Monoexponential, biexponential, stretched exponential and diffusion kurtosis models of diffusion-weighted imaging: A quantitative differentiation of solitary pulmonary lesion

Abstract

Abstract Objective Quantitative comparison of monoexponential, biexponential, and stretched exponential diffusion-weighted MR imaging and diffusion kurtosis MR imaging in differential diagnosis of benign and malignant solitary pulmonary lesions (SPL). Method Forty-four SPL subjects were selected according to the inclusion criteria, and multi b-value DWI data were collected. Monoexponential DWI and DKI model were fitted using least square method. Levenberg-Marquardt nonlinear fitting biexponential and stretched exponential DWI. Region of interests (ROIs) were described manually. Parameters between benign and malignant SPLs were compared using independent sample t test or the Mann-Whitney U test. Correlation between all parameters were evaluated by using Spearman correlation. Result ADC, ADCslow, α, DDC and Dapp values were significantly lower in malignant SPL than in benign SPL (P < 0.001). Kapp was significantly higher in malignant SPL than in benign SPL (P < 0.001). No differences were found between the parameters ADCfast and f which reflect perfusion. Among all subjects, ADCslow was significantly lower than ADC (P < 0.05), while DDC and Dapp were significantly higher than ADC (P < 0.05). When observing the working characteristic curves of subjects for distinguishing benign and malignant SPL, the AUC values of ADC, ADCslow, DDC, Dapp, and Kapp were 0.904, 0.815, 0.942, 0.93, and 0.815, respectively. The DDC value has the maximum area under the curve. DeLong analysis showed no statistically significant difference in the area under ADC, DDC, and Dapp curves. There were strong correlations among ADC, ADCslow, ADCfast, f, α，DDC, Dapp, and Kapp (P<0.001). Conclusion Compared with traditional diffusion parameters, the DWI extended model does not showed significant advantages, but α And Kapp could provide additional information for the differentiation of benign and malignant SPL, which may help improve treatment strategies and prognosis.