The feasibility of high-resolution organ-axial T2-weighted MRI when combined with federation of gynecology and obstetrics (FIGO) classification of uterine fibroid patients.

Abstract

Purpose: Correctly classifying uterine fibroids is essential for treatment planning. The objective of this study was to assess the accuracy and reliability of the FIGO classification system in categorizing uterine fibroids via organ-axial T2WI and to further investigate the factors associated with uterine compression.

Methods: A total of 130 patients with ultrasound-confirmed fibroids were prospectively enrolled between March 2023 and May 2024. These patients underwent MR examinations, including body-axial T2W (sagittal and axial) and organ-axial T2W (high resolution with oblique coronal and double oblique axial). For postprocessing, the interobserver agreements between two radiologists and the interagreements between two MR examinations and operational descriptions were evaluated via kappa statistics. The accuracy of axial and organ-axial T2W assessments in the FIGO classification of uterine fibroids was compared when surgical outcomes were used as the gold standard. The Kruskal‒Wallis test was used to compare the differences in cavity deformation across various FIGO classifications. Spearman's rank correlation test was used to analyze the correlation between the FIGO classification and the parameters of uterine cavity deformation.

Results: In total, 170 fibroids from 130 patients were included. Compared with body-axial T2WI, organ-axial T2WI showed better interobserver agreement and greater interagreements with operational descriptions, with kappa values of 0.877 (P = 0.04) and 0.932 (P = 0.037), respectively. The accuracy of the organ-axial T2WI assessment in determining the FIGO classification of uterine fibroids was greater than that of the body-axial T2WI assessment, with an accuracy of 92.9% (P < 0.01). Thirty-two (38.1%) fibroids showed cavity deformation according to organ-axial T2WI, including fibroids with FIGO types 0-7 and 2-5. Among these factors, the size of the fibroids (S), base width (B), depth of compression (D), D/B, D/S, and compression angle (A) significantly differed among the different FIGO types of fibroids (P < 0.05). Compression angle exhibited a linear correlation with the FIGO type (P < 0.001).

Conclusion: Compared with body-axial T2WI, organ-axial T2WI provides greater accuracy on the basis of the FIGO classification, which is more consistent with surgical outcomes. Given the excellent reliability and accuracy of the preoperative FIGO classification, organ-axial T2WI can contribute to treatment planning.