Positioner and clothing artifact can affect one-third radius bone mineral density measurement

Area of Science:

• Medical Imaging
• Bone Densitometry
• Radiologic Technology

Background:

• Dual-energy X-ray absorptiometry (DXA) is a standard method for measuring bone mineral density (BMD).
• Accurate BMD measurements are crucial for diagnosing osteoporosis and monitoring treatment efficacy.
• Technical variations in DXA scanning can introduce errors, impacting diagnostic accuracy.

Purpose of the Study:

• To identify a confounder in radius DXA measurements.
• To propose a technical approach to improve the accuracy of forearm BMD assessments.
• To evaluate the impact of automated soft tissue identification errors on radius BMD.

Main Methods:

• A precision study was conducted involving 3 technologists assessing 60 individuals (30 men, 30 women).
• Forearm DXA images (n=360) were visually examined for errors in automated soft tissue point-typing.
• The effect of incorrect point-typing, specifically due to positioner slots, on one-third radius BMD was analyzed.

Main Results:

• Significant differences in radius BMD least significant change (p<0.001) were found between technologists.
• Suboptimal soft tissue point-typing occurred in 8.3% of scans (30/360), often due to forearm positioner slots or clothing.
• Incorrect point-typing involving positioner slots led to an approximate 7% higher mean one-third radius BMD.

Conclusions:

• Forearm positioner slots at scan edges can cause automated soft tissue identification errors.
• These errors result in inaccurate one-third radius BMD measurements.
• DXA technologists must exclude positioner slots from forearm scans and routinely check point-typing accuracy.