Introduction

To investigate the value of enhanced T2* weighted angiography (ESWAN) sequence automatically quantitative intratumoral susceptibility signal (ITSS) in predicting the expression of Ki-67 proliferative antigen in ovarian epithelial derived malignant tumors.

Methods

The data of 20 patients with ovarian cancer confirmed by pathology who underwent 1.5TMRI scan (including ESWAN sequence) in the First Affiliated Hospital of Dalian Medical University from January 2015 to November 2020 were retrospectively analyzed. Ki-67 expression was divided into high expression group (n=9, Ki-67 > 50) and low expression group (n=11, Ki67≤50). AnatomySketh（AS） software was used by two observers respectively to delineate lesions, and the maximum cross-section ratio of quantitative ITSS lesions was automatically obtained. The consistency of the two observers' parameters and the difference between the two groups were compared, and the differential diagnostic efficacy of the different parameters was assessed using receiver operating characteristic (ROC)

Results

There was a good consistency between the two observers (ICC > 0.75). The ITSS ratio of the high expression group was 0.1575 (0.1021,0.2917), which was higher than that of the low expression group 0.661 (0.378,0.1388), and the difference was statistically significant (Z=-2.165,P＜0.05), The area under ROC curve of the highly expressed ITSS group was 0.788, the sensitivity was 88.9%, and the specificity was 36.4%.

Discussion

The high expression of Ki-67 in ovarian cancer is significantly correlated with the lower survival rate, but its expression is only obtained after the postoperative immunohistochemical staining analysis. If the expression of Ki-67 can be obtained before surgery, it can help the clinical indirectly judge the cell proliferation of ovarian cancer and provide reference for the formulation of treatment plans. It can be used as one of the biomarkers for prognosis of ovarian cancer patients.
ITSS is a low signal region with continuous dots or thin lines inside the tumor on the phase diagram, and the main source is micro-bleeding and neovascularization inside the lesion. The growth, invasion and metastasis of malignant tumors depend on neovascularization, and the level of angiogenesis is an important indicator to evaluate the aggressiveness of tumors. ITSS is consistent with the density and size of microvessels in the histological samples, which is a non-invasive imaging marker that visually displays the proliferation of blood vessels inside tumors.
In this study, automatic extraction and quantitative ITSS was used for the first time to predict he Expression of Ki-67 in of the ovarian cancer, overcoming the shortcomings of semi-quantitative method that could not reflect local differences in lesions and was difficult to compare. Moreover, because the blood vessels of malignant tumors are irregular, clustered and not easy to identify, manual ITSS counting is time-consuming, laborious and subjective, so the automatic extraction and quantification of ITSS using AS software is more suitable for clinical work.
The automatic quantitative ITSS method proposed in this study has good efficacy in identifying the expression of Ki-67 in ovarian cancer, and the agreement between two observers is good, which confirms the stability of the method. Automatic quantitative ITSS can quantitatively evaluate the expression of Ki-67 in ovarian cancer. With the increase of Ki-67 expression, the number of blood vessels in the tumor increases. The reason may be that with the increase of Ki-67 expression, the malignancy of tumor cells increases, and the number of microvessels supplying tumor nutrients also increases, so the number of blood vessels in the tumor increases correspondingly.
Automatic quantitative ITSS can be used as a noninvasive method to evaluate the proliferation of ovarian cancer cells, which has certain clinical application value

Conclusion

The automatic quantitative ITSS can reflect the proliferation degree of malignant tumor cells derived from ovarian epithelial edema, and can improve the diagnostic efficiency.

Acknowledgements

No acknowledgement found.

References

No reference found.