ontoneurolog-mr-dataset-acquisition.owl
type: Ontology
contributor: Farooq Ahmad, Michel Dojat, Bernard Gibaud, Pascal Girard, Gilles Kassel, Lynda Temal, bernard.gibaud@univ-rennes1.fr
date: 2010-07-14
imports: dataset.owl
imports: study-examination-subject.owl

AC-PC-line-orientation-at-acquisition
type: Class
subclass of: axis-orientation-at-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: AC-PC-line
disjoint with: bi-callosal-line-orientation-at-acquisition
disjoint with: central-sulcus-line-orientation-at-acquisition
disjoint with: lateral-sulcus-line-orientation-at-acquisition
definition: An AC-PC line orientation at acquisition is an axis orientation at acquisition that is parallel to a line underlining the Anterior Commissure and the Posterior Commissure. More precisely, this line is tangent to the superior part of the Anterior Commissure, and tangent to the inferior part of the Posterior Commissure. This line is also called “bi-commissural line”.

BOLD-sequence
type: Class
subclass of: MR-sequence
definition: Blood Oxygenation Level Dependent sequences are used for functional neuroimaging. These sequences are sensitive to magnetic inhomogeneities related to the presence of deoxy-hemoglobine (endogeneous paramagnetic agent). Generally GRE-EPI is used. Example: PRESTO (Principle of Echo Shifting with a Train of Observations) SEQUENCES are examples of BOLD SEQUENCES.

H-nucleus
type: Class
subclass of: nucleus
subclass of: Restriction
  on property: has-for-name
  has value: http://neurolog.unice.fr/ontoneurolog/v3.0/ontoneurolog-mr-dataset-acquisition.owl#H
definition: A 1H nucleus is a nucleus of an atom of hydrogen.

H1-chemical-shift-imaging-spectroscopy-sequence
type: Class
subclass of: spectroscopy-sequence
definition: H1 Chemical Shift Imaging (CSI) consists in recording the spectroscopic data, of the hydrogen nucelus for a group of voxels, in slice(s) (2D) or by volume (3D). The number and direction of phase encodings depend on the number of dimensions explored (1D, 2D or 3D), adding on to acquisition time. The results appear in the form of parametric images («metabolic maps ») or a matrix of the spectra of the regions to be studied. Examples: 2DCSI (Bi-dimensional Chemical Shift Imaging) SEQUENCES are examples of H1 CHEMICAL SHIFT IMAGING SPECTROSCOPY SEQUENCES. 3DCSI (Three-dimensional Chemical Shift Imaging) SEQUENCES are examples of H1 CHEMICAL SHIFT IMAGING SPECTROSCOPY SEQUENCES.

H1-single-voxel-spectroscopy-sequence
type: Class
subclass of: spectroscopy-sequence
definition: This sequence focuses on the spectroscopy of the hydrogen nucleus, where the signal received is limited to a single voxel. Examples: PRESS (point resolved spatial selection) SEQUENCES are examples of H1 SINGLE VOXEL SPECTROSCOPY SEQUENCES. STEAM (STimulated Echo Acquisition Mode) SEQUENCES are examples of H1 SINGLE VOXEL SPECTROSCOPY SEQUENCES.

MR-dataset-acquisition
type: Class
subclass of: dataset-acquisition
subclass of: Restriction
  on property: has-for-instrument-at
  on class: planned-acquisition-MR-protocol
  qualified cardinality: 1
subclass of: Restriction
  on property: has-for-instrument-at
  some values from: MR-equipment
subclass of: Restriction
  on property: has-for-result-at
  some values from: MR-dataset
subclass of: Restriction
  on property: has-for-instrument-at
  on class: MR-sequence
  qualified cardinality: 1

MR-image-contrast
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: MR-dataset
  qualified cardinality: 1
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
definition: [DEF & CIT] (Hornak, 2006, chapt. 8): “In order for pathology or any tissue for that matter to be visible in a magnetic resonance image there must be contrast or a difference in signal intensity between it and the adjacent tissue. The signal intensity, S, is determined by the signal equation for the specific pulse sequence used. Some of the intrinsic variables are the: Spin-Lattice Relaxation Time (T1), Spin-Spin Relaxation Time (T2), Spin Density (PD), T2*”. [SA] MR IMAGE CONTRASTS are divided among T1 CONTRASTS, T2 CONTRASTS, SPIN DENSITY CONTRASTS, and T2* CONTRASTS according to the variables to which the contrast is based.

MR-protocol
type: Class
subclass of: protocol
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
subclass of: Restriction
  on property: allows-to-carry-out
  some values from: MR-dataset-acquisition
definition: A MR PROTOCOL is a specification of actions to perform a MR DATASET ACQUISITION. [SA] MR PROTOCOLS are divided among PLANNED ACQUISITION MR PROTOCOLS and PERFORMED ACQUISITION MR PROTOCOLS according to whether the MR PROTOCOL refers to a class of planned MR DATASET ACQUISTIONS or to an individual performed MR DATASET ACQUISITION.

MR-sequence
type: Class
subclass of: protocol
subclass of: Restriction
  on property: allows-to-carry-out
  some values from: MR-dataset-acquisition
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
definition: A MR SEQUENCE specifies 3 basic components: (1) RF pulses that result in the magnetic resonance phenomenon, (2) gradients that enable the spatial encoding (in 2D or 3D) that will determine the way the k-space will be filled, and (3) signal reading that may combine one or more echo types (e.g. spin-echo, gradient echo). Besides, a MR SEQUENCE may be complemented with additional RF pulses, gradients or reconstruction methods, in order to: (1) modify contrast (e.g. preparation of magnetization by inversion recovery, fat saturation, magnetization transfer); (2) speed up the sequence (partial filling of Fourier space, parallel acquisition, rapid recovery of magnetization); (3) minimize artefacts.

P-nucleus
type: Class
subclass of: nucleus
subclass of: Restriction
  on property: has-for-name
  has value: http://neurolog.unice.fr/ontoneurolog/v3.0/ontoneurolog-mr-dataset-acquisition.owl#P
definition: A 31P nucleus is a nucleus of an atom of phosphorus.

T1-contrast
type: Class
subclass of: MR-image-contrast
subclass of: Restriction
  on property: has-for-name
  has value: T1
disjoint with: T2-contrast
disjoint with: spin-density-contrast
definition: A T1 CONTRAST is a MR IMAGE CONTRAST which is predominantly caused by differences in T1 (the Spin-Lattice Relation Time), of the tissues.

T2-contrast
type: Class
subclass of: MR-image-contrast
subclass of: Restriction
  on property: has-for-name
  has value: T2
disjoint with: spin-density-contrast
definition: A T2 CONTRAST is a MR IMAGE CONTRAST which is predominantly caused by differences in T2 (the Spin-Spin Relation Time), of the tissues.

T2-star-contrast
type: Class
subclass of: MR-image-contrast
subclass of: Restriction
  on property: has-for-name
  has value: T2-star
definition: A T2* CONTRAST is a MR IMAGE CONTRAST which is predominantly caused by differences in T2*, of the tissues.

acquisition-contrast-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: MR-image-contrast
  qualified cardinality: 1

acquisition-resolution-in-x
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: dataset
  qualified cardinality: 1
definition: The ACQUISITION RESOLUTION IN X is the “dimensions of the acquired frequency/phase data before reconstruction: acquisition resolution in x is frequency columns” [DICOM Standard, Part 3].

acquisition-resolution-in-x-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: acquisition-resolution-in-x
  qualified cardinality: 1

acquisition-resolution-in-y
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: dataset
  qualified cardinality: 1
definition: The ACQUISITION RESOLUTION IN Y is the “dimensions of the acquired frequency/phase data before reconstruction: acquisition resolution in y is phase rows” [DICOM Standard, Part 3].

acquisition-resolution-in-y-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: acquisition-resolution-in-y
  qualified cardinality: 1

acquisition-with-magnetization-transfer
type: Class
subclass of: radio-frequency-signal-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: with-magnetization-transfer
definition: A magnetization transfer pulse is inserted in order to change the contrast property in the image.

acquisition-without-magnetization-transfer
type: Class
subclass of: radio-frequency-signal-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: without-magnetization-transfer
definition: No magnetization transfer pulse is inserted.

angiography-sequence
type: Class
subclass of: MR-sequence
definition: Angiography sequences are used to assess vascular information.

axis-orientation-at-acquisition
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: dataset
  qualified cardinality: 1
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
definition: For dataset acquisition, the acquired volume can be oriented following a specific axis, e.g the AC-PC line or the bi-callosal-line. Axis orientation denotes the position of the chosen axis.

axis-orientation-at-acquisition-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: axis-orientation-at-acquisition
  qualified cardinality: 1

bi-callosal-line-orientation-at-acquisition
type: Class
subclass of: axis-orientation-at-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: bi-callosal-line
disjoint with: central-sulcus-line-orientation-at-acquisition
disjoint with: lateral-sulcus-line-orientation-at-acquisition
definition: A bi-callosal line orientation at acquisition is an axis orientation at acquisition that is parallel to the line underlining the rostrum and splenium of the corpus callosum.

body-coil
type: Class
subclass of: coil
subclass of: Restriction
  on property: has-for-type-name
  has value: body
definition: A BODY COIL is a large coil covering the entire body.

calibration-sequence
type: Class
subclass of: MR-sequence
definition: Calibration sequences are used to assess specific parameters of the scanner (stability over time, B0 inhomogeneity, etc.)

central-sulcus-line-orientation-at-acquisition
type: Class
subclass of: axis-orientation-at-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: central-sulcus-line
disjoint with: lateral-sulcus-line-orientation-at-acquisition
definition: A central sulcus line orientation at acquisition is an axis orientation at acquisition that is parallel to a line approximating the mean direction of the central sulcus.

coil
type: Class
subclass of: physical-object
subclass of: manufactured-object
subclass of: Restriction
  on property: has-for-model-name
  on class: model-name
  qualified cardinality: 1
subclass of: Restriction
  on property: has-for-name
  some values from: name
subclass of: Restriction
  on property: has-for-type-name
  some values from: name
definition: A COIL is a wound spiral of two or more turns of insulated wire, used to introduce inductance into a circuit. [SA] COILS are divided among RECEIVING COILS and TRANSMITTING COILS according to whether their function is to receive or to transmit a signal. [SA] COILS are divided among BODY COILS, HEAD COILS and SURFACE COILS according to their corresponding geometry: body for whole body coil, head for volumic head coil and surface for surfacic coil. Note that only the major types of coils used for brain studies are represented. [SA] COILS are divided among ONE-CHANNEL COILS and MULTI-CHANNEL COILS according to the corresponding number of channels associated to the coil.

coil-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: coil
  qualified cardinality: 1

contrast-agent
type: Class
subclass of: amount-of-matter
subclass of: manufactured-object
subclass of: technical-artefact
subclass of: Restriction
  on property: has-for-model-name
  on class: model-name
  qualified cardinality: 1
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
subclass of: Restriction
  on property: allows-to-carry-out
  some values from: dataset-acquisition
definition: Contrast agents are used during medical imaging examinations to highlight specific parts of the body and make them easier to see. Contrast agents can be used with many types of imaging examinations, including x-ray exams, computed tomography scans and magnetic resonance imaging. [DIV] Every CONTRAST AGENT has for name the name of the chemical element used.

contrast-agent-angio-sequence
type: Class
subclass of: angiography-sequence
definition: A contrast agent, generally Gadolinium, is injected to improve the signal-to-noise ratio. Example: TRICK (Time Resolved Imaging on Contrast Kinetics) SEQUENCES are examples of CONTRAST AGENT ANGIO SEQUENCES.

contrast-agent-concentration
type: Class
subclass of: concentration
subclass of: Restriction
  on property: is-a-quality-of
  on class: contrast-agent
  qualified cardinality: 1

contrast-agent-concentration-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: contrast-agent-concentration
  qualified cardinality: 1

contrast-agent-used-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: contrast-agent
  qualified cardinality: 1

contrast-agent-volume
type: Class
subclass of: volume
subclass of: Restriction
  on property: is-a-quality-of
  on class: contrast-agent
  qualified cardinality: 1

contrast-agent-volume-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: contrast-agent-volume
  qualified cardinality: 1

conventional-cartesian-MR-sequence
type: Class
subclass of: MR-sequence
disjoint with: non-conventional-MR-sequence
definition: A CONVENTIONAL CARTESIAN MR SEQUENCE is a MR SEQUENCE in which “the geometry of k-space traversal is rectilinear” [DICOM Standard, 2008] and in which “only one line of k-space is acquired after the single 180° refocusing pulse in each TR period.” [Boyle et al., 2006]

coronal-slice-orientation-at-acquisition
type: Class
subclass of: slice-orientation-at-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: coronal
definition: if (Row= Head-Foot and Column= Right-Left) or (Row= Right-Left and Column= Head-Foot).

dataset-acquisition-equipment
type: Class
subclass of: manufactured-object
subclass of: Restriction
  on property: allows-to-carry-out
  some values from: dataset-acquisition
subclass of: Restriction
  on property: has-for-model-name
  on class: model-name
  qualified cardinality: 1
subclass of: Restriction
  on property: has-for-serial-number
  on class: serial-number
  qualified cardinality: 1

diffusion-b-value
type: Class
subclass of: physical-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: diffusion-gradient
  qualified cardinality: 1
definition: “In diffusion imaging, the image-intensities at each position are attenuated, depending on the strength (b-value) and direction of the so-called magnetic diffusion gradient, as well as on the local microstructure in which the water molecules diffuse. The more attenuated the image is at a given position, the greater diffusion there is in the direction of the diffusion gradient. In order to measure the tissue's complete diffusion profile, one needs to repeat the MR scans, applying different directions (and possibly strengths) of the diffusion gradient for each scan”. (from Wikipedia). B-values are expressed in sec/mm2.

diffusion-b-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: diffusion-b-value
  qualified cardinality: 1

diffusion-gradient
type: Class
subclass of: physical-object
definition: “Diffusion MRI is a magnetic resonance imaging (MRI) method that produces in vivo images of biological tissues weighted with the local microstructural characteristics of water diffusion. The field of diffusion MRI can be understood in terms of two distinct classes of application—diffusion weighted MRI and diffusion tensor MRI. In order to obtain an image weighted in diffusion of water molecules, specific magnetic field gradients (called diffusion gradients) are introduced in several directions. For diffusion-weighted imaging (DWI), three gradient-directions are applied, sufficient to estimate the trace of the diffusion tensor or 'average diffusivity'. Clinically, trace-weighted images have proven to be very useful to diagnose vascular strokes in the brain, by early detection (within a couple of minutes) of the hypoxic edema”. (from Wikipedia)

diffusion-gradient-orientation
type: Class
subclass of: physical-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: diffusion-gradient
  qualified cardinality: 1
definition: Defines the orientation of the applied diffusion gradient. Orientation is represented by a vector, defined in the scanner spatial referential.

diffusion-gradient-orientation-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: diffusion-gradient-orientation
  qualified cardinality: 1

diffusion-sequence
type: Class
subclass of: MR-sequence
definition: DW-MRI aims at highlighting the differences in water molecule mobility, irrespective of their direction of displacement. It focuses on the micromovements (random, brownian) of the water molecules inside voxels. These motions encounter different obstacles in the body (cell membranes, proteins, macromolecules, fibers…), which vary according to the tissues and certain pathological modifications (intracellular edema, abscess, tumors…). Essentially, extracellular water is the main object of exploration in diffusion imaging. Diffusion data provides indirect information about the structure surrounding these water molecules. Diffusion tensor MRI, on the other hand, studies the directions of water molecule motion to determine, for example, whether or not they diffuse in all directions (fractional anisotropy), or attempts to render the direction of a particular diffusion (which can be applied to indirectly reconstituting the nerve fiber trajectory). (from http://www.e-mri.org). Examples: DWISE (Diffusion Weighted Imaging Spin Echo) SEQUENCES are examples of DIFFUSION SEQUENCES. DW EPI (Diffusion Weighted Echo Planar Imaging) SEQUENCES are examples of DIFFUSION SEQUENCES. PRO SEQUENCES are examples of DIFFUSION SEQUENCES.

echo-time
type: Class
subclass of: temporal-quality
definition: The ECHO time is the “time in ms between the middle of the excitation pulse and the peak of the echo produced (kx=0). In the case of segmented k-space, the TE(eff) is the time between the middle of the excitation pulse to the peak of the echo that is used to cover the center of k-space (i.e. kx=0, ky=0)” [DICOM Standard, Part 3].

echo-time-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: echo-time
  qualified cardinality: 1

feet-first-decubitus-left-patient-position
type: Class
subclass of: patient-position
subclass of: Restriction
  on property: has-for-name
  has value: feet-first-decubitus-left
definition: The patient is entered in the magnet feet first lying on the left side.

feet-first-decubitus-right-patient-position
type: Class
subclass of: patient-position
subclass of: Restriction
  on property: has-for-name
  has value: feet-first-decubitus-right
definition: The patient is entered in the magnet feet first lying on the right side .

feet-first-prone-patient-position
type: Class
subclass of: patient-position
subclass of: Restriction
  on property: has-for-name
  has value: feet-first-prone
definition: The patient is entered in the magnet feet first lying down with the face down.

feet-first-supine-patient-position
type: Class
subclass of: patient-position
subclass of: Restriction
  on property: has-for-name
  has value: feet-first-supine
definition: The patient is entered in the magnet feet first lying down with the face up .

field-of-view
type: Class
subclass of: dependent-place
definition: A FIELD OF VIEW is the image area that contains the object to measure.

field-of-view-in-x
type: Class
subclass of: physical-quality
definition: Field of view in X defines the size in the X direction expressed generally in mm.

field-of-view-in-x-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: field-of-view-in-x
  qualified cardinality: 1

field-of-view-in-y
type: Class
subclass of: physical-quality
definition: Field of view in Y defines the size in the Y direction expressed generally in mm

field-of-view-in-y-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: field-of-view-in-y
  qualified cardinality: 1

flip-angle
type: Class
subclass of: physical-quality
definition: A FLIP ANGLE is a “steady state angle in degrees to which the magnetic vector is flipped from the magnetic vector of the primary field” [DICOM Standard, Part 3].

flip-angle-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: flip-angle
  qualified cardinality: 1

gradient-echo-sequence
type: Class
subclass of: MR-sequence
definition: “These sequences use a gradient to generate an RF echo, rather than a 180° refocusing pulse, as is the case in spin-echo sequences. Gradient-echo sequences generally use an excitation flip angle of less than 90°. Gradient-echo sequences allow faster imaging than spin-echo sequences and are frequently used in fast 3D imaging. The echo peak of a gradient echo lies on a T2* curve, rather than on a T2 curve as in spin-echo imaging. Since the T2* value of tissue is sensitive to variations in magnetic field strength, gradient-echo images are sensitive to factors perturbing the static field. A benefit of this is good sensitivity to haemorrhagic lesions, since magnetic susceptibility is disturbed by haemoglobin degradation products.” [Boyle et al., 2006].

head-coil
type: Class
subclass of: coil
subclass of: Restriction
  on property: has-for-type-name
  has value: head
definition: A HEAD COIL is a coil restricted to the head volume.

head-first-decubitus-left-patient-position
type: Class
subclass of: patient-position
subclass of: Restriction
  on property: has-for-name
  has value: head-first-decubitus-left
definition: The patient is entered in the magnet head first lying on the left side.

head-first-decubitus-right-patient-position
type: Class
subclass of: patient-position
subclass of: Restriction
  on property: has-for-name
  has value: head-first-decubitus-right
definition: The patient is entered in the magnet head first lying on the right side.

head-first-prone-patient-position
type: Class
subclass of: patient-position
subclass of: Restriction
  on property: has-for-name
  has value: head-first-prone
definition: The patient is entered in the magnet head first lying down with the face down.

head-first-supine-patient-position
type: Class
subclass of: patient-position
subclass of: Restriction
  on property: has-for-name
  has value: head-first-supine
definition: The patient is entered in the magnet head first lying down with the face up.

hybrid-gradient-echo-and-spin-echo-sequence
type: Class
subclass of: multi-echo-gradient-echo-sequence
subclass of: multi-echo-spin-echo-sequence
definition: “This is a hybrid sequence that brings together features of RARE (i.e. Multi-echo Spin Echo) and EPI sequences. As in RARE, multiple 180° pulses are used to generate multiple spin echoes from an initial excitation pulse. In addition, multiple gradient echoes are generated by gradient switching after each 180° pulse. This allows several lines of k space to be filled per refocusing pulse… Fast sequence mainly used for T2-weighted imaging. Improved resolution relative to RARE for a given imaging time. Less image distortion than in EPI. Can be used to give improved T2*-weighted imaging compared to RARE and hence better sensitivity to hemorrhagic lesions. RARE imaging gives unusually bright fat, whereas fat appearance in GRASE/TurboGSE imaging is more like that in conventional spin-echo imaging. The short inter–180° pulse spacing in RARE causes the fat-brightening effect; in GRASE/TurboGSE, this spacing can be longer, as multiple lines of k-space are filling after each 180° pulse. The longer gap between 180° pulses in GRASE/TurboGSE results in a lower specific absorption rate.” [Boyle et al., 2006] Examples TurboGSE (turbo gradient spin echo) is an example of HYBRID GRADIENT-ECHO AND SPIN-ECHO SEQUENCE provided by Siemens Medical Solutions. GRASE (gradient echo and spin echo) is an example of HYBRID GRADIENT-ECHO AND SPIN-ECHO SEQUENCE provided by both Philips Medical Systems and GE Medical Systems.

imaged-nucleus
type: Class
subclass of: nucleus
definition: An IMAGED NUCLEUS is a NUCLEUS that is resonant at the IMAGING FREQUENCY.

imaged-nucleus-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: imaged-nucleus
  qualified cardinality: 1

imaging-frequency
type: Class
subclass of: temporal-quality
definition: The IMAGING FREQUENCY is the radio frequency (MHz) set on the scanner that corresponds to the precession frequency of the nucleus considered under the existing magnetic field.

imaging-frequency-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: imaging-frequency
  qualified cardinality: 1

interlaced-even-acquired-first-slice-order
type: Class
subclass of: slice-order
subclass of: Restriction
  on property: has-for-name
  has value: interlaced-even-acquired-first
definition: Slices are interlaced: the even slices are acquired first then the odd slices.

interlaced-odd-acquired-first-slice-order
type: Class
subclass of: slice-order
subclass of: Restriction
  on property: has-for-name
  has value: interlaced-odd-acquired-first
definition: Slices are interlaced: the odd slices are acquired first then the even slices.

inversion-recovery-segmented-spin-echo-sequence
type: Class
subclass of: segmented-spin-echo-sequence
definition: An INVERSION RECOVERY SEGMENTED SPIN-ECHO SEQUENCE uses an inversion recovery. Examples: TurboSTIR (Turbo Short Tau Inversion Recovery), turboFLAIR (Turbo FLuid-Attenuated Inversion Recovery), Turbo IR (Turbo Inversion Recovery), FastFlair (Fast FLuid-Attenuated Inversion Recovery), IR FastSE (Inversion Recovery Fast Spin Echo), Fast SE STIR (Fast Spin Echo - Short Tau Inversion Recovery) are examples of INVERSION RECOVERY SEGMENTED SPIN-ECHO SEQUENCES. We treat them as names for such SEQUENCES.

inversion-recovery-single-echo-spin-echo-sequence
type: Class
subclass of: single-echo-spin-echo-sequence
definition: An INVERSION RECOVERY SINGLE-ECHO SPIN-ECHO SEQUENCE involves an inversion recovery single echo spin echo sequence. “The term inversion recovery refers to a class of sequences that begin each TR with an inverting 180° RF pulse. After a delay TI (the inversion time), a host sequence is initiated. The host sequence may be one of several sequence types. The longitudinal magnetization at the start of the host sequence is determined by the degree of recovery of the inverted magnetization. Contrast in an IR image is strongly influenced by TI and tissue T1 (i.e., the image is T1-weighted).” [Boyle et al., 2006]. Examples: FLAIR (fluid attenuated inversion recovery), IR (true inversion recovery), IRM (inversion recovery utilizing only the magnitude), and STIR (short tau inversion recovery) are examples of INVERSION RECOVERY SINGLE-ECHO SPIN-ECHO SEQUENCES. We treat them as names for such SEQUENCES.

inversion-recovery-single-shot-spin-echo-sequence
type: Class
subclass of: single-shot-spin-echo-sequence
definition: An INVERSION RECOVERY SINGLE-SHOT SPIN-ECHO SEQUENCE uses an inversion recovery as preparation phase. Examples: HASTIRM (Half-Fourier acquired single-shot turbo inversion recovery technique utilizing the magnitude information) and IR RARE (Inversion Recovery - Rapid Acquisition with Relaxation Enhancement) are examples of INVERSION RECOVERY SINGLE-SHOT SPIN-ECHO SEQUENCES. We treat them as names for such SEQUENCES.

inversion-time
type: Class
subclass of: temporal-quality
definition: The INVERTION TIME is the “time in msec after the middle of inverting RF pulse to middle of excitation pulse to detect the amount of longitudinal magnetization (concerns only sequences with inversion recovery)” [DICOM Standard, Part 3].

inversion-time-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: inversion-time
  qualified cardinality: 1

lateral-sulcus-line-orientation-at-acquisition
type: Class
subclass of: axis-orientation-at-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: lateral-sulcus-line
definition: A lateral sulcus line orientation at acquisition is an axis orientation at acquisition that is parallel to a line approximating the mean direction of the lateral sulcus.

magnetization-prepared-gradient-echo-sequence
type: Class
subclass of: single-echo-gradient-echo-sequence
definition: “Gradient-echo sequences that acquire an image in less than a second are considered ultrafast sequences. Achieving adequate signal and contrast in a simple very short TE, very short TR gradient-echo sequence is a problem; for good T1 contrast, a larger flip angle is needed, but the optimal flip angle for a good signal-to-noise ratio (SNR) (ie, the Ernst angle) at short TRs is small. Ultrafast sequences overcome this problem by incorporating a magnetization preparation phase prior to the gradient-echo host. Typically, a 180° RF pulse is applied in the preparatory phase. The 180° flip introduces increased T1 weighting. All lines in k-space are acquired after this single preparatory pulse used for high-speed T1-weighted imaging.” [Boyle et al., 2006] Examples: TFE (turbo field echo) is an example of MAGNETIZATION PREPARED GRADIENT-ECHO SEQUENCE provided by Philips Medical Systems. We treat TFE as a name for such SEQUENCES.

magnetization-prepared-segmented-gradient-echo-echo-planar-imaging-sequence
type: Class
subclass of: segmented-gradient-echo-echo-planar-imaging-sequence
definition: uses a magnetization preparation.

magnetization-prepared-single-shot-gradient-echo-echo-planar-imaging-sequence
type: Class
subclass of: single-shot-gradient-echo-echo-planar-imaging-sequence
definition: uses a magnetization preparation Example: IR-EPI (Inversion Recoverery Echoplanar imaging) and DW-EPI (Diffusion Weighted Echoplanar imaging) are examples of MAGNETIZATION PREPARED SINGLE-SHOT GRADIENT-ECHO - ECHO PLANAR IMAGING SEQUENCES.

magnetization-prepared-spoiled-gradient-echo-sequence
type: Class
subclass of: magnetization-prepared-gradient-echo-sequence
subclass of: spoiled-gradient-echo-sequence
definition: This sequence combines a magnetization phase with a spoiled gradient-echo. This sequence gives a good contrast to noise ratio between tissues essential for morphometry studies. Examples: MP RAGE (Magnetization Prepared Rapid Gradient Echo) is an example of MAGNETIZATION PREPARED-SPOILED GRADIENT-ECHO SEQUENCE provided by Siemens Medical Solutions. TurboFLASH is an example of MAGNETIZATION PREPARED-SPOILED GRADIENT-ECHO SEQUENCE provided by Siemens Medical Solutions. Fast SPGR (spoiled gradient recalled acquisition in steady-state) is an example of MAGNETIZATION PREPARED-SPOILED GRADIENT-ECHO SEQUENCE provided by GE Medical Systems. MDEFT (Modified Driven Equilibrium Fourier Transform) is an example of MAGNETIZATION PREPARED-SPOILED GRADIENT-ECHO SEQUENCE provided by Bruker.

magnetization-transfer-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: radio-frequency-signal-acquisition
  qualified cardinality: 1

morphometry-sequence
type: Class
subclass of: MR-sequence
definition: Morphometry sequences are used to assess morphometric information about the image object. For instance MPRAGE sequences are generally used to obtain a good contrast between tissues and then to segment grey matter, white matter or lesion and report about their respective quantity. Examples: MP-RAGE (Magnetization-Prepared RApid Gradient-Echo) SEQUENCES are examples of MORPHOMETRY SEQUENCES. FSPGR (Fast SPoiled Gradient-Recalled acquisition in the steady state) SEQUENCES are examples of MORPHOMETRY SEQUENCES.

multi-channel-coil
type: Class
subclass of: coil
disjoint with: one-channel-coil
definition: A MULTI-CHANNEL COIL consists of an array of mutually decoupled, geometrically optimized surface coils, which receive MR signal simultaneously.

multi-echo-gradient-echo-sequence
type: Class
subclass of: gradient-echo-sequence
definition: A MULTI-ECHO GRADIENT-ECHO SEQUENCE uses a series of echoes acquired as a train following after a single excitation pulse. Multiple symmetrical or asymmetrical echoes can be acquired. In multi-echo imaging, either this train of echoes is used to produce multiple images (one per echoe, for T2 measurement for instance) or to accelerate single image acquisition (for instance EPI).

multi-echo-spin-echo-sequence
type: Class
subclass of: spin-echo-sequence
definition: A MULTI-ECHO SPIN-ECHO SEQUENCE uses a series of echoes acquired as a train following after a single excitation pulse. Multiple symmetrical or asymmetrical echoes can be acquired. In multi-echo imaging, either this train of echoes is used to produce multiple images (one per echo, for T2 measurement for instance) or to accelerate single image acquisition (for instance TSE, RARE) or to accelerate multi-slices acquisitions (FSE).

non-conventional-MR-sequence
type: Class
subclass of: MR-sequence
definition: A NON-CONVENTIONAL MR SEQUENCE is a MR SEQUENCE involving “multiple refocusing pulses to acquire several lines of k space in a single TR period” [Boyle et al., 2006].

non-conventional-cartesian-MR-sequence
type: Class
subclass of: non-conventional-MR-sequence
disjoint with: non-conventional-non-cartesian-MR-sequence
definition: A NON-CONVENTIONAL CARTESIAN MR SEQUENCE is a NON-CONVENTIONAL MR SEQUENCE in which “the geometry of k-space traversal is rectilinear.” [DICOM Standard, 2008]

non-conventional-non-cartesian-MR-sequence
type: Class
subclass of: non-conventional-MR-sequence
definition: A NON-CONVENTIONAL NON-CARTESIAN MR SEQUENCE is a NON-CONVENTIONAL MR SEQUENCE in which “the geometry of k-space traversal is not rectilinear, e.g. radial or spiral.” [DICOM Standard, 2008]

non-interlaced-slice-order
type: Class
subclass of: slice-order
subclass of: Restriction
  on property: has-for-name
  has value: non-interlaced
definition: Slices are acquired in a sequential order.

non-parallel-RF-signal-acquisition
type: Class
subclass of: radio-frequency-signal-acquisition
subclass of: Restriction
  on property: has-for-instrument-at
  some values from: one-channel-coil
subclass of: Restriction
  on property: has-for-name
  has value: non-parallel
definition: Only one channel is available for signal acquisition

nucleus
type: Class
subclass of: physical-object
subclass of: Restriction
  on property: has-for-name
  some values from: name
definition: A nucleus is the central part of an atom, composed of neutrons and protons.

number-of-averages
type: Class
subclass of: cardinal
definition: The NUMBER OF AVERAGES is the “number of times a given pulse sequence is repeated before any parameter is changed” [DICOM Standard, Part 3].

number-of-averages-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: number-of-averages
  qualified cardinality: 1

number-of-phase-encoding-steps
type: Class
subclass of: cardinal
definition: THE NUMBER OF PHASE ENCODING STEPS is the “total number of lines in k-space in the 'y' direction collected during acquisition” [DICOM Standard, Part 3].

number-of-phase-encoding-steps-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: number-of-phase-encoding-steps
  qualified cardinality: 1

number-of-temporal-positions
type: Class
subclass of: cardinal
definition: Total number of temporal positions.

number-of-temporal-positions-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: number-of-temporal-positions
  qualified cardinality: 1

oblique-slice-orientation-at-acquisition
type: Class
subclass of: slice-orientation-at-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: oblique
definition: The directions of rows and columns are not aligned with the 3 cardinal directions (Antero-Posterior, Head-Foot, Right-Left).

one-channel-coil
type: Class
subclass of: coil
definition: A ONE-CHANNEL COIL is used to receive MR signal.

parallel-RF-signal-acquisition
type: Class
subclass of: radio-frequency-signal-acquisition
subclass of: Restriction
  on property: has-for-instrument-at
  some values from: multi-channel-coil
subclass of: Restriction
  on property: has-for-name
  has value: parallel
definition: Parallel imaging exploits the multiple elements of a phased array coil.

parallel-acquisition-technique
type: Class
subclass of: protocol
subclass of: Restriction
  on property: has-for-quality
  some values from: time-reduction-factor
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
definition: [DIV] Names of parallel acquisition techniques are in many cases given by manufacturers. For instance, ‘GRAPPA’ and ‘mSENSE’ are two names of techniques given by Siemens.

parallel-versus-non-parallel-acquisition-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: radio-frequency-signal-acquisition
  qualified cardinality: 1

patient-position
type: Class
subclass of: state
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
subclass of: Restriction
  on property: is-borne-by-at
  some values from: subject
definition: A PATIENT POSITION “specifies the position of the patient relative to the imaging equipment space. This attribute is intended for annotation purposes only. It does not provide an exact mathematical relationship of the patient to the imaging equipment. When facing the front of the imaging equipment, Head First is defined as the patient’s head being positioned toward the front of the imaging equipment. Feet First is defined as the patient’s feet being positioned toward the front of the imaging equipment. Prone is defined as the patient’s face being positioned in a downward (gravity) direction. Supine is defined as the patient’s face being in an upward direction. Decubitus Right is defined as the patient’s right side being in a downward direction. Decubitus Left is defined as the patient’s left side being in a downward direction” [DICOM Standard, Part 3].

patient-position-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: patient-position
  qualified cardinality: 1

percent-phase-field-of-view
type: Class
subclass of: abstract-quality
definition: The PERCENT PHASE FIELD OF VIEW is the “Ratio of field of view dimension in phase direction to field of view dimension in frequency direction, expressed as a percent” [DICOM Standard, Part 3].

percent-phase-field-of-view-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: percent-phase-field-of-view
  qualified cardinality: 1

percent-sampling
type: Class
subclass of: abstract-quality
definition: The PERCENT SAMPLING is the “fraction of acquisition matrix lines acquired, expressed as a percent” [DICOM Standard, Part 3].

percent-sampling-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: percent-sampling
  qualified cardinality: 1

performed-acquisition-MR-protocol
type: Class
subclass of: MR-protocol
subclass of: Restriction
  on property: has-for-constant-part
  on class: MR-sequence
  qualified cardinality: 1
subclass of: Restriction
  on property: refers-to
  on class: MR-dataset-acquisition
  qualified cardinality: 1
subclass of: Restriction
  on property: refers-to
  on class: subject
  qualified cardinality: 1
disjoint with: planned-acquisition-MR-protocol
definition: A PERFORMED ACQUISITION MR PROTOCOL is a MR PROTOCOL which specifies details and acquisition protocol parameters values as performed during a specific MR DATASET ACQUISITION.

perfusion-sequence
type: Class
subclass of: MR-sequence
definition: Perfusion imaging allows to explore mircrovascularisation. Several techniques are available using contrast agents, superparamagnetic contrast agents or arterial spin labelling. Example: TGSE (Turbo-Gradient-Spin-Echo) SEQUENCES are examples of PERFUSION SEQUENCES.

pixel-bandwidth
type: Class
subclass of: temporal-quality
definition: The PIXEL BANDWIDTH is the “reciprocal of the total sampling period, in hertz per pixel” [DICOM Standard, Part 3].

pixel-bandwidth-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: pixel-bandwidth
  qualified cardinality: 1

pixel-spacing-in-x
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: dataset
  qualified cardinality: 1
definition: The PIXEL SPACING IN X is the “physical distance in the patient between the center of each pixel specified by the adjacent row spacing in mm” [DICOM Standard, Part 3].

pixel-spacing-in-x-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: pixel-spacing-in-x
  qualified cardinality: 1

pixel-spacing-in-y
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: dataset
  qualified cardinality: 1
definition: The PIXEL SPACING IN Y is the “physical distance in the patient between the center of each pixel specified by the adjacent column spacing in mm” [DICOM Standard, Part 3].

pixel-spacing-in-y-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: pixel-spacing-in-y
  qualified cardinality: 1

planned-acquisition-MR-protocol
type: Class
subclass of: MR-protocol
definition: A PLANNED ACQUISITION MR PROTOCOL is a MR PROTOCOL which specifies details and acquisition protocol parameters. It provides guidance to the modality on how an acquisition should be performed, such as desired values or values ranges for certain parameters, patient handling instructions for the operator, etc.

radio-frequency-signal-acquisition
type: Class
subclass of: conceptual-action
subclass of: Restriction
  on property: is-a-part-of
  on class: MR-dataset-acquisition
  qualified cardinality: 1
subclass of: Restriction
  on property: has-for-instrument-at
  some values from: receiving-coil
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
subclass of: Restriction
  on property: has-for-instrument-at
  some values from: transmitting-coil
definition: The coil for emitting or receiving the radio-frequency signal can be designed with multi-channel for a parallel signal acquisition

receiving-coil
type: Class
subclass of: coil
subclass of: Restriction
  on property: has-for-role-name
  has value: receiving
definition: A RECEIVING COIL is a coil used to receive the NMR signal emitted by the excited atoms returning to their steady state.

refocused-gradient-echo-sequence
type: Class
subclass of: single-echo-gradient-echo-sequence
definition: Refocused GRE sequences use a refocusing gradient in the phase encoding direction to maximize (refocus) remaining xy-magnetization at the time when the next excitation is due, while the other two gradients are, in any case, balanced. In refocused gradient-echo sequences, the NMR signal comes not only from the nuclei within the slice, but also from spins that are downstream and outside the slice but still inside the receiver coil.

repetition-time
type: Class
subclass of: temporal-quality
definition: The REPETITION TIME is “the period time in msec between the beginning of a pulse sequence and the beginning of the succeeding (essentially identical) pulse sequence” [DICOM Standard, Part 3].

repetition-time-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: repetition-time
  qualified cardinality: 1

sagittal-slice-orientation-at-acquisition
type: Class
subclass of: slice-orientation-at-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: sagittal
definition: if (Row= Head-Foot and Column= Antero-Posterior) or (Row= Antero-Posterior and Column= Head-Foot).

segmented-gradient-echo-echo-planar-imaging-sequence
type: Class
subclass of: multi-echo-gradient-echo-sequence
definition: With interleaved EPI or segmented EPI the k-space is covered in two or more segments. The acquisition of all the data points required to make up the image in several FIDs. For instance, for a two shot interleaved EPI sequence, the first interleave covers the whole of k-space in alternate lines, and then the second pass fills in the lines between. The same principle holds for any number of interleaves. There are other ways that k-space can be segmented, for example, acquiring the positive ky values in the first shot, and negative values in the second. It seems appropriate to refer to the kind of technique as interleaved EPI, since the two shots are indeed interleaved on reconstruction, and to refer to other multi-shot techniques as segmented EPI.

segmented-spin-echo-sequence
type: Class
subclass of: multi-echo-spin-echo-sequence
definition: A SEGMENTED SPIN-ECHO SEQUENCE “uses multiple spin echoes with different phase-encoding steps in order to fill the k-space. » [Nitz et al., 1999]. Segmented spin-echo pulses increase fMRI signal.

single-echo-gradient-echo-sequence
type: Class
subclass of: gradient-echo-sequence
definition: A SINGLE-ECHO GRADIENT-ECHO SEQUENCE requires the successive application of as many excitation pulses as there are k-space lines to fill.

single-echo-spin-echo-sequence
type: Class
subclass of: spin-echo-sequence
definition: A SINGLE-ECHO SPIN-ECHO SEQUENCE requires the successive application of as many 180° pulses as there are k-space lines to fill.

single-shot-gradient-echo-echo-planar-imaging-sequence
type: Class
subclass of: multi-echo-gradient-echo-sequence
definition: Echo planar sequences are rapid sequences essential basis for advanced MRI applications such as diffusion, perfusion and functional imagery based on blood oxygen level dependent (BOLD) effect.

single-shot-spin-echo-sequence
type: Class
subclass of: multi-echo-spin-echo-sequence
definition: A SINGLE-SHOT SPIN-ECHO SEQUENCE uses “one excitation and multiple echoes to fill half of the k-space”. [Nitz et al., 1999]

slice-order
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: dataset
  qualified cardinality: 1
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
definition: Define the acquisition slice order. It can be non-interlaced or interlaced, odd or even.

slice-order-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: slice-order
  qualified cardinality: 1

slice-orientation-at-acquisition
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: has-for-name
  on class: name
  qualified cardinality: 1
subclass of: Restriction
  on property: is-a-quality-of
  on class: dataset
  qualified cardinality: 1
definition: For Three-dimensional object the slices can be acquired in 4 directions: sagittal, coronal, transverse or oblique.

slice-orientation-at-acquisition-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: slice-orientation-at-acquisition
  qualified cardinality: 1

slice-spacing
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: dataset
  qualified cardinality: 1
definition: THE SLICE SPACING is the “spacing between slices, in mm. The spacing is measured from the center-to-center of each slice” [DICOM Standard, Part 3].

slice-spacing-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: slice-spacing
  qualified cardinality: 1

slice-thickness
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: dataset
  qualified cardinality: 1
definition: The SLICE THICKNESS is the “nominal reconstructed slice thickness, in mm” [DICOM Standard, Part 3].

slice-thickness-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: slice-thickness
  qualified cardinality: 1

spectroscopy-sequence
type: Class
subclass of: MR-sequence
definition: Magnetic resonance spectroscopy allows non invasive and in vivo exploration of the molecular composition of tissue. It identifies certain molecular constituents - the metabolites - involved in physiological or pathological processes. MR spectroscopy can be performed on different nuclei.

spin-density-contrast
type: Class
subclass of: MR-image-contrast
subclass of: Restriction
  on property: has-for-name
  has value: spin-density
definition: A SPIN DENSITY CONTRAST is a MR IMAGE CONTRAST which is predominantly caused by differences in the spin density, of the tissues.

spin-echo-echo-planar-imaging-sequence
type: Class
subclass of: multi-echo-spin-echo-sequence
definition: Rapid technique, EPI collects an MR image, from a single free induction decay signal (FID), in about 40 to 100 ms idela to follow brain dynamic phenomenon. Examples: SE-EPI (Spin Echo - Echo Planar Imaging) and EPI-SE (Echo Planar Imaging - Spin Echo) are examples of SPIN ECHO-ECHO PLANAR IMAGING SEQUENCES. We treat them as names for such SEQUENCES.

spin-echo-sequence
type: Class
subclass of: MR-sequence
definition: A SPIN-ECHO SEQUENCE is composed of “a 90° excitation pulse followed by a delay of TE/2 and the application of a 180° refocusing pulse. The refocusing pulse rephases transverse components of magnetization to form an echo at time TE. T1, T2, and proton-density weighting can be obtained based on an appropriate choice of TE and TR. Spin-echo imaging shows sensitivity to T2 rather than to T2*, making it less sensitive to magnetic susceptibility artifacts.” [Boyle et al., 2006]

spoiled-gradient-echo-sequence
type: Class
subclass of: single-echo-gradient-echo-sequence
definition: “Spoiled gradient-echo sequences destroy or "spoil" any residual transverse magnetization remaining at the end of each TR. In that way, every RF flip applied in a sequence acts solely on longitudinal magnetization. The sequence is used in fast T1-weighted imaging. The short TRs allow 3D and breath-hold 2D acquisitions.” [Boyle et al., 2006] Examples: FLASH (fast low-angle shot), is an example of SPOILED GRADIENT-ECHO SEQUENCE provided by Siemens Medical Solutions. T1-FFE (T1-weighted fast field echo) is an example of SPOILED GRADIENT-ECHO SEQUENCE provided by Philips Medical Systems. SPGR (spoiled gradient echo) is an example of SPOILED GRADIENT-ECHO SEQUENCE provided by GE Medical Systems.

standard-segmented-gradient-echo-echo-planar-imaging-sequence
type: Class
subclass of: segmented-gradient-echo-echo-planar-imaging-sequence
definition: It uses no magnetization preparation.

standard-segmented-spin-echo-sequence
type: Class
subclass of: segmented-spin-echo-sequence
definition: A STANDARD SEGMENTED SPIN-ECHO SEQUENCE uses no magnetization preparation. Examples: FSE (Fast Spin Echo) is an example of STANDARD SEGMENTED SPIN-ECHO SEQUENCE proposed by GE. TSE (Turbo Spin Echo) is an example of STANDARD SEGMENTED SPIN-ECHO SEQUENCE proposed by Philips. We treat them as names for such SEQUENCES.

standard-single-echo-spin-echo-sequence
type: Class
subclass of: single-echo-spin-echo-sequence
definition: A STANDARD SINGLE-ECHO SPIN-ECHO SEQUENCE involves no preparation of the longitudinal magnetization. Examples: CSE (conventional spin echo) and SE (spin echo) are examples of STANDARD SINGLE-ECHO SPIN-ECHO SEQUENCES. We treat them as names for such SEQUENCES.

standard-single-shot-gradient-echo-echo-planar-imaging-sequence
type: Class
subclass of: single-shot-gradient-echo-echo-planar-imaging-sequence
definition: uses no magnetization preparation. Largely used for functional MRI (GRE EPI)

standard-single-shot-spin-echo-sequence
type: Class
subclass of: single-shot-spin-echo-sequence
definition: A STANDARD SINGLE-SHOT SPIN-ECHO SEQUENCE uses no magnetization preparation. Examples: SS FSE (Single Shot Fast Spin EchoFast), HASTE (Half-Fourier Acquisition Single-Shot Turbo Spin-Echo), and RARE (Rapid Acquisition with Rapid Enhancement) are examples of STANDARD SINGLE-SHOT SPIN-ECHO SEQUENCES. We treat them as names for such SEQUENCES.

steady-state-gradient-echo-FID-sequence
type: Class
subclass of: refocused-gradient-echo-sequence
definition: “SS GRE FID sequences (SSFP-FID) are a type of gradient-echo sequence in which the transverse component is not spoiled. In a SS GRE FID sequence an echo of the FID signal component is sampled… Used for its T1/T2* contrast at short TR values. A long TR produces similar contrast to that of a spoiled gradient-echo sequence. Signal-to-noise ratio is better than that of a spoiled gradient-echo (FLASH) sequence, since the SS GRE FID sequence "recycles" the transverse component that is destroyed in a spoiled gradient-echo sequence. The short TRs means SS GRE FID sequences are suitable for 3D and sequential 2D imaging, but not for interleaved 2D imaging.” [Boyle et al., 2006] Examples: FISP (fast imaging with steady-state precession) is an example of STEADY STATE GRADIENT-ECHO FID SEQUENCE provided by Siemens Medical Solutions. FFE (fast field echo) is an example of STEADY STATE GRADIENT-ECHO FID SEQUENCE provided by Philips Medical Systems. GRASS (gradient-recalled acquisition in the steady state) is an example of STEADY STATE GRADIENT-ECHO FID SEQUENCE provided by GE Medical Systems.

steady-state-gradient-echo-FID-stimulated-echoes-sequence
type: Class
subclass of: steady-state-gradient-echo-FID-sequence
subclass of: steady-state-gradient-echo-stimulated-echoes-sequence
definition: Article ‘Steady-state free precession imaging’ of Wikipedia: “... If, within one TR, either one of the gradient moments of magnetic gradients along three logical directions, including slice selection direction (G_ss), phase encoding (G_pe) and readout (G_ro), is not zero, then spins along such direction obtain different phases making the signal intensity (SI) of a single voxelis a vector sum of magnetizations therein. It cause some inevitable loss of SI. Such situations belong to ordinary SSFP imaging,. Otherwise, if all gradient moments are zero within one TR, i.e. gradients of opposite polarities cancel out, then there are no additional effects on the phase from gradients; that is to say, SI of each voxel is the contributions of a series of RF pulses and relaxation phenomena.” Examples: DESS (Double-Echo Steady State) is an example of STEADY STATE GRADIENT-ECHO FID + STIMULATED ECHOES SEQUENCE provided by Siemens Medical Solutions. SSFP (Steady State Free Precession). FIESTA (Fast Imaging Employing STeady-state Acquisition) CISS (Constructive Interference in the Steady State) is an example of STEADY STATE GRADIENT-ECHO FID + STIMULATED ECHOES SEQUENCE provided by Siemens Medical Solutions. True FISP (True Fast Imaging in a Steady State Precession) is an example of STEADY STATE GRADIENT-ECHO FID + STIMULATED ECHOES SEQUENCE provided by Siemens Medical Solutions.

steady-state-gradient-echo-stimulated-echoes-sequence
type: Class
subclass of: refocused-gradient-echo-sequence
definition: Article ‘Steady-state free precession imaging’ of Wikipedia: “Steady-state free precession (SSFP) imaging is a MRI technique which uses steady states of magnetization. In general, SSFP MRI sequences are based on a (low flip angle) gradient-echo MRI sequence with a short repetition time which in its generic form has been described as the flash MRI technique. While spoiled gradient-echo sequences refer to a steady state of the longitudinal magnetization only, SSFP gradient-echo sequences include transverse coherences (magnetizations) from overlapping multi-order spin echoes and stimulated echoes. This is usually accomplished by refocusing the phase-encoding gradient in each repetition interval in order to keep the phase integral (or gradient moment) constant. Fully balanced SSFP MRI sequences achieve a phase of zero by refocusing all imaging gradients.” Examples: PSIF (a backward-running FISP) is an example of STEADY STATE GRADIENT-ECHO – STIMULATED ECHOES SEQUENCE provided by Siemens Medical Solutions. SSFP (Steady state free precession) is an example of STEADY STATE GRADIENT-ECHO – STIMULATED ECHOES SEQUENCE provided by GE Medical Systems. CE-FAST (Contrast-enhanced FAST) is an example of STEADY STATE GRADIENT-ECHO – STIMULATED ECHOES SEQUENCE provided by Picker international. CE FFE-T2 (Contrast Enhanced Fast Field Echo (T2-weighted))

surface-coil
type: Class
subclass of: coil
subclass of: Restriction
  on property: has-for-type-name
  has value: surface
definition: A SURFACE COIL is a coil restricted to a part of a volumic object.

temporal-resolution
type: Class
subclass of: temporal-quality
definition: The TEMPORAL RESOLUTION is the “time delta between images in a dynamic or functional set of images” [DICOM Standard, Part 3].

temporal-resolution-value-information
type: Class
subclass of: information
subclass of: Restriction
  on property: refers-to
  on class: temporal-resolution
  qualified cardinality: 1

time-of-flight-angio-sequence
type: Class
subclass of: angiography-sequence
definition: The time of flight angiography is used for the imaging of vessels. Usually the sequence type is a gradient echo sequence with short TR, acquired with slices perpendicular to the direction of blood flow. Examples: TOF GRE (Time of flight Gradient Echo) SEQUENCES are examples of TIME OF FLIGHT ANGIO SEQUENCES. TOF SPGR (Time of flight SPoiled Gradient-Recalled acquisition in the steady state) SEQUENCES are examples of TIME OF FLIGHT ANGIO SEQUENCES.

time-reduction-factor
type: Class
subclass of: abstract-quality
subclass of: Restriction
  on property: is-a-quality-of
  on class: parallel-acquisition-technique
  qualified cardinality: 1

transmitting-coil
type: Class
subclass of: coil
subclass of: Restriction
  on property: has-for-role-name
  has value: transmitting
definition: A TRANSMITTING COIL is a coil used to create the RF signal that pertubates the initial alignment to the B0 direction of the imaged atoms.

transverse-slice-orientation-at-acquisition
type: Class
subclass of: slice-orientation-at-acquisition
subclass of: Restriction
  on property: has-for-name
  has value: transverse
definition: if (Row= Antero-Posterior and Column= Right-Left) or (Row= Right-Left and Column= Antero-Posterior).

velocity-encoded-angio-sequence
type: Class
subclass of: angiography-sequence
definition: VELOCITY ENCODED ANGIO SEQUENCES are sequences sensitive to the velocity of spins. Phase contrast angiography (PCA) relies on dephasing the moving spins submitted to a bipolar gradient. For a bipolar gradient of a given intensity and time, the moving spins will dephase in proportion to their velocity. The encoding gradient characteristics are thus defined in order to encode flows within a certain velocity range from – venc to + venc to be determined by the user. Any velocity outside this range will be poorly encoded. In 2D, for the quantitative study of flows, the slice plane must be perpendicular to flow direction. Thus a flow velocity curve can be obtained as a function of time, which, when coupled with morphologic data (vascular section) will calculate the flow rate. In phase contrast volumetric acquisition, each partition is encoded in 3 directions. To reduce acquisition time, the number of phase encoding steps must be reduced. The images are then reconstructed in maximum intensity projection (MIP). Examples: 2D PCA (Bi-dimensional Phase Contrast Angiography) SEQUENCES are examples of VELOCITY ENCODED ANGIO SEQUENCES. 3D PCA (Three-dimensional Phase Contrast Angiography) SEQUENCES are examples of VELOCITY ENCODED ANGIO SEQUENCES. VENC (Velocity-ENcoded Cine) SEQUENCES are examples of VELOCITY ENCODED ANGIO SEQUENCES.