Prostate MRI: diffusion-weighted imaging at 1.5T correlates better with prostatectomy Gleason grades than TRUS-guided biopsies in peripheral zone tumours
- 635 Downloads
To investigate the usefulness of Apparent Diffusion Coefficients (ADC) in predicting prostatectomy Gleason Grades (pGG) and Scores (GS), compared with ultrasound-guided biopsy Gleason Grades (bGG).
Twenty-four patients with biopsy-proven prostate cancer were included in the study. Diffusion-weighted images were obtained using 1.5-T MR with a pelvic phased-array coil. Median ADC values (b0,500,1000 s/mm²) were measured at the most suspicious areas in the peripheral zone. The relationship between ADC values and pGG or GS was assessed using Pearson’s coefficient. The relationship between bGG and pGG or GS was also evaluated. Receiver operating characteristic (ROC) curve analysis was performed to assess the performance of each method on a qualitative level.
A significant negative correlation was found between mean ADCs of suspicious lesions and their pGG (r = −0.55; p < 0.01) and GS (r = −0.63; p < 0.01). No significant correlation was found between bGG and pGG (r = 0.042; p > 0.05) or GS (r = 0.048; p > 0.05). ROC analysis revealed a discriminatory performance of AUC = 0.82 for ADC and AUC = 0.46 for bGG in discerning low-grade from intermediate/high-grade lesions.
The ADC values of suspicious areas in the peripheral zone perform better than bGG in the correlation with prostate cancer aggressiveness, although with considerable intra-subject heterogeneity.
• Prostate cancer aggressiveness is probably underestimated and undersampled by routine ultrasound-guided biopsies.
• Diffusion-weighted MR images show good linear correlation with prostate cancer aggressiveness.
• DWI information may be used to improve risk-assessment in prostate cancer.
KeywordsMagnetic resonance imaging Prostate cancer Diffusion magnetic resonance imaging Biopsy biological markers
- 1.Society AC (2009) Cancer facts and figures 2009. Available at http://www.cancer.org/Research/CancerFactsFigures/cancer-facts-figures-2009. Accessed September 1, 2011
- 7.Gleason DF, Mellinger GT (1974) the Veterans administration cooperative urological research group: prediction of prognosis for prostatic adenocarcinoma by combined histological grading and clinical staging(ed)^(eds), pp 58–64Google Scholar
- 14.Stav K, Merald H, Leibovici D, Lindner A, Zisman A (2007) Does prostate biopsy Gleason score accurately express the biologic features of prostate cancer?(ed)^(eds). Elsevier, pp 383–386Google Scholar
- 28.Padhani AR, Liu G, Mu-Koh D et al (2009) Diffusion-weighted magnetic resonance imaging as a cancer biomarker: consensus and recommendations. Neoplasia (New York, NY) 11:102Google Scholar
- 39.Smith JJA, Scardino PT, Resnick MI, Hernandez AD, Rose SC, Egger MJ (1997) Transrectal ultrasound versus digital rectal examination for the staging of carcinoma of the prostate: results of a prospective, multi-institutional trial. J Urol 157:902–906. doi: 10.1016/s0022-5347(01)65079-1 PubMedCrossRefGoogle Scholar