Tumor blood flow (TBF) measurements in prostate cancer (PCa) provide an integrative index of tumor growth, which could be important for primary diagnosis and therapy response evaluation. 15O-water PET is the non-invasive gold standard but is technically demanding. The aim of this study was to compare the accuracy of three different non-invasive strategies with an invasively measured arterial input function (BSIF): Using image-derived input functions (IDIF) from either 1) a separate heart scan or 2) the pelvic scan or 3) a populations-based input function (PBIF). Nine patients with biopsy-verified PCa scheduled for prostatectomy were included. All patients were characterized with serum levels of PSA (s-PSA), multiparametric magnetic resonance imaging (mpMRI) and post-surgical histopathology Gleason Grade. Dynamic 15O-water was performed of the heart and the pelvic area 15 minutes apart. TBF estimated from both wash-in (K1) and wash-out (k2) constants was calculated using a one-compartmental model. Results: Mean (range) s-PSA was 12 (3-27) ng/mL, Gleason Grade Group was 2.9 (1-5), k2 was 0.44 (0.007-1.2), and K1 was 0.24 (0.07-0.55) mL/mL/min. k2 (BSIF) correlated with s-PSA (r=0.86, P<0.01) and Gleason Grade Group (rho=0.78, P=0.01). BSIF, heart-IDIF and PBIF provided near-identical k2 and K1 (r>0.95, P<0.001) with slopes near unity. The correlations of BSIF and pelvic-IDIF rate constants were good (r>0.95, P<0.001), but individual errors high. In conclusion, non-invasive protocols for 15O-water PET with IDIF or PBIF accurately measures perfusion in prostate cancer and might be useful for evaluation of tumor aggressiveness and treatment response.
American journal of nuclear medicine and molecular imaging. 2018 Oct 20*** epublish ***
Lars P Tolbod, Maria M Nielsen, Bodil G Pedersen, Søren Høyer, Hendrik J Harms, Michael Borre, Per Borghammer, Kirsten Bouchelouche, Jørgen Frøkiær, Jens Sørensen
Department of Nuclear Medicine and PET Centre, Aarhus University Hospital Aarhus C, Denmark., Department of Radiology, Aarhus University Hospital Aarhus C, Denmark., Department of Histopathology, Aarhus University Hospital Aarhus C, Denmark., Department of Urology, Aarhus University Hospital Aarhus C, Denmark.