急性胰腺炎影像学检查技术

Multi‐modality Imaging in  Acute Pancreatitis Marsha Lynch, HMS III Gillian Lieberman, MD BIDMC Core Clerkship in Radiology March 2009 Our Patient R: Introduction ¾52M with 10d history of nausea, vomiting and  abdominal pain. Patient R: Initial Presentation PRESENTATION • WBC 19.1 • ARF: Cr 3.2 (baseline 1.2) • BG: 235 • Lipase: 2211(0‐60) • Amylase: 804 (0‐100) • ALT:10  AST:9  AP:79 • Ca: 7.9 (8.4‐10.2) • TGs: 511 (0‐149) PMH • HTN • Hyperlipidemia • Congenital deafness • Gout • Obesity Patient R demonstrates a typical  presentation of acute  pancreatitis Acute Pancreatitis: Pathophysiology INFLAMMATION OF THE PANCREAS • Inappropriate activation of pancreatic enzymes • Intraparenchymal and extraparenchymal extravasation of enzymes cause autodigestion of pancreatic  parenchyma and damage to peripancreatic tissues and  vascular network • Inflammatory response to this injury out of proportion  to that of other organs to a similar insult • Inflammatory response causes further damage – Fluid sequestration, fat necrosis, vasculitis leading to  occlusions and thrombosis, hemorrhage Whitcomb, D C, Acute Pancreatitis. N Engl J Med 2006 Balthazar, E J, Acute Pancreatitis: Assessment of Severity with Clinical and CT Evaluation. Radiology 2002 Acute Pancreatitis: Etiologies Etiologies of Acute Pancreatitis Mechanical Gallstones (>45%) , sludge, pancreatic mass, ampullary stenosis or  mass ,duodenal stricture or obstruction  Toxic Alcohol (>35%), methanol, steroids/ drugs, scorpion venom Metabolic Hyperlipidemia, hypertriglyceridemia, hypercalcemia Trauma Blunt or penetrating, ERCP, s/p abdominal surgery Infection Viral (mumps), parasitic, bacterial Vascular Ischemia, embolism, vasculitis Congenital Pancreas divisum Genetic CFTR mutation Miscellaneous Autoimmune, renal transplant, alpha‐1‐anti‐trypsin deficiency Adapted from “etiology of acute pancreatitis”; Up-To-Date Acute Pancreatitis: Epidemiology • >200,000 US hospital  admission yearly • 20% have a severe  course – Associated with systemic  and local complications  and increased mortality  (10‐30%) • Severe Course ¾ SYSTEMIC  COMPLICATIONS • Shock • DIC • Pulm. Insufficiency/ARDS ¾ LOCAL COMPLICATIONS • Necrosis • Abscess • Pseudocyst • Pseudoaneurysm • Splenic vein thrombosis Acute Pancreatitis: Severity  Assessment Severity of acute pancreatitis is commonly assessed using : 1. Ranson’s Criteria – 5 clinical signs at presentation and 6 at 48hrs – ≥ 3 associated with severe course (systemic complications and/or  pancreatic necrosis) 2. APACHE II – 12 routine physiologic measurement, age and previous health status – ≥ 8 associated with severe course 3. CT Severity Index (CTSI) – Based on extent of inflammation and presence of complications on CT scan. Let’s briefly review the anatomy  of the pancreas Pancreas Anatomy Retroperitoneal organ stretching from the curvature of the duodenum to the spleen. Rich arterial supply from vessels off the celiac artery superiorly and the SMA inferiorly. Glandular tissue with both endocrine and exocrine function. http://www.fairview.org/healthlibrary/content/pancreas.gif Pancreas Anatomy: Axial CT View Image from: PACS, BIDMC pancreas pancreas Companion Patient 1: Delayed Phase Axial CT Acute Pancreatitis CLINICAL DIAGNOSIS • Abdominal pain • Nausea/Vomiting • Elevated Pancreatic  Enzymes MANAGEMENT • Bowel Rest/NPO • IVF • Analgesics http://www.fairview.org/healthlibrary/content/pancreas.gif The diagnosis of pancreatitis is largely a  clinical one based on physical signs and  symptoms as well as serum levels of  pancreatic enzymes.  What then is the role of Radiology in its  management? Role of Radiology in Acute Pancreatitis • Rule out other intra‐abdominal conditions as  cause of abdominal pain or other symptoms – Bowel obstruction, infarction or perforation; acute cholecystitis;  appendicitis • Confirm diagnosis and Identify causes (e.g.  gallstones) • Evaluate and stage local pancreatic morphology • Identify and manage complications • Menu of Tests: US, Plain Film, CT, MR Back to Our Patient R Patient R: Ranson’s Criteria ¾ Ranson’s Score ≥ 3 (Threshold) • At Presentation – Age > 55 – BG > 200 – WBC > 16,000 – LDH > 350 – ALT > 250 • Within 48 Hours – Hct > 10% decrease – Serum Ca < 8 – Base Def > 4 – BUN > 5 increase – Fluid Sequestration > 6L – PaO2 < 60 ¾ PATIENT X PRESENTATION – WBC 19.1 – BG 235 – Age 52 – ALT 10 – LDH 15 We are less concerned about our patient  progressing down an more severe path based  on him having only 2/5 Ranson’s criteria at  presentation. However, we can use radiology to assess  whether his acute pancreatitis is due to one  of the commonest etiologies: gallstones.  We therefore proceed to abdominal  Ultrasound… Use of Abdominal Ultrasound in  Acute Pancreatitis Indicated early in acute pancreatitis ¾ Pros – Inexpensive – Excellent for identifying gallbladder pathology, sludge and gallstones  (Most common cause of pancreatitis!) – Evaluate bile‐duct dilation – May visualize  masses and follow up of pseudocyst ¾ Cons – Not optimal for pancreas; retroperitoneal location easily obscured by  bowel gas distension – Less sensitive for stones in distal CBD – Limited in early assessment of pancreatitis Balthazar, E J, Acute Pancreatitis: Assessment of Severity with Clinical and CT Evaluation. Radiology 2002 Patient R Abdominal US: Liver,GB Image from: PACS, BIDMC Gallbladder: anechoic cystic region with increased through- transmission Liver parenchyma: no gross intra-hepatic ductal dilitation Abdominal Ultrasound: RUQ Patient R Abdominal US: GB Image from: PACS, BIDMC Absence of hyperechoic foci Non-distended GB with normal wall thickness No signs of acute cholecyctitis: lack of gallbladder wall thickening, pericholecystic fluid or cholelithiasis Abdominal Ultrasound: RUQ Happily, our suspicion of gallbladder  pathology as the cause of our patient R’s  acute pancreatitis is now greatly lowered. So we continue supportive  management with bowel rest, IVF  and analgesics. On Hospital Day 5… …our Patient R develops bowel  distension and abdominal pain. We proceed immediately to  Abdominal Plain Film Use of Abdominal Plain Film in  Acute Pancreatitis ¾ Pros – Screen for/exclude separate or accompanying abdominal process • Signs of peritonitis or bowel ischemia – Free air • Bowel Obstruction • Ascites – Inexpensive, readily available and fast ¾ Cons – Poor visualization of the pancreas and retroperitoneum • May see calcifications due to chronic process Patient R:  Abdominal  Plain Film HD 5 Image from: PACS, BIDMC residual contrast in asc. and desc. colon ----- isolated segments of dilated sm. bowel, up to 3cm luminal diameter Transverse colon shows no marked distention but with no contrast Abdominal Plain Film: Supine spasm of the desc. colon just distal to splenic flexure Patient R  Abdominal  Plain Film HD 5 Image from: PACS, BIDMCAbdominal Plain Film: L Lat Decubitus Air fluid levels The presence of distension in the along with  air‐fluid levels concern us for small bowel  obstruction. We decide to closely follow our  patient. On Hospital Day 6… Our patient has worsening  abdominal pain and distension. We  quickly perform a repeat abdominal  plain film. Patient X  Abdominal  Plain Film HD 6 3.3 cm 8.5 cm Distended stomach Increased focal distension of small bowel Abdominal Plain Film: Supine Image from: PACS, BIDMC Marked distension of transverse colon, still with no contrast in lumen. arrest of contrast (2 days) We are certainly more concerned about   obstruction now. Before we continue, let’s  review some possible causes of obstruction in  this patient. Possible Causes of Bowel  Obstruction in Our Patient R • Functional  – Focal ileus/Sentinel loops (Transverse colon and  segments of small bowel) due to adjacent  pancreatic inflammatory process • Mechanical – Pancreatic mass • Developing fluid collections or pseudocyst • GB unseen on U/S We are more concerned about yet unseen  causes of any mechanical obstruction.  We now proceed to Abdominal CT to further  evaluate the cause of the increasing  abdominal distension and to have a better  look at the inflamed pancreas. Use of Abdominal CT in Acute  Pancreatitis ¾ Pros – Readily available and Fast – Aid in diagnosis and staging of pancreatitis – Depict, quantify pancreatic parenchymal injury • Ability to assess the presence or absence of: – Edema (focal or diffuse) – Peripancreatic fluid and inflammation – Fluid collections – Pseudocysts – Necrosis  – Evaluate common bile duct for stones or other obstructions ¾ Cons – Our Patient R is in ARF and this may be exacerbated by IV contrast  administration Patient R Delayed‐Phase axial CT:  Supra‐pancreatic fluid collection Image from: PACS, BIDMC 4x7cm fluid collection just superior to the pancreas Delayed Phase CT: Axial Normal vs. Acute Pancreatitis Images from: PACS, BIDMC Acute pancreatitis: swollen, edematous gland with indistinct edges blurred into those of surrounding structures Axial Delayed Phase CT: Companion Pt. 1 Axial Delayed Phase CT: Patient R Normal pancreas: Fluffy, macronodular gland texture distinct from surrounding organs Patient R: Abdominal CT ‐ peripancreatic fat stranding and  patent splenic vein peripancreatic fat stranding patent splenic vein Axial Delayed Phase CT: Patient RAxial Delayed Phase CT: Patient R Images from: PACS, BIDMC Patient R Abdominal CT: Focal  Transverse Ileus and Arrest of  Contrast arrest of contrast adynamic transverse colon Axial Delayed Phase CT: Patient RAxial Delayed Phase CT: Patient R Images from: PACS, BIDMC Patient R Abdominal CT:  Suspicious hyperattenuating lesion There is a round hyperdensity measuring 1.4cm with similar attenuation as the adjacent aorta. We can also visualize the IVC posterior and the GDA adjacent and just superior to the lesion. This could represent: 1.Pseudoaneurysm of GDA 2.Gallstone 3.Reactive lymph node. Image from: PACS, BIDMCDelayed Phase CT: Axial What Now??? We need to further explore this lesion as our  last study was limited by the lack of both a  non‐contrast  and arterial phase. Luckily, we have another tool in our arsenal. Use of MR in Acute Pancreatitis Increasingly used in diagnosis and management of acute pancreatitis ¾ Pros – Non‐invasive and no use of IV contrast – Ability to better characterize fluid collections (acute collection vs.  abscess, necrosis, hemorrhage, pseudocyst) – Ability to delineate pancreatic and bile ducts (detect  choledocholithiasis missed on U/S ) and other complications  comparable to ERCP – Greater sensitivity vs. CT in detecting mild pancreatitis ¾ Cons – Expensive and in many less severe cases not necessary for diagnosis  and management – Less readily available in non‐tertiary medical centers Patient R: Abdominal MR Image from: PACS, BIDMCT2 MRI: flow-void sequence Our lesion has high signal distinct from the absence of signal (flow-void sequence) in the other three vessels of interest: GDA, IVC and aorta. In particular, the lesion is distinct from the GDA, significantly reducing our suspicion for pseudoaneurysm. Patient R: High signal lesion on MR In this sequence, gallstones would demonstrate no signal and our lesion is consistent with a reactive lymph node. Image from: PACS, BIDMCT2 MRI: flow-void sequence Patient R: Comparison of CT versus  MRI findings The suspicious lesion on CT was further evaluated on MR and found to be benign consistent with a reactive lymph nose Images from: PACS, BIDMC T2 MR: flow-void sequenceDelayed Phase CT: Axial A word about Pleural Effusions… Pleural Effusions: a common  complication of Acute Pancreatitis Approx. 1/3 patients with acute pancreatitis will have will have abnormal CXRs. The typical findings include elevated hemidiaphragm, pleural effusions, atelectasis and in more severe cases ARDS Patient R: Delayed Phase CT Low lung volumes, Bibasilar atelectasis and pleural effusions Images from: PACS, BIDMC Patient R: Frontal CXR Patient R: Lateral CXR Patient R: Remaining Course • HD 6 – Emesis and large BM that largely relieved abdominal pain • Started on TPN – Diet slowly advanced until tolerated regular diet • Continued on supportive measures as labs  normalized and symptoms resolved • Discharged to Home on HD 16 Patient R Remaining Course cont’d PRESENTATION • WBC 19.1 • ARF: Cr 3.2 (baseline 1.0) • BG: 235 • Lipase: 2211(0‐60) • Amylase: 804 (0‐100) • ALT:10 (0‐40) • AST:9 (0‐40) • AP:79 (39‐117) • Ca: 7.9 (8.4‐10.2) • TGs: 511 (0‐149) DISCHARGE • WBC 7.4 • Cr 0.9  • BG: 95 • Lipase: 59*(0‐60) • Amylase: 50* (0‐100) • ALT:18   • AST:29   • AP:79* • Ca: 8.7 (8.4‐10.2) • TGs: 112 (0‐149) * Last labs drawn before date of discharge Summary • Acute Pancreatitis is a common illness with  many potential highly morbid complications. • Many cases are diagnosed clinically and  managed supportively with bowel rest,  aggressive fluid administrations and analgesics. • Radiology plays important role in confirming  diagnoses, evaluating severity and identifying   and managing complications of acute  pancreatitis. References • Whitcomb, D C, Acute Pancreatitis. N Engl J Med  2006;354:2142‐50. • Balthazar, E J, Acute Pancreatitis: Assessment of  Severity with Clinical and CT Evaluation. Radiology  2002; 223:603– 613 • Textbook of Gastrointestinal Radiology / [edited by] Richard M. Gore, Marc S. Levine. London : W. B. Saunders Co., c2000. • Up-To-Date, ‘Clinical manifestations and diagnosis of acute pancreatitis’, ‘etiologies of acute pancreatitis’ Acknowledgements • Ernest Yeh, MD • Maria Levantakis, Course Co‐ordinator • Gillian Lieberman, MD Multi-modality Imaging in �Acute Pancreatitis Our Patient R: Introduction� Patient R: Initial Presentation Patient R demonstrates a typical presentation of acute pancreatitis Acute Pancreatitis: Pathophysiology Acute Pancreatitis: Etiologies Acute Pancreatitis: Epidemiology Acute Pancreatitis: Severity Assessment Let’s briefly review the anatomy of the pancreas Pancreas Anatomy Pancreas Anatomy: Axial CT View Acute Pancreatitis The diagnosis of pancreatitis is largely a clinical one based on physical signs and symptoms as well as serum levels of pancreatic enzymes. ��What then is the role of Radiology in its management? Role of Radiology in Acute Pancreatitis Back to Our Patient R Patient R: Ranson’s Criteria We are less concerned about our patient progressing down an more severe path based on him having only 2/5 Ranson’s criteria at presentation. However, we can use radiology to assess whether his acute pancreatitis is due to one of the commonest etiologies: gallstones. Use of Abdominal Ultrasound in Acute Pancreatitis Patient R Abdominal US: Liver,GB Patient R Abdominal US: GB Happily, our suspicion of gallbladder pathology as the cause of our patient R’s acute pancreatitis is now greatly lowered. On Hospital Day 5… Use of Abdominal Plain Film in Acute Pancreatitis Patient R: Abdominal �Plain Film�HD 5 Patient R Abdominal Plain Film�HD 5 The presence of distension in the along with air-fluid levels concern us for small bowel obstruction. We decide to closely follow our patient. On Hospital Day 6… Slide Number 29 We are certainly more concerned about obstruction now. Before we continue, let’s review some possible causes of obstruction in this patient. Possible Causes of Bowel Obstruction in Our Patient R We are more concerned about yet unseen causes of any mechanical obstruction. �We now proceed to Abdominal CT to further evaluate the cause of the increasing abdominal distension and to have a better look at the inflamed pancreas. Use of Abdominal CT in Acute Pancreatitis Patient R Delayed-Phase axial CT: Supra-pancreatic fluid collection Normal vs. Acute Pancreatitis Patient R: Abdominal CT - peripancreatic fat stranding and patent splenic vein Patient R Abdominal CT: Focal Transverse Ileus and Arrest of Contrast Patient R Abdominal CT: �Suspicious hyperattenuating lesion What Now???�We need to further explore this lesion as our last study was limited by the lack of both a non-contrast and arterial phase.�Luckily, we have another tool in our arsenal. Use of MR in Acute Pancreatitis Patient R: Abdominal MR Patient R: High signal lesion on MR Patient R: Comparison of CT versus MRI findings A word about Pleural Effusions… Pleural Effusions: a common complication of Acute Pancreatitis Patient R: Remaining Course Patient R Remaining Course cont’d Summary References Acknowledgements