Diagnostic Imaging Pathways - Osteoporosis (Suspected)

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Population Covered By The Guidance

This pathway provides guidance on the imaging of adult patients with suspected osteoporosis.

Date reviewed: December 2014

Date of next review: 2017/2018

Published: March 2015

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SYMBOL RRL EFFECTIVE DOSE RANGE
No radiation None 0
Minimal radiation Minimal < 1 millisieverts
Low radiation Low 1-5 mSv
Medium radiation Medium 5-10 mSv
High radiation High >10 mSv

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Pathway Diagram

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Image Gallery


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1a Click to view full size image

Osteoporosis

Image 1a (DEXA scan): The left hip bone mineral density measures 0.785 gm/cm^2. This correlates with a 'T' score of -2.2, and a 'Z' score of -1.6.

1b Click to view full size image

Image 1b (DEXA scan): The lumbar spine bone mineral density measures 0.781 gm/cm^2. This correlates with a 'T' score of -2.8 and a 'Z' score of -2.5.

Based on the WHO Diagnostic Categories for Osteoporosis, the lowest T score of -2.8 in the lumbar spine indicates osteoporosis.

2 Click to view full size image

Complications of osteoporosis

Image 2 (Lumbar spine radiograph): Multiple vertebral crush fractures on a background of severe osteoporosis.

3 Click to view full size image

Complications of osteoporosis

Image 3 (Pelvis radiograph): AP view of a comminuted inter-trochanteric fracture of the left hip.

4 Click to view full size image

Complications of osteoporosis

Image 4 (Pelvis radiograph): AP view of an impacted sub-capital right hip fracture.

5 Click to view full size image

Complications of osteoporosis

Image 5 (Wrist radiograph): Impacted fracture of the distal left radius.

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Teaching Points

  • Osteoporosis is characterised by low bone mass and micro architectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in the risk of fracture
  • It is an important public health issue that is often under-recognised in the community until a disabling fracture occurs
  • There are several indications for testing of bone mineral density, as a surrogate marker of osteoporosis
  • DEXA is currently the favoured modality for determining bone mineral density
  • The World Health Organisation has developed strict criteria that determines eligibility for osteoporotic treatment
  • Several pharmacological treatments are available that effectively treat osteoporosis and prevent further loss of bone density
  • In patients with established osteoporosis, the institution of an appropriate anti-osteoporotic pharmaceutical regime reduces subsequent fracture risk by 50 percent and also reduces premature mortality 19

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Osteoporosis

  • Osteoporosis is characterised by low bone mass and micro architectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in the risk of fracture 1
  • The World Health Organization (WHO) has designated the first decade of the 21st century, as the 'Decade of Bone and Joint Diseases' recognising the importance of osteoporosis as a public health issue 2
  • The cost to Australian economy of osteoporosis is estimated to be $7.4 billion dollars per year 4
  • Osteoporosis is often described as a 'silent disease', with the radiological prevalence of the disease far in excess of diagnosis and active treatment to prevent further bone loss and future fracture 4
  • Risk factors associated with osteoporosis 1
    • Family history - parent or sibling
    • Early menopause
    • Hypogonadism
    • ≥3 months glucocorticoids (at prednisolone ≥7.5mg)
    • Coeliac disease / malabsorption disorders
    • Rheumatoid arthritis
    • Primary hyperparathyroidism
    • Hyperthyroidism
    • Chronic kidney or liver disease
    • Androgen deprivation therapy
    • Recurrent falls
    • Breast cancer on aromatase inhibitors
    • Treatment with antiepileptic medications
    • Low body weight
    • HIV and its treatment
    • Major depression / SSRI treatment
    • Type 1 and type 2 diabetes mellitus
    • Multiple myeloma / monoclonal gammopathy
    • Organ or bone marrow transplant
  • There are various fracture risk calculators in existence. In Australia a locally developed calculator based on the Dubbo Osteoporosis Epidemiology Study 18 can be found by following this link. Another commonly used tool is the Fracture Risk Assessment Tool (FRAX) which has been developed by WHO. The calculator for this can be found by following this link. The Garvan tool has been shown to be more accurate than the FRAX tool 19
  • At any age, women are considered to have approximately double the risk of a fracture compared with men. However once a man sustains a fragility fracture his risk of a subsequent fracture is higher than that of an equivalent woman 19
  • For T scores of -1.0, -2.0 and -3.0 the relative risk of fracture increases by a factor of 1.7, 3.4 and 6.8 respectively 20

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Dual-Energy X-Ray Absorptiometry (DEXA) Scan

  • The current "gold standard" for the diagnosis of osteoporosis 1,20
  • DEXA is superior to other techniques for assessing BMD because of its 9,20
    • Low precision error
    • Low radiation dose and short scan time (approximately one-tenth of that of a standard chest radiograph)
    • Capacity to measure multiple skeletal sites
  • Limitations of DEXA include 1
    • Hip replacement precludes measurement of hip BMD
    • In the spine, degenerative disease cause falsely elevated results owing to features such as osteophytes and compression fractures
    • Measurements of different DEXA machines may vary considerably for the same individual (it is important to have follow-up scans on the same machine if possible)
  • Results are expressed as Z or T scores, defined as the number of standard deviations (SDs) from the age and sex matched control means (Z score) and from the mean value in a 30 year old (T score) 1
  • The T score can be expressed as the following 21

  • Measured BMD – Young adult mean BMP
    —————————————————
    Young adult population SD
     
  • When interpreting serial DEXA scans it is best to consider the bone density change over time (g/cm2) rather than T scores as T score calculations are age dependent 20
  • Based on bone densitometry, measured by DEXA and the T score, the World Health Organization classifies the patients into three categories 6,7
    • Normal bone density: T score greater than -1
    • Osteopenia (low bone mass): T score between -1 and -2.5
    • Osteoporosis: T score less than -2.5
  • For information for consumers about DEXA InsideRadiology

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Further Radiological Investigations in the Assessment of Bone Mineral Density

Peripheral DEXA - The use of these devices is increasing due to their ease of use and portability. However individual manufacturers have established their own guidelines that have not been validated in the assessment of bone mineral density in large randomised trials 16


Spinal Quantitative Computed Tomography (QCT) - QCT is the most accurate tool to measure bone density, being 2-3 times more sensitive than DEXA in detecting loss of bone mineral. It is the only technique allowing volumetric measurement of the trabecular interior of bone. A major clinical limitation is the radiation exposure when compared to DEXA, as well as cost and resources availability issues 17


Quantitative Ultrasound (QUS) - Several large prospective cohort studies have clearly demonstrated that this modality can predict future fracture risk. 12,13 There are several potential advantages over DEXA including expense, portability and lack of ionizing radiation. However a recent large meta-analysis found the sensitivity and specificity of calcaneal ultrasound low when compared to DEXA as the standard reference. 14 Furthermore cost-effective analysis utilising QUS as a pre-screening tool prior to DEXA in postmenopausal women has failed to show a benefit 15


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Indications for DEXA

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Conservative Management

  • The following points should be addressed in those patients who do not have an indication for DEXA scan or whose scan result does not qualify them for osteoporotic treatment
    • General lifestyle advice
    • Advise to stop smoking and consume minimal alcohol
    • Evaluate and rectify possible causes of falls
    • Advocate a regular weight bearing or strengthening exercise program
    • Exposure to indirect sunlight for 15 minutes, four to six times a week
  • Ongoing monitoring for osteopenia/osteoporosis. Regularly monitor height as a loss of height of 2.5cm is a surrogate marker for osteoporosis. Plain radiographs of the spine should be considered for an asymptomatic vertebral fracture 10

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Osteoporosis Treatment

The general principles of treatment in osteoporosis centre around the following 19

  • Address and correct any underlying conditions that may be contributing to the development and progression of osteoporosis (e.g. hypogonadism, myeloma, hyperparathyroidism, Cushing’s syndrome, etc)
  • Despite limited evidence there should be a consideration of lifestyle aspects (e.g. encouraging weight exercise, dietary intake of calcium, cease smoking, evaluate and rectify possible causes of falls, etc)
  • Osteoporosis specific pharmacotherapy
  • Vitamin D and calcium supplementation if inadequate
  • Falls prevention strategies

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Osteoporosis Follow Up

The following table contains recommended management and follow up depending on the BMD T score, risk factors and presence or absence of a minimal trauma fracture 1


T Score
Minimal Trauma Fracture
Risk Factors
Management / Recommendation

≤ -2.5

Present

One or more
  • Initiate treatment with osteoporosis medication immediately.
  • Institute lifestyle / dietary advice.
  • Repeat DEXA in ≥ 2 years.

≤ -2.5

Absent

One or more
  • Treatment recommended though can be tailored to patient depending on absolute fracture risk.
  • Institute dietary / lifestyle advice.
  • Repeat DEXA in ≥ 2 years.

-1.0 to -2.5

Present

One or more
  • In most causes treatment should be instituted.
  • Where the patient is younger (<55) or mildly osteopaenic (-1.0 to -1.5) treatment may be reconsidered.
  • Institute dietary / lifestyle advice.
  • Repeat DEXA in ≥ 2 years.

-1.0 to -2.5

Absent

One or more
  • Treatment not necessary in most cases.
  • Consider treatment for post-menopausal women and men over 65 if T score is in lower part of the osteopaenic range (-2.0 to -2.5).
  • Institute dietary / lifestyle advice.
  • Repeat DEXA in 2-5 years, depending on severity of bone loss.

≥-1.0

Absent

Present
  • Advise on dietary / lifestyle advice and follow-up.

≤-1.5

Absent

Commencing glucocorticoids 7.5mg/day prednisolone or equivalent for at least 3 months.

  • Preventative treatment with osteoporosis medication for the duration of glucocorticoid therapy.

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Biochemical Investigations

  • Patients with a Z score less than 1.5 with risk factors should be evaluated for secondary causes of osteoporosis. The following biochemical investigations can be obtained depending on the clinical context 4,20
    • Full blood count
    • Erythrocyte sedimentation rate
    • Calcium
    • Creatinine
    • Total alkaline phosphatase and albumin
    • Thyroid stimulating hormone
    • Protein electrophoresis
    • Anti-tissue transglutaminase antibody or anti-endomysial antibody
    • Parathyroid hormone
    • 25-hydroxy vitamin D
  • Secondary causes of osteoporosis can include 20
    • Hyperthyroidism
    • Hyperparathyroidism
    • Renal failure
    • Hyper / hypocalcicuria
    • Coeliac disease
    • Hyperthyroidism
    • Haematologic disorders
    • Exogenous medications (e.g. phenytoin, glucocorticoids, tacrolimus, cyclosporine, methotrexate, lithium, proton pump inhibitors)
    • Androgen deprivation therapy

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References

Date of literature search: November 2014

The search methodology is available on request. Email

References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine, Levels of Evidence. Download the document

  1. Osteoporosis Australia. Bone density testing in general practice. [www.osteoporosis.org.au]. [cited 2014 December 2]. View the reference
  2. Hazes JM, Woolf AD. The bone and joint decade 2000-2010. J Rheumatol. 2000;27(1):1-3. (Editorial). View the reference
  3. Marshall D, Johnell O, Wedel H. Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures. BMJ. 1996;312(7041):1254-9. (Level II evidence). View the reference
  4. O'Neill S, MacLennan A, Bass S, et al. Guidelines for the management of postmenopausal osteoporosis for GPs. Aust Fam Physician. 2004;33(11):910-9. (Review article). View the reference
  5. Writing guidelines for the ISCD position development conference. Indications and reporting for dual-energy X-ray absorptiometry. J Clin Densitom. 2004;7(1):37-44. (Guideline). View the reference
  6. Kanis JA. Assessment of fracture risk and its application to screening for postmenopausal osteoporosis: a synopsis of a WHO report. WHO Study Group. Osteoporos Int. 1994;4:368-81. (Review article). View the reference
  7. Assessment of fracture risk and its application to screening for post menopausal osteoporosis: a report of WHO Study Group. World Health Organ Tech Rep Ser. 1994;843:1-129. (WHO technical series 843). View the reference
  8. Australian Government: Department of Health and Ageing. Medicare Benefits Schedule Online. [www.mbsonline.gov.au]. [updated 2013 November 5; cited 2014 December 2]. View the reference
  9. Genant HK. Current State of bone densitometry for osteoporosis. Radiographics. 1998;18(4):913-8. (Review article). View the reference
  10. Osteoporosis Australia. Prevent the next fracture - a guide for GPs. 2nd Edn. 2008.
  11. Center J, Bliuc D, Nguyen T, et al. Risk of subsequent fracture after low-trauma fracture in men and women. JAMA. 2007;297(4):387-94. (Level II evidence). View the reference
  12. Huopio J, Kroger H, Honkanen, et al. Calcaneal ultrasound predicts early postmenopausal fractures as well as axial BMD. A prospective study of 422 women. Osteoporos Int. 2004;15(3):190-5. (Level II evidence). View the reference
  13. Khaw K, Reeve J, Luben R, et al. Prediction of total and hip fracture risk in men and women by quantitative ultrasound of the calcaneus: EPIC-Norfolk prospective population study. Lancet. 2004;363(9404):197-202. (Level II evidence). View the reference
  14. Nayak S, Olkin I, Liu H, et al. Meta-analysis: accuracy of quantitative ultrasound for identifying patients with osteoporosis. Ann Intern Med. 2006;144(11):832-41. (Level II evidence). View the reference
  15. Marlin F, Lopez-Bastida J, Diez-Perez A, et al. Bone mineral density referral for dual-energy X-ray absorptiometry using quantitative ultrasound as a prescreening tool in postmenopausal women from the general population: a cost-effective analysis. Calcif Tissue Int. 2004;74(3):277-83. (Level II evidence). View the reference
  16. McCauley E, Mackie A, Elliot D, et al. Heel bone densitometry: device specific thresholds for the assessment of osteoporosis. Br J Radiol. 2006;79(942):464-7. (Level II evidence). View the reference
  17. Boehm H, Link T. Bone imaging: traditional techniques and their interpretation. Curr Osteoporos Rep. 2004;2(2):41-6. (Review article). View the reference
  18. Bliuc D, Alarkawi D, Nguyen TV, Eisman JA, Center JR. Risk of subsequent fractures and mortality in elderly women and men with fragility fractures with and without osteoporotic bone density: the Dubbo osteoporosis epidemiology study. J Bone Miner Res. 2014. (in publication) (Level I evidence). View the reference
  19. Selecki Y, Eisman JA. Osteoporosis and fragility fractures: a practical approach. MedicineToday. 2014;15(11):18-27. (Review article). View the reference
  20. Nanes MS, Kallen CB. Osteoporosis.. Semin Nucl Med. 2014;44(6):439-50. (Review article). View the reference
  21. Blake GM, Fogelman I. The role of DXA bone density scans in the diagnosis and treatment of osteoporosis. Postgrad Med J. 2007;83(982):509-17. (Review article). View the reference

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Information for Consumers


Information from this website


Information from the Royal Australian and New Zealand College of Radiologists’ website



Consent to Procedure or Treatment


Radiation Risks of X-rays and Scans


Computed Tomography (CT)


Ultrasound


Plain Radiography (X-ray)



Bone Mineral Density Scan


Computed Tomography (CT)


Plain Radiography/X-rays


Radiation Risk of Medical Imaging During Pregnancy


Radiation Risk of Medical Imaging for Adults and Children


Ultrasound


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