What is a DEXA SCAN?
DEXA is short for dual-energy x-ray absorptiometry. It is an enhanced form of x-ray technology and the GOLD STANDARD, meaning the most accurate method for registering fat and lean mass distribution throughout the entire body and as it quantifies your bone mass (to identify osteoporosis), and body fat including visceral fat (which correlates to your risk for hormonal imbalances and disease). The DEXA body scan is significantly more precise than other methods (including BMI, InBody, BodPod, and hydrostatic weighing) and is an excellent motivational tool for people tracking weight loss, nutrition, exercise and overall health as it details overall and specific regional measures of fat mass, lean mass, and bone mass. After each scan it is recommend you work with your dietitian nutritionist, so they can help you create a specific exercise and diet plan to improve your DEXA scan numbers which will result in enhanced overall health.
Why should I get a total body composition test using The DEXA SCAN?
The DEXA total body composition scan will give you the individual results you need to watch your progress and help keep you motivated. Similar to the scale, watching your weight improve can be motivating, however the scale doesn’t tell you if the weight you are losing is fat, muscle or both. With the DEXA, you will know if you are losing more fat or muscle which will help your dietitian nutritionist customize your diet and put you on the right track. People who should consider having a DEXA scan include: patients trying to lose weight and/or want to monitor body fat loss and muscle growth from exercise, want to reduce the risks of heart disease, diabetes, high blood pressure, high cholesterol, cancer and obesity. Athletes or bodybuilders who need to monitor muscle mass while trying to achieve a low ratio of fat to lean tissue mass are also good candidates.
What’s involved in a DEXA SCAN evaluation?
The test is simple, non-invasive and relaxing, and the machine is very open as you lay down in our DEXA body scan machine for 5 minutes. Our x-ray technician will help you lie on your back on the table. The scanner, which is positioned above you, will move back and forth as it measures your bone density or body composition. You will be asked to hold still and may be asked to keep from breathing for a few seconds while the x-ray picture is taken to prevent blurry imaging. These measurements are taken with only one pass of the scanner, and the results are immediate. Your dietitian nutritionist will review the results with you virtually or at one of our office locations.
Why is the DEXA SCAN the gold standard for measuring body composition?
Popular methods like hydrostatic weighing, the Bod Pod, the In – Body and calipers rely on calculated measurements of body fat that are influenced by uncontrollable environmental variables and human error. Underwater weighing, the pre-DEXA body composition gold standard, assumes that densities of fat mass and fat-free mass are constant. However, this doesn’t take into account a few important conflicting variables that strongly influence the equations used to calculate body density. Measurements by calipers (skin fold) and electrical impedance testing are the most common, however the most inaccurate.
How should I prepare for the scan?
On the day of the exam you may eat normally. You should not take calcium supplements for at least 24 hours before your exam. You should wear loose, comfortable clothing, avoid garments that have zippers, belts or buttons made of metal. Objects such as keys or wallets that would be in the area being scanned should be removed. You may be asked to remove dental appliances, eye glasses and any metal objects or clothing that might interfere with the x-ray images. It is also important to inform your X-ray technologist if you recently had a barium examination or have been injected with a contrast material for a computed tomography (CT) scan or radioisotope scan. You may have to wait 10 to 14 days before undergoing a DEXA test. Women should always inform their x-ray technologist if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy so the fetus will not be exposed to radiation.
How does the DEXA compare to BMI measurements?
BMI is a standard indicator; a height to weight ratio used to categorize weight status as underweight, normal, overweight and obese. The BMI system can be used to classify average individuals with average muscle mass, however it is not an accurate measurement because not everyone has the same exact lean muscle mass. For example, a body builder who is 250 pounds and 6 percent body fat can have the same BMI as an obese person who is 250 pounds with a 40 percent body fat. Weight means nothing unless you can accurately assess if it is fat or muscle.
How often should I have a DEXA scan?
The DEXA scan can be performed 2 to 3 times a year to determine how well your nutrition and exercise regimen is working, and to help your dietitian nutritionist make any necessary adjustments to help your reach your body composition goals.
How do I get started?
Contact us to schedule an appointment at our Nutrition Assessment Center at our Alexandria Virginia Office. We perform DEXA SCANS on Wednesdays between 10 and 3. At this time we will also take your weight, height and measurements. Metabolism Testing and Micronutrient Testing can also be assessed at this time, just let our receptionist know so she can schedule you appropriately.