Before ultrasound guided biopsy of transplanted kidney, we will perform conventional, Sonoelastography and real-time contrast-enhanced ultrasound using Sonovue for acquisition of parameters and data, respectively. We will check the possibility of the acquisition of a number of parameters through real-time contrast-enhanced ultrasound and sonoelastography images using analyzing program (VueBox, Bracco, Swiss). And we will verify the correlation of acquired data and parameters with pathologic results from ultrasound guided biopsy of transplanted kidney.