Reproducibility of the interpretation of hysterosalpingography in the diagnosis of tubal pathology

The aim of the study was to estimate the inter- and intra-observer reproducibility of the interpretation of hysterosalpingography (HSG) in the diagnosis of tubal pathology, and associate reproducibility with diagnostic accuracy. Four observers evaluated 143 HSGs twice, on proximal tubal obstruction, distal tubal obstruction, hydrosalpinx and peritubal adhesions. Diagnostic laparoscopy with chromopertubation was considered to be the reference strategy, Reproducibility (inter- and intra-observer agreement) was expressed in terms of κ-values. Accuracy was expressed in terms of sensitivity, specificity and likelihood ratios, κ-values for reproducibility between observers were almost perfect for proximal obstruction, substantial for distal obstruction and hydrosalpinx, and moderate for adhesions. κ-values for reproducibility within observers were almost perfect for proximal obstruction and substantial for distal obstruction, hydrosalpinx and adhesions. HSG had a high specificity for proximal obstruction, but a low sensitivity. Distal obstruction, absence of hydrosalpinx and adhesions had a poor accuracy. The likelihood ratio for the presence of hydrosalpinx was high. In conclusion, proximal tubal obstruction detected on HSG changes the pre-test probability of proximal tubal obstruction from 16 to 50%. Proximal tubal patency detected on HSG changes the pre-test probability of proximal tubal patency from 16 to 9%. It is unlikely that a lack of reproducibility of the interpretation of proximal tubal patency is responsible for the low sensitivity; alternative explanations are artefacts occurring while performing HSG or an imperfect reference strategy diagnostic laparoscopy. HSG is of limited use in diagnosing distal tubal obstruction and hydrosalpinx, and has no value in the detection of peritubal adhesions.