To explore the qualitative diagnostic value of superb microvascular imaging (SMI) combined with contrast-enhanced ultrasound (CEUS) for liver space occupying lesions.

The clinical data of 115 patients with liver space occupying lesions who were admitted to our hospital from January 2023 to December 2025 were retrospectively collected. All patients underwent SMI and CEUS examinations, with surgical or puncture pathology results as the gold standard. The qualitative diagnostic results of SMI and CEUS alone and in combination for liver mass lesions were calculated, including the sensitivity, specificity, accuracy, positive predictive value, negative predictive value, and consistency K value. The diagnostic accuracy of SMI and CEUS alone and in combination for different subgroups of liver mass lesions was analyzed. Based on the conventional ultrasound characteristics of different liver occupying lesions, a regression model was constructed and validated using Bootstrap self sampling, Hosmer-Lemeshow goodness of fit test, and decision curve.

In 115 patients with liver mass lesions, 48 were diagnosed with malignant lesions and 67 with benign lesions based on surgical or puncture pathology results. The pathological results of surgery or puncture were the gold standard, and the detection rates of SMI, CEUS alone, and in combination for malignant liver lesions were 75.00%, 70.83%, and 95.83%, respectively. The sensitivity, accuracy, and negative predictive value of SMI combined with CEUS were higher than those of SMI and CEUS alone, and the K value was the highest, at 0.757, with statistical significance differences (P<0.05). In the subgroup of lesions ≤ 3 cm, the accuracy of SMI and CEUS diagnosis alone was lower than that of combined diagnosis; in the subgroup of hepatocellular carcinoma, the accuracy of CEUS diagnosis alone was lower than that of combined diagnosis, all with statistical significant differences (P<0.05). The proportion of internal high echo, posterior echo attenuation, irregular morphology, and unclear boundaries in the malignant group was higher than that in the benign group (P<0.05). The results of Logistic regression analysis showed that SMI combined with CEUS diagnosis, internal echo, posterior echo, morphology, and boundary were all influencing factors of malignant liver lesions (P<0.05). Based on this, a regression model was constructed, and the internal validation results showed that the consistency index of the model was 0.955 (95% CI: 0.940~0.962). The fit between the internal calibration curve and the ideal curve was well reflected. The Hosmer-Lemeshow goodness of fit test results showed that the predicted outcome of the model was basically consistent with the actual situation (χ²=4.162, P=0.526). According to the decision curve evaluation, the model had a high net return rate within the threshold probability range of 0.01~0.09 and 0.33~0.93, with a maximum net return rate of 0.414.

SMI combined with CEUS has high qualitative diagnostic value for liver space occupying lesions and can assist clinical decision-making.