Diagnostic Ultrasound - Abdomen and Pelvis

Acute Pancreatitis
Diagnoses: Pancreas
TERMINOLOGY
• Acute inflammatory process of pancreas with variable
involvement of other local tissues and remote organ
systems
• Types
○ Interstitial edematous pancreatitis (IEP), necrotizing
pancreatitis (NP)
○ Acute pancreatic fluid collection (APFC), ±infection
○ Acute necrotic collection (ANC), ± infection
IMAGING
• Focal or diffuse enlargement of pancreas with ill-defined
margins, infiltration of peripancreatic fat
• Blurred pancreatic outline/margin: Due to pancreatic
edema and peripancreatic exudate
• Heterogeneous echotexture in patients with
intrapancreatic necrosis or hemorrhage
• Collections: Anechoic peripancreatic fluid = APFC; fluid
within pancreatic parenchyma or containing debris = ANC
KEY FACTS
• US best to evaluate for cholelithiasis in acute pancreatitis of
unknown etiology
○ In mild pancreatitis, sonographic signs may be subtle or
normal
• CECT best in late phase to delineate extent of inflammation
and detect necrosis and complications
• MR best to detect choledocholithiasis (MRCP) or in patients
who cannot undergo CECT
TOP DIFFERENTIAL DIAGNOSES
• Infiltrating pancreatic carcinoma
• Lymphoma & metastases
• Autoimmune pancreatitis
• Perforated duodenal ulcer
• "Shock" pancreas
CLINICAL ISSUES
• Revised Atlanta Classification of Acute Pancreatitis: Early
phase < 1 week, late phase > 1 week
(Left) Transverse ultrasound
shows a markedly
heterogeneous, enlarged
pancreas ſt consistent with
acute interstitial edematous
pancreatitis (IEP). There is a
small amount of free fluid
surrounding segment III of the
liver anteriorly. (Right)
Transverse ultrasound shows a
markedly hypoechoic
pancreatic body ſt suggestive
of focal necrosis, relative to
the normal echogenicity in the
head . This was confirmed
with CECT.
(Left) Transverse ultrasound
shows an enlarged pancreas
ſt consistent with IEP, with
an anterior fluid collection
consistent with APFC. (Right)
Transverse CECT
demonstrates heterogeneous
decreased enhancement of the
pancreatic body relative to
the head ſt, consistent with
acute IEP. There is an APFC
adjacent to the tail. The
common bile duct is dilated
secondary to a distal
obstructing calculus (not
visible on CT), with associated
minimal pancreatic ductal
dilatation st.
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