When measuring the proximal femur, how should the neck region of interest (ROI) be positioned?

• A. Parallel to the table
• B. At an angle to the femoral neck
• C. Perpendicular to the femoral neck
• D. Centered on the head of the femur

Answer: (C)

In bone densitometry, the accurate assessment of bone mineral density in the proximal femur is crucial, as this area is particularly susceptible to osteoporotic fractures. When measuring the neck region of interest (ROI), it should be positioned perpendicular to the femoral neck. This alignment ensures that the densitometric measurements taken are as precise and representative as possible, minimizing the influence of any variations in bone structure or positioning that could skew the results.

Positioning the ROI perpendicular to the femoral neck allows for an optimal projection of bone density, facilitating a reliable comparison with reference values and supporting clinical decisions regarding the diagnosis and treatment of osteoporosis. This approach maximizes the visibility of the bone structure and minimizes artifacts that might arise from improper angling, ultimately leading to more accurate assessment of bone health.