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Table 2 MRI Patient and Scanner Conditions for Clinically Released MR Conditional Systems in the United States or the European Community.

From: Magnetic resonance imaging in patients with cardiac pacemakers: era of "MR Conditional" designs

System Medtronic EnRhythm MRI™ SureScan™ Pacing System St. Jude Medical™ MR Conditional Pacing System Biotronik ProMRI™ MR Conditional Pacing System
Approval United State (FDA appoval)
European Community (CE approval)
European Community (CE approval) European Community (CE approval)
Studies Wilcoff et al. [81]
Forleo et al. [82]
Advisa MRI Study [83]. (In process)
Accent MRI Study [145]. (In process)  
Implant site Left or right pectoral region Left or right pectoral region Chest area.
Patient's height at least 1.4 meters
Limitations related to other devices/leads No active or abandoned medical devices, leads, lead extenders or adaptors No abandoned cardiac hardware including leads, lead extenders, or lead adaptors No other pacemakers or ICDs, leads no longer in use, lead adapters, lead extension
Implant timing prior to MRI At least six weeks Stable pacing capture threshold values At least 6 weeks.
Acceptable lead parameters for MRI Capture thresholds of ≤ 2.0 V at a pulse width of 0.4 ms
Impedance of ≥ 200 and ≤ 1500 Ohms
No diaphragmatic pacing at 5.0 V at a pulse width of 1.0 ms
Capture threshold values of ≤ 2.5 V at 0.5. ms pulse width
Lead impedance measurements within the programmed lead impedance limits
No diaphragmatic stimulation at a pacing output of 5.0 V or 7.5 V and at a pulse width of 1.0 ms if device will be programmed to an asynchronous pacing mode when MRI Settings are enabled
Capture threshold ≤ 2.0 V at 0.4 ms pulse width
Lead impedance is between 200 and 1500 Ohms •
Battery charging status: at least 30%
Programming for MRI MR conditional programming modes MR conditional programming modes MR conditional programming modes
Device Identifiers Pulse generator radiopaque marking with a unique symbol and three letter code
Unique radiopaque lead helix design
A radio-opaque MRI symbol is present on all implanted St. Jude Medical™ MR Conditional pacing system components
Radiopaque MR Conditional lead marker
Pulse generator radiopaque marking.
No lead radiopaque identifier
Scanner 1.5 Tesla cylindrical bore MR system 1.5 Tesla horizontal closed bore MR system 1.5 Tesla cylindrical bore MR system
Landmark isocenter of RF coil United States: Superior to C1 or inferior to T12
Ensura MRI™ SureScan™ Pacing System and Advisa DR MRI™ SureScan™ pacemaker labeling has no restrictions on chest scans outside the United States
Contraindication to use of local transmit-only coils or local transmit and receive coils placed directly over the pacing system Maximum allowed positioning mark for the isocenter starting from the foot at the hip bone level. and maximum allowed positioning mark for the isocenter from the top of the skull at the level of the eyes).
Patient Positioning Contraindication to lateral decubitus patient positioning Must not be positioned on side Dorsal position only.
Scanner Mode Scanner in' the normal operating mode (defined as the mode of operation of the MR system in which none of the outputs have a value that cause physiological stress to patients) Scanner in the normal operating mode or First Level Controlled operating mode The overall MR scanning time accumulated from the imaging times as displayed by the MRI scanner must not exceed 30 minutes
The total accumulated length of examination for the pacing system must be below 10 hours
Radiofrequency Energy Maximum gradient slew rate ≤ 200 T/m/s per axis
Whole body specific absorption rate (SAR) levels ≤ 2 W/kg
Head SAR ≤ 3.2 W/kg
Maximum gradient slew rate ≤ 200 T/m/s per axis
Whole body specific absorption rate (SAR) ≤ 4.0 W/kg
Head SAR ≤ 3.2 W/kg
Maximum gradient slew rate ≤ 200 T/m/s per axis
Whole body specific absorption rate (SAR) ≤ 2.0 W/kg
Head SAR ≤ 3.2 W/kg