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AAMI/ISO TIR10974:2018 - Assessment of the safety of magnetic resonance imaging for patients with an active implantable medical device., 2018
- AAMI/ISO TIR10974:2018; Assessment of the safety of magnetic resonance imaging for patients with an active implantable medical device
- Title page
- Copyright information
- AAMI Technical Information Report
- ANSI Registration
- Contents Page
- Glossary of equivalent standards
- Committee representation
- Background of the AAMI adoption of ISO TS 10974:2018
- Foreword
- Introduction
- 1 Scope
- 2 Normative references
- 3 Terms and definitions
- 4 Symbols and abbreviated terms
- 5 General requirements for non-implantable parts
- 6 Requirements for particular AIMDs
- 7 General considerations for application of the tests of this document [Go to Page]
- 7.1 Compliance criteria
- 7.2 Use of tiers
- 7.3 Test reports [Go to Page]
- 7.3.1 General
- 7.3.2 Description of the AIMD under test
- 7.3.3 Test methods and results
- 8 Protection from harm to the patient caused by RF-induced heating [Go to Page]
- 8.1 Introduction
- 8.2 Outline of the Stage 1 four-tier approach
- 8.3 Measurement system prerequisites for all tiers [Go to Page]
- 8.3.1 RF field source
- 8.3.2 Tissue simulating phantom
- 8.3.3 Definition of power deposition
- 8.3.4 Measurement system validation
- 8.4 Determination of RF-induced power deposition in a tissue simulating medium [Go to Page]
- 8.4.1 General
- 8.4.2 Determine location of hot spots around the AIMD
- 8.4.3 Determination of spatial (3D) distribution of power deposition for each hot spot [Go to Page]
- 8.4.3.1 General
- 8.4.3.2 Procedure 1: Numerical assessment with thermal validation
- 8.4.3.3 Procedure 2: Numerical assessment with SAR validation
- 8.4.3.4 Procedure 3: Full 3D SAR measurements
- 8.4.3.5 Procedure 4: Full 3D ΔT measurements
- 8.4.4 Determine the final power deposition [Go to Page]
- 8.4.4.1 General
- 8.4.4.2 Procedure 1: Temperature increase ΔT (if using Procedure 4 from 8.4.3)
- 8.4.4.3 Procedure 2: SAR (if using Procedure 1, Procedure 2, or Procedure 3 from 8.4.3)
- 8.4.4.4 Procedure 3: Calibration of point temperature or SAR measurements to total dissipated RF power
- 8.5 Proximity effect of electrodes from multiple leads
- 8.6 Modelling prerequisites for Tier 2, Tier 3, and Tier 4
- 8.7 Tier selection for RF-induced power deposition [Go to Page]
- 8.7.1 General
- 8.7.2 Tier 1
- 8.7.3 Tier 2
- 8.7.4 Tier 3
- 8.7.5 Tier 4
- 8.8 In vitro model validation
- 8.9 Overall uncertainty analysis
- 8.10 In vivo analysis of power deposition
- 8.11 RF-induced heating assessment flow chart
- 9 Protection from harm to the patient caused by gradient-induced device heating [Go to Page]
- 9.1 Introduction
- 9.2 Testing considerations [Go to Page]
- 9.2.1 General
- 9.2.2 Determination of |dB/dt| rms exposure limits
- 9.2.3 Determination of test duration
- 9.3 Test requirements [Go to Page]
- 9.3.1 General
- 9.3.2 In vitro test phantom or other suitable container
- 9.3.3 Gelled solution
- 9.3.4 Temperature survey to determine orientation and hot spots
- 9.3.5 Minimum temperature instrumentation
- 9.3.6 Definition of dB/dt test waveform [Go to Page]
- 9.3.6.1 General
- 9.3.6.2 Tier 1
- 9.3.6.3 Tier 2
- 9.3.7 Characterization of applied dB/dt
- 9.4 Lab testing using simulated MR gradient field
- 9.5 MR scanner testing
- 9.6 Analysis of gradient heating test
- 10 Protection from harm to the patient caused by gradient-induced vibration [Go to Page]
- 10.1 Introduction
- 10.2 Overview of tiers
- 10.3 MR environmental conditions [Go to Page]
- 10.3.1 General
- 10.3.2 Determination of maximum clinical dB/dt
- 10.3.3 Determination of clinical B0
- 10.3.4 Determination of clinical dB/dt × B0
- 10.3.5 Test frequencies [Go to Page]
- 10.3.5.1 General
- 10.3.5.2 Using a clinical MR scan sequence
- 10.3.5.3 Using an arbitrary gradient waveform
- 10.3.6 Test duration
- 10.3.7 Test temperature [Go to Page]
- 10.3.7.1 General
- 10.3.7.2 Room temperature
- 10.3.7.3 Body temperature
- 10.4 General test procedure [Go to Page]
- 10.4.1 Measurement of gradient field and determination of AIMD location
- 10.4.2 AIMD/test unit setup [Go to Page]
- 10.4.2.1 Orientation of AIMD in scanner
- 10.4.2.2 Mounting
- 10.5 Method 1 — MR scanner
- 10.6 Method 2 — Shaker table [Go to Page]
- 10.6.1 General
- 10.6.2 Determine scanner input
- 10.6.3 AIMD vibration response [Go to Page]
- 10.6.3.1 Measurement equipment
- 10.6.3.2 Measure the AIMD vibration response
- 10.6.4 Determine shaker table amplitude (dB/dt scaling)
- 10.6.5 Perform vibration exposure using a shaker table [Go to Page]
- 10.6.5.1 General
- 10.6.5.2 Random vibration
- 10.6.5.3 Profile-driven vibration
- 11 Protection from harm to the patient caused by B0-induced force
- 12 Protection from harm to the patient caused by B0-induced torque
- 13 Protection from harm to the patient caused by gradient-induced extrinsic electric potential [Go to Page]
- 13.1 Introduction
- 13.2 General requirements
- 13.3 Gradient pulse leakage test [Go to Page]
- 13.3.1 General
- 13.3.2 Test equipment
- 13.3.3 Test signal
- 13.3.4 Tier 1 — Combined gradient-induced charge measurement test procedure
- 13.3.5 Tier 2 — Separate transient gradient-induced charge and steady-state current measurement test procedure [Go to Page]
- 13.3.5.1 Gradient-induced charge measurement test procedure
- 13.3.5.2 Gradient-induced current measurement test procedure
- 13.4 Gradient rectification test [Go to Page]
- 13.4.1 General
- 13.4.2 Test equipment
- 13.4.3 Test signal
- 13.4.4 Gradient-induced rectification measurement test procedure
- 13.5 Gradient pulse distortion of AIMD output test [Go to Page]
- 13.5.1 General
- 13.5.2 Test equipment
- 13.5.3 Test signal
- 13.5.4 Gradient-induced AIMD output distortion test procedure
- 14 Protection from harm to the patient caused by B0-induced malfunction [Go to Page]
- 14.1 Introduction
- 14.2 Static field testing [Go to Page]
- 14.2.1 B0 general requirements for static field testing
- 14.2.2 B0 field generation
- 14.2.3 Test conditions
- 14.3 Test procedures [Go to Page]
- 14.3.1 General
- 14.3.2 Class 0 test procedure
- 14.3.3 Class 1 test procedure
- 14.3.4 Class 2 test procedure
- 15 Protection from harm to the patient caused by RF-induced malfunction and RF rectification [Go to Page]
- 15.1 Introduction
- 15.2 General requirements
- 15.3 Mechanisms for RF interaction with an AIMD
- 15.4 Selecting radiated vs injected test methods [Go to Page]
- 15.4.1 General
- 15.4.2 AIMD type designation for test method selection
- 15.4.3 RF antenna type designation for test method selection
- 15.4.4 RF EMC tier selection
- 15.4.5 RF test conditions
- 15.4.6 B0 considerations
- 15.5 Injected immunity test [Go to Page]
- 15.5.1 General
- 15.5.2 Determination of peak and rms injected levels for Tier 1 and Tier 2 — AIMD with short electrical length
- 15.5.3 Determination of peak and rms injected levels for Tier 3 and Tier 4
- 15.5.4 Injected immunity test procedure
- 15.5.5 RF phase test conditions
- 15.5.6 AIMD monitoring during the test
- 15.6 Radiated immunity test [Go to Page]
- 15.6.1 General
- 15.6.2 Determining the RF radiated field level
- 15.6.3 Radiated test procedure
- 15.6.4 AIMD monitoring during the test
- 15.7 Test equipment [Go to Page]
- 15.7.1 Generating the RF electric field for radiated testing (AIMD with short electrical length)
- 15.7.2 Phantom and tissue simulating medium for radiated testing
- 15.7.3 AIMD monitoring apparatus
- 15.7.4 RF level measuring device
- 15.7.5 RF injection network
- 15.8 Determining the peak RF injected level using a radiated test
- 16 Protection from harm to the patient caused by gradient-induced malfunction [Go to Page]
- 16.1 Introduction
- 16.2 General requirements
- 16.3 Selecting radiated and injected test methods
- 16.4 Radiated immunity test [Go to Page]
- 16.4.1 General
- 16.4.2 Test equipment
- 16.4.3 Radiated test signal
- 16.4.4 Test procedure
- 16.5 Injected immunity test [Go to Page]
- 16.5.1 General
- 16.5.2 Test equipment
- 16.5.3 Injected test signal
- 16.5.4 Test procedure
- 16.5.5 AIMD test configuration [Go to Page]
- 16.5.5.1 General
- 16.5.5.2 Group a)
- 16.5.5.3 Group b)
- 16.5.5.4 Tissue interface network
- 17 Combined fields test [Go to Page]
- 17.1 Introduction
- 17.2 Test setup
- 17.3 AIMD fixation
- 17.4 Test procedure [Go to Page]
- 17.4.1 General
- 17.4.2 Before MR exposure
- 17.4.3 During MR exposure
- 17.4.4 After MR exposure
- 17.5 Test equipment [Go to Page]
- 17.5.1 Field generation
- 17.5.2 Phantom and tissue simulating medium
- 17.5.3 AIMD monitoring apparatus
- 18 Markings and accompanying documentation [Go to Page]
- 18.1 Definitions
- 18.2 Applicability of labelling requirements
- 18.3 Labelling requirements
- Annex A (normative) Pulsed gradient exposure for Clause 10, Clause 13, and Clause 16 [Go to Page]
- A.1 Pulsed gradient exposure for Clauses 10, 13, and 16
- A.2 Determination of dB/dt for AIMD electronics module, electrodes, and extended leads [Go to Page]
- A.2.1 AIMD labelled for Fixed Parameter Option
- A.2.2 AIMD labelled for maximum gradient slew rate
- A.3 Injected voltage determination [Go to Page]
- A.3.1 General
- A.3.2 Tier 1, Lead length multiplication factor method
- A.3.3 Tier 2, Specific AIMD lead loop area method
- A.3.4 Tier 3, Electromagnetic simulation method
- A.3.5 Model validation for Tier 3
- Annex B (informative) Derivation of lead length factor for injected voltage test levels for Clause 13 and Clause 16
- Annex C (informative) Tier 1 high tangential E-field trough line resonator [Go to Page]
- C.1 Background
- C.2 Design Example
- C.3 Performance
- Annex D (informative) Supporting information and rationale for gradient-induced device heating [Go to Page]
- D.1 Rationale for gradient heating |dB/dt| rms [Go to Page]
- D.1.1 General
- D.1.2 Data survey of clinical MR scanners
- D.1.3 Determination of clinical dB/dt exposure limits
- D.2 Gradient heating Tier 1 waveform rationale [Go to Page]
- D.2.1 General
- D.2.2 Waveform type
- D.2.3 Magnitude of |dB/dt| rms
- D.2.4 Magnitude of BG
- D.2.5 Waveform frequency
- Annex E (informative) Example RF injection network
- Annex F (informative) Supporting information and rationale for MR-induced vibration [Go to Page]
- F.1 Explanation of MR-induced vibration
- F.2 Tiers: MR scanner vs shaker table
- F.3 Clinical scanner vs research scanner
- F.4 Potential for AIMD resonance
- F.5 Supporting rationales [Go to Page]
- F.5.1 Gradient switch mode noise (“Ripple”)
- F.5.2 Discussion of location for max dB/dt × B0
- F.5.3 Rationale for test frequencies
- F.5.4 Rationale for scan duration
- F.5.5 Rationale for test temperature
- F.6 Vibration measurement equipment consideration
- Annex G (informative) Gradient vibration patent declaration form
- Annex H (informative) Assessment of dielectric and thermal parameters [Go to Page]
- H.1 Introduction [Go to Page]
- H.1.1 General
- H.1.2 HPM Considerations
- H.1.3 LPM Considerations
- H.2 Dielectric parameters [Go to Page]
- H.2.1 General
- H.2.2 Method 1
- H.2.3 Method 2
- H.2.4 Method 3
- H.2.5 Good measurement practices to achieve precise dielectric measurements [Go to Page]
- H.2.5.1 General
- H.2.5.2 Method 1 (open coaxial probe)
- H.2.5.3 Method 2 (slotted line)
- H.2.5.4 Method 3 (static conductivity meter)
- H.3 Thermal parameters [Go to Page]
- H.3.1 General considerations
- H.3.2 Methods [Go to Page]
- H.3.2.1 Introduction
- H.3.2.2 Method to determine heat capacity
- H.3.2.3 Method to determine thermal conductivity
- Annex I (informative) RF exposure system validation method [Go to Page]
- I.1 Objective
- I.2 Validation procedure
- I.3 Standard test object definitions
- I.4 Example SAIMD exposure simulation target values [Go to Page]
- I.4.1 General
- I.4.2 Example SAIMD-1 target values
- I.4.3 Example SAIMD-2 target values
- I.5 Test object measurement
- I.6 Compare simulation target values to measured results
- Annex J (informative) MR scanner RF transmit coil
- Annex K (informative) Current distribution on the AIMD as a function of the phase distribution of the incident field [Go to Page]
- K.1 Background
- K.2 Phase gradients in lossy dielectrics
- K.3 Transfer function to determine induced heating
- Annex L (informative) Tissue simulating medium formulations
- L.1 Rationale
- L.2 HPM and LPM Recipes
- L.3 Example preparation methods [Go to Page]
- L.3.1 General
- L.3.2 LPM formulation
- L.3.3 PAA HPM formulation
- Annex M (informative) Generation of incident fields [Go to Page]
- M.1 General
- M.2 Background
- M.3 Uniform incident field distributions
- M.4 Non-uniform incident field distributions
- M.5 Pathway modifications
- Annex N (informative) Dielectric and thermal tissue properties
- Annex O (informative) Gradient field injected testing — AIMD electrode tissue impedance determination method [Go to Page]
- O.1 Background
- O.2 Theory
- O.3 Test setup
- O.4 Tissue interface network implementation
- Annex P (informative) Estimation of conservative B1 and 10 g averaged E-field values for Tier 1 for RF-induced heating and RF malfunction [Go to Page]
- P.1 Objective
- P.2 Methods
- P.3 Results
- P.4 Scaling of results for Tier 1 of RF-induced malfunction
- Annex Q (informative) AIMD configuration
- Annex R (informative) Electrically excitable tissue stimulation, terms and definitions [Go to Page]
- R.1 General
- R.2 Stimulation Assessment [Go to Page]
- R.2.1 General
- R.2.2 Charge duration curve comparison
- R.2.3 Strength duration curve comparison
- Annex S (informative) Combined fields test [Go to Page]
- S.1 Example of MR protocol implementation [Go to Page]
- S.1.1 General
- S.1.2 Neurological examinations examples
- S.1.3 Thoracic examinations examples
- S.1.4 Upper limbs examinations examples
- S.1.5 Pelvic examinations examples
- S.1.6 Lower limb examination examples
- S.2 Example of system test configuration
- Annex T (informative) General methods for modelling dB/dt levels in MR gradient coils [Go to Page]
- T.1 General
- T.2 Gradient design methods [Go to Page]
- T.2.1 Method of designing single coil
- T.2.2 Method of designing different coil axes
- T.2.3 Method of designing a set of three gradient axes
- T.2.4 Methods of designing the family of 60-cm bore coil designs
- T.2.5 Methods of designing the family of 70-cm bore coil designs
- T.3 Gradient field calculation methods [Go to Page]
- T.3.1 General method for calculating magnetic fields within coils
- T.3.2 Region for general magnetic field calculations within coils
- T.4 dB/dt calculation methods [Go to Page]
- T.4.1 Derivation of dB/dt
- T.4.2 Specifics regarding generation of dB/dt table
- Bibliography [Go to Page]