Figure 13b. Emphysematous pyelonephritis in a 49-year-old diabetic woman. (a) Longitudinal US image of the left kidney demonstrates multiple hyperechoic foci (long arrows) with dirty acoustic shadowing (short arrow), a finding that represents gas within the renal parenchyma. (b) Photograph of the cut gross specimen reveals numerous parenchymal abscesses filled with yellow-tan purulent exudate (arrows).