Comparison of the neck image quality of two different CT scanners

Dionysios Drakopoulos, Mostafa El-Ashmawy, Lukas Ebner, Verena C Obmann, Alan A Peters, Dominik Sieron, Karol Szyluk, Adrian T Huber, Andreas Christe

Abstract


Purpose: To compare image quality and radiation dose of two different CT scanners in neck imaging.

Material and Method: 200 consecutive patients with neck CT were selected from 2014 to 2017: 100 patients underwent a CT exam at CT1 and 100 patients were examined with CT2. At both CTs, a tube voltage of 120 kVp, and a reconstructed slice thickness of 3 mm with a soft Kernel were applied. The signal-to–noise ratio (SNR) and the contrast-to–noise ratio (CNR) were calculated from the level of the vertebral body C5. SNR and CNR were standardized to the dose level used (√(CTDI)). Mann Whitney test was applied to compare the image technical/quality parameters and the figure of merit (FOM) of both CTs.

Results: Significantly less radiation dose was administered at CT1 (9.5±6.7 mGy) compared to CT2 (11.6±2.1 mGy; P < 0.001). In contrast, the image parameters were superior on CT2: SNR and CNR were 8.1±3.0 and 11.0±6.1 at CT1 and 11.5±7.3 and 12.2±5.0 at CT2 (P < 0.001 and 0.024 respectively). The standardized SNR, CNR, and FOM were not significantly different between the two scanners.

Conclusion: The presented results suggest that CT2 provides significantly better image quality delineated by SNR and CNR when compared to CT1. However, the dose adjusted image quality and the figure of merit of the two CTs were the same.


Keywords


Computed-Tomography; radiation dose; image quality; signal to noise; contrast to noise; figure of merit

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DOI: http://dx.doi.org/10.36162/hjr.v7i3.498

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