Chan Kyo Kim MD, Presenter: Nothing to Disclose

Byung Kwan Park MD, Abstract Co-Author: Nothing to Disclose

Hyun Moo Lee MD, Abstract Co-Author: Nothing to Disclose

Ghee Yong Kwon MD, Abstract Co-Author: Nothing to Disclose

To investigate the diagnostic performance of high b-value diffusion MR imaging (b=1000 and 2000 s/mm²) at 3T for predicting localized prostate cancer

Forty-eight patients with elevated PSA level were imaged in a 3 Tesla MR system using a phased-array coil, followed by radical prostatectomy. Diffusion-weighted imaging (DWI) was performed with a single-shot EPI sequence with two high b-values (1000 and 2000 s/mm²), which apparent diffusion coefficient (ADC) maps were calculated. MR images were analyzed by visual and quantitative assessment at ADC maps. ADC values at b=1000 and 2000 s/mm² were measured in benign and malignant tissues in peripheral zone (PZ) and transition zone (TZ). An ADC ratio was computed as the ratio of the mean ADC within the malignant tissue to the mean ADC within the benign tissue. For a visual assessment, the prostate was divided into 10 PZs and four TZs. For the presence of cancer in 14 sectors, two radiologists in consensus evaluated ADC maps of b=1000 and 2000 s/mm² in a different reading session.

For predicting of prostate cancer, the sensitivity and accuracy at b=1000 vs. 2000 s/mm² were 88% vs. 71% and 89% vs. 86%, respectively (P<0.01). Mean ADC values of malignant versus benign tissues in PZ were 1.19 ± 0.33 vs. 2.04 ± 0.34 at b=1000 s/mm² (P<0.001), and 1.58 ± 0.41 vs. 2.61 ± 0.36 x 10¯³mm²/s at b=2000 s/mm² (P<0.001), respectively. Mean ADC values of malignant vs. benign tissues in TZ were 1.21 ± 0.23 vs.1.87 ± 0.30 at b=1000 s/mm² (P<0.001), and 1.63 ± 0.30 vs. 2.36 ± 0.37 x 10¯³mm²/s  at b=2000 s/mm² (P<0.001), respectively. For ADC ratio at b=1000 vs. 2000 s/mm² , PZ cancer showed 0.59 ± 0.15 vs. 0.61 ± 0.15 and TZ cancer showed 0.65 ± 0.11 vs. 0.69 ± 0.12, respectively.

DWI using b=1000 & 2000 s/mm² enables improved differentiation of malignant and benign tissues in both PZ and TZ. However, DWI using b=1000 s/mm² is more sensitive and accurate than that using b=2000 s/mm² for the prediction of localized prostate cancer.

DWI using b=1000 s/mm² is more sensitive and accurate than that of b=2000 s/mm² for the prediction of localized prostate cancer.

Kim, C, Park, B, Lee, H, Kwon, G, High b-Values Diffusion MR Imaging in Prostate Cancer at 3 T: Visual and Quantitative Comparisons between b=1000 and 2000 s/mm².  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6013983.html