Dr. Shaurya Agarwal presented on the peritoneal cavity. Key points included: 1. The peritoneal cavity is lined by the serous membrane called the peritoneum and is divided into compartments by peritoneal reflections. 2. Cross-sectional imaging such as CT is useful for evaluating the peritoneal spaces and reflections. MRI also provides good visualization. 3. There are many potential spaces within the peritoneal cavity where fluid, abscesses or metastases can accumulate based on anatomical boundaries. 4. A variety of cystic lesions can involve the peritoneal cavity including mucinous carcinomatosis, pseudomyxoma peritonei, cystic mesothelioma, mesent

1. PRESENTER
DR. SHAURYA AGARWAL
1st year Post graduate student
MODERATOR:,
PROF(DR) PARUL DUTTA,MD DMRD
Prof and Head of Department
Department of Radiology,GMCH

2.  Thin serous membrane that
lines the walls of the
abdominal and pelvic
cavities and cover the
organs within these cavities
 Also called as serosa.

3.  Plain radiography has been superseded by
cross-sectional imaging techniques
 Ultrasound is widely used to detect
intraperitoneal collections, but is limited by
bowel gas and body habitus

4. Contrast-enhanced CT (with or without oral contrast
medium) is the method of choice to evaluate the
peritoneal spaces, reflections and their contents.
MRI also provides good visualization of the
peritoneal spaces and reflections

6.  PET Imaging
 The use of FDG PET has been used to
demonstrate diffuse metastatic disease by the
increase uptake of FDG-18 in which shows
excellent correlation with CT

7. Larger part – Greater Sac
Smaller part – Lesser Sac
Communication-
 Epiploic Foramen
 Small pockets or recesses

8.  Peritoneal cavity is subdivided by peritoneal reflections into
multiple compartments
 provides the anatomical basis for understanding the
dynamic flow of intraperitoneal fluid, localization of ascitis ,
abscess and seeded metastasis.

9. PERITONEAL
CAVITY
SCS
R- SCS
R- PERI HEP
SPACE
SUB HEPATIC
SPACE
R- SUBPHRENIC
SPACE
LESSER SAC
SUP RECESS
INF RECESS
SPLEENIC RECESS
L- SCS
L- PERI HEP SPACE
ANTERIOR
POSTERIOR
L- SUBPHRENIC
SPACE
ANTERIOR
POSTERIOR
OR
PERISPLENIC
SPACE
ICS
R & L ICS
R & L PARACOLIC
GUTTERS

10.  Divided into –Rt subphrenic
and Rt subhepatic space
 Right subphrenic space;-
(Rt anterior space)
Extends over the
diaphragmatic surface of the
Rt lobe of liver
Limited by ;-
On left side ---by falciform
ligament
Posteriomedially--by the Rt
coronary ligament and the
triangular ligament.

11.  Right subhepatic space (hepatorenal
pouch / Morrison's pouch)
 Boundaries –
Anteriorly—the inferior surface of right
lobe of liver / the GB
Posteriorly— Right suprarenal gland / the
Right kidney /second part of duodenum.
Superiorly—inferior layer of the coronary
ligament
Inferiorly---- opens into general peritoneal
cavity

12.  Large recess of peritoneal cavity
behind the stomach, lesser
omentum and the caudate lobe of
liver
Boundaries –
 Anterior wall— the lesser
omentum/caudate lobe of liver/the
stomach
 Posterior wall— structure forming
stomach bed
 Upper border— caudate lobe of
liver.
 Lower border— continuation
between 2nd and 3rd layers of
greater omentum and its lower
margin.

14.  The right border-
reflection of peritoneum
from the diaphragm to
the right margin of the
caudate lobe / the floor
of epiploic foramen /
reflection of peritoneum
from the head and neck
of pancreas.
 The left border— by
gastrophrenic ligament/
the gastrosplenic
ligament and linorenal
ligament.

15.  Subdivision of the lesser
sac—peritoneal fold arising
from left gastric artery divides
the lesser sac into –superior
recess and inferior recess
 Superior recess-- lies
behind the lesser omentum
and the liver communicate
with the right subhepatic
space via foramen of
Winslow
 Inferior recess --lies behind
the stomach and within the
greater omentum.
 Splenic recess

16.  2.5cm vertical slit.
 BOUNDARIES
 Anterior: free margin of
lesser omentum, containing
(hepatic artery, bile duct and
portal vein)
 Posterior: peritoneum
covering IVC.
 Superior: Caudate process of
the caudate lobe of the liver.
 Inferior: part of duodenum.

17.  Divided into- Lt perihepatic and Lt
subphrenic space
 Left anterior perihepatic space ;-
Anteriorly –diaphragm
posteriorly –liver surface
On right –falciform ligament
 Left posterior perihepatic
space(gastrohepatic recess) ;- follows
the posterior margin of the lateral
segment of the left lobe of liver
Closely related with—lesser curvature of
stomach and seperated by superior
recess of lesser sac by lesser omentum

18.  Left anterior subphrenic space ;-
Space between the anterior wall of
the stomach and the left
hemidiaphragm
Communicating with left anterior
perihepatic space.
 Left posterior subphrenic space
(perisplenic space) ;-posterior
extension
Covers ---the superior and
inferolateral surface of the spleen
superiorly –bounded by
gastrosplenic ligament
Inferiorly--bounded by phrenico-colic
ligament

19.  Boundaries- Superiorly-transverse
mesocolon
Inferiorly- pelvic rim
 Contains - Infracolic space
Paracolic gutter
 Infracolic space— right / left
 Right infracolic space— between
ascending colon and the mesentery
below the transverse mesocolon.
 Left infracolic space-- between the
descending colon and the
mesentery.

20.  Located alongside the lateral borders
of the ascending and descending
colon.
 Right paracolic gutter---
communicates freely into hepatorenal
pouch at its upper end and with pelvic
space inferiorly.
 Left paracolic gutter---opens freely
into the pelvis in its lower end .
Above it is seperated from the spleen
and the lienorenal space by the
phrenicocolic ligament.

21.  In men, there is only one potential space for fluid collection
posterior to the bladder, the rectovesical pouch.
 In women there are two potential spaces: posterior to the
bladder, the uterovesical pouch and, posterior to the uterus,
the deeper rectouterine pouch (of Douglas).
 The layers of peritoneum on the anterior and posterior
surfaces of the uterus are reflected laterally to the pelvic side
walls as the broad ligaments, containing the fallopian tubes.

22. The urinary bladder subdivides
the pelvis into right and left
paravesical space
Perirectal spaces are lateral
to the rectosigmoid

23.  The retroperitoneum is bounded;-
Anteriorly - parietal peritoneum
Medially- fascia covering the
psoas
Posteriorly--quadratus lumborum
Laterally - transversalis fascia.

24. Anterior pararenal space;-
 Anteriorly - the posterior
peritoneum,
 Posteriorly - the anterior renal
fascia (Gerota’s),
 Laterally - lateral conal fascia
 Contains;- ascending and
descending colon, duodenum
and pancreas
 Perirenal space;-
Anteriorly - anterior renal fascia
(Gerota's)
Posteriorly - posterior renal
fascia (Zuckerkandl's)
Contains;- Lt and Rt kidneys
,adrenals and great vessels.

25.  Posterior
pararenal
space;-
Anteriorly -
posterior
renal fascia
(Zuckerkandl
's)/ lateral
conal fascia
Posteriorly -
Transversalis
fascia.

26.  Folds of peritoneum which suspends abdominal organs
from abdominal wall or connects each other.
Peritoneal
reflection
omentum
greater
omentum
gastrosplenic
lig
Gastrocolic
lig
Gastrophrenic
lig
Lesser
omentum
gastrohepatic
Gastroduodenal
lig
Mesenteries
Mesentery
proper
Transverse
mesocolon
sigmoid
Mesocolon
Ligaments

27. PERITONEAL
DERIVATIVES
FROM TO
LIGAMENTS SOLID VISCERA ANTERIOR ABDOMINAL
WALL
OMENTUM STOMACH ANOTHER VISCUS
MESENTRY PARTS OF INTENSTINE POSTERIOR ABDOMINAL
WALL
FALCIFORM LIGAMENT LIVER DIAPHRAGM AND
ANTERIOR ABDOMINAL
WALL

30.  Fold of peritoneum which hanges down from
the greater curvature of the stomach
 Made of four layers of peritoneum.
 Attachment-- Anterior two layers
descends from greater curvature of
stomach then fold upon themselves
forms the posterior two layers
which ascends to the transverse colon
Content
- right and left Gastroepiploic vessels
- fat.

31. The Greater omentum is
subdivided into:
 Gastrocolic ligament: the
largest component.
 Gastrosplenic ligament: up
to the hilus of the spleen .
 Gastrophrenic ligament.

32.  Fold of peritoneum which
extends from the lesser
curvature of the stomach and
the first 2 cm of duodenum to
the liver.
 Attachment-
Inferiorly---lesser curvature of
stomach and first 2cm of
duodenum.
Superiorly- liver, as inverted
” L” pattern attachment,
Vertical limb-- fissure for lig.
Venosum
Horizontal limb- margins of the
Porta hepatis.

33. Parts of lesser omentum ;-
 Medial Gastrohepatic
ligament- portion of lesser
omentum between the
stomach and liver.
 Lateral Hepatoduodenal
ligament- between duodenum
and liver.

34.  Broad fan shaped fold of
peritoneum which suspends the
coils of intestine from the
posterior abdominal wall.
 The root of the mesentry extends
obliquely downwards from
duodenojejunal flexure (left L2),
ending at the ileocecal junction
near the upper border of the right
sacroiliac joint.
 Crosses- third part of duodenum
/abdominal aorta / inferior vena
cava / right ureter / right psoas
muscle.

35.  suspends the transverse colon
from the posterior abdominal wall.
 Extends from anterior surface of
head and the anterior border of
body of pancreas to transverse
colon.
 Contents---Middle Colic vessel
and nerves/Lymph nodes and
lymphatics

36.  Triangular fold of peritoneum which
suspends the sigmoid colon
Root is shape like inverted ” V”.
Attachments;-
Apex- lies over the left ureter at the
termination of the left CIA.
Left limb of ‘V’—along the upper half of
left EIA
Right limb of V—posterior pelvic wall at
the level of S3.
• Contents
• Sigmoid and superior rectal vessels
• Nerves and lymphatics

37.  Wide fold of peritoneum that
connects the sides of the uterus to
the walls and floor of the pelvis
Subcomponents
 Mesometrium-largest portion of the
broad ligament
 Mesosalphinx
 Mesovarium-the part connecting
anterior surface of the ovary to the
broad ligament

38.  The movement of fluid in the circulatory pathway
is produced by the respiratory movement and
peristalsis.
 There are watershed regions in the peritoneal
cavity that are areas of fluid stasis:
-ileocolic region
-Root of the sigmoid mesentery
-Pouch of Douglas
90% of peritoneal fluid is cleared at the subphrenic
space by the submesothelial lymphatics,Which
are connected with lymphatics at the other side
of the diaphragm

39. Peritoneal circulation

40. 1- Movement of viscera
- Free movement of abdominal viscera
2- Protect of viscera :
 - provide cellular & humoral immunological
defence
 - greater omentum has the power to move
towards site of infection (policeman of abdomen )
3- Absorption : -
 The greater absorptive power of the subphrenic
area due to large surface area and respiratory
movement

43.  Mucinous Carcinomatosis
 Pseudomyxoma peritonei
 Cystic Mesothelioma
 Mesenteric cyst - Lymphangioma
 Pancreatic psuedocyst
 Tuberculosis
 UNCOMMON LESIONS
 Enteric Duplication Cyst
 Nonpancreatic Pseudocyst
 Enteric cyst and mesothelial cyst
 Peritoneal Inclusion Cyst
 Echinococcal Cyst
 Cystic teratoma

44.  Mucinous carcinomatosis is the most common
cystic tumor to affect the peritoneal cavity.
 Usually these metastases arise from mucinous
carcinomas of the ovary or of the gastrointestinal
tract (stomach, colon, pancreas).

45. 40-year-old man who complained of
progressive abdominal pain, nausea,
and vomiting

46.  Pseudomyxoma peritonei is the result of a mucinous
adenocarcinoma of the appendix, which presents as
a mucocele and spreads to the peritoneal cavity.
 A typical feature of pseudomyxoma peritonei is
scalloped indentation of the surface of the liver and
spleen.
 Unlike peritoneal metastases, there are no tumor
nodules however there may be some calcification

47. complex echogenic fluid with
scalloping of the lower border

48. scalloping

49.  Lymphangioma is a benign lesion of vascular
origin.
 Lymphangioma has enhancing septa.
 Unlike in cystic peritoneal metastases, ascites is
not a feature of lymphangioma.
 When we see a septated cystic lesion without
ascites the most likely diagnosis is a
lymphangioma.

50. multilocular masses containing complex
fluid
a low-density mass lesion in the
transverse mesocolon. Transverse
colon appears to be floating in the
mass.

51.  Pseudocysts are
round or oval
collections of
pancreatic fluid
confined by a
fibrous wall or
capsule.
 They usually
evolve from an
acute fluid
collection following
acute pancreatitis. Gas is seen in the pseudocyst

52.  Nonpancreatic pseudocyst is a residual of an old
hematoma or infection.
 Most of these patients have a history of prior
abdominal trauma.
 Often there is a thickened wall and there can be
some debris within the lesion.

53. probably an old mesenteric hematoma Thickened wall

54.  Also called Multilocular peritoneal inclusion
cyst or Benign cystic mesothelioma.
 It occurs in premenopausal women with prior
gynaecological surgery or infection
 The imaging features includes-
 Multicystic pelvic mass
 Enhancing septa
 May extend into upper abdomen.

55. Transvaginal ultrasound

56. CT usually shows multiple cystic
masses with thin walls that donot
produce a mass effect on adjacent
structures
Adhesions to the uterus and
entrapment of the ovary

57.  TB can produce very thick ascites, that can be
loculated in distribution,because of this, it can
simulate a cystic lesion.
 Usually there is accompanying abnormality of the
terminal ileum and lymphadenopathy.
 The lymph nodes most often are of low
attenuation (caseated).

58.  Enteric duplication cyst is a cyst with a wall that
has all three layers of the bowel wall, i.e. mucosa,
submucosa and muscularis propria.
 They may occur anywhere in the mesentery, so
either adjacent to or away from the bowel

59.  Congenital cystic lesions of the vagina include
müllerian and Gartner’s duct and Noncongenital
include retention cysts of the vestibulum and
epidermal inclusion cysts
 Bartholin’s Cysts -Bartholin’s cysts are the most
common vulva cyst arising from the Bartholin’s
glands.Lesions are T2 hyperintense, with variable
signal on T1 depending on the proteinaceous
content.

60.  Benign Cystic Lesions of the ovary include
physiologic Cysts,hemmorhagic
cyst,cystadenoma,Peritoneal inclusion cyst and
paraovarian cyst
 Para ovarian cyst- arises from mesonephric(wolffian
)or paramesonephric cyst(Mullerian)structure.The
Hydatid of morgagni is the most common.
 On USG they are round to oval ,anechoic and
indistinguishable from simple ovarian cyst except that
the ovary is seen separately.The cyst may undergo
torsion or rupture

61.  Typically CT images
demonstrate fat
, calcification and tufts of
hair
 Whenever the size exceeds
10 cm or soft tissue plugs
and cauliflower appearance
with irregular borders are
seen, malignancy be
suspected .

62.  Peritoneal metastases
 Lymphoma
 Metastatis from carcinoid and adenocarcinoma
 Gastrointestinal Stromal Tumor – GIST
 Inflammatory Pseudotumor
 Mesenteric fibromatosis – Desmoid
 Sclerosing Mesenteritis
 UNCOMMON LESIONS
 Malignant mesothelioma
 Primary Peritoneal Serous Carcinoma
 Desmoplastic Small Round Cell Tumor
 Retro-peritoneal liposarcoma

63. Peritoneal metastases are the most
common peritoneal solid masses.
 Gastrointestinal and ovarian cancers are the
most common etiologies.

64. Usually there are omental metastases, i.e. omental
cake and ascites.

65. omental caking

66. Peritoneal carcinomatosis in a 30-year-
old woman with malignant melanoma
Metastatic ovarian carcinoma

67. Mesenteric Adenitis
-Benign inflammation of the mesenteric lymph nodes
 Primary mesenteric adenitis consists of right-sided mesenteric
adenopathy without a concomitant, identifiable acute inflammatory
process, with or without wall thickening of the terminal ileum
 Secondary mesenteric adenitis is described as mesenteric
adenopathy (usually right-sided) associated with an identifiable
intra-abdominal inflammatory process such as Crohn's disease,
infectious colitis, ulcerative colitis, or diverticulitis.

68. Primary Mesenteric Adenitis

69. Local lymphadenopathy due to appendicitis

70. Tuberculous lymphadenopathy

71.  In HIV ,MAC show conglomerate adenopathy in the
mesentery. More discrete nodes are in the RLQ .
vascular engorgement and perivascular edema

72.  NHL is the most common cause of lymphadenopathy.
 Three patterns of involvement include the mesenteric
root or scattered throughout the peripheral
mesentery, or mixed root-peripheral pattern
 The CT attenuation at diagnosis is very
homogeneous in most cases with minimal to no
enhancement.
 Heterogeneous attenuation is seen only in cases with
aggressive histology as a result of necrosis and
fibrosis.Calcification may occur

73. conglomerate mesenteric lymph nodes

74.  Carcinoid is a slow-growing neuroendocrine tumour
most commonly found in the small bowel.
 Less than 10% of patients will develop the carcinoid
syndrome
 Carcinoid shows metastatis to the mesentery, which
at times is easier to appreciate than the primary
tumor in the small bowel.
 There is associated bowel wall thickening due to
desmoplastic reaction.

75. spiculated soft tissue mass within the small bowel mesentry and calcifications
and soft tissue spiculations arising from the mass are pathognomic of
desmoplastic reaction

76.  Primary colonic manifests on CT as thickening
and infiltration of the pericolic fat or an ill-defined
soft tissue mass extending into the fat.
circumferential thickening

77.  Primary small bowel tumors can extend into the
mesentery and the typical example of that is the
GIST.
 On CT they are of mixed density due to necrosis
and hemorrhage and they tend to be well
vascularized, so they will enhance.

78. heterogeneously enhancing mass in
the greater omentum due to necrosis
and hemorrhage

79.  It is a chronic inflammatory
disorder of uncertain
etiology
 This disease can affect
lung, orbit and mesentery.
 Sequale of occult infection,
minor trauma, or prior
surgery

80.  Mesenteric fibromatosis or desmoid is a benign
proliferative process that is locally aggressive and
can recur, but it does not metastasize.
 The small bowel mesentery is the most common
site.
 13% of patients have familial adenomatous
polyposis (FAP).

81. 
a well circumscribed soft tissue mass lesion

82.  Uncommon condition of unknown etiology characterized by
chronic inflammation involving the adipose tissue of the
bowel mesentery at its root.
 Can be categorized into three subgroups
 Mesenteric panniculitis is characterized by chronic
inflammation
 Mesenteric lipodystrophy by fat necrosis
 Retractile mesenteritis by fibrosis

83. On CT
-a well-circumscribed or infiltrating margins soft tissue mass with
variable enhancement and central calcification
-Larger masses may demonstrate cystic features, suggesting
necrosis and enlarged nodes may be found
-Linear bands of fibrosis may radiate from the mass affecting the
small bowel by retraction and shortening of mesentery rather than
by direct invasion

85. Differential Diagnosis
 Lymphoma:
-does not usually calcify unless previously treated
-does not often cause bowel ischemia
-more likely to demonstrate discrete to conglomerated
enlarged nodes
 Small bowel carcinoid
-focal small bowel mural thickening or mass favors the
diagnosis of carcinoid
 Whipple’s disease, Weber-Christian disease ,mesenteric
fibromatosis, inflammatory pseudotumor, and extrapleural
solitary fibrous tumor

86. Mesenteric panniculitis- diffusely increased attenuation of the central small
bowel mesenteric fat and presence of mesentric nodes.

87. Fat necrosis in the transverse mesocolon
Idiopathic disorder characterised by chronic non-specific inflammation
involving the adipose tissue of the bowel mesentery –degeneration of fat

88.  Here fibrosis predominates and is confined to the
mesentery, and there are no abnormalities of the
intestines or vessels
 On CT
-The mesentery is of soft tissue density that can
be masslike and calcifications
-The bowel is retracted posteriorly
- transmural thickening of the colon with narrowing
and rigidity of the colon with thumbprinting
appearence.

89. Thickening of the
neurovascular bundle
Diffrentiated
by tumor
implants in
the
mesentery

90.  Epiploic appendagitis is a rare self limiting
inflammatory/ischaemic process involving
the appendix epiploica of the colon.
 MC location –
rectosigmoid junction: 57%
ileocecal region: 26%

91. ovoid, noncompressible,
hyperechoic mass, having
a mass effect without
bowel wall thickening
paracolonic ovoid fatty
mass with surrounding
inflammatory change

92.  Malignant Mesothelioma
 Primary Peritoneal serous carcinoma
 Desmoplastic small round cell tumor

93.  Suggestive features are a sheet-like peritoneal
thickening and absence of lymphadenopathy.
 Just like pleural mesothelioma, it is associated with
asbestos exposure.
 In advanced cases we will see encasement of the
intra-peritoneal structures

94. sheet-like thickening of the
peritoneum
Encasement of the bowel and the liver

95.  This tumor occurs exclusively in women and is identical to
malignant ovarian surface epithelial tumors.
 Consider this diagnosis when:
 Ovaries are normal or
 Involvement of extraovarian sites is greater than that of
the ovarian surface or
 If ovaries are involved, yet disease is confined to the
surface epithelium

96. solid mass involving the right aspect of
the omentum
prominent omental vessel

97.  It occurs primarily in young men with a mean age of
19 years.
 It is a very aggressive tumor with a poor prognosis
This tumor begins as
a dominant mass and
then multiple masses
occur within the
peritoneum .

98. Liposarcoma.
 well-differentiated, myxoid, pleomorphic, and
round cell types.
 well-differentiated type had a similar appearance
to lipoma and exhibited a low density similar to
subcutaneous fat
 The myxoid type had attenuation less than muscle
on CT .
 The pleomorphic and round cell types had density
and attenuation similar to muscle on CT

99.  Features that suggest malignancy to
distinguish lipoma from well-differentiated
liposarcoma includes-
 Older patient age
 Large lesion size
 presence of thick septa
 and presence of nodular or nonadipose-like
areas with a decreased percentage of fat
composition

100. low in density
pseudomyxomatous
invasion
compressing loops
of the small bowel
low-density tumor
appears like fluid

101.  Peritonitis
 CT findings consist of thickening and nodularity
of the peritoneum, omentum and mesentery,
increased density of the mesenteric fat, and
ascites

102.  Tuberculous peritonitis
 Types of tubercular peritonitis
 wet type: (commonest,90%) exudative high
attenuation ascites (HU 20-45), which may be
free or loculated; high attenuation of the ascites
is thought to be due to high protein and cellular
content
 Dry type: caseous mesenteric
lymphadenopathy and fibrous adhesions;
thickened, ‘cake-like’ omentum.
 Fibrotic type: omental ‘cake-like’ mass with
fixed bowel loops; matted loops and mesentery
with loculated ascites.
Matted bowel loops in
ascites

103. Large abscess with
echogenic debris
and air foci
Large abscess with internal
septation and debris

104. Multiple mesenteric abscesses

105.  The peritoneal reflections suspends the intra-abdominal
organs
 peritoneal cavity and intercommunicating spaces helps in
understanding of pathologic processes involving the
peritoneal cavity .
 Ligaments, omenta, and mesenteries can serve as routes
of disease spread within the peritoneal cavity.
 Many inflammatory and malignant processes cause
abdominal adenopathy .
 CT has become the primary modality for its detection and
the effectiveness of therapy with serial CT.