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Value of the heterogeneity of intravoxel diffusion (α) in diagnosing stage IA and IB of endometrial carcinoma1radiology, the first Affiliated Hospital of Dalian Medical University, dalian, China, 2the First Affiliated Hospital of Dalian Medical University, dalian, China, 3GE Healthcare, Beijing, China
Synopsis
Preoperative information about depth of myometrial invasion is essential in tailoring the surgical approach for endometrial carcinoma (EC) patients in stage I. To evaluate the value of stretched-exponential models of intravoxel incoherent motion (IVIM) in the differential diagnosis between stage IA and IB of endometrial carcinoma. In this work, we found it is feasible that IVIM sequence derived α value can be applied in the differential diagnosis between stage IA and IB of endometrial carcinoma, which can provide detailed information for clinical treatment.
Introduction
Endometrial carcinoma (EC) is one of the common gynecologic malignancies. Tumors confined to the endometrium and those invading the superficial myometrium are designated as stage IA, and tumors invading the deep myometrium are designated as stage IB [1]. Depth of myometrial invasion is the most important morphologic prognostic factor [1]. The incidence of lymph node metastases increases from 3% with superficial myometrial invasion to 46% with deep myometrial invasion. Preoperative information about the depth of myometrial invasion is therefore essential in tailoring the surgical approach for patients in stage IA or IB [2]. To offer new ideas for preoperative staging of endometrial carcinoma and guide clinical treatment, we explore the application of α values generated from stretched-exponential models of intravoxel incoherent motion (IVIM) in diagnosing the stage IA and IB of endometrial carcinoma.Methods
Twenty six pathologically proved patients were enrolled, classifying into two groups as follows: 15 in stage IA and 11 in stage IB. IVIM sequence with 11 b values (0, 20，50，100，150，200，400，800，1200，2000，3000 mm/s2) was performed using a 3.0 T system before treatment. The α maps were reconstructed and mean α values were calculated. The placement of ROI aimed to comprise the maximum axial tumor parenchyma area, avoiding inclusion of normal myometrial tissue and necrotic or hemorrhagic areas if present. ROC analysis was performed to evaluate the diagnostic performance and to discover the corresponding threshold.Results
Mean α values of stage IA and stage IB groups were (0.67±0.06), (0.71±0.05), respectively. There was statistic difference between two groups (P=0.024). The area under ROC curve of α value of different stages was 0.764, with sensitivity of 66.7% and specificity of 90.9% when the critical value was 0.67.Discussion
IVIM MRI is an extension of DWI that enables the simultaneous acquisition of both microcirculatory and diffusivity information[3]. And α is the stretching parameter, which characterizes the deviation of the signal attenuation from monoexponential behavior, and is limited to values between zero and one[4]. A value of α that is near one indicates high homogeneity in apparent diffusion. This study showed that endometrial carcinoma at stage IB had higher α value, suggested higher homogeneity in apparent diffusion, than endometrial carcinoma at stage IA.Conclusion
The heterogeneity of intravoxel diffusion (α) of IVIM MR can be used to distinguish stage IA or IB of endometrial carcinoma specifically, and has potential value to be a non-enhancement quantitative index for staging endometrial carcinoma.Acknowledgements
No acknowledgement found.References
[1] Beddy P, O'Neill A C, Yamamoto A K, et al. FIGO staging system for endometrial cancer: Added benefits of MR imaging. Radiographics, 2012, 32(1):241.
[2] Beddy P,Moyle P,Kataoka M,et al. Evaluation of depth of myometrial invasion and overall staging in endometrial cancer: Comparison of diffusion- weighted and dynamic contrast-enhanced MR imaging. Radiology,2012,262(2):530-537.
[3] Liu J, Wan Y, Wang Z, et al. Perfusion and diffusion characteristics of endometrial malignancy based on intravoxel incoherent motion MRI at 3.0 T: comparison with normal endometrium. Acta Radiologica, 2016, 57(9): 1140-1148.
[4] Bennett K M, Schmainda K M, Bennett R, et al. Characterization of continuously distributed cortical water diffusion rates with a stretched-exponential model. Magnetic Resonance in Medicine, 2003, 50(4):727-734.
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