Dynamic Renal Ptosis Demonstrated On F-18-Fdg Pet/Ct

Renal ptosis, otherwise known as nephroptosis or "floating kidney," is a condition of abnormal descent of the kidney, often asymptomatic with controversy over its clinical and therapeutic significance. The aberrant location of renal and renal collecting system activity associated with this condition may serve as a diagnostic pitfall in PET/CT interpretation. We report a case of dynamic renal ptosis demonstrated on F-18-FDG PET/CT, identified as right kidney migration from an ectopic location on attenuation correction CT images, obtained immediately after upright positioning, to the right renal fossa on subsequent PET images, obtained after approximately 10 min of supine positioning.