University of Basel

Universitatsspital Basel

University Hospital of Basel

Siemens Healthcare Gmbh

Universitaetsspital Basel

Oliver Bieri

Klaus Scheffler

Grzegorz Bauman

Tobias Kober

Tom Hilbert

Gunnar Krueger

Orso Andrea Pusterla

Damien Nguyen

Rahel Heule

A method for the assessment of the lung parenchyma in a human or an animal is indicated using a series of magnetic resonance (MR) images of the lung parenchyma acquired at different breathing positions in the same human or animal. The method comprises at least the steps of a.) estimating a change of the lung volume Vbetween the different breathing positions, b.) determining a signal intensity SI({right arrow over (x)}) in at least one same region or position {right arrow over (x)}of the lung parenchyma for each of the MR images, and c.) determining at least one respiratory index &#x3b1;({right arrow over (x)}) according to the formula 

Assessment of the lung parenchyma by means of magnetic resonance images

A magnetic resonance imaging (MRI) method is provided in which a sample is subjected to a gradient echo imaging sequence having a plurality of basic sequence elements each of which includes a radiofrequency (RF) pulse, at least one frequency encoding gradient moment kfor generating a magnetic resonance (MR) signal, at least one first phase encoding gradient moment kfor phase encoding the MR signal and a data acquisition period during which k-space data reflecting the MR signal are acquired. The frequency encoding gradient moment kand the first phase encoding gradient moment kare applied such during the data acquisition period of each basic sequence element, that the k-space data are acquired in a radial direction and asymmetrically with respect to the center of k-space in the direction from the periphery towards the center of k-space.

Magnetic resonance imaging method with asymmetric radial acquisition of K-space data

A method for improving image homogeneity of image data acquired from balanced Steady-State Free Precision (bSSFP) sequences in magnetic resonance imaging. Multiple bSSFP sequences are performed with different radio frequency phase increments to create multiple bSSFP image volumes with different phase offsets &#x3d5;. Each image has voxels whose intensity M is a function of a nuclear resonance signal (or magnetization) measured by the MR imaging apparatus. Per-voxel fitting of a mathematical signal model onto the measured magnetization of the field of view in function of the phase offsets &#x3a6;. Then the spin density M, the relaxation time ratio &#x39b; and the local phase offset &#x394;&#x3a6; are determined from the fit for each voxel. A homogeneous image of the object is generated by calculating the signal intensity in each voxel, using the spin density Mand the relaxation time ratio &#x39b;, wherein &#x394;&#x3a6; is chosen such that &#x3a6;&#x2212;&#x394;&#x3a6;=0&#xb0;.

Apparatus and method for improving balanced steady-state free precision in magnetic resonance imaging

A magnetic resonance imaging (MRI) method for the quantification of the longitudinal (T) and/or transverse (T) relaxation times in a sample. According to the MRI method, a sample is subjected to an unbalanced steady state free precession (SSFP) sequence comprising a series of consecutive radiofrequency (RF) pulses. By means of the unbalanced SSFP sequence, a first order SSFP FID signal (F), a lowest order SSFP FID signal (F), and a lowest order SSFP Echo signal (F) are acquired. Based on the F-signal, the F-signal and the F-signal, the longitudinal (T) and/or transverse (T) relaxation times of the sample are determined.

[object Object]

Disclosed is a magnetic resonance method for the quantification of molecular diffusion. The method uses a diffusion-weighted (dw) double echo steady state sequence (DESS). In particular, the method allows direct quantification of molecular diffusion from two steady state scans with differing diffusion weighting such as one with diffusion-weighting and preferably one without diffusion weighting. Such a quantification of molecular diffusion allows for rapid and/or quantitative measurements of physiological and/or functional parameters of living tissue. Quantitative measurements are often a prerequisite for pre-clinical and clinical research as well as for clinical trials in drug research performed at different sites. Especially for the early diagnosis of subtle or diffuse pathological changes, quantitative MR promises to have a very significant impact.

Magnetic resonance method for quantification of molecular diffusion using double echo steady state sequences

Apparatus and methods for quantification of transverse relaxation times (T) using steady-state free precession sequences (generally known as fast imaging sequences) and their sensitivity to a quadratic increase of the RF pulse phase, also known as RF spoiling. Using at least two image acquisitions with different partial RF spoiling increments, Tcan be assessed with high precision and with short acquisition times in the limit of large excitation angles being independent on the longitudinal relaxation time (T) and magnetization transfer effects as compared to other SSFP based quantitative Tmethods. This invention is not restricted to any kind of target and may be applied in 3D as well as in 2D.

Magnetic resonance method for quantification of transverse relaxation times

Apparatus and methods for modification of the frequency response profile of steady-state free precession (SSFP) type of magnetic resonance imaging (MRI) sequences. Using alternating dephasing moments within succeeding radiofrequency (RF) excitation pulses, the frequency response function of SSFP sequences can be modified to different shapes such as near triangular or bell shaped. The particular response function as produced by alternating dephasing moments can be used, among others, for functional brain MRI, MR spectroscopy or spatial encoding.

Modification of frequency response profiles of steady state free precession for magnetic resonance imaging (MRI)

Disclosed are methods and apparatuses for generating susceptibility-related contrast images, as induced, e.g., by marker material interventional devices used for passive MR-guided interventions, or by particles or cells loaded with marker materials used for molecular imaging, cell-tracking or cell-labeling. Near a local magnetic field perturber a positive contrast signal emanates from local gradient compensation to form, e.g., a balanced SSFP type of echo, whereas everywhere else echoes are shifted outside of the data acquisition window.

Magnetic resonance non-balanced-SSFP method for the detection and imaging of susceptibility related magnetic field distortions

Apparatus and methods of generating magnetization transfer contrast images in which signal to noise ratios are improved and/or in which image acquisition times are reduced. In certain embodiments, apparatus and methods which utilize sensitivity and/or non-sensitivity to magnetization transfer effects to improve the contrast of images which are generated. In certain additional embodiments, apparatus and methods for generating magnetization transfer contrast images which exhibit sensitivity to longitudinal and transverse relaxation times of bound and free proton pools, respectively.

Method and apparatus for generation of magnetization transfer contrast in steady state free precession magnetic resonance imaging

A method of nuclear magnetic resonance (NMR) imaging is proposed for the rapid detection of oscillatory motion of spins or charged particles to generate shear waves or oscillating electrical currents to induce alternating magnetic fields to the object being imaged, subjected to a fast train of radio-frequency (RF) pulses to induce within the sample a steady-state NMR signal. A scan using an NMR imaging system is carried out with a RF repetition time (TR) matched to the externally imposed oscillatory motion. Small oscillatory displacements of spins in combination with imaging gradients or oscillating magnetic fields related to charge motion generating alternating spin phase dispersions during the rf pulse train disturb the steady-state magnetization. Depending on the amount of spin-phase dispersion, the amplitude and phase of the NMR signals are modulated, generating a brightness-modulation of the reconstructed phase and amplitude images revealing mechanical or electrical properties of the object, such as stiffness or electrical impedance.

Method for detection and imaging of synchronous spin and charged particle motion

A method of steady-state free precession MR imaging is provided that includes the steps of: (a) providing a balanced steady-state free precession imaging sequence that includes a plurality of phase encoding steps, wherein each phase encoding step comprises a phase encoding gradient and a slice selection gradient; and (b) acquiring imaging data by performing the plurality of phase encoding steps in sequence, wherein the imaging data is acquired is compensated for one or more effects due to eddy-currents, flow, or motion related artefacts due to the implementation of one or more artefact compensation strategies that consist of (i) 'pairing' of consecutive phase encoding steps and of (ii) 'through slice equilibration' of eddy-current and motion or flow related signal oscillations.

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Liestal, Switzerland

Oliver Bieri