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Bone Density Measurement. Normal. Osteoporosis. Chalermchai Apinyanurug. Densitometry Technologies. Central BMD Measurements QCT DEXA Peripheral BMD Measurements Conventional X-ray RA – radiographic absorptiometry X-Ray Radiogrammetry Ultrasonometry Peripheral DEXA.
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Bone Density Measurement Normal Osteoporosis Chalermchai Apinyanurug
Densitometry Technologies Central BMD Measurements • QCT • DEXA Peripheral BMD Measurements • Conventional X-ray • RA – radiographic absorptiometry • X-Ray Radiogrammetry • Ultrasonometry • Peripheral DEXA
Routine radiographic • Low Radiation dose • Insensitive: bone loss is apparent only after a 30% loss
Radiographic Absorptiometry • Measures the optical density • fingers only • small, inexpensive • poor hip fracture prediction
Radiogrammetry • Width of cortical bone in fingers using standard x-ray • Can be added to existing mammo / x-ray system (need computer and scanner) • fingers only • poor hip fracture prediction
QCT : Quantitative CT • High radiation dose • Less precise than DXA (2-5%) • Large accuracy errors (15%) • Expensive
QUS • High frequency ultrasound • Assess fracture risk • Predicts hip fracture • Portable, small, economical • Monitor therapy • Radiation free
What’s new in DXA equipment's? New Detector : Direct-Digital Cadmium Zinc Telluride (CZT)Better image qualityLow X-ray exposureHigh accuracy and precision
New Asian Reference Database • BMD by DXA • Body composition • QUS pediatric • China • Korea • Indonesia • Japan • Thai
New software : Computer Assisted Densitometry • Automatic verification • Positioning • Bone edges • Analysis regions • Artifacts • Abnormal BMD • Clinical Benefits • Reduce errors • Better scan evaluation
New technique : One Positioning One Position, Three Scans: AP Spine, Left Femur and Right Femur
New Report • BMD results • Previous results • Reference Data Comparison • Trending to past values • Bone strength assessments • Hip Axis Length • Femur Strength Index
New Hip Assessment • Hip Axis Length • Upper Neck • Femur Geometry • Dual femur study • Femur Strength Index A Better Way to Look at the Femur Osteoporosis International January, 2006
Femur Strength Index • 2,506 women. > 50 yr. • HAL & FSI : significant predictors of hip fracture • Power for predicting fracture was significantly improved by combining T-score, FSI, and HAL compared with T-score alone. Osteoporosis International January, 2006
Dual Femur study : Improved Diagnosis and Treatment Decisions American Society for Bone andMineral Research : ASBMR 2005
Air Displacement Near Infrared Interactance Body Composition Methods Anthropometry Underwater Weighing (Hydrodensitometry) DXA (Dual-energy X-Ray Absorptiometry) Imaging Methods (CT, MRI) BIS BIA (Bioelectrical Impedance Analysis)
Body Composition with DXA • Directly measures fat, lean, and bone mass • Monitoring impact of treatment and exercise/diet regimens. • Too much body fat, high rates of diseases such as obesity, diabetes, cancers, heart disease, and high blood pressure”
Body Composition and Cardiovascular Disease • Android/Gynoid Ratio identifies women with cardiovascular disease • Overweight women: healthy vs. diagnosed with cardio-vascular disease • Better than cholesterol, better than triglycerides Ragi et al. ASBMR 2005
Estimated Total Body % Fat from Spine and Femur Scans ASBMR 2005