Brain image quality according to beam collimation width and image reconstruction algorithm: A phantom study. (April 2023)

• Record Type: Journal Article
• Authors: Greffier, Joël; Viry, Anaïs; Durand, Quentin; Hajdu, Steven David; Frandon, Julien; Beregi, Jean Paul; Dabli, Djamel; Racine, Damien
• Is Part Of: Physica medica. Volume 108(2023)
• Publication Date: 2023-04
• Subjects: CT Computed tomography -- DLR Deep learning image reconstruction -- IR Iterative reconstruction -- NPS Noise power spectrum -- ROI Region of interest -- TTF Task-based transfer function; Computed tomography -- Wide collimation CT system -- Deep-learning image reconstruction algorithm -- Brain; Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2023.102558
• Languages: English
• ISSNs: 1120-1797

Abstract

Highlights: Wide axial acquisition reduces total patient dose and image noise in comparison to helical acquisition. Wide axial acquisition does not change spatial resolution or noise texture. Subjective image quality is satisfactory for clinical use whatever the dose level, algorithm or acquisition mode. Abstract: Purpose: To compare quantitatively and qualitatively brain image quality acquired in helical and axial modes on two wide collimation CT systems according to the dose level and algorithm used. Methods: Acquisitions were performed on an image quality and an anthropomorphic phantoms at three dose levels (CTDIvol : 45/35/25 mGy) on two wide collimation CT systems (GE Healthcare and Canon Medical Systems) in axial and helical modes. Raw data were reconstructed using iterative reconstruction (IR) and deep-learning image reconstruction (DLR) algorithms. The noise power spectrum (NPS) was computed on both phantoms and the task-based transfer function (TTF) on the image quality phantom. The subjective quality of images from an anthropomorphic brain phantom was evaluated by two radiologists including overall image quality. Results: For the GE system, noise magnitude and noise texture (average NPS spatial frequency) were lower with DLR than with IR. For the Canon system, noise magnitude values were lower with DLR than with IR for similar noise texture but the opposite was true for spatial resolution. For both CT systems, noise magnitude was lower with the axial mode than with the helical mode for similar noise texture and spatial resolution. Radiologists rated the overall quality of all brain images as "satisfactory for clinical use", whatever the dose level, algorithm or acquisition mode. Conclusions: Using 16-cm axial acquisition reduces image noise without changing the spatial resolution and image texture compared to helical acquisitions. Axial acquisition can be used in clinical routine for brain CT examinations with an explored length of less than 16 cm.