Figure 5. Case 9: 35-year-old male with fever of unknown origin. (a) Longitudinal ultrasound of the left kidney. Simple cyst in the mid-portion. (b) Pre-contrast CT shows a hypodense lesion in the left kidney. (c) After contrast injection no opacification is seen in the lesion. (d) 15 min after injection there is now contrast material within the diverticulum.