Feasibility of Ultra-High Resolution Supra-Aortic CT Angiography: An Assessment of Diagnostic Image Quality and Radiation Dose.

Felix Anton Ucar,Mario Alberto Abello Mercado,Marius Frenzel,Sebastian Reder,Sebastian Altmann,Ahmed E Othman,Marc A Brockmann,Carolin Brockmann

doi:10.3390/tomography7040059

Felix Anton Ucar, Mario Alberto Abello Mercado + Show 6 more

Open Access

https://doi.org/10.3390/tomography7040059

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Abstract

(1) Background: To evaluate diagnostic image quality and radiation exposure of ultra-high resolution cerebral Computed-Tomography (CT) angiography (CTA) obtained on an ultra-high resolution computed tomography scanner (UHR-CT). (2) Methods: Fifty consecutive patients with UHR-CTA were enrolled. Image reconstruction was processed with a 1024 × 1024 matrix and a slice thickness of 0.25 mm. Quantitative analyses comprising CT values, contrast–noise ratio (CNR) and signal-to-noise ratio (SNR) were performed. Subjective assessment of image quality, vessel contrast, noise, artefacts and delineation of different sized vessels were assessed by two readers on a 4-point scale. Radiation exposure was determined. (3) Results: Hounsfield values (ACI: 461.8 ± 16.8 HU; MCA: 406.1 ± 24.2 HU; BA: 412.2 ± 22.3 HU), SNR (ACI: 35.4 ± 13.1; MCA: 20.8 ± 12.4; BA: 23.7 ± 12.9) and CNR (ACI: 48.7 ± 21; MCA: 63.9 ± 26.9; BA: 48.1 ± 21.4) were remarkably high in all segments. Subjective analysis by two raters (fair agreement, k = 0.26) indicated excellent image qualities (image quality = 4; contrast = 4; noise = 3; artefacts = 4).Our analysis revealed a notably high traceability of the cerebral perforators (3 Points). Radiation exposure was at moderate dose levels (effective dose = 2.5 ± 0.6mSv). (4) Conclusions: UHR-CTA generates highly valuable image qualities that allow the depiction of vessels including cerebral perforators at acceptable dose levels. The UHR-CTA may therefore enhance the detection of small cerebral pathologies and may improve interpretability, especially in settings where high image qualities are crucial for the diagnostic accuracy.

Highlights

Computed tomography (CT) is an essential tool in neuroradiological imaging that has distinguished itself as quickly accessible and with an increasing level of diagnostic significance in clinical routine
The UHR-CTA may enhance the detection of small cerebral pathologies and may improve interpretability, especially in settings where high image qualities are crucial for the diagnostic accuracy
Hounsfield units (HU), signal-to-noise ratio (SNR) and contrast–noise ratio (CNR) were calculated for three types of arteries (ICA, middle cerebral artery (MCA) and basilar artery (BA)) in each patient, and value distribution was analyzed using a boxplot graph (Figure 1)

Summary

Introduction

Computed tomography (CT) is an essential tool in neuroradiological imaging that has distinguished itself as quickly accessible and with an increasing level of diagnostic significance in clinical routine. Clinically significant neurovascular pathologies such as aneurysms, arterial occlusions, vasculitic lesions [2], cerebrovascular malformations [3], vasospasms [4] and dissection can be small and difficult to detect, and, may be missed on standard CTAs [5]. The evaluation of these lesions can be aggravated by Hounsfield artefacts of the posterior fossa due to the high density of the skull base and the petrous bone [6]. Depending on the type of the lesion and the size of the affected vessels, the evaluability of vascular alterations would be remarkably improved by an increasing resolution and image quality

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