Quantitation of clinical feedback on image quality differences between two CT scanner models.

Area of Science:

• Medical Imaging
• Radiology
• CT Technology

Background:

• Radiologist feedback indicated perceived differences in image quality between GE LightSpeed VCT (VCT) and Discovery HD750 (HD) CT scanner models.
• Quantitative assessment of image quality parameters is crucial for optimizing diagnostic performance.

Purpose of the Study:

• To quantitatively compare image quality metrics, specifically noise and low contrast detectability (LCD), between GE VCT and HD CT scanner models.
• To validate radiologist observations regarding scanner performance differences.

Main Methods:

• Analysis of 3 years of Quality Control (QC) phantom images from five VCT and five HD scanners to measure noise magnitude (CT-number standard deviation) and noise power spectrum (NPS).
• Low contrast detectability (LCD) assessment using a phantom scanned on four VCT and four HD scanners.
• Image quality evaluation on an anthropomorphic phantom using eight scanners, with regions of interest in the abdomen (liver, stomach, spleen).

Main Results:

• GE HD scanners exhibited an 8.5% higher noise magnitude compared to VCT scanners.
• Noise power spectra magnitude increased with noise, but peak and mean NPS frequencies were similar between models.
• VCT scanners achieved an average of 13.1% better LCD performance than HD scanners across all phantoms and scanners.

Conclusions:

• GE VCT scanners demonstrate superior low contrast detectability compared to HD scanners.
• Higher noise levels in HD scanners correlate with observed image quality differences.
• Findings support radiologist feedback and highlight the need to review and optimize body CT protocols across different scanner models.