Figure 2.

43-year-old patient with acute pyelonephritis (APN). Small non-enhancing hypo density (arrow – no significant change in HU) is seen in the posterior cortex of left midpole region (arrow) – suggestive of renal abscess (A – plain, B – arterial phase, C – venous phase). On axial diffusion-weighted imaging of the same patient the lesion appears progressively hyperintense with increasing b values (D, E, F, respectively). Apparent diffusion coefficient map (G) demonstrates hypointense signal with markedly decreased ADC values as compared to the APN lesions (mean ADC in the lesion measures ADC of 669 × 10^-6 mm²/s)