General

Synonym/Acronym:
BMD, DEXA, DXA, SXA, QCT, RA, ultrasound densitometry.

Dual-energy x-ray absorptiometry (DEXA, DXA): Two x-rays of different energy levels measure bone mineral density and predict risk of fracture.

Single-energy x-ray absorptiometry (SXA): A single-energy x-ray measures bone density at peripheral sites.

Quantitative computed tomography (QCT): QCT is used to examine the lumbar vertebrae. It measures trabecular and cortical bone density. Results are compared to a known standard. This test is the most expensive and involves the highest radiation dose of all techniques.

Radiographic absorptiometry (RA): A standard x-ray of the hand. Results are compared to a known standard.

Ultrasound densitometry: Studies bone mineral content in peripheral densitometry sites such as the heel or wrist. It is not as precise as x-ray techniques but is less expensive than other techniques.

Rationale
To evaluate bone density related to osteoporosis.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction. Bone mineral density (BMD) should not be performed until 7 to 10 days after other radiological studies depending on the tracer and dose used.

Normal Findings

• Normal bone mass with T-score value not less than –1 standard deviation from the peak bone mass of young adults.

Critical Findings and Potential Interventions
N/A