By: Mrs. Awatef Al Ajmi Mrs. Sarah J. Ramadhan

Coordinated By: Mrs. Fatiamh Al Farhan

Bone Mineral Density (BMD)

BONE Structure

Cellular StructureThere are several types of cells constituting the bone :-Osteoblasts are bone-forming cells.They produce alkaline phosphatase which helps in

mineralisation of bone.

-Osteocytes Their functions incude matrix maintenance and

calcium homeostasis.

-Osteoclasts are the cells responsible for bone resorption,thus they break

down bone. New bone is then formed by the osteoblasts.

Women build bone from birth until age 30-35 yr when they achieve peak bone mass.

●  Most women maintain peak bone mass until menopause.

●  Bone loss occurs most rapidly in the first 3 yrs after menopause.

●  Increased life expectancymore years of potential bone loss.

Bone Facts

Means "porous bones," causes bones to become weak and brittle – so brittle that even mild stresses like bending over, lifting a vacuum cleaner or coughing can cause a fracture.

NORMAL OSTEOPOROSIS

Osteoporosis

MANY PEOPLE WON’T KNOW

UNTIL THEY HAVE THEIR 1ST FRACTURE

THEY HAVE OSTEOPOROSIS

Risk Factors

RISK FACTORS FOR OSTEOPOROSIS

1. Steroid medications > 3 months2. Chronic anticonvulsant therapy3. Men with low testosterone, any other secondary

cause of osteoporosis4. Chronic kidney disease5. Early menopause 6. History of hormone treatment for prostate cancer

or breast cancer7. Strong family history of osteoporosis8. Significant loss of height (vertebral compression

fractures)

Generally breaks the bones of the:

• Wrist• Spine• Hip

Osteoporotic Patient

• The diagnosis of osteoporosis can be made by using conventional radiography and by measuring the BMD using DEXA which is the gold standard for diagnosis.

Diagnosis

The main radiographic features of generalized osteoporosis are cortical thinning and increased radiolucency.

Diagnosis

What is a Bone Mineral Density (BMD) test?

• A bone mineral density test is an easy,reliable test that measures the density or thickness of bones.

• It measures the amount of mineral (calcium) in a specific area of the bone.

• The more mineral in the bone measured, the greater is the bone density or bone mass.

What are guidelines for doing a BMD Examination?

A BMD test can:

1. Measures the bone mineral density and compares it to that of an established standard.

2. Detect osteoporosis before a fracture occurs

3. Monitor the effectiveness of treatments for osteoporosis and osteopenia.

How does the procedure work?• The DEXA machine sends a thin, invisible beam of

low-dose x-rays with two distinct energy peaks through the bones being examined.

• One peak is absorbed mainly by soft tissue and the other by bone.

• The soft tissue amount can be subtracted from the total and what remains is a patient’s bone mineral density.

• DEXA machines feature a special software that compute and display the bone density measurements on a computer monitor.

Procedure

1. This examination is usually done on an outpatient basis.

2. Dexa measures bone density in the hip and spine or forearm.

3. The patient lies on a padded table.

4. An x-ray generator is located below the patient and an imaging device, or detector, is positioned above.

Lumbar Spine Position

To assess the spine, the patient's legs are supported on a padded box to flatten the pelvis and lower (lumbar) spine.

• Use High definition for

patients with heavy weight.• Cover from L1-L4.• The Lines have to be parallel

to intervertebral space.• Avoid Metals• Delete osteophyte

Spine Region of Interest (ROI)

Correct Spine ROI

The spine is in the center of the image including all L1-L4 vertebrae

● (1) All of L4 (1) is shown.

● (2) The top of L5 (2) is shown.

● (3) Approximately lower half of T12 (with ribs) is shown.

Result

Hip Joint position

• To assess the hip, the patient's foot is placed in a brace that rotates the hip inward.

Hip Joint Region of Interest (ROI)

• Use femoral neck, or total proximal femur whichever is lowest.

• BMD may be measured at either hip.

• Internal rotation of femur so that no or little lesser trochanter is visualized.

Correct Hip ROI

The Femur image shows the greater trochanter (1), femoral neck (2), and ischium (3).

A minimum of three centimeters of tissue should be shown above the greater trochanter and below the ischium.

The Neck ROI should be positioned as follows:

● The Neck ROI includes no part of the greater

trochanter

● The Neck ROI includes soft tissue on either side of the neck

● The Neck ROI is perpendicular to the femoral neck

● The Neck ROI contains little or no ischium

Correct Hip ROI

• Femoral mid line.• Ward’s Triangle.• Intertrochanteric line.

Correct Hip ROI

Result

Hip and/or spine cannot be measured or interpreted.

• Hyperparathyroidism

• Very obese patients (over

the weight limit for DXA table)

Alternative Procedure(Forearm)

• Use 33% radius (one- third radius)

• use the non dominant forearm for diagnosis.

• measure the forearm to the ulna styloid (A)

Positioning the C-arm

Left Forearm Scan:start at the mid-forearm.

Right Forearm scan:start at the first row of carpal bones.

Correct Forearm ROI

(1) The Reference line is located at the distal tip of the ulna styloid process

(2) The UD ROI does not contain the radial endplate [UD = ultradistal)

(3) The vertical lines in the center of the UD and 33% ROIs are located between the radius and ulna.

• Osteoarthritis •  Previous barium, contrast/

radionuclide studies •  Stones • Bony disorders:

Bony lesions w increased density e.g. compression fracture, osteoblastic lesions increased BMD

Internal Artifacts

Barium in GI tract

Myelographic contrast medium

Spinal fixation

Internal Artifacts

Results

• The results of the test are usually reported as a "T score" and "Z score."

T-SCORE

• The T score compares your bone density with that of healthy young adult.

• A score of 0 means your BMD is equal to the standard for a healthy young adult.

Z-SCORE• The Z score compares your bone density

with that of other people of same age, gender, wt and ethnicity.

• A low Z-score (below —2.0) is a warning sign that you have less bone mass or that you are losing bone more rapidly than expected for someone of your age.

 

Results

• In either score, a negative number means you have thinner bones than the standard.

• The more negative the number, the higher your risk of a bone fracture.

No Z score

How Often ?

• 2 years for women with osteoporosis or who are at high risk.

• Because the response to treatment occurs slowly, this is usually an acceptable time interval.

• 6 months In cases with high bone turnover rates, like women taking high-dose steroids.

• Awareness is essential amongst general public.• Always ask the patient about the last BMD done, any

surgical procedure, or contrast study done recently.• Correct positioning, scanning and analysis help in patients

diagnosis and treatment.

Take Home Points

alciumC

DVitamin

xerciseE

FPrevent alls

ain weightG

Stop mokingS

Prevention is the best treatment