Carotid and cerebrovascular dual-energy computed tomography angiography: Optimization of window settings for virtual monoenergetic imaging reconstruction. Issue 130 (September 2020)

• Record Type: Journal Article
• Authors: D'Angelo, Tommaso; Lenga, Lukas; Arendt, Christophe T.; Bucher, Andreas M.; Peterke, Julia L.; Caruso, Damiano; Mazziotti, Silvio; Ascenti, Giorgio; Blandino, Alfredo; Othman, Ahmed E.; Martin, Simon S.; Albrecht, Moritz H.; Bodelle, Boris; Vogl, Thomas J.; Wichmann, Julian L.
• Is Part Of: European journal of radiology. Issue 130(2020)
• Publication Date: 2020-09
• Subjects: Carotid disease -- Dual-energy -- Computed tomography -- Computed tomography angiography -- Image postprocessing; Medical radiology -- Periodicals; Radiology -- Periodicals; Radiologie médicale -- Périodiques; Medical radiology; Periodicals; 616.075705
• DOI: 10.1016/j.ejrad.2020.109166
• Languages: English
• ISSNs: 0720-048X

Abstract

Highlights: Virtual monoenergetic images (VMI) can be calculated from dual-energy CT angiography (DE-CTA). VMI reconstructions can drastically improve vessel contrast, but require dedicated windowing. Both subjectively best (B–W/L) and objectively best (O–W/L) window settings were assessed. Ideal window settings for VMI and novel VMI + were significantly higher than for standard DE-CTA. Readers subjectively prefered M40+ reconstructions regarding overall image quality. Abstract: Purpose: Dedicated post-processing of dual-energy computed tomography angiography (DE-CTA) datasets has been shown to allow for increased vascular contrast. The goal of our study was to define optimal window settings for displaying virtual monoenergetic images (VMI) reconstructed from dual-energy carotid and cerebrovascular DE-CTA. Methods: Fifty-seven patients who underwent clinically-indicated carotid and cerebrovascular third-generation dual-source DE-CTA were retrospectively evaluated. Standard linearly-blended (M_0.6), 70-keV traditional VMI (M70), and 40-keV noise-optimized VMI (M40+) reconstructions were analyzed. For M70 and M40+ datasets, the subjectively best window setting (width and level, B–W/L) was independently determined by two observers and subsequently related with aortic arch attenuation to calculate optimized values (O–W/L) using linear regression. Subjective evaluation of image quality (IQ) between W/L settings were assessed by two additional readers. Repeated measures analysis of variance were performed to compare W/L settings and IQ indices between M_0.6, M70, and M40 + . Results: B–W/L and O–W/L for M70 were 580/210 and 560/200, and for M40+ were 1630/570 and 1560/550, respectively, higher than standard DE-CTA W/L settings (450/100). Highest subjective scores were observed for M40+ regarding overall IQ (all p < 0.001). Conclusion: Application of O–W/L settings is mandatory to optimize subjective IQ of VMI reconstructions of DE-CTA.