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In 2075 (after about 100 years of ...) the MRI scan will be :
obsolete 
done with handheld probe 
done at home (app, ...) 
a 3 second walk through 
daily done 
replaced by something much ... 



 
MRI Coils
• Surface Coils •
  • Surface Coils
  
ball_redSurface Coil 
A surface coil is essentially a loop of conducting material, such as copper tubing. The in-bore solenoidal sending coil is used as the transmitter of RF energy. This type of receiver coil is placed directly on or over the region of interest for increased magnetic sensitivity. The loop may form various shapes and be bent slightly to conform to the imaged body part. Surface coils have a good SNR for tissues adjacent to the coil and because the signal decrease with the distance, an eligibility homogeneity correction will equalize this over the field of view. A rule of thumb for surface coils is that the sensitivity decreases appreciably beyond a distance equal to the diameter of the coil.
The positioning of the coil is an important determinant of performance. As only the region close to the surface coil will contribute to the signal, there is an improvement in the SNR for these regions, compared to the use of receiver coils that surround the appropriate part of the body. These coils are specifically designed for localized body regions, and provide improved signal to noise ratios by limiting the spatial extent of the excitation or reception.

See also the related poll result: '3rd party coils are better than the original manufacturer coils'

• View the DATABASE results for 'Surface Coil' (81).Open this link in a new window

 
Array Coil 
An array coil combines the advantages of smaller coils (high SNR) with those of larger coils (large measurement field). This type of RF coil is composed of separate multiple smaller coils, which can be used individually (switchable coil) or combined.
When used simultaneously, the elements can either be:
coupled array coils - electrically coupled to each other through common transmission lines or mutual inductance
isolated array coils - electrically isolated from each other with separate transmission lines and receivers and minimum effective mutual inductance, and with the signals from each transmission line processed independently or at different frequencies
phased array coils - multiple small coils arranged to efficiently cover a specific anatomic region and obtain high-resolution, high-SNR images of a larger volume. The data from the individual coils is integrated by special software to produce the high-resolution images.

See also the related poll result: '3rd party coils are better than the original manufacturer coils'
 
Images, Movies, Sliders:
 Anatomic Imaging of the Lumbar Spine  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 

• View the NEWS results for 'Array Coil' (1).Open this link in a new window.

• View the DATABASE results for 'Array Coil' (22).Open this link in a new window

 
Further Reading:
MR-TIP Forum - Related Threads 
• 'Open MRI'
• 'custom all types of coils'
• 'coil configuration'
• 'Philips Pin Config - 4 channel'
• 'Experiences with Artroscan C'

Body Wrap Around Coil 
(BWA) A flexible surface coil for body imaging.
 
Images, Movies, Sliders:
 Anatomic Imaging of the Liver  Open this link in a new window
      

 
Linearly Polarized Coil 
(LP Coil) A coil designed to excite or detect spins using one RF transmit and/or receive channel. The magnetic field has predominantly a single direction.

• View the DATABASE results for 'Linearly Polarized Coil' (2).Open this link in a new window

Phased Array Coil 
The phased array coils operate typically as receive only coils. In that case, the in the MRI device implemented body coil act as the transmitter and sends the radio frequency energy to generate the excitation pulses. State-of-the-art array coil systems include the use of 4 (up to 32) coils with separate receivers. This method is often referred to as a phased array system, although the signals are not added such that the signal phase information is included. The use of phased array coils allows the decreasing of the number of signal averages, which shortens the scan time by high SNR and resolution.
High-sensitivity RF surface coils and digital processing algorithms have been developed that speed up image acquisition and reconstruction during the MRI scan.
Fast parallel imaging techniques, for example sensitivity encoding (SENSE), 'Partially Parallel Imaging with Localized Sensitivity' (PILS), Simultaneous Acquisition of Spatial Harmonics (SMASH) or Array Spatial Sensitivity Encoding Technique (ASSET) use phased array multichannel coils to further improve spatial and temporal resolution. The sensitivity profile of a phased array coil element is measured by a separate low resolution 3D acquisition over the entire field of view in the case of a SENSE acquisition. For an mSENSE measurement, a self-calibration acquires some of the missing lines in the center of the k-space.
Also called linear array coil or synergy surface coil.

See also the related poll result: '3rd party coils are better than the original manufacturer coils'

• View the DATABASE results for 'Phased Array Coil' (9).Open this link in a new window

 
Saddle Coil 
A saddle coil has a cylindrical body, with one or more turns of wire (older versions) or foil (newer versions) on each side. It generates a very homogenous field in the direction of its long axis. To achieve a higher B1 homogeneity there are different developments like Folded Litz-foil Saddle Coils or Etched Litz-foil Saddle Coils.

See also the related poll result: '3rd party coils are better than the original manufacturer coils'

• View the DATABASE results for 'Saddle Coil' (6).Open this link in a new window

 
Surface Coil NMR 
A surface coil placed over a region of interest will have an effective selectivity for a volume approximately subtended by the coil circumference and one radius deep from the coil center. Such a coil can be used for simple localization of sites for measurement of chemical shift spectra, especially of phosphorus, and blood flow studies. Some additional spatial selectivity can be achieved with magnetic field gradients.
MRI Knowledge Resources from Universities, Companies, Agencies, etc. 
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