Clinical evaluation of a high-resolution new peripheral quantitative computerized tomography (pQCT) scanner for the bone densitometry at the lower limbs

• Published in: Physics in medicine & biology Vol. 43; no. 8; pp. 2279 - 2294
• Main Authors: Braun, M J, Meta, M D, Schneider, P, Reiners, Chr
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.08.1998; Institute of Physics
• Subjects: Biological and medical sciences; Bone Density; Femur - diagnostic imaging; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Osteoarticular system. Muscles; Phantoms, Imaging; Quality Assurance, Health Care; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Reproducibility of Results; Sensitivity and Specificity; Software; Tibia - diagnostic imaging; Tomography, X-Ray Computed - instrumentation; Tomography, X-Ray Computed - methods; Tomography, X-Ray Computed - standards; Performance evaluation; Human; High resolution; Error analysis; Radiodiagnosis; Lower limb; Osteoarticular system; In vivo; Accuracy; Medical imagery; Computerized axial tomography; Effective dose; Quantitative analysis
• ISSN: 0031-9155; 1361-6560
• DOI: 10.1088/0031-9155/43/8/020

Precision, long-term stability, linearity and accuracy of the x-ray peripheral quantitative computerized tomographic (pQCT) bone scanner XCT 3000 (Norland-Stratec Medical Sys.) were evaluated using the European Forearm Phantom (EFP). In vivo measurements were assessed using a standardized procedure at the distal femur and the distal tibia. In the patient-scan mode, the spatial resolution of the system was 1.04 +/- 0.05 lp/mm as measured at the 10% level of the modulation transfer function (MTF). The contrast-detail diagram (CDD) yielded a minimal difference in attenuation coefficient (AC) of 0.07 cm(-1) at an object size of 0.5 mm. The effective dose for humans was calculated to be less than 1.5 microSv per scan. Short-term precision in vivo was expressed as root mean square standard deviation of paired measurements of 20 healthy volunteers (RMSSD = 0.5%). At the distal femur total volumetric density (ToD) and total cross-sectional area (ToA) were found to be less sensitive to positioning errors than at the distal tibia. Structural parameters like the polar cross-sectional moment of inertia (CSMIp) or the polar cross-sectional moment of resistance (CSMRp) showed a good short-term precision at the distal femur (RMSSD = 1.2 and 1.4%). The relation between the two skeletal sites with respect to CSMIp or CSMRp showed a high coefficient of determination (r2 = 0.77 and 0.74).