Risks And Potential Interactions; Image Artifacts And Distortion - Boston Scientific ImageReady Mode D'emploi

Risks and Potential Interactions

The Spectra WaveWriter SCS System with ImageReady MRI Technology has been shown through non-
clinical testing to minimize the potential interactions with MRI when the appropriate conditions described
in this manual are followed. Risks related to SCS implant geometries or locations outside the directions for
use have not been evaluated.
The known potential residual risks include:
• The Spectra WaveWriter SCS System IPG may move within the implant pocket or become warm,
which may cause patient discomfort.
• Induced electrical stimulation of the patient could cause an uncomfortable sensation.
Factors that increase these residual risks include, but are not limited to, the following:
• Lead lengths longer than 50 cm and/or use of extensions, adapters, or splitters may increase the
risk of stimulation or jolting sensations.
• Performing MRI scans above Normal Operating Mode exposure limits or in scanners with higher
maximum slew rate limits may increase the risk of stimulation or uncomfortable sensations or
implant pocket temperature rise.
• Any component of the Spectra WaveWriter SCS System (such as the implanted Leads, IPG, etc)
extending into the Transmit/Receive RF Head Coil or within 10cm of the Head Coil may increase
the risk of stimulation or jolting sensations.

Image Artifacts and Distortion

The implanted system has minimal image distortion when the implanted device is out of the field of view.
In general, significant image distortion can result from the presence of the device within the field of view.
These factors must also be considered when interpreting the MRI images.
When a MRI scan is performed under the conditions listed in this manual, no component of the implanted
system (stimulator, leads etc) should be within 10 cm of the head coil. The implanted devices are not
expected to be within the field of view. Image artifacts and distortion resulting from the presence of the
devices are expected to be minimal.
If image artifacts are observed, they may be minimized by careful choice of pulse sequence parameters
and location of the imaging plane. However, the reduction in image distortion obtained by adjustment of
pulse sequence parameters will usually compromise signal-to-noise ratio.
The following general principles should be followed:
• Use imaging sequences with stronger gradients for both slice and read encoding directions. Use
higher bandwidth for both radio-frequency pulse and data sampling.
• Choose an orientation for the read-out axis that minimizes the appearance of in- plane distortion.
• Use a shorter echo time for gradient echo technique, whenever possible.
ImageReady MRI Guidelines for Spectra WaveWriter Spinal Cord Stimulator System
Warnings, Limitations, and Risks
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