Fig. 6

Partly cystic lesion on CEUS compared to gray scale ultrasound. Gray scale longitudinal ultrasound (6a) shows an apparently partly cystic lesion within a strongly echogenic kidney in a 53-year old man with advanced CKD and hence contraindications to both contrast CT and MR. The lesion demonstrates intense homogeneous enhancement on CEUS (6b) and is larger but otherwise unchanged on 21-month follow-up imaging. It appeared partly cystic on grayscale ultrasound because it was surrounded by strongly echogenic CKD tissue. This case illustrates the difficulty of differentiating tumors from benign cysts on conventional ultrasound in the setting of advanced CKD