Endometrial Cancer: Combined MR Volumetry and Diffusion-weighted Imaging for Assessment of Myometrial and Lymphovascular Invasion and Tumor Grade

Abstract

Purpose:To investigate magnetic resonance (MR) volumetry of endometrial tumors and its association with deep myometrial invasion, tumor grade, and lymphovascular invasion and to assess the value of apparent diffusion coefficient (ADC) histographic analysis of the whole tumor volume for prediction of tumor grade and lymphovascular invasion. Materials and Methods:The institutional review board approved this retrospective study; patient consent was not required. Between May 2010 and May 2012, 70 women (mean age, 64 years; range, 24-91 years) with endometrial cancer underwent preoperative MR imaging, including axial oblique and sagittal T2-weighted, dynamic contrast material-enhanced, and diffusion-weighted imaging. Volumetry of the tumor and uterus was performed during the six sequences, with manual tracing of each section, and the tumor volume ratio (TVR) was calculated. ADC histograms were generated from pixel ADCs from the whole tumor volume. The threshold of TVR associated with myometrial invasion was assessed by using receiver operating characteristic curves. An independent sample Mann Whitney U test was used to compare differences in ADCs, skewness, and kurtosis between tumor grade and the presence of lymphovascular invasion. Results:No significant difference in tumor volume and TVR was found among the six MR imaging sequences (P = .95 and .86, respectively). A TVR greater than or equal to 25% allowed prediction of deep myometrial invasion with sensitivity of 100% and specificity of 93% (area under the curve, 0.96; 95% confidence interval: 0.86, 0.99) at axial oblique diffusion-weighted imaging. A TVR of greater than or equal to 25% was associated with grade 3 tumors (P = .0007) and with lymphovascular invasion (P , .0001).There was no significant difference in the ADCs between grades 1 and 2 tumors (P . .05). The minimum, 10th, 25th, 50th, 75th, and 90th percentile ADCs were significantly lower in grade 3 tumors than in grades 1 and 2 tumors (P , .02). Conclusion:The combination of whole tumor volume and ADC can be used for prediction of tumor grade, lymphovascular invasion, and depth of myometrial invasion.q RSNA, 2015

Preoperative Magnetic Resonance Volumetry in Predicting Myometrial Invasion, Lymphovascular Space Invasion, and Tumor Grade: Is It Valuable in International Federation of Gynecology and Obstetrics Stage I Endometrial Cancer?

“…Second, MR volumetry was performed on a single type of MRI sequence (sagittal T2-weighted image). Nougaret et al 15 suggested that only 1 sequence is necessary to measure tumor volume correctly owing to high reproducibility of tumor volume and TVR between 6 different sequences. Therefore, this limitation might not have an important impact.…”

“…Nougaret et al 15 proposed that an endometrial TVR greater than or equal to 25% allowed prediction of deep myometrial invasion with sensitivity of 100% and specificity of 93%, prediction of grade 3 tumors with sensitivity of 83% and specificity of 65%, and prediction of LVSI with sensitivity of 77% and specificity of 83%. Although we used the same measurement method in MR volumetry and have similar number of patient population compared to their study (68 vs 70), our threshold value for TVR for predicting deep myometrial invasion was much lower with lower AUC in statistical analysis.…”

“…13Y15 A recent study showed the association of endometrial tumor volumetry and deep myometrial invasion, tumor grade, and LVSI. 15 In that study, Nougaret et al 15 assumed that a tumor volume ratio (TVR) greater than or equal to 25% allowed prediction of deep myometrial invasion with sensitivity of 100% and specificity of 93%, and it was associated with grade 3 tumors and LVSI. In another study focusing on diffusion weighted MR imaging of endometrial cancer, diffusion volume of the tumor was shown to be an accurate index for the assessment of grade and risk classification.…”

A Predictor of Tumor Recurrence in Patients With Endometrial Carcinoma After Complete Resection of the Tumor: The Role of Pretreatment Apparent Diffusion Coefficient

“…We used singular round/oval ROI, whereas Nakamura et al 23 34 Recently, volumetric histogram analysis has been applied for patients with cervical and endometrial carcinoma to reduce the influence of such artifacts and sampling biases. 30 Although volumetric analysis was not used because it is time consuming for clinical use and because it entails difficulty in delineating outlines and avoiding cystic portion in several cases. Results showed that lower ADC values predict worse prognosis, independent of the histological grade.…”

Diffusion-weighted magnetic resonance imaging in cancer: Reported apparent diffusion coefficients,in-vitroandin-vivoreproducibility

“…Tamai et al [88] demonstrated that there was no overlap between ADC values in normal endometrium and endometrial cancers. Nougaret et al [93] found a significant difference in the ADC values of grade 3 endometrial tumours compared to those of grade 1 and 2. However, in adjacent myometrium differentiating between benign and malignant disease based on ADC values alone is difficult [94] .…”