Functional evaluation of the remaining kidney in kidney donors by radionuclide dynamic imaging using a graphic method with factor analysis

An uptake coefficient proportional to the glomerular filtration rate (GFR) can be estimated from dynamic renal images with Tc-99(m)-DTPA using Rutland's graphic method. We have developed a new method of extracting the input and retention functions by applying factor analysis to the renal dynamic images obtained with Tc-99(m)-DTPA, which we have called the 'factor uptake coefficient' (Factor UC). In the present study, we followed 13 living kidney donors (7 males, 6 females) by measuring the Factor UC in each kidney before nephrectomy and in the remaining kidney 3 weeks and 1 year after nephrectomy. The median Factor UC in the remaining kidney increased from a pre-nephrectomy value of 0.31 to 0.52 three weeks post-nephrectomy, which then remained unchanged for up to 1 year. These results indicate that functional compensation occurs following unilateral nephrectomy, and that this process is complete within 3 weeks after nephrectomy.