On a fractional order calculus model in diffusion weighted breast imaging to differentiate between malignant and benign breast lesions detected on X-ray screening mammography

Objective To evaluate a fractional order calculus (FROC) model in diffusion weighted imaging to differentiate between malignant and benign breast lesions in breast cancer screening work-up using recently introduced parameters (a FROC, DFROC and ae FROC). Materials and methods This retrospective analysis within a prospective IRB-approved study included 51 participants (mean 58.4 years) after written informed consent. All patients had suspicious screening mammograms and indication for biopsy. Prior to biopsy, full diagnostic contrastenhanced MRI examination was acquired including diffusion-weighted-imaging (DWI, b = 0,100,750,1500 s/mm(2)). Conventional apparent diffusion coefficient D-app and FROC parameters (beta(FROC), D-FROC and mu(FROC)) as suggested further indicators of diffusivity components were measured in benign and malignant lesions. Receiver operating characteristics (ROC) were calculated to evaluate the diagnostic performance of the parameters. Results 29/51 patients histopathologically revealed malignant lesions. The analysis revealed an AUC for Dapp of 0.89 (95% CI 0.80 - 0.98). For FROC derived parameters, AUC was 0.75 (0.60 -0.89) for DFROC, 0.59 (0.43 - 0.75) for alpha FROC and 0.59 (0.42 - 0.77) for mu(FROC). Comparison of the AUC curves revealed a significantly higher AUC of Dapp compared to the FROC parameters D-FROC (p = 0.009), beta(FROC) (p = 0.003) and mu(FROC) (p = 0.001). Conclusion In contrast to recent description in brain tumors, the apparent diffusion coefficient D-app showed a significantly higher AUC than the recently proposed FROC parameters beta(FROC), D-FROC and mu(FROC) for differentiating between malignant and benign breast lesions. This might be related to the intrinsic high heterogeneity within breast tissue or to the lower maximal b-value used in our study.