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Generalized SDNR analysis based on signal and noise power.

Generalized SDNR analysis based on signal and noise power.

Authors :
Monnin P
Gnesin S
Verdun FR
Marshall NW
Source :
Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB) [Phys Med] 2019 Aug; Vol. 64, pp. 10-15. Date of Electronic Publication: 2019 Jun 19.
Publication Year :
2019

Abstract

The standard approach to signal difference-to-noise ratio (SDNR) analysis requires a region of interest (ROI) positioned within the object to measure signal-difference, restricting this metric to flat-topped objects with large, sharply delineated areas. This work develops a generalized expression for SDNR (SDNR <subscript>g</subscript> ) calculated from a ROI encompassing the object. Signal power, defined as the deviation of pixel values from the mean background due to the object, is used instead of signal-difference. Comparison was first made by simulating ideal flat-topped discs with sharp edges and diameters between 1 and 80 pixels, into a uniformly noisy background using a known signal-difference. For discs covering more than 20 pixels, SDNR <subscript>g</subscript> and standard SDNR (SDNR <subscript>st</subscript> ) were within 3%, while for discs of less than 20 pixels, SDNR <subscript>g</subscript> was within 26% of the truth compared to 58% for SDNR <subscript>st</subscript> . Generalized and standard SDNR were compared for radiography images of three different phantoms with microcalcification-like objects (MTM-100 phantom), hemispheric objects of different thicknesses with a Gaussian intensity distribution and mammography quality control (QC) images. Applied to Gaussian details, SDNR <subscript>g</subscript> was between 20% and 45% higher than SDNR <subscript>st</subscript> , depending on object thickness, while for the QC images, SDNR <subscript>g</subscript> was with 1.7% of the standard SDNR. Compared to the standard SDNR, SDNR <subscript>g</subscript> is applicable to non-uniform signals, where an explicit contrast measurement is not suitable, and has improved accuracy when assessing SDNR of small objects.<br /> (Copyright © 2019 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

Details

Language :
English
ISSN :
1724-191X
Volume :
64
Database :
MEDLINE
Journal :
Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)
Publication Type :
Academic Journal
Accession number :
31515008
Full Text :
https://doi.org/10.1016/j.ejmp.2019.06.005