Value of contrast-enhanced ultrasound in differential diagnosis of single metastatic liver cancer and solitary necrotic nodule of the liver

Objective To investigate the value of contrast- enhanced ultrasound( CEUS) in the differential diagnosis of single metastatic hepatic carcinoma( MHC) and solitary necrotic nodule of the liver( SNNL). Methods A retrospective analysis was performed for 12 patients with single MHC and 16 patients with SNNL who showed circular enhancement in arterial phase on CEUS. Age,size of lesion,and findings of two- dimensional gray- scale ultrasound and CEUS were compared between the two groups. The two- independent- samples t-test was used for comparison between groups,and the paired t- test was used for comparison within each group. Results The MHC group had a significantly higher mean age than the SNNL group( 60. 2 ± 11. 3 years vs 41. 0 ± 9. 1 years,t = 4. 970,P < 0. 001). The mean diameter of lesion was 2. 86 ± 1. 22 cm in the MHC group and 2. 97 ± 0. 96 cm in the SNNL group,and showed no significant difference between the two groups( t =- 0. 269,P = 0. 790). In the MHC group,the lesions had complex and uneven echoes and blurred boundaries,while in the SNNL group,most lesions were in the right lobe and were hypoechoic with clear boundaries. No blood flow signals were detected on CDFI in these two groups. Both groups had circular enhancement around the lesions in arterial phase on CEUS,and the mean thickness showed a significant difference between the MHC group and the SNNL group( 5. 00 ± 1. 69 mm vs 2. 37 ± 0. 87 mm,t = 5. 374,P < 0. 001). In the MHC group,the area in lesions without enhancement in delayed phase was significantly larger than that in arterial phase( t =- 4. 508,P =0. 001),while in the SNNL group,the area in lesions without enhancement showed no significant difference between delayed phase and arterial phase( t =- 0. 449,P = 0. 660). Conclusion The thickness of circular enhancement in arterial phase on CEUS and the presence or absence of the enlargement in the area without enhancement contributes to the differential diagnosis of single MHC and SNNL.