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THE EFFECT OF BODY WALL ON VIDEO SIGNAL ANALYSIS MEASUREMENTS
Author(s) -
Waller Kenneth R.,
Knipp Brian S.,
O'Brien Robert T.,
Zagzebski James A.
Publication year - 2003
Publication title -
veterinary radiology and ultrasound
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.541
H-Index - 60
eISSN - 1740-8261
pISSN - 1058-8183
DOI - 10.1111/j.1740-8261.2003.tb01275.x
Subject(s) - imaging phantom , attenuation , echogenicity , medicine , ultrasound , nuclear medicine , biomedical engineering , attenuation coefficient , beagle , anatomy , optics , radiology , physics
Rectangular body wall specimens were extracted from 16 juvenile swine and 9 adult beagle hounds after euthanasia. The body wall specimen included the epidermis to parietal membrane, with falciform fat removed. Ten images of a reference phantom with known attenuation and 10 additional images of the phantom with the specimen placed between the transducer and phantom surface were collected with a 5‐MHz ultrasound system and computer with frame grabber board. Mean pixel values were converted to relative echogenicities. Echogenicity versus depth yielded an estimate of attenuation. An unpaired t test was applied to compare reference attenuation values with and without body wall, and a Pearson correlation was applied to body Wall parameters versus measured attenuation through body wall. Measured attenuation through body wall increased significantly in dogs ( P = 0.0016) and swine ( P < 0.0001) when compared with phantom material alone. Increased attenuation positively correlated to body wall thickness ( r = 0.6442) and mean gray level within body wall ( r = 0.5069) for swine but not in canine. The presence of body wall in images used for video signal analysis significantly increases the measured attenuation in a phantom. This increase does not correlate with a measurable body wall parameter in dogs.