Diagnostic value of contrast-enhanced ultrasonography for solitary necrotic nodule of the liver

Objective To summarize the imaging characteristics of solitary necrotic nodule of the liver (SNNL) on contrast-enhanced ultrasonography (CEUS) and to investigate the role CEUS plays in the diagnosis and differential diagnosis of SNNL. Methods Twenty-five lesions of 23 cases diagnosed with SNNL by CEUS were retrospectively analyzed for findings of ultrasonography and contrast enhancement. Results Five patients were confirmed with SNNL by pathological examination of surgically resected liver tissue; necrotic nodule was confirmed in 18 patients by ultrasonographic follow-up or other imaging methods (contrast-enhanced computed tomography or contrast-enhanced magnetic resonance imaging). In 12 of the 25 SNNL lesions, no contrast agent enhancement was observed in all phases; 13 lesions showed thin-ring enhancement around the lesions on the arterial phase images and iso-enhancement with the liver on the portal and delayed phase images without enhancement inside the lesions in all phases. Conclusion The typical imaging of SNNL on CEUS is no enhancement of the whole lesion in all phases or thin-ring enhancement around the lesion with no enhancement inside the lesion in all phases, which is helpful for the differentiation from other space-occupying lesions of the liver.