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1
+ ---
2
+ license: apache-2.0
3
+ language:
4
+ - en
5
+ pipeline_tag: summarization
6
+ widget:
7
+ - text: 'the need for magnetic resonance imaging ( mri ) in patients with an implanted
8
+ pacemaker or implantable cardioverter - defibrillator ( icd ) is a growing clinical
9
+ issue . it is estimated that as many as 75% of active cardiac device recipients
10
+ will become indicated for mri . currently , the vast majority of such devices
11
+ are contraindicated for use with an mri . in european heart rhythm association
12
+ survey , published recently for non - mri - certified icds ( 0.51.5 t field strength
13
+ ) , the totally subcutaneous icd ( s - icd ) system , an implantable defibrillator
14
+ with no leads that touch the heart , has recently been demonstrated to be a safe
15
+ and effective defibrillator option for patients at risk for sudden cardiac death
16
+ . it provides shock therapy and post - shock pacing therapy , but no long - term
17
+ bradycardia pacing . although it has been shown as an alternative to the standard
18
+ transvenous icd , its compatibility with mri remains unclear . various types of
19
+ clinical mri systems currently use a superconductive magnet that creates a static
20
+ magnetic field strength , typically 1.5 or 3 t. the use of mri with most pacemakers
21
+ and icds is considered a contraindication due to potential hazards , including
22
+ heating of the electrode that resides in or on the heart , damage to myocardium
23
+ , elevation of pacing thresholds , unintended induction of ventricular tachycardia
24
+ ( vt ) or ventricular fibrillation ( vf ) , pacing inhibition , permanent device
25
+ malfunction , and distortion of the mri scan . recently , mr - conditional. mr
26
+ - conditional indicates a lack of known hazards in a specified mri environment
27
+ with specified conditions of use . due to the variety of mri scanners and scanning
28
+ protocols , it is not practical to test even a single device under all conditions
29
+ . hence , mr - conditional labelling dictates that the device is safe for use
30
+ under certain scanning conditions , as well as how the cardiac device should be
31
+ programmed before an exposure to the magnetic field in a mri scanner . the literature
32
+ , although limited , provides some guidance for imaging patients with implanted
33
+ pacemakers or icds that do not have mr - conditional labelling . this single -
34
+ centre prospective non - controlled study describes the first use of mri in patients
35
+ with an implanted s - icd . patients with implanted s - icd systems ( boston scientific
36
+ sqrx model 1010 and q - trak model 3010 ) were enrolled for mri testing over a
37
+ period of 18 months . the s - icd system implanted in this patient cohort was
38
+ composed of a can implanted in a left mid - lateral pocket and a para - sternal
39
+ subcutaneous electrode . the s - icd is currently not certified for use with an
40
+ mri ; therefore , the ethics committee of homolka hospital , prague , czech republic
41
+ approved our clinical study . patients with newly implanted s - icd systems (
42
+ < 6 weeks ) were excluded , and none of the patients had any intravascular leads
43
+ . the patients were randomized for either a cardiac , brain , cervical , or lumbar
44
+ spinal scan . one of the subjects underwent an additional knee examination , due
45
+ to reported chronic pain . a total of 15 patients were enrolled into this study
46
+ ( 12 males and three females , aged 2283 years , mean 53 years . subjects in our
47
+ cohort ( table 1 ) underwent a total of 22 mri scans between 6 june 2012 and 24
48
+ december 2013 . in total , five brain scans , three cardiac scans , 12 lumbar
49
+ scans , one knee , and one cervical spine scan were conducted ( table 2 ) . however
50
+ , in one patient a minor disc protrusion was found , in other mri revealed stenosis
51
+ of intervertebral foramen which was causing radicular pain of the nerve root l4
52
+ and based on this examination the patient was referred to ct - navigated periradicular
53
+ therapy . table 1summary of patient anatomical data and scan locations , along
54
+ with noted clinical eventsidagesexbmidgef , % indication for s - icdheating0164f20.5hcmp
55
+ / vfs85secondary preventionnone0283m30.0post - mi / smvts post - catheter ablation/35secondary
56
+ prevention ( post - transvenous icd extraction)none0331m25.3arvc / d / smvts68secondary
57
+ preventionin - tolerable re - scanned0458m23.6post - mi / post - cabg30primary
58
+ preventionnone0577m25.5post - mi30primary preventionnone0663m27.0post - mi30primary
59
+ preventionnone0768m23.7post - mi / vfs / vts60secondary prevention post - transvenous
60
+ icd extraction / svc occlusiontolerable0822m29.4brugada sy / vfs68secondary preventionin
61
+ - tolerable re - scanned0959m27.1dcmp / vfs / post - mitral valve surgery/60secondary
62
+ prev./post - transvenous icd extractionnone1041f24.6arvc / d70primary preventionnone1123f21.5lqts
63
+ / vf60secondary preventionnone1266m36.9post - mi / vf / post - cabg50secondary
64
+ prevention / post - repeat transvenous icd extractiontolerable1348m22.9dcmp(non
65
+ - compaction)/vfs35secondary preventionnone1470m29systolic dysfunction of lv35primary
66
+ preventionnone1526m33brugada sy65primary preventionnonehcmp , hypertrophic cardiomyopathy
67
+ ; smvt , sustained monomorphic ventricular tachycardia ; mi , myocardial infarction
68
+ ; arvc , arrhythmogenic right ventricular cardiomyopathy ; cabg , coronary artery
69
+ by - pass graft ; lqts , long qt syndrom . table 2parmeters of s - icd and patient
70
+ sensation during individual mri scansscan # idbody partheating sensationsshock
71
+ zone ( b.p.m.)condit . shock zone ( b.p.m.)bat % episode num.101brainnone2302101001202brainnone240220861303l
72
+ spinein - tolerable240220831403brainnone240220831504brainnone220190691605l spinenone220210541706l
73
+ spinenone240220681807l spinetolerable240220582908l spinein - tolerablenananana1008brainnonenananana1108l
74
+ spinenone2302108411209heartnone2402208911310l spinenone2301807911410heartnonenananana1511heartnone2301909711612l
75
+ spinetolerable2001709721712l spinenone2001709421813c spinenone23019010041913l
76
+ spinenone23019010042014l spinenone2301908612115kneenone25021010012215l spinenone2502101001s
77
+ - icd parameters acquired prior- and post - mri were without any change , therefore
78
+ only one value is presented.indices : na , not available ; l spine , lumbar spine
79
+ ; c spine , cervical spine . summary of patient anatomical data and scan locations
80
+ , along with noted clinical events hcmp , hypertrophic cardiomyopathy ; smvt ,
81
+ sustained monomorphic ventricular tachycardia ; mi , myocardial infarction ; arvc
82
+ , arrhythmogenic right ventricular cardiomyopathy ; cabg , coronary artery by
83
+ - pass graft ; lqts , long qt syndrom . parmeters of s - icd and patient sensation
84
+ during individual mri scans s - icd parameters acquired prior- and post - mri
85
+ were without any change , therefore only one value is presented . indices : na
86
+ , not available ; l spine , lumbar spine ; c spine , cervical spine . studies
87
+ were performed using a siemens avanto 1.5 t mri scanner ( vb17 software , quantum
88
+ gradient coils ) . all scans were run in normal operating mode , which is limited
89
+ to 2 w / kg whole body averaged specific absorption rate ( sar ) . clinically
90
+ relevant mri sequences were used for evaluation ( see table 3 ) . table 3types
91
+ of pulse sequences typically used for imaging of respective anatomical areasscan
92
+ locationscan sequencesflairdwiflashfsehastesestirtruefispbrainxxxxheartxxxxcervical
93
+ spinexxkneexxxxlumbar spinexxflair , fluid attenuated inversion recovery ; dwi
94
+ , diffusion weighted imaging ; flash , fast low angle shot ; fse , fast spin echo
95
+ ; haste , half acquisition single - shot turbo spin echo ; se , spin echo ; stir
96
+ , short tau inversion recovery ; truefisp , true fast imaging with steady - state
97
+ precession.fse sequence caused heating in subjects with a thermistor probe during
98
+ lumbar spine examination ( see the text for details ) . types of pulse sequences
99
+ typically used for imaging of respective anatomical areas flair , fluid attenuated
100
+ inversion recovery ; dwi , diffusion weighted imaging ; flash , fast low angle
101
+ shot ; fse , fast spin echo ; haste , half acquisition single - shot turbo spin
102
+ echo ; se , spin echo ; stir , short tau inversion recovery ; truefisp , true
103
+ fast imaging with steady - state precession . fse sequence caused heating in subjects
104
+ with a thermistor probe during lumbar spine examination ( see the text for details
105
+ ) . patients were asked to report immediately any pain , torqueing movement ,
106
+ or heating sensation in the area of the pocket or the electrode by pressing an
107
+ emergency bulb . furthermore , all patients were questioned immediately following
108
+ the mri procedure to ascertain any discomfort in the vicinity of the can or electrode
109
+ . pulse oximetry and standard lead electrocardiogram ( ecg ) if discomfort occurred
110
+ , the patient was asked if the scan could be repeated at a later time using a
111
+ revised scan sequence or the subject was again randomized for another anatomical
112
+ area . since none of the components of the s - icd system are on or in the heart
113
+ , heating near or around however , heating near the electrode or can with the
114
+ s - icd system may still cause serious patient discomfort . therefore , along
115
+ with education of subjects , each patient was instrumented by taping an oesophageal
116
+ temperature probe ( beta - therm model g22k7mcd8 ) on the skin over the mid -
117
+ lateral implant site to record any temperature excursions that might be correlated
118
+ to patient symptoms of heating / discomfort near the pocket . to minimize the
119
+ risk of inappropriate therapy , the s - icd system was programmed to therapy each
120
+ s - icd system was evaluated prior to and immediately after the scan to verify
121
+ proper functioning , including interrogation , sensing , and battery voltage .
122
+ after the completion of the mri , long - term regular clinical follow - up and
123
+ checking of the device were performed . patients with implanted s - icd systems
124
+ ( boston scientific sqrx model 1010 and q - trak model 3010 ) were enrolled for
125
+ mri testing over a period of 18 months . the s - icd system implanted in this
126
+ patient cohort was composed of a can implanted in a left mid - lateral pocket
127
+ and a para - sternal subcutaneous electrode . the s - icd is currently not certified
128
+ for use with an mri ; therefore , the ethics committee of homolka hospital , prague
129
+ , czech republic approved our clinical study . patients with newly implanted s
130
+ - icd systems ( < 6 weeks ) were excluded , and none of the patients had any intravascular
131
+ leads . the patients were randomized for either a cardiac , brain , cervical ,
132
+ or lumbar spinal scan . one of the subjects underwent an additional knee examination
133
+ , due to reported chronic pain . a total of 15 patients were enrolled into this
134
+ study ( 12 males and three females , aged 2283 years , mean 53 years . subjects
135
+ in our cohort ( table 1 ) underwent a total of 22 mri scans between 6 june 2012
136
+ and 24 december 2013 . in total , five brain scans , three cardiac scans , 12
137
+ lumbar scans , one knee , and one cervical spine scan were conducted ( table 2
138
+ ) . however , in one patient a minor disc protrusion was found , in other mri
139
+ revealed stenosis of intervertebral foramen which was causing radicular pain of
140
+ the nerve root l4 and based on this examination the patient was referred to ct
141
+ - navigated periradicular therapy . table 1summary of patient anatomical data
142
+ and scan locations , along with noted clinical eventsidagesexbmidgef , % indication
143
+ for s - icdheating0164f20.5hcmp / vfs85secondary preventionnone0283m30.0post -
144
+ mi / smvts post - catheter ablation/35secondary prevention ( post - transvenous
145
+ icd extraction)none0331m25.3arvc / d / smvts68secondary preventionin - tolerable
146
+ re - scanned0458m23.6post - mi / post - cabg30primary preventionnone0577m25.5post
147
+ - mi30primary preventionnone0663m27.0post - mi30primary preventionnone0768m23.7post
148
+ - mi / vfs / vts60secondary prevention post - transvenous icd extraction / svc
149
+ occlusiontolerable0822m29.4brugada sy / vfs68secondary preventionin - tolerable
150
+ re - scanned0959m27.1dcmp / vfs / post - mitral valve surgery/60secondary prev./post
151
+ - transvenous icd extractionnone1041f24.6arvc / d70primary preventionnone1123f21.5lqts
152
+ / vf60secondary preventionnone1266m36.9post - mi / vf / post - cabg50secondary
153
+ prevention / post - repeat transvenous icd extractiontolerable1348m22.9dcmp(non
154
+ - compaction)/vfs35secondary preventionnone1470m29systolic dysfunction of lv35primary
155
+ preventionnone1526m33brugada sy65primary preventionnonehcmp , hypertrophic cardiomyopathy
156
+ ; smvt , sustained monomorphic ventricular tachycardia ; mi , myocardial infarction
157
+ ; arvc , arrhythmogenic right ventricular cardiomyopathy ; cabg , coronary artery
158
+ by - pass graft ; lqts , long qt syndrom . table 2parmeters of s - icd and patient
159
+ sensation during individual mri scansscan # idbody partheating sensationsshock
160
+ zone ( b.p.m.)condit . shock zone ( b.p.m.)bat % episode num.101brainnone2302101001202brainnone240220861303l
161
+ spinein - tolerable240220831403brainnone240220831504brainnone220190691605l spinenone220210541706l
162
+ spinenone240220681807l spinetolerable240220582908l spinein - tolerablenananana1008brainnonenananana1108l
163
+ spinenone2302108411209heartnone2402208911310l spinenone2301807911410heartnonenananana1511heartnone2301909711612l
164
+ spinetolerable2001709721712l spinenone2001709421813c spinenone23019010041913l
165
+ spinenone23019010042014l spinenone2301908612115kneenone25021010012215l spinenone2502101001s
166
+ - icd parameters acquired prior- and post - mri were without any change , therefore
167
+ only one value is presented.indices : na , not available ; l spine , lumbar spine
168
+ ; c spine , cervical spine . summary of patient anatomical data and scan locations
169
+ , along with noted clinical events hcmp , hypertrophic cardiomyopathy ; smvt ,
170
+ sustained monomorphic ventricular tachycardia ; mi , myocardial infarction ; arvc
171
+ , arrhythmogenic right ventricular cardiomyopathy ; cabg , coronary artery by
172
+ - pass graft ; lqts , long qt syndrom . parmeters of s - icd and patient sensation
173
+ during individual mri scans s - icd parameters acquired prior- and post - mri
174
+ were without any change , therefore only one value is presented . indices : na
175
+ , not available ; l spine , lumbar spine ; c spine , cervical spine . studies
176
+ were performed using a siemens avanto 1.5 t mri scanner ( vb17 software , quantum
177
+ gradient coils ) . all scans were run in normal operating mode , which is limited
178
+ to 2 w / kg whole body averaged specific absorption rate ( sar ) . clinically
179
+ relevant mri sequences were used for evaluation ( see table 3 ) . table 3types
180
+ of pulse sequences typically used for imaging of respective anatomical areasscan
181
+ locationscan sequencesflairdwiflashfsehastesestirtruefispbrainxxxxheartxxxxcervical
182
+ spinexxkneexxxxlumbar spinexxflair , fluid attenuated inversion recovery ; dwi
183
+ , diffusion weighted imaging ; flash , fast low angle shot ; fse , fast spin echo
184
+ ; haste , half acquisition single - shot turbo spin echo ; se , spin echo ; stir
185
+ , short tau inversion recovery ; truefisp , true fast imaging with steady - state
186
+ precession.fse sequence caused heating in subjects with a thermistor probe during
187
+ lumbar spine examination ( see the text for details ) . types of pulse sequences
188
+ typically used for imaging of respective anatomical areas flair , fluid attenuated
189
+ inversion recovery ; dwi , diffusion weighted imaging ; flash , fast low angle
190
+ shot ; fse , fast spin echo ; haste , half acquisition single - shot turbo spin
191
+ echo ; se , spin echo ; stir , short tau inversion recovery ; truefisp , true
192
+ fast imaging with steady - state precession . fse sequence caused heating in subjects
193
+ with a thermistor probe during lumbar spine examination ( see the text for details
194
+ ) . patients were asked to report immediately any pain , torqueing movement ,
195
+ or heating sensation in the area of the pocket or the electrode by pressing an
196
+ emergency bulb . furthermore , all patients were questioned immediately following
197
+ the mri procedure to ascertain any discomfort in the vicinity of the can or electrode
198
+ . pulse oximetry and standard lead electrocardiogram ( ecg ) if discomfort occurred
199
+ , the patient was asked if the scan could be repeated at a later time using a
200
+ revised scan sequence or the subject was again randomized for another anatomical
201
+ area . since none of the components of the s - icd system are on or in the heart
202
+ , heating near or around the electrode can not harm the myocardium . however ,
203
+ heating near the electrode or can with the s - icd system may still cause serious
204
+ patient discomfort . therefore , along with education of subjects , each patient
205
+ was instrumented by taping an oesophageal temperature probe ( beta - therm model
206
+ g22k7mcd8 ) on the skin over the mid - lateral implant site to record any temperature
207
+ excursions that might be correlated to patient symptoms of heating / discomfort
208
+ near the pocket . to minimize the risk of inappropriate therapy , the s - icd
209
+ system was programmed to therapy each s - icd system was evaluated prior to and
210
+ immediately after the scan to verify proper functioning , including interrogation
211
+ , sensing , and battery voltage . after the completion of the mri , the s - icd
212
+ system was reprogrammed to original settings . long - term regular clinical follow
213
+ - up and checking of the device were performed . no anomalies were noted via pulse
214
+ oximetry or ecg during the scans for any of the patients . eleven of 15 patients
215
+ reported no sensation or pain from heating of the can , two of 15 patients reported
216
+ feeling some heating , and two patients reported intolerable heating ( see table
217
+ 2 ) . in patients with intolerable heating , the scan was halted within seconds
218
+ and changed to a scan of the brain , which proceeded without incident . patient
219
+ reports of heating in the vicinity of the can occurred only during lumbar scans
220
+ with a thermistor probe ; no such reports occurred during scans of the brain ,
221
+ cardiac area , cervical spine , or without the probe . in two cases where heating
222
+ in the vicinity of the can was reported by the patient , the scan sequence was
223
+ altered to reduce the intensity of radiofrequency ( rf ) field exposure by reducing
224
+ the turbo factor ( e.g. from 21 to 7 ) , increasing the repetition time ( e.g.
225
+ to > 4000 ms ) , and reducing the flip angle ( e.g. from 170 to 120 ) . the target
226
+ values were chosen arbitrarily to maintain image contrast ( flip angle ) and keep
227
+ scan time at reasonable limits ( turbo factor and repetition time ) . less heating
228
+ was noted by patients after these modifications to the scan parameters were made
229
+ . 03 ) was observed to have a skin lesion , appearing to be a circular rash or
230
+ ulcer on the surface of the skin over the can , approximately 35 mm in diameter
231
+ . the cause of this skin anomaly is not known ; it was later noted to have fully
232
+ healed at a follow - up 10 days after the scan . to ascertain the effect of heating
233
+ due to the instrumented thermistor catheter , the two patients who experienced
234
+ the heating ( examinations 9 and 16 , see table 2 ) were rescanned several weeks
235
+ later without the thermistor catheter in place ( examinations 11 and 17 ) . first
236
+ , modified sequence ( with even lower amount of energy deposited in the tissue
237
+ ) was used , which caused no heating . as no sensation was reported by the subjects
238
+ , they were asked to report even a minimal discomfort , and the lumbar scans were
239
+ performed using the same settings that resulted in heating with the thermistor
240
+ catheter in place in the first imaging session . the results of the rescans revealed
241
+ that no heating was felt by the patients when the thermistor catheter was absent
242
+ . there were no noted changes to battery voltage , ability to detect the qrs signal
243
+ or stored diagnostic data . pacing thresholds can not be assessed by the s - icd
244
+ system , so this was not evaluated . none of the patients reported any pulling
245
+ or twisting of the can or pain from heating of the s - icd electrode . for scans
246
+ of the brain , lumbar spine , knee , and cervical spine , no effect from image
247
+ artefact was noted in the anatomical area of interest . however , for scans of
248
+ the cardiac area , image artefact was noted to interfere with the ability to see
249
+ parts of the left ventricle , though the right ventricle of the heart was unaffected
250
+ and could be imaged usefully . this was due to the can and not the electrode (
251
+ see figure 1 ) , modifications to the protocol for the lumbar spine resulted in
252
+ a lower signal - to - noise ratio ; however , the images remain in diagnostic
253
+ quality ( see figure 2 ) . figure 1kinetic study in four - chamber view : the
254
+ systolic ( a and c ) and diastolic ( b and d ) images of cine sequences , four
255
+ - chamber view . the steady - state free precession ( ssfp ) sequence ( a and
256
+ b ) shows more artefacts . in ssfp kinetic study , an inflow of dark blood from
257
+ the left pulmonary veins was seen . it could be caused by s - icd but also by
258
+ metallic ring in mitral annulus . the spoiled gradient echo ( gre ) sequence (
259
+ c and d ) is better , but an artefact at the lateral wall is obvious . figure
260
+ 2lumbar spine imaging with icd : low sar t2 fse sequence ( upper image ) compared
261
+ with normal t2 fse in the same subject ( lower image , for the scanning parameters
262
+ see the discussion section ) . kinetic study in four - chamber view : the systolic
263
+ ( a and c ) and diastolic ( b and d ) images of cine sequences , four - chamber
264
+ view . the steady - state free precession ( ssfp ) sequence ( a and b ) shows
265
+ more artefacts . in ssfp kinetic study , an inflow of dark blood from the left
266
+ pulmonary veins was seen . it could be caused by s - icd but also by metallic
267
+ ring in mitral annulus . the spoiled gradient echo ( gre ) sequence ( c and d
268
+ ) is better , but an artefact at the lateral wall is obvious . lumbar spine imaging
269
+ with icd : low sar t2 fse sequence ( upper image ) compared with normal t2 fse
270
+ in the same subject ( lower image , for the scanning parameters see the discussion
271
+ section ) . there were no noted changes to battery voltage , ability to detect
272
+ the qrs signal or stored diagnostic data . pacing thresholds can not be assessed
273
+ by the s - icd system , so this was not evaluated . none of the patients reported
274
+ any pulling or twisting of the can or pain from heating of the s - icd electrode
275
+ . for scans of the brain , lumbar spine , knee , and cervical spine , no effect
276
+ from image artefact was noted in the anatomical area of interest . however , for
277
+ scans of the cardiac area , image artefact was noted to interfere with the ability
278
+ to see parts of the left ventricle , though the right ventricle of the heart was
279
+ unaffected and could be imaged usefully . this was due to the can and not the
280
+ electrode ( see figure 1 ) , modifications to the protocol for the lumbar spine
281
+ resulted in a lower signal - to - noise ratio ; however , the images remain in
282
+ diagnostic quality ( see figure 2 ) . figure 1kinetic study in four - chamber
283
+ view : the systolic ( a and c ) and diastolic ( b and d ) images of cine sequences
284
+ , four - chamber view . the steady - state free precession ( ssfp ) sequence (
285
+ a and b ) shows more artefacts . in ssfp kinetic study , an inflow of dark blood
286
+ from the left pulmonary veins was seen . it could be caused by s - icd but also
287
+ by metallic ring in mitral annulus . the spoiled gradient echo ( gre ) sequence
288
+ ( c and d ) is better , but an artefact at the lateral wall is obvious . figure
289
+ 2lumbar spine imaging with icd : low sar t2 fse sequence ( upper image ) compared
290
+ with normal t2 fse in the same subject ( lower image , for the scanning parameters
291
+ see the discussion section ) . kinetic study in four - chamber view : the systolic
292
+ ( a and c ) and diastolic ( b and d ) images of cine sequences , four - chamber
293
+ view . the steady - state free precession ( ssfp ) sequence ( a and b ) shows
294
+ more artefacts . in ssfp kinetic study , an inflow of dark blood from the left
295
+ pulmonary veins was seen . it could be caused by s - icd but also by metallic
296
+ ring in mitral annulus . the spoiled gradient echo ( gre ) sequence ( c and d
297
+ ) is better , but an artefact at the lateral wall is obvious . lumbar spine imaging
298
+ with icd : low sar t2 fse sequence ( upper image ) compared with normal t2 fse
299
+ in the same subject ( lower image , there are several reports in the current literature
300
+ about mr - conditional pacemakers from several companies , but very limited reports
301
+ about mr - conditional icds . biotronik announced in late 2011 release of their
302
+ first mr - compatible icd device and defibrillator leads pro mri , but in the
303
+ conditions of use excluded scanning of the torso and focused more on the extremities
304
+ examination . in european heart rhythm association survey , 60% of centres did
305
+ not implant any mri - certified icds , 34.3% implanted < 10 icd devices , and
306
+ only 5.6% implanted 10 and more icds ; one - fifth of responders stated that mri
307
+ - certified icds should be implanted in all patients but lack of reimbursement
308
+ was indicated as a possible obstacle to implant more mri - certified pacemakers
309
+ / icds by 47.1% of responding centres . none of the components of the s - icd
310
+ system are on or in the heart . the s - icd depends less upon being in direct
311
+ contact with the myocardium to function and instead uses far - field sensing and
312
+ stimulation to provide the shock and post - shock pacing therapy . as a consequence
313
+ , unlike transvenous systems heating near or around the electrode can not harm
314
+ the myocardium , which could present with possible safety consequences such as
315
+ an elevation in pacing thresholds or scarring of the myocardium , but it may still
316
+ cause serious patient discomfort . because the s - icd is larger than modern transvenous
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+ icd ''s , there may be more potential for the can to experience heating due to
318
+ the magnetic gradient or rf field . we report results from what we believe is
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+ the first experience of mri scanning in patients with an implanted s - icd and
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+ in various anatomical areas . overall , mri was performed safely in all patients
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+ , which is in contrast to the current literature with mri imaging in patients
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+ with electrical - active devices which are not mri - conditional . in our study
323
+ , the primary clinically significant event attributable to the mri scan was the
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+ occurrence of heating in the area of the pocket in the four patients that underwent
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+ lumbar scans . it was not known if this was due to the s - icd can itself or an
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+ artefact of the thermistor catheter used to measure skin temperature over the
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+ pocket . this required a revision of our protocol , which was to re - scan two
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+ of the patients who complained of heating . re - scanning of these patients without
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+ the thermistor probe resulted in no complaints of heating , so it is assumed that
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+ the thermistor catheter itself heated during the lumbar scans and caused the discomfort
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+ . as further evidence , all the heating complaints occurred during rf - intensive
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+ scan sequences ( namely fast spin echo ) with the temperature probe located axially
333
+ near the centre of the bore , where rf fields are the highest . the thermistor
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+ catheter is constructed of insulated conductive cables connected to electrodes
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+ and should couple to the rf fields efficiently , causing heating at the electrodes
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+ and pain or damage on the surface of the skin where the probe was placed over
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+ the s - icd can . if the heating was due to the s - icd can itself , it would
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+ more likely occur during gradient - intensive scan sequences ( which can generate
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+ eddy currents on can surfaces and internal components ) and at locations in the
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+ bore where there are high gradient fields , such as near the bore edges . however
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+ , when the patient was scanned with gradient - intensive scan sequences ( e.g.
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+ flair dwi ) and with the s - icd system in high gradient field locations in the
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+ bore ( e.g. such as during a brain scan ) , patients did not detect any heating
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+ or discomfort . in addition , the subcutaneous lead , which was not instrumented
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+ with a thermistor catheter , never resulted in any heating sensation noted by
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+ the patient , even when exactly the same sequence that resulted in heating in
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+ the first session was used . the use of mri - compatible temperature monitors
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+ such as fibre optic temperature probes would have provided better confirmation
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+ of possible skin temperature elevation and would not have been affected by the
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+ rf fields . for cardiac imaging , the main problem to solve is metallic artefact
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+ , especially on the gradient - echo sequences . like in research performed by
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+ nazarian et al . , several scan protocols were used to see if any yielded different
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+ effects or reduced the qualitative extent of artefact . gradient mode was changed
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+ from normal to whisper , resulting in slower ramping of the field and therefore
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+ diminishing the changes of the magnetic field in time . artefacts when present
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+ were limited to blurring of the left ventricle during cardiac scans and most yielded
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+ clinically useful information . standard interrogation of the s - icd revealed
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+ no adverse effects upon the functioning of the system . while no adverse effects
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+ upon the post - scan s - icd device function were noted , not all possible scanning
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+ protocols were tested . it should be noted that , four of the s - icd ''s were
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+ exposed to repeat mri scans without adverse effects to device function . in addition
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+ , because the s - icd does not provide long - term bradycardia pacing , it is
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+ assumed that pacemaker - dependent patients would not be implanted with this system
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+ . the inhibition of the pacemaker function during the scanning sequence and possible
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+ pacing threshold changes are a unique concern in patients implanted with transvenous
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+ icds . this study included only 15 patients and 22 scans done on the same 1.5
367
+ t mri scanner . thus , even these preliminary results should only be applied to
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+ 1.5 t mri scanners ( similarly as reported in the present literature for other
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+ implantable devices ) . device functionality was tested immediately after the
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+ scan but not for long - term effects . in addition , not all device functions
371
+ were tested although the s - icd system does have a beeper / interrogation warning
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+ if battery levels or memory irregularities occur . however , patients were scheduled
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+ for regular check - up and no defect of the device was observed in following 725
374
+ months ( mean observation time 18 months ) . delayed enhancement mri for determining
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+ cardiac scarring was also not tested . also , there are other anatomical areas
376
+ that were not evaluated , such as shoulder and knees . this study included only
377
+ 15 patients and 22 scans done on the same 1.5 t mri scanner . thus , even these
378
+ preliminary results should only be applied to 1.5 t mri scanners ( similarly as
379
+ reported in the present literature for other implantable devices ) . device functionality
380
+ was tested immediately after the scan but not for long - term effects . in addition
381
+ , not all device functions were tested although the s - icd system does have a
382
+ beeper / interrogation warning if battery levels or memory irregularities occur
383
+ . however , patients were scheduled for regular check - up and no defect of the
384
+ device was observed in following 725 months ( mean observation time 18 months
385
+ ) . delayed enhancement mri for determining cardiac scarring was also not tested
386
+ . also , there are other anatomical areas that were not evaluated , such as shoulder
387
+ and knees . while more data are required to support a claim of mri - conditional
388
+ , this study is the study to demonstrate the feasibility of exposing s - icd patients
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+ to mri using the scanning and monitor protocol described , with some precautionary
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+ measures including : ( i ) programming the device therapy off ; ( ii ) limiting
391
+ the sar to 2.0 w / kg ; ( iii ) continuous monitoring of the patients pulse oximetry
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+ and ecg by qualified personnel and especially for any feelings of heating ; (
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+ iv ) evaluate device function post scan ; ( v ) availability of full resuscitation
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+ facilities at the mri site . given the variables of different mri scanners , the
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+ decision to perform mri on patients with an implanted s - icd system should be
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+ balanced against the potential risks . in our study , the only heating was very
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+ likely introduced by not fully mri - compatible thermometer probe ; subjects rescanned
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+ without the probe did not report any abnormalities during the scan of any body
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+ area listed ( brain , cervical and lumbar spine , heart , and knee ) . this study
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+ was supported by iga mz r nt12094/2011 , research project charles university in
401
+ prague , prvouk p34 and unce 204010/2012 . funding to pay the open access publication
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+ charges for this article was provided by iga mz r nt12094/2011 .'
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+ example_title: Summarization Example 1
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+ tags:
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+ - medical
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+ - llama-cpp
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+ - gguf-my-repo
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+ base_model: Falconsai/medical_summarization
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+ ---
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+
411
+ # fernandoruiz/medical_summarization-Q4_0-GGUF
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+ 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.
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+ Refer to the [original model card](https://huggingface.co/Falconsai/medical_summarization) for more details on the model.
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+
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+ ## Use with llama.cpp
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+ Install llama.cpp through brew (works on Mac and Linux)
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+
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+ ```bash
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+ brew install llama.cpp
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+
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+ ```
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+ Invoke the llama.cpp server or the CLI.
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+
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+ ### CLI:
425
+ ```bash
426
+ 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"
427
+ ```
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+
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+ ### Server:
430
+ ```bash
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+ llama-server --hf-repo fernandoruiz/medical_summarization-Q4_0-GGUF --hf-file medical_summarization-q4_0.gguf -c 2048
432
+ ```
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+
434
+ 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.
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+
436
+ Step 1: Clone llama.cpp from GitHub.
437
+ ```
438
+ git clone https://github.com/ggerganov/llama.cpp
439
+ ```
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+
441
+ 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).
442
+ ```
443
+ cd llama.cpp && LLAMA_CURL=1 make
444
+ ```
445
+
446
+ Step 3: Run inference through the main binary.
447
+ ```
448
+ ./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"
449
+ ```
450
+ or
451
+ ```
452
+ ./llama-server --hf-repo fernandoruiz/medical_summarization-Q4_0-GGUF --hf-file medical_summarization-q4_0.gguf -c 2048
453
+ ```