3. Phases of acute pancreatitis
Atlanta classification
• Early - first week– only clinical parameter are
needed for management
•
Late - after the first week
clinical and CT findings combined needed
4. Severity based on clinical and
morphological findings
• Mild- No organ failure and no local or
systemic complication
• Moderate - Presence of transient organ failure
less than 48h and/or presence of local
complications.
• Severe - Persistent organ failure > 48 hour.
5. Morphological types
• Acute oedematous or interstitial pancreatitis/
collection/pseudopancreatic cyst
• Acute necrotizing pancreatitis
• Usually the necrosis involves both the
pancreas and the peri pancreatic tissues.
6. How to diagnose acute pancreatitis
• Acute onset of persistent, severe, epigastric
pain often radiating to the back.
• Serum lipase or amylase activity at least three
times greater than the upper limit of normal.
• Characteristic findings of acute pancreatitis on
contrast-enhanced CT (CECT) and less
commonly MRI or US.
7. Clinical out come
• Mild pancreatitis
These patients have no organ failure, no fluid collections and no
necrosis.
These patients usually recover by the end of the first week.
• Moderate severe and severe pancreatitis
Cytokine cascades result in a systemic inflammatory response
syndrome (SIRS), which increases the risk of organ failure.
•
The presence of organ failure is determined by respiratory (pO2↓),
renal (creatinine↑) and cardiovascular failure (blood pressure↓).
•
Many of these patients however will have necrotizing pancreatitis and
the mortality increases when the necrosis becomes infected.
8. Atlanta classification of fluid
collection --4 types
• Contents
– Fluid only in acute peripancreatic fluid collection and
Pseudocyst.
– Mixture of fluid and necrotic material in acute necrotic
collection and walled-off-necrosis
• Degree of capsulation
– Complete encapsulation in pseudocyst and walled off
necrosis
• Time Within 4 weeks
- acute peripancreatic and necrotic fluid collection only
after 4 week for a capsule to form
9. Nature of collection
• All these collections may remain sterile or
become infected.
• Infection is rare during the first week.
10. CT severity index
• The CT severity index (CTSI) combines the
Balthazar grade (0-4 points) with the extent of
pancreatic necrosis (0-6 points) on a 10-point
severity scale.
12. CT for acute pancreatitis
• CT is the imaging modality of choice for the
diagnosis and staging of acute pancreatitis
and its complications.
•
Ultrasound and ERCP with sphincterotomy
and stone extraction play an important role in
biliary pancreatitis.
13. CT imaging
• Since the diagnosis of acute pancreatitis is usually
made on clinical and laboratory findings
• an early CT is only recommended when the diagnosis
is uncertain, or in case of suspected early
complications such as bowel perforation or ischemia
• Sometimes an early CT may be misleading regarding
the morphologic severity of the pancreatitis, because
it may underestimate the presence and amount of
necrosis.
14. Case
• Pic1– normal enhanced
pancrease
Pic2– condition gets
worsen so ct done again
Major part of pancreas
involved
Patient died on 5th day
due to SIRS and multi
organ failure
Meaning CT on 1st day was
under estimate
15. CT criteria
• 1--Acute peri pancreatic fluid collection only
sometimes not or partially encapsulated seen
within 4 wks in interstitial pancreatitis/APF
• 2--Acute Necrotic Collections/ANC contain a
mixture of fluid and necrotic material. They
are not or only partially encapsulated. They
are seen within 4 weeks in necrotizing
pancreatitis
16. CT criteria
• 3– After 4 weeks pseudocyst in interstitial
pancreatitis. This fluid collection is
encapsulated. Pseudo cysts are uncommon in
acute pancreatitis. Most persistent fluid
collections may contain some necrotic
material also.
• 4--After 4 weeks most necrotic collections are
fully encapsulated and are called Walled-off
Necrosis (WON)
17. Interstitial
pancreatitis
• Here an example of
interstitial pancreatitis.
There is normal
enhancement of the
entire pancreatic gland
with only mild
surrounding fatty
infiltration.
• There are no fluid
collections and there is
no necrosis of the
pancreatic parenchyma.
CTSI: 2 points
18. Acute necrotizing
pancreatitis
• The CT shows an acute
necrotizing pancreatitis.
The body and tail of the
pancreas do not
enhance.
There is normal
enhancement of the
pancreatic head (arrow)
• More than 50% of the
pancreas is necrotic and
there are at least two
collections
CTSI: 4 + 6 = 10 points.
19. Necrotizing pancreatitis
• Necrosis of pancreatic parenchyma or
peripancreatic tissues occurs in 10-15 % of
patients.
It is characterized by a protracted clinical
course, a high incidence of local
complications, and a high mortality rateCT..
20. Necrotizing pancreatitis-3 subtypes
1. Commonly--Necrosis of both pancreatic and
peripancreatic tissues (most common).
2. Less commonly--Necrosis of
only extrapancreatic tissue without necrosis
of pancreatic parenchyma
3. Rarely--Necrosis of pancreatic parenchyma
without surrounding necrosis of
peripancreatic tissue
21. Necrotizing pancreatitis on CT
• Necrosis of the pancreatic parenchyma can be
diagnosed on a contrast-enhanced CT ⩾ 72
hours.
•
Necrosis of peripancreatic tissue can be vary
difficult to diagnose, but is suspected when
the collection is inhomogeneous,
i.e. various densities on CT
22. CT versus MRI
• MRI is superior to CT in
differentiating between fluid
and solid necrotic debris.
• Here a patient with several
homogeneous peripancreatic
collections on CT.
• These collections also show
homogeneous high signal
intensity on a fat-suppressed
T2-weighted MRI image, are
fully encapsulated and
contain clear fluid (i.e.
pseudocysts).
23. CT versus MRI
case–2 mths ago pt had necrotizing pancreatitis
• The CT-image shows a
homogeneous peripancreatic
collection in the transverse
mesocolon (arrow).
• A T2-weighted MRI sequence
shows that the collection has a
low signal intensity (arrow).
Most likely this is necrotic fat
tissue (i.e. sterile necrosis or
walled-off necrosis).
This patient had no fever or signs
of sepsis.
• Endoscopic or percutaneous
drainage would have little or no
effect on its size, but increases
the risk of infection
24. Case—acute peri pancreatic collection
• In early phase of ac. Pancreatitis
Intra abdominal fluid collection
and of necrotic tissue with no
wall/ capsule
• (lesser sac ,ant post renal space
of retroperitoneum, transverse
mesocolon and small bowel
mesentry are preferred sites)
• Collection and necrosis is due to
release of activated pancreatic
enzmes They may remain sterile
or develop infection.
• The images show spontaneous
regression of an acute
peripancreatic fluid collection
(APFC).
25. Case– acute necrotic collection
• The findings are:
• Necrosis of the
pancreas
• Inhomogeneous
collection in the
peripancreatic tissue
• No wall
• We can conclude that
this is an acute necrotic
collection - ANC.
26. Case -- collections
Day 5--Normal enhancement of
the entire pancreas.
• Extensive peripancreatic
collections, which have liquid and
non-liquid densities on CT.
• There are at least two collections,
but no pancreatic parenchymal
necrosis (CTSI: 4).
• Day 18- expansion of the
peripancreatic collections and an
incomplete wall is present.
27. Pseudocyst
2mts after acute pancreatitis c/o gastric outlet obstruction with no fever
There is a homogeneous
well-demarcated
peripancreatic
collection in the lesser
sac, which abuts the
stomach and the
pancreas. Clear fluid
with high amylase
The collection
underwent successful
percutaneous drainage,
28. Pseudocyst
• A Pseudocyst is a collection of pancreatic juice or
fluid enclosed by a complete wall of fibrous tissue
It occurs in interstitial pancreatitis and the absence
of necrotic tissue is imperative for its diagnosis.
• Communication with the pancreatic duct may be
present
•
A pseudocyst requires 4 or more weeks to develop
29. D/D pseudocyst
• . True pseudocysts are uncommon, since most
acute peripancreatic fluid collections resolve
within 4 weeks
• The differential diagnosis includes walled-off
necrosis and sometimes a pseudo aneurysm
or even a cystic tumor.
Most often, they occur in the lesser sac.
• Most collections that persist after 4 weeks are
walled-of-necrosis.
30. Walled off necrosis
• Based on CT alone it is sometimes impossible
to determine whether a collection contains
fluid only or a mixture of fluid and necrotic
tissue.
Consequently it is sometimes better to
describe these as 'indeterminate
peripancreatic collections'.
31. Walled off necrotic collection
• On the upper image is a
collection in the area of
the pancreatic head in
the right anterior
pararenal space.
• At this stage, it is not
possible to distinguish
between an acute
peripancreatic fluid
collection and acute
necrotic collection.
32. Won at CT
.
Sometimes at surgery, the collection
contained much necrotic debris, which was
not depicted on CT.
• that at times CT cannot reliably differentiate
between collections that consist of fluid only
and those that contain fluid and solid necrotic
debris with or without infection.
33. Central gland
necrosis
It is specific form of necrotizing
pancreatitis- full thickness
necrosis between the pancreatic
head and tail with disrupted
pancreatic duct
it leads to to persistent collections
as the viable pancreatic tail
continues to secrete pancreatic
juices
• These collections may react
poorly to endoscopic or
percutaneous drainage.
Definitive treatment may require
distal pancreatectomy
38. FNA
• Important remarks concerning Drainage:
• Indications for intervention of evolving peri
pancreatic collections should be based on full
evaluation of clinical, lab, and imaging
• No role for drainage in early collections
• Can be used as a guide for surgical approach
39. Preferred approach for FNA
• The retroperitoneal approach has some
advantages:
• Same compartment as the pancreas.
• No contamination with intestinal flora.
• Gravity.
• Drain runs parallel to pancreatic bed
• Same route for minimal invasive surgery
40. Take home message
• Morphologic severity of acute pancreatitis (including
pancreatic parenchymal necrosis) can only be reliably
assessed by imaging 72 hours after onset of
symptoms.
• CT can not reliably differentiate between collections
that consist of fluid only and those that contain solid
necrotic debris.
In these cases MRI can be of additional value.
• Avoid early drainage of collections and avoid
introducing infection.