagnosis. Page 47 of 62

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55 WHICH IMAGING FEATURES ARE USEFUL IN THE DIFFERENTIAL DIAGNOSIS OF PERITONEAL PATHOLOGIES? You must remember some key concepts: 1. The distribution and location of peritoneal free fluid can help narrow the differential diagnosis, for example the presence of fluid in the lesser sac suggests pancreatic / gastric pathology or peritoneal carcinomatosis 2. Differences between malignant and benign ascites: Proportionated fluid in the lesser sac and great peritoneal cavity suggests malignant ascites 3. Density of fluid collections: Increased attenuation of free fluid may suggest hemoperitoneoum, infection or inflammation 4. Mass effect: Tumoral conditions, abscesses and loculated ascitis present mass effect Page 55 of 62

56 5. Disproportionate fat stranding: When the degree of fat stranding is more severe than expected for the degree of gastrointestinal wall thickening you may suspect appendicitis, diverticulitis, omental infarct or epiploic appendagitis Page 56 of 62

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59 Images linked within the text of this section: : Hepatoduodenal ligament (1), Gastrocolic ligament (2), Gastrosplenic ligament (3), Liver (L), Stomach (S), Pancreas (P), Spleen (Sp) Page 59 of 62

60 : Lesser Omentum: The lesser omentum connects the lesser curvature of the stomach and duodenum to the liver and it is composed by hepatoduodenal and gastrohepatic ligaments Page 60 of 62

61 Conclusion Knowledge of anatomy and physiology is important to determine the origin, cause and extent of the peritoneal pathologies. Multidetector CT with multiplanar reformation improves the resolution of peritoneal spaces and the detection of pathologic conditions. Personal Information Cristina Fernandez Rey Department of Radiology, Hospital Universitario Central de Asturias, Oviedo, Spain References JC Healy, RH Reznek, Peritoneal anatomy, Imaging 12 (2000), 1-9, The British institute of radiology MS Shaw, JC Healy, RH Reznek, Imaging of peritoneum for malignant processes, Imaging 12 (2000), 21-23, The British institute of radiology PR Burn, JC Healy, Imaging benign peritoneal disease, Imaging 12 (2000), 34-48, The British institute of radiology Sobotta Atlas de Human Anatomy MH Floch, NR Floch, F. Netter, Netter s Gastroenterology. Peritoneum Federle, Jeffrey, Desser, Anne, Eraso, Diagnostic Imaging, Abdomen 2005, Amyrsis Meyers MA. Dynamic radiology of the abdomen. Meyers MA editos. Dynamic radiology of the abdomen: normal and pathological anatomy (2nd edn). New York, Springer, 1982 JM Pereira, CB Sirlin, PS Pinto, RB Jeffrey, DL Stella, G Casasola, Disproportionate fat stranding: a helpful CT sign in patient with acute abdominal pain, Radiographhics 2004, 24: PJ Woodward, R Sohaey, TP Mezzetti, Endometriosis: radiopathologic correlation, Radiographics 2001; 21: E. Yoo, JH Kim, MJ Kim et al, Greater and lesser omenta: Normal anatomy and pathologic processes, Radiographics 2007; 27: Page 61 of 62

62 S. Kim, TU Kim, JW Lee et al, The perihepatic space: Comprehesive anatomy and CT features of pathologic conditions, Radiographics 2007; 27: JH Demeo, AS Fulcher, RF Austin, Anatomic CT demonstration of the peritoneal spaces, ligaments and mesenteries: normal and pathologic processes, Radiogrpahics 1995; 15: JE Hamrick Turner, MV Chiechi, PL Abbitt, PR Ros, Neoplastic and inflammatory processes of the peritoneum, omentum and mesentery: Diagnosis with CT, Radiographics 1992; 12: PJ Pickhardt, S Bhalla, Unusual nonneoplastic peritoneal and subperitoneal conditions: CT findings, Radiographics 2005; 25: N Takeyama, T Gokam, Y Ohgiya et al, CT of internal hernias, Radiographics 2005; 25: Y Okino, H Kiyosue, H Mori et al, Root of small bowel mesentery: correlative anatomy and CT features of pathologic conditions, Radiographics 2001, 21: S Sheth, KH Horton, M R Garlad, EK Fishman, Mesenteric neoplasms: CT apperances of primary and secondary tumors and differential diagnosis, Radiographics 2003; 23: Page 62 of 62