Using Maximum Intensity Projection in the Evaluation of Digital Breast Tomosynthesis: A Phantom Observer Study From the American College of Radiology Imaging Network PA 4006 Trial
M Thomas*, Y Matsutani, E Conant, A Maidment, Univ Pennsylvania, Philadelphia, PASU-C-116-5 Sunday 1:00PM - 1:55PM Room: 116
Purpose: Characterize the effect of slice level and maximal intensity projection (MIP) slab thickness on image quality in digital breast tomosynthesis (DBT).
Methods:Eight ACRIN 4006 PA DBT acquisitions of the ACR Mammography Accreditation Phantom were selected from the Hospital of the University of Pennsylvania (n=4) and Einstein Medical Center, Philadelphia, PA (n=4). An experienced medical physicist scored each phantom by first recording scores at single slice levels in increments of increasing depth to confirm the score for each level. Scoring was next repeated with a 40-mm MIP by identical method. MIP thickness was then decreased in 10-mm increments and scored again. If a difference in score occurred between 10-mm MIP slab thickness differences, objects were rescored at the intermediate 5-mm MIP slab thickness, and so forth.
Results:Fiber, speck and mass scores are all sensitive to slice level (single slice) or central slice level (MIP). Specks are the most sensitive. Scores can change substantially if slice level is shifted by one slice when viewing single slices or MIP slabs which are less than 10 mm thick. Scores of fibers and masses decrease with increasing MIP slab thickness, while speck scores do not change substantially. Even when all objects are ostensibly in the MIP volume, their location in the volume affects the score. Scores are degraded when the objects are nearer the top or bottom slice of the MIP slab.
Conclusion:In single slice review, slice level substantially affects phantom score, thus care in slice selection is necessary. Increasing MIP slab thickness does not appear to substantially degrade image quality of specks, supporting the clinical practice of using MIP in the review of calcifications. MIP review of phantoms may add value in visualizing artifacts outside the plane of review.