Comparison of transvaginal ultrasound and saline contrast sonohysterography in evaluation of cesarean scar defect: a prospective cohort study

IntroductionThe aim of this study was to investigate the prevalence of post-cesarean isthmocele and to measure agreement between transvaginal ultrasonography and saline contrast sonohysterography in assessment of isthmocele. Material and methodsA prospective observational cohort study was carried out at Tampere University Hospital, Finland. Non-pregnant women delivered by cesarean section (n = 371) were examined with transvaginal ultrasonography (TVUS) and sonohysterography (SHG) six months after cesarean section. The main outcome measure was the prevalence of isthmocele using TVUS and SHG. Secondary outcome measures were characteristics of isthmocele. ResultsIn all, 371 women were included. The prevalence of isthmocele was 22.4% based on TVUS and 45.6% based on SHG. Sensitivity and specificity for TVUS was 49.1 and 100%, respectively, when compared with SHG. Therefore, half of the defects (50.9%) diagnosed with SHG remained undiagnosed with TVUS. Bland-Altman analysis showed an underestimation of 1.1 mm (range 0.00-7.90) for TVUS compared with SHG, with 95% limits of agreement from -1.9 to 4.1 mm. ConclusionsThis methodological study provides confirmatory data that TVUS and SHG are not in good agreement in the isthmocele diagnostics and the use of only TVUS may lead to an underestimation of the prevalence of isthmocele. Thus, SHG should be considered as a method of choice in diagnostics of isthmocele.