title: An initial evaluation of analyser-based phase-contrast X-ray imaging of carotid plaque microstructure.
abstract: Carotid artery plaque instability can result in rupture and lead to ischaemic stroke. Stability of plaques appears to be a function of composition. Current non-invasive imaging techniques are limited in their ability to classify distinct histological regions within plaques. Phase-contrast (PC) X-ray imaging methods are an emerging class of techniques that have shown promise for identifying soft-tissue features without use of exogenous contrast agents. This is the first study to apply analyser-based X-ray PC imaging in CT mode to provide three-dimensional (3D) images of excised atherosclerotic plaques. The results provide proof of principle for this technique as a promising method for analysis of carotid plaque microstructure. Multiple image radiography CT (MIR-CT), a tomographic implementation of X-ray PC imaging that employs crystal optics, was employed to image excised carotid plaques. MIR-CT imaging yields three complementary images of the plaque's 3D X-ray absorption, refraction and scatter properties. These images were compared with histological sections of the tissue. X-ray PC images were able to identify the interface between the plaque and the medial wall. In addition, lipid-rich and highly vascularized regions were visible in the images as well as features depicting inflammation. This preliminary research shows MIR-CT imaging can reveal details about plaque structure not provided by traditional absorption-based X-ray imaging and appears to identify specific histological regions within plaques. This is the first study to apply analyser-based X-ray PC imaging to human carotid artery plaques to identify distinct soft-tissue regions.
authors.affiliation: Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Appel
authors.forename: C-Y
authors.initials: CY
authors.lastname: Chou
authors.forename: J C
authors.initials: JC
authors.lastname: Larson
authors.forename: Z
authors.initials: Z
authors.lastname: Zhong
authors.forename: F J
authors.initials: FJ
authors.lastname: Schoen
authors.forename: C M
authors.initials: CM
authors.lastname: Johnston
authors.forename: E M
authors.initials: EM
authors.lastname: Brey
authors.forename: M A
authors.initials: MA
authors.lastname: Anastasio
mesh_terms: D000792:Angiography / Q000295:instrumentation*; D050197:Atherosclerosis / Q000000981:diagnostic imaging*; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*