Prospective comparison of T2w-MRI and dynamic-contrast-enhanced MRI, 3D-MR spectroscopic imaging or diffusion-weighted MRI in repeat TRUS-guided biopsies.
OBJECTIVE
To compare T2-weighted MRI and functional MRI techniques in guiding repeat prostate biopsies.


METHODS
Sixty-eight patients with a history of negative biopsies, negative digital rectal examination and elevated PSA were imaged before repeat biopsies. Dichotomous criteria were used with visual validation of T2-weighted MRI, dynamic contrast-enhanced MRI and literature-derived cut-offs for 3D-spectroscopy MRI (choline-creatine-to-citrate ratio >0.86) and diffusion-weighted imaging (ADC × 10(3) mm(2)/s < 1.24). For each segment and MRI technique, results were rendered as being suspicious/non-suspicious for malignancy. Sextant biopsies, transition zone biopsies and at least two additional biopsies of suspicious areas were taken.


RESULTS
In the peripheral zones, 105/408 segments and in the transition zones 19/136 segments were suspicious according to at least one MRI technique. A total of 28/68 (41.2%) patients were found to have cancer. Diffusion-weighted imaging exhibited the highest positive predictive value (0.52) compared with T2-weighted MRI (0.29), dynamic contrast-enhanced MRI (0.33) and 3D-spectroscopy MRI (0.25). Logistic regression showed the probability of cancer in a segment increasing 12-fold when T2-weighted and diffusion-weighted imaging MRI were both suspicious (63.4%) compared with both being non-suspicious (5.2%).


CONCLUSIONS
The proposed system of analysis and reporting could prove clinically relevant in the decision whether to repeat targeted biopsies.
Portalez
Daniel
D
Department of Radiology, Clinique Pasteur, 45, avenue de Lombez, 31300 Toulouse, France.
Rollin
Gautier
G
Leandri
Pierre
P
Elman
Benjamin
B
Mouly
Patrick
P
Jonca
Frédéric
F
Malavaud
Bernard
B
D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D001707:Biopsy, Needle / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009942:Organometallic Compounds; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional / Q000379:methods*
D014408:Biomarkers, Tumor; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine