MRI screening for uterine leiomyosarcoma

Background: Uterine fibroids are a common benign tumor and can be symptomatic, necessitating resection. Surgical myomectomy is an effective treatment option with a risk of disseminating occult uterine leiomyosarcoma (LMS), creating a need for an effective presurgical screening protocol. Clinical collaboration with contrast-enhanced MRI including T₂ and diffusion-weighted imaging (DWI) can be utilized as a screening exam.

Purpose: To review the accuracy and feasibility of an interdisciplinary prospective contrast-enhanced MRI pelvis with DWI screening system for LMS prior to fibroid resection.

Study type: Retrospective cohort study.

Population: In all, 1960 adult female patients aged 18-87 undergoing screening MRI pelvis prior to uterine fibroid resection.

Field strength/sequence: T₁ and T₂ -weighted imaging, DWI, and contrast-enhanced images were acquired at 1.5 T and 3.0 T.

Assessment: Each radiologist at the time of clinical study prospectively designated a confidence level of presence of LMS in the impression, which was reviewed retrospectively. A separate retrospective evaluation of the histologically proven LMS and the false positives was performed for the presence of five MRI features of LMS including low ADC values, intermediate/high T₂ signal intensity, irregular margins, hemorrhage, and necrosis. A preliminary cost-effectiveness analysis was performed, comparing the costs of treatment of uterine fibroids with vs. without a collaborative screening protocol using MRI.

Statistical tests: Sensitivity, specificity, positive predictive value, and negative predictive value were obtained from the prospective evaluations. Student's t-tests were used to compare demographics and apparent diffusion coefficient values between LMS and false-positive results.

Results: We prospectively identified LMS patients with 100% sensitivity and 97% specificity. Preliminary cost analysis demonstrated that the MR screening protocol increased life expectancy by 0.04 years at a cost of $12,937 per life-year gained.

Data conclusion: MRI is an effective and potentially economic screening test, especially with standardized reporting and coordination with clinicians.

Level of evidence: 3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019.