Figure 4. Hydronephrosis of the right kidney and pyonephrosis of the left kidney. (a) Coronal turbo spin echo (TSE) T₁ weighted image. Low signal intensity of the dilated right and left collecting systems. (b) Diffusion-weighted spin-echo echo planar imaging (SE EPI) image with b=0 s mm^–2. Slight hyperintensity of the renal pelvis of right and left kidney. (c) Diffusion-weighted SE EPI image with b=500 s mm^–2. Very low signal intensity of the right renal pelvis. Marked hyperintensity of the renal pelvis of the left kidney, indicative of restricted diffusion. (d) Apparent diffusion coefficient (ADC) map. The ADC value measured at the right dilated hydronephrotic renal pelvis is 3.39±0.48 x 10^–3 mm² s^–1, while the ADC value measured at the left dilated renal pyonephrotic pelvis is 0.77±0.17 x 10^–3 mm² s^–1.