Use of Furosemide to Clear Unusual Accumulation of 18F-FDG in a Kidney with Hypertrophic Junctional Renal Parenchyma

A 49-year-old female asked for cancer screening by positron emission tomography (PET) with 18F-fluo-rodeoxyglucose (FDG) due to usually right flank pain with intermittent pyuria and hematuria. 18F-FDG PET integrated with computed tomography (CT) was performed and showed a persistent FDG activity within right renal region on both initial (one hour post injection) and delay (two hours post injection as well as post-voiding) imaging. Intravenous administration of furosemide was employed to eliminate the retained urinary FDG activity. After the diuretic intervention the suspected FDG-avid lesion disappeared on the rescanning imaging. For further investigation of possible renal pathology, she received diuretic renogram, ultrasonography and (superscript 99m)Tc-dimercaptosuccinic acid renal cortical scan and it appeared that hypertrophy of junction parenchyma seemed to be the most likely etiology leading to FDG retention within renal calyx. From this anecdotal case we suggest that diuretic intervention can be a useful measure to elucidate unusual urinary retention in renal regions noticed on FDG PET.