Fig 1.
ROIs position for CNR evaluation in the CTP404 module of the Catphan-504 phantom.
The depicted ROIs refer to the LDPE contrast insert.
Table 1.
CT scanners enrolled in the study.
Table 2.
Nominal HU values of the Catphan-CTP404 module inserts [58].
Table 3.
Clinical head CT imaging protocols used for each scanner by the staff of various Radiology/Neuroradiology departments at the Pisa university hospital.
Table 4.
Noise (σ) values (mean ± standard deviation across five repeated measurements), for each CT scanner/acquisition protocol.
Fig 2.
Noise power spectrum (NPS) of images acquired using different CT scanners/acquisitions protocols.
Panels A, B, C, D and E show the NPS curves (mean ± standard deviation across five repeated measurements) for Toshiba-16, GE-16RT, GE-64VCT, Siemens-64 and GE-128 scanners, respectively. In order to better compare the different NPS curves, panel F shows on the same graphic the NPS curves for all scanners/acquisition protocols.
Table 5.
Peak position of NPS curves for each CT scanner/acquisition protocol.
Table 6.
CNR values (mean ± standard deviation across five repeated measurements) of different inserts from the CTP404 phantom, for each CT scanner/acquisition protocol.
Fig 3.
Modulation transfer function (MTF) curves of images acquired using different CT scanners/acquisitions protocols.
Panels A, B, C, D and E show the MTF curves (mean ± standard deviation across five repeated measurements) for Toshiba-16, GE-16RT, GE-64VCT, Siemens-64 and GE-128 scanners, respectively. In order to better compare the different MTF curves, Panel F shows on the same graphic the MTF curves for all scanners/acquisition protocols, with a zoomed in version for the 40%-60% range of MTF.
Table 7.
Spatial frequencies (mean ± standard deviation across five repeated measurements) corresponding to 50% (f50%) and 10% (f10%) of the MTF curves, for each CT scanner/acquisition protocol.
Fig 4.
Low-contrast detectability (LCD) curves of images acquired using different CT scanners/acquisition protocols.
Panels A, B, C, D and E show the LCD curves (mean ± standard deviation across five repeated measurements) for Toshiba-16, GE-16RT, GE-64VCT, Siemens-64 and GE-128 scanners, respectively. In order to better compare the different LCD curves, Panel F shows on the same graphic the LCD curves for all scanners/acquisition protocols.
Table 8.
NUI values (mean value ± standard deviation across five repeated measurements) for each CT scanner/acquisition protocol.