Background
T2-weighted imaging (T2-WI) information has been used in a qualitative manner in the assessment of prostate cancer. Quantitative derivatives (T2 relaxation time) can be generated from T2-WI. These outputs may be useful in helping to discriminate clinically significant prostate cancer from background signal. Purpose/Hypothesis
To investigate changes in quantitative T2 parameters in lesions and noncancerous tissue of men on active surveillance for prostate cancer taking dutasteride 0.5 mg or placebo daily for 6 months. Study Type
Retrospective. Population/Subjects
Forty men randomized to 6 months of daily dutasteride (n = 20) or placebo (n = 20). Field Strength/Sequence
Multiparametric 3T MRI at baseline and 6 months. This included a multiecho MR sequence for quantification of the T2 relaxation times, in three regions of interest (index lesion, noncancerous peripheral [PZ] and transitional [TZ] zones). A synthetic signal contrast (T2Q contrast) between lesion and noncancerous tissue was assessed using quantitative T2 values. Signal contrast was calculated using the T2-weighted sequence (T2W contrast). Assessment
Two radiologists reviewed the scans in consensus according to Prostate Imaging Reporting and Data System (PI-RADS v. 2) guidelines. Statistical Tests
Wilcoxon and Mann–Whitney U-tests, Spearman's correlation. Results
When compared to noncancerous tissue, shorter T2 values were observed within lesions at baseline (83.5 and 80.5 msec) and 6 months (81.5 and 81.9 msec) in the placebo and dutasteride arm, respectively. No significant differences for T2W contrast at baseline and after 6 months were observed, both in the placebo (0.40 [0.29–0.49] vs. 0.43 [0.25–0.49]; P = 0.881) and dutasteride arm (0.35 [0.24–0.47] vs. 0.37 [0.22–0.44]; P = 0.668). There was a significant, positive correlation between the T2Q contrast and the T2W contrast values (r = 0.786; P < 0.001). Data Conclusion
The exposure to antiandrogen therapy did not significantly influence the T2 contrast or the T2 relaxation values in men on active surveillance for prostate cancer. |