Pancreatitis... scoring and new atlanta terms

Dr/Ahmed Bahnassy

Consultant radiologist

causes and outcomes

Imaging

An early CT may be misleading concerning the severity of the pancreatitis, since it can underestimate the presence and amount of necrosis.Early CT is only recommended when the diagnosis is uncertain, or in case of suspected early complications such as perforation or ischemia.

golden rule

too early CT misleading exam

Alcoholic pancreatitis

The widespread clinical practice of relying solely on hyperamylasemia to establish the diagnosis of acute alcoholic pancreatitis is unjustified and should be abandoned.

Serum lipase was measured in 65 of these normoamylasemic cases and was found to be elevated in 68%.thus increasing diagnostic sensitivity from 81% when amylase alone is used to 94% for both enzymes.

special issue

scoring of severity

code with physician

Interstitial pancreatitis

there is normal enhancement of the entire pancreatic gland with only mild surrounding fatty infiltration. There are no fluid collections or necrosis (Balthazar grade C, CTSI: 2).

Exudative PancreatitisIn exudative pancreatitis, or better called EXPN, there is normal enhancement of the entire pancreas associated with extensive peripancreatic collections. These are often heterogeneous in appearance and may be progressive. EXPN consists of necrosis of peripancreatic fat, extravasated pancreatic fluid and inflammatory and hemorrhagic components.When peripancreatic collections persist or increase, it is usually due to the presence of fat necrosis (i.e. EXPN).Since fat does not enhance on CT, we cannot diagnose fat necrosis.

on day 18 there is expansion of the peripancreatic collections.There are two or more collections, but no pancreatic necrosis.(Balthazar grade E, CTSI: 4)

Necrotizing Pancreatitis

There are 2 or more fluid collections and more than 50% of the gland does not enhance (Balthazar grade E, CTSI :10).

Body and tail of the pancreas do not enhance after i.v. contrast (blue arrows).

There is however normal enhancement of the pancreatic head (yellow arrow).

More than 50% of the pancreas is necrotic and there are at least two collections (CTSI : 10)

Necrotizing Pancreatitis

Central gland necrosisCentral gland necrosis is a

subtype of necrotizing pancreatitis.

It represents 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.

serious Dx

Central gland necrosis

Two weeks later the collection in the omental bursa and pancreatic body has increased significantly. The pancreatic tail still enhances and so does the pancreatic head (arrows).

Peripancreatic Collections

resolution

There is a collection in the area of the pancreatic head in the right anterior pararenal space.On a follow up scan the collection is larger.One day later the patient developed septicaemia and percutaneous drainage was performed.After drainage the collection has barely diminished in size and consequently there was suspicion of necrotic tissue. The patient therefore underwent surgery and the collection was found to consist of necrotic debris, The necrotic debris was too thick for successful percutaneous drainage.

Based on imaging alone it is often not possible to determine whether these collections contain fluid or necrotic tissue and whether they are infected or not.Consequently, instead of naming them as 'pseudocysts', 'abscesses' or 'necrosis', it is better to describe them as 'peripancreatic collections'.

Infected necrosis

infected necrosis is:Infection of necrotic pancreatic parenchymaAnd/or necrotic extrapancreatic fatty tissueUsually occurs in the 2nd-3rd week.Most severe local complication of acute pancreatitisMost common cause of death in patients with acute pancreatitisAir bubbles are seen in 20% of cases with infected necrosis.

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Infected necrosis (2)

• here is a normal enhancement of the pancreas with surrounding septated heterogeneous peripancreatic collections with fluid- and fat densities .

• Two weeks later there are air bubbles in the peripancreatic collection, consistent with infected necrosis.

2 weeks later

Pseudocyst• Collection of pancreatic juice

enclosed by a wall of fibrous tissue

• Absence of necrotic tissue is imperative for its diagnosis

• Often communication with the pancreatic duct

• Requires 4 or more weeks to develop

• On CT we cannot diagnose a collection with certainty as a pseudocyst, since it is usually not possible to determine what the content of a collection is

CT of an ICU patient on day 40 with central gland necrosis with a spiking fever. The CT shows a similar collection to that of the previous patient, exept for its pancreatic location.The collection is homogeneous and well-demarcated with a thin wall abutting the stomach.

During endoscopic debridement this collection contained fluid and necrotic tissue which was removed from the area of the pancreas

another example25 d...Homogeneous pancreatic and peripancreatic collection, well-demarcated with an enhancing wall.Since this patient had fever and multiple organ failure, this collection was suspected to be infected necrosis and not a pseudocyst.At surgery the collection contained a lot of necrotic debris, which was not recognizable on CT.

role of MRI

collection

debris

lessons learned

New atlanta definitions

Interstitial edematous pancreatitis

Interstitial edematous pancreatitis

Acute peripancreatic fluid collection

pancreatic pseudocyst

Acute necrotizing

pancreatitis.

Acute necrotizing pancreatitis

acute necrotic collection

walled off cystic necrosis

acute necrotizing pancreatitis

acute necrotic collection

Interstitial edematous pancreatitis

acute peripancreatic fluid collection

d 0 to d 28

acute necrotizing pan.

walled off necrosis

IEPpancreatic pseudocyst

after 28

abscess

wopn

wopn

wopn

pseudocyst

Take home messages• Severity of acute pancreatitis and pancreatic necrosis can only

be reliably assessed by imaging after 72 hours.• Absence of pancreatic parenchymal necrosis does not

preclude a serious course of the illness.• 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.• Name collections always according to 2012 Atlanta definitions.• Central gland necrosis is a subtype of necrotizing pancreatitis

with important implications.