What You Can Expect: Bone Density Scan
If your doctor or specialist request a bone density scan, this is what you need to know.
A bone mineral density scan presents a way for your physician to measure the amount of mineral content of your bones usually in preparation for an operation such as artificial disc replacement (ADR). You want your bones to be as dense as possible. According to Texas Back Institute, "The more dense the bone, the stronger and the less likely it is to break."
This test would ideally be performed on bones that are most likely to break because of an osteoporosis diagnosis, including:
- Lower spine bones (lumbar vertebrae)
- The narrow neck of your thighbone (femur) next to your hip joint
- Bones in your forearm
Doctors and specialists use bone density testing to:
- Identify decreases in bone density before you break a bone
- Determine your risk of broken bones (fractures)
- Confirm a diagnosis of osteoporosis
- Monitor osteoporosis treatment
There are numerous methods to gauge a patient's bone density. The top two regions tested are the spine and hip. Most exams use low-dose radiation to ascertain the bone's mass using X-rays. In addition, bone density assessments can be completed to diagnosis osteoporosis.
Furthermore, if you are preparing for any form of spinal surgery, you will most likely need this test before inserting any metal implants such as fusion cages or artificial discs. Please note that a bone density assessment test is different from a bone scan.
Deficiencies of this medical exam include:
- Variations in testing methods. Devices that measure the density of the spinal and hip bones are more accurate but are more expensive than devices that measure the density of the peripheral bones of the forearm, finger or heel.
- Limited insurance coverage. Not all health insurance plans pay for bone density tests, so please consult with your insurance provider beforehand to see if you're covered.
- Lack of information about the cause. A bone density test can prove that you have low bone density, but it can't tell you why. To answer this, you would need a more comprehensive medical evaluation.
There are certain things you should be aware of when preparing for this exam. You should wear loose, comfortable clothing. You will be requested to remove any belts or other items from your pockets, but there's no gown changing required.
You may eat foods as normal and take your medications as prescribed by your doctor the morning of this test. Your only limitations include avoiding any vitamin pills or mineral supplements specifically calcium supplements including Tums and Rolaids the morning of your exam. Those items may interfere with your bone density test.
Be sure to tell your doctor beforehand if you've recently had a barium exam or had contrast material injected for a CT scan or nuclear medicine test. Contrast materials might interfere with your bone density test.
Luckily these exams are not only easy, they are pretty quick without any pain. Ironically, some simpler versions can be done at a local pharmacy or drugstore.
If you will be having this done at a medical facility or hospital, you will lie on your back. There are some testing devices that require you to lie on your side. A small machine will pass over your low back. You may be repositioned for the scan of your hips. The test takes less than 30 minutes.
There are no ill effects, so you can drive yourself home or to work after your bone density scan. Immediately following the scan, a doctor will read the information from the scan to you. Depending on your situation, you may need to have a follow-up appointment with the doctor to discuss the results of the scan and treatment options —if the bone density is low.
Your bone density test results are reported in two numbers: T-score and Z-score. Courtesy of the Mayo Clinic, we have a break down of what those scores mean.
Here is how a bone density scan is counted:
- If you scored a -1 and above, your bone density is considered normal.
- If you scored between -1 and -2.5, your score is a sign of osteopenia, a condition in which bone density is below normal and may lead to osteoporosis.
- If you scored a -2.5 and below, your bone density indicates you likely have osteoporosis.
Your T-score is your bone density compared with what is normally expected in a healthy young adult of your sex. Your T-score is the number of units — called standard deviations — that your bone density is above or below the average.
Your Z-score is the number of standard deviations above or below what's normally expected for someone of your age, sex, weight, and ethnic or racial origin. If your Z-score is significantly higher or lower than the average, it may suggest that something other than aging is causing abnormal bone loss. If your doctor can identify the underlying problem, that condition can often be treated and the bone loss slowed or stopped.