Liver metastases on quantitative color mapping of the arterial enhancement fraction from multiphasic CT scans: Evaluation of the hemodynamic features and correlation with the chemotherapy response

Purpose: To demonstrate the hemodynamic features of liver metastases using quantitative color mapping of the arterial enhancement fraction (AEF) and to investigate the feasibility of using the AEF to predict the chemotherapy response. Materials and methods: Seventy-two patients with liver metastases (metastasis group) and 18 cancer-matched patients without liver metastases (non-metastasis group) were included. A quantitative AEF color map was created from multiphasic CT images using prototypic software. The AEF of tumor, tumor-adjacent parenchyma, and tumor-free parenchyma in the metastasis group; and the AEF of tumor-free parenchyma in the non-metastasis group were measured. In addition, in 28 patients with colorectal cancer for whom follow-up CT scans were available, the AEF on baseline CT scans was compared according to the initial response to chemotherapy in the response (n = 11) vs. the non-response group (n = 17). Result: In the metastasis group, the AEF of metastases (58.9 ± 15.8) was significantly higher than that of tumor-adjacent parenchyma (35.5 ± 15.4) (P < 0.0001). In addition, tumor-adjacent parenchyma had a higher AEF than tumor-free parenchyma (26.4 ± 7.5) (P < 0.0001). The AEF of tumor-free parenchyma in the metastasis group and that in the non-metastasis group (25.4 ± 3.7) did not show a significant difference. Of the patients with colorectal liver metastases, the response group demonstrated a significantly higher AEF of metastases (65.5 ± 9.6) than the non-response group (51.3 ± 13.2) (P < 0.01). Conclusion: Adding AEF mapping to multiphasic CT images can improve the demonstration of the hemodynamic features of liver metastases and may be helpful for predicting the tumor response in limited groups of patients with colorectal liver metastases.