Combination amide proton transfer imaging with diffusion-weighted imaging for differentiating tumor characteristics and assessing Ki-67 expression in soft tissue tumors.

Purpose: To investigate the utility of amide proton transfer (APT) imaging in conjunction with diffusion-weighted imaging (DWI) for distinguishing between benign and malignant soft tissue tumors (STTs), and to assess the correlation with Ki-67 expression.

Materials And Methods: A retrospective analysis was performed on 67 patients with soft tissue tumors. According to the pathological findings, the cohort was categorized into 39 cases of benign tumors and 28 cases of malignant tumors. ALL patients underwent APT imaging and DWI examinations, APT and Apparent diffusion coefficient (ADC) values were measured. Independent sample t-tests were used to compare the ADC and APT values between two groups. Receiver operating characteristic (ROC) curves were used to assess the sensitivity, specificity, and area under the curve (AUC) of APT, ADC, and the combination of ADC + APT in distinguishing benign and malignant tumors. The Delong test was employed to compare the diagnostic performance among these measures. Additionally, Spearman's correlation analysis was used to examine the relationship between APT, ADC and Ki-67 expression.

Results: The APT values of malignant groups were significantly higher than benign groups (3.32 ± 0.93 % vs. 1.87 ± 0.99 %; P < 0.01). The ADC values of malignant groups were significantly lower than benign groups (1.08 ± 0.55 × 10 mm/s vs. 1.67 ± 0.54 × 10 mm/s; P < 0.01). The ROC analysis showed that the AUC values of APT, ADC, and APT+ADC in distinguishing benign and malignant tumors were 0.855, 0.795, and 0.911 respectively. The Spearman's correlation analysis showed that APT and ADC values were significantly correlated with Ki-67 expression，and the correlation coefficients were 0.501 and -0.526, respectively.

Conclusions: The APT imaging and DWI can effectively differentiate between benign and malignant STTs. Combining these techniques enhances diagnostic efficiency. Furthermore, APT and ADC values show a significant correlation with tumor Ki-67 levels, which provides a robust basis for predicting STTs aggressiveness.