Understand depth and distance from nipple.

A quick and easily reproducible method for reporting the location of a lesion in a mammogram is essential for the radiologist.

Depth: The breast is split into three layers of depth: anterior, middle, and posterior with each depth category representing approximately one-third of the breast tissue. These thirds are called A=anterior or the superficial third; B=middle third; C=posterior or the deep third (chest wall) of the breast.

Distance: There are five general locations for distance from the nipple: 1, 2, 3, subareolar (SA), and axillary (A). The numbers 1, 2, and 3, define equal-width rings extending from the areola area to the periphery of the breast. The ring labeled 1 is the most central, and the ring labeled 3 is the most peripheral. A more commonly used way to describe the distance from the nipple is to measure centimeters from the nipple (CMFN), which you can learn about under lesson three titled Centimeters from the nipple.

The method for describing the location is essential for two reasons. First, it is reproducible and helps us find a lesion easily for follow-up studies or procedures. Second, it represents an easy-to-type, shorthand method for annotating a lesion location while scanning the patient with ultrasound.

In the American Institute of Ultrasound in Medicine and ACR accreditation programs, the following descriptors are mandatory in ultrasound images: the side (right or left), the clock face position, the distance from the nipple (CM FM for ultrasound), and the scan plane, which is Radial (rad) and Anti-radial (ar).