Labeling of meridional and radial scans of the breast

Meridional and radial scanning of the breast follows the anatomic planes of the breast. The scans at the 90 degrees and 180 degrees axes correspond to the lateral and cephalocaudal x-ray mammograms, respectively. Meridional scanning introduces unique problems of orientation and labeling. The labeling methods suggested in this paper result in comparable portions of each breast lying along identical planes of scan. An equation and a table that define the minimal angular increment required to detect a 0.5-cm lesion at the periphery of the breast are presented. Forms for converting meridional scans to orthogonal localization are also presented. In our hands, this method of labeling has proved to be simpler than that suggested by the American Institute of Ultrasound in Medicine.