kwartalnik polskiego towarzystwa ultrasonograficznego

arterial and portal venous / sinusoidal phase by contrast
enhanced ultrasound allows for reliable differentiation
between fnH and Hca. this important finding
could be explained by the lack of portal veins in Hca in
contrast to fnH which presents (atypical) portal veins
in many but not all patients. fnH typically appears
Characterization of focal liver lesions in non-cirrhotic liver
as a hyper-perfused tumour-like lesion relative to the
surrounding liver tissue in the arterial phase. During
the portal venous phase fnH is slightly hyperechogenic
in comparison to the surrounding liver parenchyma
[figure 3].
Table 8. Patient characteristics and sonographic findings in 32 patients with histologically proven FNH and hepatocellular
adenoma examined with SonoVue® [(11)].
fnH Hca
number 24 8
Male / female 2 / 22 0 / 8
age [years] 37 ± 10 [18 - 64] 37 ± 10 [23 – 47]
size of lesion [mm] 55 ± 21 [26 - 110] 32 ± 15 [15 – 55]
conventional B-mode ultrasound
Echo texture
Hypoechoic 7* 4*
Isoechoic 16 4
Hyperechoic 1
Central scar 10 0
colour / Power Doppler imaging
Hypervasular 23 8
Radial vascular architecture 10 0
Arterial phase hyperenhancement 24 8
(Early) Portal venous phase hyperenhancement 23 0
*all in a sonographically bright liver
Hepatocellular adenoma (HCA)
Hepatocellular adenoma exhibit arterial hyperperfusion
but no portal venous enhancement, see fnH.
Focal fatty lesion (regional focal fatty infiltration)
focal fatty changes in the liver may simulate mass
lesions, thus focal hepatic lesions might be mistaken for
hepatic neoplasm at ultrasound. this is important to
know, when it comes to a differential diagnosis. cEUs is
helpful to rule out malignant infiltration. in the arterial
and venous phase the supplying and draining vessels
of the liver hilum can be imaged. in the enhanced echo
signal sequence, different fatty degeneration regions are
imaged like normal liver tissue in the capillary and portal
venous phase. therefore, in the portal venous phase
these lesions are indistinguishable from background.
cholangiocellular carcinoma (ccc)
in the arterial phase the perfusion pattern is variable
in ccc, but mainly hyperperfused; in the late portal
venous phase ccc are hypoechoic.
Metastases
contrast enhanced ultrasound has markedly improved
the detection rate of liver metastases [(10;12)].
Metastases may be contrasted already in the arterial
phase (“halo sign”, “rim sign”). liver metastases can
be reliably diagnosed as hypoenhancing lesions during
the (liver specific) portal venous sinusoidal phase
[figure 4]. false negative findings are rarely encountered
whereas false positive findings have to be ruled out
by puncture and histological examination, e.g. abscess,
necrosism fibrous tissue and others. Unlike the portal
venous “black spot” effect of metastases, as a rule large
haemangiomas show a decrease in the unenhanced signal
area (the iris diaphragm phenomenon). any differential
diagnosis must take into account complications
of the underlying disease, and complications of therapy
(e.g. neutropenia with bacterial and/or mycotic abscesses).
Benign growths are found with the same frequency
(5–20%) as in a healthy population (for example liver
cysts, calcifications, haemangiomas, fnH, hepatocellular
adenomas).
ULTRASONOGRAFIA nr 34, 2008 23