Comparison of Fitting Methods and b-Value Sampling Strategies for Intravoxel Incoherent Motion in Breast Cancer

Purpose: To compare fitting methods and sampling strategies, including the implementation of an optimized b-value selection for improved estimation of intravoxel incoherent motion (IVIM) parameters in breast cancer. Methods: Fourteen patients (age, 48.4 +/- 14.27 years) with cancerous lesions underwent 3 Tesla breast MRI examination for a HIPAA-compliant, institutional review board approved diffusion MR study. IVIM biomarkers were calculated using free versus segmented fitting for conventional or optimized (repetitions of key b-values) b-value selection. Monte Carlo simulations were performed over a range of IVIM parameters to evaluate methods of analysis. Relative bias values, relative error, and coefficients of variation (CV) were obtained for assessment of methods. Statistical paired t-tests were used for comparison of experimental mean values and errors from each fitting and sampling method. Results: Comparison of the different analysis/sampling methods in simulations and experiments showed that the segmented analysis and the optimized method have higher precision and accuracy, in general, compared with free fitting of conventional sampling when considering all parameters. Regarding relative bias, IVIM parameters f(p) and D-t differed significantly between segmented and free fitting methods. Conclusion: IVIM analysis may improve using optimized selection and segmented analysis, potentially enabling better differentiation of breast cancer subtypes and monitoring of treatment. (C) 2014 Wiley Periodicals, Inc.