Washout gradient in dynamic contrast-enhanced MRI is associated with tumor aggressiveness of prostate cancer.
OBJECTIVE
To investigate the associations between dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) parameters and the Gleason score (GS) for prostate cancer (PCA) with localization information provided by concurrent apparent diffusion coefficient (ADC) maps.


METHODS
Forty-three male patients received MR scans, including diffusion tensor imaging (DTI) and DCE MRI, on a 1.5 T MR system. All patients were confirmed to have PCA in the following biopsy within 2 weeks. ADC maps calculated from DTI were used to colocalize cancerous and noncancerous regions on DCE MRI for perfusion analysis retrospectively. Semiquantitative parameters (peak enhancement, initial gradient, and washout gradient [WG] and quantitative parameters [K(trans) , ν(e) , and k(ep) ]) were calculated and correlated with the GS. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance of the perfusion parameters in assessing the aggressiveness of PCA.


RESULTS
A total of 41 PCA nodules were included in the analysis. Among all quantitative and semiquantitative parameters, only WG showed significant correlation with GS (r = -0.75, P < 0.0001). By defining tumor aggressiveness as a GS >6, WG demonstrated a good diagnostic performance, with the area under the ROC curve being 0.88. Under a cutoff point of WG = 0.125 min(-1) , the sensitivity and specificity were 0.87 and 0.78, respectively.


CONCLUSIONS
WG shows a significant association with GS and good diagnostic performance in assessing tumor aggressiveness. Therefore, WG is a potential marker of GS.
Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan.
Yu-Jen
YJ
Chen
Woei-Chyn
WC
Chu
Yeong-Shiau
YS
Pu
Shih-Chieh
SC
Chueh
Chia-Tung
CT
Shun
Wen-Yih Isaac
WY
Tseng
D000368:Aged; D000465:Algorithms; D003287:Contrast Media; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011471:Prostatic Neoplasms / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D019786:Gadolinium DTPA