MAGNETIC RESONANCE IMAGING (MRI) INFORMATION

Non-clinical testing and analysis have demonstrated that when used in the neurovasculture, Stryker Detachable Coils are MR Conditional. A patient with Stryker Detachable Coils can be safely scanned immediately after placement of the coils, under the following conditions:

• Static magnetic field of 1.5 or 3.0 Tesla
• Spatial gradient field up to 2500 Gauss/cm (25 Tesla/m)
• Normal operational mode for gradients and SAR (maximum whole body averaged specific absorption rate (SAR) of lower than 2.0 W/kg and maximum head SAR of lower than 3.2 W/kg) for a total active MR scan time (with RF exposure) of 15 minutes or less per scan sequence.

In an analysis based on the temperature rises in non-clinical testing of spherical aneurysm models, the Detachable Coils were determined to produce an in-vivo temperature rise of 2°C or less for 15 minutes of MR scanning in normal mode operation in 1.5 T and 3 T MR systems. The Detachable Coils should not migrate in this MRI environment.

Temperature testing was not conducted in arteriovenous malformations or fistulae models. MR image quality may be compromised if the area of interest is in the same area or relatively close to the position of the device. Therefore, it may be necessary to optimize MR imagining parameters for the presence of this implant. 

Non-clinical testing and analysis have demonstrated that when used in peripheral vasculature Stryker Detachable Coils are MR Conditional. A patient can be safely scanned immediately after placement of the coils, under the following conditions:

• Static magnetic field of 1.5 and 3.0 Tesla
• Spatial gradient field up to 2500 Gauss/cm (25 Tesla/m)
• Normal operational mode for gradients and SAR (maximum whole body averaged specific absorption rate (SAR) of lower than 2.0 W/kg and maximum head SAR of lower than 3.2 W/kg) for a total of active MR scan time (with RF exposure) of 15 minutes or less per scan sequence.

In an analysis based on the temperature rises in non-clinical testing of a bundle of 30 test coils with a length of 109mm and the calculated SAR in the patient during MR scan, the test coils were determined to produce an in-vivo temperature rise of 7.4°C or lower for 15 minutes of MR scanning in normal operational mode in 1.5 T and 3 T MR systems. The Detachable Coils should not migrate in this MRI environment. The SAR limit of 2 W/kg applies only for coil placement in the torso. A reduction of SAR limits may be appropriate for coil placement in the legs or arms.

MR image quality may be compromised if the area of interest is in the same area or relatively close to the position of the device. Therefore, it may be necessary to optimize MR imaging parameters for the presence of this implant.

Non-clinical testing and analysis have demonstrated that Neuroform Stent is MR Conditional alone, or when overlapped with a second stent, and adjacent to a Stryker Neurovascular coil mass. A patient with Neuroform Stent can be safely scanned immediately after placement of this implant, under the following conditions:

• Static magnetic field of 1.5 and 3.0 Tesla
• Spatial gradient field up to 2500 Gauss/cm (25 Tesla/m)
• Normal operational mode for gradients and SAR (maximum whole body averaged specific absorption rate (SAR) of lower than 2.0 W/kg and maximum head SAR of lower than 3.2 W/kg) for a total active MR scan time (with RF exposure) of 15 minutes or less per scan sequence.

In an analysis based on the temperature rises in non-clinical testing of stents and the calculated SAR in the patient during an MR scan, Neuroform Stents were determined to product an in-vivo temperature rise of 4.0^oC or lower for 15 minutes of MR scanning in normal operational mode in 1.5 T and 3 T MR systems. The Neuroform Stent should not migrate in this MRI environment.

MR image quality may be compromised if the area of interest is in the same area or relatively close to the position of the device.

In Spin Echo and Gradient Echo sequence evaluations Neuroform stent image artifact extended approximately 2mm from the device. Lumen of the stent was partially obscured by the artifact. Therefore, it may be necessary to optimize MR imaging parameters for the presence of this implant.

MAGNETIC RESONANCE IMAGING (MRI) INFORMATION

The Surpass™ Flow Diverter was determined to be MR Conditional.Non-clinical testing demonstrated that the Surpass Flow Diverter is MR Conditional. A patient withthis device can be scanned safely immediately after placement under the following conditions:

Static Magnetic Field
Static magnetic field of 3-Tesla or lessMaximum spatial gradient magnetic field of 2,000-Gauss/cm or less*MR system operating in the First Level Controlled Mode (i.e., the mode of operation of the    MR system in which one or more outputs reach a value that may cause physiological stress to patients which needs to be controlled by medical supervision) at a whole body averaged SAR of 4.0-W/kg for 15 min. of scanning (i.e., per pulse sequence)

*Translational Attraction
The measured value of the highest spatial gradient used for the assessment of translational attraction for the Surpass Flow Diverter implant was 720-Gauss/cm. The calculated acceptable level for the spatial gradient magnetic field was based on consideration of this value along with the magnetic field strength at this position, the measured deflection angle for this implant, and includes a margin of safety.

MRI-Related Heating
In non-clinical testing, the Surpass Flow Diverter produced the following temperature rise during MRI performed for 15-min of scanning (i.e., per pulse sequence) in the 3-Tesla (3-Tesla/128-MHz, Excite, HDX, Software 14X.M5, General Electric Healthcare, Milwaukee, WI) MR system:Highest temperature Change + 2.3°CTherefore, the MRI-related heating experiments for the Surpass Flow Diverter at 3-Tesla using a transmit/receive RF body coil at an MR system reported whole body averaged SAR of 2.9 -W/kg (i.e., associated with a calorimetry measured whole body averaged value of 2.7-W/kg) indicated that the greatest amount of heating that occurred in association with these specific conditions was equal to or less than +2.3°C. This value scaled is 3.4°C when scaled to a whole body averaged SAR of 4.0-W/kg.

Artifact Information
MR image quality may be compromised if the area of interest is in the exact same area or relatively close to the position of the Surpass Flow Diverter. Therefore, optimization of MR imaging parameters to compensate for the presence of this device may be necessary. The maximum artifact size (i.e., as seen on the gradient echo pulse sequence) extends approximately 10-mm relative to the size and shape of the Surpass Flow Diverter.

Pulse Sequence T1-SE T1-SE GRE GRE

Signal Void Size 544-mm² 82-mm² 1,104-mm² 220-mm²  

Plane Orientation Parallel Perpendicular Parallel Perpendicular  

Overlapping Stents
The effect of heating in the MRI environment for overlapping stents is not known.

Non-clinical testing and analysis have demonstrated the Target Detachable Coils are MR Conditional. A patient with this device can be safely scanned immediately after placement of the coils in an MR system meeting the following conditions:

• Static magnetic field of 3.0 T or less
• Maximum spatial gradient magnetic field of 2500 gauss/cm (25 T/m)
• Maximum MR system reported, head specific absorption rate (SAR) < 3.2 W/kg and whole body averaged SAR < 2 W/kg (Normal operating mode)

Under the scan conditions defined above, the Target Detachable Coils are expected to produce a maximum temperature rise of less than 4°C after 15 minutes of continuous scanning.

In non-clinical testing, the image artifact caused by the device extends approximately 12 mm from the Target Detachable Coils when imaged with a gradient echo pulse sequence and a 3.0 T MRI system.

Target Detachable Coils are made from non-magnetic platinum-tungsten alloy and should not migrate in the magnetic field. The health state of the patient or the presence of other implants may require reduction of the MRI limits.

Non-clinical testing and analysis have demonstrated the Target Detachable Coils are MR Conditional. A patient with this device can be safely scanned immediately after placement of the coils in an MR system meeting the following conditions:

• Static magnetic field of 3.0 T or less
• Maximum spatial gradient magnetic field of 2500 gauss/cm (25 T/m)
• Maximum MR system reported, head specific absorption rate (SAR) < 3.2 W/kg and whole body averaged SAR < 1 W/kg (Normal operating mode)

Under the scan conditions defined above, the Target Detachable Coils are expected to produce a maximum temperature rise of less than 2°C after 15 minutes of continuous scanning.

In non-clinical testing, the image artifact caused by the device extends approximately 13 mm from the Target Detachable Coils when imaged with a gradient echo pulse sequence and a 3.0 T MRI system.

Target Detachable Coils are made from non-magnetic platinum-tungsten alloy and should not migrate in the magnetic field. The health state of the patient or the presence of other implants may require reduction of the MRI limits.

Non-clinical testing and analysis has demonstrated that the Wingspan® Stent is MR Conditional alone, or when overlapped with a second stent. A patient with this device can be safely scanned immediately after placement of this implant, in an MR system meeting the following conditions:

• Static magnetic field of  1.5T and 3.0T only 
• Maximum spatial gradient magnetic field of 2,500 gauss/cm (25 T/m) or less
• Maximum MR system reported, whole body averaged specific absorption rate (SAR) of 2 W/kg (Normal Operating Mode) and head averaged SAR of 3.2 W/kg

Under the scan conditions defined above, the Wingspan Stent is expected to produce a maximum temperature rise of 4ºC after 15 minutes of continuous scanning.  

In non-clinical testing, the image artifact caused by the device extends up to 2 mm from the Wingspan stent when imaged with a spin echo pulse sequence and a 3 Tesla MRI system.  The artifact may obscure the device lumen.