Do you want an overview of what a Dexa scan can offer amidst the jumble of body composition assessments? – Here’s a walkthrough of the method!

This blog post explains what Dexa can offer among the many available methods to assess body composition. We will address the questions: How does a Dexa scanner work, and how does it describe your body composition? Let’s get started.

The Dexa method

A Dexa scanner works by sending very weak X‑rays at two different energy levels through your body. Your tissues attenuate the rays differently, which allows Dexa to divide your body into three distinct compartments: bone, fat, and lean mass [1-4]. A DEXA scan typically takes about 10 minutes, making it a fast way to gain insight into your body composition. You get information on your bone health, fat tissue, and lean mass all at once.

Dexa’s three compartments offer a versatile analysis

The more compartments a body composition method can divide the body into, the fewer uncertainties and assumptions it typically relies on [5-8].

Dexa scanning offers a validated 3-compartment analysis with Bone, Fat and Lean mass, unlike bioimpedance, underwater weighing, plethysmography and anthropometric measurements (skinfold measurements and waist circumference), which all basically divide the body into only 2 compartments; Fat mass and Fat free mass [2, 3, 6-9].

An advantage of Dexa scanning is therefore that it not only divides the body into what is fat and what is not, but describes bone tissue and lean mass separately [3]. In other words, DEXA can divide the body’s fat-free mass into two components, Bone and Lean mass. This is essential and gives rise to more versatile analysis than if bones on the one hand and tissue components such as muscles and organs on the other were lumped together as simply “fat-free mass” [2, 10, 11].

Dexa provides insight into both the whole body and individual body regions

A Dexa body composition scan provides information about the body as a whole, but also in individual body regions (arms, legs, torso, android and gynoid region, etc.). This way you get data on both Fat, Bone and Lean mass on different parts of the body and not just as one overall result. As part of this segmented analysis, Dexa also provides estimates of how much fat is around the abdominal organs in a more accurate way than bioimpedance and waist circumference measurements [12-15].

Dexa scans are performed simultaneously with minimal X-ray radiation and a very short scan time, unlike CT scans (high X-ray radiation) and MRI scans (long scan time) [6, 16-18]. Dexa thus provides a unique opportunity for a body composition assessment.

Optimizing scan accuracy; Is there anything you can do yourself for Dexa scans?

There are basically 3 things you should be aware of before a scan:

1. The scanners and models of different Dexa manufacturers differ. Therefore, to obtain the most comparable results from repeated scans, it is recommended to have the scans performed on the same scanner [8, 19-21].
In addition, it is advantageous to try to create as similar circumstances as possible from scan to scan. Methods such as bioimpedance are far more vulnerable to variations in food and fluid intake than Dexa scanning [8, 10, 20-22], but you can still try to:
2. Avoid being de- or over-hydrated during your Dexa scans.
3. Try to achieve comparable conditions in terms of food intake before scanning and therefore fast for the same number of hours each time you are scanned, if possible.

Book your Dexa scan appointment here

“Direct” and “Indirect” methods

It is generally true that all methods of estimating body composition other than dissection will be “indirect methods”. This applies to Dexa scanning and all other ways of analyzing body data, be it other imaging techniques like MRI and CT or bioimpedance, plethysmography studies, underwater weighing, skinfold measurements, waist circumference or other.

Of the methods available on the market, Dexa is the only 3-compartment study for body composition and offers both whole-body and region-specific results.

The many relevant and useful data you get from your Dexa scan is presented in a report that you can use on your journey towards weight loss, muscle building, rehabilitation, or whatever else your goal may be.

Source:

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