CT Imagine of Acute Pancreatitis

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  • Cholelithiasis > in women
    Alcohol > in men
    Iatrogenic – secondary to hypersensitivity of toxic metaboite (i.e.steroids, thiazide diuretics, anti-retrovirals, estrogens, tetracycline, etc.)
    Surgery – Abdominal or cardiac (i.e. 5-20% after ERCP)
    Metabolic disorders – 1-4% with hyperlipidemia (>1000 mg/dL) or hypercalcemia
    Viral Infection – mumps or CMV
  • Portal vein confluence = splenic vein + superior mesenteric vein
  • Tapers slightly from head to tail
  • Classic presentation – epigastric or periumbilical pain that is worse when supine & radiates to back, chest, and flanks, N/V, and abdominal distention
    Physical Exam – low grade fever. tachycardia, hypotension, jaundice, erythematous skin nodules from subcutaneous fat necrosis, pulmonary findings such as pulmonary effusions >L, basilar rales, and atelectasis, abdominal tenderness and rigidity, and discoloration (Cullen’s sign – blue discoloration around umbilicus from hemoperitoneum; Turner’s sign – blue-red-purple or green-brown discoloration at flanks from tissue catabolism of hemoglobin)
  • Fluid collections:
    Phlegmon – large inflammatory mass of pancreatic and peripancreatic tissues
    Abscess, pseudocyst, hemorrhage, or ascites
  • Lesser sac – between pancreas and stomach
  • Best seen on CT but can even be noted on plain abdominal films when copious amounts of gas are present
  • Enteral feeding is currently preferred over parenteral feeding
  • Decreased from 10-15% for all cases and up to 90% for severe cases
  • 1) i.e. Ranson’s criteria which determines ICU admission and close follow-up
  • CT Imagine of Acute Pancreatitis

    1. 1. CT Imaging of Acute Pancreatitis Erin Rikard Radiology December 2007
    2. 2. Outline • Definition • Epidemiology • Causal Factors • Pathophysiology • CT Evaluation and Findings – Normal and abnormal • Complications • Management • Prognosis
    3. 3. Definition
    4. 4. Definition AcutePancreatitis - Inflammation of pancreas with potential for complete healing
    5. 5. Epidemiology
    6. 6. Epidemiology • 79.8/100,000 per year → 185,000 new cases annually in U.S. • Peak incidence in 6th decade
    7. 7. Causal Factors
    8. 8. Causal Factors Etiology Incidence Cholelithiasis 30-60% Alcohol 15-30% Iatrogenic 2-5% Trauma/Surgery -- Metabolic Disorders -- Viral Infection --
    9. 9. Pathophysiology
    10. 10. Pathophysiology • Pancreatic autodigestion, with activated pancreatic enzymes escaping the ductal system and lysing tissue of pancreas and adjacent structures • Lack of capsule facilitates spread
    11. 11. Normal CT Findings
    12. 12. 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
    13. 13. 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
    14. 14. Copyright©2007bytheAmericanRoentgenRaySociety Bennett,W.F.etal.Am.J.Roentgenol.2000;175:882-883 50 year-old woman CT scans of normal kidneys and pancreas Spleen L KidneyR Kidney A Stomach Liver V Pancreas
    15. 15. Evaluation by CT
    16. 16. 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
    17. 17. 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
    18. 18. 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
    19. 19. Abnormal CT Findings
    20. 20. • Peripancreatic inflammation • Diffuse or focal pancreatic edema • Poor definition and heterogeneity of gland • Fluid collections • Necrosis • Thickening of pararenal fascia Abnormal CT Findings
    21. 21. Spectrum of Disease • Mild Cases  May be normal or show only mild gland enlargement • Severe Cases  May reveal peripancreatic fluid &/or pancreatic necrosis and phlegmon
    22. 22. Peripancreatic Inflammation/ Pancreatic Edema/ Fluid Collections
    23. 23. 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 in gallbladder (black arrow). 2 = liver (140 HU). Gallstone-induced pancreatitis in 27 year-old woman Balthazar,EmilJ.Radiology.2002;223:603-613 Copyright©2002byRSNA
    24. 24. Infection? • Gallium-67 SPECT (perfusion studies) • ? with (+) findings had infection at intervention – 78% of all patients • No false (+) • No correlation between gallium uptake and presence or absence of necrosis
    25. 25. Copyright©2007bytheAmericanRoentgenRaySociety West,J.H.etal.Am.J.Roentgenol.2002;178:841-846 47-year-old man with severe pancreatitis Fluid collection replacing pancreatic body and tail
    26. 26. Copyright©2006bytheAmericanRoentgenRaySociety West,J.H.etal.Am.J.Roentgenol.2002;178:841-846 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 was helpful in localizing infection.helpful in localizing infection.
    27. 27. Necrosis
    28. 28. Copyright©2006bytheAmericanRoentgenRaySociety Gore,R.M.etal.Am.J.Roentgenol.2000;174:901-913 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. Note ascites around liver.
    29. 29. 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 (small straight arrows). N = liquefied gland necrosis, S = stomach. Balthazar,EmilJ.Radiology.2002;223:603-613 Copyright©2002byRSNA
    30. 30. (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 necrosis are seen adjacent to the pancreas. f = fluid, N = liquefied gland necrosis. 50 year-old woman with acute pancreatitis (2nd view) Balthazar,EmilJ.Radiology.2002;223:603-613 Copyright©2002byRSNA
    31. 31. Complications
    32. 32. Complications • Pancreatic Pseudocysts • Abscess • Hemorrhagic Pancreatitis • Splenic Artery Pseudoaneurysm formation or rupture/ Splenic Venous Thrombosis
    33. 33. 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 potential spaces with which gland is continuous (lesser sac and left pararenal space)
    34. 34. 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-Scali,Frack,eta;.Radiology.2003;228:727-733. Copyright©2003byRSNA
    35. 35. 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. 44 year-old man with acute abdominal pain – hemorrhagic pseudocyst Urban,BruceA.,etal.Radiographics.2000;20:725-749. Copyright©2000byRSNA
    36. 36. Abscess • 1 in 20 cases and fatal in ¾ of cases • Suspected clinically with fever and septicemia • Pathognomonic finding → presence of gas bubbles in pancreatic bed
    37. 37. Copyright©2006bytheAmericanRoentgenRaySociety Demos,T.C.etal.Am.J.Roentgenol.2002;179:1375-1388 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.
    38. 38. Hemorrhagic Pancreatitis • Rare • Noted clinically by ↓ in hematocrit
    39. 39. 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 Urban,BruceA.,etal.Radiographics.2000;20:725-749. Copyright©2000byRSNA
    40. 40. Splenic Artery Pseudoaneurysm • Presents similarly to hemorrhagic pancreatitis with a ↓ in hematocrit
    41. 41. Axial CT scan with intravenous contrast material reveals a pseudoaneurysm (arrow) projecting from the splenic artery. Pseudoaneurysm Tang,LindaJ.JVascIntervRadiol.2005;16:863-866 Copyright©2005byTheSocietyofInterventionalRadiology
    42. 42. Management
    43. 43. Management • Acute pancreatitis usually self-limited  Inflammation ↓ within 3-7 days in 90% of cases • Medical therapy  Analgesics  IV hydration  Decrease PO intake → Decreased pancreatic secretion Antimicrobials in severe necrotizing pancreatitis
    44. 44. • 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
    45. 45. Prognosis
    46. 46. Prognosis • Mortality ↓ over last 20 years  5% for all cases 20% for severe cases
    47. 47. Reasons for Reduced Mortality • Initially - Recognition and application of severity signs • 1990s – More selective endoscopic or surgical debridement of infected tissue, endoscopic cyst drainage, and angiographic control of GI bleeding • Later – Improved nutritional support by jejunal feeding, earlier use of antibiotic therapy, gut sterilization, early ERCP for common bile duct stones, and necrosectomy for necrotic tissue
    48. 48. Resources
    49. 49. 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 Factors That 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.
    50. 50. Resources Continued • Gunderman, Richard B. Essential Radiology. 1998. • Greenberger, Norton J. and Phillip P. Toskes. “Acute and Chronic Pancreatitis.” Harrison’s Internal Medicine. • Mitchell, RM, MF Byrne, and J. Baillie. “Pancreatitis.” Lancet. 2003 Apr 26; 361: 1447-1455. • Novelline, Robert A. Squire’s Fundamentals of Radiology. 6th ed. 2004. • Pretorius, E. Scott and Jeffrey A. Solomon. Radiology Secrets. 2nd ed. 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.
    51. 51. 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.

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