pancreatic diseases. acute pancreatitis acute pancreatitis (ap) is an acute inflammatory condition...

Pancreatic DiseasesPancreatic 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 interstitialinterstitial pancreatitis pancreatitis, based on its

radiographic appearance.

• Severe AP implies the presence of organ failure, local

complications, or pancreatic necrosis.


Causes of Acute Pancreatitis (% of Cases)1.1. Gallstones: 45% Gallstones: 45% 2.2. Alcohol: 35%Alcohol: 35% 3. Other 10%

Medications Hypercalcemia Hypertriglyceridemia Obstructive Post-ERCP Hereditary Trauma Viral Vascular/ischemic Postcardiac bypass

4. Idiopathic: 10%

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.


Diagnosis• According to the ACG guidelines, the diagnosis of AP is supported by an

elevation of the serum amylase and lipaseelevation 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 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 diagnosticnot diagnostic and frequently normal or may demonstrate:1. sentinel loop 2. colon cut off 3. diffuse ileus 4. pleural effusion


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

Plain films

Sentinel loop -

a focal dilated proximal jejunal loop in the left upper quadrant


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

Plain films

distention of the colon to the transverse colon with a paucity of gas distal to the splenic flexure

Acute Pancreatitis Acute Pancreatitis US Findings

Although transabdominal ultrasound is poorly reliable for imaging

the pancreas itself, it is the best initial radiographic testthe best initial radiographic test for the

evaluation of mild AP because:

1. it detects gallstones as a potential cause,

2. it rules out acute cholecystitis as a differential cause of pain and

hyperamylasemia, and

3. it detects biliary dilatation suggestive of the need for early

endoscopic retrograde cholangiopancreatography (ERCP).

The pancreas may appear completely normal The pancreas may appear completely normal in mild cases of acute pancreatitis. in mild cases of acute pancreatitis.

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.

3. The pancreatic duct may be enlarged secondary to inflammation, spasm, edema, swelling of the papilla, or pseudocyst formation.

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.

Acute Pancreatitis Acute Pancreatitis CT Findings

Contrast-enhanced computed tomography (CT) of the abdomen is the is the preferred testpreferred 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 "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 the first 3 days in severe acute pancreatitis (on the basis of a high

APACHE score or organ failure) to distinguish interstitial from APACHE score or organ failure) to distinguish interstitial from necrotizing pancreatitis.„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 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

Normal pancreas

CT scan obtained with intravenous and oral contrast material shows an enlarged and homogeneously

enhancing pancreatic gland.


Complications of acute pancreatitis may lead to:

• necrosis,

• hemorrhagic pancreatitis,

• phylegmon formation,

• abscess,

• venous thrombosis

• pseudocyst formation

• pancreatic pseudoaneurysm

NORMAL


BALTHAZAR Grading System for Severityof Acute Pancreatitis According to CT Criteria

GradeCT Findings

(Contrast or Noncontrast)

A Normal pancreas

BFocal 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.

The severity of pancreatitis detected on CT may be staged based on the Balthazar system

Acute Pancreatitis 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%

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


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.



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



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



Complications

Contrast-enhanced CT scan reveals development of large pseudocysts in the neck and tail of the pancreas.

A pseudocystpseudocyst appears as an oval or round water density collection with a thin or thick wall, which may enhance


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.

Complications

From: Cystic Lesions of the Pancreas Terrence C. Demos et al. AJR 2002; 179:1375-1388

A pancreatic abscesspancreatic abscess can manifest as a thick-walled low-attenuation fluid collection with gas bubbles or a poorly defined fluid collection with mixed densities/attenuation.

Acute Pancreatitis Acute Pancreatitis Complications

A pancreatic phlegmonpancreatic 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.

Venous thrombosisVenous 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 Acute Pancreatitis Complications


A ppancreatic pseudoaneurysmancreatic pseudoaneurysm is a malformation in the vessels of the pancreas and/or peripancreatic bed.

Complications

Mesenteric artery angiogram demonstrating contrast extravasating

into a pseudoaneurysm

A CT scan with intravenous contrast enhancement within a pancreatic

pseudocyst indicating the presence of a pseudoaneurysm.


Pancreatic or peripancreatic bleedingPancreatic 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.

Complications

Preembolization angiogram depicting a splenic artery pseudoaneurysm.

Postembolization angiogram depicting successful coil embolization of the

pseudoaneurysm.


Diagnosis• According to the ACG guidelines, the diagnosis of AP is supported by an

elevation of the serum amylase and lipaseelevation 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)


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.

MRI Findings

From: MR Imaging of the Pancreas: A Pictorial Tour C. Matos et al. Radiographics. 2002;22:e2.

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.

Acute Pancreatitis Acute Pancreatitis MRI Findings

From: MR Imaging of the Pancreas: A Pictorial Tour C. Matos et al. Radiographics. 2002;22:e2.

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.


ERCP allows identification and removal of common-bile-duct stones in suspected gallstone suspected gallstone

pancreatitispancreatitis.

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.

Endoscopic retrograde cholangiopancreatography (ERCP)

Slightly dilated common bile duct with calculus and normal pancreatic

duct are shown

ChronicChronic Pancreatitis Pancreatitis

ChronicChronic Pancreatitis 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 processesdifferent disease processes, and most cases of acute

pancreatitis do not result in chronic disease.


The main causes of chronic pancreatitis include the following: • Alcoholism:Alcoholism: Alcoholism is associated with chronic pancreatitis

in 60-90% of patients. • Cholelithiasis:Cholelithiasis: Cholelithiasis is a common cause of acute

pancreatitis, but it probably is associated with chronic pancreatitis in 20-25% of patients.

• Idiopathic: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 can be classified into 3 categories:

1.1. Chronic calcifying pancreatitisChronic calcifying pancreatitis is invariably related to alcoholism.

2. In c chronic obstructive pancreatitishronic 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.

3.3. Chronic inflammatory pancreatitisChronic inflammatory pancreatitis is rare and can affect elderly persons without a previous history of alcohol excess.

The main duct of the pancreas is dilated and contains calcified secretions


Preferred Examination

• Plain film of the abdomen

• CT

• Ultrasonography

• MRI, particularly MRCP

• ERCP

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.

ChronicChronic Pancreatitis Pancreatitis Plain films• Pancreatic calcificationPancreatic calcificationss 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.

ChronicChronic Pancreatitis 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 signpad sign.

Upper gastrointestinal tract barium study shows a reverse 3 in the duodenum due to chronic pancreatitis.

Pancreatic carcinoma can have a similar appearance

ChronicChronic Pancreatitis Pancreatitis CT Findings

Currently, CT is regarded as the imaging modality of choiceimaging 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.


The sensitivity of plain film for detection of pancreatic calcificationspancreatic calcifications is about 80 %, which is higher than that of sonography but lower than that of CT.

CT Findings

ChronicChronic Pancreatitis Pancreatitis Ultrasound

• Ultrasonography is the first the first modality to be used in patients modality to be used in patients presenting with upper abdominal presenting with upper abdominal painpain, 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 structureof pancreatic tissue.

ChronicChronic Pancreatitis 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


ERCP is the most sensitive and specific technique in the investigation of chronic pancreatitis, although it is invasive and may cause an acute episode it is invasive and may cause an acute episode of pancreatitis and ascending cholangitis. of pancreatitis and ascending cholangitis.

Endoscopic retrograde cholangiopancreatography (ERCP)

ERCP of normal pancreatic and biliary ducts.

ChronicChronic Pancreatitis Pancreatitis Endoscopic retrograde cholangiopancreatography (ERCP)

Mild pancreatitisMild pancreatitis may present with minimal dilation of the main pancreatic duct and some clubbing of the side branches of the duct


The patient with moderately-moderately-staged chronic staged chronic pancreatitispancreatitis 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


A characteristic "chain of "chain of lakes"lakes" appearance of the main pancreatic duct can be noted on ERCP in patients with severe severe chronic pancreatitischronic 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

ChronicChronic Pancreatitis Pancreatitis MRI Findings

MRI, particularly MRCP, MRI, particularly MRCP, is a noninvasive is a noninvasive technique. 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 gadolinium-enhanced (D) T1-weighted images, demonstrate diffuse enhancement of the sheetlike mass, which corresponded to fibrotic tissue.

Groove pancreatitis

• Involvement of the common bile duct may be visualized as a gradually gradually tapering of the lumentapering of the lumen of the obstructed common bile duct.

ChronicChronic Pancreatitis Pancreatitis MRCP and ERCP

MRCP image in patient with chronic pancreatitis shows reduced

duodenal filling.

ChronicChronic Pancreatitis Pancreatitis MRCP and ERCP

• By contrast, a pancreatic carcinomapancreatic carcinoma usually results in an abrupt transitionan 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.


Complications of chronic pancreatitis include: • pseudocyst formationpseudocyst 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 PancreasCystic 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


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

PseudocystPseudocyst

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 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.


PseudocystPseudocystWhen cysts are chronic, the

cyst wall can calcify

CT scan shows pseudocyst with calcified wall in head of

pancreas.



Upper GI tract barium study shows displacement and stretching of duodeno-jejunal junction.

A catheter in a dilated common bile duct.

Symptoms related to complications of pseudocyst include jaundice due to extrahepatic bile duct obstruction and signs of duodenal obstruction.

Mucinous adenocarcinomaMucinous adenocarcinomaAdenocarcinoma is the most common pancreatic neoplasm.

Mucinous adenocarcinoma 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).


pancreatic diseases. acute pancreatitis acute pancreatitis (ap) is an acute inflammatory condition...

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