Dados do Trabalho

Título

Dual Time PSMA PET/CT with Diuretics and Contrast to Detect Prostate Cancer Pelvic Metastases: Is There a Benefit?

Introdução/Justificativa

The renal excretion of PSMA radiotracer may render imaging interpretation of images difficult to identify local recurrence and lymph node metastases.

Objetivos

To evaluate which is the best acquisition method to increase the detection rate of local recurrence and pelvic metastases on PSMA PET/CT by performing dual time-point imaging after hyperhydration, diuretics and contrast enhancement in prostate cancer patients.

Materiais e Métodos

Patients with prior history of prostate adenocarcinoma underwent PSMA PET/CT for primary staging or due to biochemical recurrence. The acquisition consisted of delayed pelvic imaging, diuretic administration, and excretory-phase contrast. The SUV values obtained in the local recurrence lesions, locoregional lymph node metastases, and bone metastases in the early and delayed images were compared.

Resultados

A total of 182 patients underwent PSMA PET/CT. Twenty-one patients (12%) were scanned due to primary staging, and 161 patients due to biochemical recurrence (88%).
Delayed images (without contrast or diuretics) increased diagnostic certainty to identify local recurrence in 26.6% patients, locoregional lymph nodes in 25%. There was a significant increase in SUV values in the delayed images compared to early images in the regions of local recurrence (p<0.0001), locoregional lymph node metastases (p<0.0001), and bone metastases (p<0.0199).
The addition of contrast-enhancement to the delayed images increased diagnostic certainty to identify local recurrence in 9.4% patients, and locoregional lymph nodes in 8.3%. The addition of diuretics to the delayed images increased diagnostic certainty to identify local recurrence in 14% and locoregional lymph nodes in 2.8%. The association of diuretics with contrast-enhancement to the delayed images increased diagnostic certainty to identify local recurrence in 15.6% and locoregional lymph nodes in 5.6%.

Conclusão

Delayed PSMA PET/CT images increase the diagnostic certainty to identify local recurrence and locoregional metastases in prostate cancer patients. The addition of contrast enhancement and diuretics has mild impact to the delayed pelvic images and may be omitted.