The reliability and distinguishability of ultrasound diagnosis of ovarian masses.

BACKGROUND For any radiologist, intra-observer agreement in observing and decision making in diagnosis of any disease is of great importance, and so is observing and reading ultrasound pictures of ovarian masses and distinguishing amongst their categories. AIMS In this study, the reliability and consistency of ultrasound diagnosis of ovarian tumors have been evaluated. SETTINGS AND DESIGN Two experienced and three less experienced radiologists assessed ultrasounds of 40 patients of Mirza Koochak Khan Hospital in Tehran, Iran, in 2005. MATERIALS AND METHODS In this prospective observational study, the ultrasounds were performed by an expert radiologist, with a single apparatus. These ultrasounds have been evaluated separately and independently in two periods (with a 1-week interval). STATISTICAL ANALYSIS USED Weighted kappa was used to calculate intra-observer agreement (reliability), and two statistical models were applied to assess category distinguishability (consistency). SPSS version 10, SAS version 8, and EXCEL 2003 have been used to do an appropriate statistical analysis. RESULTS Mean of weighted kappa was 0.81, and mean of distinguishability was 0.995 for our experienced radiologists, due to their superior results. Because of weaker results obtained by the less experienced radiologists, mean of weighted kappa and mean of distinguishability were 0.65 and 0.967 respectively. Overall mean of distinguishability for benign and borderline categories was 0.969; and for malignant and borderline categories, it was 0.987. CONCLUSION Although experienced radiologists functioned better than the less experienced radiologists, all of them showed appropriate distinguishability and intra-observer agreement in diagnosis and categorization of the ovarian masses. Distinguishing benign category from borderline was more difficult than distinguishing malignant category from borderline. In general, experienced radiologists showed better results compared to less experienced radiologists.