MBBCh MS FRCR Consultant radiologist Riyadh Military Hospital Dr Ahmed Refaey Normal CT anatomy of the upper abdomen Anterior pararenal space Normal Anatomy by CT Pancreas is located in the anterior ID: 908125
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Role of CT in acute pancreatitis
MBBCh, MS, FRCR
Consultant radiologist Riyadh Military Hospital
Dr. Ahmed
Refaey
Slide2Normal CT anatomy of the upper abdomen
Slide3Slide4Slide5Anterior pararenal space
Slide6Slide7Normal Anatomy by CTPancreas is located in the anterior pararenal space
Head adjacent to duodenumTail extending toward spleenSplenic vein posterior to body and tail
Slide8Normal Morphology by CTNo capsuleAP dimensions
Head 2-2.5 cm Body and tail 1-2 cmPancreatic duct Maximal diameter 3 mm in adults (5 mm in elderly)
Slide9Evaluation of Acute PancreatitisContrast-enhanced CT is imaging modality of choiceOral and IV contrast differentiate pancreatic tissue from adjacent blood vessels and duodenum
Slide10There is no additional value of an early CT (within 72 hours) in patients with acute pancreatitis. The diagnosis is usually made on clinical and laboratory findings.An early CT may be misleading concerning the severity of the pancreatitis, since it can underestimate the presence and amount of necrosis.
Slide11Etiology
Slide12PathophysiologyActivated pancreatic enzymes escaping the
ductal system and auto digesting the pancreas and adjacent structures ( mainly amylase, lipase & trypsin ).Lack of capsule facilitates spread
Slide13Acute pancreatitisMild acute pancreatitis ----- 80 %
* edematous ( interstitial ) * exudativeSevere acute pancreatitis ----20 %
Slide14Mild acute pancreatitis - run a mild course without development of multiple organ failure - improvement within 3 days following conservative therapy with gradual decrease of elevated enzymes.
- has a mortality rate of < 1%
Slide15Severe acute pancreatitis “ necrotizing “ - run a serious clinical course with pancreatic necrosis and the development of multiple organ failure
- of these, 60% of pancreatic necrosis remain sterile , while 40% becomes infected - this last category ( infected necrosis ) , has the highest mortality rate ( 25-70%)
Slide16Clinical outcome
Slide17CT Imaging of acute pancreatitis
Slide18Acute edematous “interstitial” pancreatitisAcute exudative pancreatitis
Mild acute pancreatitis
Slide19Acute edematous “interstitial” pancreatitis Edematous pancreas
with/without peripancreatic fat stranding. No collections or necrosis
Slide20Slide21Slide22Slide23Slide24Slide25Acute exudative pancreatitis
an intermediate form of pancreatitis without pancreatic necrosis with an intermediate clinical course.This is called extrapancreatic necrosis (EXPN)
Slide26Slide27Slide28Slide29Avoid early drainage of collections and avoid introducing infection! 50% of these collections show spontaneous regression The other 50% either remain stable (
pseudocyt ) or develop infection ( abscess ) .
Slide30Peripancreatic fluid50% spontaneous regression 50% stable
sterile ( pseudocyst) infection ( asbscess )
Slide31Spontaneous regression of peripancreatic collection
Slide32Severe pancreatitis “ necrotizing pancreatitis”
occurs in 20% of patients. * partial necrotizing pancreatitis * total necrotizing pancreatitis
Slide33Partial necrotizing Total necrotizingDelayed or no response to conservative therapy
Delayed or no normalization of enzymesMortality : 30 – 75 %Deterioration under conservative therapyMortality : 100 % - 40% by 2nd day - 75% by 5th day - 100% by 10th day
Slide34Slide35Slide36Slide37Slide38Slide39Slide40Central gland necrosis
Slide41Central gland necrosis
Subtype of necrotizing pancreatitis.Necrosis between the pancreatic head and tail and is nearly always associated with disruption of the pancreatic duct.This leads to persistent collections as the viable pancreatic tail continues to secrete pancreatic juices.These collections react poorly to endoscopic or percutaneous drainage.Definitive treatment often requires distal pancreatectomy
.
Slide42Slide43An early CT may be misleading concerning the severity of the pancreatitis, since it can underestimate the presence and amount of necrosis.
Slide44Slide45Slide46Mortality Early mortality in acute pancreatitis is the result of the systemic inflammatory response with multiple organ failure.
Late mortality is the result of infection of pancreatic necrosis and peripancreatic fluid collections which results in sepsis and is seen in more than 50% of deaths.
Slide47CT Severity IndexIt is critical to identify patients who are at high risk for severe disease, since they require close monitoring and possible intervention
Slide48Balthazar et al constructed a CT severity index (CTSI) for acute pancreatitis that combines the grade of pancreatitis (A-E) with the extent of pancreatic necrosis.
Slide49Slide50CT Severity Index1- 3 …………….. Mild 4-6 …………….. Moderate
7-10 ……………. Severe
Slide51Complications of pancreatits
Slide52ComplicationsPancreatic PseudocystsAbscess
Hemorrhagic PancreatitisSplenic Artery Pseudoaneurysm
Slide53Pancreatic PseudocystFluid collection surrounded by fibrous capsule
Time of onset : > 4 weeks from the onsetAmylase rich-fluidPrognosis : spontaneous resolution in 44%
Slide54Slide55Slide56Slide57AbscessWell demarcated fluid collection of pus Suspected clinically with fever and septicemia
Pathognomonic finding → presence of gasTime of onset : 2- 4 weeks after onset
Slide58Slide59Slide60Slide61Hemorrhagic pancreatitis Type of severe pancreatitisPeripancreatic fat necrosis and hemorrhage due to erosion of small vessels
Falling hematocrit Cullen sign and Grey-Turner sign
Slide62(Grey-Turner sign): flank ecchymosis
(Cullen sign) : periumbilical ecchymosisassociated with a 37% mortality rate
Slide63Grey Turner signCullen’s sign
Slide64Slide65Slide66Splenic Artery PseudoaneurysmPresents similarly to hemorrhagic pancreatitis with a
↓ in hematocrit
Slide67Slide68Slide69Take home messages
Slide70Severity of acute pancreatitis and pancreatic necrosis can only be reliably assessed by imaging after 72 hours. CT can not reliably differentiate between collections that consist of fluid and those that contain solid debris.In these cases MRI can be of additional value.
Slide71Central gland necrosis is a subtype of necrotizing pancreatitis with important implications. Avoid early drainage of collections and avoid introducing infection!
Slide72Thank you