DEXA Scan Operation & Technique 5

Question 1

Which patient condition requires the technologist to exclude a vertebra from lumbar spine BMD analysis?

Accepted Answer

A vertebra with BMD more than 1 SD different from adjacent vertebrae due to artifact or deformity

Answer

A vertebra that differs by more than 1 SD from adjacent vertebrae due to artifact, fracture, or degenerative disease should be excluded from the mean BMD calculation.

Question 2

During a forearm DXA scan, the non-dominant arm is typically scanned. When should the dominant arm be scanned instead?

Accepted Answer

When the non-dominant arm has a fracture, cast, or cannot be positioned correctly

Answer

The dominant forearm is substituted when the non-dominant arm is unavailable due to injury, cast, surgical hardware, or positioning limitations.

Question 3

How is the 'least significant change' (LSC) used in serial DXA monitoring?

Accepted Answer

It is the minimum BMD change that exceeds measurement precision error and can be considered real

Answer

The LSC, calculated from precision data, defines the threshold above which a BMD change is statistically significant and not attributable to measurement error.

Question 4

A patient receiving long-term glucocorticoid therapy is referred for a DXA scan. Which additional scan site should be considered beyond the standard spine and hip?

Accepted Answer

Distal forearm (radius)

Answer

ISCD guidelines recommend adding a forearm scan for patients on long-term glucocorticoids because steroid-induced bone loss may be more pronounced at cortical sites like the radius.

Question 5

What is the correct method for measuring the ulnar length during a forearm DXA scan setup?

Accepted Answer

From the olecranon to the ulnar styloid with the elbow bent at 90°

Answer

Ulnar length is measured from the olecranon process to the ulnar styloid with the elbow flexed to 90°, and is used by DXA software to calculate the 33% radius site location.

(DEXA) DEXA Bone Density Scan Certification Practice Test

(DEXA) DEXA Bone Density Scan Certification Practice Test

DEXA Scan Operation & Technique 5