Objective To investigate the feasibility of virtual touch tissue quantification(VTQ) for the assessment of chronic allograft nephropathy(CAN).Methods 48 patients with normal renal function and 50 patients with CAN were checked by color Doppler and VTQ technique.All the results were compared　between two groups.Results Mean VTQ-values were significantly different between the two groups( P ＜ 0.05).ROC curve displayed that VTQ value of 2.51 m/s could be used to diagnose CAN,the sensitivity,specificity,positive predictive value and negative predictive value were 76.0％,52.1％,60.3％ and 65.7％,respectively.The diagnostic efficiency was 62.2％.Conclusions Parenchymal stiffness measured by VTQ is stable and repeatable,which can be used to diagnose patients with CAN and to monitor renal function.

Objective: To explore the role of targeted ultrasound contrast agent in the evaluation of angiogenesis in papillary thyroid carcinoma (PTC) in nude mice by constructing platelet derived growth factor receptor α (PDGFRα)-targeted ultrasound contrast agents, and to explore the effect of platelet derived growth factor (PDGF) on angiogenesis in PTC. Methods: PDGFRα-targeted ultrasound contrast agents were constructed through biotin-avidin linkage, and blank micro-bubbles were served as control group. After the siRNA-PDGF BCPAP cell line was established, well prepared BCPAP cells or siRNA-PDGF-BCPAP cells were injected subcutaneously into the back of male BABL/C nude mice. The growth of the tumors was observed closely. All tumors of the normal group and the siRNA-PDGF group were examined by PDGFRα-targeted ultrasound contrast agents or blank micro-bubbles, and the dynamic images were analyzed quantitatively by QontraXt software.All mice were sacrificed after ultrasonography. Microvessels density (MVD) in the tumors was counted by CD31 staining and the expressions of vascular endothelial growth factor(VEGF) and PDGF were detected by Western Blot. Results: PTCs in nude mice were enhanced well by PDGFRα-targeted ultrasound contrast agent or blank micro-bubbles. The peak of tumors in siRNA-PDGF group was significantly lower than that in the normal group [(43.085±13.244)% vs (57.428±10.952)%, P=0.004]; MVD of the siRNA-PDGF group was significantly less than that of the normal group [(23.200±6.017)strips/view vs (35.000±8.456)strips/view, P=0.012]. The protein expression of PDGF and VEGF in siRNA-PDGF group were significantly lower than those in the normal group, respectively (0.142±0.058 vs 0.269±0.102, P=0.002; 0.096±0.036 vs 0.158±0.072, P=0.016). Conclusions PDGF plays an important role in angiogenesis of PTC, it maybe a new ultrasound molecular imaging method for monitoring tumor angiogenesis.