breast volume breast volume breast volume is a method of measuring the size of the breasts. a variety of techniques have been used to measure breast volume, including water displacement, medical imaging (e.g., mammography, magnetic resonance imaging (mri), ultrasound), and 3d scanning. there is substantial measurement error with many breast volume measures, but mri imaging appears to have among the lowest error and hence to be the most accurate measure. however, 3d scanning might have the potential to become the new gold standard for clinical assessment.