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MobiFlex on 1.5T

Application Tip
Nijenhuis, Marco Philips Healthcare
van den Heuvel, Martina Philips Healthcare

MobiFlex is a contrast-enhanced MRA technique which helps to visualize the peripheral vessels from abdominal aorta down to the pedal arch using the moving-table technique.

 

Using the MobiFlex ExamCard, the examination can be performed in a simple and quick way providing optimum image quality. Viewing can be easily done with the MobiView package which is available within the Advanced Viewing Environment.

Tip 1: Ensuring smoothly fused images when modifying parameters per station

With MobiFlex, it is possible to adjust all imaging parameters per station including acquisition and reconstruction matrix.

If the ExamCard is modified such that the amount of data on a certain station increases too much, the following message will show up:  


 "This can lead to discontinuities between stations."


This message indicates that discontinuities between stations could appear which might be visible in the fused images. For optimum image quality, it is recommended to solve the problem prior to starting the ExamCard:

 

Reduce the 'reconstruction matrix'

Change the 'reconstruction matrix' to the same values as the 'acquisition matrix' or to any other value (in previous releases: to 128, 256, 512, 1024 only) in order to reduce the amount of data.

 

Set the 'reconstruction mode' to 'immediate'

The 'reconstruction mode' is set to 'Real-time' within the MobiFlex ExamCard.
Set this parameter to 'immediate' so that the scan(s) will be reconstructed immediately after scan completion, and the problem is solved.

Tip 2: Use 'PicturePlus' image enhancement prior to fusing stations

'PicturePlus' is a filter that reduces noise and artifacts, thereby enhancing the anatomical structures in the images. It uses an intelligent algorithm of smoothing and edge enhancement, e.g. background noise is smoothed while vessels are sharpened.

As this function is not available for fused images, it has to be applied prior to fusing:

 

  • Use 'PicturePlus' for the required images.
  • Fuse the images within the MobiView package afterwards.

Tip 3: Disable immediate subtraction to obtain post-contrast images (instead of subtracted images)

Within the MobiFlex ExamCard, immediate subtraction is enabled. This means that after scan completion, the pre-contrast images and the subtracted images are available, but not the post-contrast images.

If the post-contrast images are required, the imaging parameter 'Immediate subtraction' has to be set to 'No'.

In order to generate subtracted images in a quick and easy way in this case:

  • Select the source images.
  • Enter the 'Dynamic Subtraction' tool.
  • Checkmark all stations.  

Tip 4: Feet positioning with the Synergy PV (Peripheral Vascular) coil

  • Position the patient's heels within the lower coil element (see orange marked area on image below).

 

  • When the upper part of the coil is attached to the coil base, the feet have to stick out of the coil. Make sure that the pedal arch of both feet is still covered by the coil (within coil sensitivity area).

 

  • Further immobilize the feet and lower leg with some cushions in order to get the best subtracted images for Maximum Intensity Projection (MIP) generation.

 

  • Do NOT use the wide holes in the upper part of the PV coil for feet positioning.
    Patients will always stretch out their feet and as a consequence the coil elements from the upper and lower part are not facing each other well. This will influence in particular the signal at the transition of the different stations.  
Synergy PV coil Position the patient's heels just within the lower coil element (see orange marked area).Synergy PV coil Patient strapped within coil.Synergy PV coil Wide holes in upper part of the coil.
Synergy PV coil
Synergy PV coil
Synergy PV coil
Position the patient's heels just within the lower coil element (see orange marked area).
Patient strapped within coil.
Wide holes in upper part of the coil.

Tip 5: Switch off image shutter with FOV larger than 450 mm

With a FOV larger than 450 mm (at least 451 mm), an additional geometry parameter appears to switch off the system's image shutter.


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Apr 12, 2005

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Application Tip
Achieva 1.5T, Ingenia 1.5T, Intera 1.5T
Release 1, Release 10, Release 11, Release 3, Release 4, Release 5, Release 9
Peripheral MRA, Vascular
 

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