http://repub.eur.nl/res/aut/697/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/18399/ 2009-03-01T00:00:00Z Visualization and quantification of small structures with computed tomography (CT) is hampered by the limited spatial resolution of the system. Histogram-based selective deblurring (HiSD) is a deconvolution method that restores small high-density structures, i.e., calcifications, of a CT image, using the high-intensity voxel information of the deconvolved image, while preserving the original hounsfield Units (HUs) in the remaining tissues. In this study, high resolution micro-CT data are used to validate the potential of HiSD to improve calcium visualization and quantification in the carotid arteries on in vivo contrast-enhanced CTA data. The evaluation is performed qualitatively and quantitatively on 15 atherosclerotic plaques obtained from ten different patients. HiSD in combination with vessel segmentation significantly improves calcification visualization and quantification on in vivo contrast-enhanced CT images. Calcification blur is reduced, while avoiding noise amplification and edge-ringing artifacts in the surrounding tissues. Calcification quantification errors are reduced by 23.5% on average. © 2006 IEEE. http://repub.eur.nl/res/pub/10601/ 2007-10-24T00:00:00Z Computed Tomography (CT) imaging of small high-density structures such as calcifications and stents is highly relevant in diagnosis, treatment planning, and follow-up of patients with cardiovascular disease. Calcification quantification is increasingly used as a potential marker for cardiovascular disease. However, owing to image blur, accurate calcification quantification is compromised. In addition, blur of high intensity structures hampers the visualization of surrounding soft tissue structures. This for example affects the assessment of the degree of vessel stenoses at locations close to calcified atherosclerotic plaques and/or stent struts. The research described in this thesis focuses on the improved of visualization and quantification of small high density structures, in particular calcifications. http://repub.eur.nl/res/pub/15442/ 2007-01-01T00:00:00Z OBJECTIVES: Computed tomography (CT) imaging of small high-density structures, eg, calcifications, is hampered by image blur. This study aims to deconvolve calcifications in the transverse and longitudinal directions while avoiding noise amplification and edge-ringing artifacts in the surrounding low-density structures. MATERIALS AND METHODS: A method referred to as histogram-based selective deblurring (HiSD) has been developed to generate a restored image by combining the low-intensity (ie, Hounsfield Units) information of the original image with the high-intensity information of the deconvolved image. HiSD is evaluated on phantom and in vitro atherosclerotic plaque CT images by comparing the original and restored images with their corresponding reference micro-CT images both qualitatively and quantitatively. RESULTS: HiSD reduces calcification blur in the transverse and longitudinal directions without introducing noise and ringing-artifacts in the surrounding tissues. Calcification area and volume measurements are significantly improved in the restored images (reducing on average overestimation by 32% and 83%, respectively). CONCLUSIONS: HiSD significantly improves CT visualization and quantification of small high-density structures imaged in vitro.