title: Comparison of radiographic texture analysis from computed radiography and bone densitometry systems.
abstract: Osteoporosis is a disease that results in an increased risk of bone fracture due to a loss of bone mass and deterioration of bone structure. Bone mineral density (BMD) provides a measure of bone mass and is frequently measured by bone densitometry systems to diagnose osteoporosis. In addition, computerized radiographic texture analysis (RTA) is currently being investigated as a measure of bone structure and as an additional diagnostic predictor of osteoporosis. In this study, we assessed the ability of a peripheral bone densitometry (PD) system to yield images useful for RTA. The benefit of such a system is that it measures BMD by dual-energy x-ray absorptiometry and therefore provides high- and low-energy digital radiographic images. The bone densitometry system investigated was the GE/Lunar PIXI, which provides 512 x 512 digital images of the heel or forearm (0.2 mm pixels). We compared texture features of heel images obtained with this PD system to those obtained on a Fuji computed radiography (CR) system (0.1 mm pixels). Fourier and fractal-based texture features of images from 24 subjects who had both CR and BMD exams were calculated, and correlation between the two systems was analyzed. Fourier-based texture features characterize the magnitude, frequency content, and orientation of the trabecular bone pattern. Good correlation was found between the two modalities for the first moment (FMP) with r=0.71 (p value<0.0001) and for minimum FMP with r=0.52 (p value=0.008). Root-mean-square (RMS) did not correlate with r=0.31 (p value>0.05), while the standard deviation of the RMS did correlate with r=0.79 (p value<0.0001). Good correlation was also found between the two modalities for the fractal-based texture features with r=0.79 (p value<0.0001) for the global Minkowski dimension and r=0.63 (p value=0.0007) for the fractal dimension from a box counting method. The PD system therefore may have the potential for yielding heel images suitable for RTA.
authors.affiliation: Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637, USA.
authors.forename: Joel R
authors.initials: JR
authors.lastname: Wilkie
authors.forename: Maryellen L
authors.initials: ML
authors.lastname: Giger
authors.forename: Michael R
authors.initials: MR
authors.lastname: Chinander
authors.forename: Tamara J
authors.initials: TJ
authors.lastname: Vokes
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Larry
authors.initials: L
authors.lastname: Dixon
authors.forename: Vit
authors.initials: V
authors.lastname: Jaros
mesh_terms: D015502:Absorptiometry, Photon / Q000295:instrumentation* / Q000379:methods; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D002111:Calcaneus / Q000000981:diagnostic imaging; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D011856:Radiographic Image Enhancement / Q000295:instrumentation* / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods