Figure 6.

PET and MR of acute renal cyst infection. MR (top) and PET/CT images (bottom) of patient with kidney transplantation due to autosomal-dominant polycystic kidney disease and suspected complicated urinay tract infection. Imaging revealed upregulated CXCR4 expression in 2 cysts (white arrow) showing renal cyst infection. Corresponding MRI confirms a cyst with thick wall (T2-weighted MRI, red arrow) and apparent diffusion coefficient (ADC) reduction in both areas, consistent with PET findings. Allograft in right lower abdomen, however, shows no signs of infection with low homogeneous ⁶⁸Ga-Pentixafor signal. MRI shows linear ADC reduction and volume loss, consistent with scarring at upper pole. MIP = maximum-intensity projection. Modified from Derlin et al ¹⁶, copyright 2017 by the Society of Nuclear Medicine and Molecular Imaging, Inc.