Clinical magnification error in lateral spinal digital radiographs

Area of Science:

• Radiology
• Medical Imaging
• Spinal Diagnostics

Background:

• Magnification error in plain radiographs is typically estimated between 15% and 30%.
• The variability of magnification error in digital spinal radiographs remains unassessed.
• Accurate spinal measurements are crucial for diagnosis and treatment planning.

Purpose of the Study:

• To determine the range of clinical magnification error in lateral spinal digital radiographs.
• To evaluate the impact of body mass index (BMI) on this magnification error.
• To compare digital radiograph measurements with computed tomography (CT) and magnetic resonance imaging (MRI) for accuracy.

Main Methods:

• Observational study analyzing 250 patients with digital radiographs and CT/MRI.
• Digital imaging software used to measure anteroposterior vertebral body dimensions at C2, C5, L1, and L4.
• Magnification values calculated by comparing digital radiograph measurements to CT/MRI; patient BMI obtained via chart review.

Main Results:

• Mean magnification observed at the cervical spine (1.22) and lumbar spine (1.31), with ranges up to 1.57 and 1.63 respectively.
• Significant positive correlation found between patient BMI and magnification error at both cervical and lumbar spine levels.
• Obese patients exhibited significantly higher magnification errors compared to nonobese patients at both spinal levels.

Conclusions:

• Linear measurements from spinal digital radiographs are prone to significant magnification errors.
• This magnification error is directly correlated with a patient's body mass index (BMI).
• Clinical decisions based on uncorrected radiograph measurements are invalid; CT/MRI data can help correct for this error.