Quantification of artifact reduction with real-time cine four-dimensional computed tomography acquisition methods

Area of Science:

• Medical Imaging
• Radiology
• Image Processing

Background:

• Four-dimensional computed tomography (4D CT) is crucial for visualizing moving organs in medical imaging.
• Artifacts in 4D CT can compromise diagnostic accuracy.
• Current retrospective phase sorting methods have limitations in artifact reduction and dose efficiency.

Purpose of the Study:

• To evaluate and compare artifact magnitude and frequency in simulated 4D CT images.
• To assess three real-time acquisition methods against retrospective phase sorting.
• To quantify differences in CT dose and acquisition time for each method.

Main Methods:

• Simulated 4D CT image acquisition using direction-dependent displacement, simultaneous displacement and phase, and simultaneous displacement and velocity methods.
• Utilized varying displacement and velocity tolerances with spherical phantoms and patient-specific respiratory motion data.
• Analyzed artifact magnitude, frequency, CT dose, and acquisition duration for each technique.

Main Results:

• Real-time methods demonstrated a 50% reduction in mean artifact magnitude compared to retrospective sorting.
• CT dose was approximately 50% lower with real-time methods.
• Acquisition times increased by 20% to 100% for real-time methods.

Conclusions:

• Real-time 4D CT acquisition effectively reduces artifacts and imaging dose.
• Increased acquisition time is a trade-off for real-time methods.
• Direction-dependent displacement acquisition emerges as the optimal real-time method due to its favorable balance of dose, time, and artifact reduction.