An initial evaluation of analyser-based phase-contrast X-ray imaging of carotid plaque microstructure

• Published in: British journal of radiology 2013-01, Vol.86 (1021), p.20120318-20120318
• Main Authors: Appel, A A, Chou, C-Y, Larson, J C, Zhong, Z, Schoen, F J, Johnston, C M, Brey, E M, Anastasio, M A
• Format: Article
• Language: English
• Subjects: Angiography - instrumentation; Atherosclerosis - diagnostic imaging; Carotid Artery Diseases - diagnostic imaging; Equipment Design; Equipment Failure Analysis; Humans; Pilot Projects; Reproducibility of Results; Sensitivity and Specificity; Short Communication; Tomography, X-Ray Computed - instrumentation
• ISSN: 0007-1285; 1748-880X
• DOI: 10.1259/bjr.20120318

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.