Impact of forced diuresis at two different time points on pelvic imaging in prostatic carcinoma with 68Ga-PSMA PET/CT.

Abstract

We compared diagnostic quality of 68Ga-PSMA PET/CT imaging focused on the pelvic structures using two furosemide protocols in two different groups of patients. A total of 55 patients with prostate cancer were retrospectively enrolled in the study. Out of 55, 31 patients were in group 1 (median age: 66 years, Range 44-78 years) in which furosemide injection was given after completion of whole-body 68Ga-PSMA PET/CT scan and 24 patients were in group 2 (median age: 63.5 years, range: 50-82 years) in which it was given along with the 68Ga-PSMA injection. In both groups, an initial time point scan (T0 scan) and a delayed time point scan (T1scan) were done. The images were analyzed qualitatively as well as quantitatively. Quantitatively there was no statistically significant difference between the SUVmax and T:B of prostatic lesion and seminal vesicle invasion (SVI) in both the groups at two time points (P > 0.05). Early furosemide injection caused a washout of the urinary bladder radiotracer concentration in significantly higher number of patients in group 2 (62.5% vs. 6.45% patients, P < 0.001). There was significant clearance of radiotracer activity from the ureters in group 2 (SUVmax: 9.28 vs. 3.09, P = 0.002). The simultaneous furosemide and 68Ga-PSMA injection can reduce the urinary excretion of the tracer and improve the diagnostic confidence of prostatic lesion, SVI and lymph nodal metastasis, along with reducing the scanning time and radiation burden, making this protocol an effective alternative to the present protocol of delayed furosemide injection.