- Object ID: 00000018WIA30902970GYZ
- Topic ID: id_40024839 Version: 1.3
- Date: Aug 18, 2022 2:23:01 PM
IDEAL: display images
About this task
Use these steps to display images acquired with the IDEAL Imaging Option.
Step-by-step instructions
- From the Patient List, select the series with the IDEAL images.
- See Imaging Options annotation for series annotation details.
- Select the desired series and from the Session application list, click Viewer.
- The annotated NEX is different from the NEX value entered for the scan prescription. The annotated NEX reflects the value needed to optimize image quality and it is typically three times the NEX value entered.
- The water-only and fat-only images are annotated as W/F, respectively. The effective TE is annotated as effective TE of the unshifted spin echo for 2D FSE and FRFSE, and as the average of the three TEs for 3D FSPGR and FGRE with IDEAL.
- The water+fat (in-phase) and water-fat (out-of-phase) images are annotated as OutPh or InPh, respectively. The effective TE is annotated as the corresponding fat/water in- or out-phase TE, bracketed by the three shifted echo times in the case of 3D FGRE and FSPGR with IDEAL, and as the unshifted spin echo's effective TE for 2D FSE and FRFSE with IDEAL.
- IDEAL acquisition is a 3-NEX-equivalent scan. All water, fat, in-phase and out-phase images generated with IDEAL are annotated as 3 NEX.
- The success of spectral saturation techniques depends on the uniformity of the anatomical area being imaged, in addition to the pulse sequence and coil being used. While the system is shimmed to a system specification to provide you with optimal homogeneity, once a patient is placed in the magnet bore, the homogeneity can be affected. For example, an abdomen may be more uniform than a shoulder. It works best with anatomy of interest at isocenter, a small FOV, and no patient motion. In spite of careful patient positioning, all images within the IDEAL acquisition may not have complete fat or water suppression due to patient inhomogeneities such as areas in and around air cavities and metal implants, etc.
- The water image will have about 10 to 20% fat signal because the pulse sequence and processing used is more like the Classic fat saturation technique rather than the fat saturation technique.
CAUTION Images labeled as water may include signal from fatty tissue, and images labeled as fat may include signal from water. This error may occur in regions of high magnetic field variation, in spatially isolated tissue, due to patient or tissue motion, due to phase wrap artifacts, and/or in images with low signal-to-noise ratios. The presence of fat tissue in images labeled as water, or vice versa, may occur within single images or throughout an in entire stack of slices. By default, both sets of images (labeled fat and labeled water) will be reconstructed and inserted into the database for review. Proper calibration and center frequency selection will reduce the occurrence of this error. Complete elimination of this error may not be possible and thus interpretation of MR images must be completed by trained personnel.