An evaluation of the inter-observer and intra-observer variability of the ultrasound diagnosis of polycystic ovaries

BACKGROUND: This prospective observational study was undertaken to evaluate the reliability and consistency of ultrasound diagnosis of polycystic ovarian syndrome (PCOS). METHODS: Eighteen women with clinical and biochemical features suggestive of PCOS and nine normal control women underwent transvaginal ultrasound scan by a single ultrasonographer. The 27 ovarian scans were video-recorded and the recordings were later edited and arranged randomly so that each record appeared twice at random on the tape producing a total of 54 ovarian scans. Four experienced observers independently reviewed the recordings. The observers scored each case as follows: normal, possible polycystic ovary (PCO) and definite PCO. RESULTS: The mean intra-observer agreement was 69.4% (kappa = 0.54) and the mean inter-observer agreement was 51% (kappa = 0.28). CONCLUSION: The results suggest that the currently used ultrasonographic criteria for the diagnosis of polycystic ovaries do have significant intra-observer and inter-observer variability and as such must be considered subjective. Transvaginal ultrasonography alone may not therefore be a reliable method of diagnosing or excluding PCOS.