Measurement of Hepatic Metastases from Breast Cancer by Dual Energy CT: Differences in Tumor Measurements between Non-Contrast, Virtual Non-Contrast, and Portal Venous Phase

To assess hepatic metastases between traditional non-contrast phase (NCP), portal venous phase (PVP), and virtual non-contrast phase (VNC) reconstructed from Dual Energy Computed Tomography (DECT) performed in subjects with breast cancer. Methods: Hepatic metastatic lesions from breast cancer in consecutive, pre and post-contrast DECT examinations were retrospectively assessed by 2 experienced readers. Lesions were measured in single longest dimension (SLD) for each phase (NCP, PVP, VNC) and the mean difference was assessed by Kruskal-Wallis test. One reader also assessed contrast to noise ratio (CNR) of the lesions compared to the liver for each phase with difference also assessed by Kruskal-Wallis test. Results: 87 hepatic metastatic lesions were assessed in 23 eligible subjects. SLD was greater for NCP (mean 2.14 cm) compared to PVP (mean 1.94 cm)(p<.001). The difference between VNC and PVP was also significant (2.09 cm vs. 1.94 cm)(p<.001), however, the difference between NCP and VNC was not significant (p=.25). Mean lesion CNR was 3.19 on PVP, 2.65 on VNC, and 1.21 for NCP, all of which were significantly different. Conclusions: VNC may be an adequate substitute to NCP in accurately assessing and measuring hepatic metastases from breast cancer.