Usefulness of MRI-assisted metabolic volumetric parameters provided by simultaneous 18F-fluorocholine PET/MRI for primary prostate cancer characterization - Abstract

PURPOSE: The aim of this study was to determine the usefulness of MRI-assisted positron emission tomography (PET) parameters provided by simultaneous 18F-fluorocholine (FCH) PET/MRI for characterization of primary prostate cancer.

METHODS: Thirty patients with localized prostate cancer (mean age 69.4 ± 6.7 years) confirmed by biopsy were prospectively enrolled for simultaneous PET/MRI imaging. The patients underwent 18F-FCH PET/MRI 1 week before undergoing total prostatectomy. Multiple parameters of diffusion-weighted MRI [minimum and mean apparent diffusion coefficient (ADCmin and ADCmean)], metabolic PET [maximum and mean standardized uptake value (SUVmax and SUVmean)], and metabolic volumetric PET [metabolic tumor volume (MTV) and uptake volume product (UVP)] were compared with laboratory, pathologic, and immunohistochemical (IHC) features of the prostate cancer specimen. PET parameters were divided into two categories as follows: volume of interest (VOI) of prostate by SUV cutoff 2.5 (SUVmax, SUVmean, MTVSUV, and UVPSUV) and MRI-assisted VOI of prostate cancer (SUVmaxMRI, SUVmeanMRI, MTVMRI, and UVPMRI).

RESULTS: The rates of prostate cancer-positive cases identified by MRI alone, 18F-FCH PET alone, and 18F-FCH PET/MRI were 83.3, 80.0, and 93.3 %, respectively. Among the multiple PET/MRI parameters, MTVMRI showed fair correlation with serum prostate-specific antigen (PSA; r = 0.442, p = 0.014) and highest correlation with tumor volume (r = 0.953, p < 0.001). UVPMRI showed highest correlation with serum PSA (r = 0.531, p = 0.003), good correlation with tumor volume (r = 0.908, p < 0.001), and it was significantly associated with Gleason score (p = 0.041). High MTVMRI and UVPMRI values were significant for perineural invasion, lymphatic invasion, extracapsular extension, seminal vesicle invasion, and positive B-cell lymphoma 2 (Bcl-2) expression (all p < 0.05).

CONCLUSION: Simultaneous 18F-FCH PET/MRI demonstrated a better diagnostic value for localized prostate cancer detection than each individual modality. MRI-assisted metabolic volumetric PET parameters (MTVMRI and UVPMRI) provided more accurate characterization of prostate cancer than conventional PET and MRI parameters.

Written by:
Kim YI, Cheon GJ, Paeng JC, Cho JY, Kwak C, Kang KW, Chung JK, Kim EE, Lee DS.   Are you the author?
Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.

Reference: Eur J Nucl Med Mol Imaging. 2015 Mar 11. Epub ahead of print.
doi: 10.1007/s00259-015-3026-5

PubMed Abstract
PMID: 25759164 Prostate Cancer Section