DEXA and Bone Mineral Density

Question 1

Define Bone Mineral Density

Answer 1

• The mass of bone (Kg per volume)
• It is predominantly the amount of Calcium and other minerals present in the bone

Question 2

Define osteoporosis

Answer 2

• A progressive bone disease that is characterised by a decrease in bone mass and density which can increase fractures
• The bones microarchitecture deteriorates

Question 3

What is osteoporosis scoring

Answer 3

• Bone mineral density is scored in a specific way and therefore can be varying degrees

Question 4

How is osteoporosis scoring classified

Answer 4

• Classified by Name and “T-Score”

Question 5

What is meant by the term “T-Score”

Answer 5

• This is your bone mineral density value measured against a healthy young person of the same biological sex as you

Question 6

State the T- Score for Osteopenia

Answer 6

Osteopenia = -1.0 to -2.5

Question 7

State the T-score for Osteoporosis

Answer 7

Osteoporosis = -2.5 or lower

Question 8

Who is more likely to have osteoporosis women or men?

Answer 8

• 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

Question 9

State risk factors that can increase your chances of developing osteoporosis

Answer 9

• Prolonged Steroid Usage
• Smoking
• High intake of Alcohol
• Physical Inactivity
• Age
• Genetic History

Question 10

How will osteoporosis start to present itself

Answer 10

• Most common presentation is through diagnosis after an unexpected fracture

Question 11

State the most common osteoporotic fractures

Answer 11

• Wrist
• Spine
• Should
• Hip

Question 12

How many people in the UK have Osteoporosis

Answer 12

• 3.5 million

Question 13

Where are patients referred to after diagnosis of osteoporosis

Answer 13

• Fracture Liaison Service

Question 14

What does DEXA stand for?

Answer 14

• Dual Energy X-ray Absorption

Question 15

Describe DEXA

Answer 15

• 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

Question 16

How is a patient prepared before their scan?

Answer 16

• 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

Question 17

Describe the patient positioning for DEXA scan

Answer 17

• Patient will lie on tabletop supine
• 4 scans are performed: AP Left Hip; AP Lumbar Spine (L1-L4); AP Whole Spine; LAT Whole Spine

Question 18

What contradictions may arise if performing a Hip View

Answer 18

• Patient could have had a hip replacement

Question 19

What contradictions may arise if performing a Lumbar View

Answer 19

• Patient may have screws in their back

Question 20

Describe how the AP Left Hip is positioned

Answer 20

• 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

Question 21

Describe how the AP Lumbar Spine is positioned

Answer 21

• 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

Question 22

Describe how the AP Whole Spine is positioned

Answer 22

• 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

Question 23

Describe how the LAT Whole Spine is positioned

Answer 23

• 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

Question 24

What are problems you may encounter when doing DEXA scan

Answer 24

• 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

Question 25

What is the main treatment option for osteoporosis

Answer 25

• Maintain 100mg/ day Calcium intake

Question 26

What will patients need to ensure they do for treatment when they are diagnosed with osteoporosis

Answer 26

• 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