Masami Ando, Abstract Co-Author: Nothing to Disclose

Naoki Sunaguchi PhD, Abstract Co-Author: Nothing to Disclose

Synho Do PHD, Abstract Co-Author: Nothing to Disclose

Yanlin Wu MS, Abstract Co-Author: Nothing to Disclose

Susanne Lee PhD, Abstract Co-Author: Nothing to Disclose

Rajiv Gupta PhD, MD, Presenter: Speaker, Siemens AG

Andrea Schmitz, Abstract Co-Author: Nothing to Disclose

Tetsuya Yuasa PhD, Abstract Co-Author: Nothing to Disclose

X-ray Dark Field imaging considerably increases the soft tissue contrast using ultra-small angle refractions and phase alterations arising from intrinsic electron density differences between various tissue types.  

Traditional X-ray imaging visualizes attenuation differences between various tissue types. Phase contrast imaging (PCI) has been shown to markedly increase image contrast by accentuating tissue differences based on phase alterations as the X-ray wave travels through tissue. This paper describes a new PCI technique called X-ray Dark Field Imaging (XDFI) and evaluates its capabilities using ex-vivo tissue specimens.

Components of atherosclerotic plaque including the atheroma, fibrous components, calcifications, and fibrous cap could be clearly visualized and quantified in all arterial specimens. In the eye specimen, the anatomy of the anterior chamber could be detailed with much higher resolution and fidelity than conventionally seen on CT and MRI images. For example, the cornea, iris, ciliary body and muscle, the lens along with its suspensory mechanism, and the three layer architecture of the globe in terms of the retina, choroid, and the sclera could be visualized.

The beam-line BL-14C at the Photon Factory, a synchrotron at KEK (Tsukuba, Japan), with a 31keV vertically polarized, monochromatic and coherent X-rays was used for PCI. The XDFI systemused a system of Bragg- and Laue-case crystals in tandem, separated by the specimen on a rotating platform. The Laue-case analyzer splits the X-ray beam coming from the specimen into a forwardly diffracted beam (the Dark Field Image) and a separate diffracted beam (the Bright Field Image) which are captured by two CCD cameras. Using these two beams, acquired simultaneously, the attenuation and refraction-contrast projection images were computed. By rotating the specimen, these projection images were converted into computed tomography (CT) slice data. The specimens consisted of an enucleated eye and atherosclerotic plaque in segments of proximal aorta, iliac artery, and coronary artery. After imaging, the specimens were sectioned and histologically analyzed using standard stains and techniques.

Ando, M, Sunaguchi, N, Do, S, Wu, Y, Lee, S, Gupta, R, Schmitz, A, Yuasa, T, X-ray Phase Contrast Imaging in the Dark Field: Implementation and Preliminary Evaluation Using Tissue Specimens.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12037798.html