Photon-Counting CT of the Brain: In Vivo Human Results and Image-Quality Assessment

• Type of Material: Article
• Authors: Amir Pourmorteza, Emory University; R Symons, National Institutes of Health Clinical Center, Bethesda; DS Reich, National Institutes of Health Clinical Center, Bethesda; M Bagheri, National Institutes of Health Clinical Center, Bethesda; TE Cork, National Institutes of Health Clinical Center, Bethesda; S Kappler, Siemens (S.K., S.U.), Erlangen; S Ulzheimer, Siemens (S.K., S.U.), Erlangen; DA Bluemke, National Institutes of Health Clinical Center, Bethesda
• Language: English
• Date: 2017-12-01
• Publisher: AMER SOC NEURORADIOLOGY
• Publication Version: Final Published Version
• Copyright Statement: © 2017 by American Journal of Neuroradiology
• Final Published Version (URL): http://dx.doi.org/10.3174/ajnr.A5402
• Title of Journal or Parent Work: AMERICAN JOURNAL OF NEURORADIOLOGY
• Volume: 38
• Issue: 12
• Start Page: 2257
• End Page: 2263
• Grant/Funding Information: This study was supported by the National Institutes of Health intramural research program (ZIACL090019; ZIAEB000072; ZIANS003119) and a collaborative research agreement with Siemens (Erlangen, Germany).
• Keywords: COMPUTED-TOMOGRAPHY; SIGNS; Clinical Neurology; Neurosciences & Neurology; HEAD CT; Neuroimaging; Science & Technology; EXPERIENCE; HEMORRHAGE; Life Sciences & Biomedicine; STROKE; RELIABILITY; Radiology, Nuclear Medicine & Medical Imaging
• Research Categories: Health Sciences, Radiology; Health Sciences, Pathology

Abstract

BACKGROUND AND PURPOSE: Photon-counting detectors offer the potential for improved image quality for brain CT but have not yet been evaluated in Vivo. The purpose of this study was to compare photon-counting detector CT with conventional energy-integrating detector CT for human brains. MATERIALS AND METHODS: Radiation dose-matched energy-integrating detector and photon-counting detector head CT scans were acquired with standardized protocols (tube voltage/current, 120 kV(peak)/370 mAs) in both an anthropomorphic head phantom and 21 human asymptomatic volunteers (mean age, 58.9 -8.5 years). Photon-counting detector thresholds were 22 and 52 keV (low-energy bin, 22-52 keV; high-energy bin, 52-120 keV). Image noise, gray matter, and white matter signal-To-noise ratios and GM-WM contrast and contrast-To-noise ratios were measured. Image quality was scored by 2 neuroradiologists blinded to the CT detector type. Reproducibility was assessed with the intraclass correlation coefficient. Energy-integrating detector and photon-counting detector CT images were compared using a paired t test and the Wilcoxon signed rank test. RESULTS: Photon-counting detector CT images received higher reader scores forGM-WMdifferentiation with lower image noise (all P- .001). Intrareader and interreader reproducibility was excellent (intraclass correlation coefficient, -0.86 and 0.79, respectively). Quantitative analysis showed 12.8%-20.6% less image noise for photon-counting detector CT. The SNR of photon-counting detector CT was 19.0%-20.0% higher than of energy-integrating detector CT forGMand WM. The contrast-To-noise ratio of photon-counting detector CT was 15.7% higher for GM-WM contrast and 33.3% higher for GM-WM contrast-To-noise ratio. CONCLUSIONS: Photon-counting detector brain CT scans demonstrated greater gray-white matter contrast compared with conventional CT. This was due to both higher soft-Tissue contrast and lower image noise for photon-counting CT.