Gastro-Intestinal Tract

Pancreatitis

Mohamed Zaitoun

Assistant Lecturer-Diagnostic Radiology Department , Zagazig University Hospitals

EgyptFINR (Fellowship of Interventional

Neuroradiology)-Switzerlandzaitoun82@gmail.com

Knowing as much as possible about your enemy precedes successful battle

and learning about the disease process precedes successful management

Pancreatitis(I) Acute Pancreatitis(II) Chronic Pancreatitis

(I) Acute Pancreatitis :1-Etiology2-Clinical Picture3-Types4-Radiographic Features5-Complications6-Staging

1-Etiology :-Refers to acute inflammation of the pancreas and

is a potentially life threatening condition-The diagnosis of acute pancreatitis is made by

fulfilling two of the following three criteria :a) Acute onset of persistent, severe epigastric pain

(i.e. pain consistent with acute pancreatitis)b) Lipase/amylase elevation beyond three times

the upper limit of normal c) Characteristic imaging features on CECT, MRI

or US

-Causes :1-Alcohol abuse : most common cause of chronic

pancreatitis2-Gallstone passage/impaction: most common

cause of acute pancreatitis (up to 15% could develop pancreatitis)

3-Postoperative, post-ERCP, abdominal trauma4-Hyperlipidemia, hypercalcemia5-Drugs: azathioprine, thiazides, sulfonamides6-Inflammation: PUD7-Hyperparathyroidism8-Pregnancy

2-Clinical Picture :-Classical clinical features include :a) Acute onset of severe central epigastric

pain (over 30-60 min)b) Poorly localized tenderness and painc) Exacerbated by supine positioningd) Radiates through to the back in 50% of patientse) Elevation of amylase and lipase are 90-95%

specific for the diagnosis

3-Types :-There are two subtypes of acute pancreatitis : a) Interstitial Edematous Pancreatitis :-Vast majority (90-95%)-Most often referred to simply as "acute

pancreatitis" or "uncomplicated pancreatitis“b) Necrotizing Pancreatitis :-Necrosis develops within the pancreas and/or

peripancreatic tissue

Acute edematous pancreatitis, A,B: CT+C, venous phase, demonstrating diffuse pancreatic enlargement, densification of the peripancreatic fat planes (long arrows) and acute fluid collections in the left anterior pararenal space and in the left paracolic gutter (short arrows), without areas of parenchymal necrosis

Acute necrotizing pancreatitis, A,B: CT+C, venous phase, acute necrotizing pancreatitis in a 52-year-old male patient, diffuse hypoenhancement of the pancreatic neck, body and tail (arrows on A), compatible with presence of an extensive area of necrosis, with a small area of preserved parenchyma in the uncinate process (arrow on B), C,D : CT+C, venous phase, acute necrotizing pancreatitis in a 35-year- old woman, extensive areas of pancreatic parenchymal necrosis (long arrows) in association with areas of fat necrosis in the left anterior pararenal space and in the transverse mesocolon (short arrows).

IEP in a 25-year-old woman with alcohol abuse and epigastric pain for 72 hours, axial CT image shows the pancreas (arrowhead) to be slightly edematous and heterogeneously enhancing, APFCs (arrows) are seen surrounding the pancreas

Pancreatitis with pseudocyst in a 27-year-old woman, coronal CT reconstruction obtained 5 weeks after acute episode shows pseudocyst (arrows) with well-defined rim representing the capsule near the tail of the pancreas, gastric folds are slightly thickened (arrowheads)

Parenchymal necrosis in tail of the pancreas with ANCs in a 34-year-old man, axial CT image shows necrosis (arrowheads) in tail of the pancreas as lack of enhancement, multiple ANCs (arrows) are seen surrounding tail and body of the pancreas

WON of pancreatic body, tail, and portion of the head in a 45-year-old man with alcohol abuse and necrotizing pancreatitis, (a) Axial CT image obtained 6 weeks after acute onset shows some areas of lower attenuation (arrowheads) in a heterogeneous collection with a well-defined rim (arrows), representing WON with fat necrosis involving pancreas and peripancreatic tissues, (b) Axial CT image obtained several centimeters caudal to a shows WONs extending into right anterior pararenal and left anterior and posterior pararenal space (arrows)

4-Radiographic Features :a) US :-By US, an inflamed pancreas appears

hypoechoic relative to liver (reversal of normal pattern) because of edema

-US is mainly used for investigation of gallstones and/or to follow the size of pseudocysts

A stripe of fluid in front of pancreatic tissue marked by white arrows

(a) Transverse transabdominal US image through the upper abdomen shows a well-defined hypoechoic collection (arrows) with internal echogenic material (*) representing the nonliquefied components, (b) US image shows echogenic gallstones and sludge (arrows)

b) CT :-Focal or diffuse parenchymal enlargement-Changes in density because of edema-Indistinct pancreatic margins owing to

inflammation-Surrounding retroperitoneal fat stranding

Interstitial pancreatitis, the pancreas is swollen and there is peripancreatic inflammation, no fluid collections, no pancreatic necrosis

Interstitial pancreatits, CT+C shows satisfactory enhancement of pancreatic tissue, but there is some loss of marginal definition, in keeping with edema, and there is moderate swelling of Gerota's fascia (between arrowheads)

Coronal CT image of Interstitial edematous pancreatitis (IEP) in a 34-year-old man with acute onset of epigastric pain for 12 hours due to gallstones, pancreas (arrows) is heterogeneously enhanced, with indistinct margins due to inflammation of peripancreatic fat, some stranding and minimal fluid (arrowheads) are also present

Edema in the pancreas (arrows) and peripancreatic stranding and fluid (arrowheads)

CT+C shows diffusely enlarged pancreas with low density from edema, note the density of pancreas is less than liver and spleen with IV contrast, pancreas is wider than abdominal aortic diameter indicating that it has increased in size

Necrotizing pancreatitis, CT+C (a) show a normally enhancing pancreas on day 1, as the patient's condition worsened, a second CT was performed on day 3, (b) notice how the greater part of the pancreatic body and tail no longer enhances indicating necrotizing pancreatitis (arrows)

Necrotizing pancreatits, CT+C, arrow : no enhancement of pancreas with IV contrast, arrowheads : normal enhancement in the tail of Pancreas

5-Complications :a) Pancreatic Necrosis (Necrotizing Pancreatitis) b) Acute Peripancreatic Fluid Collection (APFC) c) Pseudocyst d) Pancreatic Abscess e) Infected Necrosis f) Hemorrhageg) Fistula formation with pancreatic ascites

a) Pancreatic Necrosis : (Necrotizing Pancreatitis)

-Necrosis of the pancreatic parenchyma with or without necrosis of the peripancreatic tissues

-Diffuse parenchymal (>30% of pancreatic area) or focal areas (>3 cm) of nonviable parenchyma, peripancreatic fat necrosis, and fluid accumulation (Acute necrotic collection “ANC” or walled-off necrosis “WON”)

-Imaging :*Lack of parenchymal enhancement*Often multifocal

Drawings illustrate pancreatic necrosis (a), peripancreatic necrosis (b), and combined pancreatic-peripancreatic necrosis (c)

Pancreatic necrosis in a 65-year-old man, (a) Axial CT+C obtained 2 days after the onset of acute abdominal pain shows peripancreatic fluid and stranding (arrows) and normal-appearing pancreatic parenchyma, (b) Axial CT+C obtained 5 days later owing to the patient’s worsening clinical condition reveals an ill-defined hypoattenuating region in the body of the pancreas (*), a finding that suggests pancreatic necrosis, peripancreatic fluid and stranding (arrows) are also seen

Peripancreatic necrosis in a 22-year-old man, (a) Axial CT+C shows stranding, increased attenuation, and a heterogeneous appearance of the peripancreatic fat around the body and tail of the pancreas (white arrows), a feeding tube is seen in the stomach (black arrow), (b) Axial CT+C acquired 20 days later reveals evolution of the heterogeneous peripancreatic collection into well-defined WON (Walled-off necrosis) (arrows)

Combined necrosis in a 46-year-old man, (a) Axial CT+C shows an ill-defined hypoattenuating region in the body and tail of the pancreas (*), along with ill-defined heterogeneous peripancreatic fluid, stranding, and increased fat attenuation (arrows), (b) Axial CT+C acquired 6 weeks later reveals evolution of the pancreatic and heterogeneous peripancreatic collection into well-defined WON (arrows), residual pancreatic parenchyma is seen in the tail (*)

b) Acute Peripancreatic Fluid Collection (APFC) : -Collections of enzyme-rich pancreatic fluid occur in

40% of patients-No fibrous capsule (in contradistinction to

pseudocysts)-Most common location is within and around the

periphery of the pancreas-Fluid collections are not limited to the anatomic

space in which they arise and may dissect into mediastinum, pararenal space, or organs (spleen, kidney, liver)

-Prognosis: 50% resolve spontaneously; the rest evolve into pseudocysts or are associated with other complications (infection, hemorrhage)

-Differentiation from pseudocyst difficult: test of time

Acute pancreatitis, the pancreas is enlarged (blue arrow) with indistinct and shaggy margins, there is peripancreatic fluid (red arrow) and extensive peripancreatic infiltration of the surrounding fat (black arrow)

c) Pseudocyst :-Encapsulated collection of pancreatic fluid, which

is typically round or oval-Surgical definition of pseudocyst requires

persistence at least 6 weeks from the onset of pancreatitis

-Occurs in 40% of patients with acute pancreatitis and in 30% of patients with chronic pancreatitis

-Bacteria may be present but are often of no clinical significance; if pus is present, the lesion is termed a pancreatic abscess

Chronic pancreatitis with an intrapancreatic pseudocyst in a 42-year-old man with a history of alcoholic pancreatitis, (a) CT+C shows a dilated pancreatic duct (arrows) with mild pancreatic atrophy, an appearance compatible with chronic pancreatitis, (b) CT scan shows a round mass with diffuse low attenuation in the pancreatic head (curved arrow), the mass represents a pseudocyst, note the dilated pancreatic duct (straight arrow), (c) CT+C shows pancreatic calcifications (arrow), a finding compatible with chronic pancreatitis

Chronic Pancreatitis With Pseudocyst And Calcifications

d) Pancreatic Abscess :-Intraabdominal fluid collection in or adjacent to the

pancreas that contains pus-Effectively treated by percutaneous drainage-Usually occurs >4 weeks after onset of acute

pancreatitis-Imaging :*Circumscribed fluid collection*Little or no necrotic tissues (thus distinguishing it

from infected necrosis)

(a) CT+C shows a heterogeneous hypoattenuating fluid collection with peripheral irregularity in the pancreatic body and tail (arrow), three weeks after conservative treatment, a spiking fever and marked leukocytosis developed, (b) CT scan obtained 3 weeks after conservative treatment shows an interval increase in the size of the fluid collection, which contains high-attenuation debris (arrow), the presence of infection was confirmed by means of percutaneous aspiration

e) Infected Necrosis :-Necrotic pancreatic (and/or peripancreatic)

tissue that can become infected-Differentiation from pancreatic abscess is

crucial for appropriate clinical treatment (see table)

-Imaging :*Difficult to distinguish from aseptic

liquefactive necrosis*Presence of gas is helpful

Large infected WON in a 57-year-old man with necrotizing pancreatitis, axial CT image obtained 5 weeks after acute onset shows pancreas replaced by low-attenuation collection with well-defined rim (arrows) and multiple pockets of gas (arrowheads)

Infected acute necrotizing pancreatitis in a 35-year-old man, CT+C, venous phase showing liquefied area in the pancreatic body, compatible with necrosis, with gas inside (arrows) without an outlined fluid gas level, but intermingled with the fluid, indicating the presence of thick fluid/pus content, in such a context, gas corresponds to the presence of infection

f) Hemorrhage :-Usually occurs as a late consequence of vascular injury,

commonly erosion into splenic or pancreaticoduodenal arteries

-May result from rupture of pseudoaneurysm-Imaging :*High-attenuation fluid in the retroperitoneum or

peripancreatic tissues

g) Fistula formation with pancreatic ascites :-Leakage of pancreatic secretions into peritoneal cavity

NECT shows acute Hemorrhagic Pancreatitis, enlarged tail of pancreas, white arrow : increased density in the enlarged tail of pancreas due to blood, fascial changes adjacent to tail of pancreas due to inflammation

6-Staging : CT Staging -Grade A : normal pancreatic appearance-Grade B : focal or diffuse enlargement of

pancreas-Grade C : pancreatic abnormalities and

peripancreatic inflammation-Grade D : 1 peripancreatic fluid collection-Grade E : >2 peripancreatic fluid collections

and/or gas in or adjacent to the pancreas

(II) Chronic Pancreatitis :1-Etiology2-Clinical Picture3-Radiographic Findings4-Groove Pancreatitis

1-Etiology :-The most common cause of chronic

pancreatitis in adults is excessive alcohol consumption in developed countries and malnutrition in developing countries

2-Clinical Picture :-Patients may present with exacerbations

(episodes of acute pancreatitis) manifesting as epigastric pain, which may recur over a number of years

3-Radiographic Findings :a) Plain Radiography :-Calcification

b) US :-The pancreas might appear atrophic, calcified or

fibrotic-Findings that may be present on ultrasound

include :*Hyperechogenicity (often diffuse) often indicates

fibrotic changes*Pseudocysts*Pseudoaneurysms*Presence of ascites

c) CT :CT features of chronic pancreatitis include : 1-Dilatation of the main pancreatic duct2-Pancreatic calcification3-Changes in pancreatic size (i.e. atrophy),

shape, and contour4-Pancreatic pseudocysts

Calcification in an atrophic pancreas

Duct dilatation

Pancreatic calcifications

4-Groove Pancreatitis :-Rare form of chronic pancreatitis that may mimic

pancreatic carcinoma-The term pancreaticoduodenal groove refers to

the potential space between the head of the pancreas, the duodenum, and the CBD

-Two forms of groove pancreatitis have been described :

a) Segmental Form :-Which involves the pancreatic head with

development of scar tissue within the grooveb) Pure Form :-Which affects the groove only, sparing the

pancreatic head

Groove pancreatitis with cystic dystrophy of the duodenal wall, drawing illustrates the disease process in groove pancreatitis, inflammation is predominantly centered in the pancreaticoduodenal groove, with multiple cystic lesions within the medial wall of the duodenum (D)

-At CT, the classic finding is soft tissue within the pancreaticoduodenal groove; this tissue may demonstrate delayed enhancement, small cystic lesions may be seen along the medial wall of the duodenum

Groove pancreatitis with cystic dystrophy of the duodenal wall, (a) Transverse US image through the pancreas (P) demonstrates a sheetlike hypoechoic area in the pancreaticoduodenal groove with areas of cystic change (arrowhead), (b, c) Venous phase CT scans show a hypoattenuating area in the pancreaticoduodenal groove (arrow in b) with inflammatory stranding within the surrounding fat and in the right anterior pararenalparaduodenal space (arrows in c). P = pancreas