MRI Glossary of Terms(MRI术语表)

mri

General MRI:

• Image description图像描述— include industry standard sequence name (e.g., FAST, MP-RAGE, SPGR)
• Scanner Vendor 供应商 — name of company that manufactures the scanner console (e.g., GE)
• Scanner Model产品名称— model name for scanner (e.g., Siemens Allegra)
• Scanner Operating System  操作系统— version designation of the scanner operating system (e.g., Siemens vb13).
• Field Strength场强— strength of the main magnetic field in Tesla
• Maximum gradient amplitude最大梯度强度— maximum amplitude of field gradient insert in mT/m
• (Maximum) Slew Rate切换率— maximum rate of change of the gradient amplifier output for any input signal
• Coil Type线圈类型— description of scanning coil used (e.g., 12 channel head coil)
• Acceleration factor加速因子-the factor by which the distance between separate lines in k-space have been increased (used for parallel imaging only)
• TR (repetition time) 重复时间— The duration of time in ms between the first pulse in one application of a pulse sequence and the first pulse in the subsequent application.
• TE (echo time) 回波时间— The duration of time in ms between the center of the initial RF pulse in a pulse sequence and the center of the signal echo formed by that pulse sequence.
• Flip Angle 翻转角度— the angle by which the net magnetization vector is rotated away from that of the main magnetic field during the application of an RF pulse. Usually only specified for gradient echo sequences.
• Number of slices 层数— the number of individual images obtained from a pulse sequence. Each image is centered at a separate point in space.
• Slice Thickness 层厚— The thickness of the volume in mm from which signal is acquired to form each image.
• Field of View 视野— the in-plane image dimension(s) in mm.
• Bandwidth 带宽— the range of frequencies sampled by the MRI receiver analog-to-digital converter. Usually specified as ± ###### Hz.
• Matrix size 矩阵大小— for a multi-slice 2D image, the matrix (i,j,k) where i is the number of phase encoding steps, j is the number of data points acquired during the acquisition time, and k is the number of slices. More generally defined as the dimensions of the matrix into which the imaging data is stored after Fourier transform of the raw data.
• Image Orientation 图像方向— direction in which the slice position of the imaging volume is varied. Choices are axial (transverse), coronal, sagittal, oblique. If oblique, more information is required.
• Data file format 数据文件格式— The format of the files used to store the imaging data. Examples include DICOM, NIFTI, ANALYZE, and NRRD.
  

Functional MRI Data

• K-space traversal (spiral, linear, other)K空间？—the pattern followed in k-space during acquisition time.
  

• Number of Time Points or volumes — number of individual image volumes acquired during an fMRI experiment.
  

• Number of Dummy Acquisitions — the number of scans that are initiated before the actual data are collected in order to begin acquisition with magnetization in a steady-state. Care must be taken to distinguish actual dummy scans and scans that are acquired and stored but then discarded before analysis of the data.
  

• Slice Gap — the distance in mm left between the nearest imaging slices.
  

• Slice order (interleaved/sequential, L/R, A/P, S/I, etc.) — the order in which slices are stored. Examples are 1. 3. 5. 7. 2. 4. 6. 8 (interleaved) and 1, 2, 3, 4, 5, 6, 7, 8 (sequential)
  

• Phase direction — the direction in magnet coordinates along which the phase-coding gradient varies.
  

Diffusion Tensor Imaging Data
(The first grouping is from the Nearly Raw Raster Data (NRRD) standard discussed at [url=http://wiki.na-mic.org/Wiki/index.php/NAMIC_WikiTI:Nrrd_format)--this]http://wiki.na-mic.org/Wiki/index.php/ NAMIC_WikiTI:Nrrd_format)--this[/url] is basically XCEDE for DTI, as far as I can tell??

• Kinds - The "kinds" field identifies which of the four axes is for storing the DWI image values, as opposed to the 3 spatial image domain axes. The single non-spatial axis is identified by either "list" or "vector" (the latter being allowed to be compatible with how ITK writes out non-scalar NRRDs by default).
  
  • The location of the non-spatial axis among the spatial axes determines the interleaving of the pixel data (which values you see when as you traverse through all the image values in memory address order) For example:
  • "kinds: space space space list": volume interleaved: first you go through all the slices for one gradient direction, and then you go through the slices for a second gradient direction.
  • "kinds: space space list space": slice interleaved: for one 2-D slice location you go through the DWI values, before you move on to the next physical slice.
  • "kinds: list space space space": pixel interleaved: you go through the DWI values for each pixel before moving on to the values for the next pixel.
    

Data type 数据类型— A name designating the length of the data unit. (Example: short for 16-bit data) Endian 字节序— the ordering of the data’s bytes. (Example: little) Byte skip — are there any bytes skipped at the beginning of the data? (-1 = no, # = the number of bytes skipped. Space — the coordinate system defining the patient reference frame (Example: right-anterior-superior Space directions — The columns of the matrix used to convert the diffusion-weighted directions from the magnet space to pixel coordinate space. (Example: (-0.9375,0,0) (0,-0.9375,0) (0,0,-3) none; i.e.,

• Space units — The units that are used to define the space covered by the data. (Example: "mm" "mm" "mm")
• Space origin — the coordinate origin of the center of the data. (Example: 125.00,124.10,79.3)
• Measurement frame - This is the transformation matrix for the magnet frame (x,y,z) to the image to the subject space (named in the “space” tag above. (Example: (0,-1,0) (1,0,0) (0,0,-1) )
• Name of diffusion-weighted directions set (i.e., Jones30, Siemens default 30, …) — common or vendor name and number of diffusion-weighted directions.
• Diffusion-weighted directions (list) — the list of direction vectors; usually normalized to one.
• Number of b=0 volumes — number of imaging volumes acquired without any diffusion-weighting gradients applied.
• b=0 volumes first? — Are the b=0 volumes acquired first before the of b ¹ 0 volumes? (this might not be needed — can be determined from the list of diffusion-weighted directions).
• Number of b ¹ 0 volumes — total number of diffusion-weighted directions for which an imaging volume is acquired.
• Total number of b-values / volumes = the sum of the previous two numbers (this is only here for easier searching)
• Multiple b ¹ 0 values? (y,n) — Is more than one diffusion-weighting gradient amplitude applied?
• b value(s) — the list of diffusion-weighting gradient amplitude(s)
  

medstd

mri 发表于 2015-11-15 22:33
General MRI:

Image description图像描述— include industry standard sequence name (e.g., FAST, M ...

核磁图片很漂亮，术语也很实用
来自: 微社区

mri

mri 发表于 2015-11-15 22:33
General MRI:

Image description图像描述— include industry standard sequence name (e.g., FAST, M ...

以前收集的，希望对大家有帮助☺
来自: 微社区

13636600535

看看高人有多高

devstd

好文章，值得学习，顶起来

ultrasound

好贴！

oevko

这个东西一定要看看