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Proceedings Paper

Comparison of analog and digital magnification in x-ray fluoroscopy image sequences
Author(s): Yogesh Srinivas; David L. Wilson
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Paper Abstract

Radiologists resort to image magnification in x-ray fluoroscopy to better visualize small interventional devices. Image intensifier (II) systems use analog magnification with x-ray exposure inversely proportional to the area of field of view (FOV) so as to maintain light output for the camera. Flat-panel (FP) detector images can only be magnified using digital interpolation. We quantitatively investigated image quality of digital and analog magnification using a task of detecting a partially deployed stent in simulated x-ray fluoroscopy image sequences. Exposure for FP magnification was varied in an adaptive forced choice experiment so as to match performance with II magnification. II exposure was set at a nominal value of 5.0 (mu) R per frame at 23 cm FOV and using the standard exposure strategy, increased to 9.15 and 13.49 (mu) R per frame at 17 and 14 cm FOV, respectively. Image quality improved 1.44 +/- 0.065 and 1.64 +/- 0.073 times by going to the 17 and 14 cm FOV, respectively. For equivalent image quality, FP required 4.00 +/- 0.30, 9.50 +/- 0.62, and 9.85 +/- 0.64 (mu) R per frame at normal, mag-1 and mag-2, respectively. As compared to II, FP gives significant dose savings of 20 +/- 6% and 27 +/- 5% at the normal and highest magnification modes, respectively. A human-observer model describes results and can be used to predict results for similar acquisition and processing methods.

Paper Details

Date Published: 12 April 2002
PDF: 10 pages
Proc. SPIE 4686, Medical Imaging 2002: Image Perception, Observer Performance, and Technology Assessment, (12 April 2002); doi: 10.1117/12.462670
Show Author Affiliations
Yogesh Srinivas, Case Western Reserve Univ. (United States)
David L. Wilson, Case Western Reserve Univ. (United States)

Published in SPIE Proceedings Vol. 4686:
Medical Imaging 2002: Image Perception, Observer Performance, and Technology Assessment
Dev Prasad Chakraborty; Elizabeth A. Krupinski, Editor(s)

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