IDEV recommends that patients register the conditions under which the implant can be scanned safely, listed below, with the MedicAlert Foundation or equivalent organization.

SUPERA® Interwoven Self-Expanding Nitinol Stent Transhepatic Biliary System

This device is classified as MR Conditional.

The SUPERA® Interwoven Self-Expanding Nitinol Stent Transhepatic Biliary System is indicated for palliative treatment of biliary strictures produced by malignant neoplasms.

CAUTION: This device is not yet approved by the FDA for distribution in the United States for peripheral vascular disease.

Non-clinical testing has demonstrated the SUPERA® Biliary Stent is MR Conditional. It can be scanned safely, immediately after placement, under the following conditions:

• Static magnetic field of 1.5 or 3.0 Tesla
• Highest spatial gradient magnetic field of 2,500 Gauss/cm or less (extrapolated value from physical testing at 471 Gauss/cm)
• Maximum MR system reported whole body averaged specific absorption rate (SAR) of 2 W/kg for 15 minutes of scanning (per pulse sequence), operating in the Normal Operating Mode (i.e., MR system mode of operation where there is no physiological stress to the patient)

In non-clinical testing of individual stents and testing of two overlapped stents totaling 270mm in length, the SUPERA® Biliary Stent(s) produced a temperature rise of less than 4.1°C at a maximum MR system reported whole body averaged specific absorption rate (SAR) of 2 W/kg as assessed by calorimetry, for 15 minutes of MR scanning (per pulse sequence) at both 1.5 Tesla and 3.0 Tesla in an MR scanner (GE Signa whole body coil, model #46-258170G1 for 1.5T; and GE Signa HDx 3T whole body scanner, software version 15/LX/MR (15.0.M4.0910a) for 3.0T).

The effect of heating in the MRI environment for stents with fractures is unknown.

Artifacts

The maximum artifact measured extended ~2 cm from the stent, and the image of the stent lumen was obscured in the tests. MR image quality may be compromised if the area of interest is in the same area or relatively close to the position of the SUPERA® Biliary Stent. Therefore, it may be necessary to optimize MR imaging parameters for the presence of this implant.

SUPERA® Interwoven Self-Expanding Nitinol Stent Superficial Femoral Artery (SFA) System

This device is classified as MR Conditional.

CAUTION: This is an investigational device limited by Federal Law to investigational use. This device is not yet approved by the FDA for distribution in the United States for peripheral vascular disease.

Non-clinical testing has demonstrated that the IDEV SUPERA® stent is MR Conditional. Patients with the SUPERA® stent up to a total length of 270 mm in the SFA may be safely imaged whole body cylindrical MR systems under the following conditions:

• Static magnetic field of 1.5 Tesla or 3.0 Tesla.
• Spatial gradient field of 1000 Gauss/cm or less.
• For landmarks above the umbilicus, the whole body SAR must be less than 2 W/kg.
• For landmarks below umbilicus, the whole body SAR must be less than 1 W/kg.
• The legs of the patient should not be touching during the procedure.
• All MRI scans must be performed in normal operating mode.

Vascular, 3.0 Tesla Temperature Rise

Non-clinical testing of RF induced heating was performed at 128 MHz in a GE Signa HD x 3.0 T MR system, software version 4\LX\MR. Stent lengths from 40 mm to 200 mm were tested, as well as an overlapped length of 270 mm. The testing was based upon ASTM F2182, with the stents in a location and orientation in the phantom that produced the worst-case heating. RF power was applied for 15 minutes and the conductivity of the phantom material was approximately 0.5 S/m.  The calculated phantom average SAR ranged from 2.7 to 3.0 W/kg and the local SAR at the site of the stents ranged from 7.7 to 8.7 W/kg. The maximal measured temperature rise at the ends of the stents, when scaled to a local SAR of 2W/kg, was 3.0 °C.

Calculation of in-vivo heating of a SUPERA^® stent in the SFA and iliac artery in a digitized human model using worst-case assumptions for the interactions of the electromagnetic fields in the body with the stent resulted in a worst-case in-vivo rise of 5.2°C in the SFA and 6.5°C in the iliac artery for 15 minutes of scanning and whole body SAR of 2 W/kg for landmarks above umbilicus and 2.8 °C in the SFA and 5.0 °C in the iliac for 15 minutes of scanning and whole body SAR of 1W/kg for landmarks below umbilicus.  These rises were for an 80 mm stent; other stent lengths yielded lower temperature rises. The actual in-vivo rise is expected to be less, as this calculation did not include the cooling due to blood flow in the lumen of the stent and blood perfusion in the tissue outside the stent.

Vascular, 1.5 Tesla Temperature Rise

Non-clinical testing of RF induced heating was performed at 64 MHz in a GE Signa whole body coil. Stent lengths from 40 mm to 200 mm were tested. The testing was based upon ASTM F2182, with the stents in a location and orientation in the phantom that produced the worst-case heating. RF power was applied for 15 minutes and the conductivity of the phantom material was approximately 0.5 S/m. The calculated phantom average SAR ranged from 2.1 to 2.5 W/kg and the local SAR at the site of the stents ranged from 4.0 to 6.2 W/kg. The maximal measured temperature rise at the ends of the stents, when scaled to a local SAR of 2 W/kg, was 5.1 °C.

Calculation of in-vivo heating of a SUPERA^® stent in the SFA and iliac artery in a digitized human model using worst-case assumptions for the interactions of the electromagnetic fields in the body with the stent resulted in a worst-case in-vivo rise of 6.4 °C in the SFA and 5.2 °C in the iliac artery for 15 minutes of scanning and whole body SAR of 2 W/kg for landmarks above umbilicus and 5.4 °C in the SFA and 5.7 °C in the iliac for 15 minutes of scanning and whole body SAR of 1 W/kg for landmarks below umbilicus. These rises were for 150 mm and 180 mm stents; other stent lengths yielded lower temperature rises. The actual in-vivo rise is expected to be less, as this calculation did not include the cooling due to blood flow in the lumen of the stent and blood perfusion in the tissue outside the stent.

Magnetic Force and Torque

The magnetic force was measured using the deflection technique in a 3 T whole body MR system to be less than 6% of the gravity force. Magnetic torque was qualitatively determined to be less than that exerted by gravitational pull.  Patients will not be at added risk from magnetic force and torque exerted on the stent during MRI.

Image Artifact

Image distortion was measured in the 3 T GE system using a protocol consistent with that prescribed in ASTM F2119-01.  Software Version was 14\LX\MR and the software release was 14.0.M5.0737.f.1.  The maximal artifact in the measurements extended about 2 cm from the stent.  The image of the lumen was obscured in the tests.  It may be necessary to optimize MR imaging parameters for the presence of this implant.