Standardizing evaluation of pQCT image quality in the presence of subject movement: qualitative versus quantitative assessment.
Peripheral quantitative computed tomography (pQCT) is an essential tool for assessing bone parameters of the limbs, but subject movement and its impact on image quality remains a challenge to manage. The current approach to determine image viability is by visual inspection, but pQCT lacks a quantitative evaluation. Therefore, the aims of this study were to (1) examine the reliability of a qualitative visual inspection scale and (2) establish a quantitative motion assessment methodology. Scans were performed on 506 healthy girls (9-13 years) at diaphyseal regions of the femur and tibia. Scans were rated for movement independently by three technicians using a linear, nominal scale. Quantitatively, a ratio of movement to limb size (%Move) provided a measure of movement artifact. A repeat-scan subsample (n = 46) was examined to determine %Move's impact on bone parameters. Agreement between measurers was strong (intraclass correlation coefficient = 0.732 for tibia, 0.812 for femur), but greater variability was observed in scans rated 3 or 4, the delineation between repeat and no repeat. The quantitative approach found ≥95% of subjects had %Move <25 %. Comparison of initial and repeat scans by groups above and below 25% initial movement showed significant differences in the >25 % grouping. A pQCT visual inspection scale can be a reliable metric of image quality, but technicians may periodically mischaracterize subject motion. The presented quantitative methodology yields more consistent movement assessment and could unify procedure across laboratories. Data suggest a delineation of 25% movement for determining whether a diaphyseal scan is viable or requires repeat.
Robert M
RM
Blew
Vinson R
VR
Lee
Joshua N
JN
Farr
Daniel J
DJ
Schiferl
Scott B
SB
Going
D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000592:standards*; D009068:Movement / Q000502:physiology*; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D013977:Tibia / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000592:standards*