High correlation between Ki-67 expression and a novel perfusion MRI biomarker diffusion-derived vessel density (DDVD) in endometrial carcinoma.

OBJECTIVE

This study aimed to investigate the feasibility of diffusion-derived vessel density (DDVD) in characterizing tumor microvasculature in endometrial carcinoma (EC), and to explore the correlations with Ki-67 proliferation status and histological type based on DDVD values.

METHODS

There were in total 81 EC patients. There were 64 cases of non-aggressive histological type, and 17 cases of aggressive histological type. Ki-67 labeling index was low (<50 %) in 35 cases and high (≥50 %) in 46 cases. DDVD is calculated according to: DDVD = S/ROI - S/ROI, where S and S refer to the tissue signal when b is 0 or 20 s/mm. Intraclass correlation coefficient (ICC); two-tailed independent samples t-test and Mann-Whitney U test, and Receiver operating characteristic area under the curve (AUC) were applied for statistical analysis.

RESULTS

Endometrial carcinoma showed lower DDVD values (34.9 ± 21.2, au/pixel) compared with myometrium (65.3 ± 37.4, P < 0.001). Tumors with Ki-67 high-proliferation or aggressive histological type had higher DDVD values than those with Ki-67 low-proliferation (44.17 (median) vs. 16.08, P < 0.001]] or non-aggressive histological type (47.92 vs. 30.77, P = 0.002). DDVD ROC curve analysis shows AUC of 0.842 for distinguishing between Ki-67 low- and high-expression, and AUC of 0.771 for distinguishing between non-aggressive and aggressive histological types. DDVD > 32.9 and DDVD > 50.1 provided a specificity of 85 % for identifying Ki67 high expression (sensitivity 78.3 %) and histological aggressive type (sensitivity 47.1 %), respectively.

CONCLUSION

DDVD can act as an imaging marker reflecting Ki-67 proliferation and histological aggressiveness of EC, thus helping pretreatment risk assessment in EC.