Xing Meng1, Ailian Liu2, and Shifeng Tian2
1Dalian Women and Children’s Medical Group, Dalian, China, 2the First Affiliated Hospital of Dalian Medical University, Dalian, China
Synopsis
Keywords: Cancer, Uterus
APTw and mDixon-Quant imaging were evaluated in this study for discrimination of the differention degree of CSC by histopathology. The APTw and R2* values of the poorly differentiated group were significantly higher than those of the well/moderately differentiated group. And the combination of APTw and R2* values showed a high diagnostic efficacy in discrimination of CSC with different differention degrees.
INTRODUCTION
Cervical squamous carcinoma (CSC) is a common pathologic type of cervical tumors. The degree of tumor differentiation is a prognostic factor of CSC, especially during the early stages of the disease. modified Dixon quantification (mDixon-Quant) is a water-fat separation technology that enables semutaneous mapping of proton density fat fraction and transverse relaxation rate (R2*=1/T2*) [1], thus reflecting the fat contents and iron deposition in tissues. Amide proton transfer weighted (APTw) imaging is a subset of Chemical Exchange Saturation Transfer technologies, which use off-resonance saturation pulses to detect free protein and polypeptide molecules in cell cytoplasm without using an exogenous contrast agent [2]. The purpose of this study was to investigate value of APTw imaging combined with mDixon-Quant in determining the degree of differentiation of CSC against histopathologic.METHODS
Magnetic resonance imaging (MRI) data (T2WI, mDixon-Quant, and APTw imaging) were collected from 52 CSC patients with information about the degree of differentiation on histopathology. According to histopathologic results, patients were divided into the poorly differentiated group (37 cases) and the well/moderately differentiated group (15 cases). The APTw value by APTw imaging and the fat fraction (FF) and transverse relaxation rate (R2*) values by mDixon-Quant were independently measured by two radiologists. Intra-class correlation coefficients (ICCs) were used to test the consistency of APT, FF, and R2* values measured by the two observers. The Mann-Whitney U test was used to analyze the difference in each parameter between the two groups. Logistic regression analysis was used to assess the association between the degree of differentiation on histopathology and imaging parameters by APTw and mDixon Quant. The ROC curve was used to evaluate the diagnostic efficacy of various parameters and their combinations in distinguishing the degree of CSC differentiation on histopathology. The DeLong test was used to access the differences in the area under the ROC curve (AUC). The Pearson correlation coefficient was used to evaluate the correlation between APTw and mDixon-Quant imaging parameters.RESULTS
Measurements by the two observers were in good agreement (ICC > 0.75). The APTw means were 2.95 ± 0.78% and 2.05 (1.85, 2.65)% in the poorly and well/moderately differentiated groups, respectively. The R2* values were 26.62 (21.99, 33.31) /s and 22.93 ± 6.09 /s in the poorly and well/moderately differentiated groups, respectively (P < 0.05). The AUCs of APTw, R2*, and their combination were 0.762, 0.686, and 0.843, respectively, with sensitivities of 81.1%, 51.4%, and 67.6%, and specificities of 73.3%, 80%, and 93.3%, respectively. The Delong test suggested statistical significance between R2* and the combination of APTw and R2*. R2* values showed significant correlations with APTw values in the poorly differentiated group (P < 0.05).DISCUSSION AND CONCLUSIONS
APTw combined with mDixon-Quant can be used to efficiently distinguish the differention degrees of CSC diagnosed on histopathology. In this study, the R2* values of poorly differentiated tumors were significantly higher than those of the well/moderately differentiated tumors. As we know, R2* is sensitive to local magnetic field inhomogeneity [3]. When the paramagnetic material of blood metabolites including deoxyhemoglobin and hemosiderin produce local inhomogeneous magnetic field, the R2* value increases [4]. The results of this study showed that the APTw values of poorly differentiated CSC were significantly higher than those of well/moderately differentiated CSC. Poorly differentiated CSC cells have more active proliferation and higher cell densities than well/moderately differentiated CSC cells, allowing additional free proteins and polypeptides to be synthesized. APTw reflects free protein and polypeptide concentrations in tissues, which are affected by the heterogeneity and composition of tumors [5]. Combination of APTw and R2* image analysis can provide information about cell proliferation by measuring the changes in protein concentrations and iron content in tumor microenvironments, and thus showed improved diagnosis between poorly and well/moderately CSC.Acknowledgements
No acknowledgement.References
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