Cardiovascular magnetic resonance (CMR) phase contrast imaging has undergone a wide range of changes with the development and availability of improved calibration procedures, visualization tools, and analysis methods. This article provides a comprehensive review of the current state-of-the-art in CMR phase contrast imaging methodology, clinical applications including summaries of past clinical performance, and emerging research and clinical applications that utilize today’s latest technology.

In grating-based x-ray phase sensitive imaging, dark-field contrast refers to the extinction of the interference fringes due to small-angle scattering. For configurations where the sample is placed before the beamsplitter grating, the dark-field contrast has been quantified with theoretical wave propagation models. Yet when the grating is placed before the sample, the dark-field contrast has only been modeled in the geometric optics regime. Here we attempt to quantify the dark-field effect in the grating-before-sample geometry with first-principle wave calculations and understand the associated particle-size selectivity. We obtain an expression for the dark-field effect in terms of the sample material’s complex refractive index, which can be verified experimentally without fitting parameters. A dark-field computed tomography experiment shows that the particle-size selectivity can be used to differentiate materials of identical x-ray absorption.

We describe an x-ray differential phase-contrast imaging method based on two-dimensional transmission gratings that are directly resolved by an x-ray camera. X-ray refraction and diffraction in the sample lead to variations of the positions and amplitudes of the grating fringes on the camera. These effects can be quantified through spatial harmonic analysis. The use of 2D gratings allows differential phase contrast in several directions to be obtained from a single image. When compared to previous grating-based interferometry methods, this approach obviates the need for multiple exposures and separate measurements for different directions and thereby accelerates imaging speed.

Presents a new imaging method based on the classical Hall effect (HE), which describes the origin of a detectable voltage from a conductive object moving in a magnetic field. HE images are formed using ultrasound imaging techniques in a magnetic field. These images reflect the electrical properties of the sample. To demonstrate the feasibility of this method, images of plastic and biological samples are collected. The contrast mechanism and signal-to-noise issues are discussed. Since electrical parameters vary widely among tissue types and pathological states, HE imaging may be a useful tool for biological research and medical diagnosis.

Overlaying two transparent phase masks in a light beam results in a far-field achromatic intensity pattern. This effect lies at the basis of a polychromatic far-field interferometer for use in X-ray phase-contrast imaging without absorption gratings. A moiré pattern results from superimposing two black-and-white or greyscale patterns of regular geometry, such as two sets of evenly spaced lines. Here, we report the observation of an analogous effect with two transparent phase masks put in a light beam. The phase moiré effect and the classic moiré effect are shown to be the two ends of a continuous spectrum. The former allows the detection of sub-resolution intensity or phase patterns with a transparent screen. When applied to X-ray imaging, it enables the realization of a polychromatic far-field interferometer (PFI) without the need for absorption gratings. X-ray interferometry can non-invasively detect refractive index variations inside an object1,2,3,4,5,6,7,8,9,10. Current bench-top interferometers operate in the near field with limitations in sensitivity and X-ray dose efficiency2,5,7,8,9,10. The universal moiré effect helps overcome these limitations and obviates the need for using hard X-ray absorption gratings with sub-micrometre periods.