Renal hydronephrosis is a severe clinical disorder that results in complete renal obstruction, i.e., kidney failure. This obstruction status is diagnosed by a renal scintigraphy procedure in terms of partial or severe levels, but it fails to provide quantitative measures of its range. This study introduces one supporting parameter, ‘density count’ that provides quantitative measures of renal obstruction stages. Image extraction transforms, namely FFT-HP, Wavelet, and Harr-like, were applied to the renal scan, and the density of radiotracer present till the end of the procedure (due to obstruction) inside the kidney was measured. This transform was applied to 60 patients renal scan samples with a mean age of 25.40 ± 14. These 60 samples included 30 cases, each categorized as having a left kidney (LK) and a right kidney (RK) with a gender ratio (M/Fe:10:20) and reported as having hydronephrosis conditions. Statistical interpretation and clinical validation of the transform’s output were tested by applying Spearman’s correlation and regression coefficients, respectively, among density counts and radiotracer uptake counts provided by Gamma scintigraphy, and analysis found that density counts measured by the FFT method in the cases of LK and RK had a strongly positive correlation with radiotracer uptake counts (ρ = 0.90, 0.94) in comparison with wavelet (ρ = 0.87, 0.87) and Harr-like (ρ = 0.88, 0.70) transforms, respectively. The research highlights the importance of quantitative measurements in assessing renal obstruction levels and supports the use of the FFT transform as a valuable tool in providing accurate density counts for clinical evaluation.