OBJECTIVE - Urinary radiotracer excretion of (68)Ga-Labelled prostate-specific membrane antigen (PSMA) ligands may complicate the assessment of the prostate region and differentiation of lymph nodes from ureteral activity.
The aim of this study was to assess the value of delayed imaging after forced diuresis.
MATERIALS AND METHODS - Sixty-six patients underwent (68)Ga-PSMA I&T PET/CT for evaluation of prostate cancer at 60 min post-injection. In subgroups of patients, this was amended by delayed imaging after 180 min post-injection, preceded by furosemide and oral hydration early, at the time of tracer injection, or delayed, at 100 min post-injection. Urinary tracer activity within the bladder and focal ureteral activity was analyzed.
RESULTS - After forced diuresis, linear and focal visualization of ureters was significantly reduced. After delayed furosemide, mean and peak bladder activity decreased (p < 0.001), and image quality of the prostate region improved on delayed images (p < 0.001). Early furosemide co-injection with tracer resulted in increased mean and peak bladder activity (p < 0.001) and in deteriorated image quality of the prostate region on delayed images (p = 0.008).
CONCLUSIONS - Ga-PSMA I&T PET/CT delayed imaging after forced diuresis can improve the assessment of prostate region and pelvic lymph nodes by removing excreted tracer from the lower urinary tract.
KEY POINTS - • Forced diuresis can improve image quality in (68) Ga-PSMA I&T. • After forced diuresis, linear and focal visualization of ureters was reduced. • Timing of diuresis relative to (68) Ga-PSMA I&T injection is important. • Early furosemide co-injection with tracer resulted in deteriorated image quality on delayed images. • After delayed furosemide, image quality improved on delayed images.
European radiology. 2016 Mar 24 [Epub ahead of print]
Thorsten Derlin, Desiree Weiberg, Christoph von Klot, Hans-Jürgen Wester, Christoph Henkenberens, Tobias L Ross, Hans Christiansen, Axel S Merseburger, Frank M Bengel
Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625, Hannover, Germany. Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625, Hannover, Germany., Department of Urology and Urologic Oncology, Hannover Medical School, Hannover, Germany., Pharmaceutical Radiochemistry, Technische Universität München, Garching, Germany., Department of Radiation Oncology, Hannover Medical School, Hannover, Germany., Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625, Hannover, Germany., Department of Radiation Oncology, Hannover Medical School, Hannover, Germany., Department of Urology, Campus Lübeck, University Hospital Schleswig-Holstein, Lübeck, Germany., Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625, Hannover, Germany.