Breast sonography: technique to mimic mammographic position

Positional changes in the breast between supine sonography and mammography may cause difficulties in correlating abnormalities. The problem is easily surmounted by performing the breast sonogram with the patient in the upright position. This study is a prospective evaluation of 10 patients examined sonographically in the supine and upright positions. The nipple to lesion distance was measured and the clock position estimated on the upright and supine sonograms. These parameters were compared to the original mammograms. In all patients the mammographic clock position and the distances from the nipple correlated more closely with the upright sonogram. The mammographic clock position was the same on the upright sonogram in six of 10 (60%), and the remaining four (40%) varied from one half to two clock positions. In supine sonography the clock position was the same in two of 10 (20%) patients, and the remaining eight (80%) varied from one to three clock positions. Most lesions were between 4.5 and 11 cm from the nipple on the mammogram. The distances of the lesions from the nipple ranged from 3 to 10 cm on upright sonography and from 0 to 4.5 cm on supine sonography. The difference between clock positions and the distances from the nipple on upright versus supine sonography were statistically significant. Therefore, upright sonography is more accurate in localizing mammographically identified lesions than the standard supine sonographic technique.