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Cited by 180Atomic and Subatomic Physics ResearchMagnetic Field Sensors TechniquesGeomagnetism and Paleomagnetism Studies

Biomagnetism using SQUIDs: status and perspectives

Open access
Sternickel, Karsten, Braginski, Alex I·2006·Superconductor Science and Technology
DOI 10.1088/0953-2048/19/3/024
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Abstract

Biomagnetism involves the measurement and analysis of very weak local magnetic fields of living organisms and various organs in humans. Such fields can be of physiological origin or due to magnetic impurities or markers. This paper reviews existing and prospective applications of biomagnetism in clinical research and medical diagnostics. Currently, such applications require sensitive magnetic SQUID sensors and amplifiers. The practicality of biomagnetic methods depends especially on techniques for suppressing the dominant environmental electromagnetic noise, and on suitable nearly real-time data processing and interpretation methods. Of the many biomagnetic methods and applications, only the functional studies of the human brain (magnetoencephalography) and liver susceptometry are in clinical use, while functional diagnostics of the human heart (magnetocardiography) approaches the threshold of clinical acceptance. Particularly promising for the future is the ongoing research into low-field magnetic resonance anatomical imaging using SQUIDs.

Integrity signals

Registry

Crossref · 10.1088/0953-2048/19/3/024

Cites

44 of 44 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

3 of 42 cited sources checked · 1 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Mapping of internal current sources from externally measured magnetic fields is attempted by solving the forward or inverse problem.

    “Mapping of internal current sources from externally measured magnetic fields is attempted by solving the forward or inverse problem [7,17].”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [7] Vrba J, 2002, Supercond. Sci. Technol. source
    • cites [17] Vrba J, 2006, SQUID Handbook

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Premisecitation

    Various variants of the minimum norm technique are usually employed to obtain an approximate solution of the inverse problem.

    “To obtain an approximate solution of the inverse problem, various variants of the minimum norm technique are usually employed [7,16,19].”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites [7] Vrba J, 2002, Supercond. Sci. Technol. source

      Section 3.1 describes localizing a dipole by fitting measured fields to a forward model, and the Number of channels section describes least-squares dipole fitting. Neither passage says that variants of the minimum-norm technique are usually used to approximate solutions to the inverse problem. Searches for minimum-norm inverse solutions found no passage addressing that claim. (LLM, conf=0.72)

      Experimental — accuracy not yet measured
    • cites [16] source
    • cites [19] Sachse F B Werner C D Stenroos M H Schulte R F Zerfass P Dössel O, 2000, Proc. 3rd Users Conf. of the National Library of Medicine’s Visible Human Project

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Findingcitation

    MCG can detect repolarization abnormalities (potential heart infarction) at rest even in patients with non-specific 12-lead ECG and normal troponine enzyme test.

    “As another, the ability to detect repolarization abnormalities (potential heart infarction) at rest, even in patients with non-specific 12-lead ECG and normal troponine enzyme test [28].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [28] source

      The Data Analysis section describes MCG findings during the T-wave repolarization interval as criteria for ischemia. The Discussion reports that admission MCG predicted coronary artery disease despite false-negative ECG and troponin-I findings, including in patients whose ECG was nondiagnostic. The study assessed ischemia and coronary artery disease, however, not MCG detection of a potential myocardial infarction; its Methods say patients with an unambiguously ECG-diagnosed acute infarction were excluded. Page numbers are unavailable in our copy. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Findingcitation

    Systems suitable for foetal MEG are used in clinical research.

    “Even systems suitable for foetal MEG are used in clinical research [16,26].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [16] source
    • cites [26] Okada Y, 2006, Rev. Sci. Instrum. source
  • Findingcitation

    High-Tc SQUIDs are less sensitive, especially at low frequencies below about 10 Hz due to their high 1/f noise.

    “High-T c SQUIDs are less sensitive, especially at low frequencies below, say, 10 Hz due to their high 1/ f noise [2,3].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [2] Clarke J, 2004, SQUID Handbook source
    • cites [3] Clarke J, 2006, SQUID Handbook source
  • Classified as probably not a substantial claim. 71
  • May combine two claims. 37
  • The quote only partly states this claim. 1

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Findingnone given

    Of the many biomagnetic methods and applications, only functional studies of the human brain (MEG) and liver susceptometry are in clinical use, while functional diagnostics of the human heart (MCG) approaches the threshold of clinical acceptance.

    “Of the many biomagnetic methods and applications, only the functional studies of the human brain (magnetoencephalography) and liver susceptometry are in clinical use, while functional diagnostics of the human heart (magnetocardiography) approaches the threshold of clinical acceptance.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    MEG mapping and localization results are as a rule superposed with anatomical images obtained usually by MRI.

    “The results of such mapping and localization are as a rule superposed (fused) with anatomical images obtained usually by MRI.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Non-adaptive filters, including notch filters, generally distort the signal somewhat.

    “The use of non-adaptive filters, however, is not without risk: notch filters, also used to suppress the power line frequencies, generally distort the signal somewhat.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Findingnone given

    Well-balanced first-order hardware gradiometers suppress common-mode noise typically by a factor of 10^2-10^4, with electronic reference corrections up to 10^6.

    “Well-balanced first-order hardware gradiometers suppress common-mode (spatially homogeneous) noise typically by a factor of 10 2 -10 4 , with electronic reference corrections up to 10 6 .”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Modern commercial MEG systems are whole-cortex SQUID arrays measuring locally the radial magnetic field components of the brain.

    “Modern commercial MEG systems are, as a rule, wholecortex SQUID arrays measuring locally the radial magnetic field components of the brain.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Documented uses of MEG are quite broad and expanding, including language studies, psychopharmacology and neuropsychiatry.

    “While we give only these two examples, we emphasize that documented uses of MEG are quite broad and expanding, also in language studies, psychopharmacology and neuropsychiatry (mental health studies).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Findingnone given

    The typical number of MEG sensors ranges between about 120 and 300, and tends to be higher in the newest models.

    “The typical number of sensors ranges between about 120 and 300, and tends to be higher in the newest models.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    High-Tc SQUIDs have B_N between 10 and 100 fT Hz -1/2.

    “High-T c SQUIDs, having B N in the range between 10 and 100 fT Hz -1/2 might be usable in some applications.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    In most neurological and psychological studies, brain responses intentionally evoked by various external somatosensory stimuli are measured.

    “In most neurological and psychological studies, brain responses intentionally evoked by various external somatosensory stimuli (auditory, visual, tactile, olfactory) are measured.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Distortion increases with the gradiometer order.

    “Distortion shall increase with the gradiometer order.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Induced signals of impurities and markers can be stronger, up into the nanotesla range.

    “Induced signals of impurities and markers can be stronger, up into the nanotesla range.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Findingnone given

    In the USA, MEG preoperative use is approved by the FDA and reimbursed by a number of insurance companies.

    “In the USA, the MEG preoperative use is approved by the Food & Drug Administration (FDA) and reimbursed by a number of insurance companies.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Most MEG systems are universal, permitting measurements in both seated and supine positions.

    “Most systems are universal, permitting measurements in both positions.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    At present, approximately 120 MEG systems are operational or in installation worldwide.

    “At present, approximately 120 MEG systems are operational or in installation worldwide.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    The MEG systems mentioned are suitable for adult subjects and patients.

    “The systems mentioned above are suitable for adult subjects and patients.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Measurable biomagnetic signals generated by living tissues range from about 1 fT (nerves) to 100 pT (human heart) Hz -1/2.

    “In terms of the magnetic field (induction) spectral intensity, B, measurable signals generated by living tissues range from about 1 fT (nerves) to 100 pT (human heart) Hz -1/2 .”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    MEG is already broadly accepted in advanced neurological and psychological research as a functional mapping tool complementary and superior to EEG.

    “This method is already broadly accepted in advanced neurological and psychological research, as a functional mapping tool complementary and superior to EEG.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    Viable technical solutions for mechanical cryocoolers exist and their implementation into biomagnetic hardware is budding in smaller systems.

    “This still poses technical challenges for the near future, but viable technical solutions exist, and their implementation into biomagnetic hardware is now budding in smaller systems [4].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [4] Weinstock H, 1995, SQUID Sensors: Fundamentals, Fabrication and Applications source

  • May combine two claims.

    Findingcitation

    Effects as subtle as migraine centres can be localized in the cortex, and their evolution in time during a migraine attack followed.

    “To give just one more example, effects as subtle as migraine centres can be localized in the cortex, and their evolution in time during a migraine attack followed [23].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [23] source

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Findingnone given

    Current low-Tc SQUID technology satisfactorily fulfils requirements for signal sensitivity, dynamic range and slew rate, and further modest improvements are possible.

    “Current low-T c SQUID technology fulfils these requirements satisfactorily and further modest improvements are possible.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    Cultural electromagnetic noise can have intensities exceeding those to be measured by up to twelve orders of magnitude and sometimes comparable to the Earth's magnetic field.

    “The latter can have intensities exceeding those to be measured by up to twelve orders of magnitude (in the worst cases), and sometimes attaining levels comparable to that of the Earth's magnetic field.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Low-Tc SQUID intrinsic noise floor B_N is typically between 1 and 10 fT Hz -1/2.

    “The liquid-heliumcooled, low-T c SQUID intrinsic noise floor or magnetic field resolution, B N , is typically in the range between 1 and 10 fT Hz -1/2 .”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    The intrinsic sensitivity of MEG sensors, B_N, is typically a few fT/Hz^1/2.

    “The intrinsic sensitivity of sensors, B N , is typically a few fT/Hz 1/2 .”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingnone given

    MEG acceptance is increasing in clinical practice, where it is used mostly for preoperative functional mapping and localization, especially of epileptic foci.

    “Acceptance is also increasing in clinical practice, where it is used mostly for preoperative functional mapping and localization, especially of epileptic foci.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    babySQUID has 76 gradiometric channels with B_N <10 fT/Hz^1/2 plus an 8-channel tensor reference array and is capable of operating in an unshielded environment.

    “It has 76 gradiometric channels with B N < 10 fT/Hz 1/2 plus an 8-channel tensor reference array and is capable of operating in an unshielded environment.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [25] source

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    As a rule, a large number of EEG channels, for example 128, is included for simultaneous MEG and EEG data acquisition.

    “As a rule, a large number of EEG channels (e.g., 128) is also included for simultaneous MEG and EEG data acquisition.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Measurable MEG signals are those of cortical columns representing collective action of 10^4-10^5 neuronal dendritic cells.

    “Generally, measurable signals are those of cortical columns representing collective action of 10 4 -10 5 neuronal dendritic cells.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Findingnone given

    Well over 90% of all operating SQUIDs worldwide are used in medical research and diagnostics, mostly of the human brain.

    “Today, well over 90% of all operating SQUIDs worldwide are used in medical research and diagnostics, mostly of the human brain.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    MEG is currently the dominant area of biomagnetism.

    “The scope of this article does not permit us to cover the many areas of MEG application, but we acknowledge that MEG is currently the dominant area of biomagnetism.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Research users usually require shielding for the best possible results.

    “Nevertheless, research users usually require shielding for the best possible results.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Currently, the typical signal representation for diagnostic MCG use is the 2D map of instantaneous magnetic field intensity B_z and its time evolution during the whole cardiac cycle or a sub-segment of it.

    “Currently, the typical signal representation for diagnostic use is the 2D map of instantaneous magnetic field intensity, B z , and its time evolution during the whole cardiac cycle or a sub-segment of it.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Temporal MCG traces are largely analogous to ECG traces.

    “The temporal MCG traces are largely analogous to ECG traces.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    When the magnetic field can be represented by one equivalent magnetic or current dipole, its time evolution and deviations from normal pattern are usually quantified for disease characterization and classification.

    “In cases where the magnetic field can be represented by one equivalent magnetic or current dipole (EMD, ECD), its time evolution and deviations from normal (healthy) pattern are usually quantified for disease characterization and classification.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    The significance of electrically silent local heart sources for disease diagnostics is currently being explored.

    “The significance of such sources for disease diagnostics is currently being explored.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    The practicality of biomagnetic methods depends especially on techniques for suppressing dominant environmental electromagnetic noise and on suitable nearly real-time data processing and interpretation methods.

    “The practicality of biomagnetic methods depends especially on techniques for suppressing the dominant environmental electromagnetic noise, and on suitable nearly real-time data processing and interpretation methods.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Currently, biomagnetic applications require sensitive magnetic SQUID sensors and amplifiers.

    “Currently, such applications require sensitive magnetic SQUID sensors and amplifiers.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Signal averaging can effectively reduce uncorrelated noise and is suitable for periodical or readily repeatable biosignals rather than single or aperiodic events.

    “Signal averaging can effectively reduce uncorrelated noise.It is suitable when measuring periodical or readily repeatable biosignals, rather than single or aperiodic events.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    The three main categories of remedies for environmental noise are passive and active shielding, magnetic gradiometry, and signal filtering, averaging and mathematical separation methods.

    “The three main categories of remedies are: (i) passive and active magnetic and electromagnetic shielding, (ii) magnetic gradiometry, and (iii) signal filtering, averaging and more sophisticated mathematical methods of separating signals originating from sources at different locations.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Knowledge of the location and nature of biomagnetic sources is key to diagnostically relevant information.

    “Knowledge of the location and nature of biomagnetic sources is the key to diagnostically relevant information.”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Interpretationreasoning

    Measured composite biosignals simultaneously originating from sources at various positions with respect to the sensing coil may be distorted by gradiometers.

    “Therefore, measured composite biosignals simultaneously originating from sources at various positions with respect to the sensing coil may be distorted.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Electric and magnetic fields of physiological sources are orthogonal in space, and in some cases they can be measured simultaneously to acquire complementary information.

    “Electric and magnetic fields of physiological sources are orthogonal in space, and in some cases they can be measured simultaneously to acquire complementary information.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    To arrive at a unique solution of the inverse problem, one should assume a realistic but simplified mathematical model of the source and use information from other functional and anatomical measurements.

    “To arrive at a unique solution, one should assume a possibly realistic, but simplified mathematical model of the source(s) [17,18], and use the information obtained from other measurements, both functional and anatomical.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [17] Vrba J, 2006, SQUID Handbook

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [18] Dössel O, 2000

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    The slow penetration of MEG into hospital routine use is mainly due to the high investment cost of the whole system and special siting requirements for any shielded room.

    “Its rather slow penetration into hospital routine use is mainly due to the high investment cost (of the whole system) and special siting requirements for any shielded room.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisereasoning

    Maxwell's equations imply that when there are bioelectric fields there are also biomagnetic fields, and vice versa.

    “Maxwell's equations tie time-varying electric and magnetic fields together so that when there are bioelectric fields there are also bioelectromagnetic fields, and vice versa.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    Multichannel SQUID arrays are suitable for functional magnetic imaging or mapping of selected organs and may also be useful for anatomical imaging by low-field MRI.

    “Multichannel SQUID arrays for simultaneous measurement at many locations are suitable for functional magnetic imaging or mapping of selected organs and may also be useful for anatomical imaging by low-field MRI (LFMRI).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Localization algorithms acting like spatial filters perform forward calculations and simultaneously separate noise sources.

    “Localization algorithms acting like spatial filters (e.g., the beamformers) perform forward calculations.Such spatial filters simultaneously separate noise sources, as mentioned above.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationnone given

    The equivalent current dipole model is often adequate for brain modelling but may be inadequate for the diseased heart.

    “As an example, the simplest possible model is the equivalent current dipole (ECD).It is often adequate for brain modelling, but may be inadequate, e.g., for the diseased heart.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    High-Tc SQUIDs might be used in applications such as heart diagnostics.

    “Such SQUIDs might be used in applications such as heart diagnostics.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    MUSIC and beamformers are typically used for local, point-like stationary sources and as forward solutions for source localizations.

    “The latter two are typically used for local, point-like stationary sources, e.g. in the human brain, and are also used as forward solutions for source localizations (see section 4 below).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Noise gradients shall not be subtracted.

    “However, noise gradients shall not be subtracted.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationnone given

    The best and ultimate verification of a model and localization algorithm's effectiveness is experimental verification using invasive methods.

    “The best and ultimate verification of a given model and localization algorithm's effectiveness is an experimental verification using invasive methods, by introducing sensing and stimulating electrodes.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Electric and magnetic fields emanated by living matter usually have a common physiological origin.

    “Electric and magnetic fields emanated by living matter usually have a common physiological origin.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    All gradiometers are spatial filters that preferentially select nearest signal sources.

    “All gradiometers are spatial filters, which preferentially select nearest signal sources.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    Not all functions of organs can be properly interpreted by localized solutions, for example higher-order cognitive functions of the brain such as language or memory.

    “We note that not all functions of organs can be properly interpreted by localized solutions.This is the case, for example, of higher-order cognitive functions of the brain such as language or memory.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    Local magnetic shielding as introduced in [5] is a potential solution to the MSR dilemma.

    “A potential solution to the dilemma could be the usage of local magnetic shielding as introduced, for example, in [5].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] Fagaly R, 2005

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Interpretationnone given

    MCG's eventual broad acceptance in medical practice is likely, but only after publication of many high quality clinical trials in representative medical journals.

    “Its eventual broad acceptance in medical practice is likely, but only after publication of many high quality clinical trials occurs in representative medical journals.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Liver susceptometry does not involve imaging, but rather an integral quantitative assessment of iron stores in the liver.

    “Liver susceptometry does not involve imaging, but rather an integral quantitative assessment of iron stores in the liver [1,16].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [1] Andrä W, 1998, Magnetism in Medicine

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [16] source

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    Broad clinical acceptance of MCG, if it occurs, should have a positive effect on the clinical introduction of other methods such as MNG, MGG and MENG, because hardware with planar sensor arrays is also usable for them.

    “Broad clinical acceptance of MCG, if it occurs, should have a positive effect on the clinical introduction of other methods, such as MNG, MGG and MENG (table 1), because hardware with planar sensor arrays is also usable here.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    MEG and liver susceptometry hardware is relatively mature and only incremental improvements should be expected, except for eventual MEG integration with LFMRI.

    “The MEG and liver susceptometry hardware is relatively mature and only incremental improvements should be expected, except for eventual MEG's integration with LFMRI.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    The probability is high that LFMRI will soon become a new major direction of commercial developments and practical implementation.

    “While the LFMRI is still in the research phase, the probability is high that it will soon become a new major direction of commercial developments and practical implementation.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Few commercial MCG systems exist, in both magnetically shielded and unshielded variants, and most should be considered prototypes.

    “Few commercial MCG systems exist (see figure 9), in both magnetically shielded and unshielded variants, most of which should be considered prototypes.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based). May combine two claims.

    Interpretationnone given

    Biomagnetism using SQUID offers a wide spectrum of clinical research and diagnostic opportunities, of which at least some should eventually have a major impact on health care quality and economics.

    “It offers a wide spectrum of clinical research and diagnostic opportunities, of which at least some should eventually have a major impact on health care quality and economics.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    If broadly accepted, MCG might have the highest socio-economical impact of all biomagnetic methods, because it offers a completely non-invasive and fast test for major heart diseases and risks, including heart infarction.

    “Nevertheless, if broadly accepted, MCG might have the highest socio-economical impact of all biomagnetic methods, because it offers a completely non-invasive and fast test for major heart diseases and risks, including heart infarction.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The contrast in low-field MRI is not as good as in high-field MRI, but may be sufficient for some diagnostic uses.

    “The contrast in low field is not as good as in high, but may be sufficient for some diagnostic uses.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    Good prospects exist for liver susceptometry in the early detection of genetic hemochromatosis, before it becomes symptomatic and difficult to treat.

    “Good prospects exist also for its use in the early detection of genetic hemochromatosis, before it becomes symptomatic and difficult to treat.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Most current clinical studies concentrate on various aspects of coronary artery (ischemic) disease (CAD), while others address the diagnostics of arrhythmias.

    “Most of the current clinical studies concentrate on various aspects of coronary artery (ischemic) disease (CAD), others address the diagnostics of arrhythmias”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    Overall, biomagnetism using SQUID is currently underutilized.

    “Overall, biomagnetism using SQUID is currently underutilized.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    Provided that data quality is not impaired, unshielded MCG systems should be advantageous in clinical environments.

    “Provided that the quality of data is not impaired, unshielded systems should be advantageous in clinical environments.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    In vivo application of superparamagnetic markers is a promising perspective, especially if current research into breast cancer detection proves successful.

    “A promising perspective is the in vivo application of superparamagnetic markers, especially if the current research into breast cancer detection proves successful [51].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [51] Wikswo J P, 2004, Phys. Today source

  • May combine two claims.

    Interpretationcitation

    Deviation from the generally valid orthogonality of electric and magnetic fields can be caused by conduction anisotropy of the heart muscle, which might also contribute to the non-equivalence of MCG and BSPM (ECG).

    “Deviation from the generally valid orthogonality of electric and magnetic fields can be caused by the conduction anisotropy of the heart muscle, which might also contribute to the non-equivalence of MCG and BSPM (ECG) [32].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [32] Kosch O Meindl P Steinhoff U Trahms L Nenonen J Ilmoniemi R J Katila T, 2001, Biomag 2000: Proc. 12th Int. Conf. on Biomagnetism

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The first MRI experiments in the millitesla range were pioneered a decade ago by Seton et al and involved tuned amplifiers.

    “The first MRI experiments in the millitesla range were pioneered a decade ago by Seton et al and involved tuned amplifiers [39,40].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [39] Haacke E A, 2000, Magnetic Resonance Imaging: Physical Principles and Sequence Design

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [40] source

  • May combine two claims.

    Interpretationreasoning

    Foetal MCG has a good chance of broader acceptance because foetal ECG cannot be used over a part of gestation when the foetus is electrically insulated by vernix caseosa.

    “Foetal MCG studies have been progressing for years and the method has a good chance of broader acceptance, because foetal ECG cannot be used over a part of gestation period-the foetus is then electrically insulated by a wax layer (vernix caseosa).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Foetal ECG cannot be used over a part of gestation period because the foetus is electrically insulated by vernix caseosa.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    MCG is ideally suitable for population screening and non-invasive monitoring of drug therapy.

    “It is also ideally suitable for population screening and non-invasive monitoring of drug therapy.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    In contrast to MEG, MCG entered only recently into the phase of extensive and statistically significant clinical trials in Europe and in USA.

    “In contrast to MEG, this method entered only recently into the phase of extensive and statistically significant clinical trials in Europe and in USA.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    When practical LFMRI systems become available, they will be inherently more patient-friendly (open, quiet) and should also be less expensive than whole-body high-field systems.

    “When practical LFMRI systems become available, they will be inherently more patient-friendly (open, quiet), and should also be less expensive than whole-body high-field systems.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationnone given

    Obstacles to MCG acceptance include competition from other novel methods such as cardiac MRI, the high cryogenic barrier, relatively high investment cost, and conservatism of cardiologists with preference for anatomical imaging.

    “Among obstacles to acceptance, we mention here the competition of other novel methods such as cardiac MRI, the high 'cryogenic barrier', relatively high investment cost (although much lower than that of cardiac MRI), and a certain conservatism of cardiologists and their clear preference for anatomical imaging.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    LFMRI offers the possibility to image in the presence of metal implants and biopsy needles, which is impossible with high-field MRI.

    “Furthermore, LFMRI offers the possibility to image in the presence of metal implants and biopsy needles, which is impossible with highfield MRI.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    Fusion of functional and anatomical imaging modalities could tremendously improve the accuracy of functional localization and make methods such as MEG and MCG much more attractive.

    “This fusion of modalities could tremendously improve the accuracy of functional localization, and make methods such as MEG and MCG much more attractive.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    In MCG, more technical evolution can be expected, especially if the method becomes broadly accepted in clinical medicine.

    “In MCG, one can expect more technical evolution, especially if the method becomes broadly accepted in clinical medicine.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Due to especially low signal levels, MNG will always require very effective and thus expensive magnetic shielding.

    “However, due to especially low signal levels, MNG will always require very effective and thus expensive magnetic shielding.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    The general trend in SQUID hardware should be towards closed-cycle cooling systems with reliable and quiet cryocoolers.

    “The general trend in SQUID hardware should be towards closed-cycle cooling systems with reliable and quiet cryocoolers.”
    Quote in the paperNot a substantial claim
81 of 81

  • The paper relies on this without support.

    Biological systems are in most cases rather complex and have a number of degrees of freedom exceeding the number of sensors to measure them.

    “Also, biological systems are in most cases rather complex and have a number of degrees of freedom exceeding the number of sensors to measure them.”

  • The paper relies on this without support.

    Patients are frequently attached to other mobile apparatus, may be clinically unstable or tending to claustrophobia.

    “However, in practice this concept may not be applicable, because patients are frequently attached to other mobile apparatus, may be clinically unstable or tending to claustrophobia.”

  • The paper relies on this without support.

    Even moderately effective MSRs are quite expensive and greatly impair the flexibility of using a biomagnetic method in real-life clinical environments.

    “Unfortunately, even moderately effective MSRs are quite expensive and greatly impair the flexibility of using a biomagnetic method in real-life clinical environments.”

  • The paper relies on this without support.

    Only mechanical cryocoolers can meet the requirements for safe, reliable, relatively inexpensive and invisible cryogenic cooling.

    “Only mechanical cryocoolers can meet such requirements.”

  • The paper relies on this without support.

    The 3D inverse problem is ill-defined.

    “Fundamentally, the 3D inverse problem is ill-defined.”

  • The paper relies on this without support.

    There are no databases from which precise rules for interpreting MCG recordings can be deduced.

    “the interpretation of MCG recordings is a challenge for cardiologists, since there are no databases from which precise rules can be deduced.”

  • The paper relies on this without support.

    Machine learning is typically powerful for handling missing information problems.

    “It is typically powerful for handling so-called missing information problems.”

  • The paper relies on this without support.

    Livers of normal subjects contain 50-500 µg g -1 of iron, while pathological iron overload can extend up to 5000 µg g -1.

    “Livers of normal subjects contain 50-500 µg g -1 , while pathological iron overload can extend up to 5000 µg g -1 .”

  • The paper relies on this without support.

    Foetal ECG cannot be used over a part of gestation period because the foetus is electrically insulated by vernix caseosa.

    “foetal ECG cannot be used over a part of gestation period-the foetus is then electrically insulated by a wax layer (vernix caseosa).”
9 of 9

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Rabbit-heart example cites the catheter paper

    Minor

    The rabbit-heart verification is cited as [22], but reference 22 concerns catheter localization. Reference 23 is the listed study of cardiac tissue and bidomain properties.

  • Catheter example cites a brain-imaging paper

    Minor

    The catheter-verification example cites [21], which is listed as a neuromagnetic FOCUSS paper. The listed catheter-localization paper is [22].

  • BabySQUID description cites an unrelated reference

    Minor

    The babySQUID description cites [25], which is listed as a general MEG signal-processing paper. The babySQUID system paper is listed as [26].

  • Breast-cancer marker claim cites a brain-magnetism article

    Minor

    The breast-cancer detection claim cites [51], which is listed as an article about measuring the brain's magnetic field. Reference 52 is the listed paper on in vivo cancer imaging.

  • Chest-pain claim cites a fetal-MEG paper

    Minor

    The claim about predicting coronary artery disease from acute chest pain cites [27], whose listed topic is fetal MEG. Reference 28 is the listed chest-pain and coronary-disease study.

  • FOCUSS citation points to the wrong reference

    Minor

    The discussion cites [20] for FOCUSS, but reference 20 is about minimum-norm estimates. The reference explicitly titled as a FOCUSS algorithm is [21].

  • Cardiomagnetic optical-sensor citation is misnumbered

    Minor

    The MCG optical-magnetometer example cites [49], listed as a three-axis atomic-magnetometer paper. The listed study mapping the human cardiomagnetic field with an optical sensor is [50].

7 of 7

Cites

Flagged first, then by citations

Research works printed but not linked: 8

  1. Andrä W, 1998, Magnetism in Medicine
  2. Lima E, 2006, SQUID Handbook, II
  3. Vrba J, 2006, SQUID Handbook, II
  4. Sachse F B Werner C D Stenroos M H Schulte R F Zerfass P Dössel O, 2000, Proc. 3rd Users Conf. of the National Library of Medicine’s Visible Human Project
  5. Tolstrup K, 2004, Circulation, 110, PIII-743
  6. Kosch O Meindl P Steinhoff U Trahms L Nenonen J Ilmoniemi R J Katila T, 2001, Biomag 2000: Proc. 12th Int. Conf. on Biomagnetism, 553
  7. Embrechts M, 2003, IEEE Int. Conf. on Systems, Man and Cybernetics, l2, 1400
  8. Matlachov A N Volegov P L Espy M A George J S Kraus R H Jr Halgren E Ahlfors S Hämäläinen M Cohen D, 2004, Proc. BIOMAG 2004, 39

Cited by

Sorted by citations

Related

Authors
Sternickel, K., & Braginski, A. I.
Affiliations
Forschungszentrum Jülich (DE)
Venue
Superconductor Science and Technology
Publisher
IOP Publishing
Published
2006-02-15
Volume
19
Issue
3
Pages
S160-S171
ISSN
  • 0953-2048 (ISSN-L)
  • 1361-6668
DOI
10.1088/0953-2048/19/3/024
OpenAlex
W2041287130
Cited by
180
References
44
Citations by year
2026: 12 · 2025: 10 · 2024: 13 · 2023: 14 · 2022: 12 · 2021: 12 · 2020: 9 · 2019: 9 · 2018: 12 · 2017: 7 · 2016: 4 · 2015: 4 · 2014: 9 · 2013: 14 · 2012: 5
FWCI
4.72
Type
journal article
Language
en
Open access
Locations
  • Superconductor Science and Technology (publishedVersion)
  • JuSER (Forschungszentrum Jülich) (submittedVersion)
Funders
  • National Science Foundation (0349580)
  • Vanderbilt University
Topics
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Atomic and Subatomic Physics Research
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Magnetic Field Sensors Techniques
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Geomagnetism and Paleomagnetism Studies
Keywords
biomagnetism, SQUID sensors, magnetoencephalography, magnetocardiography, low-field MRI, electromagnetic noise suppression, medical diagnostics, brain magnetic fields

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-11.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-11.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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