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Loria et al. CEUS in evaluation of vascularization of HCC

within the lesion, giving further diagnostic evidence of vascularization in relation to the legion depth was
malignancy. statistically significant. In particular, only 58% of the
lesions situated at a depth greater than 9 cm from the
In a multicentric study (DEGUM) with 1,349 patients with abdominal wall presented in arterial phase CEUS,
focal hepatic lesions identified with basal ultrasound, the same vascularization as with the corresponding
CEUS was compared with biopsy in 75% of the cases phase in MSCT; this contrasts with 95% of the lesions
and in the remaining 25% with spiral CT or MR. The situated more superficially.
diagnostic accuracy of CEUS was 90.3%. [23,24]
In this study, the homogeneity of the enhancement
Two other, more recent prospective studies (DEGUM) was not evaluated because this element can be
have evaluated the potential of CEUS in the extremely variable due to a number of factors.
characterization of focal hepatic lesions by comparing Particularly in the arterial phase, inhomogeneity
CEUS with CT and with MR; in both studies it was of enhancement is frequently present due to the
concluded that there are not statistically significant presence of adipose degeneration or intratumoral
differences. [25,26] necrosis. In the portal phase, a “mosaic” aspect is
often noticed, particularly in the larger lesions. [27]
In the first study the authors concluded that CEUS
must be used first, before using CT; they have also The use of CEUS also allows clinicians to differentiate
documented that CEUS utilization can considerably HCC from other benign or malignant focal hepatic
reduce the number of diagnostic biopsies. [25] lesions. [28-32]
The second study demonstrated a substantial overlap The intrinsic limitations of CEUS vary in relation to
between the vascularization documented using CEUS various patient characteristics (cooperation,obesity),
when compared with that documented using MR. [26] various characteristics of lesions (site-dimensions-
depth), and the CEUS operator. [33]
Gaiani et al. [16] have found that 91% of hypervascular
hepatocarcinoma using MSCT presented hyper- Another important CEUS limitation is that the
vascularization in arterial phase with CEUS as well, technique focuses study on a single lesion, mainly in
and that 75% of hypervascular hepatocarcinoma the arterial phase, because it can often be particularly
showed hypovascularization in portal or late phase. challenging to evaluate the enhancement of the entire
hepatic parenchyma in a short period of time. By
Xu et al. [19] reported in their series that 87% of contrast, the panoramic views of CT and MR allow
hepatocarcinoma, all with dimensions equal to or less scans to evaluate the entire hepatic parenchyma.
than 2 cm, appeared hypovascular in the portal phase,
while 46% were isovascular in the portal phase. In the 2010 AASLD guidelines for the management of
HCC, CEUS was removed from the protocol because
In this study, a high comparability was demonstrated it can give false positives in patients with intrahepatic
between CEUS and MSCT, with 88% of nodules cholangiocarcinoma. [34] However, CEUS is the only
appearing hypervascular in the arterial phase using method that allows the study of the vascularization
both methods, independently of lesion dimensions. of a single lesion “in real time”. Such a possibility
provides the advantage of accurately documenting
Two studies, however, have demonstrated that the the neoangiogenesis typical of hepatocarcinoma,
sensitivity of CEUS diagnosing HCC is in direct characterized by the formation of neoartorioles at
proportion to lesion dimensions. For the nodules with the periphery and the inside of the lesion that can
[16]
dimensions equal to or less than 2 cm, Gaiani et al. be enhanced at a very early stage. Furthermore, in
and Giorgio et al. [20] reported a 83.3% and 56.3% some cases (mainly in small-dimension lesions) such
sensitivity for CEUS, respectively. Conversely, in precocity can be transitory and thus assessable only
nodules with dimensions > 2 cm, sensitivity was in a continuous view.
significantly increased by 94% and 91%, for CEUS, in
the respective studies. Some studies have demonstrated that a certain number
of lesions, varying between 5% and 25%, remain
In this study, there were no statistically significant undetermined after a CEUS study, because they do
differences in individualization of vascularization not present a characteristic enhancement. [28-30] This
in lesions, in relation to dimensions in the arterial number can be reduced, even if not in a significant
phase. Conversely using CEUS, the evaluation of manner, if a second method of CT or MR is added to
320 Hepatoma Research ¦ Volume 2 ¦ November 22, 2016