Computed diffusion-weighted imaging using 3-T magnetic resonance imaging for prostate cancer diagnosis

Objective: To assess the efficacy of computed diffusion-weighted images (cDWIs) of b = 2000 s/mm² (cDWI₂₀₀₀) generated from DWIs of b = 0 and 1000 for prostate cancer (PCa) diagnosis in comparison with that of measured original DWIs of b = 1000 (mDWI₁₀₀₀) and b = 2000(mDWI ₂₀₀₀) using 3-T MRI. Methods: Eighty patients who underwent a preoperative MRI examination, including T2WI and DWI (b = 0, 1000, 2000 s/mm²), were enrolled in this study. Four combinations of images, protocol A (T2WI alone), B (T2WI + mDWI₁₀₀₀), C (T2WI + mDWI ₂₀₀₀) and D (T2WI + cDWI₂₀₀₀), were assessed for their diagnostic capability. Areas under the receiver operating characteristic curve (Az) and diagnostic performance were evaluated, as well as contrast ratios (CR) between cancerous and non-cancerous lesions for each DWI. Results: The highest CR was obtained with cDWI₂₀₀₀ (0.29 ± 0.16). Sensitivity, specificity, accuracy, and Az of the protocols were: A: 66.3 %, 59.4 %, 63.0 %, 0.67; B: 82.6 %, 62.0 %, 72.5 %, 0.80; C: 84.1 %, 66.5 %, 75.5 %, 0.86; D: 83.2 %, 70.0 %, 76.6 %, and 0.84, respectively The specificities and accuracies of protocol C and D were significantly higher than those of protocol B (P < 0.05). Conclusion: cDWI₂₀₀₀ appears to be more effective than mDWI₁₀₀₀, and at least as effective as mDWI₂₀₀₀ for PCa diagnosis. Key Points: • Computed diffusion-weighted MRI with over b1000s/mm ² is useful for prostate cancer detection. • Computed DWI produces any b-value images with two different b-value images. • DWI with computed b2000s/mm ² is as valuable as DWI with measured b2000 s/mm ² .