Quantitative characterisation of clinically significant
intra-prostatic cancer by prostate-specific membrane antigen (PSMA)
expression and cell density on PSMA-11
Received: 28 December 2017 /Revised: 26 March 2018 /Accepted: 12 April 2018
European Society of Radiology 2018
Objectives To quantitatively characterize clinically significant intra-prostatic cancer (IPC) by prostate-specific membrane antigen
(PSMA) expression and cell density on PSMA-11 positron emission tomography/magnetic resonance (PET/MR).
Methods Retrospective study approved by the institutional review board with informed written consent obtained.
Patients with a solitary, biopsy-proven prostate cancer, Gleason score (GS) ≥7, presenting for initial evaluation by
PET/computerised tomography (PET/CT), underwent early prostate PET/MR immediately after PSMA-11 tracer injec-
tion. PET/MR [MRI-based attenuation correction (MRAC)] and PET/CT [CT-based AC (CTAC)] maximal standardised
uptake value (SUVmax) and minimal and mean apparent diffusion coefficient (ADCmin, ADCmean; respectively) in
normal prostatic tissue (NPT) were compared to IPC area. The relationship between SUVmax, ADCmin and ADCmean
measurements was obtained.
Results Twenty-two patients (mean age 69.5±5.0 years) were included in the analysis. Forty-four prostate areas were evaluated
(22 IPC and 22 NPT). Median MRAC SUVmax of NPT was significantly lower than median MRAC SUVmax of IPC (p <
0.0001). Median ADCmin and ADCmean of NPT was significantly higher than median ADCmin and ADCmean of IPC (p <
0.0001). A very good correlation was found between MRAC SUVmax with CTAC SUVmax (rho = –0.843, p < 0.0001). A good
inverse relationship was found between MRAC SUVmax and CTAC SUVmax with ADCmin (rho = –0.717, p <0.0001and–
0.740, p < 0.0001; respectively; Z = 0.22, p = 0.82, NS) and with MRAC SUVmax and ADCmean (rho = –0.737, p <0.0001).
Conclusions PET/MR SUVmax, ADCmin and ADCmean are distinct biomarkers able to differentiate between IPC and NPT in
naïve prostate cancer patients with GS ≥ 7.
• PSMA PET/MR metrics differentiate between normal and tumoural prostatic tissue.
• A multi-parametric approach combining molecular and anatomical information might direct prostate biopsy.
• PSMA PET/MR metrics are warranted for radiomics analysis.
Keywords Prostate cancer
Positron emission tomography
Magnetic resonance imaging
Apparent diffusion coefficient
ADC Apparent diffusion coefficient
DCE Dynamic contrast-enhanced
DWI Diffusion-weighted imaging
FWHM Full width at half maximum
GS Gleason score
IPC Intra-prostatic cancer
MR Magnetic resonance
MRI Magnetic resonance imaging
* Liran Domachevsky
Department of Nuclear Medicine, Assuta Medical Centers, 20
Habarzel St, 6971028 Tel-Aviv, Israel
Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel