Quantification of Endometrial Fibrosis Using Noninvasive MRI T2 Mapping: Initial Findings.

Background: Endometrial fibrosis may cause infertility. Accurate evaluation of endometrial fibrosis helps clinicians to schedule timely therapy.

Purpose: To explore T2 mapping for assessing endometrial fibrosis.

Study Type: Prospective.

Population: Ninety-seven women with severe endometrial fibrosis (SEF) and 21 patients with mild to moderate endometrial fibrosis (MMEF), diagnosed by hysteroscopy, and 37 healthy women.

Field Strength/sequence: 3T, T2-weighted turbo spin echo (T2-weighted imaging) and multi-echo turbo spin echo (T2 mapping) sequences.

Assessment: Endometrial MRI parameters (T2, thickness [ET], area [EA], and volume [EV]) were measured by N.Z. and Q.H. (9- and 4-years' experience in pelvic MRI) and compared between the three subgroups. A multivariable model including MRI parameters and clinical variables (including age and body mass index [BMI]) was developed to predict endometrial fibrosis assessed by hysteroscopy.

Statistical Tests: Kruskal-Wallis; ANOVA; Spearman's correlation coefficient (rho); area under the receiver operating characteristic curve (AUC); binary logistic regression; intraclass correlation coefficient (ICC). P value <0.05 for statistical significance.

Results: Endometrial T2, ET, EA, and EV of MMEF patients (185 msec, 8.2 mm, 168 mm , and 2181 mm ) and SEF patients (164 msec, 6.7 mm, 120 mm , and 1762 mm ) were significantly lower than those of healthy women (222 msec, 11.7 mm, 316 mm , and 3960 mm ). Endometrial T2 and ET of SEF patients were significantly lower than those of MMEF patients. Endometrial T2, ET, EA, and EV were significantly correlated to the degree of endometrial fibrosis (rho = -0.623, -0.695, -0.694, -0.595). There were significant strong correlations between ET, EA, and EV in healthy women and MMEF patients (rho = 0.850-0.908). Endometrial MRI parameters and the multivariable model accurately distinguished MMEF or SEF from normal endometrium (AUCs >0.800). Age, BMI, and MRI parameters in univariable analysis and age and T2 in multivariable analysis significantly predicted endometrial fibrosis. The reproducibility of MRI parameters was excellent (ICC, 0.859-0.980).

Data Conclusion: T2 mapping has potential to noninvasively and quantitatively evaluate the degree of endometrial fibrosis.

Evidence Level: 2 Technical Efficacy: Stage 2.