Circumscribed Changes

Table 44 ■ Circumscribed hepatic changes

Anechoic

Hypoechoic

Isoechoic

Echogenic, hyperechoic

Hepatic cysts (p. 242)

Portal vein ectasia (p. 243)

Aneurysms, shunts (p. 243)

Cystic lesions (p. 244)

Focal sparing in fatty infiltration (p. 245)

Hypoechoic transformation of the caudate lobe (p. 246)

Regenerative nodule in hepatic cirrhosis (p. 246)

Hemorrhagic hepatic cyst (p. 247)

Portal vein thrombosis (p. 247)

Focal nodular hyperplasia (p. 248)

Atypical hemangioma (p. 49)

Primary hepatic carcinoma (p. 49)

Metastases (p. 250) Systemic hematologic diseases (p. 250)

Atypical lobulation (p. 251)

Isoechoic metastases (p. 251) Focal nodular hyperplasia (p. 248)

Diaphragmatic crura (p. 251)

Focal fatty infiltration (p. 252)

Echogenic ligamentum teres (p. 252)

Echogenic portal tracts ("starry sky") (p. 253)

Fresh hematoma (p. 253)

Hemangioma (p. 253) Lesions in porphyria (p. 254)

Primary hepatic carcinoma (p. 254)

Metastasis (colon carcinoma, carcinoid, p. 254)

Calcification (p. 254)

Intraductal stones (p. 254) Pneumobilia (p. 254)

Hemorrhagic cyst (p. 254)

"J n Liver cysts (Figs. 334-336): congenital or acquired. May be solitary or multiple and may occur in a cystic liver, as biliary cysts, or in Caroli syndrome

• Solitary and multiple cysts:

- Anechoic round lesions (or elliptical when flattened by other organ structures; show tapered extensions when close to portal tracts); smooth margins

- Distal acoustic enhancement

- Weakly echogenic wall (with edge shadowing)

- Occasional septations

- High-resolution scan may provide an edge-on view of the cyst wall

- Associated mass effects (on vessels, vena cava, or portal vein)

• Cystic liver: greatly enlarged liver of variable size (> 17-20cm). In 50% of patients other organ systems are involved (polycystic kidneys, pancreatic cysts)

• Biliary cysts: Ultrasound can define the affected bile duct, which occasionally contains a stone.

• Caroli syndrome (congenital dilatation of the intrahepatic bile ducts, Fig. 336): segmental, saccular dilatation of the bile ducts

Peliosis Hepatis UltrasoundPeliosis Hepatis UltrasoundPeliosis Hepatis Ultrasound

Fig. 334a-d Cystic masses in the liver. a-c Simple cysts (C). a Typical cystic criteria with wall echoes (arrows). b Septated cysts. c CDS: no internal vascularity. d Multiple anechoic round masses with acoustic enhancement posterior to the cysts

Gallbladder Cancer Ultrasound

Fig. 335a-c Cystic lesions: a, b Stone in a biliary cyst communicating with the right hepatic duct (confirmed at operation): incomplete acoustic shadow. The patient presented clinically with biliary colic (but no stones in the gallbladder). c Peliosis hepatis. The appearance is similar to that of hepatic cysts (left), but the liver presents an irregular, patchy hypoechoic structure with multiple echo-free cystic masses up to 10 mm in size (arrows). When the image is magnified, the relationship of the cysts to portal vessels can be appreciated. IVC = inferior vena cava

Multiple Hepatic Cysts

Fig. 335a-c Cystic lesions: a, b Stone in a biliary cyst communicating with the right hepatic duct (confirmed at operation): incomplete acoustic shadow. The patient presented clinically with biliary colic (but no stones in the gallbladder). c Peliosis hepatis. The appearance is similar to that of hepatic cysts (left), but the liver presents an irregular, patchy hypoechoic structure with multiple echo-free cystic masses up to 10 mm in size (arrows). When the image is magnified, the relationship of the cysts to portal vessels can be appreciated. IVC = inferior vena cava

Bilious Residual Color

Fig. 336a, b Cystic dilatation of intrahepatic bile ducts (C) in Caroli syndrome. a Stones and incomplete shadowing (arrow) with intra- and extrahepatic duct stones. b Residual intrahepatic stones (arrow) following operative treatment; cystic duct expansion has resolved n Portal vein ectasia (peliosis hepatis; rare; Fig. 335):

• Multiple round or oval, tapered, or angular anechoic lesions that communicate with portal venous branches

• No detectable Doppler flow n Hepatic artery aneurysm, arteriovenous shunts, Osler disease:

• Round, anechoic, pulsating lesion

• Communicates with the artery (Doppler signal, color flow detection by CDS)

jg n Cystic lesions (Figs. 337-339): inflammatory, infectious (echinococciasis, ,-ï abscess), traumatic (hematoma), or neoplastic (cyst-like metastasis, regressive liquefied metastasis)

• Echinococcal cyst (E. granulosis, Fig. 337): anechoic round lesion (see also cystic liver, p. 153) echogenic wall, and calcifications in cystic echinococcosis

M Note: Alveolar echinococciasis (E. multilocularis = fox tapeworm) presents as a solid, infiltrating tumor-like mass.

• Hematoma, abscess (Fig. 338): usually has irregular margins without a cyst wall. May contain low-level internal echoes

Cystic Lesion Gallbladder BedHepatic Fat Infiltration Chart

h n Focal sparing of the liver in fatty infiltration (Figs. 340 and 342):

• Most commonly found in the periportal region and adjacent to the gallbladder bed of the liver

• Elliptical to triangular shape

• May occasionally show a patchy or flame-shaped distribution throughout the liver n Focal sparing of the liver in fatty infiltration (Figs. 340 and 342):

• Most commonly found in the periportal region and adjacent to the gallbladder bed of the liver

• Elliptical to triangular shape

• May occasionally show a patchy or flame-shaped distribution throughout the liver

Fig. 339a, b Carcinoid metastases (neuroendocrine tumor). a Typical, predominantly liquefied mass lined by peripheral, echogenic tumor tissue. b CDS demonstrates a hypervascular mass (unlike other metastases)

Fig. 340 Focal sparing in fatty infiltra- Fig. 341 Hypoechoic quadrate lobe tion; Polygon-shaped hypoechoic area (segment IV, arrows) adjacent to the

(arrow) adjacent to the gallbladder bed gallbladder (GB) in an otherwise fatty of the liver liver 245

Focal Fatty Infiltration The Liver
Fig. 342a, b Regional differences in fatty infiltration with focal sparing (arrows) in segment VIII between the right and left hepatic veins (HV), which pass unchanged through the spared area. No additional tests were required. a B-mode image, b CDS

n Decreased echogenicity of the caudate lobe (Fig. 343):

• Relatively coarse, hypoechoic texture

• Enlarged liver with bulging contours in hepatic cirrhosis

71

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11; .

Jt&F*

CL

: .

- ,

äM-ä-''-

VC .¡:'

Fig. 343 Decreased echogenicity of the caudate lobe (CL, segment I) anterior to the vena cava (VC) in an otherwise normal-looking liver

□ Regenerative nodule in a cirrhotic liver (Fig. 344):

□ Note: Differentiation is mainly required from primary hepatocellular carcinoma

• Pea- to cherry-sized nodule

• Intrahepatic regenerative nodule: round, hypoechoic

• Peripheral regenerative nodule: rounded bulge in the liver contour

n Hemorrhagic liver cyst (Fig. 345):

• Hypoechoic mass with smooth margins

• Internal echoes are often seen with position changes

Fig. 345 Hemorrhagic liver cyst: hypoechoic, sharply circumscribed mass with a faintly echogenic wall n Intrahepatic portal vein thrombosis (Fig. 346):

• Round, elliptical or elongated, depending on the plane of section

• Loose echo texture, isoechoic to slightly hypoechoic

Fig. 346 Intrahepatic portal vein thrombosis (VT): enlarged vessel lumen with intraluminal echoes. All of the small branches (hypoechoic foci) are throm-bosed together with the main trunk and tributaries. Clinical presentation: portal vein thrombosis with a fatal outcome. C = liver cyst n Abscess (Fig. 347):

• Hypoechoic (anechoic) to hyperechoic, heterogeneous echo pattern

• Irregular margins, frequently ill-defined

• Often contains fine, echogenic gas bubbles with incomplete acoustic shadows or reverberations

• Hyperechoic pyogenic membrane is often present

Isoechoic TexturePyogenic Membrain

Fig. 347a, b Liver abscess. a Liver abscesses resulting from septic cholangitis: lesions with ill-defined margins (arrows). b Liver abscess resulting from the biliary spread of infection: nonhomogeneous mass with ill-defined margins, a faintly hypoechoic rim, and central liquefaction (CL). The lesion is avascular on CDS 247

Fig. 347a, b Liver abscess. a Liver abscesses resulting from septic cholangitis: lesions with ill-defined margins (arrows). b Liver abscess resulting from the biliary spread of infection: nonhomogeneous mass with ill-defined margins, a faintly hypoechoic rim, and central liquefaction (CL). The lesion is avascular on CDS 247

¡j n Focal nodular hyperplasia (FNH, Fig. 348):

,-i • Hypoechoic round or elliptical mass, usually with smooth margins

• Echo pattern is often heterogeneous due to the presence of (central) connective tissue (= scars)

• Echogenic extensions radiating toward the periphery (stellate scar)

• CDS: vessels passing through the radial connective tissue ("spoked-wheel" pattern)

Sonographic Fatty Liver

n Adenoma (Fig. 349; see p. 450): resembles in B-mode FNH, as it consists entirely of hepatocytes and blood vessels:

• Uniformly isoechoic or hypoechoic mass

• Smooth margins

Focal Nodular Hiperplasia Atipical
Fig. 349a, b Liver adenoma. a Isoechoic tumor with focal anechoic necrosis/ hemorrhage. b Power Doppler: distinctive vascularization with arterial supply. 248 Histology: hepatocellular adenoma

• Pseudocapsule or hypoechoic rim jj

• Possible low-level internal echoes due to intralesional hemorrhage

• CDS: well-vascularized tumor without a characteristic vascular pattern. Arterial feeding vessels can be demonstrated.

n Atypical hemangioma (Fig. 350):

• Cloudy hypoechoic texture (especially in a fatty liver)

• Large tumors present a complex, patchy hypoechoic to hyperechoic pattern due to regressive changes (calcifications, intralesional hemorrhage).

• A peripheral halo or vascular pedicle may be present.

Fig. 350 Atypical hypoechoic hemangioma (H) penetrated by an arterial vessel (red). Other sonographic features are indistinguishable from those of other tumors

n Primary hepatic carcinoma:

• Hepatocellular carcinoma (Fig. 351 ):

- Variable appearance; typical metastatic appearance when found in an intact liver

- Hypoechoic, isoechoic, hyperechoic, or nonhomogeneous. Solitary or isolated lesions in a cirrhotic liver often do not have a peripheral halo.

- Frequent regressive changes (intralesional hemorrhage, calcification)

- CDS: marked vascularization by arterial tumor vessels with no typical pattern of arrangement ("chaotic")

Fig. 351 Primary hepatocellular carcinoma: several slightly hypoechoic tumor masses (T) in a liver affected by alcoholic toxic cirrhosis; ascites

• Cholangiocellular carcinoma (Fig. 352):

- Diffuse type of growth

- Isoechoic or sometimes hypoechoic texture (due to heavy fibrosis)

- Infiltration

- Locoregional metastases, ascites

Cholangiocellular Carcinoma

Fig. 352 Primary cholangiocellular carcinoma (CCC) of the liver: lesion with ill-defined margins. Changes identical to CCC have been observed in thorotras-tosis (NB: these cannot be positively distinguished from focal sparing by fatty infiltration)

n Metastases (Fig. 353; Fig. 195, p. 150; Figs. 665-668, p. 443, 444):

• Cyst-like metastases often have irregular margins

• Small, intensely hypoechoic metastases, with or without a hypoechoic rim, represent young lesions. Multiple lesions with the same appearance indicate synchronous metastasis. Lesions ofvarying size and appearance represent multiple tumor generations.

• CDS: no detectable intratumoral or peripheral vessels (except in metastases from neuroendocrine tumors, hepatocellular carcinoma, or renal cell carcinoma)

Fig. 353a, b Hepatic metastases. a Multiple intensely hypoechoic metastases (M) of the same shape and size (synchronous lesions) with peripheral halos. b Metastases of varying size and echogenicity, partially confluent (multiple tumor generations)

n Hematologic malignant systemic diseases (Figs. 354, 333, p. 240):

• Micronodular lesions (in chronic myeloid leukemia) or macronodular lesions (with high-grade lymphomas, lymphogranulomatosis)

• Intensely hypoechoic, usually without a peripheral halo

Micronodular Contour

Fig. 354 Chronic myeloid leukemia: pronounced hypoechoic nodular infiltrates (arrows) in the liver (L). LN = enlarged, infiltrated lymph node

• Often accompanied by other intra-abdominal sites of lymph node infiltration;

similar appearance with splenic involvement

n Atypical lobulation (Fig. 355):

• Rounded, sharply circumscribed bulge in the liver contour

• Internal echo pattern identical to that of the liver parenchyma

• Bulging contours

• With a Riedel lobe: may project past the kidney or gallbladder

Fig. 355 Atypical lobulation: Riedel lobe (RL). GB = gallbladder

Crus The Diaphragm Sonographically

n Isoechoic metastases (Fig. 356): can be identified only by the presence of a hypoechoic rim, displacement, or infiltration. Better delineation is obtained with THI, CDS, or contrast-enhanced sonography.

• Isoechoic lesion, detectable only by a hypoechoic rim

• Possible displacement or infiltration

Fig. 356 Isoechoic hepatic metastases (M) from pancreatic carcinoma. The lesions are demarcated from normal liver tissue only by a hypoechoic rim (this accounts for a certain percentage of sonographically occult metastases that are detectable by other modalities). The lesions are avascular on CDS

n Diaphragmatic crura (Fig. 357):

• Relatively echogenic band extending into the liver from the diaphragm (subcostal scan)

H Note: Diaphragmatic crura constricting the liver surface correspond to the indentations visible at laparoscopy.

Fatty Liver Echogenic

Fig. 357a, b Echogenic diaphragmatic crura (arrows). a Subcostal oblique scan. b Constriction of the liver by a diaphragmatic crus, displayed in an approximate longitudinal scan n Focal fatty infiltration (Fig. 358):

• Echogenic elliptical or tapered lesion in an otherwise normal-appearing liver

• Same location as focal sparing (gallbladder bed, periportal region)

Echogenic Uss

Fig. 358 Focal fatty infiltration (arrows), typical location adjacent to the gallbladder bed: elliptical echogenic structure. GB = gallbladder n Echogenic ligamentum teres (Fig. 359):

• Rounded, triangular, or elliptical structure between the right and left anatomic lobes of the liver (in the subcostal scan), or

Anterior Gallbladder Wall Foci
hedral figure at the end of the umbilical branch (U) of the portal vein (PV). 252 b Longitudinal scan shows the ligament coursing to the anterior abdominal wall

• Elongated echogenic band, located on or to the right of the midline, extending jj from the umbilical branch of the portal vein to the anterior abdominal wall .-J

n Echogenic portal tracts, "starry sky" appearance (Fig. 360):

• Normal variant; markedly echogenic portal tracts

• Fine, diffuse echogenic foci, often with associated bandlike vascular structures

Fig. 360 "Starry sky" appearance of the liver (after Rettenmaier) caused by echogenic portal tracts n Fresh hematoma:

• Patchy area with irregular margins

• Echogenic (unlike an old hematoma) n Hemangioma (Fig. 361a):

• Echogenic or isoechoic Smooth margins

Echogenic Mass Liver

Fig. 361a-d Echogenic mass in the liver. a Hemangioma (H) of the liver (L): typical echogenic, round to oval mass with smooth margins. b Metastasis from colon carcinoma: echogenic round mass with a less echogenic center. c Calcifying metastasis from colorectal carcinoma. S = acoustic shadow. d Chronic hepatic porphyria (porphyria cutanea tarda): disseminated, echogenic target lesions (arrows), no longer detectable several years later (misinterpreted initially as multiple hemangiomas). Clinical presentation: history of alcohol abuse, signs of porphyria. V = hepatic vein

Fig. 361a-d Echogenic mass in the liver. a Hemangioma (H) of the liver (L): typical echogenic, round to oval mass with smooth margins. b Metastasis from colon carcinoma: echogenic round mass with a less echogenic center. c Calcifying metastasis from colorectal carcinoma. S = acoustic shadow. d Chronic hepatic porphyria (porphyria cutanea tarda): disseminated, echogenic target lesions (arrows), no longer detectable several years later (misinterpreted initially as multiple hemangiomas). Clinical presentation: history of alcohol abuse, signs of porphyria. V = hepatic vein

• Often multiple, may contain calcifications, rarely has a peripheral rim n Metastasis from colon carcinoma, carcinoid metastasis (see Fig. 361b):

• Echogenic (or isoechoic) texture

• Often lacks a peripheral rim (not unlike a hemangioma)

• In other respects the lesion meets the standard sonographic criteria for metastases (see p. 442).

n Primary hepatic carcinoma (see Fig. 667, p. 444):

• Round echogenic lesions, generally in a setting of hepatic cirrhosis

• Lobulated contours n Echogenic lesions in porphyria (Fig. 361d):

• Multiple hemangioma- or cholangioma-like lesions of the same size

• Target pattern (hypoechoic center)

• Reversible n Calcification (Fig. 337c; Figs. 666,667, p. 444): very high-amplitude echo with an acoustic shadow (e.g., calcified hematoma, calcification or gas bubbles in an abscess, intracystic calcification) n Duct stones (see Fig. 182, p. 141):

• Intensely echogenic focus projected into a bile duct, often multiple

• Zone of acoustic shadowing

• Frequent dilatation of the bile duct n Pneumobilia (see Fig. 648, p. 433):

• String-of-beads or bandlike echogenic structure distributed along the bile ducts

• Reverberation artifacts n Hemorrhagic cyst (Fig. 362):

• Smooth margins, round shape

• Fine, floating echoes that swirl when tapped

• Echogenic clots

• Usually accompanied by other cysts

Echogenic Focus Left Lobe Liver

Fig. 362 Hemorrhagic liver cyst (C) with echogenic clotted blood (arrow), producing a complex overall echo pattern. The small original cyst is in the left lobe (L)

n Hepatic lesions with a complex echo pattern: See Fig. 363).

Complex Hepatic Cyst

Fig. 363a-d Complex masses in the liver. a Atypical hepatic hemangioma. b Traumatic rupture of the liver with heterogeneous anechoic to echogenic areas (arrows). c Zones of liquefaction in a tumor metastatic to breast carcinoma.

d Abscess formation in a metastasis from renal cell carcinoma (T, cursors)

Fig. 363a-d Complex masses in the liver. a Atypical hepatic hemangioma. b Traumatic rupture of the liver with heterogeneous anechoic to echogenic areas (arrows). c Zones of liquefaction in a tumor metastatic to breast carcinoma.

d Abscess formation in a metastasis from renal cell carcinoma (T, cursors)

n Role of sonography: Ultrasound is the most widely utilized, economical, and safest modality for hepatic imaging. Most lesions can be detected quickly and with a very high accuracy rate (> 90%).

• Vascularity: With new sonographic techniques such as harmonic imaging, power duplex scanning, and contrast-enhanced Doppler sonography, ultrasound is becoming comparable to CT angiography in its vascular imaging capabilities:

- Ultrasound can demonstrate the central artery and "spoked-wheel" pattern that are characteristic of FNH, and it can also show the "iris diaphragm" sign (peripheral-to-central enhancement) that is characteristic of hemangiomas.

- Hepatocellular carcinoma shows only a slight increase in vascularity relative to surrounding liver, whereas adenomas and malignant metastases in particular (except for neuroendocrine metastases and metastases from renal cell carcinoma and melanoma) display little or no vascularity.

• Detection of metastases: This depends on the size, echogenicity, and location of the primary tumor. Ultrasound has a > 80% accuracy rate in the detection of metastases that are not much smaller than 1 cm.

• Detection of cysts (intensely hypoechoic lesions): Cysts can be identified sono-graphically with no need for other imaging studies. 255

• Typical echogenic hemangiomas (75% are homogeneously echogenic), focal sparing in fatty infiltration, and typical metastases (from a known primary tumor) can also be positively identified with ultrasound. Newly detected hemangiomas require at least a 6 month sonographic follow-up. If they are > 3.5 cm, additional imaging modalities should be used.

• FNH: When the examination includes CDS, this lesion can be diagnosed sono-graphically in 70 % of cases based on the typical criteria of a stellate scar and spoked-wheel pattern. Thirty percent of lesions are atypical.

n Further investigations:

• FNAB with fine-needle histology:

- Advantages: cost-effective, largely free of side effects, relatively short examination time; a routine procedure for experienced examiners

- Indications: all indeterminate circumscribed lesions: abscess (complete removal), FNH, hematoma, and malignant tumors

- Exceptions: suspected echinococciasis, superficial metastases, and heman-gioma or adenoma (because of the risk of uncontrolled bleeding)

- Indications: hemangiomas, focal sparing, and metastases that have an isoe-choic or atypical appearance. Often these lesions cannot be adequately evaluated with ultrasound, and CT should be used in all suspected cases. CT is also indicated in patients with a suspected primary hepatic carcinoma.

- Features of primary hepatocellular carcinoma: Tumor often contains hemorrhagic areas with attenuation values < 30 HU that do not enhance after intravenous contrast administration. Hypodense tumors show marked contrast enhancement and become hyperdense in the arterial phase.

• CT angiography: used in sonographically equivocal cases that show evidence of hemangioma, adenoma, or FNH

- Adenoma: hypodense mass that may contain hemorrhagic areas; enhances rapidly, becoming hyperdense in the arterial phase. Enhancement slowly fades over a period of 3-10 min.

- FNH: hypodense mass that contains a pathognomonic central scar in 30-40 % of cases. On dynamic CT, it enhances very rapidly to hyperdensity in the arterial phase and fades rapidly to low attenuation within 1-2 min.

- Hemangioma: hypodense mass with ill-defined margins and attenuation values of 35-55 HU on unenhanced CT scans. On dynamic CT, peripheral "puddle" enhancement occurs in the early arterial phase (80% of cases). Shows peripheral-to-central fill-in at the start of the portal phase ("iris diaphragm" sign)

• MRI: may be used in cases with equivocal sonographic findings, an unknown primary tumor, or primary hepatocellular carcinoma:

- Primary hepatocellular carcinoma: hypointense to the liver parenchyma on T1-weighted images, hyperintense on T2-weighted images. Difficult to distinguish from other hepatic lesions

- Hemangioma: T2-weighted spin-echo sequence shows very high signal intensities, which persist in multi-echo sequences even as T2-weighting is increased. Useful in differentiating hemangioma from other focal hepatic changes

- Hemangioma: irregular reddish mass (when in an accessible, superficial location)

- Other indications: unexplained ascites; unexplained hepatic cirrhosis; differ- jg entiation of hepatic cirrhosis, hepatic metastases, FNH, and tuberculosis. .-J May be carried out before metastasectomy n Ultrasound-guided therapeutic intervention: ethanol injection for inoperable primary hepatic carcinoma (see also p. 60)

- Same preparations as for FNAB (p. 58)

- Instillation of 4-10mL of 96% ethanol for small lesions (or 20-180 mL for extensive lesions) at a single point or in a fan-shaped pattern under continuous vision under local resp. general anesthesia

- The injection needle is left in place for 3-5 min, then withdrawn stepwise.

• Complications: pain (peritoneal irritation), fever due to tumor necrosis

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  • Max
    What is echogenic rim and distal acoustics masses?
    3 years ago

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