Amide Proton Transfer‐Weighted Imaging Combined With Intravoxel Incoherent Motion for Evaluating Microsatellite Instability in Endometrial Cancer

Abstract

Background Microsatellite instability (MSI), caused by mismatch repair (MMR) protein defects that lead to uncorrectable mismatch bases, results in the accumulation of gene mutations and ultimately to tumors. Preoperative prediction of MSI can provide a basis for personalized and precise treatment of endometrial cancer (EC) patients. Purpose To investigate amide proton transfer weighting (APTw) imaging combined with intravoxel incoherent motion (IVIM) in the assessment of MSI in EC. Study Type Retrospective. Population A total of 71 patients with EC (12 classified as the MSI group and 22 as the microsatellite stabilization [MSS] group after entering and leaving the group standard). Field Strength/Sequence A 3.0 T/IVIM, diffusion‐weighted imaging (DWI) and APTw. Assessment Amide proton transfer (APT) value, apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudo diffusion coefficient (D*), and perfusion fraction (f) were calculated and compared between MSI and MSS groups. Statistical Tests The Kendall's W test; Mann–Whitney U‐test; Chi‐square test or Fisher's exact test; logistic regression analysis; Area under the receiver operating characteristic (ROC) curve (AUC); The Delong test; Pearson or Spearman correlation coefficients. The significance threshold was set at P < 0.05. Results APT and D* values of the MSI group were significantly higher than those of the MSS group. While ADC, D, and f values in the MSI group were significantly lower than those in the MSS group. The multivariate analysis revealed that only APT and D* values were independent predictors to evaluate the MSI status. And the ROC curves indicated that the combination of APT and D* values could distinguish the MSI status of EC with the highest diagnostic efficacy (AUC = 0.973), even without significant difference to those by APT (AUC = 0.894) or D* (AUC = 0.920) value separately (P = 0.149 and 0.078, respectively). Conclusion Combination of APTw and IVIM imaging may serve as an effective noninvasive method for clinical assessment of MSI in EC. Evidence Level 3 Technical Efficacy Stage 2

A comparative study of mono-exponential and advanced diffusion-weighted imaging in differentiating stage IA endometrial carcinoma from benign endometrial lesions

“…The D and D* values derived from the bi-exponential IVIM model reflect the diffusion of water molecules and micro-perfusion separately. The IVIM method was shown to be useful in the assessment of the biological behaviour of EC (Meng et al 2021a ), as well as the correlation of cell proliferation with antigen Ki-67 (Li et al 2021 ) and the microsatellite instability status of EC (Ma et al 2023 ; Bhosale et al 2017 ). In our study, the D value of the IAEC group was lower than that of the BEL group, whereas the D* value of the IAEC group was higher compared with the BEL group.…”

“…Intravoxel incoherent motion includes bi-exponential and stretched-exponential models and is used to reflect capillary microcirculatory perfusion, while DKI describes tissue heterogeneity. The IVIM model was previously found to be related to pathological indicators and useful for the disease grading of EC (Ma et al 2023 ; Satta et al 2021 ; Chryssou et al 2022 ); it also showed higher efficacy than ADC in differentiating an endometrial malignancy from the normal endometrium (Liu et al 2016 ). Diffusion kurtosis imaging is based on the non-Gaussian model and has a high sensitivity for reflecting the complexity of the tissue microstructure (Jensen et al 2005 ).…”

The value of multimodal functional magnetic resonance imaging in differentiating p53abn from p53wt endometrial carcinoma

“…In addition, Li et al (16) showed that the APT value was moderately positively correlated with the expression index of the nuclear antigen Ki-67 associated with EC cell proliferation. Moreover, Ma et al (17) showed that the APT value could effectively predict EC microsatellite instability status.…”

Editorial for “Amide Proton Transfer‐Weighted Imaging Combined With Intravoxel Incoherent Motion for Evaluating Microsatellite Instability in Endometrial Cancer”

“…two of these techniques, amide proton transfer (APT) and intravoxel incoherent motion (IVIM) MRI to identify endometrial cancers with microsatellite instability. 7 Amide proton transfer (APT) MRI is a subset of the chemical exchange saturation transfer (CEST) MRI technique which utilizes the chemical exchange of endogenous amide protons to generate contrast in the bulk water signal by off resonance saturation of the amide proton frequency. The decrease in bulk water signal is dependent on the endogenous amide proton concentration and pH within the voxel.…”

“…10 Ma et al in this issue show that microsatellite instability in endometrial cancer can be correlated with D*, the blood circulation, and APT value and the combination was a better predictor of MSI status than separately. 7 This study is very small and these parameters have notable variability based on imaging and analysis techniques; however, this work is interesting in that it offers a potential MRI application, which correlates with the molecular profile of a tumor that is already used to guide therapy decisions. Imaging assessment of microsatellite instability could be used to complement pathologic assessment and identify patients who may be misclassified by pathology due to sampling bias or inconclusive assessment.…”