Prevalence of isthmocele according to diagnostic hysteroscopy, transvaginal ultrasound, and magnetic resonance imaging in non-pregnant women: cross-sectional study.

OBJECTIVE: The aim of this study was to estimate the prevalence of isthmocele using transvaginal ultrasound, magnetic resonance imaging and diagnostic hysteroscopy. METHODS: A cross-sectional study conducted from 2020 to 2022 in tertiary academic hospital with ninety non-pregnant women with a history of cesarean section. Transvaginal ultrasound (n=90), magnetic resonance imaging (n=65) and office diagnostic hysteroscopy (n=81) were performed within a short interval for each patient. RESULTS: The women had a mean age of 34.8±6.3 years, mean number of 2.0±1.1 cesarean sections and mean duration of 40 months since their last cesarean. The prevalence of isthmocele with 95%CIs was 11.3% (5.5-19.7%) on transvaginal ultrasound, 66.1% (53.3-77.4%) on magnetic resonance imaging, and 43.2% (32.2-54.6%) on diagnostic hysteroscopy. When transvaginal ultrasound was considered reference, accuracy for diagnostic hysteroscopy was 57.89% (44.1%; 70.6%) and magnetic resonance imaging, 43.86% (30.9; 57.5%); when magnetic resonance imaging was reference, accuracy for diagnostic hysteroscopy was 54.39% (40.75; 67.43%). Agreement analysis (kappa) among the methods showed low scores between diagnostic hysteroscopy and magnetic resonance imaging regarding transvaginal ultrasound (0.126, p<0.001 and 0.103, p<0.001, respectively) and between diagnostic hysteroscopy and magnetic resonance imaging (0.206, p=0.014). CONCLUSION: The prevalence of isthmocele was lower in transvaginal ultrasound and higher in magnetic resonance imaging. Accuracy varied from 43 to 58% among the three methods and agreement between tests for diagnosing isthmocele was low.