Pilot Study of Contrast-Enhanced Ultrasound of Transplanted Kidney

To check the possibility of the acquisition of a number of parameters through real-time contrast-enhanced ultrasound and sonoelastography images and to verify the correlation with pathologic results from ultrasound guided biopsy of transplanted kidney. Ten patients scheduled to perform ultrasound guided biopsy of transplanted kidney will be enrolled. The patients who have previous medical history of cardiac problem or who do not recover renal function over three days after graft surgery will be excluded. 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. From perfusion images, several regions of interest (ROIs) will be marked including main renal artery, segmental artery and renal medulla. A number of time-intensity curves (TICs) are acquired from ROIs using VueBox. The parameters acquired from time intensity curve (TIC) (i.e. arrival time, mean transit time, time to peak, basal intensity, peak intensity, area under curve, slope rate of ascending and descending curves), the date acquired from spectral Doppler ultrasound (i.e. restive index, pulsatility index) and Values of shear wave velocities of the several regions of interest acquired from Sonoelastography will be analyzed to find statistical significance in assessment of allograft nephropathy such as acute rejection or chronic allograft nephropathy. Pathologic conditions such as acute rejection may show the decrease in arrival time, peak intensity, area under curve suggesting total blood flow and accelerating slope rate, compared with non-pathologic condition.