Dr.Juan A.Venter Dept. Clinical Imaging Sciences Bloemfontein Academic Hospitals 18/05/2012

 Most common of all metabolic bone disorders  Significant morbidity(50% for hip fractures) and mortality(20% for hip fractures in 1 year)  Treatment cost in Europe : 75 billion Euros by  Lifetime Osteoporotic Fracture Risk(Caucasian) Woman- 40% Men - 20%  Preventive therapies available.

 Systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue with a consequent increase in bone fragility and susceptibility to fracture which usually involves the wrist,spine, hip, pelvis,ribs or humerus.

 Detect osteoporosis - (Fragility) fractures  Quantification -Measure bone mass : Semiquantitative(Conventional Radiography) Quantitative (Bone Mass Densitometry)  Morphometry : Radiogrammetry Singh Index Vertebral Morphometry  Bone Mineral Densitometry(BMD) : DXA (Dual energy X – ray absorptiometry) - Axial/Peripheral QCT (Quantitative CT – Axial/Peripheral),HRCT Other – QUS,QMR

 Increased Radiolucency/Cortical Thinning  Notoriously inaccurate : 30 – 40 % loss of bone mass need to be present before detection  25 % of apparent osteopenia on radiography (technical faults) or vertebral fractures(juvenile epiphysitis,normal variants,trauma) have normal BMD  Can detect osteomalacia/hyperparathyroidism  Loss of at least 20% or 4 mm vertebral body height required for diagnosis of vertebral fracture – increase risk of subsequent fractures of vertebrae x 2 and hip x 5

 Not pain free within 6-8 weeks  Non Anterior Wedge  Posterior Wedge(other than L4+5)  Above T7  Concave posterior vertebral border is more likely a sign of benign osteoporotic fracture, whereas a convex posterior border suggests malignant disease. Consider : Neoplastic disease – multiple myeloma/metastases Osteomalacia Schauermans disease(Juvenile epiphysistis) Trauma Degeneration MR imaging findings of malignant disease include multiple contrast enhancing lesions or soft-tissue masses, with or without encasing epidural masses and destructive changes

 Rapid scanning  Precise results if performed meticulously  Extreme low doses of radiation  Vertebral assessement from lateral images obtained on fan beam DXA system can be done at 1/100 th of dose of conventional radiography.  Central/Peripheral DXA

 Calibrated at least 1/week  Meassurement monoplanar – g/cm2 and therefor size dependant (children)  All calcium in path of electron beam contributes to BMD(Aortic calcifications degenerative/hyperostotic changes/vertebral wedging,metallic pinning) with overestimation of BMD.Exclude these areas from analysis/Lateral scanning  Strontium ranelate treatment – artefactual increase in BMD  Results of different scanners not interchangeable

 Need appropriate race and sex matched BMD reference ranges – ethnic differences in BMD and fracture prevelance  Expressed as standard deviation from : Age matched – Z Score Peak bone mass – T Score Normal - > – 1 sd Osteopenia - – 2.5 sd Osteoporosis - < -2.5 sd Severe Osteoporosis - fragility fractures

 Woman > 65 years and men > 70 years  Radiographic evidence of osteoporotic vertebral fractures or apparent osteopenia  History of fragility fractures after age 40  Known causes of secondary osteoporosis : Early menopause(< 45 years of age) / hypo gonadism in men/woman Systemic diseases with adverse effect on bone Bone toxic drugs

 Facilitate desicions regarding initiation/ discontinuation of drug therapy (biphosphonates /HRT)  Strong clinical risk factors: Family history of hip fractures or osteoporosis BMI < 19 kg/m2 Regular C2H5OH intake(>3 drinks/day) Smoking Poor nutrition /Calcium intake/Vitamin D exposure

 Low specificity – < 50 % of known osteoporotic fractures have BMD in osteoporotic range(T < - 2.5)  Other risk factors like propensity to falls or qualitative risk factors like bone turnover not included  Extrapolation to other populations measured at different skeletal sites with other techniques (QUS,QCT) not acceptable.  Other metabolic bone diseases  Intervention threshold applicable to all

 Confirm diagnosis with BMD or presence of fragility fracture before initiation of treatment with bone active drugs.  Axial BMD to be used to diagnose and access rate of bone loss/gain. QCT/QUS not recommended and results cannot be applied to T score based WHO diagnostic classification  Lowest BMD value measured at spine,total femur and femur neck(or distal radius if invalid)  Express results for post menopausal Caucasian woman as T scores and Z scores for pre menopausal woman and men < 50 year  Men over 50 years : Employ female reference data to determine T score  Local black population : use reference data for Caucasian females for all subjects of all races until local reference values become available.

 Children:Low BMD + significant fracture history  Follow up scans every months or earlier in GIOP  Search for evidence of vertebral compression fractures in all who qualify for BMD measurement – Standard x-ray and use modified Genant semiquintative system to grade (Gr.1-3) Higher grade = higher risk for subsequent fractures of hip and vertebrae or DXA VFA.

 Considered treatment after prior fragility fracture(wrist, spine,hip,pelvis,rib,humerus) regardles of BMD value  Considered treatment if DXA T Score < -2.5 at hip or spine  Considered treatment if DXA T score (osteopenia) if significant clinical risk factors.  BMD measured on all patients on long term glucocorticosteroids(50% develop GIOP regardless of dose)-start treatment if T Score <  Biphophonates – 1 st line preventative therapy and anabolics reserved for advanced disease

 Reduce the high subjectivity and poor reproducibility of qualitative readings  Vertebral fractures are one of the most important CRF – 60% asymptomatic and go undetected if not routinely searched for  Visualize lateral spine on DXA with VFA software  Lower radiation dose and cost compared to conventional radiography  Conventional radiography remain gold standard – often only requested if fracture is suspected

 Separate estimation of cortical and trabecular bone  True volumetric density – g/cm3 making it non size dependant (children/small stature)  Performed with calibration reference phantom to transform HU into BMD equivalents  Radiation dose compares favourably with conventional radiography  Excellent for predicting vertebral fractures and serially measuring bone loss - selectively assesses the metabolically active and structurally trabecular bone  Increase in marrow fat is age related, single-energy CT data can be corrected with use of age-related reference databases

 Can be used to detect differences in trabecular structure depending on patient age, BMD, and osteoporotic status  Most often performed at peripheral sites such as the calcaneus, knee, and wrist.  Substantial improvement in fracture discrimination made possible by considering structural information as well as BMD  May replace biopsy when this would be advocated.

 - accessed 28/04/  Grainger and Allison’s Diagnostic Radiology A Textbook of Medical Imaging,5 th Edition  Orthopedic Imaging A Practical Approach Adam Greenspan,5 th Edition  Radiographics : September – October 2011 Integrated Imaging Approach to Osteoporosis: State-of-the-Art Review and Update