How to Prepare for a DEXA Scan
When it comes to obtaining accurate body composition measurements, the Dual-Energy X-ray Absorptiometry (DEXA) scan stands out for its precision and reliability.
For the highest degree of accuracy, patients must prepare appropriately before the scan.
Doing so will also allow for more precise follow-up exams as this can help account for any potential variables.
Below is a checklist to follow prior to coming in.
Be in a Fasted State
Eating or drinking before the scan can alter your hydration status, potentially skewing the results by slightly increasing lean mass.
Fasting ensures that your hydration levels are more consistent, providing a more accurate assessment of your body composition.
Leave >12 Hours Between Strenuous Exercise and Scanning
Exercise soon before can deplete your glycogen stores. This means that there may be less energy reserves in your muscles, leading to lower lean mass.
This is important for reproducibility. For example, if you were to train the night before one scan, and then not do that for the next, it will likely show a higher amount of lean mass in the follow-up scan despite there being no actual change.
No Alcohol Consumption <12 Hours Before Testing
Alcohol has diuretic properties, which means it increases urine production and can lead to dehydration. Dehydration, in turn, can affect body water content, potentially skewing the DEXA scan result.
Alcohol can influence the distribution of fluids within the body too and may cause temporary variations in soft tissue measurements.
Go to the Bathroom and Empty Your Bladder Before the Scan
This will help account for any additional mass that may come from food volume and water.
Do Not Wear Any Clothing With Belts, Zippers, Buttons, Metal Clasps or Underwires
Metal can absorb and scatter the X-ray beams used in the scan. This interference can create artifacts or distortions in the resulting images, leading to inaccurate measurements of bone density and body composition of that area.
Wear Lightweight, Comfortable Clothing
Tight or compact clothing, especially if it has thick seams or is made from dense materials, can slightly alter body contours or compress soft tissue. This can affect the accuracy of measurements, particularly for body composition analysis.
Loose clothing ensures that the scan is as close to the natural state of the body as possible. This uniformity is important for the reproducibility of the scans.
Summary
Properly preparing for a DEXA scan is crucial to ensure the accuracy and reliability of the results. By following the recommended protocols—such as fasting, avoiding alcohol, limiting strenuous training soon before, removing metal objects, and wearing appropriate clothing—you can significantly enhance the precision of the body composition and bone density measurements obtained from the scan.