Focal liver lesions (FLLs) are common on conventional ultrasound.
Contrast-enhanced ultrasound (CEUS) is highly accurate for
differentiating between benign and malignant FLLs, with an accuracy
comparable to that of contrast-enhanced CT and contrast-enhanced
MRI. Notably, there is no evidence supporting the routine use of
CEUS for evaluating benign and malignant FLLs in Switzerland. In
this study, we assessed the use of CEUS in a clinical routine
setting in a tertiary Swiss gastroenterology centre.
We analysed all CEUS investigations performed on new or unclear FLLs
in our department between November 2011 and March 2013. In all
patients, the CEUS results (benign versus malignant FLLs) were
compared with CT or MRI findings. To avoid interobserver variation,
CEUS was performed by a single experienced gastroenterologist using
one ultrasound device (Acuson Sequoia 512®, Siemens,
Erlangen, Germany). All patients were examined using the intravenous
application of 1.5–2 ml Sonovue®. An FLL with
arterial enhancement with wash-out in any vascular phase was defined
as a malignant FLL. Malignant FLLs were confirmed by histology.
The study included 112 patients. None of them experienced side
effects after injection of Sonovue®. The final diagnoses
included malignant FLLs (n = 37) and benign FLLs (n = 75) that
ranged in size from 7 to 120 mm. The biopsy-proven malignant FLLs (n
= 37) included hepatocellular carcinoma, metastatic cancers,
peripheral cholangiocarcinoma and primary B-cell lymphoma. CEUS
correctly identified 36 out of 37 malignant FLLs, showing a
sensitivity of 96–97.2% and a negative predictive value
(NPV) of 94.1–98.5%. In contrast, CT/MRI did not identify
three metastatic cancers, one HCC, one peripheral cholangiocarcinoma
and one primary lymphoma in the liver as malignant FLLs, resulting
in a sensitivity of 80.6–80.9% and an NPV of
78.9–89.8%. All these malignant FLLs were correctly
classified by CEUS.
In daily clinical practice, CEUS is a fast imaging tool which uses a
renal-independent contrast agent and shows excellent accuracy for
differentiating between malignant and benign FLLs in about five
minutes. The use of CEUS helps to avoid false negative results from
CT/MRI and improves sensitivity. CEUS should be the first diagnostic
step for investigating new or unclear FLLs.