Evaluating the utility of enhanced T1 mapping MR imaging in assessing depth of myometrial invasion and detecting DNA mismatch repair status in endometrial cancer: a pilot study

Abstract

Objectives: To evaluate the value of enhanced T1 mapping MR imaging in assessing the depth of myometrial invasion (MI) and in detecting DNA mismatch repair (MMR) status in endometrial cancer (EC) as a non-invasive imaging biomarker.

Methods: This prospective study enrolled 46 patients with pathologically confirmed EC who underwent pelvic MRI and surgery within two weeks. Each patient underwent multiparametric MRI including T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), dynamic contrast-enhanced imaging (DCE), native T1 mapping and enhanced T1 mapping. Four radiologists (two junior, two senior) independently assessed MI depth of EC using two combinations: T2WI + DWI + DCE and T2WI + DWI + enhanced T1 mapping. Histopathology served as the reference standard. MMR status was determined by immunohistochemistry. Quantitative analysis of native T1, enhanced T1, and Apparent diffusion coefficient (ADC) values was performed, and inter-reader agreement and diagnostic performance were compared. Receiver operating characteristic curve (ROC) analysis was performed. Statistical significance was set at p < 0.05.

Results: The diagnostic accuracy of T2WI + DWI + enhanced T1 mapping for assessing MI was higher than that of T2WI + DWI + DCE across all readers, especially among junior radiologists, though differences were not statistically significant (P > 0.05). Inter-reader agreement improved with enhanced T1 mapping, particularly for junior readers (κ = 0.898 vs. κ = 0.538). Native T1 values were significantly higher in the proficient MMR group compared to the deficient MMR group (1655.5 ± 131.9 ms vs. 1549.1 ± 125.9 ms, P = 0.047). ROC analysis yielded an Area under the curve (AUC) of 0.729 for differentiating deficient MMR from proficient MMR, with a sensitivity of 87.0% and specificity of 67.7% at a cutoff of 1524.7 ms.

Conclusion: Enhanced T1 mapping, when incorporated into routine MR protocols, offers diagnostic performance comparable to DCE for evaluating myometrial invasion in endometrial cancer and significantly improves inter-reader agreement. Native T1 values show promise as a non-invasive biomarker for detecting MMR status in EC.

Keywords: Deficient mismatch repair; Dynamic contrast-enhanced imaging; Endometrial cancer; Magnetic resonance imaging; T1 mapping.