Diffusion kurtosis imaging and intravoxel incoherent motion imaging parameters in breast lesions: Effect of radiologists’ experience and region-of-interest selection

Abstract

PurposeTo investigate the influence of ROI placement methods and radiologists’ experience on diffusion kurtosis imaging (DKI) and intravoxel incoherent motion (IVIM) parameters’ diagnostic performance in differentiating benign and malignant lesions based on the mass and non-mass enhancement (NME). MethodsWe evaluated 138 lesions in 131 patients retrospectively. The IVIM and DKI parameter values were measured by three radiologists with different experiences independently using two different ROI placement methods. IVIM parameters include diffusion coefficient (ADCstand), true diffusion coefficient (ADCslow), pseudo-diffusion coefficient (ADCfast) and perfusion fraction (f). DKI parameters include mean diffusivity (MD) and mean kurtosis (MK). Each radiologist measured the lesions twice with a 3-month interval. We utilized intra-class correlation (ICC) to determine the inter- and intra-reader agreement for mass and NME, respectively. ROC analysis compared the diagnostic performance of parameters between different radiologists, ROI methods, and between mass and NME. ResultsIn mass lesions, inter- and intra-observer agreement were perfect for all parameters (ICC: 0.800–989). In NME, the inter-observer agreement was substantial to perfect for all parameters(ICC: 0.703–877), the intra-observer agreement of the senior and intermediate radiologists was substantial to perfect(ICC: 0.748–931) and the intra-observer agreement of the junior radiologist was moderate to substantial(ICC: 0.569–784). The diagnostic performance of ADCslow (Z = 2.209, P = 0.023), MD (mean diffusivity) (Z = 2.887, P = 0.004), and MK (mean kurtosis) (Z = 2.080, P = 0.038) in the small ROI measured by the senior radiologist was better than that of the junior radiologist for NME. The diagnostic performance of ADCslow in the large ROI measured by the senior radiologist (Z = 2.281, P = 0.023) and intermediate radiologist (Z = 2.867, P = 0.0041) was better than the junior radiologist for mass lesions. The diagnostic performance of ADCslow, ADCstand, MD, and MK did not show a significant difference between the two ROI placement methods (P > 0.05). ConclusionThe observers’ experience can influence the ROI selection and the diagnostic performance of ADCslow, ADCstand, MD, and MK measured using different methods show equal diagnostic performance.