Figure 4. MRI images of pediatric renal abscess and cysts. (A) On the coronal TI-weighted, contrast-enhanced image the abscess and the cysts cannot be differentiated. (B) On the axial T2-weighted image, high signal intensity can be seen in each fluid-containing mass. (C, D) Information about the nature of the contents can be obtained by comparing diffusion-weighted imagining (DWI) and apparent diffusion coefficient (ADC) measurements: on the DWI series abscess in the right kidney has high signal and low ADC indicating restricted diffusion, while the cysts in the left kidney with clear fluid content have low signal on DWI with high signal on ACD. These measurements suggest that the lesion in the right kidney is an abscess. (E) Coronal magnetic resonance urography measurement was performed, proving that the abscess and cysts were not involving the urinary tract, as the contrast agent was not visible in any of the lesions. The solid white arrows indicate the abscess, the solid white five-pointed stars show the cysts. MRI – magnetic resonance imaging; T1W – T1-weighted; T2W – T2-weighted; DWI – diffusion-weighted imagining; ADC – apparent diffusion coefficient.