README.md

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license: apache-2.0
language:
- en
pipeline_tag: summarization
widget:
- text: 'the need for magnetic resonance imaging ( mri ) in patients with an implanted
    pacemaker or implantable cardioverter - defibrillator ( icd ) is a growing clinical
    issue . it is estimated that as many as 75% of active cardiac device recipients
    will become indicated for mri . currently , the vast majority of such devices
    are contraindicated for use with an mri . in european heart rhythm association
    survey , published recently for non - mri - certified icds ( 0.51.5 t field strength
    ) , the totally subcutaneous icd ( s - icd ) system , an implantable defibrillator
    with no leads that touch the heart , has recently been demonstrated to be a safe
    and effective defibrillator option for patients at risk for sudden cardiac death
    . it provides shock therapy and post - shock pacing therapy , but no long - term
    bradycardia pacing . although it has been shown as an alternative to the standard
    transvenous icd , its compatibility with mri remains unclear . various types of
    clinical mri systems currently use a superconductive magnet that creates a static
    magnetic field strength , typically 1.5 or 3 t. the use of mri with most pacemakers
    and icds is considered a contraindication due to potential hazards , including
    heating of the electrode that resides in or on the heart , damage to myocardium
    , elevation of pacing thresholds , unintended induction of ventricular tachycardia
    ( vt ) or ventricular fibrillation ( vf ) , pacing inhibition , permanent device
    malfunction , and distortion of the mri scan . recently , mr - conditional. mr
    - conditional indicates a lack of known hazards in a specified mri environment
    with specified conditions of use . due to the variety of mri scanners and scanning
    protocols , it is not practical to test even a single device under all conditions
    . hence , mr - conditional labelling dictates that the device is safe for use
    under certain scanning conditions , as well as how the cardiac device should be
    programmed before an exposure to the magnetic field in a mri scanner . the literature
    , although limited , provides some guidance for imaging patients with implanted
    pacemakers or icds that do not have mr - conditional labelling . this single -
    centre prospective non - controlled study describes the first use of mri in patients
    with an implanted s - icd . patients with implanted s - icd systems ( boston scientific
    sqrx model 1010 and q - trak model 3010 ) were enrolled for mri testing over a
    period of 18 months . the s - icd system implanted in this patient cohort was
    composed of a can implanted in a left mid - lateral pocket and a para - sternal
    subcutaneous electrode . the s - icd is currently not certified for use with an
    mri ; therefore , the ethics committee of homolka hospital , prague , czech republic
    approved our clinical study . patients with newly implanted s - icd systems (
    < 6 weeks ) were excluded , and none of the patients had any intravascular leads
    . the patients were randomized for either a cardiac , brain , cervical , or lumbar
    spinal scan . one of the subjects underwent an additional knee examination , due
    to reported chronic pain . a total of 15 patients were enrolled into this study
    ( 12 males and three females , aged 2283 years , mean 53 years . subjects in our
    cohort ( table 1 ) underwent a total of 22 mri scans between 6 june 2012 and 24
    december 2013 . in total , five brain scans , three cardiac scans , 12 lumbar
    scans , one knee , and one cervical spine scan were conducted ( table 2 ) . however
    , in one patient a minor disc protrusion was found , in other mri revealed stenosis
    of intervertebral foramen which was causing radicular pain of the nerve root l4
    and based on this examination the patient was referred to ct - navigated periradicular
    therapy . table 1summary of patient anatomical data and scan locations , along
    with noted clinical eventsidagesexbmidgef , % indication for s - icdheating0164f20.5hcmp
    / vfs85secondary preventionnone0283m30.0post - mi / smvts post - catheter ablation/35secondary
    prevention ( post - transvenous icd extraction)none0331m25.3arvc / d / smvts68secondary
    preventionin - tolerable re - scanned0458m23.6post - mi / post - cabg30primary
    preventionnone0577m25.5post - mi30primary preventionnone0663m27.0post - mi30primary
    preventionnone0768m23.7post - mi / vfs / vts60secondary prevention post - transvenous
    icd extraction / svc occlusiontolerable0822m29.4brugada sy / vfs68secondary preventionin
    - tolerable re - scanned0959m27.1dcmp / vfs / post - mitral valve surgery/60secondary
    prev./post - transvenous icd extractionnone1041f24.6arvc / d70primary preventionnone1123f21.5lqts
    / vf60secondary preventionnone1266m36.9post - mi / vf / post - cabg50secondary
    prevention / post - repeat transvenous icd extractiontolerable1348m22.9dcmp(non
    - compaction)/vfs35secondary preventionnone1470m29systolic dysfunction of lv35primary
    preventionnone1526m33brugada sy65primary preventionnonehcmp , hypertrophic cardiomyopathy
    ; smvt , sustained monomorphic ventricular tachycardia ; mi , myocardial infarction
    ; arvc , arrhythmogenic right ventricular cardiomyopathy ; cabg , coronary artery
    by - pass graft ; lqts , long qt syndrom . table 2parmeters of s - icd and patient
    sensation during individual mri scansscan # idbody partheating sensationsshock
    zone ( b.p.m.)condit . shock zone ( b.p.m.)bat % episode num.101brainnone2302101001202brainnone240220861303l
    spinein - tolerable240220831403brainnone240220831504brainnone220190691605l spinenone220210541706l
    spinenone240220681807l spinetolerable240220582908l spinein - tolerablenananana1008brainnonenananana1108l
    spinenone2302108411209heartnone2402208911310l spinenone2301807911410heartnonenananana1511heartnone2301909711612l
    spinetolerable2001709721712l spinenone2001709421813c spinenone23019010041913l
    spinenone23019010042014l spinenone2301908612115kneenone25021010012215l spinenone2502101001s
    - icd parameters acquired prior- and post - mri were without any change , therefore
    only one value is presented.indices : na , not available ; l spine , lumbar spine
    ; c spine , cervical spine . summary of patient anatomical data and scan locations
    , along with noted clinical events hcmp , hypertrophic cardiomyopathy ; smvt ,
    sustained monomorphic ventricular tachycardia ; mi , myocardial infarction ; arvc
    , arrhythmogenic right ventricular cardiomyopathy ; cabg , coronary artery by
    - pass graft ; lqts , long qt syndrom . parmeters of s - icd and patient sensation
    during individual mri scans s - icd parameters acquired prior- and post - mri
    were without any change , therefore only one value is presented . indices : na
    , not available ; l spine , lumbar spine ; c spine , cervical spine . studies
    were performed using a siemens avanto 1.5 t mri scanner ( vb17 software , quantum
    gradient coils ) . all scans were run in normal operating mode , which is limited
    to 2 w / kg whole body averaged specific absorption rate ( sar ) . clinically
    relevant mri sequences were used for evaluation ( see table 3 ) . table 3types
    of pulse sequences typically used for imaging of respective anatomical areasscan
    locationscan sequencesflairdwiflashfsehastesestirtruefispbrainxxxxheartxxxxcervical
    spinexxkneexxxxlumbar spinexxflair , fluid attenuated inversion recovery ; dwi
    , diffusion weighted imaging ; flash , fast low angle shot ; fse , fast spin echo
    ; haste , half acquisition single - shot turbo spin echo ; se , spin echo ; stir
    , short tau inversion recovery ; truefisp , true fast imaging with steady - state
    precession.fse sequence caused heating in subjects with a thermistor probe during
    lumbar spine examination ( see the text for details ) . types of pulse sequences
    typically used for imaging of respective anatomical areas flair , fluid attenuated
    inversion recovery ; dwi , diffusion weighted imaging ; flash , fast low angle
    shot ; fse , fast spin echo ; haste , half acquisition single - shot turbo spin
    echo ; se , spin echo ; stir , short tau inversion recovery ; truefisp , true
    fast imaging with steady - state precession . fse sequence caused heating in subjects
    with a thermistor probe during lumbar spine examination ( see the text for details
    ) . patients were asked to report immediately any pain , torqueing movement ,
    or heating sensation in the area of the pocket or the electrode by pressing an
    emergency bulb . furthermore , all patients were questioned immediately following
    the mri procedure to ascertain any discomfort in the vicinity of the can or electrode
    . pulse oximetry and standard lead electrocardiogram ( ecg ) if discomfort occurred
    , the patient was asked if the scan could be repeated at a later time using a
    revised scan sequence or the subject was again randomized for another anatomical
    area . since none of the components of the s - icd system are on or in the heart
    , heating near or around however , heating near the electrode or can with the
    s - icd system may still cause serious patient discomfort . therefore , along
    with education of subjects , each patient was instrumented by taping an oesophageal
    temperature probe ( beta - therm model g22k7mcd8 ) on the skin over the mid -
    lateral implant site to record any temperature excursions that might be correlated
    to patient symptoms of heating / discomfort near the pocket . to minimize the
    risk of inappropriate therapy , the s - icd system was programmed to therapy each
    s - icd system was evaluated prior to and immediately after the scan to verify
    proper functioning , including interrogation , sensing , and battery voltage .
    after the completion of the mri , long - term regular clinical follow - up and
    checking of the device were performed . patients with implanted s - icd systems
    ( boston scientific sqrx model 1010 and q - trak model 3010 ) were enrolled for
    mri testing over a period of 18 months . the s - icd system implanted in this
    patient cohort was composed of a can implanted in a left mid - lateral pocket
    and a para - sternal subcutaneous electrode . the s - icd is currently not certified
    for use with an mri ; therefore , the ethics committee of homolka hospital , prague
    , czech republic approved our clinical study . patients with newly implanted s
    - icd systems ( < 6 weeks ) were excluded , and none of the patients had any intravascular
    leads . the patients were randomized for either a cardiac , brain , cervical ,
    or lumbar spinal scan . one of the subjects underwent an additional knee examination
    , due to reported chronic pain . a total of 15 patients were enrolled into this
    study ( 12 males and three females , aged 2283 years , mean 53 years . subjects
    in our cohort ( table 1 ) underwent a total of 22 mri scans between 6 june 2012
    and 24 december 2013 . in total , five brain scans , three cardiac scans , 12
    lumbar scans , one knee , and one cervical spine scan were conducted ( table 2
    ) . however , in one patient a minor disc protrusion was found , in other mri
    revealed stenosis of intervertebral foramen which was causing radicular pain of
    the nerve root l4 and based on this examination the patient was referred to ct
    - navigated periradicular therapy . table 1summary of patient anatomical data
    and scan locations , along with noted clinical eventsidagesexbmidgef , % indication
    for s - icdheating0164f20.5hcmp / vfs85secondary preventionnone0283m30.0post -
    mi / smvts post - catheter ablation/35secondary prevention ( post - transvenous
    icd extraction)none0331m25.3arvc / d / smvts68secondary preventionin - tolerable
    re - scanned0458m23.6post - mi / post - cabg30primary preventionnone0577m25.5post
    - mi30primary preventionnone0663m27.0post - mi30primary preventionnone0768m23.7post
    - mi / vfs / vts60secondary prevention post - transvenous icd extraction / svc
    occlusiontolerable0822m29.4brugada sy / vfs68secondary preventionin - tolerable
    re - scanned0959m27.1dcmp / vfs / post - mitral valve surgery/60secondary prev./post
    - transvenous icd extractionnone1041f24.6arvc / d70primary preventionnone1123f21.5lqts
    / vf60secondary preventionnone1266m36.9post - mi / vf / post - cabg50secondary
    prevention / post - repeat transvenous icd extractiontolerable1348m22.9dcmp(non
    - compaction)/vfs35secondary preventionnone1470m29systolic dysfunction of lv35primary
    preventionnone1526m33brugada sy65primary preventionnonehcmp , hypertrophic cardiomyopathy
    ; smvt , sustained monomorphic ventricular tachycardia ; mi , myocardial infarction
    ; arvc , arrhythmogenic right ventricular cardiomyopathy ; cabg , coronary artery
    by - pass graft ; lqts , long qt syndrom . table 2parmeters of s - icd and patient
    sensation during individual mri scansscan # idbody partheating sensationsshock
    zone ( b.p.m.)condit . shock zone ( b.p.m.)bat % episode num.101brainnone2302101001202brainnone240220861303l
    spinein - tolerable240220831403brainnone240220831504brainnone220190691605l spinenone220210541706l
    spinenone240220681807l spinetolerable240220582908l spinein - tolerablenananana1008brainnonenananana1108l
    spinenone2302108411209heartnone2402208911310l spinenone2301807911410heartnonenananana1511heartnone2301909711612l
    spinetolerable2001709721712l spinenone2001709421813c spinenone23019010041913l
    spinenone23019010042014l spinenone2301908612115kneenone25021010012215l spinenone2502101001s
    - icd parameters acquired prior- and post - mri were without any change , therefore
    only one value is presented.indices : na , not available ; l spine , lumbar spine
    ; c spine , cervical spine . summary of patient anatomical data and scan locations
    , along with noted clinical events hcmp , hypertrophic cardiomyopathy ; smvt ,
    sustained monomorphic ventricular tachycardia ; mi , myocardial infarction ; arvc
    , arrhythmogenic right ventricular cardiomyopathy ; cabg , coronary artery by
    - pass graft ; lqts , long qt syndrom . parmeters of s - icd and patient sensation
    during individual mri scans s - icd parameters acquired prior- and post - mri
    were without any change , therefore only one value is presented . indices : na
    , not available ; l spine , lumbar spine ; c spine , cervical spine . studies
    were performed using a siemens avanto 1.5 t mri scanner ( vb17 software , quantum
    gradient coils ) . all scans were run in normal operating mode , which is limited
    to 2 w / kg whole body averaged specific absorption rate ( sar ) . clinically
    relevant mri sequences were used for evaluation ( see table 3 ) . table 3types
    of pulse sequences typically used for imaging of respective anatomical areasscan
    locationscan sequencesflairdwiflashfsehastesestirtruefispbrainxxxxheartxxxxcervical
    spinexxkneexxxxlumbar spinexxflair , fluid attenuated inversion recovery ; dwi
    , diffusion weighted imaging ; flash , fast low angle shot ; fse , fast spin echo
    ; haste , half acquisition single - shot turbo spin echo ; se , spin echo ; stir
    , short tau inversion recovery ; truefisp , true fast imaging with steady - state
    precession.fse sequence caused heating in subjects with a thermistor probe during
    lumbar spine examination ( see the text for details ) . types of pulse sequences
    typically used for imaging of respective anatomical areas flair , fluid attenuated
    inversion recovery ; dwi , diffusion weighted imaging ; flash , fast low angle
    shot ; fse , fast spin echo ; haste , half acquisition single - shot turbo spin
    echo ; se , spin echo ; stir , short tau inversion recovery ; truefisp , true
    fast imaging with steady - state precession . fse sequence caused heating in subjects
    with a thermistor probe during lumbar spine examination ( see the text for details
    ) . patients were asked to report immediately any pain , torqueing movement ,
    or heating sensation in the area of the pocket or the electrode by pressing an
    emergency bulb . furthermore , all patients were questioned immediately following
    the mri procedure to ascertain any discomfort in the vicinity of the can or electrode
    . pulse oximetry and standard lead electrocardiogram ( ecg ) if discomfort occurred
    , the patient was asked if the scan could be repeated at a later time using a
    revised scan sequence or the subject was again randomized for another anatomical
    area . since none of the components of the s - icd system are on or in the heart
    , heating near or around the electrode can not harm the myocardium . however ,
    heating near the electrode or can with the s - icd system may still cause serious
    patient discomfort . therefore , along with education of subjects , each patient
    was instrumented by taping an oesophageal temperature probe ( beta - therm model
    g22k7mcd8 ) on the skin over the mid - lateral implant site to record any temperature
    excursions that might be correlated to patient symptoms of heating / discomfort
    near the pocket . to minimize the risk of inappropriate therapy , the s - icd
    system was programmed to therapy each s - icd system was evaluated prior to and
    immediately after the scan to verify proper functioning , including interrogation
    , sensing , and battery voltage . after the completion of the mri , the s - icd
    system was reprogrammed to original settings . long - term regular clinical follow
    - up and checking of the device were performed . no anomalies were noted via pulse
    oximetry or ecg during the scans for any of the patients . eleven of 15 patients
    reported no sensation or pain from heating of the can , two of 15 patients reported
    feeling some heating , and two patients reported intolerable heating ( see table
    2 ) . in patients with intolerable heating , the scan was halted within seconds
    and changed to a scan of the brain , which proceeded without incident . patient
    reports of heating in the vicinity of the can occurred only during lumbar scans
    with a thermistor probe ; no such reports occurred during scans of the brain ,
    cardiac area , cervical spine , or without the probe . in two cases where heating
    in the vicinity of the can was reported by the patient , the scan sequence was
    altered to reduce the intensity of radiofrequency ( rf ) field exposure by reducing
    the turbo factor ( e.g. from 21 to 7 ) , increasing the repetition time ( e.g.
    to > 4000 ms ) , and reducing the flip angle ( e.g. from 170 to 120 ) . the target
    values were chosen arbitrarily to maintain image contrast ( flip angle ) and keep
    scan time at reasonable limits ( turbo factor and repetition time ) . less heating
    was noted by patients after these modifications to the scan parameters were made
    . 03 ) was observed to have a skin lesion , appearing to be a circular rash or
    ulcer on the surface of the skin over the can , approximately 35 mm in diameter
    . the cause of this skin anomaly is not known ; it was later noted to have fully
    healed at a follow - up 10 days after the scan . to ascertain the effect of heating
    due to the instrumented thermistor catheter , the two patients who experienced
    the heating ( examinations 9 and 16 , see table 2 ) were rescanned several weeks
    later without the thermistor catheter in place ( examinations 11 and 17 ) . first
    , modified sequence ( with even lower amount of energy deposited in the tissue
    ) was used , which caused no heating . as no sensation was reported by the subjects
    , they were asked to report even a minimal discomfort , and the lumbar scans were
    performed using the same settings that resulted in heating with the thermistor
    catheter in place in the first imaging session . the results of the rescans revealed
    that no heating was felt by the patients when the thermistor catheter was absent
    . there were no noted changes to battery voltage , ability to detect the qrs signal
    or stored diagnostic data . pacing thresholds can not be assessed by the s - icd
    system , so this was not evaluated . none of the patients reported any pulling
    or twisting of the can or pain from heating of the s - icd electrode . for scans
    of the brain , lumbar spine , knee , and cervical spine , no effect from image
    artefact was noted in the anatomical area of interest . however , for scans of
    the cardiac area , image artefact was noted to interfere with the ability to see
    parts of the left ventricle , though the right ventricle of the heart was unaffected
    and could be imaged usefully . this was due to the can and not the electrode (
    see figure 1 ) , modifications to the protocol for the lumbar spine resulted in
    a lower signal - to - noise ratio ; however , the images remain in diagnostic
    quality ( see figure 2 ) . figure 1kinetic study in four - chamber view : the
    systolic ( a and c ) and diastolic ( b and d ) images of cine sequences , four
    - chamber view . the steady - state free precession ( ssfp ) sequence ( a and
    b ) shows more artefacts . in ssfp kinetic study , an inflow of dark blood from
    the left pulmonary veins was seen . it could be caused by s - icd but also by
    metallic ring in mitral annulus . the spoiled gradient echo ( gre ) sequence (
    c and d ) is better , but an artefact at the lateral wall is obvious . figure
    2lumbar spine imaging with icd : low sar t2 fse sequence ( upper image ) compared
    with normal t2 fse in the same subject ( lower image , for the scanning parameters
    see the discussion section ) . kinetic study in four - chamber view : the systolic
    ( a and c ) and diastolic ( b and d ) images of cine sequences , four - chamber
    view . the steady - state free precession ( ssfp ) sequence ( a and b ) shows
    more artefacts . in ssfp kinetic study , an inflow of dark blood from the left
    pulmonary veins was seen . it could be caused by s - icd but also by metallic
    ring in mitral annulus . the spoiled gradient echo ( gre ) sequence ( c and d
    ) is better , but an artefact at the lateral wall is obvious . lumbar spine imaging
    with icd : low sar t2 fse sequence ( upper image ) compared with normal t2 fse
    in the same subject ( lower image , for the scanning parameters see the discussion
    section ) . there were no noted changes to battery voltage , ability to detect
    the qrs signal or stored diagnostic data . pacing thresholds can not be assessed
    by the s - icd system , so this was not evaluated . none of the patients reported
    any pulling or twisting of the can or pain from heating of the s - icd electrode
    . for scans of the brain , lumbar spine , knee , and cervical spine , no effect
    from image artefact was noted in the anatomical area of interest . however , for
    scans of the cardiac area , image artefact was noted to interfere with the ability
    to see parts of the left ventricle , though the right ventricle of the heart was
    unaffected and could be imaged usefully . this was due to the can and not the
    electrode ( see figure 1 ) , modifications to the protocol for the lumbar spine
    resulted in a lower signal - to - noise ratio ; however , the images remain in
    diagnostic quality ( see figure 2 ) . figure 1kinetic study in four - chamber
    view : the systolic ( a and c ) and diastolic ( b and d ) images of cine sequences
    , four - chamber view . the steady - state free precession ( ssfp ) sequence (
    a and b ) shows more artefacts . in ssfp kinetic study , an inflow of dark blood
    from the left pulmonary veins was seen . it could be caused by s - icd but also
    by metallic ring in mitral annulus . the spoiled gradient echo ( gre ) sequence
    ( c and d ) is better , but an artefact at the lateral wall is obvious . figure
    2lumbar spine imaging with icd : low sar t2 fse sequence ( upper image ) compared
    with normal t2 fse in the same subject ( lower image , for the scanning parameters
    see the discussion section ) . kinetic study in four - chamber view : the systolic
    ( a and c ) and diastolic ( b and d ) images of cine sequences , four - chamber
    view . the steady - state free precession ( ssfp ) sequence ( a and b ) shows
    more artefacts . in ssfp kinetic study , an inflow of dark blood from the left
    pulmonary veins was seen . it could be caused by s - icd but also by metallic
    ring in mitral annulus . the spoiled gradient echo ( gre ) sequence ( c and d
    ) is better , but an artefact at the lateral wall is obvious . lumbar spine imaging
    with icd : low sar t2 fse sequence ( upper image ) compared with normal t2 fse
    in the same subject ( lower image , there are several reports in the current literature
    about mr - conditional pacemakers from several companies , but very limited reports
    about mr - conditional icds . biotronik announced in late 2011 release of their
    first mr - compatible icd device and defibrillator leads pro mri , but in the
    conditions of use excluded scanning of the torso and focused more on the extremities
    examination . in european heart rhythm association survey , 60% of centres did
    not implant any mri - certified icds , 34.3% implanted < 10 icd devices , and
    only 5.6% implanted 10 and more icds ; one - fifth of responders stated that mri
    - certified icds should be implanted in all patients but lack of reimbursement
    was indicated as a possible obstacle to implant more mri - certified pacemakers
    / icds by 47.1% of responding centres . none of the components of the s - icd
    system are on or in the heart . the s - icd depends less upon being in direct
    contact with the myocardium to function and instead uses far - field sensing and
    stimulation to provide the shock and post - shock pacing therapy . as a consequence
    , unlike transvenous systems heating near or around the electrode can not harm
    the myocardium , which could present with possible safety consequences such as
    an elevation in pacing thresholds or scarring of the myocardium , but it may still
    cause serious patient discomfort . because the s - icd is larger than modern transvenous
    icd ''s , there may be more potential for the can to experience heating due to
    the magnetic gradient or rf field . we report results from what we believe is
    the first experience of mri scanning in patients with an implanted s - icd and
    in various anatomical areas . overall , mri was performed safely in all patients
    , which is in contrast to the current literature with mri imaging in patients
    with electrical - active devices which are not mri - conditional . in our study
    , the primary clinically significant event attributable to the mri scan was the
    occurrence of heating in the area of the pocket in the four patients that underwent
    lumbar scans . it was not known if this was due to the s - icd can itself or an
    artefact of the thermistor catheter used to measure skin temperature over the
    pocket . this required a revision of our protocol , which was to re - scan two
    of the patients who complained of heating . re - scanning of these patients without
    the thermistor probe resulted in no complaints of heating , so it is assumed that
    the thermistor catheter itself heated during the lumbar scans and caused the discomfort
    . as further evidence , all the heating complaints occurred during rf - intensive
    scan sequences ( namely fast spin echo ) with the temperature probe located axially
    near the centre of the bore , where rf fields are the highest . the thermistor
    catheter is constructed of insulated conductive cables connected to electrodes
    and should couple to the rf fields efficiently , causing heating at the electrodes
    and pain or damage on the surface of the skin where the probe was placed over
    the s - icd can . if the heating was due to the s - icd can itself , it would
    more likely occur during gradient - intensive scan sequences ( which can generate
    eddy currents on can surfaces and internal components ) and at locations in the
    bore where there are high gradient fields , such as near the bore edges . however
    , when the patient was scanned with gradient - intensive scan sequences ( e.g.
    flair dwi ) and with the s - icd system in high gradient field locations in the
    bore ( e.g. such as during a brain scan ) , patients did not detect any heating
    or discomfort . in addition , the subcutaneous lead , which was not instrumented
    with a thermistor catheter , never resulted in any heating sensation noted by
    the patient , even when exactly the same sequence that resulted in heating in
    the first session was used . the use of mri - compatible temperature monitors
    such as fibre optic temperature probes would have provided better confirmation
    of possible skin temperature elevation and would not have been affected by the
    rf fields . for cardiac imaging , the main problem to solve is metallic artefact
    , especially on the gradient - echo sequences . like in research performed by
    nazarian et al . , several scan protocols were used to see if any yielded different
    effects or reduced the qualitative extent of artefact . gradient mode was changed
    from normal to whisper , resulting in slower ramping of the field and therefore
    diminishing the changes of the magnetic field in time . artefacts when present
    were limited to blurring of the left ventricle during cardiac scans and most yielded
    clinically useful information . standard interrogation of the s - icd revealed
    no adverse effects upon the functioning of the system . while no adverse effects
    upon the post - scan s - icd device function were noted , not all possible scanning
    protocols were tested . it should be noted that , four of the s - icd ''s were
    exposed to repeat mri scans without adverse effects to device function . in addition
    , because the s - icd does not provide long - term bradycardia pacing , it is
    assumed that pacemaker - dependent patients would not be implanted with this system
    . the inhibition of the pacemaker function during the scanning sequence and possible
    pacing threshold changes are a unique concern in patients implanted with transvenous
    icds . this study included only 15 patients and 22 scans done on the same 1.5
    t mri scanner . thus , even these preliminary results should only be applied to
    1.5 t mri scanners ( similarly as reported in the present literature for other
    implantable devices ) . device functionality was tested immediately after the
    scan but not for long - term effects . in addition , not all device functions
    were tested although the s - icd system does have a beeper / interrogation warning
    if battery levels or memory irregularities occur . however , patients were scheduled
    for regular check - up and no defect of the device was observed in following 725
    months ( mean observation time 18 months ) . delayed enhancement mri for determining
    cardiac scarring was also not tested . also , there are other anatomical areas
    that were not evaluated , such as shoulder and knees . this study included only
    15 patients and 22 scans done on the same 1.5 t mri scanner . thus , even these
    preliminary results should only be applied to 1.5 t mri scanners ( similarly as
    reported in the present literature for other implantable devices ) . device functionality
    was tested immediately after the scan but not for long - term effects . in addition
    , not all device functions were tested although the s - icd system does have a
    beeper / interrogation warning if battery levels or memory irregularities occur
    . however , patients were scheduled for regular check - up and no defect of the
    device was observed in following 725 months ( mean observation time 18 months
    ) . delayed enhancement mri for determining cardiac scarring was also not tested
    . also , there are other anatomical areas that were not evaluated , such as shoulder
    and knees . while more data are required to support a claim of mri - conditional
    , this study is the study to demonstrate the feasibility of exposing s - icd patients
    to mri using the scanning and monitor protocol described , with some precautionary
    measures including : ( i ) programming the device therapy off ; ( ii ) limiting
    the sar to 2.0 w / kg ; ( iii ) continuous monitoring of the patients pulse oximetry
    and ecg by qualified personnel and especially for any feelings of heating ; (
    iv ) evaluate device function post scan ; ( v ) availability of full resuscitation
    facilities at the mri site . given the variables of different mri scanners , the
    decision to perform mri on patients with an implanted s - icd system should be
    balanced against the potential risks . in our study , the only heating was very
    likely introduced by not fully mri - compatible thermometer probe ; subjects rescanned
    without the probe did not report any abnormalities during the scan of any body
    area listed ( brain , cervical and lumbar spine , heart , and knee ) . this study
    was supported by iga mz r nt12094/2011 , research project charles university in
    prague , prvouk p34 and unce 204010/2012 . funding to pay the open access publication
    charges for this article was provided by iga mz r nt12094/2011 .'
example_title: Summarization Example 1
tags:
- medical
- llama-cpp
- gguf-my-repo
base_model: Falconsai/medical_summarization
---

# fernandoruiz/medical_summarization-Q4_0-GGUF
This model was converted to GGUF format from [`Falconsai/medical_summarization`](https://huggingface.co/Falconsai/medical_summarization) using llama.cpp via the ggml.ai's [GGUF-my-repo](https://huggingface.co/spaces/ggml-org/gguf-my-repo) space.
Refer to the [original model card](https://huggingface.co/Falconsai/medical_summarization) for more details on the model.

## Use with llama.cpp
Install llama.cpp through brew (works on Mac and Linux)

```bash
brew install llama.cpp

```
Invoke the llama.cpp server or the CLI.

### CLI:
```bash
llama-cli --hf-repo fernandoruiz/medical_summarization-Q4_0-GGUF --hf-file medical_summarization-q4_0.gguf -p "The meaning to life and the universe is"
```

### Server:
```bash
llama-server --hf-repo fernandoruiz/medical_summarization-Q4_0-GGUF --hf-file medical_summarization-q4_0.gguf -c 2048
```

Note: You can also use this checkpoint directly through the [usage steps](https://github.com/ggerganov/llama.cpp?tab=readme-ov-file#usage) listed in the Llama.cpp repo as well.

Step 1: Clone llama.cpp from GitHub.
```
git clone https://github.com/ggerganov/llama.cpp
```

Step 2: Move into the llama.cpp folder and build it with `LLAMA_CURL=1` flag along with other hardware-specific flags (for ex: LLAMA_CUDA=1 for Nvidia GPUs on Linux).
```
cd llama.cpp && LLAMA_CURL=1 make
```

Step 3: Run inference through the main binary.
```
./llama-cli --hf-repo fernandoruiz/medical_summarization-Q4_0-GGUF --hf-file medical_summarization-q4_0.gguf -p "The meaning to life and the universe is"
```
or 
```
./llama-server --hf-repo fernandoruiz/medical_summarization-Q4_0-GGUF --hf-file medical_summarization-q4_0.gguf -c 2048
```