Synopsis

Keywords: Digestive, Cancer

Dynamic contrast-enhanced (DCE) MRI incorporates arterial input function and pharmacokinetic models to assess tissue perfusion, vasculature, capillary permeability, and interstitial space volume. It can be used to assess tumor vascularization, which can help determine tumor aggressiveness and the degree of angiogenesis and monitor therapy. However, the relationship between pathological characteristics of rectal cancer and the quantitative analysis of DCE remains unclear.

Purpose

In this prospective study, we investigated the relationships between various tissue components (percentage of angiogenesis, nuclei of epithelial cells, nuclei of cancer cells, collagen fibers and mesenchymal cells) in rectal cancer and in vivo DCE MR imaging parameters.

Patients and Methods

Twenty-four patients (median age, 65 years; age range, 35-82 years) provide informed consent for this study. Before undergoing total mesorectal excision, patients were examined with DCE-MRI. Quantitative parameters were calculated based on a modified Tofts model. Whole-mount immunohistochemistry and Masson staining sections were generated and digitized at histological resolution. The percentage area of tissue components was measured using image segmentation. Pearson correlation analysis was used to evaluate the correlations of pathology parameters with DCE MRI parameters.

Results

On the WHO grading scale, significant differences were observed in Ktrans (F=9.890, P=0.001), MTT (F=9.890, P=0.038), CDX-2 (F=4.935, P=0.018) and Ki-67 (F=4.131, P=0.031) between G1, G2, and G3. The ECV showed significant differences in extramural venous invasion (t=-2.113, P=0.046). Ktrans showed a strong positive correlation with CD34 (r=0.708, P=0.000) and a moderate positive correlation with vimentin (r=0.450, P=0.027). Ve showed a moderate positive correlation with Masson’s (r=0.548, P=0.006) and vimentin (r=0.417, P=0.043). A moderate negative correlation was observed between Ve and CDX-2 (r=-0.441, P=0.031). Kep showed a strong positive correlation with CD34 expression (r=0.622, P=0.001). The ECV showed a moderate negative correlation with CDX-2 (r=-0.472, P=0.020) and a moderate positive correlation with collagen fibers (r=0.558, P=0.005).

Conclusions

Dynamic contrast-enhanced MRI-derived parameters measured in rectal cancer were significantly related to the proportion of histological components. This may serve as an optimal imaging biomarker for the identification of tumor tissue components.

Acknowledgements

Conflict of Interest declaration The authors declare that they have NO affiliations with or involvement in any organization or entity with any financial interest in the subject matter or materials discussed in this manuscript.