Application of superb microvascular imaging in the evaluation of focal liver lesions

Abstract

Objective To estimate the value of superb microvascular imaging(SMI) in the detection of microvascular flow signal of focal liver lesions(FLLs). Methods A total of 54 patients with 56 FLLs who had underwent CDFI(Color Doppler Flow imaging) and SMI were included in this study. Adler semi-quantitative assessment was used to grade the distribution of blood flow signal for each FLL by two observers, then inter-observer agreement was assessed. The distribution of blood flow grade between CDFI and SMI was also compared with contrast-enhanced ultrasound(CEUS) as the reference standard. Results The inter-observer agreement for Adler semi-quantitative grading were fair (Κ=0.579) on CDFI and good (Κ=0.605) on SMI, respectively. The grade 0, Ⅰ, Ⅱ and Ⅲ of Adler semi-quantitative grading of all total 56 FLLs' blood flow signal on three flow imaging tools were 4(7.14%), 25(42.86%), 14(25%), 14(25%)on CDFI, 0(0%), 12(21.43%), 12(19.64%), 33(58.93%) on SMI, and 0(0%), 3(5.36%), 21(37.50%), 32(57.14%) on CEUS micro-flow imaging, respectively. With CEUS blood flow distribution in the arterial phase as the reference, the coincidence rate of CDFI was 30.35%, while that of SMI was 73.21%. The distinction of ability on FLL's micro-vascular imaging between CDFI and SMI was statistically significant(P<0.01). Conclusions The inter-observer agreement of SMI was better than that of CDFI and its capacity in displaying FLL's micro-vascular was superior to CDFI, SMI can exhibit more tiny vessels and thus SMI may possess potential value in the differential diagnosis of FLLs. Key words: Ultrasonography; Focal liver lesions; Superb microvascular imaging