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Introduction: In order to improve the efficacy of intravoxel incoherent motion (IVIM) parameters in characterising specific tissues, a new concept is introduced: the perfusion-diffusion ratio (PDR), which expresses the relationship between the signal S ( b ) decline rate as a result of IVIM and the rate of signal S ( b ) decline due to diffusion. The aim of this study was to investigate this novel approach in the differentiation of solid primary liver lesions. Material and Methods . Eighty-three patients referred for liver MRI between August 2017 and January 2020 with a suspected liver tumour were prospectively examined with the standard liver MRI protocol extended by DWI-IVIM sequence. Patients with no liver lesions, haemangiomas, or metastases were excluded. The final study population consisted of 34 patients with primary solid liver masses, 9 with FNH, 4 with regenerative nodules, 10 with HCC, and 11 with CCC. The PDR coefficient was introduced, defined as the ratio of the rate of signal S ( b ) decrease due to the IVIM effect to the rate of signal S ( b ) decrease due to the diffusion process, for b = 0., Results: No significant differences were found between benign and malignant lesions in the case of IVIM parameters ( f , D , or D ∗ ) and ADC. Significant differences were observed only for PDR, with lower values for malignant lesions ( p = 0.03). The ROC analysis yielded an AUC value for PDR equal to 0.74, with a cut-off value of 5.06, sensitivity of 81%, specificity of 77%, and accuracy of 79%., Conclusion: PDR proved to be more effective than IVIM parameters and ADC in the differentiation of solid benign and malignant primary liver lesions., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2022 Joanna Podgórska et al.)