Impact of iodine concentration and scan parameters on image quality, contrast enhancement and radiation dose in thoracic CT

European Radiology Experimental

Mette K. Henning¹  Trond M. Aaløkken²  Marian S. Solbak³  Safora Johansen⁴  Anne C. Martinsen⁵  Andrew England⁶ 

[1] Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway;Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway;Faculty of Medicine, University of Oslo, Oslo, Norway;Faculty of Health Sciences, Oslo Metropolitan University, Pilestredet 48, 0130, Oslo, Norway;Faculty of Health Sciences, Oslo Metropolitan University, Pilestredet 48, 0130, Oslo, Norway;Department of Cancer Treatment, Oslo University Hospital, Oslo, Norway;Faculty of Health Sciences, Oslo Metropolitan University, Pilestredet 48, 0130, Oslo, Norway;Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway;School of Allied Health Professions, Keele University, Staffordshire, England;

关键词: Contrast media;    Phantoms (imaging);    Radiation dosage;    Thorax;    Tomography (x-ray computed);   

DOI  :  10.1186/s41747-020-00184-z

来源: Springer

【 摘 要 】

BackgroundWe investigated the impact of varying contrast medium (CM) densities and x-ray tube potentials on contrast enhancement (CE), image quality and radiation dose in thoracic computed tomography (CT) using two different scanning techniques.MethodsSeven plastic tubes containing seven different CM densities ranging from of 0 to 600 HU were positioned inside a commercial chest phantom with padding, representing three different patient sizes. Helical scans of the phantom in single-source mode were obtained with varying tube potentials from 70 to 140 kVp. A constant volume CT dose index (CTDIvol) depending on phantom size and automatic dose modulation was tested. CE (HU) and image quality (contrast-to-noise ratio, CNR) were measured for all combinations of CM density and tube potential. A reference threshold of CE and kVp was defined as ≥ 200 HU and 120 kVp.ResultsFor the medium-sized phantom, with a specific CE of 100–600 HU, the diagnostic CE (200 HU) at 70 kVp was ~ 90% higher than at 120 kVp, for both scan techniques (p < 0.001). Changes in CM density/specific HU together with lower kVp resulted in significantly higher CE and CNR (p < 0.001). When changing only the kVp, no statistically significant differences were observed in CE or CNR (p ≥ 0.094), using both dose modulation and constant CTDIvol.ConclusionsFor thoracic CT, diagnostic CE (≥ 200 HU) and maintained CNR were achieved by using lower CM density in combination with lower tube potential (< 120 kVp), independently of phantom size.

【 授权许可】

CC BY