Contrast-Enhanced Ultrasound: a Simple and Effective Tool in Defining a Rapid Diagnostic Work-up for Small Nodules Detected in Cirrhotic Patients during Surveillance.

Background and Aims: Disappearance of portal blood flow and arterial vascularization is the hallmark of hepatocarcinogenesis. The capability of a dynamic imaging modality detecting arterial hypervascularization of small nodules is crucial to promote a rapid diagnostic and therapeutic work-up improving survival. We aimed to evaluate the capability of CEUS to detect arterial vascularization of ≤ 2 cm HCC nodules arising during surveillance so as to shorten the diagnostic and therapeutic work-up.
Methods: From October 2009 to September 2014, among 1757 consecutive cirrhotic patients under surveillance with ultrasound (US), 243 patients had new single nodules 7-20 mm; 229/243 had a conclusive histologic diagnosis and comprised the study group. All patients underwent CEUS followed by enhanced MRI and US guided percutaneous 18G needle core biopsy of the nodules. Of the 229 nodules, 27 were hyperechoic, 171 hypoechoic and 31 isoechoic lesions.
Results: The histology results revealed that 199/229 nodules were HCC and 30 were benign. Of 199 HCC, CEUS evidenced arterial hypervascularity in 190 nodules (95.5%) (sensitivity 94.48 %, specificity 100%, PPV 100%, NPV 76.92 %). Of the 39 CEUS arterial-unenhanced nodules, 30 were benign and 9 (23%) were well-differentiated HCC. eMRI showed arterial hypervascularity in 199 nodules (86,9%). Of these, only 193 (97%) were histologically HCCs while 6 were benign (sensitivity: 97%, specificity: 80%, PPV: 97%, NPV: 80%).
Conclusions: CEUS has a great capability to detect arterial hypervascularity of small HCC. Because only 4.5% of new nodules escape the demonstration of arterial hyervascularity, CEUS must be performed immediately after conventional US to contrast the malignant fate of small lesions arising in a cirrhotic liver.