Peritoneal cavity compartments: A pictorial review

Transcription

1 Peritoneal cavity compartments: A pictorial review Poster No.: C-1516 Congress: ECR 2010 Type: Educational Exhibit Topic: GI Tract Authors: T. C. Fernandes, R. H. Castro, N. P. Silva, A. B. Almeida, R. Cunha; Porto/PT Keywords: Anatomy, Peritoneal Cavity, Peritoneum DOI: /ecr2010/C-1516 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 36

2 Learning objectives The aim of this study is to review the anatomy of the peritoneal reflections and spaces illustrating it using pathologic processes that are confined and spread along the different compartments. Background The peritoneum is a continuous serous lamina that lines the abdominal walls and confines a wide and complex cavity, the peritoneal cavity. It is composed of two parts: the parietal and visceral peritoneum. The parietal peritoneum lines the inner wall of abdominopelvic cavity above, on the sides and anteriorly. Bellow it covers the urinary bladder, the seminal vesicles (in men), the uterus and ovaries (in women) and the rectum. Posteriorly it adheres to the anterior renal fascia. However, it moves away from the fascia at various levels to cover the second and third duodenal portions, the pancreas, and to give rise to the mesenteries and ligaments, limiting the spaces where the vasculonervous structures extend (subperitoneal spaces). The visceral peritoneum originates from the parietal peritoneal inflexions towards the abdominal cavity. It surrounds the hollow viscera and parenchymatous organs, connecting the organs to the abdominal wall and to one another. These connections assume different names according to the structures they join: Omenta - folds of peritoneum connecting the stomach with other organs. Mesenteries - folds of peritoneum connecting the intestines with the abdominal wall. Page 2 of 36

3 Ligaments - folds of peritoneum connecting organs to one another or to the abdominal wall. Computed tomography is one of the most effective imaging modality in evaluating peritoneal cavity pathology, with multiplanar reconstructions playing an important role in areas that might be difficult to evaluate on axial images. Imaging findings OR Procedure details THE PERITONEAL CAVITY: COMPARTMENTS The peritoneal cavity can be divided in three main regions: the supramesocolic; submesocolic; and the pelvic region. While the supra and submesocolic regions are separated by the transverse mesocolon but communicate on the sides along the paracolic gutter, the submesocolic region is in direct contact with the pelvic cavity. 1) Supramesocolic cavity The supramesocolic cavity is limited by the diaphragm above and the transverse colon bellow. It can be divided in four main spaces: Right subphrenic space; Right subhepatic space; Left subphrenic space; and the Lesser sac. To understand the complex anatomy of the supramesocolic compartment, some considerations concerning the ligaments that divide the various spaces are necessary: Falciform ligament, coronary ligaments and the bare area of the liver. The falciform ligament is a double fold of peritoneum that extends from the anterior abdominal wall to the liver, to surround it. At the level of the diaphragm the two folds separate to give rise to the coronary ligaments, that surround the bare area of the liver, which is not covered by the peritoneum. fig.1 on page 20 A) Right subphrenic space Page 3 of 36

4 - Located between the right hepatic lobe and the diaphragm. - Separated from the left subphrenic space by the falciform ligament. - Communicates with the right subhepatic space except on the posterior portion, where they are separated by the right coronary and triangular ligaments. - This space may be the site of fluid accumulation, abscesses and metastatic disease. fig. 2 Fig.: Fig.2 - Right subphrenic space. Axial contrast enhanced CT scan showing fluid accumulation and metastatic peritoneal implants (arrowheads) in the right subphrenic space (RSS), in a patient with ovarian tumor. Also note the falciform ligament (FL) and the right triangular ligament (RTL) limiting the RSS anterosuperiorly and posteroinferiorly respectively. L = liver. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL Page 4 of 36

5 B) Right subhepatic space - Surrounds the lower half of the right lobe of the liver. - Has two recesses: anterior and posterior. - The anterior recess continues above with the right subphrenic space and is closed below by the transverse mesocolon, except in the lateral portion where it communicates with the right paracolic gutter. - The posterior (or Morrison's) recess penetrates between the posterior wall of the liver and the superior portion of the right kidney, up to the right inferior coronary ligament, which separates this recess from the right subphrenic space. fig.3 Fig.: Fig.3 - Right subhepatic space. A) Axial and B) sagittal reformated contrast enhanced CT images, showing the anterior subhepatic recess (ASR) surrounding the lower right lobe of the liver (L) and the posterior subhepatic recess (PSR), confined between the liver and the anterior renal fascia. Note anterior communication (arrow) between the ASR and the right subphrenic space (RSS). References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL Page 5 of 36

6 C) Left subphrenic space This is a wide space limited above by the diaphragm and below by the transverse mesocolon and phrenocolic ligament. This space is made up of four communicating recesses fig.4 on page 20 e fig.5 Fig.: Fig.5 - Left subphrenic space. A) Axial and B) coronal reformatted contrast enhanced CT images showing the left subphrenic space filled with ascites. Note the gastrohepatic recess (GH), the immediate suphrenic recess (IS) and the perisplenic recess (PS). Note falciform ligament (FL) dividing it from the right subphrenic space, phrenocolic ligament (FCL) from the left paracolic gutter and gastrosplenic ligament (GSL) from the lesser sac. S= stomach; Sp=spleen. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL 1) The immediate subphrenic space: - Located between the diaphragm and the gastric fundus. - Is a common location for fluid accumulation, gastric processes and abscesses. Fig.6 Page 6 of 36

7 Fig.: Fig.6 - Left subphrenic space. Axial contrast enhanced CT scan shows a left subphrenic fluid collection (asterisk) with an air-fluid level (arrowhead), consistent with abscess. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL 2) The perisplenic recess - Surrounds the spleen and is limited inferiorly by the phrenocolic ligament, which inhibits the spread of pathologic processes to the left paracolic gutter. - Is a common location for fluid, abscesses and hemoperitoneum after splenic trauma. fig.7 Page 7 of 36

8 Fig.: Fig.7 - Perisplenic space. Coronal reformatted contrast enhanced CT image showing a fluid collection (asterisk) confined to the perisplenic recess. Note the collection doesn't spread to the left paracolic gutter, due to the phrenocolic ligament, that attaches the superior aspect of the descending colon to the diaphragm (not shown). S=spleen. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL Page 8 of 36

9 3) The left subhepatic (or gastrohepatic) recess - Located between the left hepatic lobe and the stomach. - Is usually affected by processes that involve the left hepatic lobe, lesser curvature of the stomach, duodenal bulb and the gallbladder. fig.8 Fig.: Fig.8 - A), B) -Axial contrast enhanced CT scans showing a left hepatic lobe abscess (asterisk) occupying the right subhepatic recess and compressing the stomach (S). Also note other smaller liver collections (arrows). References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL D) Lesser sac (omental bursa) Is the potencial space localized between the stomach and pancreas. Communicates with the remainder of the peritoneal cavity through the foramen of Winslow. Is divided in three main recesses (fig.9 on page 27): 1) Superior recess - Is identified above the pancreas and to the right of the midline on transverse sections. Page 9 of 36

10 - Extends upwards along the posteromedial face of the liver to the level of the diaphragm. 2) Splenic recess - Extends across the midline to the splenic hilum. - Is limited by the gastrohepatic ligament in the front, the gastrosplenic ligament laterally and the splenopancreatic ligament behind. 3) Inferior recess - Separates the stomach from the pancreas and transverse mesocolon. - Is the larger recess, and is located to the left of the midline. Although the peritoneal reflections forming the boundaries of the lesser sac are infrequently visualized in the normal patient, lesser sac lesions may be confidently diagnosed by the characteristic location between the stomach and pancreas. When an isolated fluid collection is encountered in the lesser sac, processes of pancreas, stomach and duodenum should be considered. fig 10, fig 11, fig 12 Page 10 of 36

11 Fig.: Fig.10 - Lesser sac. Axial contrast enhanced CT scan showing a mass between the stomach (S) and pancreas (P). Although the lesser sac ligaments are usually not visualized, this mass can confidently be attributed to the lesser sac since it appears between the stomach and pancreas. This mass was proved to be a gastric GIST. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL Page 11 of 36

12 Fig.: Fig.11 - Lesser sac pseudocyst. Axial contrast enhanced CT scan showing welldefined fluid collection (asterisk) confined to the lower compartment of the lesser sac, compatible with pseudocyst in a patient with recent history of pancreatitis. Note another independent fluid collection (arrow) in the body of the pancreas (P). S=Stomach. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL Page 12 of 36

13 Fig.: Fig.12 - Duodenal traumatic laceration. Axial contrast enhanced CT showing fluid and free air (red arrow) anteriorly to the pancreas (P), in the lesser sac. Also note a large amount of pneumoperitoneum centrally in midabdomen (red arrowheads) and dissection of the gas through the anterior pararenal space (white arrow) and perirenal space (white arrowhead). References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL 2) Submesocolic Cavity Corresponds to the space confined between the transverse mesocolon above and the sigmoid mesocolon bellow. It is divided in right and left inframesocolic compartments by the mesenteric root. These compartments are partially separated by the ascending and descending colon in the right and left paracolic gutters fig.13 Page 13 of 36

14 Fig.: Fig.13 - Inframesocolic cavity. Axial contrast enhanced sequential CT scans from A) the lower aspect of the liver (L) to D) the sigmoid mesocolon in a patient with ascites and peritoneal enhancement due to tuberculous peritonitis. A-C) Note division of the inframesocolic cavity in right (RIC) and left (LIC) inframesocolic compartments by the mesenteric root (M), and in right (arrowheads) and left (arrows) paracolic gutters by the ascending (AC) and descending (DC) colon. D) Note the transverse insertion of the sigmoid mesocolon (SM), which separates the inframesocolic cavity from the pelvic cavity. S=Sigmoid; L=Liver. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL 1) Right inframesocolic compartment - The right paracolic gutter communicates above with the right subhepatic space and extends downward into the right parasigmoidal space, and through this space into the pelvic cavity. Page 14 of 36

15 - The right paracolic gutter is a common site of fluid accumulation and metastatic deposition. - The ileocecal recesses are located above and bellow the terminal ileum and can harbour metastatic implants or being involved by inflammatory processes (e.g. appendicitis, Crohn's disease). fig 14 Fig.: Fig.14 - Inferior ileocolic recess. Axial contrast enhanced CT scan showing abscess (asterisk) adjacent to the cecum (C) and terminal ileum (I), compressing both structures, in a patient with appendicitis. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL 2) Left inframesocolic compartment Page 15 of 36

16 - The left paracolic gutter is closed above by the phrenocolic ligament, and is continues bellow with the left parasigmoidal space and the pelvic cavity. - The left paracolic gutter is a common site of fluid accumulation and metastatic deposition. fig 15 Fig.: Fig.15 - Left paracolic gutter. Axial contrast enhanced CT scans A) at the level of the transverse colon (T) and B) a few scans bellow, showing stranding of the mesenteric fat planes (asterisk), compatible with omental infarction. Note fluid accumulation in the paracolic gutter (arrows). Also note fluid in the perisplenic recess (arrowhead). D = descending colon. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL 3) Pelvic cavity Page 16 of 36

17 - Represents the extension of the submesocolic cavity to the pelvis, with which it widely communicates. - Is limited by parietal peritoneum that lines the abdominopelvic wall and reflects to cover the bladder, genital organs and rectum. - The deepest part of the peritoneal cavity lies posterior to the bladder and differs between man and women (fig.16 on page 33): 1) In females, the uterus subdivides this deep recess into the vesicouterine recess anteriorly, and the rectouterine recess (also called cull the sac or pouch of Douglas) posteriorly. The rectouterine recess is bounded anteriorly by the round ligaments and the uterus and posteriorly by the rectum, and is the most dependent portion of pelvis. It is a common location for fluid, drop metastases, primary pelvic malignancies and abscesses. fig 17 2) In men, the various communicating recesses between the bladder and rectum are combined to form a single space, called rectovesical space. Page 17 of 36

18 Fig.: Fig.17 - Rectouterine recess (pouch of Douglas). A) Axial and B) sagittal reformatted contrast enhanced CT images in a patient with right ovarian neoplasm. Note complex mass (asterisk) occupying the rectouterine recess, between the uterus (U) and the rectum (R). Also note a cystic mass in the left ovary (arrow). B=bladder. References: T. C. Fernandes; Radiology, Hospital de São João, Porto, PORTUGAL Page 18 of 36

19 Page 19 of 36

20 Images for this section: Page 20 of 36

21 Fig. 1: Fig.1 - Coronal drawing illustrating the posterior insertion of the ligaments that surround the bare area (BA) of the liver. See the falciform ligament (FL), which divides to give rise to the right (RCL) and left (LCL) coronary ligaments and right (RTL) and left (LTL) triangular ligaments. The falciform ligament divides the right (RSD) and left (LSD) subdiaphragmatic space. The bare area separates the suprahepatic spaces from the Page 21 of 36

22 right subhepatic space (RSH) and the lesser sac (LS), which communicates through the Winslow's foramen (curved arrow). Fig. 2: Fig.2 - Right subphrenic space. Axial contrast enhanced CT scan showing fluid accumulation and metastatic peritoneal implants (arrowheads) in the right subphrenic space (RSS), in a patient with ovarian tumor. Also note the falciform ligament (FL) and the right triangular ligament (RTL) limiting the RSS anterosuperiorly and posteroinferiorly respectively. L = liver. Page 22 of 36

23 Fig. 3: Fig.3 - Right subhepatic space. A) Axial and B) sagittal reformated contrast enhanced CT images, showing the anterior subhepatic recess (ASR) surrounding the lower right lobe of the liver (L) and the posterior subhepatic recess (PSR), confined between the liver and the anterior renal fascia. Note anterior communication (arrow) between the ASR and the right subphrenic space (RSS). Page 23 of 36

24 Fig. 4: Fig.4 - Subphrenic space and its recesses. Axial drawings A) at the level of the gastric fundus, showing the immediate subphrenic recess (IS) and B) at the level of the hepatic hilum, showing the gastrohepatic recess (Gh), confined between the stomach (S) and the liver (L), and limited posteriorly by the gastrohepatic ligament (ghl), the gastrosplenic recess (G) between the stomach and the spleen (Sp), and the perisplenic recess (PS) surrounding the spleen. gsl=gastrosplenic ligament. Fig. 5: Fig.5 - Left subphrenic space. A) Axial and B) coronal reformatted contrast enhanced CT images showing the left subphrenic space filled with ascites. Note the gastrohepatic recess (GH), the immediate suphrenic recess (IS) and the perisplenic recess (PS). Note falciform ligament (FL) dividing it from the right subphrenic space, phrenocolic ligament (FCL) from the left paracolic gutter and gastrosplenic ligament (GSL) from the lesser sac. S= stomach; Sp=spleen. Page 24 of 36

25 Fig. 6: Fig.6 - Left subphrenic space. Axial contrast enhanced CT scan shows a left subphrenic fluid collection (asterisk) with an air-fluid level (arrowhead), consistent with abscess. Page 25 of 36

26 Fig. 7: Fig.7 - Perisplenic space. Coronal reformatted contrast enhanced CT image showing a fluid collection (asterisk) confined to the perisplenic recess. Note the collection doesn't spread to the left paracolic gutter, due to the phrenocolic ligament, that attaches the superior aspect of the descending colon to the diaphragm (not shown). S=spleen. Page 26 of 36

27 Fig. 8: Fig.8 - A), B) -Axial contrast enhanced CT scans showing a left hepatic lobe abscess (asterisk) occupying the right subhepatic recess and compressing the stomach (S). Also note other smaller liver collections (arrows). Page 27 of 36

28 Fig. 9: Fig.9 - Lesser sac. A) Axial drawing of the lesser sac (dotted gray) at the level of the hepatic hilum, showing transverse extension behind the gastrohepatic ligament (ghl), stomach (S) and gastrosplenic ligament (gsl), and in front of the pancreas (P) and retroperitoneum. SpR =splenic recess. B) Parasagittal drawing. Note the superior recess (SR) between the posterior surface of the liver and the posterior parietal peritoneum, which communicates with the right subhepatic space through the foramen of Winslow (curved arrow). The inferior recess (IR) extends between the anterior and posterior reflexions of the greater omentum (go). S=stomach; T =transverse colon; tm=transverse mesocolon; D= duodenum. Peritoneum colored in purple. Fig. 10: Fig.10 - Lesser sac. Axial contrast enhanced CT scan showing a mass between the stomach (S) and pancreas (P). Although the lesser sac ligaments are usually not visualized, this mass can confidently be attributed to the lesser sac since it appears between the stomach and pancreas. This mass was proved to be a gastric GIST. Page 28 of 36

29 Fig. 11: Fig.11 - Lesser sac pseudocyst. Axial contrast enhanced CT scan showing welldefined fluid collection (asterisk) confined to the lower compartment of the lesser sac, compatible with pseudocyst in a patient with recent history of pancreatitis. Note another independent fluid collection (arrow) in the body of the pancreas (P). S=Stomach. Page 29 of 36

30 Fig. 12: Fig.12 - Duodenal traumatic laceration. Axial contrast enhanced CT showing fluid and free air (red arrow) anteriorly to the pancreas (P), in the lesser sac. Also note a large amount of pneumoperitoneum centrally in midabdomen (red arrowheads) and dissection of the gas through the anterior pararenal space (white arrow) and perirenal space (white arrowhead). Page 30 of 36

31 Fig. 13: Fig.13 - Inframesocolic cavity. Axial contrast enhanced sequential CT scans from A) the lower aspect of the liver (L) to D) the sigmoid mesocolon in a patient with ascites and peritoneal enhancement due to tuberculous peritonitis. A-C) Note division of the inframesocolic cavity in right (RIC) and left (LIC) inframesocolic compartments by the mesenteric root (M), and in right (arrowheads) and left (arrows) paracolic gutters by the ascending (AC) and descending (DC) colon. D) Note the transverse insertion of the sigmoid mesocolon (SM), which separates the inframesocolic cavity from the pelvic cavity. S=Sigmoid; L=Liver. Page 31 of 36

32 Fig. 14: Fig.14 - Inferior ileocolic recess. Axial contrast enhanced CT scan showing abscess (asterisk) adjacent to the cecum (C) and terminal ileum (I), compressing both structures, in a patient with appendicitis. Page 32 of 36

33 Fig. 15: Fig.15 - Left paracolic gutter. Axial contrast enhanced CT scans A) at the level of the transverse colon (T) and B) a few scans bellow, showing stranding of the mesenteric fat planes (asterisk), compatible with omental infarction. Note fluid accumulation in the paracolic gutter (arrows). Also note fluid in the perisplenic recess (arrowhead). D = descending colon. Fig. 16: Fig.16 - Posterior recesses of the pelvic cavity. A) Axial drawing of middle pelvic plane in women. Note separation of the vesicouterine (VUR) recess and the rectouterine recess (RUR) by the uterus (U) and round ligaments. B) Axial drawing of middle pelvic Page 33 of 36

34 plane in man showing communication of the all recesses posterior to the bladder, which form the rectovesical space (RVS). B= bladder; SV = seminal vesicles; R = Rectum. The peritoneum is colored in purple. The intraperitoneal pelvic cavity is colored in dotted gray. Fig. 17: Fig.17 - Rectouterine recess (pouch of Douglas). A) Axial and B) sagittal reformatted contrast enhanced CT images in a patient with right ovarian neoplasm. Note complex mass (asterisk) occupying the rectouterine recess, between the uterus (U) and the rectum (R). Also note a cystic mass in the left ovary (arrow). B=bladder. Page 34 of 36

35 Conclusion A thorough knowledge of the various spaces and their connections within the peritoneal cavity helps in the challenging process of narrowing the differential diagnosis list of a given pathologic finding. Personal Information Teresa Fernandes (te_fernandes@hotmail.com) Department of Radiology of Hospital S. João - Porto, Portugal Head of Department - Professora Doutora Isabel Ramos Oporto Medical School References 1. DeMeo JH, Maj ASF, Austin RE. Anatomic CT Demonstration of the Peritoneal Spaces, Ligaments, and Mesenteries: Normal and Pathologic and Pathologic Processes. RadioGraphics 1995; 15: Min PQ, Yang ZG, Lei QF, Long WS, Jiang SM, Zhou, DM Peritoneal Reflections of Left Perihepatic Region: Radiologic-Anatomic Study. Radiology 1992; 182: Hamrick-Turner JE, Chiechi MV, Abbitt PL, Ros PR. Neoplastic and inflammatory processes of the peritoneum, omentum, and mesentery: diagnosis with CT. RadioGraphics 1992; 12: Dodds WJ, Foley WD, Lawson IL, Stewart ET, Taylor A. Anatomy and imaging of the lesser peritoneal sac. AJR 1985; 144: Page 35 of 36

36 5. Meyers MA, Oliphant M, Berne AS, Feldberg MAM. The peritoneal ligaments and mesenteries: pathways of intraabdominal spread of disease. Radiology 1987; 163: Silverman PM, Baker ME, Cooper C, Kelvin FM. Computed tomography of mesenteric disease. RadioGraphics 1987; 7: Rubenstein WA, Auh YH, Whalen JP, Kazam E. The penihepatic spaces: computed tomographic and ultrasound imaging. Radiology 1983; 149: Jolles H, Coulam CM. CT of ascites: differential diagnosis. AJR 1980; 135: Siegelman SS, Copeland BE, Saba GP, Cameron JL, Sanders RC, Zerhouni EA. CT of fluid collections associated with pancreatitis. AJR 1980; 134: Jeffrey RB, Federle MP, Crass RA. Computed tomography of pancreatic trauma. Radiology 1983; 147: Page 36 of 36