A Comparison of Radiography, X-Ray Tomosynthesis, and CT for Intraorbital Metallic Foreign Body Screening

Area of Science:

• Radiology
• Medical Imaging
• Ophthalmology

Background:

• Screening for intraorbital metallic foreign bodies (IMFBs) is crucial before MRI.
• Current methods include questioning, record review, and imaging.

Purpose of the Study:

• To compare the screening performance of DR, DT, and CT in detecting IMFBs.
• To identify the limits of detection for different metal types.

Main Methods:

• A semi-anthropomorphic phantom with metal fragments (aluminum, steel, tungsten carbide) in a human skull model was used.
• Images were acquired using DR, DT, and CT.
• Radiologists scored detection confidence, and ROC analysis was performed.

Main Results:

• CT achieved a superior area under the ROC curve (0.90) compared to DT (0.79) and DR (0.78).
• CT outperformed DT and DR, particularly for detecting steel fragments.
• CT detected steel fragments as small as 0.4 mg, while DT and DR missed those ≤0.8 mg.

Conclusions:

• CT is the most effective imaging modality for detecting IMFBs in a phantom model.
• The superior performance of CT is mainly due to its enhanced detection of steel fragments.
• These findings are relevant for selecting appropriate imaging for pre-MRI orbit screening.