To Investigate The Clinical Value Of Virtual Touch Tissues Quantification In Assessment Of The Renal Cortical Stiffness

BackgroundRenal transplantation is considered the effective treatment to be offered to patient with Chronic Renal Insufficiency. However, Renal allograft fibrosis characterized by interstitial fibrosis (IF) and tubular atrophy (TA), excessive deposition of extracellular matrix in renal glomerular and tubular interstitial, is the leading cause of graft loss as the consequence of various predisposing factors recurrent and sustained stimulation.Virtual Touch Tissues Quantification (VTQ), given as a shear wave velocity, is a new ultrasound imaging modality to assessing tissue stiffness. The aim of this study was to investigate the clinical value of ARFI quantification in assessment of the renal cortical stiffness.Objection:1. To explore the value of VTQ quantification in the diagnosis of renal allograft fibrosis and analyze its advantages and limitations.2. To get the cut-off value of the grade of renal fibrosis by measuring the ROC (Receiver Operator Characteristic) curve. Providing reference for the clinical noninvasive assessment of chronic renal allograft fibrosis and treatment formular.3. To compare the relationship between VTQ value, resistance index,the estimated glomerular filtration rate and renal allograft fibrosis.Materials and Methods:From August2010to February2012,54patients with renal allograft biopsies or nephrectomy were performed in Hospital. All the renal allograft undergoing biopsies or nephrectomy were assessed by Virtual Touch quantification of Siemens-Acuson S2000within a close time window (<3day) and serum creatinine were recorded at the same time. According to the Banff2005-classification, the patient group was classified by converting the grade of fibrosis of renal allograft biopsies into a percentage.Result:The mean values of VTQ in grade0-grade3were2.47±0.25m/s、2.64±0.23m/s、3.03±0.21m/s、3.37±0.26m/s,respectively.There were no significant difference between the VTQ in grade0and grade1subgroup. There were significant differences between the grade0-1subgroup, grade2and grade3. Stiffness was significantly correlated to the shear wave velocity and mild correlated to the resistance indices, inversely correlated to the estimated glomerular filtration rate. ROC curves were obtained, the optimal cut-off value for differential diagnosing renal allograft injury from normal renal allgraft was2.66m/s,with a sensitivity of90%,specificity of78.6%,and2.76m/s for grade0-1vs grade2-3,with a sensitivity of83.3%,specificity of96.4%,and3.26m/s for grade0-2vs grade3, with a sensitivity of95.0%,specificity of75.0%.Conclusion:VTQ is a new technique, simple and practical, easy to operate in the assessment of renal allograft fibrosis. The optimal cut-off value for differential diagnosing mild allograft fibrosis from normal renal allgraft was2.66m/s, and2.76m/s for moderate allograft fibrosis from mild allograft fibrosis, and3.26m/s for severe allograft fibrosis from moderate allograft fibrosis.