Negative predictive value for cancer in patients with "gray-zone" PSA level and prior negative biopsy: preliminary results with multiparametric 3.0 Tesla MR.
OBJECTIVE
To investigate the negative predictive value (NPV) for malignancy of 3.0 Tesla (T) MRI in patients with "gray zone" PSA level and prior negative biopsies.


METHODS
We enrolled 26 patients with PSA level between 2.5 and 10 ng/mL and no cancer at previous biopsies. Examinations were performed on a 3.0T system using T2-weighted imaging, diffusion-weighted imaging, spectroscopy, and postcontrast dynamic study. A regional scheme was used to record MRI findings and to perform subsequent transrectal-ultrasonography-guided biopsy. Based on the matching between imaging and biopsy findings we estimated MRI predictive values, sensitivity, specificity and accuracy on a per-patient and per-region basis.


RESULTS
On a per patient basis, MRI had five true-positive (5/26; 19.2%), eight true-negative (8/26; 30.8%) and no false-negative cases, corresponding to a NPV and sensitivity of 100% each. Thirteen patients were assessed as false-positive cases (13/26; 50.0%) (specificity of 38.1%). Five of them (5/26; 19.2%) showed high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical small-acinar proliferation (ASAP) at biopsy. T2-weighted imaging alone showed per-region NPV (96.8%).


CONCLUSIONS
Because of the high NPV, MRI had the potential to avoid unnecessary biopsy in approximately one-third of "gray-zone" patients with a negative examination. Additionally, MRI was useful to address to biopsy more than one-third of patients with cancer or high-risk lesions as HGPIN and ASAP.
Institute of Diagnostic Radiology, University of Udine - Azienda Ospedaliero-Universitaria "S. Maria della Misericordia", via Colugna n. 50, 33100 - Udine, Italy. rgirometti@sirm.org
Rossano
R
Girometti
Massimo
M
Bazzocchi
Giuseppe
G
Como
Giovanni
G
Brondani
Matteo
M
Del Pin
Bruno
B
Frea
Guillermo
G
Martinez
Chiara
C
Zuiani
D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D001706:Biopsy; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen