Magnetic resonance imaging (MRI) systems and methods to effect MRI data acquisition with reduced noise in fast spin echo (FSE) and spin echo (SE) implementations are described. The improved MRI data acquisition is performed by acquiring k-space data while maintaining a constant or near constant slice select gradient amplitude throughout a sequence kernel. The acquired k-space data can then be used to generate an MR image.

In a method and a control device for operating a magnetic resonance system by a pulse sequence that includes an excitation phase, material in an examination volume is excited by emission of an RF excitation pulse during a selection gradient pulse in a first gradient direction. RF refocusing pulses are then emitted and readout gradient pulses are activated in a second gradient direction for spatially coded acquisition of raw data of the examination volume along the second gradient direction. A prephasing gradient pulse is switched before a first RF refocusing pulse in the second gradient direction, and/or a rephaser gradient pulse is switched before an RF restore pulse, following the RF refocusing pulses, in the second gradient direction. The prephaser gradient pulse and/or the rephaser gradient pulse have lower slew rates than the readout gradient pulses.

Methods and systems for diagnosing a condition of a central nervous system are provided. A method includes providing a DBSI-MRI data set obtained from the central nervous system of the subject, and transforming the DBSI-MRI data set to obtain at least one DBSI biomarker value. The method further includes comparing each DBSI biomarker value to at least one corresponding threshold value from a diagnostic database to obtain a relation between each DBSI biomarker value and the at least one corresponding threshold value, and diagnosing the condition according to at least one diagnostic rule, wherein each diagnostic rule defines a candidate condition in terms of the relations between the at least one DBSI biomarker value and the at least one corresponding threshold value.

Techniques are disclosed for acquiring magnetic resonance data of an object with a magnetic resonance imaging apparatus. A slice group is imaged whose slices define a contiguous imaging volume and which contains a first number of slices. In a number of concatenations, the magnetic resonance data for subgroups of the slices, each containing a respective second number of slices depending on the first number of concatenations, are acquired, and shimming is performed to increase field homogeneity in the imaging volume. To define the subgroups, the imaging volume is subdivided into at least two disjoint contiguous sub-volumes, and at least two subgroups are defined for each sub-volume, each subgroup only containing non-adjacent slices in the sub-volume. During acquisition of the magnetic resonance data of each subgroup, shimming is at least restricted to the respective sub-volume.

A system and method for simultaneous multi-slice nuclear spin tomography is provided which requires no sensitivity profile of a receiving coil along a slice axis. A pulse space region to be sampled can be specified. A first pulse space dimension (k.sub.y) can be assigned to a first phase-encoded axis and a second pulse space dimension (k.sub.z) can be assigned to a second phase-encoded axis and the second phase-encoded axis corresponds to the slice axis. A sampling scheme can also be specified, and a complete sampled can be provided along the second pulse space dimension (k.sub.z). A magnetic resonance scan can then be carried out within the pulse space region to be sampled based on the sampling scheme and respective phase-encodings of the first and second phase-encoded axis.

In order to remove restriction on the number of additions in imaging for offsetting errors caused by hardware performance and/or signal fluctuation caused by a hardware control method by inverting the polarity of predetermined hardware output, the present invention executes a first imaging sequence and a second imaging sequence in which the polarity of a predetermined gradient magnetic field pulse in the first imaging sequence was inverted, adds data acquired in each imaging sequence, and then acquires addition images. In order to perform the addition, each coefficient is determined so that the total of coefficients by which first data acquired in the first imaging sequence are to be multiplied is equal to the total of coefficients by which second data acquired in the second imaging sequence are to be multiplied.

In a method and magnetic resonance (MR) apparatus for recording MR signals in a recording volume of an examination object with an imaging sequence, the recording volume has a first recording region in which at least one system component of the scanner of the MR apparatus has a first homogeneity, which is greater than a homogeneity of the at least one scanner component in a second recording region of the recording volume. A magnetization of nuclear spins in the recording volume is produced by at least one RF pulse, with the RF pulse being determined such that the magnetization produced in the first recording region by the at least one RF pulse is greater than magnetization produced in the second recording region by the at least one RF pulse.

In a method and apparatus for acquiring magnetic resonance (MR) raw data, an MR data acquisition scanner is operated to execute a turbo spin echo (TSE) or a turbo gradient spin echo (TGSE) sequence wherein nuclear spins are excited in multiple slices of the examination object simultaneously by radiating at least one radio-frequency (RF) pulse from an RF radiator of the MR data acquisition scanner, thereby causing the excited nuclear spins in said multiple slices to produce an echo train. A multi-band refocusing pulse is radiated that refocuses nuclear spins in at least one of said multiple slices that follows a first of the multiple slices, and readout gradients are activated to acquire MR signals, with respectively different contrasts, at respectively different readout times of the echo train. The read out MR signals are entered into an electronic memory organized as k-space.

Pulse sequences for an MRI apparatus can provide improved quantitative relaxometry in liver and other tissues. Relaxation parameters such as T1rho or T2 (or both at once) can be measured. The pulse sequence can include a magnetization preparation pulse sequence and an acquisition pulse sequence including a fast spin echo (FSE) pulse sequence. Flip angles and echo time for the FSE pulse sequence can be chosen to optimize image quality without affecting the quantification of a relaxation parameter. Additional pulse sequences, e.g., for enhanced blood suppression and/or fat suppression can be incorporated. The acquisition pulse sequence can have a duration that allows data for a single slice image to be acquired during a breath-hold.

In a method and a magnetic resonance system to acquire MR data of a slice of a volume segment within an examination subject, a slice selection gradient is activated along a first direction that is orthogonal to the slice. An RF excitation pulse is radiated for selective excitation of the slice, a first phase coding gradient is activated along the first direction, and a second phase coding gradient is activated along a second direction. The second direction is orthogonal to the first direction. A readout gradient is activated along a third direction that is orthogonal to the first direction and the second direction. MR data are acquired while the readout gradient is activated. A number of phase coding steps for the second phase coding gradient is determined depending on the first phase coding gradient.