Combination of forced diuresis with additional late imaging in ⁶⁸Ga-PSMA-11PET/CT – an optimised imaging protocol

Ziel/Aim The aim of this study was to investigate an optimised imaging protocol combining late additional imaging with additional hydration and forced diuresis.

Methodik/Methods One group of patients underwent ⁶⁸Ga-PSMA-11-PET/CT at 90 min p.i. with 1L oral hydration beginning and 20mg of Furosemide i.v. at 1h p.i. followed by additional late imaging at 2.5h p.i. (“old” protocol). A second group received the same procedure as before, with additional hydration and 10mg of Furosemide i.v. 30min before the late imaging. 132 patients (76 “old” protocol, 56 “new” protocol) were examined with respect to urinary bladder activity (SUV_mean), PC-lesion uptake (SUV_max) and lesion contrast.

Ergebnisse/Results Bladder activity was significantly greater for the “old” protocol in the late scans compared to the “new” protocol (ratio of bladder activity (2.5h÷1.5h): 2.33 ± 1.17 vs. 1.37 ± 0.50, p < 0.0001). Increased tumour SUV_max and contrast was seen at 2.5h compared to 1.5h (p < 0.0001 “old”; p = 0.02 “new”). Increased bladder activity for the “old” protocol resulted in decreased lesion-to-bladder contrast, which was not the case for the “new” protocol. For the “old” protocol, comparing the 1.5h to 2.5h acquisitions, 4 lesions in 4 patients (4/76=5.2 % of the cohort) were visible at the post-diuresis 1.5h acquisition, but not visible at 2.5h, having been obscured as a result of the higher bladder activity. In the new protocol, 2/56 (3.6 %) of patients had lesions visible only at late imaging and two had lesions which could be better discriminated at late imaging.

Schlussfolgerungen/Conclusions The combination of diuretics and hydration is a useful method to increase the visualisation and detectability of locally recurrent PC. However, their effects do not continue sufficiently into additional late imaging, where additional diuresis and hydration is recommended to improve visibility, detection and diagnostic certainty of local recurrences.

Publication History

Article published online:
08 April 2021