Abstract: Objective To explore the clinical value of magnetic resonance (MRI) diffusion imaging (DWI) combined with serum vascular endothelial growth factor (VEGF), cyclin A2 (CCNA2), and alpha-fetoprotein-L3 (AFP-L3) levels in the diagnosis of colorectal cancer (CRC) liver metastasis. Methods A total of 160 patients with colorectal cancer who were treated at the Imaging Department of Yulin First Hospital from March 2021 to April 2024 were selected as subjects, including 31 cases with liver metastasis in the metastasis group, and 129 cases without liver metastasis in the non-metastasis group. All patients underwent MRI+DWI examination, and serum VEGF, CCNA2, and AFP-L3 levels were measured. The imaging characteristics, apparent diffusion coefficient (ADC), and serum marker levels of these two groups of patients were compared. Results Liver metastases appear as iso- or slightly hyperintense signals on T₂-weighted imaging (T₂WI), with some areas showing uneven signals and margins that may be spiculated or lobulated. On T₁-weighted imaging (T₁WI), they exhibit iso- or slightly hypointense signals, while they show markedly hyperintense signals on diffusion-weighted imaging (DWI) and low signals on the ADC map. The ADC values in the metastatic group are significantly lower than those in the non-metastatic group [(0.87±0.11) × 10^-3 s/mm² vs. (1.02±0.13) × 10^-3 s/mm²], with a statistically significant difference (t=5.931, P＜0.05). Furthermore, the serum levels of VEGF, CCNA2, and AFP-L3 in the metastatic group are higher than those of the non-metastatic group [(313.47±49.29) pg/mL vs. (186.24±31.89) pg/mL; (2 430.84±471.75) pg/mL vs. (1 598.40±220.86) pg/mL; (83.37±40.70) μg/L vs. (9.47±3.79) μg/L, respectively], with all differences being statistically significant (t=13.699, 9.576, 10.099, all P＜0.05). In CRC patients with liver metastases, the mixed-type ADC values are lower than those of the desmoplastic and infiltrative types [(0.77±0.07) × 10^-3 s/mm² vs. (0.88±0.11) × 10^-3 s/mm² and (0.77±0.07) × 10^-3 s/mm² vs. (0.94±0.12) × 10^-3 s/mm²], with statistically significant differences (t=2.565, 3.780, both P＜0.05). However, there are no statistically significant differences in serum levels of VEGF, CCNA2, and AFP-L3 among the three subtypes (P＞0.05). ROC curve analysis results showed that the sensitivity, specificity, accuracy, and Kappa value of MRI diagnosis were 74.19%, 81.40%, 80.00%, and 0.465, respectively. The sensitivity, specificity, accuracy, and Kappa value of MRI combined with DWI were 77.42%, 89.92%, 87.50%, and 0.627, respectively. When MRI, DWI, and serum VEGF, CCNA2, and AFP-L3 were used together, the sensitivity, specificity, accuracy, and Kappa value increased to 96.77%, 99.22%, 98.75%, and 0.960, respectively, showing very high consistency and reliability. Conclusion This study demonstrates that the combined diagnostic method of MRI with DWI and serum levels of VEGF, CCNA2, and AFP-L3 exhibits excellent diagnostic performance in detecting colorectal cancer liver metastasis. Compared to the use of MRI or DWI alone, the combined approach showing higher sensitivity and specificity.

Key words: MR diffusion imaging, Serum VEGF, CCNA2, AFP-L3, Colorectal cancer, Liver metastasis