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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5780_Библиотеки_им_академика_М_И_Перельмана.pdf
11.2 Diffuse Changes
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
Possible Errors of Interpretation
..............................................................................................................
n
Ductectasia (Fig. 435a): A greatly enlarged pancreatic duct can mimic a hypoe-
choic pancreas.
n
Fluid-filled duodenum (Fig. 435b): The horizontal part of the duodenum between
the aorta and the superior mesenteric artery may be mistaken for a diffuse hypoechoic change in the pancreas.
ab
Fig. 435a, b Ductectasia mimicking a hypoechoic pancreas. a Massive dilatation
of the pancreatic duct (PD, cursors), which is hypoechoic due to sedimentation.
Arrows: duct stones, some with distal acoustic shadows (S). AO = aorta, VC = vena
cava. b The horizontal limb of the duodenum passes between the aorta (AO) and
superior mesenteric artery (SMA). In the lateral longitudinal scan, the duodenojejunal flexure is lateral to the pancreatic tail and anterior to the inferior mesenteric
vein
n
Differentiating fibrosis from lipomatosis:
x
Fibrosis: coarser echo pattern with induration (digital palpation with indicate
this)
x
Lipomatosis: finer, homogeneous echo pattern with no significant induration
Further Testing
..............................................................................................................
n
In acute pancreatitis:
x
Clinical findings : acute, deep upper abdominal pain
x
Laboratory findings : elevated amylase/lipase
x
CT: routine initial study, may also be used for follow-up (better for differentiating edema, hemorrhage, and necrosis)
x
Early ERCP: in cases with a suspected biliary etiology (sonographic investigation of the gallbladder and the prepapillary bile duct)
n
In chronic pancreatitis:
x
Definition: more than three episodes of acute inflammation
x
Sonographic and clinical findings:
– Ultrasound in early cases may demonstrate no abnormalities or at most may
show irregular borders, duct irregularities, and “en bloc” movement of the
pancreas. Induration (fibrosis) may be noted on digital palpation. Function-
ally, there are still no clinically overt deficits (ERP; see Fig.
– Advanced cases of chronic pancreatitis are usually marked by recurring
bouts of upper abdominal pain (alcohol history?), secondary pancreatogenic
diabetes mellitus, weight loss, and a fatty stool.
436).
11
11
11
Pancreas
Pancreas
Pancreas
299
11.2 Diffuse Changes
y
)
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
11
11
11
Clinical: Fatty stool
Pancreas
Pancreas
Pancreas
Abnormal
Maldigestion Malabsorption
Chronic pancreatitis
(calcification/stones,
ductectasia, cysts)
Pancreatic carcinoma
(circumscribed contour
bulge, truncated duct)
Sequel to necrosis
or surgery
(parenchymal loss)
Abnormal glucose tolerance No elevation Normal
Abnormal
(ERP; ductal dilatation,
string-of-beads sign,
truncated duct,
sts, necrotic cavities
c
Pancreatic ultrasound
Normal
Sprue
Glucose tolerance
Impaired micelle formation
blind pouch syndrome
Fig. 436 Role of sonography in the workup of malassimilation
(cardinal symptoms : weight loss and fatty stool)
Bile loss,
x
24 hour test for stool fat: well above 7 g of fat, stool weight i 150 g
x
Glucose tolerance test to differentiate from malabsorption in sprue :
– Elevated 1 h and 2 h values : favors pancreatogenic fatty stool. (The secretin-
pancreozymin stimulation test is the most sensitive test but is too compli-
cated for routine use; elastase in the stool is too imprecise, with a positive
predictive value of only 50–60 %.)
n
Note: Absence of blood glucose elevation is suggestive of malabsorption.
x
CT: Sensitivity is poor in early forms. In more advanced forms, diagnostic accuracy is 100 % based on the criteria of fibrosis, calcification, ductectasia, and cysts
x
ERCP: duct irregularities.
300
11.3 Circumscribed Changes
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
11.3 Circumscribed Changes
Overview (Table 52):
..............................................................................................................
Table 52.Circumscribed changes in the pancreas
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Anechoic Hypo- or isoechoic Hyperechoic
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Cysts (congenital, pseudocysts, parasitic cysts)
Cystic neoplasia (p. 302) Focal pancreatitis (p. 304) Protein plug or foreign body
Pancreatitis of the head or
tail (see p. 303)
Anechoic Changes
..............................................................................................................
n
Congenital cysts (Fig. 437a):
x
Anechoic
x
Smooth margins
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Pancreas divisum (p. 303)
Pancreatic carcinoma
(p. 304)
Neuroendocrine tumor
(p. 305)
Metastasis, lymphadenopathy (p. 305)
yyyyyyyyyyyyyyyyyyyyyyyyyy yyyyyyyyyyyyyy
Duct stones, calcifications
(p. 305)
(p. 306)
Focal chronic pancreatitis
(p. 306)
Calcified or debris-filled
pseudocyst (p. 307)
Hemangioma (p. 307)
Vascular calcification (p. 307)
11
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Pancreas
Pancreas
Pancreas
ab
Fig. 437a–c Cystic pancreatic masses.
a Congenital cysts (C). SV = splenic vein.
b Incipient pseudocyst (C) following
severe acute pancreatitis. c Two pseudocysts (C) in chronic pancreatitis
(resolved 5 months later).
GB = gallbladder, S = stomach
c
301
11.3 Circumscribed Changes
Schmidt, Ultrasound © 2007 Thieme
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11
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x
Frequently combined with renal and hepatic cysts
x
No evidence of pancreatitis
n
Necrosis, pseudocyst, or parasitic cyst in acute pancreatitis (Fig. 437b):
x
Irregular margins
Pancreas
Pancreas
Pancreas
x
Internal echo pattern is usually complex (necrosis, hemorrhage, infection)
x
Echogenic inflammatory wall (pseudocyst)
x
Aspirate: turbid, greenish, bloody, purulent
n
Cyst in chronic pancreatitis (Fig. 437c):
x
Smooth margins
x
Anechoic
x
Size 2–4 (up to 17) cm
x
Aspirate: sterile, hypocellular, enzyme-rich
n
Parasitic cyst: solitary lesion or rosette-like pattern, echogenic wall
n
Cystic neoplasias (after Klöppel):
x
Ductal adenocarcinoma with cystic features: solid or cystic tumor mass
x
Intraductal papillary mucinous neoplasia: periductal cystic mass in the head of
the pancreas
x
Mucinous cystic neoplasia (cystadenoma, see Fig. 438a): mixed solid-cystic
mass in the body of the pancreas. Occurs predominantly in middle-aged
women
x
Serous cystic neoplasia (microcystic cystadenoma, see Fig. 438b): solid-micro-
cystic mass with prestenotic ductal dilatation. Benign neoplasia that occurs
exclusively in elderly women
x
Solid pseudopapillary neoplasia
x
Unusual cystic neoplasias: cystic mass
ab
Fig. 438a–c Cystic neoplasias. a Mucinous cystic neoplasia (CA, cystadenoma)
in the body and body–tail junctional
area of the pancreas. Ultrasound
demonstrates solid and cystic components (this type of neoplasia should be
excised without prior fine-needle
aspiration because of the potential for
malignancy). b Serous cystic neoplasia
(microcystic cystadenoma) : solid-microcystic mass (C) with associated obstruction of the pancreatic duct (PD). c Ductal
carcinoma with cystic features; solid
c
mass (T) with cystic transformation (C).
AO = aorta
302
11.3 Circumscribed Changes
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
n
Pancreatitis of the head or tail of the pancreas:
x
Mild pancreatitis:
– Hypoechoic tumor-like swelling (tender to pressure)
– Resolves after acute symptoms have subsided
x
Severe pancreatitis (Fig. 439): swelling, plus
– intrapancreatic fluid, necrosis, or hemorrhage
– peripancreatic fluid (directly bordering the pancreas or in the splenic hilum)
!
Caution: Fokal pancreatitis in elderly patients may often caused by a ductal
carcinoma!
Fig. 439 Acute necrotizing pancreatitis: edematous swelling of the pancreas
(P) with peripancreatic fluid (FL).
S = stomach, SV = splenic vein
Hypoechoic and Isoechoic Changes
..............................................................................................................
n
Pancreas divisum (Fig. 440):
x
Isoechoic enlargement of the pancreatic head
x
Visualization of two duct systems (rudimentary pancreatic duct and accessory
pancreatic duct)
Common
bile duct
Accessory
pancreatic duct
11
11
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Pancreas
Pancreas
Pancreas
Minor
duodenal
papilla
Major
duodenal
papilla
a
Incomplete
pancreas
divisum
Complete
pancreas
divisum
Main
pancreatic duct
Fig. 440a, b Pancreas divisum.
a Schematic representation of a com-
plete and incomplete pancreas divisum.
b Pancreas divisum with typical enlargement of the pancreatic head and two
definable ducts (arrows). CO = venous
confluence, VC = vena cava
b
303
11.3 Circumscribed Changes
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
11
11
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n
Focal pancreatitis (Fig. 441): enlarged, circumscribed, hypoechoic to complex
area of pancreatic change
Pancreas
Pancreas
Pancreas
ab
Fig. 441a, b “Groove pancreatitis”: acute focal pancreatitis of the pancreatic
head (uncinate process, arrows) with stenosis of the bile duct. a Upper abdominal
oblique scan. b Upper abdominal longitudinal scan. A = mesenteric artery, Arrow:
duct stone, AO = aorta, CBD = common bile duct, sourrounding hypoechoic
inflammation (cholangitis), VC = vena cava, SV = splenic vein
n
Pancreatic carcinoma (Figs. 442 and 443):
x
Scalloped margins, bulge in pancreatic contour
x
Uniformly isoechoic or hypoechoic lesion with fine peripheral extensions
(spiculations)
x
Prestenotic enlargement of the pancreas
x
Signs of infiltration or displacement (splenic vein, celiac trunk)
x
CDS: no vascularity on unenhanced scans
ab
Fig. 442a, b Pancreatic carcinoma (deemed operable by ultrasound and CT, but
found to be inoperable at surgery). a Hypoechoic tumor (T) in an echogenic lipomatotic pancreas (P). K = veinous confluence b CDS shows no tumor vascularity.
SA = splenic artery, SV = splenic vein
304
11.3 Circumscribed Changes
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
ab
Fig. 443a, b Carcinoma of the pancreatic head (T): hypoechoic mass with fine
extensions. a Compression and obstruction of the bile duct (BD). b Abrupt cutoff
(arrow) of the pancreatic duct (PD) with prestenotic dilatation
n
Neuroendocrine tumor (Fig. 444a):
n
Note: Most insulinomas are detectable only by endosonography, intraoperative
bimanual palpation, or intraoperative ultrasound.
x
Circumscribed round or oval mass with smooth margins
x
No duct obstruction
x
CDS: vascularity
n
Metastasis, lymphadenopathy (Fig. 444b)
x
Metastasis: round hypoechoic mass with smooth margins
x
Lymphadenopathy: bulky round or oval mass
x
Nodal metastasis: hypoechoic or isoechoic
11
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Pancreas
Pancreas
Pancreas
ab
Fig. 444a, b Sharply circumscribed, hypoechoic pancreatic masses. a Metastatic
neuroendocrine tumor of the pancreatic head (T). b Metastatic carcinoma (LN) in
the pancreas (P). AO = aorta, L = liver, SV = splenic vein, VC = vena cava
Hyperechoic Changes
..............................................................................................................
n
Pancreatic duct stones, calcifications (Fig. 445):
x
Solitary or string-of-beads foci of very high echogenicity in the pancreatic duct,
with associated acoustic shadows (and twinkling artifact)
x
Possible ductal dilatation
x
Isolated, intensely echogenic, circumscribed areas with or without definable
acoustic shadows
305
11.3 Circumscribed Changes
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
11
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Pancreas
Pancreas
Pancreas
ab
Fig. 445a, b Pancreatic duct stones and calcifications. a B-mode image: echogenic areas in the pancreas (P) with distal acoustic shadows (S) obscuring the usual
landmarks. b CDS : twinkling and confetti artifacts caused by strong reflectors in the
shadowed region
n
Protein plug, foreign body, air (Figs. 446, 447):
x
Hyperechoic, intensely echogenic structures in the expanded pancreatic duct
x
Air in the pancreatic duct (after papillotomy) appears as mobile, echogenic gas
bubbles
Fig. 446 Protein plug (arrow) in the
dilated, unobstructed pancreatic duct
(PD) in a setting of chronic autoimmune
pancreatitis. SV = splenic vein, AO = aorta
ab
Fig. 447a, b Echogenic structures in the pancreatic duct. a Stent (arrow) inserted
for recurrent bouts of pancreatitis in a pancreas divisum. b Air in the pancreatic
duct (arrow) secondary to a biliary-enteric fistula with a common duct orifice.
AO = aorta, PD = pancreatic duct, SV = splenic vein, P = pancreas
n
Focal chronic pancreatitis (Fig. 448):
x
Circumscribed echogenic or heterogeneous area showing an altered or coarsened
echo pattern
x
306
Possible cysts and calcification
11.3 Circumscribed Changes
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
Fig. 448 Segmental chronic pancreatitis of the pancreatic head (cursors).
P = normal-appearing tail, PD = segmental dilatation of the pancreatic duct
n
Calcified pseudocyst or a pseudocyst filled with pus or debris (Fig. 449):
x
Round, oval or irregular mass with bizarre hypoechoic or hyperechoic components
x
Calcified wall appears echogenic and casts a distal acoustic shadow
n
Hemangioma: round hyperechoic mass
n
Vascular calcification (Fig 450; Fig. 471, p. 319) : straight or curved linear echoes
with acoustic shadows, distributed along the course of the splenic artery
ab
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Pancreas
Pancreas
Pancreas
Fig. 449a–c Causes of heterogeneous
increased echogenicity in the pancreas.
a Peripheral calcification (arrows) of a
pancreatic pseudocyst (C). Cystic structure appears hypoechoic (not anechoic)
due to superimposed partial acoustic
shadowing. S = indented stomach.
b Pseudocyst (C) with a complex echo
pattern, displacing the hepatic artery
(HA). c Large debris-laden pseudocyst
with a combination of anechoic and
echogenic contents
Fig. 450 Calcifications (arrows) with
acoustic shadows (S) in the splenic
artery. P = pancreatic head, AO = aorta,
VC = vena cava, L = liver, C = venous
confluence
c
307
11.3 Circumscribed Changes
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
11
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Possible Errors of Interpretation
..............................................................................................................
n
Mimics of a pseudocyst or necrosis (Fig. 451):
x
Splenic artery that runs a tortuous course through the head and tail of the
Pancreas
Pancreas
Pancreas
pancreas
x
Prepapillary common bile duct
n
Mimics of the splenic vein (Fig. 446, p. 306):
x
Pancreatic duct that is dilated or distorted as a result of scarring
x
Irregular pseudocysts
n
Mimics of pancreatic carcinoma (Figs. 452 and 453; see also Fig. 442, p. 304):
x
Atypical cyst (with intracystic hemorrhage, debris, or calcification; see Fig. 449,
p. 307)
x
Malignant lymphoma or metastasis (Fig. 452b)
x
Cystadenoma, adenoma (see Fig. 438, p. 302)
x
Focal pancreatitis (Fig. 452a)
x
Fluid-filled duodenojejunal flexure (Fig. 453)
ab
Fig. 451a, b Mimics of a pseudocyst or necrosis. a Multiple cross-sections through
the splenic artery (arrows). b Dilatation of the pancreatic duct (PD) and common
bile duct (BD) secondary to a small prepapillary carcinoma of the pancreatic duct.
P = pancreas, L = liver, AO = aorta, VC = vena cava, SV = splenic vein
ab
Fig. 452a, b Mimics of pancreatic carcinoma. a Hypoechoic swelling of the pancreatic head, calcifications (cursors), dilatation and cutoff of the pancreatic duct
(carcinoma in chronic pancreatitis?): acute exacerbation of chronic pancreatitis.
b Hypoechoic tumor (T) in the body and tail of the pancreas: high-grade nonHodgkin lymphoma. AO = aorta, L = liver, P = pancreas, SV = splenic vein
308