ISO/TS 10974:2012

TECHNICAL ISO/TS
SPECIFICATION 10974
First edition
2012-05-01

Assessment of the safety of magnetic
resonance imaging for patients with an
active implantable medical device
Évaluation de la sécurité de l'imagerie par résonance magnétique pour
les patients avec un dispositif médical implantable actif




Reference number
ISO/TS 10974:2012(E)
©
ISO 2012

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ISO/TS 10974:2012(E)

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ii © ISO 2012 – All rights reserved

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ISO/TS 10974:2012(E)
Contents Page
Foreword . vii
Introduction . viii
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 2
4  Symbols and abbreviated terms . 7
5  General requirements for non-implantable parts . 7
6  Requirements for particular AIMDs . 7
7  Protection of patients from potential hazards caused by interactions of the AIMD and MR
scanners . 8
8  Test signals . 9
8.1  Gradient sequence of sequences . 9
8.2  RF sequence of sequences . 11
9  General considerations for application of the requirements of this Technical Specification . 14
9.1  Compliance criteria . 14
9.2  Monitoring equipment . 14
9.3  Validation of models and test equipment . 14
9.4  Uncertainty assessment . 14
9.5  Test reports . 14
10  Protection from harm to the patient caused by RF-induced heating . 15
10.1  General . 15
10.2  Outline of the four-tier approach . 16
10.2.1  Tier 1 . 16
10.2.2  Tier 2 . 18
10.2.3  Tier 3 . 18
10.2.4  Tier 4 . 19
10.3  Determination of the induced electric and magnetic fields . 20
10.3.1  Electromagnetic simulation . 20
10.3.2  Relevant parameters . 20
10.3.3  Assessment procedure . 20
10.3.4  Uncertainty budget of incident field assessment . 20
10.4  Validation of electromagnetic AIMD models . 21
10.4.1  Validation procedure . 21
10.4.2  Validation criteria . 21
10.5  Generation of incident fields for Tier 1 to Tier 3 and minimal medium requirements . 21
10.6  Measurement system requirements . 22
10.6.1  Probe specification . 22
10.6.2  Validation and characterization of the measurement system . 22
10.7  Procedures and protocols for determination of the distribution and magnitude of the
absorbed energy in the tissue equivalent material by SAR and T measurements . 23
10.7.1  Determination of 3D relative distribution of local energy deposition . 23
10.7.2  Measurement protocol for determination of maximum amplitude . 24
10.8  Uncertainty assessment of energy deposition using SAR or temperature probes . 27
10.9  Compliance criteria . 28
10.10  Test report . 28
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ISO/TS 10974:2012(E)
11  Protection from harm to the patient caused by gradient-induced device heating . 28
11.1  General . 28
11.2  Testing considerations. 29
11.2.1  General . 29
11.2.2  Determination of clinical dB/dt exposure limits . 29
11.2.3  Test duration . 30
11.2.4  Data collection . 30
11.3  Test requirements . 31
11.3.1  General . 31
11.3.2  In vitro, phantom or other suitable container . 31
11.3.3  Gelled solution . 31
11.3.4  Optical temperature probes . 31
11.3.5  Temperature survey to determine worst-case orientation and hot spots . 32
11.3.6  Minimum temperature instrumentation . 32
11.3.7  Temperature data collection . 32
11.3.8  Monitor applied dB/dt . 32
11.3.9  Gradient field vector orientation relative to device . 32
11.3.10 Monitoring AIMD for heating and malfunction . 32
11.4  Lab testing using simulated MRI gradient field . 33
11.4.1  Simulated field requirements . 33
11.4.2  Pulse waveform RMS value . 33
11.4.3  Gradient sequence of sequences . 33
11.5  MR scanner testing . 33
11.6  Analysis of gradient heating test . 34
11.7  Uncertainty assessment . 34
11.8  Test report . 34
12  Protection from harm to the patient caused by gradient-induced vibration . 35
12.1  General . 35
12.2  General test considerations . 36
12.2.1  Equipment . 36
12.2.2  Determination of clinical dB/dt and B exposure limits . 39
0
12.2.3  Test signals . 39
12.3  Test method for the evaluation of AIMD functionality during exposure to gradient-induced
vibration . 39
12.3.1  General requirements . 39
12.3.2  Conducting functional testing using a research scanner . 40
12.3.3  Conducting functional testing using simulated fields . 40
12.3.4  Conducting functional testing using a clinical scanner . 40
12.3.5  Conducting functional testing using a shaker table or other vibration test equipment . 40
12.4  Test method for the evaluation of patient discomfort during exposure to gradient-induced
vibration . 41
12.4.1  General requirements . 41
12.4.2  Conducting patient discomfort testing using a research scanner . 42
12.4.3  Conducting patient discomfort testing using simulated fields. 42
12.4.4  Conducting patient discomfort testing using a clinical scanner . 42
12.4.5  Conducting patient discomfort testing using a shaker table or other vibration test
equipment . 43
12.5  Test method for the evaluation of risk of tissue injury during exposure to gradient-
induced vibration . 43
12.5.1  General requirements . 43
12.5.2  Conducting testing for the evaluation of risk of tissue injury using a research scanner . 46
12.5.3  Conducting testing for the evaluation of risk of tissue injury using simulated fields . 46
12.5.4  Conducting testing for the evaluation of risk of tissue injury using a clinical scanner . 46
12.5.5  Conducting testing for the evaluation of risk of tissue injury using a shaker table or other
vibration test equipment . 46
12.6  Uncertainty assessment . 47
12.7  Test report . 47
13  Protection from harm to the patient caused by B -induced force . 47
0
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ISO/TS 10974:2012(E)
14  Protection from harm to the patient caused by B -induced torque . 47
0
15  Protection from harm to the patient caused by image artefact . 48
16  Protection from harm to the patient caused by gradient-induced extrinsic electric
potential . 48
16.1  General . 48
16.2  Test procedure . 48
16.3  Uncertainty assessment . 49
16.4  Test report . 49
17  Protection from harm to the patient caused by RF rectification . 49
17.1  General . 49
17.2  Test procedure . 49
17.3  Uncertainty assessment . 50
17.4  Test report . 50
18  Protection from harm to the patient caused by B -induced malfunction . 50
0
18.1  General . 50
18.2  Test procedure . 50
18.3  Test equipment . 50
18.3.1  Generating the B field . 50
0
18.3.2  Phantom and tissue simulation medium . 51
18.4  Uncertainty assessment . 51
18.5  Test report . 51
19  Protection from harm to the patient caused by RF-induced malfunction . 51
19.1  Introduction of tiered approach . 51
19.2  Injected immunity test . 53
19.2.1  Using the tiers . 53
19.2.2  Test procedure . 55
19.2.3  Test equipment . 55
19.2.4  Uncertainty assessment . 55
19.2.5  Test report . 55
19.3  Radiated immunity test . 56
19.3.1  Using the tiers . 56
19.3.2  Test procedure . 56
19.3.3  Test equipment . 56
19.3.4  Uncertainty assessment . 57
19.4  Test report . 57
20  Protection from harm to the patient caused by gradient-induced malfunction . 57
20.1  Introduction of tiered approach . 57
20.2  Injected immunity test . 58
20.2.1  Tier 1 . 58
20.2.2  Tier 2 . 62
20.2.3  Tier 3 . 65
20.2.4  Test procedure . 67
20.2.5  Test equipment . 67
20.2.6  Uncertainty assessment . 67
20.2.7  Test report . 67
20.3  Radiated immunity test . 67
20.3.1  Applicability . 67
20.3.2  Tier 1 . 67
20.3.3  Tier 2 . 68
20.3.4  Test procedure . 69
20.3.5  Test equipment . 69
20.3.6  Uncertainty assessment . 69
20.3.7  Test report . 69
21  Combined fields test . 69
22  Markings and accompanying documentation . 70
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ISO/TS 10974:2012(E)
Annex A (informative) Gradient vibration patent declaration form . 72
Annex B (informative) Derivation of lead length factor for injected voltage test levels for gradient-
induced malfunction . 74
Annex C (informative) Basic MR physics . 78
Annex D (informative) Gradient injection network . 80
Annex E (informative) RF injection network . 82
Annex F (informative) Estimation of the temperature rise in vivo from determined energy
deposition . 85
Annex G (informative) Methods of assessment of the temperature rise in vivo . 88
Annex H (informative) Assessment of dielectric and thermal parameters . 91
Annex I (normative) Measurement system validation . 94
Annex J (informative) Example of coil systems . 107
Annex K (informative) Current distribution on the AIMD as a function of the phase distribution of
the incident field . 108
Annex L (informative) Recipe and rationale for tissue simulating materials . 111
Annex M (informative) Generation of incident fields . 113
Annex N (informative) Dielectric parameters. 117
Annex O (informative) Thermal and electrical properties of scar tissues . 119
Annex P (informative) Estimation of conservative B and 10g averaged E-field values for Tier 1 for
1
RF-induced heating and malfunction . 120
Annex Q (informative) AIMD configurations . 126
Annex R (normative) Uncertainty evaluation . 127
Annex S (informative) Guidance on gradient field interactions and test methods for pacemakers. 145
Annex T (informative) Characterization of lead port interface impedance for evaluating gradient-
induced extrinsic electric potential effects . 169
Annex U (informative) Method for in vitro measurement of gradient-induced E-field . 173
Annex V (informative) Basic physics and interactions of gradient magnetic fields with AIMDs . 184
Bibliography . 197

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ISO/TS 10974:2012(E)
Foreword
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An ISO/PAS or ISO/TS
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