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Comparison of full‐field digital mammography to screen‐film mammography with respect to contrast and spatial resolution in tissue equivalent breast phantoms
Author(s) -
Kuzmiak Cherie M.,
Pisano Etta D.,
Cole Elodia B.,
Zeng Donglin,
Burns Charles B.,
Roberto Craig,
Pavic Dag,
Lee Yeonhee,
Seo Bo Kyoung,
Koomen Marcia,
Washburn David
Publication year - 2005
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2040710
Subject(s) - mammography , digital mammography , imaging phantom , scanner , image resolution , nuclear medicine , contrast (vision) , medicine , medical physics , computer science , physics , optics , breast cancer , cancer
To determine if the improved contrast resolution of full‐field digital mammography (FFDM) with reduced spatial resolution allows for superior or equal phantom object detection compared with screen‐film mammography (SFM). Tissue equivalent breast phantoms simulating an adipose to glandular ratio of 50 ∕ 50 , 30 ∕ 70 , and 20 ∕ 80 were imaged according to each manufacturers’ recommendation with four full‐field digital mammography units (Fuji, Sectra, Fischer, and General Electric) and a screen‐film mammography unit (MammoMatII 2000, Siemens, Munich, Germany). A total of 20 images were obtained in both hard‐ and soft‐copy formats. For the purpose of soft‐copy display, the screen‐film hard‐copy images were digitized with a 50 μ m micron scanner. Six radiologists, experts in breast imaging, and three physicists, experts in scoring mammography phantoms, participated in a reader study where each reader scored each phantom for visibility of line‐pairs and for 24 objects (fibers, clusters of specks, and masses). The data were recorded, entered into a database, and analyzed by a mixed‐effect model. The limiting spatial resolution in line‐pairs per millimeter visible with the digital units was less, regardless of display modality used, than that provided by the screen‐film unit. The difference was statistically significant for the General Electric ( p < 0.01 ) and Fuji digital mammography units ( p = 0.03 ) . With respect to the number of visible objects, a statistically significant higher number could be detected with the screen‐film unit as compared to the Fischer ( p < 0.01 ) and Sectra ( p < 0.01 ) digital mammography units, but there was no significant difference between the other digital units and screen film. Overall, there was significantly better performance on the 50 ∕ 50 phantom than with the 30 ∕ 70 and 20 ∕ 80 phantoms ( p = 0.01 , p < 0.01 ) for object visibility. For the digital mammography units, soft‐copy display performed better than hard‐copy display for the Fischer and Sectra images, but worse for Fuji and General Electric. In addition, soft‐copy display of digitized screen‐film images was significantly better than hard‐copy display ( p = 0.02 ) of the original screen films for object visibility, but worse for spatial resolution. The higher contrast resolution of the FFDM units tested did not result in improved detection of line‐pair resolution or objects in the phantoms tested versus screen‐filmmammography. The phantom performance of a digital mammography unit seems to be influenced by the type of detection task (line‐pair resolution versus object visibility), the display modality (soft‐copy versus hard‐copy) chosen to score the phantoms, and the parenchymal pattern composition of the phantom.