Abstract
The impact of the contrast medium on the radiomic textural features (TF) extracted from the CT scan is unclear. We investigated the modification of TFs of colorectal liver metastases (CLM), peritumoral tissue, and liver parenchyma. One hundred and sixty-two patients with 409 CLMs undergoing resection (2017–2020) into a single institution were considered. We analyzed the following volumes of interest (VOIs): The CLM (Tumor-VOI); a 5-mm parenchyma rim around the CLM (Margin-VOI); and a 2-mL sample of parenchyma distant from CLM (Liver-VOI). Forty-five TFs were extracted from each VOI (LIFEx®®). Contrast enhancement affected most TFs of the Tumor-VOI (71%) and Margin-VOI (62%), and part of those of the Liver-VOI (44%, p = 0.010). After contrast administration, entropy increased and energy decreased in the Tumor-VOI (0.93 ± 0.10 vs. 0.85 ± 0.14 in pre-contrast; 0.14 ± 0.03 vs. 0.18 ± 0.04, p < 0.001) and Margin-VOI (0.89 ± 0.11 vs. 0.85 ± 0.12; 0.16 ± 0.04 vs. 0.18 ± 0.04, p < 0.001), while remaining stable in the Liver-VOI. Comparing the VOIs, pre-contrast Tumor and Margin-VOI had similar entropy and energy (0.85/0.18 for both), while Liver-VOI had lower values (0.76/0.21, p < 0.001). In the portal phase, a gradient was observed (entropy: Tumor > Margin > Liver; energy: Tumor < Margin < Liver, p < 0.001). Contrast enhancement affected TFs of CLM, while it did not modify entropy and energy of parenchyma. TFs of the peritumoral tissue had modifications similar to the Tumor-VOI despite its radiological aspect being equal to non-tumoral parenchyma.
Highlights
Lesions with a diameter < 10 mm were excluded from the study for the following reasons: They could not guarantee a sufficient number of voxels for the analysis; second-order radiomic features could be not reliable and/or informative in small lesions; and a 5-mm thick rim surrounding the metastasis was analyzed to evaluate the peritumoral tissue and it is probably too large for millimetric metastases
The present study demonstrated that contrast enhancement affects most textural features of colorectal liver metastases, while it does not modify entropy and energy of liver parenchyma
We collected a large cohort of patients and compared the pre-contrast and the portal phase of computed tomography (CT) scan of the tumor, the liver parenchyma remote from colorectal liver metastases (CLM), and the peritumoral tissue
Summary
Aggressive systemic therapies are administered, aiming at transforming cancer into a chronic disease [2]. Imaging plays a pivotal role in clinical decisions [6,7], but a precision medicine approach should consider tumor biology rather than just morphology to plan optimal management of patients. This is an unmet need in current oncological practice since available biomarkers do not predict survival consistently or can be identified on the surgical specimen only a posteriori [7,8,9,10]
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