The results of this study indicate that PLT and Vs are independent predictive factors for significant hepatic fibrosis in patients with AILDs. Among the six machine learning algorithms used in the study, the LR algorithm demonstrated good performance in predicting significant hepatic fibrosis. PLT, Vs, and LR algorithm-based multimodal radiomics features were combined in this study to construct a non-invasive nomogram prediction model, which aimed at predicting significant hepatic fibrosis in patients with AILDs, and this nomogram model exhibited superior diagnostic efficacy in both the training and validation cohorts.
In this study, PLT was an independent predictor of significant hepatic fibrosis, this result is consistent with those of the above-mentioned studies, which may explain that there is a correlation between hypersplenism and thrombocytopenia in the process of hepatic fibrosis [24,25]. Vs can also be used as an independent predictor of significant hepatic fibrosis, and we can indirectly assess tissue hardness by measuring the speed at which the shear waves travel through tissue, thus helping to assess the stage of hepatic fibrosis [26]. In a study of 114 patients with AILDs, Zeng et al. used 2D-SWE to predict significant hepatic fibrosis, with an AUC of 0.85 [27]. In this study, Vs was used to assess the significant hepatic fibrosis, with an AUC of 0.712 in the training cohort and 0.818 in the validation cohort, respectively. Considering that different ultrasonic instruments adopt different elasticity measurement methods and pathological scoring criteria, there may be a certain degree of variability. In addition, the patients with AILDs often have active hepatic inflammation, elevated aminotransferase level, and cholestasis, which often lead to bias in LSM value [12].
Therefore, we introduced radiomics and machine learning to enhance the diagnostic efficacy of the model. As a computer-aided quantitative analysis method, the radiomics can extract high-dimensional image data from the ROI using machine learning algorithms and convert them into radiomics features with pathological relevance [28,29]. At present, the "radiomics + machine learning" analytical approach has become a mainstream solution for medical image analysis [22]. The study by Xu et al. demonstrates that "radiomics + machine learning" can learn from image data, thus reducing interference from subjective factors and ensuring the objectivity and reliability of prediction results [30]. A radiomics model constructed by Zhao et al. based on the SVM algorithm exhibited an excellent ability to discriminate between mild and severe hepatic fibrosis induced by Schistosoma japonicum infection [19]. In this study, six machine learning algorithms (LR, Boost, SVM, RF, ET, and Light) were used for modeling and analysis of the extracted radiomics features. Among them, the LR algorithm had the best overall performance in the validation cohort (AUC = 0.838). Therefore, LR was selected as the core algorithm for the single-modal models. The advantage of this algorithm is that it combines an L2 normalization constraint with maximum likelihood function and adopts stochastic gradient descent optimization, which can effectively balance between the prediction accuracy of binary classification problems and the model complexity [24].
Some studies have confirmed [15,19] that the radiomics has a higher value in the diagnosis and staging of diffuse liver diseases, but the performance of the method based on single-modal US images in hepatic fibrosis staging is limited. At present, the multimodal ultrasound radiomics model that combine gray-scale ultrasonography with elastography (sound touch elastography, STE) can significantly increase the sensitivity and specificity of hepatic fibrosis assessment. For example, Ge et al. utilized a combination of STE and 2D-US to enhance the diagnostic performance for renal tubular interstitial fibrosis in chronic kidney disease [31]. Therefore, we used a multimodal radiomics model integrating both 2D-US and SWE features to reduce the impact of inflammation on the model.
The AUC of this multimodal nomogram model was 0.860 in the training cohort and 0.912 in validation cohorts, respectively, which was significantly better than those of single-modal model, FIB-4 and APRI models (Delong’s test, P < 0.05). This result suggests that this multimodal radiomics model can enhance classification performance through complementary information. This is consistent with the findings of the studies by Xue et al. A multimodal approach shows better performance compared with a single-modal approach, indicating the multimodal approach can carry more diagnostic information[32].The superiority of this combined nomogram model stems from the integration of multidimensional data: on one hand, the quantitative information on liver stiffness provided by SWE was included; on the other hand, the independent predictors such as PLT and Vs selected in the multifactor analysis were integrated, thereby the informational limitation of single imaging or serological index was overcome, and the diagnostic efficacy for significant hepatic fibrosis was enhanced.
Furthermore, SHAP-based interpretation of the 2D_SWE model identified original_
shape_Maximum2DDiameterRow, wavelet_LHH_gldm_SmallDependenceHighGray
LevelEmphasis and wavelet_HHH_gldm_DependenceVariance as the top three features exerting the strongest positive effects on model predictions. Specifically: The elevated SHAP value of original_shape_Maximum2DDiameterRow implies a potential association between macroscopic morphological irregularity and advancing fibrosis. The prominent contributions of wavelet-based features (wavelet_LHH_gldm_Small
DependenceHighGrayLevelEmphasis, wavelet_HHH_gldm_DependenceVariance) highlight the diagnostic relevance of microstructural heterogeneity in stratifying fibrosis stages. This finding not only corroborates the biological rationale underlying radiomics-based fibrosis evaluation but also offers clinically interpretable, quantifiable insights into the model’s decision-making process.
There are some limitations in this study. First, the enrolled patients included patients with various AILDs. There was an unbalanced sample size among patients with different AILDs, which may affect the diagnostic accuracy of the combined prediction model constructed in this study, which should be validated in each AILD separately in the future studies. Second, this study only included 147 patients with AILDs, and the patients with S0-1 hepatic fibrosis accounted for a relatively small proportion. The sample size needs to be expanded in future studies to reduce overfitting during model construction. Third, this was a single-center study, and only one type of ultrasound diagnostic device was used. In the future, multi-center studies and different ultrasonic devices will be needed for experiments to construct more generalizable combined models. Fourth, this study only included the image data of 2D-US and SWE, and future studies can incorporate contrast-enhanced ultrasound images and splenic images for constructing more multimodal models. Finally, because AILDs had a prolonged course, the follow-up time for patients with AILDs was insufficient in this study, and the follow-up time should be extended in the future studies to explore the effect of the combined prediction model on the prognosis of patients with AILDs.