DEXA and Bone Mineral Density Flashcards
Define Bone Mineral Density
- The mass of bone (Kg per volume)
- It is predominantly the amount of Calcium and other minerals present in the bone
Define osteoporosis
- A progressive bone disease that is characterised by a decrease in bone mass and density which can increase fractures
- The bones microarchitecture deteriorates
What is osteoporosis scoring
- Bone mineral density is scored in a specific way and therefore can be varying degrees
How is osteoporosis scoring classified
- Classified by Name and “T-Score”
What is meant by the term “T-Score”
- This is your bone mineral density value measured against a healthy young person of the same biological sex as you
State the T- Score for Osteopenia
Osteopenia = -1.0 to -2.5
State the T-score for Osteoporosis
Osteoporosis = -2.5 or lower
Who is more likely to have osteoporosis women or men?
- Women are more prone to osteoporosis due to the changes in their hormone levels through menopause whereas men have a higher peak bone mass and therefore are less prones
State risk factors that can increase your chances of developing osteoporosis
- Prolonged Steroid Usage
- Smoking
- High intake of Alcohol
- Physical Inactivity
- Age
- Genetic History
How will osteoporosis start to present itself
- Most common presentation is through diagnosis after an unexpected fracture
State the most common osteoporotic fractures
- Wrist
- Spine
- Should
- Hip
How many people in the UK have Osteoporosis
- 3.5 million
Where are patients referred to after diagnosis of osteoporosis
- Fracture Liaison Service
What does DEXA stand for?
- Dual Energy X-ray Absorption
Describe DEXA
- Gold standard for diagnosing osteoporosis
- Uses a very low dose of ionising radiation
- Uses 2 beams of radiation: 1 for Bone; 1 for Soft Tissue
- DEXA is basically just measuring how much radiation can penetrate through the bone
How is a patient prepared before their scan?
- Patient has usually brought a pre-filled questionnaire with data the clinicians will need
- Patient’s height and weight to is added to this paperwork to calculate their Body Mass Index
- Must change patient into a gown ensuring they remove anything metal that will show on image
Describe the patient positioning for DEXA scan
- Patient will lie on tabletop supine
- 4 scans are performed: AP Left Hip; AP Lumbar Spine (L1-L4); AP Whole Spine; LAT Whole Spine
What contradictions may arise if performing a Hip View
- Patient could have had a hip replacement
What contradictions may arise if performing a Lumbar View
- Patient may have screws in their back
Describe how the AP Left Hip is positioned
- Leg are positioned the same as an AP pelvis with the toes pointing into one another to show the neck of femur
- The laser is then centres at the same point as an AP Hip
Describe how the AP Lumbar Spine is positioned
- Patient is lying supine with legs positioned with the knees bent up towards the chest and resting on a foam box for support
- Patient should have arms by their side
- Centre the laser to the midline of the patient at roughly the level of the ASIS
Describe how the AP Whole Spine is positioned
- Patient is lying supine and the legs are positioned with the knees bent up towars the chest and resting on a foam box
- Arms shoulid be by their side
- Chin should not obscure the Thoracic spine
Centre the laser to the midline of the patient at roughly the ASIS
Describe how the LAT Whole Spine is positioned
- Patient is lying supine
- Legs are positioned with knees bent up towards the chest and resting on a foam box
- Centre the laser over the midline of the coronal aspect of the spine
- The c-arm will then rotate around to take a lateral image
What are problems you may encounter when doing DEXA scan
- Patient may not be very mobile
- May not be able to transfer to the machine
- The mattress does not move therefore positioning is crucial
- They may not be able to lie flat for whole duration of scan
- Patient may not understand the procedure
- They may have not filled out the paperwork out correctly
What is the main treatment option for osteoporosis
- Maintain 100mg/ day Calcium intake
What will patients need to ensure they do for treatment when they are diagnosed with osteoporosis
- Ensure they have a balanced and specific diet to include high calcium items
- Take Calcium and Vitamin D Supplements
- Take Bisphosphonates to slow rate of bone breakdown
- Maintain reasonable level of exercise and weightbearing
