DEXA
What is a DEXA Scan?
Dual Energy X-ray Absorptiometry (DEXA) is a very low dose x-ray
scan that measures bone mineral density (BMD) to determine
bone loss. This allows an
accurate assessment of an individual patient’s fracture risk or requirement
for treatment.
Why do a DEXA Scan?
DEXA scans are used to diagnose osteoporosis. This condition most
often affects post-menopausal women but can also occur in men
and younger individuals with certain medical conditions. With
osteoporosis there is a gradual loss of bone density that causes
bones to become more fragile, often resulting in fractures, even
with minimal trauma. If a DEXA scan shows that bone density is
low there are now treatment options that can help prevent fractures.
Because bone loss can be ongoing, periodic DEXA scans can be
used to track bone mineral density over time. Also, once a patient
is placed on a treatment regimen for osteoporosis, regular DEXA scans
are usually recommended to determine if the treatment is working for a
given patient.
Bone density testing is strongly recommended if the patient:
- is post-menopausal
- is a male with medical conditions associated with osteoporosis
- is using steroids over a prolonged period of time
- is using excessive thyroid hormones
- is using certain anti-convulsants
- has a family history of osteoporosis
- has excessive alcohol or caffeine consumption
- is a smoker
- has Type 1 diabetes, liver disease, or kidney disease
- has had a vertebral fracture, hip fracture, or fracture after only minor trauma
- has hyperthyroidism
How is a DEXA Scan performed?
The exam is quite simple and takes only about 15 to 20 minutes.
The patient lies on a table while the imager makes passes overhead. Bone
density is usually measured at two locations, the hip and the
lower spine. A technologist will sit next to the examination
table to monitor the procedure at a computer to assure that the imaging
is adequate for accurate measurements.
How should I prepare for a DEXA scan?
On the day of the exam, follow your normal diet. Wear loose, comfortable clothing,
avoiding garments with metal such as zippers or buttons. There is no other preparation however you may need a referral number.
Other important information:
Inform our scheduling department if you have recently had a barium x-ray exam (Upper GI or Barium enema) or have been injected with a contrast material for a CT scan since that may interfere with accurate DEXA measurements. If so your test may need to be scheduled approximately 10-14 days after those procedures.
The maximum weight that can be accommodated on our DEXA table is 280 lbs. For patients weighing more, the bone mineral density in their forearm will be measured on the DEXA table.
Women should always inform their physician or x-ray technologist if there is a possibility that they may be pregnant. Even though a low dose, DEXA does use x-rays and should be avoided if possible during pregnancy.
How will I learn about the results?
Once the density is calculated, it is reviewed by a radiologist and is compared to standards. The results are then sent promptly to your doctor who will discuss them with you, and discuss treatment options if necessary.