Evaluation of the state of the uterine scar after cesarean section using magnetic resonance imaging in the diagnosis of «niche»: a retrospective study

INTRODUCTION : The increasing frequency of cesarean section has led to a rise in postoperative complications. One of these complications is the formation of a «niche» in the uterine scar. To determine the appropriate management strategy for patients at the preconception stage, it is essential to thoroughly assess the condition of the postoperative scar. OBJECTIVE : Evaluate the effectiveness of magnetic resonance imaging (MRI) in assessing the condition of the uterine scar niche following cesarean section. MATERIALS AND METHODS : A retrospective analysis was performed on 63 pelvic MRI scans (1.5/3.0 T) of women aged 18– 45 years with a uterine niche after cesarean section (residual myometrial thickness < 3 mm). Two radiologists independently assessed scar morphometric parameters in T2-weighted imaging. Measurements were performed using RadiAnt DICOM Viewer. Statistical analysis was conducted using StatTech v. 4.8.0 (StatTech LLC, Russia). RESULTS : The analysis of MRI data showed that the residual thickness of the myometrium was 2.5 (2.0; 3.0) mm, with the median depth of the «niche» 5.0 (4.0; 6.2) mm, width 8.0 (6.0; 12.0) mm, and length 9.5 (7.0; 12.0) mm (n=63). The thickness of the adjacent myometrium was 12.0 (10.75; 15.0) mm, and the distance to the external cervical os was 28.0 (24.0; 30.0) mm. The prevalence of minor defects in the scar was 85.7% (54/63), while significant defects were observed in 14.3% (9/63) of patients. An inverse correlation was found between the myometrial thickness and the length of the «niche» (rs=–0.160, p=0.21), and between the residual myometrial thickness and the depth of the «niche» (rs=–0.256, p=0.042). DISCUSSION : The use of magnetic resonance imaging (MRI) in the diagnosis of uterine scars provides high visualization accuracy and minimizes subjective influences from experts. MRI can be a useful tool for predicting the effectiveness of surgical treatment. Correlation analysis demonstrated that deeper and longer scar defects are associated with a reduction in the thickness of the residual myometrium. CONCLUSION: During the preconception period, it is crucial to obtain detailed data on the condition of the scar. To achieve this, an extended protocol for measuring the scar should be used. A thorough description of the scar’s structure will help clinicians make informed decisions regarding the further management of patients.