Biology Reference
In-Depth Information
(Webster and Holloway
2008
). In addition, CEUS has been very helpful for the
detection of metastatic liver nodules of hemangiosarcoma, which is undetectable
with B-mode US (O'Brien
2007
). In the dog, the hypoechogenicity of nodular
hepatic lesions at the peak liver enhancement was significantly associated with
malignancy, showing high sensitivity (100%), specificity (94.1%), positive predic-
tive value (93.8%), and negative predictive value (100%) (O'Brien et al.
2004
). The
data collected in this study regarding hepatic malignant focal lesions are similar to
those reported in the literature, with the exception of hepatocellular carcinoma in
the cat, which was isoechoic at peak liver enhancement (arterial blood phase) when
compared to the surrounding normal liver parenchyma, and became hypoechoic
during the portal blood phase. The echogenicity of the lesion at peak liver enhance-
ment was not statistically significant to discriminate a benign or malignant origin.
The hypoechogenicity during the portal blood phase was the only ultrasonographic
feature that was related to malignancy. Its sensitivity and specificity were quite
high, according to the literature in human medicine (Quaia
2007
; Nyman et al.
2004
). CEUS is always well tolerated without any side effects. Lesions' perfusion
was accurately visualized in all cases. In two cases of hepatocellular carcinoma, it
was possible to identify other hypovascular lesions during the portal phase, which
were not visible during the B-mode ultrasonographic examination.
In conclusion, CEUS of nodular hepatic lesions can be considered a diagnostic
method that is easy to perform, minimally invasive, and well tolerated. The
evaluation of the hemodynamics of the contrast medium during the vascular
perfusion of the hepatic lesions improves the diagnostic accuracy of US in the
study of malignant lesions (Haers and Saunders
2009
; Quaia
2007
; Nyman et al.
2004
). In conclusion, lesions that are hypoechoic during peak liver enhancement
and, in particular, during the portal phase are significantly associated with malig-
nancy (primary hepatic neoplasia/metastasis) (O'Brien et al.
2004
; Quaia
2007
).
However, in veterinary medicine, CEUS is unable to define clearly the cellular type
of neoplasia, due to the deficiency of reported studies on this topic in the literature.
Therefore, cyto/histological studies are still needed to make a final diagnosis in
cases of malignancy.
References
Bergman JR (1985) Nodular hyperplasia in the liver of the dog: an association with changes in the
Ito cell population. Vet Pathol 22:427-438
Haers H, Saunders JH (2009) Review of clinical characteristics and applications of contrast-
enhanced ultrasonography in dogs. J Am Vet Med Assoc 234:460-470
Ivanˇi´ M, Long F, Seiler GS (2009) Contrast harmonic ultrasonography of splenic masses and
associated liver nodules in dogs. J Am Vet Med Assoc 234:88-94
Nyman HT, Kristensen AT, Flagstad A, McEvoy FJ (2004) A review of the sonographic assess-
ment of tumor metastases in liver and superficial lymph nodes. Vet Radiol Ultrasound
45:438-448
