Diagnostic accuracy of saline infusion sonography in the evaluation of uterine cavity abnormalities prior to assisted reproductive techniques: a systematic review and meta-analyses

Background: The diagnostic accuracy of a 2-D transvaginal scan, which is commonly employed to evaluate the regularity and shape of the uterine cavity in subfertile women, is relatively poor compared with other diagnostic modalities like saline infusion sonography (SIS) or hysteroscopy. SIS is a minimally invasive, cost-effective and acceptable diagnostic modality. Therefore the aim of this systematic review was to assess the diagnostic accuracy of SIS in the evaluation of the uterine cavity in subfertile women. Methods: A systematic review was conducted of diagnostic studies that compared SIS with hysteroscopy. Twenty relevant studies (including 1645 procedures) were identified and a subsequent meta-analysis was performed. Electronic databases were searched for relevant studies and references of relevant studies were cross checked. Validity was assessed and data were extracted independently by two authors. Heterogeneity was examined, studies were plotted in an ROC area and data were pooled. The main outcome measure was the diagnostic accuracy of saline infusion sonography. The pooled sensitivity, specificity, likelihood ratios and the post-test probabilities of saline infusion sonography on the prediction of uterine cavity abnormalities were calculated. Results: The pooled sensitivity of SIS in the detection of all intrauterine abnormalities was 0.88 (95% confidence interval (CI): 0.85-0.90). The pooled specificity was 0.94 (95% CI 0.93-0.96). The positive and negative likelihood ratios were 20.93 (95% CI: 9.06-48.34) and 0.15 (95% CI: 0.10-0.22), respectively. SIS had good accuracy in the detection of all intrauterine abnormalities (area under the summary receiver operating curve (sROC) = 0.97 +/- 0.01). SIS also had a high pooled sensitivity and specificity in the detection of congenital uterine anomalies, 0.85 (95% CI: 0.79-0.90) and 1.00 (95% CI 0.99-1.00), respectively. However the limitations of the review include the heterogeneity amongst the included studies. Conclusions: SIS is a highly sensitive investigative modality and comparable to the gold standard tool, hysteroscopy in the detection of intrauterine abnormalities in subfertile women. SIS is a highly sensitive and specific test in the diagnosis of uterine polyps, submucous myomas, uterine anomalies and intrauterine adhesions and can be used as a screening tool for subfertile patients prior to IVF treatment.