Noninvasive evaluation of renal allograft fibrosis by virtual touch tissue quantification

Abstract

Objective To evaluate the diagnostic value of virtual touch tissue quantification (VTQ) in the diagnosis of renal allograft fibrosis. Methods The renal allografts of 82 patients with biopsies or nephrectomy were assessed by virtual touch quantification. The renal allograft fibrosis was categorized according to the 2005 updated Banff criteria for a G0~G3 grade.All the results were compared among four groups. Results The mean SWV values in G0~G3 were (2.39±0.31)m/s, (2.45±0.34)m/s, (2.58±0.18)m/s, (3.11±0.40)m/s, respectively. There were no significant differences in the mean SWV value between G0 and G1 group, or between G1 and G2 group(P>0.05). There were significant differences in the mean SWV value between G0~G2 and G3 group, or between G0 and G2 group(P<0.05). Stiffness of renal allograft was significantly correlated to the mean SWV value ( Spearman r=0.671, P<0.001). According to the area under the ROC curve, the sensitivity and specificity of SWV (area under ROC curve=0.847, cut-off=2.64 m/s ) for grade ≥G2 was 78.9% and 79.5% respectively. Conclusions Stiffness measured by VTQ reflects the interstitial fibrosis in renal allograft.VTQ technique might be a new tool to identify patients with chronic allograft injury. Key words: Ultrasonography; Kidney transplantation; Fibrosis; Virtual touch tissue quantification