Comparison between Transvaginal Ultrasound and Normal Saline Sonohysterography in the Evaluation of Cesarean Niche

Purpose: The rate of Cesarean section (CS) continues to rise in modern obstetric practice. Women who have undergone CS are at risk of developing various complications, including the formation of a Cesarean scar defect (CSD), also referred to as a uterine niche. This study was designed to determine the prevalence of CSD and to compare the diagnostic accuracy of transvaginal ultrasound (TVUS) with sonohysterography (SHG).Patients and Methods: In this prospective investigation, women were examined three months after CS. Each participant underwent thorough history taking, clinical assessment, and imaging evaluation using both TVUS and SHG, performed during the postmenstrual period. CSDs were assessed in the longitudinal plane, and when detected, measurements were taken for depth, width, residual myometrial thickness (RMT), and adjacent myometrial thickness (AMT).Results: We included 500 women. A total of 37.2% of patients were found to have CSDs through TVUS, while 63.4% were identified using SHG. For the detection of the niche, TVUS exhibited a sensitivity of 58.7%, while achieving a specificity of 100. In the detection of niches with low residual RMT (<3 mm), TVUS demonstrates a sensitivity of 31.1%, coupled with a specificity of 100%, indicating its accuracy in excluding cases without low RMT. Conclusion: This study revealed a considerable prevalence of CSD. SHG was more sensitive in the detection of CSD, and both demonstrated high specificity (100%). SHG was also more accurate in the detection of low thickness CSD and in the assessment of CSDs measures at all.