Intra-individual comparison of (68)Ga-PSMA-11-PET/CT and multi-parametric MR for imaging of primary prostate cancer

• Published in: European journal of nuclear medicine and molecular imaging 2016-07, Vol.43 (8), p.1400-1406
• Main Authors: Giesel, F L, Sterzing, F, Schlemmer, H P, Holland-Letz, T, Mier, W, Rius, M, Afshar-Oromieh, A, Kopka, K, Debus, J, Haberkorn, U, Kratochwil, C
• Format: Article
• Language: English
• Subjects: Aged; Edetic Acid - analogs & derivatives; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Neoplasm Staging; Oligopeptides; Positron Emission Tomography Computed Tomography; Prostatic Neoplasms - diagnostic imaging; Prostatic Neoplasms - pathology
• ISSN: 1619-7089
• DOI: 10.1007/s00259-016-3346-0

Multi-parametric magnetic resonance imaging (MP-MRI) is currently the most comprehensive work up for non-invasive primary tumor staging of prostate cancer (PCa). Prostate-specific membrane antigen (PSMA)-Positron emission tomography-computed tomography (PET/CT) is presented to be a highly promising new technique for N- and M-staging in recurrent PCa-patients. The actual investigation analyses the potential of (68)Ga-PSMA11-PET/CT to assess the extent of primary prostate cancer by intra-individual comparison to MP-MRI. In a retrospective study, ten patients with primary PCa underwent MP-MRI and PSMA-PET/CT for initial staging. All tumors were proven histopathological by biopsy. Image analysis was done in a quantitative (SUVmax) and qualitative (blinded read) fashion based on PI-RADS. The PI-RADS schema was then translated into a 3D-matrix and the euclidian distance of this coordinate system was used to quantify the extend of agreement. Both MP-MRI and PSMA-PET/CT presented a good allocation of the PCa, which was also in concordance to the tumor location validated in eight-segment resolution by biopsy. An Isocontour of 50 % SUVmax in PSMA-PET resulted in visually concordant tumor extension in comparison to MP-MRI (T2w and DWI). For 89.4 % of sections containing a tumor according to MP-MRI, the tumor was also identified in total or near-total agreement (euclidian distance ≤1) by PSMA-PET. Vice versa for 96.8 % of the sections identified as tumor bearing by PSMA-PET the tumor was also found in total or near-total agreement by MP-MRI. PSMA-PET/CT and MP-MRI correlated well with regard to tumor allocation in patients with a high pre-test probability for large tumors. Further research will be needed to evaluate its value in challenging situation such as prostatitis or after repeated negative biopsies.