Diagnostic ultrasound ( PDFDrive )

86 PART II Abdominal and Pelvic Sonography
A
B
C
D
FIG. 4.18 Acute Hepatitis. Acute hepatitis in patient with fever, abnormal liver function tests, and incidental gallstones. (A) Transverse view
of porta hepatis and (B) transverse view of left lobe of liver show thick, prominent echogenic bands surrounding the portal veins in the portal triads,
called periportal cufing. (C) Sagittal and (D) transverse views of the gallbladder show moderate edema and thickening of the gallbladder wall.
The gallbladder is not large or tense, and the patient does not have acute cholecystitis. As this case illustrates, incidental cholelithiasis may be
confusing.
are varied (Fig. 4.19A-F). Frankly purulent abscesses appear
cystic, with the luid ranging from echo free to highly echogenic.
Regions of early suppuration may appear solid with altered
echogenicity, usually hypoechoic, related to the presence of
necrotic hepatocytes. 27 Occasionally, gas-producing organisms
give rise to echogenic foci with a posterior reverberation artifact
(Fig. 4.19G-I). Fluid-luid interfaces, internal septations, and
debris have all been observed. he abscess wall can vary from
well deined to irregular and thick.
he diferential diagnosis of pyogenic liver abscess includes
amebic or echinococcal infection, simple cyst with hemorrhage,
hematoma, and necrotic or cystic neoplasm. Ultrasound-guided
liver aspiration is an expeditious means to conirm the diagnosis.
Specimens should be sent for both aerobic and anaerobic culture.
In the past, 50% of abscesses were considered sterile, probably
caused by failure to transport the specimen in an oxygen-free
container; thus anaerobic organisms were not identiied. 28 Once
the diagnosis of liver abscess is made by the identiication of
pus or a positive Gram stain and culture, the collection can be
drained percutaneously using ultrasound or CT guidance.
Fungal Diseases: Candidiasis
he liver is frequently involved secondary to hematogenous spread
of mycotic infections in other organs, most oten the lungs.
Patients are generally immunocompromised, although systemic
candidiasis may occur in pregnancy or ater hyperalimentation.
he clinical characteristics include persistent fever in a neutropenic
patient whose leukocyte count is returning to normal. 29
he ultrasound features of hepatic candidiasis include the
following 30 :
• “Wheel within a wheel”: peripheral hypoechoic zone with
inner echogenic wheel and central hypoechoic nidus. he
central nidus represents focal necrosis in which fungal elements
are found. his is seen early in the disease.
• Bull’s-eye: 1- to 4-cm lesion with hyperechoic center and
hypoechoic rim. It is present when neutrophil counts return