Exploring the impact of the female thoracic size, breast size and image receptor angles on the volume of missing breast tissue in mammographic imaging

Abstract

INTRODUCTION : Optimal positioning in mammography and subsequent image quality can be impacted by thorax variability, breast size and the chosen image receptor (IR) angles. This study aims to explore the impact of the female thoracic size, breast size and IR angle on the volume of missing breast tissue (MBT) in mammographic imaging. METHODS : Sixty-three images were recorded: one craniocaudal (CC) at an IR angle of 0° for three sized breast phantoms attached to three sized thoracic models; and six mediolateral obliques (MLOs) at IR angles of 30°, 40°, 45°, 50°, 55°, 60° for three sized breast phantoms attached to three sized thorax models. Breast size was determined using the posterior nipple line (PNL) measurement and were recorded in millimetres. Breast volume was recorded in cubic centimetres. RESULTS : The breast size and breast tissue volume of a small thorax and large breasts was better visualised with increasing IR angles. Optimal MLO IR angles were determined for the combined average thorax with average breast at 55° and large thorax with large breast at 40° with minimum MBT values of 51.33 cm3 and 75.07 cm3, respectively. Female thoracic size, IR angle, and breast size are significant (p < 0.01) and have a positive impact on the volume of MBT. CONCLUSION : Optimal MLO IR angles were determined for the three breast phantoms attached to three thoracic models. Female thoracic size positively impacts the volume of MBT and in terms of clinical practice it is vital to adjust the MLO IR angle to ensure maximum breast tissue coverage. IMPLICATIONS FOR PRACTICE : These findings can be modelled in current clinical practice on women presented for mammography examinations with varying thorax and breast sizes, allowing optimal IR angle selection and therefore resulting in improved breast tissue inclusion and subsequently a more accurate breast cancer diagnosis.