K-edge subtraction imaging for coronary angiography with a compact synchrotron X-ray source

Abstract

About one third of all deaths worldwide can be traced back to cardiovascular diseases. An interventional radiology procedure for their diagnosis is Digital Subtraction Angiography (DSA). An alternative to DSA is K-Edge subtraction (KES) imaging, which has been shown to be advantageous for moving organs and eliminating image artifacts caused by patient movement. As highly brilliant, monochromatic X-rays are required for this method, it has been limited to synchrotron facilities so far, restraining the feasibility in clinical routine. Compact synchrotron X-ray sources based on inverse Compton scattering, which have been evolving substantially over the past decade, provide X-rays with sufficient brilliance that meet spatial and financial requirements affordable in laboratory settings or for university hospitals. In this work, we demonstrate a first proof-of-principle K-edge subtraction imaging experiment using the Munich Compact Light Source (MuCLS), the first user-dedicated installation of a compact synchrotron X-ray source worldwide. It is shown experimentally that the technique of KES increases the visibility of small blood vessels overlaid by bone structures.

A compact light source providing high-flux, quasi-monochromatic, tunable X-rays in the laboratory

“…Given the biomedical imaging research focus of the TUM group, a large number of application examples has been generated in this area. 8,[10][11][12][13][14][15][16][17][18][21][22][23][24][25][26][28][29][30][31] While earlier experiments focused on demonstrating different X-ray imaging techniques on the CLS, such as mono-energy X-ray absorption tomography, grating-based multimodal imaging, propagation-based phase contrast and phase contrast tomography, these are now applied to specific biomedical applications and extended to advanced techniques, such as dynamic imaging, K-edge subtraction imaging and others.…”

“…19,20 The MuCLS has been operating with a high degree of uptime since then and has enabled many scientific experiments and publications. [21][22][23][24][25][26][27][28][29][30][31] Generally, most X-ray techniques such as diffraction, imaging, spectroscopy or scattering can be performed with both electron-impact and synchrotron sources. While the details depend on the technique and the specific application needs, generally the following guidelines apply: Longer measurement times Shorter measurement times Lower resolution and sensitivity Higher resolution and sensitivity Suitable where fixed energy or polychromatic beam is acceptable Required where tunability and/or monochromaticity is required Advantageous for large sample sizes (e.g., imaging of large components and low or moderate resolution)…”

The versatile X-ray beamline of the Munich Compact Light Source: design, instrumentation and applications

“…In a test experiment for angiography, we demonstrated the separation of iodine, which was injected as contrast agent into the arteries, and bone. This enabled the observation of vessels behind bones, which otherwise would have been oblique (Kulpe et al, 2018). Fig.…”

“…6, the reconstructed slices are cropped to the region containing the kidney. Image reconstruction followed the filter-based approach for KES imaging in Kulpe et al (2018), which is very well suited to the spectral bandwidth available at the MuCLS. It has been extended to CT (Kulpe et al, 2019) as well as time-sequence imaging (Kulpe et al, 2020).…”

Dual-Energy X-ray Medical Imaging with Inverse Compton Sources: A Simulation Study

“…The insertion of a filter containing the same material used as contrast agent absorbs the part of the spectrum above the K-edge and shifts the mean energy of the remaining spectrum to lower energies. A dedicated algorithm of reconstruction is then applied to retrieve the contrast image [37,38].…”