100 results about "Saturation pulse" patented technology

A pulse sequence for time-of-flight (TOF) magnetic resonance angiography (MRA) includes a fatsat segment, a magnetization transfer segment, and a spatial saturation segment that are applied by an MR apparatus to acquire MR data for image reconstruction with improved image quality. The pulse sequence is constructed such that at the beginning of each iteration of the inner loop of a 3D acquisition, a fatsat pulse is applied. After the fatsat pulse, MR data is acquired in a series of imaging segments with well-suppressed fat signal. Effective fat suppression is achieved by sampling central k-space data first, before signal from fat relaxes back to a pre-saturation level. Each imaging segment is immediately preceded by one of a MT pulse or a spatial saturation pulse and immediately followed by the other one of the MT pulse or the spatial saturation pulse.

Before myocardium perfusion imaging, the variation of position in the dynamic time-phase direction due to a respiratory body motion of the subject is detected, and the slice excitation position and the data collection position are made to follow up the body motion according to the variation. For the follow-up, a saturation pulse of space nonselection and a local selection pulse for flip back of the flip angle attributed to the saturation pulse of space nonselection are applied to the region to which a probe pulse for detecting the body motion of the subject before the heart is imaged is applied before the probe pulse is applied, thereby measuring the body motion.

In imaging a first species having a short T2 magnetic resonance parameter in the presence of a second and third species having longer T2 parameters, a method of suppressing signals from the longer T2 species comprises the steps of: a) applying a RF saturation pulse with multiple suppression bands for the second and third species to excite nuclei spins of the longer T2 species with the magnitude of the RF pulse being sufficiently low so as not to excite nuclei spins of the short T2 species, the RF saturation pulse being sufficiently long to rotate the longer T2 species nuclei spins into a transverse plane, and b) dephasing the longer T2 species nuclei spins in the transverse plane. An imaging pulse sequence is then applied to image the short T2 species. Alternatively, the method can comprise the steps of a) applying a first inversion pulse for selective inverting species of the second longer T2 species, b) obtaining first image signals after step a, c) applying a second inversion pulse for selectively inverting species of the third longer T2 species, d) obtaining second image signals after step c), and e) combining the first image signals and the second image signal to image the first short T2 species with the longer second and third species cancelling in the combination. In each of these methods, either the second or third longer T2 species can be suppressed without suppressing the other by applying the RF saturation or inversion pulse only to the species to be suppressed.

A non-selective saturation pulse together with a series of notched RF saturation pulses are used to acquire MR perfusion data. The non-selective saturation recovery RF pulse is non-selective and is designed to be effective at blood pool suppression for a first slice as well as a next slice in a series of slice locations. The first slice. location may be placed at an angle or plane that is not necessarily coaxial with the other slice locations to be imaged. The present invention supports the acquisition of MR data with efficient spatial coverage and a calibration slice of data that provides a linear measure of signal intensity versus contrast concentration in a blood pool.

When performing imaging in synchronization with a biological movement of an examinee by using a pulse sequence applying a pre-saturation pulse, it is possible to reduce irregularities of echo signal intensity and artifact on the image generated by the irregularities. Especially, it is possible to prevent artifact attributed to blood in the ventricle when performing delay contrast imaging. For this, before measuring the echo signal, an IR pulse or the like for adjusting magnetization to a desired state is applied so as to suppress irregularities of the echo signal intensity and prevent artifact.

Saturation pulse sequences are designed to ensure complete saturation of nuclear spins for dual wait time measurements and saturation recovery measurements in the case of axial motion of a downhole NMR logging tool. Frequency and / or phase modulation may be used. An auxiliary saturation coil may be used.