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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_585_Библиотеки_им_академика_М_И_Перельмана.pdf
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3 Imaging ofCommon Biliary Tract Diseases
73
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Fig. 3.50 Intrahepatic cholangiocarcinoma. (a) On plain CT scan,
patchy low-density shadow is seen in the right lobe of the liver, with
uneven internal density, unclear boundary, and inwardly sunken local
liver capsule. (b) Only slight enhancement is seen in the arterial phase
of enhanced scan; (c) The enhancement in portal phase is higher than
that in arterial phase, the internal structure and boundary of the lesion
are relatively clear, and the perfusion of peripheral liver parenchyma is
increased. (d) The enhancement of lesions in the delayed phase is further increased
It is generally believed that the portal vein is less involved
in ICC.Studies have shown that ICC invades portal vessels,
nerves, and lymphatic vessels. When the portal vein is
invaded, the periportal sheath is thickened and the lumen is
narrowed. However, tumor thrombus is uncommon, and
occasionally a sectionally or foliate hypoperfusion area is
visible.
3.4.7.2 MRI Findings (Figs.3.51 and3.52).
Plain Scan It showed hypointense on T1WI and iso- and
hyperintense on T2WI.Signal strength correlated with the
composition of intra-tumoral components such as brous tissue, mucus, and necrotic tissue. With the presence of many
brous tissues, the lesions on the T2WI presented iso- or
hypointense, otherwise, they would present hyperintense.
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Fig. 3.51 MRI ndings of intrahepatic cholangiocarcinoma. (a, b)
T1WI and T2WI show long T1 and T2 signals with clear boundary in
the left lobe of the liver. (c) The enhancement of lesions in arterial phase
is not obvious by contrast-enhanced scan; (d) The edge of the lesion at
the portal vein stage shows garland-like enhancement; (e) The scope of
enhancement in the delayed phase is further increased; (f) Hepatobiliary
specic lesions shows low signal and slightly high signal in the center
of lesions
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Fig. 3.52 MRI ndings of intrahepatic cholangiocarcinoma. (a)
Abnormal signal shadow of T1 with slightly longer blade shape on the
right liver, with unclear boundary and local depression of liver capsule;
(b) Abnormal signal shadow of T2 with slightly longer blade shape on
the right liver, and the intrahepatic bile duct is signicantly dilated; (c)
Multiple dilated bile ducts can be seen in the lesion in the coronal posi-
However, the hypointense on T2WI did not only indicate the
composition of brous tissue, but also coagulative necrosis.
There was no capsule shadow around the lesion. Fiber traction can cause local depression of the liver capsule around
tion of T2WI. (d) The hepatobiliary phase of Gd-EOB-DTPA-enhanced
MRI scans in the coronal plane shows that the overall focus of the
lesion does not take up liver-specic contrast agents, mild enhancement
is observed in some parts, and multiple metastases can be seen in the
liver, showing a clearer image than T2WI, which is helpful to determine
the nature of the lesion
specic contrast agent was applied, most of the lesions were
not inltrated, and band-like and small patchy lesions with
slightly hyperintense (representing delayed enhancement,
not inltration) could be observed (Cheng etal. 2020).
the lesion.
MRCP This can display the whole picture of intrahepatic
Enhanced Scan Typical manifestations were similar to
those of CT.When ICC contained a large number of tumor
cells and only a few ber components, the whole tumor was
signicantly enhanced in the arterial phase, but the enhancement still continued until the portal phase and the delayed
phase. It is worth mentioning that when the hepatocyte-
bile duct tree, the location and extent of tumor obstruction. It
can show intra-tumoral bile duct dilatation and proximal bile
duct stenosis, as well as the invasion and compression of
extrahepatic bile duct by hilar lymph node metastasis.
However, the denition of MRCP is usually inferior to that
of direct cholangiocarcinoma.
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3.4.7.3 Special Manifestations
• Mucinous cholangiocarcinoma produces abundant vis-
cous mucin, and the dilated bile duct can also be seen in
the lesion. In MRI plain scan, the lesion presents obvious
hyperintense on T2WI.Very few ICCs destroyed the bile
duct, forming an intratumor bile lake.
• ICC can be associated with intrahepatic infection, espe-
cially when it is complicated with liver abscess. The clini-
cal and imaging manifestations of liver abscess may cover
up the signs of ICC, resulting in misinterpretation leading
to misdiagnosis. When the inner edge of the abscess wall
is not smooth and there is a small wall nodule or when the
peripheral edema zone with low-density does not match
with the routine changes of the liver abscess, the clinician
should be alert to possibility of liver abscess combined
with ICC.
• ICC has varied enhancement patterns in contrast-
enhanced CT scans: Non-enhanced: The lesion usually
has a relatively clear boundary and is surrounded by an
abnormal perfusion area. The adjacent bile duct is dilated,
and the lesion may have no obvious enhancement because
of the vast necrotic area inside, resulting in partial
coagulation. Ring-shaped enhancement: It is particularly
important to distinguish it from the pseudocapsule when
the enhanced foci around the lesion resemble a thin ring-
shaped pattern. The range of peripherally ring-shaped
enhancement of ICC is usually increased in the portal and
delayed phases compared with the arterial phase; how-
ever, the pseudocapsule of HCC usually has a relatively
sharp boundary, presenting a continuous narrow
hypodense or delayed enhanced lesion; Enhancement in
the arterial phase and reduced enhancement in the portal
phase: Such ICC tissues have less necrosis and less
brous components. The tumor cells are relatively abun-
dant, and there is no pseudocapsule on the periphery of
the tumor (Fig.3.53).
3.4.8 Periampullary Carcinoma
The ampulla is located in the medial aspect of the descending portion of the duodenum and is the bulging part of the
duodenal papilla. Circularly arranged smooth muscle around
the ampulla of Vater forms the sphincter of Oddi. The
ampulla region includes the ampulla of Vater, sphincter of
Oddi, distal common bile duct, duodenal papilla, and head of
the pancreas. Because of their close proximity to each other,
the clinical manifestations of a heterogeneous group of neoplasms arising from these areas are characterized by progressive obstructive jaundice, and the treatment options for them
are similar. Therefore, they are collectively referred to as
periampullary carcinoma.
The clinical symptoms of periampullary carcinoma
include various manifestations induced by obstructive
jaundice, such as yellow staining of the skin and sclera, itching of the skin, clay-colored stools, dark urine, and loss of
appetite. Severe periampullary carcinoma can progress to
weight loss and anemia. Periampullary carcinoma can be
caused by cancer necrosis and hemorrhage, and patients may
test positive for fecal occult blood.
3.4.8.1 Radiographic Findings
Periampullary carcinoma mainly manifests at imaging as
nodules in the ampulla, extensive dilation of the proximal
bile duct, and dilatation of main pancreatic duct. The specic
manifestations are as follows:
3.4.8.2 CT Findings
CT showed stenosis and truncation of the lower segment of
the common bile duct and thickening of the bile duct wall.
An enhancing mass could be observed on contrast-enhanced
scan. Adenocarcinoma of the descending duodenum was
demonstrated with thickening and stiffness of the duodenal
wall. Papillary carcinoma was characterized by bulging of
duodenal papillae and tumor masses projecting into the
intestinal cavity (Chong etal. 2012).
3.4.8.3 MRI Findings
On T1WI, the distal end of the common bile duct shows isoor hypointense nodules, while on T2WI, iso- or slightly
hyperintense nodules are predominant. Delayed enhancement is common in contrast-enhanced scans. MRCP shows a
smooth stricture in the distal CBD with gradual tapering or
more abrupt narrowing, often associated with dilatation of
the pancreatic duct, resulting in the “double-duct sign.” The
“double duct sign” is suggestive of the tumor location. The
source images show lling defects at the distal CBD end
(Fig.3.54).
3.4.9 Combined Hepatocellular-Cholangiocarcinoma
Combined Hepatocellular-Cholangiocarcinoma (cHCC-CC)
is a rare variant of Primary Liver Cancer (PLC), with a variably reported incidence between 0.4% and 14.2% in different regions (Jarnagin etal. 2002; Yano etal. 2003; Liu etal.
2003; Ng etal. 1998; Kim etal. 2014). A denite histopatho-
logical diagnosis of cHCC-CC requires the presence of
unequivocally mixed components of both hepatocellular carcinoma and cholangiocarcinoma, in the tumor. The pathogenesis of this rare cancer remains unclear, its preoperative
diagnosis is difcult, and its prognosis is dismal. The clinical
presentations of cHCC-CC are non-specic, and a wide
array of symptoms include epigastric pain or discomfort. It
has clinical features in common with hepatocellular carcinoma and cholangiocarcinoma, which involve strong male
predominance. A number of studies conducted in China have
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3 Imaging ofCommon Biliary Tract Diseases
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Fig. 3.53 MRI ndings of cholangiocarcinoma of the left lobe of the
liver. (a, b) Round long T1 abnormal signal shadow in the left hepatic
lobe; no signicant changes in T1WI OP and IP signals; (c) The lesions
on T2WI show high signal and dilated small bile duct shadow can be
seen in the lesions. (d) MRCP shows partial intrahepatic bile duct trun-
f
cation and slight dilation of distal intrahepatic bile duct. (e)
Heterogeneous enhancement of lesions during arterial phase in the
enhanced scan; (f) The enhancement in the portal phase is weaker than
that of the arterial phase
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Fig. 3.54 CT and MRI ndings of ampullary carcinoma. (a) In CT
enhanced scanning of arterial MPR, soft tissue density nodules are
observed in the ampulla, lesion enhancement is less uniform, and the
upper bile duct is signicantly dilated. (b) The portal phase shows further enhancement of the lesion, and multiple metastases can be detected
by scanning the liver and adjacent abdominal cavity; (c) On T1WI
image, the lesion presents a low signal nodular shadow. (d) The coro-
nary lesion in T2WI shows slightly low-signal nodular shadow. The
lower segment of the common bile duct tapers, and the main pancreatic
duct is also signicantly dilated. (e) MRCP shows “soft rattan” dilatation of the common bile duct and intrahepatic bile duct, as well as signicant dilatation of the pancreatic duct. (f) Contrast-enhanced scan
shows heterogeneous enhancement of lesions, thickening, and enhancement of adjacent bile duct wall
3 Imaging ofCommon Biliary Tract Diseases
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demonstrated a similar patient prole including associated
underlying cirrhosis and hepatitis B, as well as elevated
serum levels of CA19-9 and AFP.
3.4.9.1 Imaging Findings
The imaging features of cHCC-CC are non-specic and governed by the proportion of hepatocellular carcinoma vs.
cholangiocarcinoma. Each of the two components has its
own characteristic imaging features. HCC presents a wash-in
and wash-out contrast enhancement pattern and cholangiocarcinoma show a continuous enhancement. Pattern. MRI
reaches a signicantly higher sensitivity and accuracy than
CT in the detection of cHCC-CC.
3.4.9.2 MRI Findings
The cHCC-CC shows hypointense on T1WI.On T2WI, they
appear relative hyperintense and the lesions are visualized as
a b
a heterogeneous mass, showing a mosaic pattern and hyperintensity on diffusion-weighted images (DWI). Hepatocytespecic contrast agents (gadoxetate disodium) are injected
into the tumor for enhanced scanning. The arterial phase is
markedly enhanced, and the clearance of portal phase and
delayed phase is low, showing a slow wash-in and wash-out
pattern. The enhancement of pseudo-capsule is also observed.
The central part of the hepatobiliary special phase shows an
obvious high signal and peripheral low signal (target sign).
In the hepatobiliary phase, the two components can express
their histological characteristics more signicantly. The
higher the proportion of the CC component in cHCC-CC, the
more abundant brous stroma and more obvious the target
sign in the hepatobiliary phase. Target sign has high signicance for the preoperative diagnosis of cHCC-CC (Figs.3.55
and 3.56).
c
Fig. 3.55 MRI ndings of cHCC-CC. (a) Patchy short T2 signal is
observed in the lesion at the right posterior lobe of the liver. (b) Delayed
enhancement in hepatobiliary specic phase; (c) (color) The tumor tis-
sue consists of a nested hepatocellular carcinoma (white arrow) and an
adenotubular cholangiocellular carcinoma (black arrow)
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Fig. 3.56 cHCC-CC in the right posterior lobe. (a) Contrast-enhanced
scan shows that early arterial enhancement is not evident in the lesion
at the upper right posterior lobe; (b) Signicant peripheral enhancement in late arterial phase; (c) Central delayed enhancement at portal
venous and equilibrium phases, and peripheral enhancement clearance;
(d) Equilibrium period with false envelop sign (White arrow); (e) The
central enhancement of hepatobiliary specic period is more obvious
than before, and the peripheral portion without Gd-EOB-DTPA intake
shows lower signal, forming the target sign
3 Imaging ofCommon Biliary Tract Diseases
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3.5 CT andMRI Diagnosis ofObstructive
Jaundice
Obstructive jaundice is caused by mechanical obstruction of
bile capillaries, the canaliculi, the left and right hepatic ducts,
common hepatic duct, or the common bile duct. It can be
divided into intrahepatic and extrahepatic obstructive jaundice according to the location. The extrahepatic obstructive
jaundice generally requires surgical intervention, and most
intrahepatic obstructive jaundice is treated with medical
therapy. Therefore, differentiating the location and underlying cause of obstructive jaundice is of high signicance for
clinical treatment (Singh etal. 2014). The diagnostic procedures of CT and MRI for obstructive jaundice and issues to
be solved include:
• Diagnosis of extrahepatic obstructive jaundice.
• Denition of the obstruction plane.
• Identication of benign and malignant obstruction.
• Histological diagnosis of etiology.
3.5.1 CT andMRI Signs ofExtrahepatic
Biliary Obstruction
3.5.1.1 Intrahepatic Biliary Dilatation
CT Findings
Normally, intrahepatic bile ducts above the third branches
cannot be displayed on either conventional or high- resolution
CT scans. Visualization of smaller bile ducts within the liver
always indicates dilatation of the intrahepatic bile duct.
When obstructive jaundice occurs, the intrahepatic bile ducts
are generally dilated and taper at the hilum, showing water
dense tubular branching structures with clear boundaries.
Contrast-enhanced scan is important for showing intrahepatic bile duct dilatation. The dilated bile duct runs parallel
to the adjacent enhanced portal vein (Fig.3.57).
MRI Findings
The SE sequence of conventional MRI shows hypointense
on T1WI hepatic duct and hypertense on T2WI.Normally,
T2WI shows left and right hepatic ducts and their 1–2
branches; T1WI is inferior to T2WI in displaying normal
hepatic ducts, but enhanced T1WI is helpful in showing
dilated intrahepatic bile ducts. The intrahepatic bile ducts
typically run parallel to the adjacent portal vein, and its normal diameters range from 2mm to 3mm or 1/3 of the diameter of the accompanying portal vein. Most of the bile ducts
in the periphery of the liver cannot be displayed. It is generally believed that when the diameter of the left and right
hepatic ducts is greater than or equal to 5mm or their diam-
eters are similar to that of the accompanying portal vein,
abnormal dilatation of the intrahepatic bile duct can be
diagnosed. MRCP shows that the normal intrahepatic bile
duct exhibits a dendritic distribution and the tributaries form
the right and left hepatic ducts. The fusion of the right and
left hepatic ducts forms the common hepatic duct. When the
intrahepatic bile duct is dilated, MRCP shows the dilated bile
duct with hyperintense extending from the liver hilum to the
liver periphery, in multiple directions (Figs.3.58 and 3.59).
3.5.1.2 Extrahepatic Bile Duct Dilatation
The common hepatic duct and the common bile duct are collectively called extrahepatic bile ducts. The normal extrahepatic bile duct has a slender spindle shape on the coronal
image, which means the diameter of the middle portion of
the extrahepatic bile duct is slightly larger than that of the
upper and lower portions. Extrahepatic bile duct dilatation
can be conrmed when the diameter of the normal extrahepatic bile duct is less than 6mm, or the diameter of extrahepatic bile duct is equal to or larger than the diameter of portal
vein parallel with it. If the diameter of extrahepatic bile duct
is 7–9 mm, the obstruction should be judged comprehensively according to clinical manifestations. For example, for
patients undergoing cholecystectomy for cholelithiasis, the
bile duct can maintain a certain degree of dilation, generally
less than 10mm, but the clinical biochemical examination
has no signs of obstructive jaundice; dilatation of extrahepatic bile duct was considered only when the diameter was
larger than 9mm in patients without cholecystectomy and
above 60years old; while for patients without cholecystectomy and below 60years old, the clinician must be alert for
biliary obstruction when the diameter of extrahepatic bile
duct is more than 7mm.
Extrahepatic bile duct dilatation appears as a circular
water-like hypodensity ring on CT, and the disappearance of
the annular shadow is toward the end of the dilated bile duct,
indicating the location of biliary obstruction (Fig.3.60).
Extrahepatic bile duct dilatation shows a circular waterlike long T1 and long T2 on the axis of MRI, and the diameter of the tube is increased (Fig.3.61).
3.5.2 Signs ofCT andMRI forDetermining
theObstruction Plane
Extrahepatic bile duct obstruction is horizontally divided
into four segments: hilar segment (left and right hepatic
ducts and common hepatic duct), superior segment of the
pancreas, the pancreatic head, and the ampulla segment. The
location of obstruction can be determined by observing the
anatomical structure around the end of the dilated extrahepatic bile duct.
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Fig. 3.57 CT ndings of normal intrahepatic bile duct and extrahepatic obstructive jaundice. (a) Non-contrast CT scan shows normal
manifestations of intrahepatic bile duct, but does not show intrahepatic
bile duct; (b) CT enhanced scan shows normal manifestations of intra-
hepatic bile duct, but normal did not show intrahepatic bile duct; (c, d)
Plain CT scan shows intrahepatic bile duct dilatation; (e ~ f) CT
enhanced scan shows intrahepatic bile duct dilatation