1. Wednesday Case of the Day
Physics
Authors: Raja Subramaniam, Ph.D., Laurie Margolies, M.D.
Icahn School of Medicine at Mount Sinai Medical Center, New York, NY
History Shown here are the 2D FFDM image and C-view synthesized image for the same patient. A streak artifact as indicated is seen in the 2D FFDM image. The artifact is missing in the synthesized image. What is the artifact due to? Why is it not seen in the synthesized image?
Patient motion
Foreign object on the paddle
Focal spot artifact
Image processing artifact
FFDM
C-VIEW

2. Diagnosis Correct Answer: B - Patient’s Hair is the cause of Artifact in the 2D-FFDM image.
C-VIEW

3. Discussion
Tomosynthesis displays several slices equal to the measured thickness of the breast plus a few extra processing slices. For example, if the measured thickness was 42 mm there would be 42 slices + 4 or 5 more. Thickness is calculated by the area between the bottom of the paddle (pink) and the top of the detector (white) during compression. 
C-view and tomosynthesis images would display the content between the detector and the paddle i.e the breast tissue (beige) and not display any area above the paddle. 
Therefore, hair would be visible on a FFDM image, but not on C-view (nor on tomosynthesis).
In this schematic, green is the patient’s hair.

4. References/Bibliography:
1. Choi JJ, Kim SH, Kang BJ, Choi BG, Song B, Jung H. Mammographic Artifacts on Full-Field Digital Mammography. Journal of Digital Imaging. 2014; 27(2) :
2. Quality assurance in mammography: artifact analysis.
Hogge JP, Palmer CH, Muller CC, Little ST, Smith DC, Fatouros PP, de Paredes ES. Radiographics Mar-Apr;19(2): Review.
3. Gold, BM, American Journal of Roentgonology, Aug;159(2):430.