Figure 1
Acute edematous pancreatitis. A,B: Contrast-enhanced axial
CT images, venous phase, demonstrating diffuse pancreatic enlargement,
densification of the peripancreatic fat planes (long arrows) and acute fluid
collections in the left anterior pararenal space and in the left paracolic
gutter (short arrows), without areas of parenchymal necrosis.
Figure 2
MRI in acute edematous pancreatitis. A: Axial MRI fast-spin
echo T2-weighted sequence with fat suppression showing diffuse pancreatic
enlargement with increased signal on T2-weighted sequence, loss of the usual
glandular pattern and peripancreatic fluid. B:
Diffusion-weighted echo planar axial MRI sequence showing water molecules
diffusion restriction throughout the entire pancreatic parenchyma.
Pre-contrast (C) and contrast-enhanced (D)
T1-weighted gradient echo axial MRI sequences with fat suppression showing
subtle T1 hyposignal of the pancreatic parenchyma and preserved enhancement,
with no area of necrosis.
Figure 3
Acute necrotizing pancreatitis. A,B: Contrast-enhanced
axial CT images, venous phase. Acute necrotizing pancreatitis in a
52-year-old male patient. Diffuse hypoenhancement of the pancreatic neck,
body and tail (arrows on A), compatible with presence of an
extensive area of necrosis, with a small area of preserved parenchyma in the
uncinate process (arrow on B). C,D: Axial images
and contrast-enhanced CT, venous phase. Acute necrotizing pancreatitis in a
35-year- old woman. Extensive areas of pancreatic parenchymal necrosis (long
arrows) in association with areas of fat necrosis in the left anterior
pararenal space and in the transverse mesocolon (short arrows).
Figure 4
Infected acute necrotizing pancreatitis in a 35-year-old man.
Contrastenhanced axial CT image, venous phase showing liquefied area in the
pancreatic body, compatible with necrosis, with gas inside (arrows) without
an outlined fluidgas level, but intermingled with the fluid, indicating the
presence of thick fluid/pus content. In such a context, gas corresponds to
the presence of infection.
Figure 5
Disconnected duct syndrome. Acute necrotizing pancreatitis with ductal
disconnection in a 61-year-old woman. A,B: Contrast-enhanced
axial CT images, parenchymal arterial phase showing area of necrosis in the
pancreatic body (long arrow on A) affecting a large portion of
the parenchymal thickness, pancreatic tail with preserved appearance (short
arrow on A). On B, one identifies the main
pancreatic duct discharging into the necrotic area (arrow).
Figure 6
Acute fluid collections in a 52-year-old male patient during the second
week of acute necrotizing pancreatitis. A,B,C,D:
Contrast-enhanced axial CT images, venous phase showing hypoenhancement of
the pancreatic body (arrow on A), compatible with presence of
an area of necrosis contiguous with hyperattenuating fluid collection
(probable hematic content) in the epiploic retrocavity (arrow on
B). Other fluid collections are identified between bowel
loops in the peritoneal cavity (long arrows on C, D), in the
left anterior pararenal space (short arrow on D), as well as
reactive parietal thickening of small loops in the left flank (curved arrow
on D) and ascites (black arrow on D).
Figure 7
Acute edematous pancreatitis with pseudocysts. A,B:
Contrast-enhanced axial CT images, venous phase showing some pseudocysts
compressing the pancreatic parenchyma, and others in the epiploic
retrocavity (arrows).
Figure 8
Acute edematous pancreatitis with pseudocysts. A,B:
Contrast-enhanced axial CT images, venous phase showing preserved
enhancement of the pancreatic parenchyma (long arrow on A),
pseudocyst posteriorly to the cephalic segment, uncinate process and in the
mesenterium (short arrows on A,B).
Figure 9
Pseudocyst in acute pancreatitis. A,B: Contrast-enhanced
axial CT image, venous phase showing acute inflammatory changes in the
pancreatic tail (long arrows on A) and pseudocyst with
spontaneously hyperattenuating hematic content (short arrows on
A,B) extending toward the left subphrenic space and
partially restrained by the gastric wall (short arrows on
A,B).
Figure 10
Post-necrotic pancreatic and peripancreatic changes. A,B:
Contrast-enhanced axial CT images, venous phase showing extensive areas of
peripancreatic fat necrosis (arrows). C,D:
Non-contrast-enhanced CT after eight weeks, such areas become more delimited
with a liquefied appearance, characterizing postnecrotic pancreatic and
peripancreatic changes (arrows). D,E: A 37-year-old patient
with acute necrotizing pancreatitis restricted to peripancreatic tissues.
Contrast- enhanced axial CT images, venous phase show preserved pancreatic
parenchymal enhancement (long arrows on D,E), with extensive
areas of peripancreatic fat necrosis (short arrows on D). The
patient presented with a septic condition and was submitted to necrosectomy.
Purulent material was identified in those areas.
Figure 11
Walled-off pancreatic necrosis. A,B: Contrast-enhanced
axial CT images, venous phase. Development of acute necrotizing pancreatitis
in a 45-year-old male patient. A: Extensive necrosis of the
pancreatic body and tail with ill-defined limits and solid appearance
(arrow). B: After two weeks, the delimitation of the necrotic
area with a liquefied appearance can already be observed with necrotic
debris inside (arrow). C,D: Contrast-enhanced axial
(C) and coronal (D) CT images, venous phase. A
42-year-old male patient with circumscribed parenchymal necrosis replacing
the pancreatic body and tail (arrows) after three weeks from the onset of
acute necrotizing pancreatitis.
Figure 12
Walled-off pancreatic necrosis. A,B,C: Contrast-enhanced
axial CT images, venous phase. Extensive necrosis of the pancreatic body and
tail, with peripancreatic inflammatory changes (long arrow on
A). Also, a thrombus is identified within the splenic vein
(short arrow on A). After approximately one month, an area of walled-off
pancreatic necrosis is identified (arrow on B), which should
not be confused with pseudocyst. As the same image is evaluated with a
narrower window, it is possible to identify the presence of necrotic debris
without enhancement within such walled-off pancreatic necrosis (arrows on
C). D,E,F: Axial MRI T2-weighted fast spin echo
images with (D) and without (E) fat suppression,
and non-contrast-enhanced T1-weighted, gradient echo (F)
showing necrotic debris of the pancreatic parenchyma deposited in the
posterior portion of the collection (arrows on E,F), with
signal hyperintensity on T1-weighted sequences, indicating the presence of
hemorrhagic component (arrows on E).