• Object ID: 00000018WIA30088970GYZ
  • Topic ID: id_40026438 Version: 1.4
  • Date: May 23, 2022 2:26:05 AM

MR-Touch

READY View MR-Touch is a post process of an MR-Touch acquisition, which is a Phase Contrast (PC) application that generates an image contrast related to the shear stiffness of soft tissue.

Indications for use

MR-Touch is a software and hardware option intended for use with GE MR systems. It is indicated for magnetic resonance imaging of the human body in adults.

MR-Touch generates transverse sectional information related to the relative stiffness of soft tissue. It consists of hardware as well as acquisition and reconstruction software. The hardware components induce vibrations into the scan subject. The MR-Touch acquisition software is an evolutionary improvement to the GRE (1.5T) sequence. The sequence synchronizes the induced vibrations to acquire a series of phase-contrast images over time. The phase-contrast imaging technique measures motion or displacement. The displacement from the induced vibrations is detected using the time-series of phase-contrast images. The displacement information is reconstructed and presented as strain wave and relative stiffness images.

When used with a GE MR system, MR-Touch is capable of producing transverse images of internal body structures such as muscle and liver.

When interpreted by a trained physician, these images may provide information that can be useful in determining a diagnosis.

Considerations

Important: MR Touch has only been evaluated for use on adults. There is insufficient information to establish the safety and effectiveness of MR Touch for use on pediatric patients.
MR-Touch is performed by synchronizing the Gradient Echo (1.5T pulse sequence used) with acoustic waves that are applied with an external MR-Touch Device.The pulse sequence is modified with an oscillating Motion Encoding Gradient (MEG). The external acoustic driver is triggered by the PSD so that the MEG is synchronized with the external acoustic wave. The duration of the MEG is the same as the period of the mechanical vibration. A phase shift occurs in the MR signal, which correlates with the mechanical excursion. An algorithm is used to derive a relative stiffness map and wave images from the phase images.

MR-Touch acquisition generates the following image types: magnitude, phase maps, wave maps, and an attenuation map. Six relative stiffness images are reconstructed for each slice location. The relative stiffness images are reconstructed in color and grey scale, and in masked and un-masked versions. Mask portion is depicted as a checkerboard pattern on the image. It is created to identify regions that should not be included in ROI measurements.

Table 1. MR-Touch image maps
Image mapImage map
Figure 1. Anatomic/Magnitude image
Figure 2. Phase map: 4 phases
Figure 3. Grey Elastogram, no mask
Figure 4. Grey Elastogram, with mask
Figure 5. Color Elastogram, no mask, scale 0-8K
Figure 6. Color Elastogram, with mask, scale 0-8K
Figure 7. Color Elastogram, no mask, scale 0-20K
Figure 8. Color Elastogram, with mask, scale 0-20K
Figure 9. Color wave image: 4 phases
Figure 10. Attenuation map

MR-Touch measurement units

The MR-Touch functional maps have the following units of measurement.

Table 2. MR-Touch measurement units
MapsUnits
MR Touch-ElastogramPa
MR-Touch-Wave Imagesmm
MR-Touch-Elastogram + MaskPa
MR Touch-attenuation1/m

READY View protocols that use MR-Touch scan data

  • MR-Touch
  • MR Liver