Evaluation of the pectoral muslce in mammography images : the Australian experience

Introduction: Critical to the success of early breast cancer detection is the consistent production of high quality mammographic images. Image evaluation systems are used to evaluate mammographic image quality and must be reliable and valid. This study set out to investigate radiographers’ perceptions of the current image evaluation systems such as the PGMI as well as their interpretation of criteria relating to the presentation of the pectoral muscle in the mediolateral oblique view. Method: A survey method was employed for this exploratory study as a way of collecting data from the largest possible sample. Surveys were distributed to radiographers employed in all different types of work in mammography. Following collation of responses descriptive statistics were developed. Thematic analysis was applied to the responses to the open-ended questions. Results: One hundred and sixty eight surveys were returned. The questionnaire responses were grouped into two categories: image evaluation systems and the presentation of the pectoral muscle. Overall the study results demonstrate variations in Australian radiographers’ practice when evaluating mammogram images. Conclusion: The study demonstrated worrying variations in the interpretation of criteria in current image evaluation systems. Inconsistent interpretation of criteria relating to the presentation of the pectoral muscle increases the risk of breast tissue not being included in the image. This study has provided evidence for the need for clearly defined criteria using objective measures so that the subjectivity of interpretation is minimised.