DEXA Body Composition Analysis & DXA Clinical Applications

Question 1

Which three compartments does a standard DXA body composition scan quantify?

Accepted Answer

Lean mass, fat mass, and bone mineral content

Answer

DXA partitions the body into lean soft tissue mass, fat mass, and bone mineral content (BMC), making it a three-compartment model.

Question 2

In DXA body composition analysis, the term 'android fat distribution' refers to excess fat primarily located in the:

Accepted Answer

Abdominal and trunk region

Answer

Android (apple-shaped) fat distribution is characterized by excess adipose tissue in the abdominal and trunk region, which is associated with higher cardiometabolic risk.

Question 3

What is the Visceral Adipose Tissue (VAT) region automatically estimated by advanced DXA software typically approximated from?

Accepted Answer

The android region scan data combined with validated algorithms

Answer

Modern DXA systems estimate VAT using the fat distribution within the android region combined with proprietary validated algorithms, without requiring MRI or CT.

Question 4

Which metric best describes the ratio of appendicular lean mass to body weight squared, commonly used to screen for sarcopenia?

Accepted Answer

Relative skeletal muscle index (RSMI)

Answer

The Relative Skeletal Muscle Index (RSMI) is calculated as appendicular lean mass (kg) divided by height squared (m²) and is a primary DXA-based criterion for diagnosing sarcopenia.

Question 5

When performing a whole-body DXA scan for body composition, the patient's arms must be:

Accepted Answer

Positioned palms down, slightly separated from the body sides

Answer

Arms are placed palms down with a slight gap from the torso so that the software can correctly separate arm from trunk regions during segmentation.

(DEXA) DEXA Bone Density Scan Certification Practice Test

(DEXA) DEXA Bone Density Scan Certification Practice Test

DEXA Body Composition Analysis & DXA Clinical Applications