Gray scale range and the marking of vertebral coordinates on digitized radiographic images.
OBJECTIVE
To determine the relationship between X-ray image quality as reflected by the gray scale range and the reliability of measuring intervertebral angles.


METHODS
Intrarater reliability evaluation.


METHODS
Image processing laboratory.


METHODS
Digitized images of fluoroscopic AP lumbar motion sequences obtained from eight patients.


METHODS
Ten consecutive measurements of a single intervertebral angle in each subject related to gray scale range and midpoint gray level. The results were compared to measurements from an osseous lumbar spine calibration model.


METHODS
Variance of intervertebral angles in relation to gray scale range and midpoint level.


RESULTS
No relationship was found between reliability of intervertebral angles and image parameters.


CONCLUSIONS
For radiographs of diagnostic quality the gray scale range and midpoint level over the area of interest does not affect the reliability of coordinate marking.
Anglo-European College of Chiropractic, Bournemouth, England.
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Thorkeldsen
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AC
Breen
D000328:Adult; D005471:Fluoroscopy; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D015588:Observer Variation; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results