Properties of the prototype 256-row (cone beam) CT scanner

Area of Science:

• Medical Imaging
• Radiology
• Computed Tomography

Background:

• Cone-beam CT (CBCT) is susceptible to specific artifacts, notably Feldkamp artifacts.
• Advancements in CT technology, such as the 256-multidetector-row CT (256MDCT), necessitate evaluation of these artifacts.

Purpose of the Study:

• To evaluate Feldkamp artifacts in 256MDCT using phantom and clinical data.
• To compare the reconstruction accuracy of axial versus helical scans with 256MDCT.
• To assess image noise, slice sensitivity profile (SSP), and artifact impact on image interpretation.

Main Methods:

• Phantom studies and clinical scans (chest, abdomen) using 256MDCT.
• Comparison of 256MDCT results with a 64-multidetector-row CT (64MDCT).
• Evaluation of image noise, SSP, and artifact characteristics in axial and helical modes.

Main Results:

• Feldkamp artifacts appeared as horizontal streak artifacts at scan edges in axial mode, observed in both phantom and clinical soft-tissue regions.
• Helical scanning significantly minimized Feldkamp artifacts compared to axial scanning.
• Image noise was lower in axial scans, while SSP was superior in helical scans; artifacts generally did not impede image interpretation.

Conclusions:

• Feldkamp artifacts in 256MDCT axial scans require careful identification and can be mitigated by using helical scanning.
• 256MDCT demonstrates potential for more accurate diagnoses and enables novel CT applications due to its volumetric imaging capabilities.