Hybrid multidimensional T2 and diffusion-weighted MRI for prostate cancer detection

Purpose To study the dependence of apparent diffusion coefficient (ADC) and T2 on echo time (TE) and b‐value, respectively, in normal prostate and prostate cancer, using two‐dimensional MRI sampling, referred to as “hybrid multidimensional imaging.” Materials and Methods The study included 10 patients with biopsy‐proven prostate cancer who underwent 3 Tesla prostate MRI. Diffusion‐weighted MRI (DWI) data were acquired at b = 0, 750, and 1500 s/mm2. For each b‐value, data were acquired at TEs of 47, 75, and 100 ms. ADC and T2 were measured as a function of b‐value and TE, respectively, in 15 cancer and 10 normal regions of interest (ROIs). The Friedman test was used to test the significance of changes in ADC as a function of TE and of T2 as a function of b‐value. Results In normal prostate ROIs, the ADC at TE of 47 ms is significantly smaller than ADC at TE of 100 ms (P = 0.0003) and T2 at b‐value of 0 s/mm2 is significantly longer than T2 at b‐value of 1500 s/mm2 (P = 0.001). In cancer ROIs, average ADC and T2 values do not change as a function of TE and b‐value, respectively. However, in many cancer pixels, there are large decreases in the ADC as a function of TE and large increases in T2 as a function of b‐value. Cancers are more conspicuous in ADC maps at longer TEs. Conclusion Parameters derived from hybrid imaging that depend on coupled/associated values of ADC and T2 may improve the accuracy of MRI in diagnosing prostate cancer. J. Magn. Reson. Imaging 2014;39:781–788. © 2013 Wiley Periodicals, Inc.