AAMI PC76 2021
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ANSI/AAMI PC76:2021, Active implantable medical devices-Requirements and test protocols for safety of patients with pacemakers and ICDs exposed to magnetic resonance imaging
| Published By | Publication Date | Number of Pages |
| AAMI | 2021 | 136 |
Provides requirements and test protocols for implantable pacemakers and ICDs exposed to magnetic resonance imaging. Physicians are increasingly using magnetic resonance imaging as tool for differential diagnostic, thus exposing pacemakers and ICD patients to such equipment. Current product standards for implantable pacemakers and ICDs do not include requirements and test protocols for implantable pacemakers and ICDs, which would ensure patient safety during such procedures.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 1 | ANSI/AAMI PC76:2021; Active implantable medical devices—Requirements and test protocols for safety of patients with pacemakers and ICDs exposed to magnetic resonance imaging |
| 3 | Title page |
| 4 | AAMI Standard Copyright information |
| 5 | Contents |
| 10 | Committee representation |
| 11 | Foreword |
| 13 | 1 Scope 2 Normative references |
| 14 | 3 Terms and definitions |
| 18 | 4 Symbols and abbreviated terms 5 General requirements for non-implantable parts 6 Global malfunction |
| 20 | 6.1 Pacing monitoring in radiated environment |
| 21 | 7 General considerations for application of the tests of this document |
| 22 | 8 Protection from harm to the patient from lead electrode heating 8.1 General 8.2 Hotspot determination 8.3 MRI RF lead modelling framework |
| 23 | 8.3.1 RF birdcage coils and excitation 8.3.1.1 Coil types 8.3.1.2 Coil excitation 8.3.1.3 Field rotation |
| 24 | 8.3.2 Human body library 8.3.3 Body position in bore (landmark) 8.3.4 Lead pathways 8.3.4.1 Device locations 8.3.4.2 Lead tip locations |
| 25 | 8.3.4.3 Lead pathway definition 8.3.5 RF electrical lead model 8.4 Model validation |
| 26 | 8.4.1 In-vitro lead model validation 8.4.1.1 Phantom selection 8.4.1.2 Tissue simulating medium (TSM) |
| 29 | 8.4.1.3 RF coil and excitation 8.4.1.4 Lead paths |
| 30 | 8.4.1.5 Phantom landmarks 8.4.1.6 In-vitro lead model validation data and analysis 8.4.1.6.1 Simulations 8.4.1.6.2 Measurements 8.4.1.6.3 Data comparison and analysis |
| 31 | 8.5 Human RF hotspot power prediction 8.5.1 Human body simulations 8.5.2 Etan extraction |
| 32 | 8.5.3 Lead model simulation and pdf 8.5.4 Uncertainty analysis 8.6 Physiologic response |
| 33 | 8.6.1 CEM43 (cumulative equivalent minutes at 43 C) 8.6.2 Change in pacing capture threshold (∆PCT) 8.6.2.1 Acute versus chronic insult response 8.6.2.2 ∆PCT versus power data set |
| 34 | 8.6.2.2 Power level determination 8.6.2.2.1 Standard leads 8.6.2.2.2 Custom power delivery devices |
| 35 | 8.6.2.2.3 Power delivery signal loss 8.7 Combining simulated power profile with physiologic response 8.7.1 CEM43 8.7.2 ∆PCT 8.8 Requirement 8.8.1 CEM43 |
| 36 | 8.8.2 ∆PCT 8.8.2.1 Acute insult response requirement while in MRI mode |
| 37 | 8.8.2.2 Chronic insult response requirement 8.9 Cumulative effect 9 Protection from harm to the patient from device heating 9.1 Test equipment 9.2 Test method |
| 38 | 9.2.1 Gradient induced temperature rise due to eddy currents on the device surface (without leads) 9.2.1.1 Tier 1: Temperature measurement in TSM 9.2.1.2 Tier 2: Power method |
| 40 | 9.2.2 RF induced temperature rise from injected RF |
| 41 | 9.2.3 RF Induced Temperature Rise from local E-field at the CAN 9.2.4 Reporting the results from injected and radiated test 9.3 Requirement 10 Protection from harm to the patient caused by gradient-induced vibration 10.1 Test Method |
| 42 | 10.2 Magnetic resonance environment 10.2.1 Magnetic field parameters (B0 and dB/dt) 10.2.1.1 CRM devices labeled for a maximum slew rate 10.2.1.2 CRM devices labeled for a maximum slew rate of 200 T/m/s per axis |
| 43 | 10.2.2 Maximum clinical excitation 10.2.3 Test duration and temperature 10.3 General test procedure 10.3.1 Device setup in an MR scanner 10.3.2 Test methods 10.3.3 Device monitoring setup 10.3.4 Tier 1 Monitoring (if a scanner is used) 10.3.5 Method 2 Monitoring (if a shaker table is used) 10.4 Assess for device malfunction and damage |
| 44 | 10.5 Assess for tissue damage 11 Protection from harm to the patient caused by B0-induced force 11.1 B0 and B Measurements 11.2 B0 and B Measurements 11.2.1 Determining the Z-axis location 11.2.2 Determining maximum dB/dz |
| 45 | 11.3 Lead force measurements 11.3.1 Lead body and distal end force measurements |
| 46 | 11.3.2 Lead proximal connector force measurement 11.4 Device force measurements 11.4.1 Device force measurement system limitations |
| 47 | 11.5 Force requirements 11.5.1 Tier 1 – Device force limit 11.5.2 Tier 2 – Device force limit |
| 48 | 11.5.3 Lead force limit 11.6 Extrapolating the maximum |B| 11.6.1 Extrapolation calculation |
| 49 | 11.6.2 Labeling requirements 12 Protection from harm to the patient caused by B0-induced torque 12.1 ASTM F2213-17 12.2 Current induced torque 12.3 Lead torque measurements 12.3.1 Lead proximal connector torque measurement 12.3.2 Lead body and distal end torque measurements |
| 50 | 12.4 Device torque measurements 12.5 Torque requirements 12.6 Device torque limit 13 Protection from harm to the patient caused by gradient-induced extrinsic electric potential 13.1 Introduction |
| 51 | 13.2 General requirements |
| 54 | 13.3 Annex E, Gradient induced probability of UCS calculation method |
| 55 | 13.4 PG lead connector, gradient pulse leakage test |
| 57 | 13.5 PG internal circuit, gradient pulse leakage test 13.5.1 Test equipment 13.5.2 Test signal |
| 58 | 13.5.3 Tier 1- Combined gradient induced charge measurement test procedure |
| 60 | 13.5.4 Tier 2- Separate transient gradient induced charge and steady state current measurement test procedure 13.5.4.1 Gradient induced charge measurement test procedure |
| 61 | 13.5.4.2 Gradient induced current measurement test procedure |
| 62 | 13.6 Gradient rectification test 13.6.1 Test equipment |
| 63 | 13.6.2 Test signal |
| 64 | 13.6.3 Gradient induced rectification measurement test procedure |
| 65 | 13.7 Gradient pulse distortion of PG pace output test 13.7.1 Test equipment 13.7.2 Test signal 13.7.3 Gradient induced PG output distortion test procedure |
| 67 | 13.8 PG Test voltages and test case definition |
| 68 | 13.8.1 Tier 2 Test voltage definitions and values 13.8.2 Tier 3 Test voltage determination |
| 69 | 13.8.2.1 Gradient coils and excitation 13.8.2.1.1 Coil types 13.8.2.1.2 Gradient coil excitation 13.8.2.2 Human body library 13.8.2.3 Body position in bore (landmark) 13.8.2.4 Lead pathways 13.8.3 Pacemaker test cases |
| 70 | 13.8.4 ICD Test cases 13.9 PG Test configurations |
| 71 | 13.9.1 Single chamber pacemaker test connections |
| 72 | 13.9.2 Dual chamber pacemaker test connections |
| 73 | 13.9.3 Three chamber, bi-ventricular pacemaker 13.9.4 Single chamber, single coil ICD |
| 75 | 13.9.5 Dual chamber, dual coil ICD 13.9.6 Three chamber, bi-ventricular, dual coil ICD |
| 76 | 13.10 Tissue interface network |
| 78 | 14 Protection from harm to the patient caused by B0-induced malfunction 14.1 General 14.1.1 Scope 14.1.2 Testing basis |
| 79 | 14.2 CIED classes |
| 80 | 14.3 Static field testing 14.3.1 Scope 14.3.2 Compliance criteria 14.3.3 B0 field generation 14.3.4 Test conditions 14.4 Test procedures |
| 81 | 14.4.1 Class 0 test 14.4.1.1 Test procedure 14.4.2 Class 1 test 14.4.2.1 Test procedure 14.4.3 Class 2 test |
| 82 | 14.4.3.1 Test procedure 14.5 Test equipment 14.5.1 Field generation 14.5.2 Phantom and tissue simulating medium 14.5.3 CIED monitoring apparatus 14.6 Uncertainty assessment 15 Protection from harm to the patient caused by RF-induced malfunction and RF rectification 15.1 General 15.2 Hazard definition/mechanism 15.3 Objective |
| 83 | 15.4 Assumptions 15.5 Test method 15.5.1 Test environment 15.5.2 RF Antenna test conditions |
| 84 | 15.5.2.1 Modelling method |
| 85 | 15.5.2.2 Model validation 15.5.2.2.1 15.5.2.2.1 Simulation parameters |
| 86 | 15.5.2.2.2 Device geometry 15.5.2.2.3 Device material properties 15.5.2.2.4 Device terminating impedances 15.5.3 Injection test setup |
| 87 | 15.5.4 Determination of test conditions |
| 88 | 15.5.4.1 RF-level measurement device 15.5.4.2 MRI RF lead modelling framework 15.5.4.3 Model validation 15.5.4.4 RF level prediction in human 15.5.4.5 RF phase conditions 15.5.5 Test signal |
| 90 | 15.5.6 Application of the test signal 15.5.7 Rectification and malfunction test procedure |
| 91 | 15.5.7.1 Device damage test procedure 16 Protection from harm to the patient caused by gradient-induced malfunction 16.1 Introduction |
| 92 | 16.2 General requirements 16.3 Selecting radiated and injected test methods 16.4 Radiated immunity test 16.4.1 General |
| 93 | 16.4.2 Test equipment |
| 94 | 16.4.3 Radiated test signal |
| 96 | 16.4.4 Pacemaker test cases 16.4.5 ICD test cases |
| 97 | 16.4.6 Test procedure 16.5 Injected immunity test 16.5.1 General 16.5.2 Test equipment 16.5.3 Injected test signal |
| 100 | 16.5.4 Pacemaker test cases |
| 101 | 16.5.5 ICD test cases 16.5.6 Test procedure 16.5.7 Test configurations |
| 102 | 17 Combined fields test 17.1 Test equipment 17.2 Test setup |
| 104 | 17.3 System fixation |
| 107 | 17.4 Test procedure 17.4.1 Before MR exposure 17.4.2 During MR exposure |
| 108 | 17.4.3 After MR exposure 17.5 Compliance criteria |
| 109 | Annex A (informative) RF injection method utilizing standard leads A.1 General |
| 111 | A.2 Measurement to address the concern of common mode at 500 kHz |
| 112 | Annex B (informative) Use of standard production leads to deliver a target RF power at 64 MHz to the myocardium in an animal test B.1 General B.2 Procedure |
| 116 | Annex C (informative) CEM43 C (cumulative equivalent minutes at 43 C) C.1 General C.2 CEM43 for heart and skeletal muscle C.3 CEM43 for the pocket tissue C.3.1 Skin C.3.1.1 Starting temperature |
| 117 | C.3.1.2 Acceptance criteria free from chronic damage |
| 118 | C.3.1.3 Acceptance criteria free from pain C.3.2 Muscle C.3.2.1 Starting temperature C.3.2.2 Acceptance criteria free from chronic damage |
| 119 | C.3.3 Scar material C.4 CEM43 C for the tissue in contact with the lead body C.5 Scan duration |
| 120 | Annex D (informative) In vivo temperature rise in response to applied heat flux D.1 Background D.2 Applicable data D.3 Analysis |
| 121 | D.4 Result |
| 122 | Annex E (normative) Gradient P(UCS) calculation method E.1 General E.2 PDF of Capture Thresholds (Qmin, Rheobase) |
| 123 | E.3 Probability analysis |
| 124 | E.4 Gradient induced charge and current limits (QGRAD_MAX, IGRAD_MAX) |
| 125 | Annex F (normative) RF UCS Compliance criteria F.1 General |
| 126 | F.2 Stress determination F.2.1 Tier 1 F.2.1.1 See 15.5.4 for information on the determination of test conditions and device malfunction. Leverage the RF modelling framework to generate a set of in-human use conditions that define the peak (30 µT) RF levels at the lead electrode RF entry p… F.2.1.2 Determine the 99th percentile RF level at each RF entry points into a device and identify the maximum of the 99th percentile RF levels. Use this maximum 99th percentile RF level as the test level for all lead electrode RF entry points into a d… F.2.1.3 Include phase variation in the testing by applying 0 , 90 , 180 , and 270 phase shift to each RF entry point, one at a time, while injecting RF energy into other RF entry points at 0 . F.2.1.4 See 15.5.2 for information on the RF antenna test to determine the telemetry antenna injection level. Test the lead electrode test level identified in step 2 with the simultaneous antenna injection level determined in step 7 of 15.5.2.1 cycled… F.2.1.5 Perform direct RF-injection test at magnitude and phase condition of each RF entry point. Record the magnitude of rectification pulse for each electrode with respect to case. F.2.1.6 For each electrode, fit the rectification voltage (or current) to an appropriate distribution. Determine the 99th upper tolerance limit with a confidence/reliability of 95/99. F.2.2 Tiers 2 or 3 – Vector generation F.2.2.1 In the case of RF rectification, PDF of stress is essentially the PDF of rectified voltage which can be determined by the steps in F.2.2.2 through F.2.2.7. F.2.2.2 See 15.5.4 for addition information. Leverage the RF modelling framework to generate a set of in-human use conditions that define the peak (30 µT) RF levels at the RF entry points into a device, with RF phase conditions of 15.5.4.5. F.2.2.3 Sort the use conditions from max to min by total power across all RF entry points to generate the PDF of total power. F.2.2.4 Span the test vectors from the region of the PDF of total power between the upper bound of the worst-case power and the lower bound resulting in safe levels of rectification as defined by voltage, current or charge. Unique test cases are deter… F.2.2.5 If phase cycling is used, for each test vector, include that phase variation by applying 0 , 90 , 180 , and 270 phase shift to each RF entry point, one at a time, while injecting RF energy into other RF entry points at 0 . Note that the … F.2.2.6 See 15.5.2 to determine the telemetry antenna injection levels. Test each test vector identified in previous steps with the antenna injection level determined in step 7 of 15.5.2.1 cycled in phase increments and conditions as specified in 15.5… |
| 127 | F.2.2.7 Perform direct RF-injection test at corresponding magnitude and phase condition of each RF entry point. Record the magnitude of rectification pulse for each electrode with respect to case. Typically, the AV and VV delays in MRI mode remove the… F.2.3 Tier 2 – Injection and analysis F.2.3.1 For each test vector, take the maximum rectification differential across any pair of electrodes and plot total power vs. rectified voltage (or current) for all vectors tested (Figure F.3). Fit the maximum rectified voltage (or current) at diff… F.2.3.2 For all power levels less than the minimum tested injection level, assume the rectification is equal to the measured rectification at the minimum injection level. F.2.3.3 Convert the PDF of total power to the PDF of rectified voltage using the relationship defined in F.2.3.1 and F.2.3.2. F.2.4 Tier 3 – Injection and analysis F.2.4.1 For each electrode, plot rectification voltage (or current) vs injected voltage across all vectors tested. Fit the maximum rectified voltage (or current) vs injected voltage to approximate rectified voltage (or current) over entire RF-injectio… F.2.4.2 For all levels less than the minimum tested injection level, assume the rectification is equal to the measured rectification at the minimum injection level. F.2.4.3 Convert the PDF of each electrode to the PDF of rectified voltage using the relationship defined in F.2.4.1 and F.2.4.2. F.3 Strength determination F.3.1 PDF of strength is essentially the PDF of stimulation voltage required to obtain sustained capture. F.3.2 Determine the PDF of stimulation voltage required to obtain sustained capture for electrode(s) evaluated. This information is typically available through clinical data. F.3.3 Calculate the capture stimulation threshold at the measured rectified PW using the strength-duration relationship. If a large transient occurs, the pulse width of the transient shall also be assessed. Specifically, rheobase and chronaxie can be … |
| 128 | F.3.4 Generate the PDF of stimulation voltage using all data points from F.3.2 and F.3.3. As specified in Reilly [49], cardiac stimulation typically follows a lognormal distribution. F.4 Acceptance criteria |
| 129 | Annex G (informative) Example of implementation of MR scan protocols for combined fields G.1 General |
| 130 | G.2 Neurological examinations examples |
| 131 | G.3 Thoracic examinations examples |
| 132 | G.4 Upper limbs examinations examples G.5 Pelvic examinations examples |
| 133 | Bibliography |
