Indeterminate, subcentimetric focal liver lesions in cancer patients: Additional role of contrast-enhanced ultrasound

Purpose: To evaluate whether the use of contrast-enhanced ultrasound (CEUS) could improve the characterization of indeterminate subcentimetric focal liver lesions (FLLs) seen with multidetector computed tomography (MDCT) in cancer patients. Materials and Methods: For 12 months all patients with extrahepatic tumors showing small (<10 mm), indeterminate focal liver lesions on whole-body or abdominal computed tomography (CT) underwent immediate, targeted ultrasound (US) to rule out a cystic lesion. Whenever unenhanced US demonstrated a non-cystic lesion or failed to recognize any focal abnormality within the suspected area, CEUS was carried out. During the arterial phase, CEUS was focused on the area reflecting the CT finding, while the entire organ was explored during the portal-sinusoidal phase. Results: Among the 132 patients with MDCT evidence of indeterminate, subcentimetric focal liver lesions (206 lesions), US proved the cystic nature of 138 lesions in 87 patients. In 45 cases US failed to recognize any abnormality or cystic image and these subjects underwent CEUS. The CEUS results were confirmed by further assessment or follow-up for 43 / 45 patients (3 cysts, 8 hemangiomas, 47 metastases, 2 areas of focal steatosis, 2 eosinophilic necroses, 1 granuloma, 1 abscess, 1 fistula). CEUS failed to detect 3 lesions (1 metastasis and 2 benign lesions). In 8 cases CEUS recognized additional liver metastases. Conclusion: CEUS can be helpful in demonstrating or excluding metastases in cancer patients with MDCT evidence of subcentimetric, indeterminate focal liver lesions.