Transcript PZ - Pancreatic Diseases

Pancreatic Diseases
Acute Pancreatitis
Acute Pancreatitis
Acute pancreatitis (AP) is an acute inflammatory condition of
the pancreas that may extend to local and distant
extrapancreatic tissues.
The American College of Gastroenterology (ACG) practice
guidelines provide acceptable terminology for the
classification of AP and its complications.
AP is broadly classified as mild or severe:
• Mild AP is often referred to as interstitial pancreatitis, based on its
radiographic appearance.
• Severe AP implies the presence of organ failure, local complications,
or pancreatic necrosis.
Acute Pancreatitis
The yearly incidence of AP in the United States is approximately 17 new
cases per 100,000 population. Acute pancreatitis results in 100,000
hospitalizations per year.
80% of cases of AP are interstitial and mild; the remaining 20% are
necrotizing and severe. Approximately 2,000 patients per year die from
complications related to AP.
Causes of Acute Pancreatitis (% of Cases)
1. Gallstones: 45%
2. Alcohol: 35%
3. Other 10%
Medications
Hypercalcemia
Hypertriglyceridemia
Obstructive
Post-ERCP
Hereditary
Trauma
Viral Vascular/ischemic
Postcardiac bypass
4. Idiopathic: 10%
Acute Pancreatitis
Diagnosis
• According to the ACG guidelines, the diagnosis of AP is supported by an
elevation of the serum amylase and lipase in excess of three times the upper
limit of normal.
Radiologic Studies:
1. Plain films of the chest and abdomen
2. Transabdominal ultrasound
3. Contrast-enhanced computed tomography
4. Endoscopic ultrasound
5. MRI and magnetic resonance cholangiopancreatography (MRCP)
6. Endoscopic retrograde cholangiopancreatography (ERCP)
Acute Pancreatitis
Plain films
An abdominal radiograph is helpful for excluding other causes of acute
abdominal pain, such as obstruction and perforation.
The abdominal (or chest radiograph) is not diagnostic and frequently
normal or may demonstrate:
1. sentinel loop
2. colon cut off
3. diffuse ileus
4. pleural effusion
Acute Pancreatitis
Plain films
The abdominal radiograph is not diagnostic and frequently normal or may
demonstrate:
1. sentinel loop
2. colon cut off
Sentinel loop 3. diffuse ileus
4. pleural effusion
a focal dilated
proximal jejunal
loop in the left
upper quadrant
Acute Pancreatitis
Plain films
The abdominal radiograph is not diagnostic and frequently normal or may
demonstrate:
1. sentinel loop
2. colon cut off
3. diffuse ileus
4. pleural effusion
distention of the colon
to the transverse
colon with a paucity of
gas distal to the
splenic flexure
Acute Pancreatitis
US Findings
Although transabdominal ultrasound is poorly reliable for imaging
the pancreas itself, it is the best initial radiographic test for the
evaluation of mild AP because:
1.
2.
3.
it detects gallstones as a potential cause,
it rules out acute cholecystitis as a differential cause of pain and
hyperamylasemia, and
it detects biliary dilatation suggestive of the need for early
endoscopic retrograde cholangiopancreatography (ERCP).
The pancreas may appear completely normal
in mild cases of acute pancreatitis.
Acute Pancreatitis
US Findings
1. In the early stages of
acute pancreatitis, the
gland may not show
swelling. When swelling
does occur, the gland is
hypoechoic to anechoic
because of the increased
edema.
2. On the longitudinal scan,
the swollen head of the
pancreas may
compress the inferior
vena cava.
Image shows that pancreatic echogenicity is within normal limits, but the
gland is mildly enlarged. In addition, a complex fluid collection lies anterior
to the pancreas, and abnormal sonolucency surrounds the splenic vein.
3. The pancreatic duct
may be enlarged
secondary to
inflammation, spasm,
edema, swelling of the
papilla, or pseudocyst
formation.
Acute Pancreatitis
CT Findings
Contrast-enhanced computed tomography (CT) of the abdomen is the
preferred test for evaluating severe pancreatitis and detecting complications.
A CT should not be routinely ordered for all patients with AP; however,
The American College of Gastroenterology (ACG) practice guidelines
state that:
"a dynamic contrast-enhanced CT is recommended at some point beyond
the first 3 days in severe acute pancreatitis (on the basis of a high
APACHE score or organ failure) to distinguish interstitial from necrotizing
pancreatitis.„
• A CT should also be considered for those in whom a localized pancreatic
complication is suspected (eg, pseudocyst, splenic vein thrombosis,
splenic artery aneurysm).
• CT is also appropriate after resolution of AP to exclude a tumor if the
cause of the attack is unclear.
Acute Pancreatitis
CT features in interstitial
pancreatitis include:
1. homogenous contrast
enhancement;
2. diffuse or segmental
pancreatic enlargement;
3. irregularity, heterogeneity,
and lobularity of the
pancreas;
4. obliteration of the
peripancreatic fat planes
CT scan obtained with intravenous and oral contrast
material shows an enlarged and homogeneously
enhancing pancreatic gland.
Normal pancreas
Acute Pancreatitis
CT Findings
Complications of acute pancreatitis may lead to:
• necrosis,
• hemorrhagic pancreatitis,
• phylegmon formation,
• abscess,
• venous thrombosis
• pseudocyst formation
• pancreatic pseudoaneurysm
NORMAL
Acute Pancreatitis
The severity of pancreatitis detected on CT may be staged based on the
Balthazar system
BALTHAZAR Grading System for Severity
of Acute Pancreatitis According to CT Criteria
CT Findings
(Contrast or Noncontrast)
Grade
A
Normal pancreas
B
Focal or diffuse glandular enlargement, irregular contour of the gland,
heterogeneous attenuation, no peripancreatic inflammation
C
Same findings as Grade B, with peripancreatic inflammation
D
Same findings as Grade C, with a single fluid collection
E
Same findings as Grade C, with multiple fluid collections or abscess formation
Adapted from Balthazar EJ, et al. Radiology. 1990:174:331.
Acute Pancreatitis
CT Severity Index
The CT severity index is an attempt to improve the early prognostic value
of CT in cases of acute pancreatitis. Patients with grade A–E pancreatitis
are assigned zero to four points plus two points for necrosis of up to 30%,
four points for necrosis of 30%–50%, and six points for necrosis of more
than 50%
Acute Pancreatitis
CT Severity Index
Mortality of Acute Pancreatitis
Type
Mortality Rate
Interstitial AP
<1%
Necrotizing AP
Sterile
10%
Infected
30%
There was a statistically significant
correlation, with a continuous increasing
incidence of morbidity and mortality in
patients stratified according to CT
severity index groups.
Patients who had a severity index of 0 or 1
exhibited a 0% mortality rate and no
morbidity, while patients with severity
index of 2 had no mortality and a 4%
morbidity rate.
In contrast, a severity index of 7–10
yielded a 17% mortality rate and a 92%
complication rate
Acute Pancreatitis
CT Findings
Transverse
nonenhanced CT scan
shows a homogeneously
enlarged pancreas.
There are large
heterogeneous
peripancreatic fluid
collections.
peripancreatic fluid
collections.
Gland necrosis cannot
be ruled out.
Grade C
Severity Index 2
From: Acute Pancreatitis: Assessment of Severity with Clinical and CT Evaluation
Emil J. Balthazar, MD Radiology 2002;223:603-613.
Acute Pancreatitis
CT Findings
Contrast-enhanced CT
scan reveals two zones
of liquefied pancreatic
necrosis in the neck
and tail of the gland.
There are residual
nodular areas adjacent
to the tail of the
pancreas, consistent
with fat necrosis
(curved arrow).
Grade D
Severity Index 7
From: Acute Pancreatitis: Assessment of Severity with Clinical and CT Evaluation
Emil J. Balthazar, MD Radiology 2002;223:603-613.
Acute Pancreatitis
CT Findings
CT scans reveal an encapsulated fluid collection associated with liquefied necrosis in the body
of the pancreas. The head, part of the body, and the tail of the pancreas are still enhancing.
Residual fluid collections and areas of soft-tissue attenuation (curved arrow) consistent with fat
necrosis are seen adjacent to the pancreas. f = fluid, N = liquefied gland necrosis, S = stomach.
Grade E, Severity Index 10
From: Acute Pancreatitis: Assessment of Severity with Clinical and CT Evaluation
Emil J. Balthazar, MD Radiology 2002;223:603-613.
Acute Pancreatitis
Complications
A pseudocyst appears as an oval or round water density collection with a
thin or thick wall, which may enhance
Contrast-enhanced CT scan reveals
development of large pseudocysts in the
neck and tail of the pancreas.
From: Acute Pancreatitis: Assessment of Severity with Clinical and CT Evaluation
Emil J. Balthazar, MD Radiology 2002;223:603-613.
Acute Pancreatitis
Complications
A pancreatic abscess can manifest as a thick-walled low-attenuation fluid
collection with gas bubbles or a poorly defined fluid collection with mixed
densities/attenuation.
CT scan shows large fluid
collection containing gas
bubbles in pancreatic bed
due to abscess
complicating acute
pancreatitis. Note
infiltration of
peripancreatic fat and
calcified gallstones.
From: Cystic Lesions of the Pancreas Terrence C. Demos et al. AJR 2002; 179:1375-1388
Acute Pancreatitis
Complications
A pancreatic phlegmon is an inflammatory mass in and around the pancreas
formed by oedema and continued leakage of activated pancreatic enzymes. It
may resolve spontaneously, or progress to pseudocyst, necrosis or abscess.
Acute Pancreatitis
Complications
Venous thrombosis can be identified as a failure of the peripancreatic vein
(eg, splenic vein, portal vein) to enhance or as an intraluminal filling defect.
Acute Pancreatitis
Complications
A pancreatic pseudoaneurysm is a malformation in the vessels of the pancreas
and/or peripancreatic bed.
A CT scan with intravenous contrast
enhancement within a pancreatic
pseudocyst indicating the presence of a
pseudoaneurysm.
Mesenteric artery angiogram
demonstrating contrast extravasating
into a pseudoaneurysm
Acute Pancreatitis
Complications
Pancreatic or peripancreatic bleeding is one of the most life-threatening
complications of pancreatitis.
The standard of care in dealing with pseudoaneurysms has been surgical
intervention; recently, many interventional radiologists have reported excellent
outcome after angioembolization.
Preembolization angiogram depicting
a splenic artery pseudoaneurysm.
Postembolization angiogram depicting
successful coil embolization of the
pseudoaneurysm.
Acute Pancreatitis
Diagnosis
• According to the ACG guidelines, the diagnosis of AP is supported by an
elevation of the serum amylase and lipase in excess of three times the upper
limit of normal.
Radiologic Studies:
1. Plain films of the chest and abdomen
2. Transabdominal ultrasound
3. Contrast-enhanced computed tomography
4. Endoscopic ultrasound
5. MRI and magnetic resonance cholangiopancreatography (MRCP)
6. Endoscopic retrograde cholangiopancreatography (ERCP)
Acute Pancreatitis
MRI Findings
MRI is an alternative in situations in which
CECT is contraindicated, such as in
patients with contrast allergy or renal
insufficiency.
Acute necrotizing pancreatitis.
In A, a distal common bile duct stricture (arrow),
abnormal pancreatic duct side branches (solid
arrowheads) and indirect signs of duodenal wall
thickening (open arrowheads) are visualized.
The peripancreatic fluid collections detected in B
(arrows) are not detected in A, because of the
shorter T2 relaxation time of the fluid in the
peripancreatic collections.
From: MR Imaging of the Pancreas: A Pictorial Tour C. Matos et al.
Radiographics. 2002;22:e2.
Acute Pancreatitis
MRI Findings
MRI was found to be equivalent to CECT in helping assess the location and
extent of peripancreatic inflammatory changes and fluid collections.
In addition, MRI was found to be equivalent in helping assess the degree of
pancreatic necrosis.
Patient with acute
pancreatitis and
peripancreatic exudate.
Non-fat-suppressed (A, C)
and fat-suppressed (B, D)
T2-weighted images.
Increased signal intensity
of peripancreatic fat
tissues (arrows) is better
demonstrated in B and D.
From: MR Imaging of the Pancreas: A Pictorial
Tour C. Matos et al. Radiographics. 2002;22:e2.
Acute Pancreatitis
Endoscopic retrograde cholangiopancreatography (ERCP)
ERCP allows identification and
removal of common-bile-duct
stones in suspected gallstone
pancreatitis.
Because of its invasive nature
and the inherent risk of
worsening pancreatitis, it should
be performed only in the setting
of ongoing biliary obstruction
and cholangitis.
Slightly dilated common bile duct
with calculus and normal pancreatic
duct are shown
Chronic Pancreatitis
Chronic Pancreatitis
Chronic pancreatitis represents a continuous, prolonged,
inflammatory and fibrosing process of the pancreas with
irreversible morphologic changes resulting in permanent
endocrine and exocrine pancreatic dysfunction.
Acute pancreatitis and chronic pancreatitis are assumed to be
different disease processes, and most cases of acute
pancreatitis do not result in chronic disease.
Chronic Pancreatitis
The main causes of chronic pancreatitis include the following:
• Alcoholism: Alcoholism is associated with chronic pancreatitis
in 60-90% of patients.
• Cholelithiasis: Cholelithiasis is a common cause of acute
pancreatitis, but it probably is associated with chronic
pancreatitis in 20-25% of patients.
• Idiopathic: Etiology is idiopathic in 10-40% of patients.
• Cystic fibrosis: This disease is associated with pancreatic
atrophy and chronic pancreatitis
• Other conditions: hyperlipidemia, hyperparathyroidism,
uremia, drug use, hereditary causes, autoimmune conditions,
congenital causes (a congenital abnormality of fusion,
pancreas divisum)
Chronic Pancreatitis
Chronic pancreatitis can be classified into 3 categories:
1. Chronic calcifying pancreatitis is invariably related to alcoholism.
The main duct of the pancreas is
dilated and contains calcified
secretions
2. In chronic obstructive pancreatitis, the prominent histologic changes
are periductal fibrosis and subsequent ductal dilatation. These
changes are much more focal than those in the other forms, and in
most patients, the changes involve only the portion of the pancreas in
which ductal drainage is impaired. Diffuse changes may occur, in
which the main pancreatic duct or ampulla is obstructed.
3. Chronic inflammatory pancreatitis is rare and can affect elderly
persons without a previous history of alcohol excess.
Chronic Pancreatitis
Signs and symptoms
• Chronic pancreatitis is a relapsing condition that presents with
abdominal pain, occurring in 95% of cases.
• Pain can be episodic, lasting hours to days, or it can persist for
months or even years. The pain is characteristically steady in the
epigastrium, and it frequently radiates to the back.
• Weight loss and signs of exocrine and endocrine dysfunction are
also common symptoms.
Preferred Examination
• Plain film of the abdomen
• CT
• Ultrasonography
• MRI, particularly MRCP
• ERCP
Chronic Pancreatitis
Plain films
• Pancreatic calcifications are shown in 25-59% of patients.
• This feature is pathognomonic for chronic pancreatitis.
• Calcification is punctate or coarse, and it may have a focal, segmental, or
diffuse distribution.
chronic pancreatitis with
marked calcification of the
pancreatic parenchyma.
Chronic Pancreatitis
Upper GI tract barium series
The anatomic proximity of the pancreatic head and stomach antrum is
constant, and enlargement of the pancreatic head usually causes
effacement of the antrum. This finding has been termed the pad sign.
Upper gastrointestinal tract barium
study shows a reverse 3 in the
duodenum due to chronic pancreatitis.
Pancreatic carcinoma can have a
similar appearance
Chronic Pancreatitis
CT Findings
Currently, CT is regarded as the
imaging modality of choice for the
initial evaluation of suggested
chronic pancreatitis.
The diagnostic features of:
• pancreatic enlargement,
• pancreatic calcifications,
• pancreatic ductal dilatation,
• thickening of the peripancreatic
fascia, and
• bile duct involvement
are depicted well on CT scans.
Chronic Pancreatitis
CT Findings
The sensitivity of plain film for detection of pancreatic calcifications is about
80 %, which is higher than that of sonography but lower than that of CT.
Chronic Pancreatitis
Ultrasound
• Ultrasonography is the first
modality to be used in patients
presenting with upper abdominal
pain, although the direct
diagnosis of chronic pancreatitis
is not always possible.
• In early disease, the pancreas
may be enlarged and
hypoechoic, with ductal
dilatation. Later, the pancreas
becomes heterogeneous, with
areas of increased echogenicity
and focal or diffuse enlargement.
Chronic pancreatitis in phase of
exacerbation - an uneven outline of the
gland and heterogeneous structure
of pancreatic tissue.
Chronic Pancreatitis
Ultrasound
• In late stages of the disease, the pancreas becomes atrophic and fibrotic,
and it shrinks. These changes result in a small, echogenic pancreas with
a heterogeneous echotexture.
• Pseudocysts may occur, and focal hypoechoic inflammatory masses may
mimic pancreatic neoplasia.
• Calculi and calcification in the gland result in densely echogenic foci,
which may show shadow
Chronic Pancreatitis
Endoscopic retrograde cholangiopancreatography (ERCP)
ERCP is the most sensitive and specific technique in the investigation of
chronic pancreatitis, although it is invasive and may cause an acute episode
of pancreatitis and ascending cholangitis.
ERCP of normal
pancreatic and
biliary ducts.
Chronic Pancreatitis
Endoscopic retrograde cholangiopancreatography (ERCP)
Mild pancreatitis
may present with
minimal dilation of
the main
pancreatic duct
and some clubbing
of the side
branches of the
duct
Chronic Pancreatitis
Endoscopic retrograde cholangiopancreatography (ERCP)
The patient with
moderatelystaged chronic
pancreatitis
shows moderate
dilation of the
main pancreatic
duct (1.5 times
the normal size)
This is
accompanied by
moderate
clubbing of the
side branches of
the main
pancreatic duct
Chronic Pancreatitis
Endoscopic retrograde cholangiopancreatography (ERCP)
A characteristic "chain of
lakes" appearance of the
main pancreatic duct can
be noted on ERCP in
patients with severe
chronic pancreatitis.
The main pancreatic duct
is enlarged (greater than
1.5 times) with increased
tortuosity.
There is severe clubbing
and dilation of the side
branches.
Stone formation and
occlusion of the
pancreatic duct may
occur in this stage of the
disease
Chronic Pancreatitis
MRI Findings
Groove pancreatitis
MRI, particularly MRCP,
is a noninvasive
technique.
The combination of
pancreatic parenchyma
imaging sequences
with MR angiography
and secretin-enhanced
MRCP offers the
possibility of a
comprehensive
examination within a
single diagnostic
modality for evaluation
of the full range of
pancreatic diseases.
(A) MRCP demonstrates a "double duct" stricture with proximal dilatation
of the common bile duct and pancreatic duct (arrow). A cystic lesion is seen
between the common bile duct and the duodenal wall. (B) Fat-suppressed
TSE T1-weighted image. Unenhanced (C) and delayed gadoliniumenhanced (D) T1-weighted images, demonstrate diffuse enhancement of the
sheetlike mass, which corresponded to fibrotic tissue.
Chronic Pancreatitis
MRCP and ERCP
• Involvement of the
common bile duct may be
visualized as a gradually
tapering of the lumen of
the obstructed common
bile duct.
MRCP image in patient with chronic
pancreatitis shows reduced
duodenal filling.
Chronic Pancreatitis
MRCP and ERCP
• By contrast, a
pancreatic carcinoma
usually results in
an abrupt transition
of the common bile duct.
Dynamic MRCP images in a
patient with an ampullary tumor
shows an increase in the caliber
of the pancreatic duct.
Associated biliary tract dilatation
is seen - double-duct sign.
Chronic Pancreatitis
Complications of chronic pancreatitis include:
• pseudocyst formation
• fistula formation
• pseudoaneurysms of large arteries close to the pancreas
• stenosis of the common bile duct
• splenic and/or portal venous obstruction
• Diabetes can develop in 70-90% of patients with chronic
calcific pancreatitis
Cystic Lesions of the Pancreas
Cystic pancreatic lesions are regularly encountered on imaging
studies of patients who are symptomatic or as unexpected
abnormalities in patients who are being examined for other
reasons.
A wide variety of cystic lesions of the pancreas are seen, but
pseudocysts are by far most common.
Cystic neoplasms are often misdiagnosed as pseudocysts.
This indicates the difficulty in diagnosis and at the same time
emphasizes the need to obtain clinical information to provide
the most accurate diagnosis
From: Cystic Lesions of the Pancreas Terrence C. Demos et al. AJR 2002; 179:1375-1388
Pseudocyst
Panceatic and parapancreatic fluid collections are most often
complications of pancreatitis.
These fluid collections can resolve spontaneously, but those that do not are
recognized as pseudocysts on imaging studies when a well-defined wall
becomes visible. This wall consists of fibrous tissue, but unlike true cysts,
lymphoepithelial cysts, and most cystic neoplasms, a pseudocyst has no
epithelial lining
A typical pseudocyst, however, is a uniform, low-attenuation
fluid collection with a thin uniform wall that enhances after the
administration of IV contrast material
From: Cystic Lesions of the Pancreas Terrence C. Demos et al. AJR 2002; 179:1375-1388
Pseudocyst
On CT, a typical pseudocyst,
however, is a uniform, low-attenuation
fluid collection with a thin uniform wall
that enhances after the administration
of IV contrast material.
On sonography, uncomplicated
pseudocysts are generally hypoechoic
with variable through-transmission, but
hemorrhage or necrotic debris will
produce internal echogenicity.
From: Cystic Lesions of the Pancreas Terrence C. Demos et al. AJR 2002; 179:1375-1388
Pseudocyst
When cysts are chronic, the
cyst wall can calcify
CT scan shows pseudocyst
with calcified wall in head of
pancreas.
From: Cystic Lesions of the Pancreas Terrence C. Demos et al. AJR 2002; 179:1375-1388
Pseudocyst
Symptoms related to
complications of pseudocyst
include jaundice due to
extrahepatic bile duct obstruction
and signs of duodenal obstruction.
Upper GI tract barium study
shows displacement and
stretching of duodeno-jejunal
junction.
A catheter in a dilated common
bile duct.
Mucinous adenocarcinoma
Adenocarcinoma is the most common pancreatic neoplasm.
Mucinous adenocarcinoma is an uncommon variant of adenocarcinoma.
This neoplasm produces a large volume of mucin that results in a cystic
appearance on imaging studies
CT scan shows well-defined
cystic component of mass in
tail of pancreas. Note liver
metastasis (arrow).
From: Cystic Lesions of the Pancreas Terrence C. Demos et al. AJR 2002; 179:1375-1388