(Monday, 7/15/2019) 4:30 PM - 5:30 PM
Room: Exhibit Hall | Forum 1
Purpose: Quantitative Imaging Biomarkers Alliance (QIBA) is committed to improve the value and practicality of quantitative imaging biomarkers by reducing variability across devices, sites, patients and time. QIBA profiles provide guidelines to track tumor volume change which is a biomarker indicating disease progression or response to treatment. It poses requirements of in-plane spatial resolution and voxel noise on CT scanners. This study is to evaluate performance of different models of CT scanners according to QIBA standards.
Methods: Five CT scanners were evaluated: two GE Discovery 710, one GE Revolution HD, one GE LightSpeed VCT, and one Siemens SOMATOM. Manufacturer QC phantoms and AAPM CT performance phantom were used to assess in-plane spatial resolution. The 50% Modulation Transfer Function (MTF) frequency is used to measure in-plane spatial resolution along the edge of an air insert and a soft-tissue equivalent insert. The ACR CT phantom was used to assess the image voxel noise. The software IMQUEST was used to calculate MTF (f50) from the images and voxel noise at various kVp (80, 100, 120 and 140), mA (150, 300 and 450) for all scanners. For GE scanners, MTF (f50) and voxel noise were evaluated at various Noise Indexes (NI 14 and 16), and various level of Adaptive Statistical Iterative Reconstructions (AsiR 0%, 20%, 40%).
Results: The voxel noise of all scanners tested were at least 20% lower than QIBA requirement of 60HU. The MTF (f50) of all scanners were between 0.34mm-1 and 0.41mm-1 for both air and soft tissue, which meets QIBA requirements of MTF (f50) between 0.3mm-1 and 0.5 mm-1. The newest scanner (GE Discovery 710) has highest in-plane spatial resolution with MTF (f50) at 0.41 mm-1.
Conclusion: All CT scanners were compliant with QIBA standards. It was observed that kVp, mA, NI and AsiR have minimum impact on MTF (f50).
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