Pancreas
Ali B Alhailiy
pancreas
The pancreas is a glandular organ in the digestive •
systemand endocrine system.
It is an endocrine gland producing several •
important hormones, including insulin, glucagon,
somatostatin, and pancreatic polypeptide which
circulate in the blood. The pancreas is also a
digestive organ, secreting pancreatic juice
containing digestive enzymes that assist digestion
and absorption of nutrients in the small intestine.
These enzymes help to further break down the
carbohydrates, proteins, and lipids .
Structure
• The pancreas is an endocrine organ that lies in
the abdomen, specifically the upper, left
abdomen. It is found behind the stomach,
with the head of the pancreas surrounded by
the duodenum. The pancreas is typically 5.759.5 cm long.
Structure
• Anatomically, the pancreas is divided into a head,
which rests within the concavity of the
duodenum,
• a body lying behind the base of the stomach,
• and a tail, which ends abutting the spleen.
• The neck of the pancreas lies between the body
and head, and is in front of the superior
mesenteric artery and vein.
• has two main ducts, the main pancreatic duct,
and the accesory pancreatic duct. These drain
enzymes through the Ampulla of Vater into the
duodenum.
anatomy
Anatomy
Anatomy in CT
Function
B - Exocrine
• The pancreas as an exocrine gland helps out the digestive system. It
secretes pancreatic fluid that contains digestive enzymes that pass
to the small intestine. These enzymes help to further break down
the carbohydrates, proteins and lipids (fats) .
• In humans, the secretory activity of the pancreas is regulated
directly via the effect of hormones in the blood on the islets of
Langerhans.
• The exocrine component of the pancreas, often called simply the
exocrine pancreas, is the portion of the pancreas that performs
exocrine functions. It has ducts that are arranged in clusters called
acini (singular acinus). Pancreatic secretions are secreted into the
lumen of the acinus, and then accumulate in intralobular ducts that
drain to the main pancreatic duct, which drains directly into the
duodenum.
• Control of the exocrine function of the pancreas is via the
hormones gastrin, cholecystokinin and secretin, which are
hormones secreted by cells in the stomach and duodenum, in
response to distension and/or food and which cause secretion of
pancreatic juices
Function
• The pancreas is a dual-function gland, having features
of both endocrine and exocrine glands.
A- Endocrine
• The part of the pancreas with endocrine function is
made up of approximately a million cell clusters. Four
main cell types exist in the islets .they can be classified
by their secretion:
• α (alpha) cells secrete glucagon (increase glucose in
blood), β (beta) cells secrete insulin (decrease glucose
in blood), Δ (delta) cells secrete somatostatin
(regulates/stops α and β cells) and PP cells, or gamma
cells, secrete pancreatic polypeptide.
• The islets of Langerhans play an imperative role in
glucose metabolism and regulation of blood glucose
concentration.
PATHOLOGY
• 1- Pancreatitis
• Pancreatitis is inflammation of the pancreas. There are two forms
of pancreatitis, which are different in causes and symptoms, and
require different treatment:
• Acute pancreatitis is a rapid-onset inflammation of the pancreas,
most frequently caused by alcoholism or gallstones.
• Chronic pancreatitis is a long-standing inflammation of the
pancreas.
• 2- Diabetes mellitus
• The pancreas is central in the pathophysiology of both major types
of diabetes mellitus. In type 1 diabetes mellitus, there is direct
damage to the endocrine pancreas that results in insufficient insulin
synthesis and secretion. Type 2 diabetes mellitus , which begins
with insulin resistance , is characterized by the ultimate failure of
pancreatic β cells to match insulin production with insulin demand.
• 3- Exocrine pancreatic insufficiency
• (EPI) is the inability to properly digest food due to a lack of digestive
enzymes made by the pancreas. EPI is found in humans afflicted
with cystic fibrosis. It is caused by a progressive loss of the
pancreatic cells that make digestive enzymes. Chronic pancreatitis is
the most common cause of EPI in humans..
• 4- Cystic fibrosis
• Cystic fibrosis, is a hereditary disease that affects the entire body,
causing progressive disability and early death. It is caused by a
mutation in the cystic fibrosis transmembrane conductance
regulator (CFTR) gene. The product of this gene helps create sweat,
digestive juices, and mucus. The name cystic fibrosis refers to the
characteristic 'fibrosis' (tissue scarring) and cyst formation within
the pancreas, causing irreversible damage, and often resulting in
painful inflammation (pancreatitis).
• 5- Cysts
• (CT scan) findings of cysts in the pancreas are
common, and often are benign.
• In a study of 2,832 patients without pancreatic
disease, 73 patients (2.6%) had cysts in the
pancreas.About 85% of these patients had a
single cyst. Cysts ranged in size from 2 to 38 mm
(mean, 8.9 mm). There was a strong correlation
between the presence of cysts and age.
6- pancreatic mass
A pancreatic mass is any undifferentiated •
growth detected in the pancreas, usually on
medical imaging.
Masses can be described based on their •
physical characteristics, as defined by imaging
studies, as solid (consisting of solid abnormal
tissue) or cystic (cavitie filled with mucus or
fluid such as pseudocysts,” .
correct diagnosis. •
Signs and symptoms
• A-The clinical history can often help establish the nature of
a tumor involving the pancreas. For example, a history of
alcoholism complicated by multiple episodes of pancreatitis
suggests the possibility of a pseudocyst, the leakage and
collection of pancreatic enzymes outside of the pancreas.
By contrast, patients with painless jaundice (an abnormal
yellowing of the skin and eyes often caused by blockage of
the bile ducts) are more likely to have a pancreatic cancer.
B- Blood tests can also point to the correct diagnosis.
Patients with pseudocysts often have associated
pancreatitis with elevated blood levels of the enzymes
amylase and lipase, while patients with pancreatic cancer
may have elevated levels of the cancer marker .
C-medical imaging
A number of different approaches can be used to visualize •
the pancreas. The most common include CT scan),
magnetic resonance imaging (MRI), positron emission
tomography (PET), endoscopic ultrasound (EUS), and
endoscopic retrograde pancreatography (ERCP). Each of
these different imaging approaches has its own strengths
and weaknesses.
CT scanning is a widely available and an excellent modality •
to image the pancreas.
MRI is a great method to visualize the pancreatic ducts, •
PET scanning can reveal the metabolic activity of a tumor.
ERCP can be used to visualize the duct system of the •
pancreas and stents (small tubes to re-establish the flow of
secretions such as bile) can be placed during the ERCP
procedure.
Papillary cystic and solid tumour of the
pancreas
Solid pseudopapillary tumor of
pancreas
Endoscopic retrograde
cholangiopancreatography (ERCP)
Endoscopic retrograde cholangiopancreatography •
(ERCP) is a technique that combines the use of
endoscopy and fluoroscopy to diagnose and treat
certain problems of the biliary or pancreatic ductal
systems.
Through the endoscope, the physician can see the •
inside of the stomach and duodenum, and inject
radiographic contrast into the ducts in the biliary tree
and pancreas so they can be seen on X-rays.
ERCP is used primarily to diagnose and treat conditions •
of the bile ducts and main pancreatic duct, including
gallstones, inflammatory strictures (scars), leaks (from
trauma and surgery), and cancer.
. ERCP can be performed for diagnostic and •
therapeutic reasons.
The development of safer and relatively non- •
invasive investigations such as magnetic
resonance cholangiopancreatographY (MRCP)
and endoscopic ultrasound has meant that
ERCP is now rarely performed without
therapeutic intent.
Magnetic resonance
cholangiopancreatography (MRCP)
(MRCP) is a relatively new MR imaging technique •
that is used for noninvasive work-up of patients
with pancreaticobiliary disease.
Recent studies have shown that MRCP is •
comparable with invasive (ERCP) for diagnosis of
extrahepatic bile duct and pancreatic duct
abnormalities such malignant obstruction of the
bile and pancreatic ducts, congenital anomalies
,and chronic pancreatitis . In some institutions,
MRCP is becoming the initial imaging tool for the
biliary system.
Technique
By using T2-weighted sequences, the signal of •
static or slow-moving fluid-filled structures such
as the bile and pancreatic ducts is greatly
increased.
The coronal plane is used to provide a •
cholangiographic display.
the axial plane is used to evaluate the pancreatic •
duct and distal common bile duct.
In addition, some institutions perform three- •
dimensional reconstruction by using a maximumintensity projection (MIP) algorithm on the thincollimation source images increased duct-tobackground contrast.
advantages of MRCP
indication for ERCP are unsuccessful ERCP and •
contraindication to ERCP .
Although ERCP is still the standard of reference •
for imaging the pancreatico-biliary system
there are specific advantages of MRCP over ERCP. •
MRCP (a) is noninvasive; (b) is cheaper; (c) uses
no radiation; (d) requires no anesthesia; (e) is less
operator dependent; (f) allows better
visualization of ducts proximal to an obstruction;
and (g) when combined with conventional T1and T2-weighted sequences, allows detection of
extraductal disease.
Disadvantages of MRCP
include (a) decreased spatial resolution, making •
MRCP less sensitive to abnormalities of the
peripheral intrahepatic ducts (eg, sclerosing
cholangitis) and pancreatic ductal side branches
(eg, chronic pancreatitis); and (b) imaging in the
physiologic, nondistended state, which decreases
the sensitivity to subtle ductal abnormalities.
Furthermore, the main criticism of MRCP is that
appropriate care is delayed in patients who need
therapeutic endoscopic or percutaneous
intervention of obstructing bile duct lesions.
Thus, it is argued that in patients
with high clinical suspicion for
bile duct obstruction, ERCP
should be the initial imaging
modality to provide timely
intervention (eg, dilatation, stent
placement, stone removal) if
necessary.
A small enhanced mass (arrow) in the pancreatic tail
is demonstrated at the arterial phase of -MRI
Abdominal MRI coronal view of
heterogeneous, well circumscribed
mass in the head of the pancreas