MDCT in Acute Pancreatitis Nordic Forum ... - radiographia.ru

Nordic Forum - Trauma & Emergency RadiologyMDCT in Acute PancreatitisBorut MarincekInstitute of Diagnostic RadiologyUniversity Hospital Zurich, SwitzerlandAcute Pancreatitis (AP)EtiologiesMechanical (choledocho-/microlithiasis, ampullary/periampullary obstruction, anatomic variant, trauma),toxic-metabolic (alcohol, hyperlipidemia, hypercalcemia),vascular, infectious (viruses, bacteria, fungi, parasites),drug relatedMost common: gallstone disease & alcohol abuse (~70%)ClassificationThe 1992 Atlanta, Ga, International Symposium• based on clinical and morphological criteria• mild and severe AP (Bradley, Arch Surg 1993)

AP: Mild Form70-80% of all patientsMorphologyInterstitial edema, micronecrosisClinical courseResponds to supportive therapy, improve in 48-72 hrsNo organ failureImagingNONEUS to evaluate gallstones & dilatation of CBDAP: Severe Form20-30% of all patientsMorphologyLarge confluent necrosis, hemorrhageClinical courseRequires intensive monitoring & specific therapiesAssociated with local (pseudocyst, abscess, infectednecrosis) & extrapancreatic complicationsOrgan failure (renal and pulmonary most common)Pulmonary or pleural alterations: sens/spec60/88% for presence of necrosis73/75% for presence of infected necrosis90/76% for mortality rate (Pezzilli, Hepatogastroenterology 1998)

AP: Imaging EvaluationContrast-enhanced CT = imaging modality of choiceMild AP:• Interstitial edema slight pancreas enlargement• Intrapancreatic fatty tissue necrosis heterogeneity of pancreatic parenchyma• Exudates, slight peripancreatic fatty tissuenecrosis or hemorrhage in various combinations blurred organ contours; peripancreatic fluidcollections, thickened fasciaMild AP• Peripancreatic fluid collection: enzyme rich pancreaticjuice• Lacks wall, occurs within 48 hrs in 30-50%• Resolves spontaneously 50%

Mild APEtiology: hyperlipidemiaSlight pancreas enlargementPeripancreatic fluidcollection, thickened fasciaMild APClinical question: ruptured AAA? History: 5 days afterlaparoscopic cholecystectomy ( gallstone causing APlikely)

Mild APERCP April 20, laparoscopic cholecystectomy April 26for gallstones and acute cholecyszitisApril 23 April 28AP: Indications for CTCT evaluation of patients with• Clinical diagnosis in doubt• Failure to improve within 72 hrs of initialconservative medical treatment• Clinical deterioration, early recognition of seriouscomplications• Guidelines for assessment by CT:UK Working Party on AP (Gut 2005;54:1-9)JPN Guidelines (J Hepatobiliary Pancreat Surg 2006;13:33-41)

AP: Imaging EvaluationSevere AP:• Extensive peripancreatic fatty tissue necrosis,exudations, slight hemorrhage extensiveperipancreatic fluid collections• Parenchymal necrosis enhancement 30% of pancreas or >3 cm in diameter(Bradley, Arch Surg 1993)Severe APPotential pitfall oncontrast-enhanced CT:necrosis may not beapparent up to 48 hrsafter onset pancreatic necrosis more likely pancreaticduct disrupted8 dayslater

Severe APDec 3: endoscopy & biopsyof papilla Vateri ( biliaryobstruction?), no malignancyDec 4CT shortcoming: inability todifferentiate fluid collection -extrapancreatic fatty tissuenecrosisDec 17Severe APExtension of pancreatitisfluid collections:compression butpreservation of fat inposterior pararenal space

Severe APHistory of alcohol abuseSevere APDec 24Jan 1Heterogeneous enhancement& nonenhancingnecrotic areas of pancreas

Severe APStaging AP: CT Severity Index (CTSI)• CTSI (10-point severity scale) based on degree ofpancreatic inflammation and necrosis (Balthazar, Radiology1990; Balthazar, Radiology 1994)• CTSI correlates with morbidity and mortality, but notwith development of organ failure or peripancreaticcomplications• Modified CTSI (by simplifying scoring forinflammation and necrosis, adding weight factor forextrapancreatic complications, using MDCT)correlates more closely with patient outcomemeasures, with similar interobserver variability(Mortele, AJR 2004)

Staging AP: Modified CTSI1. Image analysis:2. Outcome parameters: length of hospital stay, need forsurgical or percutaneous procedures, occurence ofinfection, development of organ failure (Mortele, AJR 2004)CT Assessment of Severity of AP• Accuracy of CTSI for predicting pancreatitis severitysignificantly higher than APACHE II (AcutePhysiology and Chronic Health Evaluation,monitoring system based on 12 physiologicmeasurements) and C-reactive protein (Gurleyik, Pancreas2005)• Reliable method, widely available; patients with CTSI

MRI in APMRI as efficient as CT in recognizing necrosis andpredicting severity (Arvanitakis, Gastroenterology 2004)Sensitivity of MRI may surpass CT (minorperipancreatic inflammation) on T2w images(Pamuklar, Magn Reson Clin NA 2005)Advantages MRI:- less nephrotoxicity of contrast medium (potentialfor extension of necrosis and exacerbation of renalimpairment after iv iodine contrast media?)- allows evaluation of pancreatic duct & biliarysystem using MRCPMRI in APKnown biliary stonesMinor peripancreaticinflammation

AP: Complications1. Pseudocyst2. Abscess3. Infected necrosis4. Extrapancreatic: spontaneous fistulization, gastricoutlet obstruction, intestinal necrosis, bleedingpseudoaneurysm, splenic vein thrombosisPseudocyst• Collection of pancreatic fluid contained by granulationtissue CT: well circumscribed, thin walled, lowattenuation collection• Develops as a consequence of AP in patients withperipancreatic fluid collections, pancreatic necrosis, orchronic pancreatitis• Requires usually >4 weeks from onset of acuteepisode(Baert, 1995)

Pseudocyst• Adjacent to, occasionally within the pancreas• Resolves spontaneously within 6 weeks 40%,80% if

Pseudocysts and MalignancyNon-Hodgkin-LymphomaAmylase and lipase AP secondary to tumorcompression of pancreatic ductor direct tumor infiltrationPancreatic Duct Injury: Posttraumatic Pseudocyst14 yo, f: epigastric pain2 days after fall during trampoline jumpingJan 25Feb 13Feb 16

The cystic lesion shown is a .... (37 yo, f)Intermittent attacks of colicky epigastric painUS diagnosis: large cystic lesion in the liver hilus Pancreatic Pseudocyst ?

Choledochal Cyst Type 1Choledochal Cysts: Todani-ClassificationType 1ACystic dilatation(80-90%)Type 1BFocal segmentaldilatationType 1CFusiform dilatationType 2DiverticulumType 3Choledochocele(rarest type)Type 4AIntra-and extrahepaticsegmentalcystic dilatationsType 4BExtrahepaticsegmental cysticdilatationsType 5Intrahepatic segmentalcystic dilatations(Caroli‘s disease)

Pancreatic Pseudocyst - Interventions• Criteria:- symptomatic cyst with pain, infection, or compressionof adjacent organs- diameter >6 cm• Techniques:- endoscopic (transgastric or transduodenal)- percutaneous- surgicalPseudocyst: Transgastric DrainageJan 18 Feb 9

AbscessEncapsulated collection of pus, usually in proximity to butoutside of pancreas; in 3% of patients with peripancreaticfluid collectionsCT: wall thicker ormore irregular thanwall of pseudocystAbscess: CT-guided DrainageMortality risk for infected necrosis = double that forpancreatic abscess (Freeny, AJR 1998)

Infected Pancreatic Necrosis• Most serious local complication of AP• 30-70% of patients with pancreatic necrosis• 2nd – 3rd week following onset of severe AP• Typically polymicrobial, E. coli in about 35% sourceof contamination = particularly colon translocationof bacteria directly through intestinal wall• Detection of gas bubbles in necrotic tissue indicativeof infective necrosis (extraluminal retroperitoneal gascaused by intestinal fistula very rare)• Surgical strategy: necrosectomyMore recently: percutaneous CT-guided catheterdrainage (Freeny, AJR 1998) or laparoscopic-assistedpercutaneous drainage (Horvath, Surg Endosc 2001; Haan, Am Surg2006)Pseudocyst & Infected NecrosisCBD-obstructing pseudocyst pancreatic head stentInfected pancreatic & peripancreatic necrosisMay 7 May 31

Infected Necrosis Pancreatic HeadInfected Necrosis: CT-Guided DrainageJan 12 Jan 19

AP: Extrapancreatic ComplicationSpontaneous fistulization, oral contrast agentAP: Extrapancreatic ComplicationPseudoaneurysm of gastroduodenal/gastroepiploic artery(after rupture into preexisting pseudocyst or digestion ofarterial wall by enzymes)

AP: Extrapancreatic ComplicationNon-occlusive mesenteric ischemia (NOMI) and associatedintestinal gangrenePrevalence / mortality (N=120):NOMI 6.7% / 63%NOMI-associatedintestinal gangrene 4.2% / 100%(Hirota, Pancreatology 2003)AP: Extrapancreatic ComplicationSplenic vein thrombosis in 1-3% following pancreatitisSVCVSVPseudocyst & stenosis splenic vein (SV) collaterals via coronary vein (CV, hepatopetal flow),gastric fundal varices left-sided portal hypertension

MDCT in AP: Conclusions• Contrast-enhanced CT: primary imaging modalityfor assessing the severity of AP and for follow-up• MDCT has changed the traditional Balthazar scorein assessing the severity of AP• MRI is the best alternative in patients withcontraindications for CT• Optimal time for performance of a CT examinationto assess the early phase of AP is not yet defined