Comparing the Image Quality of a Mobile Flat-Panel Computed Tomography and a Multidetector Computed Tomography

Abstract

The aim of this study was to compare the image quality of a compact mobile flat-panel computed tomography (FPCT) capable of extremity imaging and a multidetector computed tomography (MDCT) in examinations with the same radiation dose. Imaging with the FPCT was performed with default settings. Monte Carlo simulations were used to calculate equivalent dose settings for the 320-row MDCT. Simulations were based on and validated by dose measurements. Homogeneity, geometric distortion, artifacts, accuracy of Hounsfield values, contrast, and spatial resolution were evaluated in different imaging phantoms. Whitney-Mann U Test and Spearman ρ were used for statistical analysis. Homogeneity reached 2.5% for the FPCT and 0.5% for the MDCT. Hounsfield values were more accurate and contrast to noise ratios were higher for the MDCT than the FPCT (P ≤ 0.001). The MDCT depicted more rod inserts than the FPCT did. No significant geometric distortion was detected in either modality. The FPCT was more prone to artifacts around Krischner wires with a diameter of 2 mm (P = 0.05-0.001), whereas the MDCT showed a higher amount of artifacts around wires with a diameter of 0.8 mm (P ≤ 0.001). Spatial resolution was 1 lp/mm (xy), 1.7 lp/mm (z) for the FPCT and 1 lp/mm (xy), less than 1 lp/mm (z) for the MDCT. We compared a mobile FPCT and a 320-row MDCT by using the same radiation dose for scans. We found the spatial resolution to be higher in the FPCT. Hounsfield units were more accurate and homogeneity and contrast resolution were better in MDCT. The MDCT was also less prone to artifacts from thick Kirschner wires but showed comparably more artifacts around thin wires.