Measurements of carotid intima media thickness in non-invasive high-frequency ultrasound images: the effect of dynamic range setting

Cardiovascular Ultrasound

Research

Therese Seierstad¹  Mario Gaarder² 

[1] Department of Radiology and Nuclear Medicine, Oslo University Hospital, P.O. Box 4950, 0424, Nydalen, Oslo, Norway;Department of Radiology and Nuclear Medicine, Oslo University Hospital, P.O. Box 4950, 0424, Nydalen, Oslo, Norway;Faculty of Clinical Medicine, University of Oslo, P.O. Box 1078, 0316, Blindern, Oslo, Norway;

关键词: Carotid intima media thickness;    Dynamic range;    Ultrasound;    Carotid arteries;   

DOI  :  10.1186/1476-7120-13-5

 received in 2014-11-01, accepted in 2015-01-22,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundCarotid intima media thickness (CIMT) measured with ultrasound (US) is widely used as biomarker for arteriosclerosis and as surrogate endpoint in interventional studies to assess efficacy of drug therapies. Strict US protocols are necessary to ensure reproducibility. The range of US signal intensities used for image formation, the dynamic range (DR), is rarely reported in studies and little is known about its effect on CIMT measurements in humans. The purpose of this study was to quantify the impact of DR on measurements of CIMT.MethodsUS was used to examine 313 carotid arteries in participants from two different clinical studies. For each artery, images with DR of 40, 55, 70 and 85 dB were captured from the same frozen US frame. Mean CIMT (CIMTmean), maximum CIMT (CIMTmax) and standard deviation of CIMT (CIMTsd) were obtained for all images. CIMT for different DRs were compared using student t-test.ResultsCIMTmean for 40, 55, 70 and 85 dB were 0.529, 0.564, 0.590 and 0.605 mm respectively. For CIMTmax the corresponding values were 0.626, 0.667, 0.698, and 0.716 mm. CIMTmean and CIMTmax increased significantly for increasing DR steps (p < 0.01). The relative change in CIMTmean and CIMTmax were largest between 40 and 55 dB (6.7% and 7.0%) and smallest between 70 and 85 dB (2.6% and 2.7%) indicating a declining dependency for increasing DR.ConclusionsDR significantly changes CIMT measurements and the changes are most prominent for lower DRs. The effect of changing DR is larger in human arteries than in phantoms. Reporting the DR will therefore increase the validity of CIMT data.

【 授权许可】

CC BY   
© Gaarder and Seierstad; licensee BioMed Central. 2015