retropertioneo

8/10/2019 retropertioneo

1/37

Page 1 of 37

Extraperitoneal Space: Anatomic and Radiologic Overview

Award: Certificate of Merit

Poster No.: C-2250

Congress: ECR 2014

Type: Educational Exhibit

Authors: M. Horta 1, N. Neto 2, C. Couceiro 1, L. P. Martins 1; 1Lisbon/PT,2Lisboa/PT

Keywords: Education and training, Diagnostic procedure, MR, CT, Anatomy,Abdomen

DOI: 10.1594/ecr2014/C-2250

Any information contained in this pdf file is automatically generated from digital materialsubmitted to EPOS by third parties in the form of scientific presentations. Referencesto any names, marks, products, or services of third parties or hypertext links to third-

party sites or information are provided solely as a convenience to you and do not inany way constitute or imply ECR's endorsement, sponsorship or recommendation of thethird party, information, product or service. ECR is not responsible for the content ofthese pages and does not make any representations regarding the content or accuracyof material in this file.As per copyright regulations, any unauthorised use of the material or parts thereof aswell as commercial reproduction or multiple distribution by any traditional or electronicallybased reproduction/publication method ist strictly prohibited.You agree to defend, indemnify, and hold ECR harmless from and against any and allclaims, damages, costs, and expenses, including attorneys' fees, arising from or relatedto your use of these pages.Please note: Links to movies, ppt slideshows and any other multimedia files are notavailable in the pdf version of presentations.www.myESR.org


2/37


3/37

Page 3 of 37

Fig. 1 : Diagram showing the anatomic limits of the extraperitoneal space and of theretroperitoneum.References: Horta M, Lisbon/Portugal

The retroperitoneal space is a huge compartment of the extraperitoneal space locatedin the posterior abdomen, that lies posteriorly to the parietal peritoneum and anteriorly tothe transversalis fascia and the posterior abdominal wall (figure 1). It extends from thediaphragm superiorly to the pelvis inferiorly [2,3]. Anteriorly, it is continuous with the root

of the small bowel mesentery and with the transverse mesocolon (figure 2) [2].


4/37

Page 4 of 37

Fig. 2 : Illustration showing the contiguity of the retroperitoneal space (anteriorpararenal space) with the root of the mesentery (arrow) and the anterior pararenalposition of the ascending colon after the rotations and fusions of the dorsal mesentery(arrowhead).References: Horta M, Lisbon/Portugal

The renal fascia is a sheath of collagenous connective tissue that encapsulates thekidneys, the adrenal glands and the perirenal fat. It is divided in an anterior layer (Gerota'sfascia) and in a posterior layer (also known as Zuckerkandl's fascia). These two layers

join in the lateral parts of the kidneys, behind the ascending and descending colon, to formthe lateroconal fascia , that then continues along the flank and fuses with the parietalperitoneum (figure 3).


5/37

Page 5 of 37

Fig. 3 : Diagram (A) and axial CT image (B) show the renal fascia, its anterior andposterior layers, and its relation with lateroconal fascia.References: Illustration: Horta M, Lisbon/Portugal. CT image: Department ofRadiology, Centro Hospitalar Lisboa Ocidental, Lisbon/Portugal.

The renal fascia conventionally divides the retroperitoneum into three distinctcompartments: the anterior pararenal space; the perirenal space and the posteriorpararenal space (figure 4) [2-5].

Fig. 4 : Illustration showing the anterior pararenal space, the perirenal space, theposterior pararenal space and their anatomical limits.References: Horta M, Lisbon/Portugal

The anterior pararenal space is bounded anteriorly by posterior parietal peritoneum,posteriorly by the anterior renal fascia and postero-externally by the lateroconal fascia(figure 4).


6/37

Page 6 of 37

It can potentially be continuous across the midline and it extends from the dome of thediaphragm to the pelvis, communicating with the posterior pararenal space below theperirenal cone [6]. Anteriorly, it communicates with the root of the small bowel mesenteryand with the transverse mesocolon (figure 5) [2].

It contains structures that were developed in the embryologic dorsal mesentery and thatbecame secondarily retroperitoneal after mesentery rotations and fusions, such as theascending and descending colon, most of the pancreas (with exception of the tail that isintraperitoneal) and the retroperitoneal portions of the duodenum (figure 2) [1,3,4].

Lesions of these organs are responsible for the high number of infections that occur inthis space, being the most common site of extraperitoneal infection. Effusions come fromperforating neoplasms, peptic ulcers, inflammatory conditions and trauma. Perforation ofan ascending retrocecal appendix can also lead to an abscess in this space. Bleedingfrom the bare area of the liver and from the splenic and hepatic arteries has been seen(figure 5) [2].

Fig. 5 : A 84-year-old woman with pancreatitis. Axial contrast-enhanced CT scan (Aand B), show pancreatic fluid and inflammation extending from the pancreas in theanterior pararenal space (APS), straddling the midline. Note its anterior communication


7/37

Page 7 of 37

with the root of small bowel mesentery (B, circle). Sagittal contrast-enhanced CT scan(C and D), demonstrates de extension of the anterior pararenal, that reaches superiorlythe diaphragm (C, arrow). The perirenal and the posterior pararenal spaces are spared(A-D).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ Portugal

The perirenal space is surrounded by the renal fascia and contains the kidneys, theadrenal gland, the proximal ureter, fat and lymphatics (figures 6A-C).

It has the form of an inverted long tapered cone, caused by the ascent of the kidneysfrom its pelvic location in early embryologic life to their adult position (figure 6D) [1,4].

Fig. 6 : The perirenal space. Axial contrast-enhanced CT scan (A-C), show theconstituents and the anatomic limits of the perirenal space; adrenal glands (red circles);kidneys (K); ureters (yellow circles); fat (F); Gerota's fascia (G); Zuckerkandl's fascia(Z). Note the inverted long tapered cone appearance in sagittal contrast-enhanced CTimages (D,E).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ PortugalThere are inconsistencies in the literature whether the perirenal spaces have continuityacross midline [6].

According to Meyers, they do not communicate with each other. Internally, the thinanterior renal fascia fuses with the connective tissue surrounding the great vessels andthe thicker Zuckerkandl's fascia joins the psoas and quadratus lomborum fascia (figure7, arrows) [2]. On the other hand, studies conducted by Mindell et al., Thornton et al.and Kneeland et al., demonstrated communication across midline between the perirenalspaces [6-8]. This communication was shown at and below the level of the hila or superior


8/37

Page 8 of 37

mesenteric artery, since above this level the coeliac axis and the superior mesenteryartery prevent free communication [6-9].

Fig. 7 : Non-contrast-enhanced axial CT scan of a fluid collection in the left perirenalspace and along the psoas muscle. CT demonstrates the accentuated renal fascialplanes, showing the anterior renal fascia blending with connective tissue surroundingthe great vessels and the posterior renal fascia joining the quadratus lomborum fascia

(arrows).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ Portugal

Inferiorly, there is also no consensus whether the inferior aspect of the renal cone isclosed (figure 6E). Some investigators support that it communicates freely with the pelvicextraperitoneal spaces [6,7,9]. Others, suggest that anterior and posterior fascia fuse


9/37

Page 9 of 37

below the kidneys, preventing the extension of perirenal fluid collections to the pelvis, sothat the effusions stay confined within the perirenal space [2,9,10].

On the right side, over the right kidney and the adrenal gland, the anterior renal fasciais deficient and the perirenal space abuts and opens to the bare area of the liver[2,9,11]. Consequently, pathologic processes can extend upward into the bare area anddownward into the perirenal space (figure 8). On the left it opens towards the subphrenicspace [9,11].

Fig. 8 : Extension of a pneumoretroperitoneum to the bare area of the liver. Note thecontiguity between the right perirenal space and the bare area of the liver.References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ PortugalThe perirenal space contains thin bridging septa that transverse the perirenal fat,connecting the renal capsule to perirenal fascia and interconnecting its two layers (figure9). Thickened fibrous lamellae may be an early sign of renal/perirenal disease and maydirect the spread of fluid, inflammation or neoplasms from the kidney to the perirenalinterfascial plane and vice versa [1,12].


10/37

Page 10 of 37

Fig. 9 : Illustration showing the three types of perirenal bridging septa, those that arisefrom the renal capsule and extend to the renal fascia, those that are only connect to therenal capsule and those that interconnect the anterior and posterior renal fasciae. AxialCT scan show thickened perinephric bridging septa in a patient with no pathology.References: Illustration: Horta M, Lisbon/ Portugal. CT image: Department ofRadiology, Centro Hospitalar Lisboa Ocidental, Lisbon/PortugalSmall lymph nodes and a rich network of lymphatics can be found in the perirenal space.They communicate with hilar and paraaortic lymph nodes as well as with transpleural andtransdiaphragmatic lymphatics, providing a route of spread for neoplasms to and fromthe perirenal space [12].

Abscess due to renal infection, urinomas resulting from chronic disruption of the collectingsystem and hematomas caused more frequently by trauma and neoplasms are the maineffusions encountered in this space [2].

The posterior pararenal space is a small space that only contains fat and no organs,lying between the posterior renal fascia and the transversalis fascia (figure 10A) [2].

Inferiorly, below the renal cone, it merges with the anterior pararenal space,communicating with the extraperitoneal compartments of the pelvis (figures 10C-E) [13].

The posterior pararenal space continues externally to the lateroconal fascia as theproperitoneal fat (figure 10A, orange arrow) [2,11]. Properitoneal fat is radiologicallyvisualized as the "flank stripe", being bound by lateroconal fascia internally andtransversalis fascia externally (figure 10A, PPF). Both posterior pararenal spaces can

potentially communicate via the properitoneal fat of the anterior abdominal wall [2,11].

At the level of the inferior aspect of the renal cone, when the anterior and posteriorpararenal spaces merge, the lateroconal fascia disappears so that the anterior pararenalspace stays in communication with the properitoneal fat (figure 10E) [2].


11/37

Page 11 of 37

The posterior renal fascia was shown to be divided at variable distance of theposterolateral aspect of the kidneys in one thin anterior layer that continues with theanterior perirenal fascia and in one thick posterior layer that continues with the lateroconalfascia (figure 10B). Between these two layers a potential anatomic space exists thatcommunicates freely with the anterior pararenal space [2].

Fig. 10 : Non-contrast-enhanced axial CT. Figure A shows the pararenal posteriorspace (PPS), bounded by the transversalis fascia (TF) and the posterior renal fascia(Z). Note its anatomic contiguity with the properitoneal fat (PPF, orange arrow), that isbound by the lateroconal fascia (LCF) internally and the transversalis fascia externally.The posterior renal fascia is shown to be divided in one layer that continues with theanterior renal fascia and in one posterior layer that continues with LCF (B). Figures C-Eshow the inferior extension of the PPS. At the inferior aspect of the renal cone the LCFdisappears (E).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ PortugalThe posterior renal space is a common site of hemorrhage from a ruptured abdominalaneurysm as well as of spontaneous hemorrhage due to blood anticoagulation and blood

diathesis. Infection is not typically limited to this space, however effusions from spinalosteomyelitis or from a perforated rectum or sigmoid may spread into this compartment[2].


12/37

Page 12 of 37

Some authors describe a fourth space called the great vessel space , that contains theaorta and inferior vena cava. It is bounded laterally by the perirenal space and extendssuperiorly to the posterior mediastinum. Retroperitoneal fibrosis is usually confined tothis space [4].

Interfascial retroperitoneal planes

More recent studies documented the existence of interfascial retroperitoneal planes.They demonstrated that the renal fascia was composed of multiple layers of variablefused embryonic mesentery, originating potential spaces in the retroperitoneum thatcould be recruited when a large amount of fluid developed rapidly, serving as pathwaysfor the spreading and decompression of various pathologic entities [1,4,5,14].

These potential spaces are the retromesenteric space , the retrorenal space , thelateroconal plane and the combined interfascial plane [1,4,5].

The retromesenteric plane is located between the anterior pararenal space and theperirenal space (figure 11) [12]. It is continuous across midline providing a major routeof contralateral retroperitoneal fluid spread [1,4,5].

On the right side it abuts the bare area of the liver and is contiguous with the liver hilumthrough the subperitoneal space of the hepatoduodenal ligament. On the left it extends tothe dome of diaphragm, posterior to the esophagus and the phrenoesophageal ligament[4,5].

Inferiorly, the retromesenteric plane extends to the pelvis along the anterior surface ofthe psoas [1].

The retromesenteric plane communicates with the retrorenal and lateroconal interfascialplanes at the fascial trifurcation , which is another a potential space at the origin of thelateroconal fascia where these three spaces meet each other (figure 11) [5].


13/37

Page 13 of 37

Fig. 11 : Warfarin-induced haemorrhage in a 33-year-old man. Contrast-enhancedaxial CT shows haemorrhage in the anterior interfascial retromesenteric plane(straight open arrow), in the posterior interfascial retrorenal plane (solid arrow) andin the lateroconal interfascial plane (curved arrow). These three interfascial planescommunicate with each other at the fascial trifurcation (yellow circle). Collapseddescending colon (arrowhead).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ Portugal

The retrorenal plane is the interfascial plane located between the perirenal space andthe posterior pararenal space (figure 11) [4,12]. It communicates with the great vesselspace which impedes their communication through midline [4,5]. Effusions from the


14/37

Page 14 of 37

anterior pararenal space and retromesenteric space may extend into the retrorenal space(figure 11) [4,5].

The lateroconal interfascial plane is a potentially space between the layers of thelateroconal fascia, that communicates with the retrorenal and retromesenteric planes atthe level of the fascial trifurcation (figure 11) [4,5,12].

The combined interfascial plane results from the inferior fusion of the retrorenal andretromesenteric interfascial planes, posterior to the ascending and descending colon. Itcontinues inferiorly along the surface of the psoas into the mesorectal interfascial planeor prevesical space (figure 12A) [5]. This plane allows the spread of effusions from theabdominal retroperitoneum to the pelvic retroperitoneum and vice versa [4,5].

Fig. 12 : Retroperitoneal fluid collections in a patient with necrotizing pancreatitis.Contrasted-enhanced sagittal CT and contrasted-enhanced axial CT at the level ofthe lower poles of kidneys show fluid collections in the left retromesenteric plane(open arrows) and in the left retrorenal plane (solid arrows). These two planes fuse

to form a single multilaminar fascia, the combined interfascial plane ( A, solid lines),that allows the spread of effusions from the abdominal retroperitoneum to the pelvicretroperitoneum.References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ Portugal


15/37

Page 15 of 37

Images for this section:

Fig. 1: Diagram showing the anatomic limits of the extraperitoneal space and of theretroperitoneum.


16/37

Page 16 of 37

Fig. 2: Illustration showing the contiguity of the retroperitoneal space (anterior pararenalspace) with the root of the mesentery (arrow) and the anterior pararenal position of theascending colon after the rotations and fusions of the dorsal mesentery (arrowhead).

Fig. 3: Diagram (A) and axial CT image (B) show the renal fascia, its anterior and posteriorlayers, and its relation with lateroconal fascia.


17/37

Page 17 of 37

Fig. 4: Illustration showing the anterior pararenal space, the perirenal space, the posteriorpararenal space and their anatomical limits.

Fig. 5: A 84-year-old woman with pancreatitis. Axial contrast-enhanced CT scan (A and

B), show pancreatic fluid and inflammation extending from the pancreas in the anteriorpararenal space (APS), straddling the midline. Note its anterior communication with theroot of small bowel mesentery (B, circle). Sagittal contrast-enhanced CT scan (C andD), demonstrates de extension of the anterior pararenal, that reaches superiorly thediaphragm (C, arrow). The perirenal and the posterior pararenal spaces are spared (A-D).


18/37

Page 18 of 37

Fig. 6: The perirenal space. Axial contrast-enhanced CT scan (A-C), show theconstituents and the anatomic limits of the perirenal space; adrenal glands (red circles);kidneys (K); ureters (yellow circles); fat (F); Gerota's fascia (G); Zuckerkandl's fascia(Z). Note the inverted long tapered cone appearance in sagittal contrast-enhanced CTimages (D,E).


19/37

Page 19 of 37

Fig. 7: Non-contrast-enhanced axial CT scan of a fluid collection in the left perirenal spaceand along the psoas muscle. CT demonstrates the accentuated renal fascial planes,showing the anterior renal fascia blending with connective tissue surrounding the greatvessels and the posterior renal fascia joining the quadratus lomborum fascia (arrows).


20/37

Page 20 of 37

Fig. 8: Extension of a pneumoretroperitoneum to the bare area of the liver. Note thecontiguity between the right perirenal space and the bare area of the liver.

Fig. 9: Illustration showing the three types of perirenal bridging septa, those that arisefrom the renal capsule and extend to the renal fascia, those that are only connect to therenal capsule and those that interconnect the anterior and posterior renal fasciae. Axial

CT scan show thickened perinephric bridging septa in a patient with no pathology.


21/37

Page 21 of 37

Fig. 10: Non-contrast-enhanced axial CT. Figure A shows the pararenal posterior space(PPS), bounded by the transversalis fascia (TF) and the posterior renal fascia (Z). Noteits anatomic contiguity with the properitoneal fat (PPF, orange arrow), that is bound by thelateroconal fascia (LCF) internally and the transversalis fascia externally. The posteriorrenal fascia is shown to be divided in one layer that continues with the anterior renal fasciaand in one posterior layer that continues with LCF (B). Figures C-E show the inferiorextension of the PPS. At the inferior aspect of the renal cone the LCF disappears (E).


22/37

Page 22 of 37

Fig. 11: Warfarin-induced haemorrhage in a 33-year-old man. Contrast-enhanced axialCT shows haemorrhage in the anterior interfascial retromesenteric plane (straight openarrow), in the posterior interfascial retrorenal plane (solid arrow) and in the lateroconalinterfascial plane (curved arrow). These three interfascial planes communicate with eachother at the fascial trifurcation (yellow circle). Collapsed descending colon (arrowhead).


23/37

Page 23 of 37

Fig. 12: Retroperitoneal fluid collections in a patient with necrotizing pancreatitis.Contrasted-enhanced sagittal CT and contrasted-enhanced axial CT at the level of thelower poles of kidneys show fluid collections in the left retromesenteric plane (openarrows) and in the left retrorenal plane (solid arrows). These two planes fuse to form asingle multilaminar fascia, the combined interfascial plane ( A, solid lines), that allows thespread of effusions from the abdominal retroperitoneum to the pelvic retroperitoneum.


24/37

Page 24 of 37

Findings and procedure details

Pancreatitis

The absence of a capsule around the pancreas allows easy access to pancreatic

enzymes to spread to multiple anatomic compartments around the pancreas when acuteinflammation occurs.

Fluid collections are commonly present in the anterior pararenal space, in the interfascialplanes, in the lesser sac and in the subperitoneal spaces of transverse mesocolon andof the small bowel mesentery [1,5].

Since the pancreas is mostly located in the anterior pararenal space, the involvement ofthis retroperitoneal space is typical (figure 5). However, bilateral spread is usually onlyseen in advanced stages of fulminant necrotizing pancreatitis [2].

Pancreatic effusions commonly infiltrate the anterior interfascial retromesenteric planeand extend to the contiguous retrorenal interfascial plane (figure 13). Involvement of thelateroconal plane is sometimes seen. They may spread inferiorly along the combinedinterfascial plane to the pelvic retroperitoneal spaces [1,5].

The classical clinical sign of Grey-Turner (subcutaneous discoloration of thecostovertebral angle) is caused by the spread of pancreatic effusion to the retrorenalinterfascial plane. From this space it reaches the subcutaneous tissues of the posteriorabdominal wall areas of anatomic weakness (the Grynfeltt and Petit triangles) through acleft between the medial border of the posterior pararenal space and the lateral borderof quadratus lomborum fat pad [1,2,4].


25/37

Page 25 of 37

Fig. 13 : Necrotizing pancreatitis in a 75-year-old woman. Contrast-enhanced CTscan (A-D) show bilateral spread of pancreatic effusion within the retromesentericinterfascial planes (open arrows), dissecting posteriorly into the left retrorenal space

(solid arrows; yellow line). The right retromesenteric plane communicates with the liverhilum through the subperitoneal space of the hepatoduodenal ligament (yellow circle).Note the extension of the left retromesenteric plane and the retrorenal plane to lefthemidiaphragm (orange circle).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ Portugal

Ruptured abdominal aortic aneurysms

The most common CT finding indicating rupture of an abdominal aortic aneurysm is aretroperitoneal hematoma [15]. Bleeding from a ruptured aortic aneurysm may extendinto the pararenal spaces, the perirenal space or the psoas muscle [15].

Most commonly they bleed posteriorly and are circumscribed by the psoas space [5].Frequently, bleeding extends to the posterior pararenal space or into the retrorenal planethat is usually involved due to its medial relation to the great vessel space[2,5].The


26/37

Page 26 of 37

combined interfascial plane can be dissected upward and downward by haemorrhage[5] (figure 14).

Fig. 14 : Rupture of abdominal aortic aneurysm is a 73-year-old man. Axialcontrast-enhanced CT images (A,B) and sagittal contrast-enhanced CT image(C) demonstrate a large ruptured abdominal aortic aneurysm with a prominentretroperitoneal haemorrhage. Haemorrhage is predominantly located in the left anteriorretromesenteric space, crossing the midline. The hematoma also extends to the leftretrorenal space, to the left combined interfascial plane and to a lesser extent, to thebridges of the perirenal space (B,C).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ Portugal

Perirenal hematoma

Both subcapsular and perirenal hematomas can be caused by trauma or by lesions ofthe kidneys and of their blood vessels [2]. They can spread into the adjacent interfascialplanes along the perinephric bridging septa (figure 15) [1].


27/37

Page 27 of 37

Fig. 15 : Subcapsular and perirenal left hematoma caused by a stab wound. Contrast-enhanced axial CT scan (A-C) and contrast-enhanced sagittal images (C,D) depict asubcapsular and perinephric left renal hematoma. Note the thickened perirenal bridgingsepta (small arrows) serving as conduit for the spread of fluid to the retrorenal planeand to the anterior renal fascia (open arrow).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ Portugal

Perirenal abscess

The majority of perirenal abscess are usually a sequela of an acute pyelonephritis [2].They may also originate from infection of a pre-existing hematoma or urinoma [16].Perforation of the renal capsule leads to the involvement of the perirenal space. On CTa fluid collection with a thick enhancing wall is usually seen within the renal parenchymaand within the perirenal space. Intralesional gas may be present (figure 16) [16].


28/37


29/37

Page 29 of 37

Fig. 17 : Extraperitoneal air in a 83-year-old woman with a iatrogenic perforation of thesigmoid. Axial CT scan obtained without intravenous contrast material (A-D) depictsgas within the presacral space (red arrow) and within the perirectal space (yellowarrow) dissecting into the prevesical space (green arrow). Cephalad extension ofthe gas through the combined interfascial plane is demonstrated (C, circle and line;D). The pneumoretroperitoneum penetrates into the perirenal space and into theretromesenteric interfascial plane (D, blue arrow). Note the presence of gas in theposterior pararenal space and in the extraperitoneal anterolateral abdominal wall (whitearrow).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ Portugal

Spontaneous retroperitoneal warfarin-induced haemorrhage


30/37

Page 30 of 37

Spontaneous retroperitoneal haemorrhage is defined as the presence of bleeding from anon traumatic and non iatrogenic cause without any underlying retroperitoneal pathology[18].

Haemorrhage associated with anticoagulation and bleeding diathesis commonly involvesbody wall muscle compartments, such as the ileopsoas muscle (figure 18) [19].

The patient typically presents with lower extremity pain and paraesthesia in the territoriesof the lumbar plexus [18].

Perirenal and posterior pararenal spaces hematomas are not rare [2,19].

Fig. 18 : 77-year-old woman with a retroperitoneal warfarin-induced hematoma.Axial CT scan obtained with intravenous contrast material (A-F) depicts an extensivehematoma along the psoas compartment (yellow asterisks), that extends to theposterior renal space and a large hematoma in the anterior pararenal space (purpleasterisks). Note the presence of hydronephrosis caused by the compression of the

perirenal space (open arrow). Thickened bridging septa are seen providing a conduitfor the spread of fluid into the perirenal space (small arrows).References: Department of Radiology, Centro Hospitalar Lisboa Ocidental, Lisbon/ Portugal

Images for this section:


31/37

Page 31 of 37

Fig. 13: Necrotizing pancreatitis in a 75-year-old woman. Contrast-enhanced CT scan(A-D) show bilateral spread of pancreatic effusion within the retromesenteric interfascialplanes (open arrows), dissecting posteriorly into the left retrorenal space (solid arrows;

yellow line). The right retromesenteric plane communicates with the liver hilum throughthe subperitoneal space of the hepatoduodenal ligament (yellow circle). Note theextension of the left retromesenteric plane and the retrorenal plane to left hemidiaphragm(orange circle).

Fig. 14: Rupture of abdominal aortic aneurysm is a 73-year-old man. Axial contrast-enhanced CT images (A,B) and sagittal contrast-enhanced CT image (C) demonstrate a


32/37

Page 32 of 37

large ruptured abdominal aortic aneurysm with a prominent retroperitoneal haemorrhage.Haemorrhage is predominantly located in the left anterior retromesenteric space,crossing the midline. The hematoma also extends to the left retrorenal space, to the leftcombined interfascial plane and to a lesser extent, to the bridges of the perirenal space(B,C).

Fig. 15: Subcapsular and perirenal left hematoma caused by a stab wound. Contrast-enhanced axial CT scan (A-C) and contrast-enhanced sagittal images (C,D) depict asubcapsular and perinephric left renal hematoma. Note the thickened perirenal bridgingsepta (small arrows) serving as conduit for the spread of fluid to the retrorenal plane andto the anterior renal fascia (open arrow).


33/37

Page 33 of 37

Fig. 16: Perirenal abscess in a 82-year-old man. Contrast-enhanced axial CT scan (A-C) and non-contrast-enhanced sagittal CT images (D,E) show a large collection withthickened enhancing wall that distends the perirenal space and extends into the psoas

compartment (solid arrows). Note the thickened anterior renal fascia (open arrow) andthe involvement of the posterior pararenal space (orange arrowhead).


34/37

Page 34 of 37

Fig. 17: Extraperitoneal air in a 83-year-old woman with a iatrogenic perforation of thesigmoid. Axial CT scan obtained without intravenous contrast material (A-D) depicts gaswithin the presacral space (red arrow) and within the perirectal space (yellow arrow)dissecting into the prevesical space (green arrow). Cephalad extension of the gasthrough the combined interfascial plane is demonstrated (C, circle and line; D). Thepneumoretroperitoneum penetrates into the perirenal space and into the retromesentericinterfascial plane (D, blue arrow). Note the presence of gas in the posterior pararenalspace and in the extraperitoneal anterolateral abdominal wall (white arrow).


35/37

Page 35 of 37

Fig. 18: 77-year-old woman with a retroperitoneal warfarin-induced hematoma. Axial CTscan obtained with intravenous contrast material (A-F) depicts an extensive hematomaalong the psoas compartment (yellow asterisks), that extends to the posterior renalspace and a large hematoma in the anterior pararenal space (purple asterisks). Note thepresence of hydronephrosis caused by the compression of the perirenal space (openarrow). Thickened bridging septa are seen providing a conduit for the spread of fluid intothe perirenal space (small arrows).


36/37

Page 36 of 37

Conclusion

The introduction of cross-sectional imaging was essential to understand and to study theextraperitoneal space anatomy and the extent of extraperitoneal disease.

The recognition of the anatomic relationships of the extraperitoneal space is important toaccurate CT diagnosis and analysis of extraperitoneal pathologic processes.

Personal information

Mariana Horta

Department of Radiology

Centro Hospitalar Lisboa Ocidental

Estrada do Forte do Alto do Duque 1449-005 Lisboa

Portugal

References

1. Gore RM, Balfe DM, Aizenstein RI, Silverman PM. The great escape:interfascial decompression planes of the retroperitoneum. AJR Am JRoentgenol. 2000 Aug;175(2):363-70.

2. Meyers M. The Extraperitoneal Spaces: Normal and Pathologic Anatomy. In:Dynamic Radiology of the Abdomen: Normal and Pathologic Anatomy, 6 th

EditioN. Springer-Verlag New York. 2005.3. Korobkin M, Silverman PM, Quint LE, Francis IR.CT of the extraperitoneal

space: normal anatomy and fluid collections. AJR Am J Roentgenol. 1992Nov;159(5):933-42.

4. Tirkes T, Sandrasegran K, Patel A, et al. Peritoneal and RetroperitonealAnatomy and Its Relevance for Cross-Sectional Imaging. RadioGraphics2012; 32,437-451.

5. Lee SL, Ku YM, Rha SE.Comprehensive reviews of the interfascial plane ofthe retroperitoneum: normal anatomy and pathologic entities. Emerg Radiol.2010 Jan;17(1):3-11. doi: 10.1007/s10140-009-0809-7. Epub 2009 Apr 28.


37/37

6. Thornton FJ, Kandiah SS, Monkhouse WS, Lee MJ. Helical CT evaluation ofthe perirenal space and its boundaries: a cadaveric study. Radiology. 2001Mar;218(3):659-63.

7. Mindell HJ, Mastromatteo JF, Dickey KW, et al. Anatomic communicationsbetween the three retroperitoneal spaces: determination by CT-guidedinjections of contrast material in cadavers. AJR Am J Roentgenol. 1995May;164(5):1173-8.

8. Kneeland JB, Auh YH, Rubenstein WA, et al. Perirenal spaces: CT evidencefor communication across the midline. Radiology. 1987 Sep;164(3):657-64.

9. Lim JH, Kim B, Auh YH. Anatomical communications of the perirenal space.Br J Radiol. 1998 Apr;71(844):450-6

10. Raptopoulos V, Lei QF, Touliopoulos P, Vrachliotis TG, et al. Why perirenaldisease does not extend into the pelvis: the importance of closure of thecone of the renal fasciae. AJR Am J Roentgenol. 1995 May;16 4(5):1179-84.

11. Burkill G J C, Healy J C. Anatomy of the retroperitoneum. Imaging (2000)12,10-20

12. Aizenstein RI, Wilbur AC, O'Neil HK. Interfascial and perinephric pathwaysin the spread of retroperitoneal disease: refined concepts based on CT

observations. AJR Am J Roentgenol. 1997 Mar;168(3):639-43.13. Rajiah P, Sinha R, Cuevas C, Dubinsky TJ, Bush WH Jr, Kolokythas O.Imaging of uncommon retroperitoneal masses. Radiographics. 2011 Jul-Aug;31(4):949-76.

14. Molmenti EP, Balfe DM, Kanterman RY, Anatomy of the retroperitoneum:observations of the distribution of pathologic fluid collections. Radiology.1996 Jul;200(1):95-103.

15. Rakita D, Newatia A, Hines JJ, et al. Spectrum of CT findings in rupture andimpending rupture of abdominal aortic aneurysms. Radiographics. 2007Mar-Apr;27(2):497-507.

16. Westphalen A, Yeh B, Qayyum A et al. Differential diagnosis of perinephricmasses on CT and MRI. AJR Am J Roentgenol. 2004 Dec;183(6):1697-702.

17. Vilaa A, Reis A, Vidal I. The anatomical compartments and theirconnections as demonstrated by ectopic air. Insights Imaging. 2013December; 4(6): 759-772.

18. Daliakopoulos SI, Bairaktaris A, Papadimitriou D, Pappas P. Giganticretroperitoneal hematoma as a complication of anticoagulation therapy withheparin in therapeutic doses: a case report. J Med Case Rep. 2008 May17;2:162

19. Furlan A, Fakhran S, Federle MP. Spontaneous abdominal hemorrhage:causes, CT findings, and clinical implications.AJR . 2009 Oct;193(4):1077-87.
http://www.ncbi.nlm.nih.gov/pubmed/19770332http://www.ncbi.nlm.nih.gov/pubmed/19770332

retropertioneo

Documents