ct imaging of acute pancreatitis

7/29/2019 CT Imaging of Acute Pancreatitis

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CT Imaging of Acute

Pancreatitis

Erin Rikard

RadiologyDecember 2007


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Outline

Definition

Epidemiology

Causal Factors

Pathophysiology CT Evaluation and Findings Normal and

abnormal

Complications

Management

Prognosis


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Definition


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Definition

AcutePancreatitis-

Inflammationof

pancreaswith

potentialfor

completehealing


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Epidemiology


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Epidemiology

79.8/100,000 per year 185,000 new

cases annually in U.S.

Peak incidence in 6th decade


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Causal Factors


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Causal Factors

Etiology Incidence

Cholelithiasis 30-60%

Alcohol 15-30%

Iatrogenic 2-5%

Trauma/Surgery --

Metabolic Disorders --

Viral Infection --


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Pathophysiology


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Pathophysiology

Pancreatic autodigestion, with activated

pancreatic enzymes escaping the ductal

system and lysing tissue of pancreas and

adjacent structures

Lack of capsule facilitates spread


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Normal CT

Findings


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Normal Anatomy by CT

Pancreas arcing

anteriorly over spine

Head adjacent to

duodenum

Tail extending toward

spleen

Splenic vein posterior to

body and tail

Portal vein confluence

immediately posterior &

left of pancreatic neck


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Normal Morphology by CT

Pancreatic acini lobulated contour

No capsule

AP dimensions

Head 2-2.5 cm

Body and tail 1-2 cm

Pancreatic duct

Maximal diameter 3 mm in adults (5 mm in elderly) Empties into ampulla of Vater, along medial aspect

of 2nd portion of duodenum


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50 year-old woman

CT scans of normal kidneys and pancreas

Spleen

L

KidneyR

Kidney

A

Stomach

Liver

V

Pancreas


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Evaluation by CT


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Evaluation of Acute Pancreatitis

Contrast-enhanced CT is imaging modality

of choice

Oral and IV contrast differentiate

pancreatic tissue from adjacent blood

vessels and duodenum


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Recommendations for Contrast-

Enhanced CT

Clinical diagnosis in doubt

Severe clinical pancreatitis

Ranson score > 3 APACHE score > 8

Failure to rapidly improve within 72 hours

of beginning conservative medical therapy Initial improvement with later deterioration


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Ranson Criteria

At admission

Age > 55

WBC > 16,000

Blood glucose > 200

Serum AST > 250

Serum LDH > 350

After 48 hours

Hematocrit > 10% BUN 1.8 after

rehydration

Serum calcium < 8.0

PO2 < 60 Base deficit > 4

Estimated fluid

sequestration > 6L


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Abnormal CT

Findings


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Peripancreatic inflammation

Diffuse or focal pancreatic edema

Poor definition and heterogeneity of

gland

Fluid collections

Necrosis

Thickening of pararenal fascia

Abnormal CT Findings


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Spectrum of Disease

Mild Cases

May be normal or

show only mild gland

enlargement

Severe Cases

May reveal

peripancreatic fluid

&/or pancreaticnecrosis and

phlegmon


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Peripancreatic Inflammation/

Pancreatic Edema/Fluid Collections

Gallstone induced pancreatitis in 27 year old woman


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Transverse CT scan obtained with intravenous and oral contrast material reveals a

large, edematous, homogeneously attenuating (73-HU) pancreas (1) and

peripancreatic inflammatory changes (white arrows). Although the attenuation

values are low, there is no pancreatic necrosis. Calcified gallstones are seen ingallbladder (black arrow). 2= liver (140 HU).

Gallstone-induced pancreatitis in 27 year-old woman

Balthazar, E

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Infection?

Gallium-67 SPECT (perfusion studies)

? with (+) findings had infection atintervention 78% of all patients

No false (+)

No correlation between gallium uptake

and presence or absence of necrosis


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47-year-old man with severe pancreatitis

Fluid collection replacing pancreatic body and tail


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47-year-old man with severe pancreatitis

47-year-old man with severe pancreatitis who had true-positive finding for47-year-old man with severe pancreatitis who had true-positive finding for

infection on gallium study. Fusion image of CT scan and gallium study wasinfection on gallium study. Fusion image of CT scan and gallium study washelpful in localizing infection.helpful in localizing infection.


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Necrosis


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57-year-old man with acute necrotizing pancreatitis and severe back pain

Large region of unenhancement (necrosis) involving most of body and tail of

pancreas. Inflammatory fluid is present in anterior pararenal space. Noteascites around liver.

50 year-old woman with acute pancreatitis (1st view)


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50 year-old woman with acute pancreatitis (1st view)

(a, b) Transverse CT scans obtained with intravenous and oral contrast material reveal an

encapsulated fluid collection associated with liquefied necrosis (large straight arrows) in the body of

the pancreas. The head, part of the body, and the tail of the pancreas are still enhancing (smallstraight arrows). N= liquefied gland necrosis, S = stomach.

Balthazar

, EmilJ.

Radiology.20

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:603-613

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50 year-old woman with acute pancreatitis (2nd view)


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(a, b) Transverse CT scans obtained with intravenous and oral contrast material. The head,

part of the body, and the tail of the pancreas are still enhancing (straight arrows). Residual

fluid collections and areas of soft-tissue attenuation (curved arrow) consistent with fat necrosisare seen adjacent to the pancreas. f= fluid, N= liquefied gland necrosis.

50 year old woman with acute pancreatitis (2 view)

Baltha

zar,EmilJ.

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.2002;223

:603-613

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Complications


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Complications

Pancreatic Pseudocysts

Abscess

Hemorrhagic Pancreatitis Splenic Artery Pseudoaneurysm formation

or rupture/ Splenic Venous Thrombosis


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Pancreatic Pseudocyst

Fluid collection surrounded by fibrous

capsule but not lined by epithelium

Occurs in 10% of cases

Significant % will not resolve

spontaneously

Seen within pancreas and potentialspaces with which gland is continuous

(lesser sac and left pararenal space)

28 ld ith d t


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28 year-old man with pseudocyst

Image demonstrates a pseudocyst (arrow) in the tail of the pancreas

surrounded by a thick enhancing wall. The lesion appears

heterogeneous with central areas of higher attenuation, which is

suggestive of fresh hemorrhage. Note infiltration (arrowheads) of the

peripancreatic fat.

Cohen-Sca

li,Frack,

eta;.

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gy.2003;228

:727-733.

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44 year-old man with acute abdominal pain hemorrhagic pseudocyst


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Axial CT scan obtained with intravenous contrast material demonstrates calcifications

from chronic pancreatitis in the head of the pancreas. A high-attenuation focus of blood

(arrow) is seen within the low-attenuation pseudocyst, a finding that is consistent with

hemorrhage.

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Abscess

1 in 20 cases and fatal in of cases

Suspected clinically with fever and

septicemia

Pathognomonic finding presence of gas

bubbles in pancreatic bed

Pancreatic abscess containing gas in 54-year-old man


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Pancreatic abscess containing gas in 54-year-old man

Large fluid collection containing gas bubbles in pancreatic bed due to

abscess complicating acute pancreatitis. Note infiltration of

peripancreatic fat and calcified gallstones.


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Hemorrhagic Pancreatitis

Rare

Noted clinically by inhematocrit

70 year old woman with hemorrhagic pancreatitis


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CT scan demonstrates hemorrhagic pancreatitis as a heterogeneous mass in

the area of the pancreatic bed (*). Arrow indicates active extravasation(hemorrhage).

70 year-old woman with hemorrhagic pancreatitis

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Splenic Artery Pseudoaneurysm

Presents similarly to hemorrhagic

pancreatitis with a in hematocrit

Pseudoaneurysm


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Axial CT scan with intravenous contrast material reveals apseudoaneurysm (arrow) projecting from the splenic artery.

Pseudoaneurysm

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Management


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Management

Acute pancreatitis usually self-limited Inflammation within 3-7 days in 90% of

cases

Medical therapy Analgesics

IV hydration

Decrease PO intake Decreased pancreaticsecretion

Antimicrobials in severe necrotizingpancreatitis


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Presence of abscess or necrosis indicates

need for intervention

Percutaneous drainage of abscess

Surgical debridement (necrosectomy) of

infected necrotic tissue when conservative

treatment has failed

Management


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Prognosis


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Prognosis

Mortality over last 20 years

5% for all cases

20% for severe cases


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Reasons for Reduced Mortality

Initially - Recognition and application ofseverity signs

1990s More selective endoscopic orsurgical debridement of infected tissue,

endoscopic cyst drainage, andangiographic control of GI bleeding

Later Improved nutritional support by

jejunal feeding, earlier use of antibiotictherapy, gut sterilization, early ERCP forcommon bile duct stones, andnecrosectomy for necrotic tissue


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Resources

Resources


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Resources Balthazar, Emil J. Acute Pancreatitis: Assessment of Severity With

Clinical and CT Evaluation. Radiology. 2002; 223: 603-613.

Banu, S., P. Singh, N. Pooran, and B. Stark. Evaluation of FactorsThat Have Reduced Mortality from Acute Pancreatitis Over the Past

20 Years. Journal of Clinical Gastroenterology. 2002 July; 35: 50-

60.

Bennett, William F., Kuldeep Vaswani, and Kenneth Vitellas. Case

1: Parenchymal Lymphoma.American Journal of Roentgenology.2000; 175: 882-883.

Cohen-Scali, Frank, et al. Discrimination of Unilocular Macrocystic

Serous Cystadeoma from Pancreatic Pseudocyst and Mucinous

Cystadenoma with CT: Initial Observations. Radiology. 2003; 228:

727-733. Demos, Terrence C., et al. Cystic Lesions of the Pancreas.

American Journal of Roentgenology. 2002; 179: 1375-1388.

Gore, Richard M., et al. Helical CT in the Evaluation of the Acute

Abdomen.American Journal of Roentgenology. 2000; 174: 901-

913.

Resources Continued


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Resources Continued Gunderman, Richard B. Essential Radiology. 1998.

Greenberger, Norton J. and Phillip P. Toskes. Acute and Chronic

Pancreatitis. Harrisons Internal Medicine. Mitchell, RM, MF Byrne, and J. Baillie. Pancreatitis. Lancet. 2003

Apr 26; 361: 1447-1455.

Novelline, Robert A. Squires Fundamentals of Radiology. 6th ed.

2004.

Pretorius, E. Scott and Jeffrey A. Solomon. Radiology Secrets. 2nded. 2006.

Ranson, JH, et al. Prognostic Signs and the Role of Operative

Management in Acute Pancreatitis. Surgery, Gynecology, and

Obstetrics.

Tang, Linda J., Stan Zipser, and Young S. Kang. Temporary

Spontaneous Thrombosis of a Splenic Artery Pseudoaneurysm in

Chronic Pancreatitis During Intravenous Octreotide Administration.

Journal of Vascular Interventional Radiology. 2005; 16: 863-866.

R C ti d


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Resources Continued Urban, Bruce A. and Elliot K. Fishman. Tailored Helical CT

Evaluation of Acute Abdomen. Radiographics. 2000; 20: 725-749.

West, Jeffrey H., Stephen B. Vogel, and Walter E. Drane. Gallium

Uptake in Complicated Pancreatitis.American Journal of

Roentgenology. 2002; 178: 841-846.

ct imaging of acute pancreatitis

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