Translation of Atherosclerotic Plaque Phase-Contrast CT Imaging from Synchrotron Radiation to a Conventional Lab-Based X-Ray Source

Abstract

ObjectivesPhase-contrast imaging is a novel X-ray based technique that provides enhanced soft tissue contrast. The aim of this study was to evaluate the feasibility of visualizing human carotid arteries by grating-based phase-contrast tomography (PC-CT) at two different experimental set-ups: (i) applying synchrotron radiation and (ii) using a conventional X-ray tube.Materials and MethodsFive ex-vivo carotid artery specimens were examined with PC-CT either at the European Synchrotron Radiation Facility using a monochromatic X-ray beam (2 specimens; 23 keV; pixel size 5.4 µm), or at a laboratory set-up on a conventional X-ray tube (3 specimens; 35-40 kVp; 70 mA; pixel size 100 µm). Tomographic images were reconstructed and compared to histopathology. Two independent readers determined vessel dimensions and one reader determined signal-to-noise ratios (SNR) between PC-CT and absorption images.ResultsIn total, 51 sections were included in the analysis. Images from both set-ups provided sufficient contrast to differentiate individual vessel layers. All PCI-based measurements strongly predicted but significantly overestimated lumen, intima and vessel wall area for both the synchrotron and the laboratory-based measurements as compared with histology (all p<0.001 with slope >0.53 per mm2, 95%-CI: 0.35 to 0.70). Although synchrotron-based images were characterized by higher SNRs than laboratory-based images; both PC-CT set-ups had superior SNRs compared to corresponding conventional absorption-based images (p<0.001). Inter-reader reproducibility was excellent (ICCs >0.98 and >0.84 for synchrotron and for laboratory-based measurements; respectively).ConclusionExperimental PC-CT of carotid specimens is feasible with both synchrotron and conventional X-ray sources, producing high-resolution images suitable for vessel characterization and atherosclerosis research.

Ex vivo differential phase contrast and magnetic resonance imaging for characterization of human carotid atherosclerotic plaques

“…There are a few studies [25][26][27][28] reporting on the application of phase contrast imaging to atherosclerotic vessels and findings are in good agreement with our results.…”

X-Ray Phase-Contrast Tomography of Renal Ischemia-Reperfusion Damage

“…GB-PCI can be translated from synchrotron to more accessible experimental laboratory based conditions [12] . Other studies performed at lab-based GB-PCI-settings confirmed an increase in soft-tissue contrast and a gain of complementary information for example in arteries [29] and human breast tissue [26] despite the lower density- and spatial resolution compared to synchrotron experiments. We anticipate a similar benefit for imaging of renal tissue.…”

“…In synchrotron studies, it has proven excellent soft-tissue contrast and high-resolution volumetric data of various biomedical samples [23] , [24] . Several studies on biomedical samples conducted at polychromatic x-ray sources have shown improved imaging of parenchymal lung disease [25] , breast lesions [26] , [27] , cartilage [28] , and atherosclerotic plaques [29] at good density resolution and reasonable spatial resolution.…”

In-line phase-contrast and grating-based phase-contrast synchrotron imaging study of brain micrometastasis of breast cancer

“…Different X-ray phase-contrast imaging methods have different characteristics. In general, GPC can provide a quantitatively correct reconstruction of the δ value for multi-material samples, which could be used to study and give high-resolution images on complex biological samples and give high-resolution images to visualize, e.g., human carotid arteries 29 , mouse body 30 , and human breast cancer tissues 31 . This is normally difficult for single-distance IPC.…”