The Pancreas
The pancreas is a gland
organ in the digestive and
endocrine system.It’s both
endocrine organ producing
several important hormones,
including insulin, glucagons,
& somatostatin, as well as
an exocrine organ, secreting
pancreatic juice containing
digestive enzymes that pass
to the small intestine. These
enzymes help in the further
breakdown of the
carbohydrates, fat &protein.
Pancreatic parts
It is long and irregularly prismatic in shape; its right
extremity, being broad, and is lodged within the curve of
the duodenum & called the head with lower prolongation
called the uncinate process , the head is connected to
the main portion of the organ, or body, by a slight
constriction, the neck; while its left extremity gradually
tapers to form the tail. It is situated transversely across
the posterior wall of the abdomen, at the back of the
epigastrium and left hypochondrium.
Pancreatic ducts
The Major pancreatic duct,
or Duct of Wirsung joins
the common bile duct just
prior to the ampulla of Vater,
after which both ducts
perforate the medial side of
the second portion of the
duodenum at the major
duodenal papilla.
Accessory pancreatic duct
or the Duct of Santorini
opens into the duodenum
about 2.5 cm. above the
duodenal papilla. It receives
the ducts from the lower part
of the head,
What are the peritoneal coverings
of the pancreas ??
Pancreas is a Retroperitoneal organ!!!!
Blood vessels related to pancreas
Aorta & IVC lie behind the
neck & body of the
pancreas,
Both superior mesenteric
artery and vein pass
anteriorly to the uncinate
process .
Splenic vein moves at the
at the posterior aspect of
the pancreas & unites with
superior mesenteric vein
to form the portal vein
which lie behind the neck
of pancreas.
The splenic artery lie at
the upper border of the
pancreas.
Histology of the pancreas
Under a microscope, stained
sections of the pancreas
reveal two different types of
parenchymal tissue Lightly
staining clusters of cells are
called islets of langerhans,
which produce hormones
(e.g Insulin) Darker staining
cells form acini connected to
ducts. Acinar cells belong
to the exocrine function and
secrete digestive enzymes
into the gut via a system of
ducts.
Imaging Modalities of pancreas
imaging of the pancreas can be divided into two categories
Indirect imaging
involves non-invasive
radiologic techniques
including:
 plain film,
 US,
 CT,
 MRI,
 MRCP.
Direct imaging
involves invasive
radiologic procedures,
which include:
 ERCP
 operative
pancreatography.
Plain Film
The pancreas is not directly visualized on plain
films of the abdomen. Calcifications in the
pancreatic region or biliary lithiasis can sometimes
be demonstrated. The presence of adynamic ileus
of the duodenum& the proximal small bowel loops
(sentinel loop) can be an important sign in acute
disorders.
Ultrasonography (US)
How can you identify the pancreas at US?
The body of the pancreas is usually found anterior to the
splenic vein. In some patients however, body habitus
and bowel gas may limit complete visualization.
Computed Tomography (CT)
is used to evaluate the differences in the density, texture, and contour
of the pancreas. Secondary signs such as dilation of the bile or
pancreatic duct, or changes in the peripancreatic fat density, are also
used in the determination of a diagnosis. IV contrast enhancement is
also used, especially in analysis of pancreatic masses.
During CT examination of the pancreas thin pancreatic cuts are needed
(3-5mm) to accurately identify pancreatic lesions.
Magnetic resonance imaging
(MRI)
MRI shows soft tissue with super clarity, while avoiding the
potential risks of ionizing radiation. Densities in an MR
image are based on tissue water and lipid content (while
CT densities are based on varying absorption of X-rays by
different tissue).
Magnetic resonance
cholangiopancreatography (MRCP)
MRCP is a non-invasive technique that delineates the
pancreatic and biliary ductal systems, while providing
projectional and cross sectional images of the
ducts. MRCP does not require administration of
intravenous contrast material; it is based on T2-weighted
images, which depict static fluid (including bile and
pancreatic secretions), with a higher signal
intensity. MRCP also avoids the invasive complications of
ERCP. With the recent improvements in MRCP, it is
superceding ERCP for many of its diagnostic
indications. MRCP is inferior to ERCP in several respects
however. The spatial resolution of MRCP is lower than
that of ERCP. Furthermore, ascites or fluid collections in
the upper abdomen can interfere with the visualization of
the pancreatic and biliary ducts.
Endoscopic Retrograde
Cholangiopancreatography (ERCP)
ERCP is a combined endoscopic and radiographic
procedure that images the biliary and pancreatic
ducts. ERCP is performed with a side-viewing
duodenoscope which has an instrumentation channel
that allows for the insertion of the cannulation catheter
into the major or minor duodenal papilla. A water-soluble
contrast agent (60 % iodine) is injected into the ductal
system using fluoroscopy for imaging. It is important to
obtain adequate ductal filling without over-distending the
system. (During interventional procedures, a guide-wire
can be inserted through the cannulation catheter, for
subsequent insertion of additional instruments like
papillotomes, drainage devices, cytology brush,
etc.) Althought ERCP is an important diagnostic tool in
the evaluation of patients with suspected biliary and
pancreatic disorders,MRCP is superceding ERCP for
some of its indications.
ERCP Indications
>Pancreatic Diseases
--Acute gallstone
pancreatitis
--Recurrent acute
pancreatitis
--Chronic pancreatitis
--Pancreatic
pseudocyst, abcess
--Pancreatic tumors
ERCP Pancreatography:
The pancreatic ducts are filled with contrast (under
fluoroscopy) until the tail and the first order side branches
are visualized. Since the pancreatic duct empties relatively
quickly, images are acquired while the endoscope is in
situ. A normal pancreatogram shows the main pancreatic
duct to be in the shape of a pistol. The mean diameter of
the duct is 4mm at its distal end, which decreases towards
the tail. (This diameter increases significantly with
age.) Normal ducts have a smooth lining, with small,
regular side-branches. Interpretation of a pancreatogram
may be complicated by different congenital ductal
variations.
operative pancreatography
Developmental anatomy, normal variants&
congenital anomalies of the pancreas
The pancreas develops from dorsal and ventral diverticula that buds from the
primitive foregut. These 2 buds fuse after the rotation of the duodenum
adjoins the two structures. The ventral bud develops from the hepatic duct,
and forms the uncinate process and the posterior/inferior head of the
pancreas. The dorsal bud develops directly from the foregut, forming the
anterior head, body and tail of the pancreas. The distal duct system of the
dorsal bud joins with that of the ventral bud to form the main pancreatic duct
(of Wirsung), which joins with the common bile duct at the level of the ampulla
of Vater. The distal duct system of the dorsal bud may persist as the
accessory pancreatic duct (of Santorini), and empties into the duodenum at the
minor duodenal papilla. The "normal" short axis measurement of the pancreas
is 2.5 cm at the head, and 1.5 cm at the tail; there are normal variations.
In general, the pancreas decreases with size with age.
Pancreas Divisum
Pancreas divisum represents an anomaly of the fusion of the two pancreatic
buds and their respective ducts. It is the most common pancreatic ductal
system anomaly; it is seen in 4-6% of ERCP patients. The duct of ventral bud
does not fuse with the duct system of the dorsal pancreatic bud; it joins the
common bile duct at the level of the ampulla of Vater. The dorsal duct of
pancreas, which drains the anterior head, body and tail, terminates more
cephalad, at the minor duodenal papilla. The narrow size of the os in the minor
papilla may result in inefficient drainage of pancreatic secretions. It is widely
believed that pancreas divisum predisposes to chronic pancreatitis
Pancreas Divisum
ERCP is the main diagnostic modality
Cannulation of the major duodenal
papilla and injection of contrast
material reveals only a short segment
of the main pancreatic duct
Cannulation of the minor duodenal
papilla and opacification of the dorsal
pancreatic duct
Annular Pancreas
Annular pancreas results from a band of pancreatic
parenchyma that encircles a section of the second part of
the duodenum. The embryologic anomaly is secondary to
the malrotation of the ventral bud, which wraps around the
duodenum to fuse with the dorsal bud. This malformation
can be isolated or can be accompanied by a digestive
tract malrotation or atresia. Its frequency is also increased
by Trisomy 21.
Annular Pancreas
The clinical consequences of annular pancreas depend on the degree
of duodenal obstruction. In cases of complete obstruction, the
diagnosis is readily evident in the neonate. Plain films reveal two
asymmetrical air-fluid levels, one gastric, the other duodenal, with little
distal bowel gas. This is the "double bubble" sign. The diagnosis can
be suggested by prenatal US, which would demonstrate the two
constant liquid-containing abdominal structures, possibly accompanied
by hydroamnios. This anomaly may present later, and into adulthood,
as partial duodenal obstruction or pancreatitis. The treatment of
significant obstruction is always surgical.
Common Variations in Ductal
Anatomy