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Immohr MB, Boeken U, Smiris K, Erbel-Khurtsidze S, Oehler D, Dalyanoglu H, Westenfeld R, Aubin H, Tudorache I, Lichtenberg A, Akhyari P. Removal of Electrophysiological Devices in the Context of Heart Transplantation: Comparison of Combined and Staged Extraction Procedures. Thorac Cardiovasc Surg 2021; 70:467-474. [PMID: 34894633 DOI: 10.1055/s-0041-1736532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND During heart transplantation (HTx), tip of the leads of cardiac implantable electrophysiological devices (CIEPD) has to be cut when resecting the heart. Timing of the removal of the remaining device and leads is still discussed controversially. METHODS Between 2010 and 2021, n = 201 patients underwent HTx, of those n = 124 (61.7%) carried a present CIEPD. These patients were divided on the basis of the time of complete device removal (combined procedure with HTx, n = 40 or staged procedure, n = 84). RESULTS CIEPD was removed 11.4 ± 6.7 days after the initial HTx in staged patients. Dwelling time, number of leads as well as incidence of retained components (combined: 8.1%, staged: 7.7%, p = 1.00) were comparable between both groups. While postoperative incidence of infections (p = 0.52), neurological events (p = 0.47), and acute kidney injury (p = 0.44) did not differ, staged patients suffered more often from primary graft dysfunction with temporary mechanical assistance (combined: 20.0%, staged: 40.5%, p = 0.03). Consecutively, stay on intensive care unit (p = 0.02) was prolonged and transfusions of red blood cells (p = 0.15) and plasma (p = 0.06) as well as re-thoracotomy for thoracic bleeding complications (p = 0.10) were numerically increased in this group. However, we did not observe any differences in postoperative survival. CONCLUSION Presence of CIEPD is common in HTx patients. However, the extraction strategy of CIEPD most likely did not affect postoperative morbidity and mortality except primary graft dysfunction. Especially, retained components, blood transfusions, and infective complications are not correlated to the timing of CIEPD removal.
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Affiliation(s)
- Moritz Benjamin Immohr
- Department of Cardiac Surgery, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Udo Boeken
- Department of Cardiac Surgery, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Konstantinos Smiris
- Department of Cardiac Surgery, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | | | - Daniel Oehler
- Department of Cardiology, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Hannan Dalyanoglu
- Department of Cardiac Surgery, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Ralf Westenfeld
- Department of Cardiology, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Hug Aubin
- Department of Cardiac Surgery, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Igor Tudorache
- Department of Cardiac Surgery, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Artur Lichtenberg
- Department of Cardiac Surgery, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Payam Akhyari
- Department of Cardiac Surgery, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
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Yao A, Goren T, Samaras T, Kuster N, Kainz W. Radiofrequency-induced heating of broken and abandoned implant leads during magnetic resonance examinations. Magn Reson Med 2021; 86:2156-2164. [PMID: 34080721 PMCID: PMC8362172 DOI: 10.1002/mrm.28836] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/15/2021] [Accepted: 04/21/2021] [Indexed: 12/21/2022]
Abstract
Purpose The risks of RF‐induced heating of active implantable medical device (AIMD) leads during MR examinations must be well understood and realistically assessed. In this study, we evaluate the potential additional risks of broken and abandoned (cut) leads. Methods First, we defined a generic AIMD with a metallic implantable pulse generator (IPG) and a 100‐cm long lead containing 1 or 2 wires. Next, we numerically estimated the deposited in vitro lead‐tip power for an intact lead, as well as with wire breaks placed at 10 cm intervals. We studied the effect of the break size (wire gap width), as well as the presence of an intact wire parallel to the broken wire, and experimentally validated the numeric results for the configurations with maximum deposited in vitro lead‐tip power. Finally, we performed a Tier 3 assessment of the deposited in vivo lead‐tip power for the intact and broken lead in 4 high resolution virtual population anatomic models for over 54,000 MR examination scenarios. Results The enhancement of the deposited lead‐tip power for the broken leads, compared to the intact lead, reached 30‐fold in isoelectric exposure, and 16‐fold in realistic clinical exposures. The presence of a nearby intact wire, or even a nearby broken wire, reduced this enhancement factor to <7‐fold over the intact lead. Conclusion Broken and abandoned leads can pose increased risk of RF‐induced lead‐tip heating to patients undergoing MR examinations. The potential enhancement of deposited in vivo lead‐tip power depends on location and type of the wire break, lead design, and clinical routing of the lead, and should be carefully considered when performing risk assessment for MR examinations and MR conditional labeling.
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Affiliation(s)
- Aiping Yao
- Foundation of Research on Information Technologies in Society (IT'IS), Zurich, Switzerland
| | - Tolga Goren
- Foundation of Research on Information Technologies in Society (IT'IS), Zurich, Switzerland
| | - Theodoros Samaras
- Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Niels Kuster
- Foundation of Research on Information Technologies in Society (IT'IS), Zurich, Switzerland.,Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Wolfgang Kainz
- Center for Devices and Radiological Health, Food and Drug Administration (FDA), Silver Spring, Maryland, USA
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3
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Gatterer C, Stelzmüller ME, Kammerlander A, Zuckermann A, Krššák M, Loewe C, Beitzke D. Safety and image quality of cardiovascular magnetic resonance imaging in patients with retained epicardial pacing wires after heart transplantation. J Cardiovasc Magn Reson 2021; 23:24. [PMID: 33715632 PMCID: PMC7962314 DOI: 10.1186/s12968-021-00728-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/03/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Temporary epicardial pacing wires, implemented in patients during heart transplantation, are routinely removed before discharge. However, in some cases, these wires may remain in situ and are often considered as a contraindication for cardiovascular magnetic resonance (CMR) imaging in the future. Therefore, we aimed to provide data about safety and image quality of CMR in these patients. METHODS This is a report on a subpopulation out of 88 patients after heart transplantation that were included in a prospective cohort study and underwent multiple CMR in their post-transplant course. During CMR, patients were monitored by electrocardiogram and all examinations were observed by a physician to document potential adverse events. Additionally, image quality was assessed by an imaging specialist. RESULTS Nineteen of 88 patients included had temporary pacing wires in situ. These patients underwent a total of 51 CMR studies. No major adverse event and only one single, mild sensory event could be documented. All CMR studies showed preserved diagnostic image quality. Temporary pacing wires were visible in 100% of HASTE and cine sequences. In less than 50% of the examinations, temporary pacing wires were also visible in T1 and T2 mapping, short tau inversion recovery (STIR), and late gadolinium enhancement (LGE) sequences, without any impairment of image quality. CONCLUSIONS With a low event rate of only one mild adverse event during 51 CMR examinations (2%), CMR appears to be safe in patients with retained temporary epicardial pacing wires after heart transplantation. Moreover, image quality was not impaired by the presence of pacing wires.
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Affiliation(s)
- Constantin Gatterer
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
- Department of Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria
| | | | - Andreas Kammerlander
- Department of Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria
| | - Andreas Zuckermann
- Department of Surgery, Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Martin Krššák
- Department of Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Vienna, Austria
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, High-Field MR Centre, Vienna, Austria
| | - Christian Loewe
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Dietrich Beitzke
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.
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4
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Gopalakrishnan PP, Gevenosky L, Biederman RWW. Feasibility of MRI in patients with non-Pacemaker/Defibrillator metallic devices and abandoned leads. ACTA ACUST UNITED AC 2021; 14:83-93. [PMID: 33777288 DOI: 10.4236/jbise.2021.143009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Objective To evaluate feasibility of MRI in patients with non-pacemaker (PM)/ Implantable cardioverter defibrillator (ICD) metallic devices and abandoned leads. Background Relative safety of MRI performed using specified protocol has been established in MR non-conditional PM/ICDs. With limited safety data, many non-PM/ICD metallic devices and abandoned leads continue to be a contraindication for MRI. Methods We retrospectively analyzed consecutive patients with extra-cardiac devices, non-programmable cardiac devices, and abandoned leads, who underwent MRI (GE 1.5 Tesla, WI) at a single tertiary care center over a span of 13 years. Scan protocol was designed to maintain specific absorption rate (SAR) < 4.0 W/kg and scan time < 60 minutes. Results The cohort comprised 127 MRI exams representing 94 patients, with 13 patients having two or more scans. The devices consisted of: 23 vagal nerve stimulators (VNS), 22 implantable loop recorders, 16 spinal stimulators, 5 peripheral nerve stimulators, 3 bladder stimulators, 2 deep brain stimulators, 1 gastric stimulator, 1 bone stimulator, 1 WATCHMAN device, 22 abandoned PM/lCD leads and 1 VNS lead. There was no immediate (peri-MRI exam) morbidity or mortality. Patients did not report any discomfort, palpitations, heating, or sensation of device migration during the exam. Local follow-up data was available in 65% (100% for thoracic imaging) with a mean of 190±475 days (median 13 days). No device malfunction reported during follow-up. Conclusions With appropriate precautions, MRI is feasible in patients with extracardiac devices, nonprogrammable cardiac devices, and abandoned leads.
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Affiliation(s)
| | - Loretta Gevenosky
- Cardiovascular MRI Center, Allegheny Health Network Cardiovascular Institute, Pittsburgh, PA 15212
| | - Robert W W Biederman
- Cardiovascular MRI Center, Allegheny Health Network Cardiovascular Institute, Pittsburgh, PA 15212
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Fardman A, Ram E, Lavee J, Wieder A, Beinart R, Nof E, Peled Y. Complications of retained pacemaker hardware in heart transplant recipients: case series and review of the literature. Infection 2020; 48:635-640. [PMID: 32246271 DOI: 10.1007/s15010-020-01410-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/06/2020] [Indexed: 11/26/2022]
Abstract
Heart transplantation (HT) in patients with prior cardiovascular implantable electronic devices (CIEDs) is becoming more common, in parallel with the increased use of CIEDs for patients with advanced heart failure. Complete removal of CIED components during HT is not always feasible, and it is thus surprising that the literature addressing the implications of retained CIED components is limited. Indeed, there are neither guidelines nor consensus regarding the need for removal of these CIED fragments. This issue is nonetheless becoming important in light of the increase in the percentage of HT candidates having CIEDs, on the one hand, and newer therapeutic immunosuppressive protocols with higher bacterial infection potential, on the other. Thus, with the aim to study the implications of retained CIED fragments as a step towards establishing a therapeutic approach for the unique population of HT recipients with CIED remnants, we present here a case series of HT patients with retained CIED fragments who developed complications of infections together with a review of the available literature.
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Affiliation(s)
- Alexander Fardman
- Leviev Cardiothoracic and Vascular Center, Sheba Medical Center, Tel Hashomer, 52621, Ramat Gan, Israel.
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
| | - Eilon Ram
- Leviev Cardiothoracic and Vascular Center, Sheba Medical Center, Tel Hashomer, 52621, Ramat Gan, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Jacob Lavee
- Leviev Cardiothoracic and Vascular Center, Sheba Medical Center, Tel Hashomer, 52621, Ramat Gan, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Anat Wieder
- Infectious Disease Unit, Chaim Sheba Medical Center, Ramat Gan, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Roy Beinart
- Leviev Cardiothoracic and Vascular Center, Sheba Medical Center, Tel Hashomer, 52621, Ramat Gan, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Eyal Nof
- Leviev Cardiothoracic and Vascular Center, Sheba Medical Center, Tel Hashomer, 52621, Ramat Gan, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Yael Peled
- Leviev Cardiothoracic and Vascular Center, Sheba Medical Center, Tel Hashomer, 52621, Ramat Gan, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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Schillaci V, Mascia G, Shopova G, Chiariello P, Ciardiello C, Solimene F. Highly complicated lead extraction procedure in patient with previous early orthotopic heart transplantation: A first case report. Clin Case Rep 2018; 6:2319-2321. [PMID: 30564321 PMCID: PMC6293138 DOI: 10.1002/ccr3.1823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 08/05/2018] [Accepted: 08/26/2018] [Indexed: 11/07/2022] Open
Abstract
We report a first case of a highly complicated lead extraction in a young man who previously underwent orthotopic heart transplantation (OHT).Lead extraction in transplanted patients may be a feasible and safe procedure in order to maintain a low infective risk and to preserve alternative vascular access sites.
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7
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Alvarez PA, Sperry BW, Perez AL, Varian K, Raymond T, Tong M, Hussein AA, Taylor DO. Burden and consequences of retained cardiovascular implantable electronic device lead fragments after heart transplantation. Am J Transplant 2018; 18:3021-3028. [PMID: 29607624 DOI: 10.1111/ajt.14755] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 03/23/2018] [Accepted: 03/24/2018] [Indexed: 01/25/2023]
Abstract
We performed a retrospective review of 402 consecutive patients who underwent heart transplantation at our institution between January 2009 and March 2017. A retained cardiovascular implantable electronic device (CIED) fragment was identified after transplantation in 49 of the 301 patients (16.2%) with CIED at baseline. Patients with retained fragments had leads with longer dwell times (median 2596 [1982, 3389] vs 1384 [610, 2202] days, P < .001), higher prevalence of previously abandoned leads (14.3% vs 2.8%, P = .003), and dual-coil defibrillator leads (98% vs 81%, P = .001) compared with patients without retained fragments. Five patients (10%) with retained CIED fragments underwent magnetic resonance imaging without adverse events. There was no difference in overall mortality between patients with and without CIED fragments (12% vs 11%, P = .81) Patients with retained fragments located in the superior vena cava had significantly higher fluoroscopic times (3.3 vs 2.9 minutes, P = .024) during subsequent endomyocardial biopsies. In a competing risk analysis, presence of a retained CIED fragment was associated with upper extremity deep venous thrombosis (sub hazard ratio [HR] 2.19, 95% confidence interval [CI] 1.17-4.10, P = .014) but not bloodstream infection after adjusting for potential confounders. In summary, retained CIED fragments are common after heart transplantation, and are associated with longer radiation exposure during biopsy procedures and upper extremity deep venous thrombosis.
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Affiliation(s)
- Paulino A Alvarez
- Section of Advanced Heart Failure and Transplant Cardiology, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Brett W Sperry
- Section of Advanced Heart Failure and Transplant Cardiology, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Antonio L Perez
- Section of Advanced Heart Failure and Transplant Cardiology, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Kenneth Varian
- Section of Advanced Heart Failure and Transplant Cardiology, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Timothy Raymond
- Section of Advanced Heart Failure and Transplant Cardiology, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Michael Tong
- Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Ayman A Hussein
- Section of Cardiovascular Electrophysiology, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH USA
| | - David O Taylor
- Section of Advanced Heart Failure and Transplant Cardiology, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH, USA
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8
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Hasumi E, Fujiu K, Kojima T, Kinoshita O, Nawata K, Yamauchi H, Ono M, Komuro I. Novel extraction technique of retained pacemaker and defibrillator lead during heart transplantation. PLoS One 2018; 13:e0203172. [PMID: 30188917 PMCID: PMC6126868 DOI: 10.1371/journal.pone.0203172] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 08/15/2018] [Indexed: 12/24/2022] Open
Abstract
Background Removal of cardiac implantable electronic devices (CIEDs) by manual traction during orthotopic heart transplantation (OHT) sometimes results in retained lead fragments. Moreover, abandoned leads and retained lead fragments are a contraindication for magnetic resonance imaging (MRI) and may be a cause of CIED infection. Objective To eliminate complications of retained lead fragments, we completely removed residual leads using an excimer laser sheath technique during OHT. We report our clinical experience and high success rate of lead extraction using the excimer laser sheath compared with manual traction during OHT. Methods and results We obtained data on 84 consecutive patients receiving OHT between August 2007 and August 2017. Thirty-nine of 84 patients had undergone CIED implantation before OHT and removal of all their leads was attempted during OHT. From 2007 to 2014, defibrillator and pacemaker leads were extracted by manual traction in all patients (N = 22). After 2015, all leads were extracted with the excimer laser sheath, and surgical assistance was prepared for the procedure (N = 17). Complete procedural success was achieved in 100% of patients in the excimer laser group and 77% of patients in the manual traction group. Conclusion Extraction of abandoned leads using the excimer laser sheath system during OHT is novel and safe technique, and has a higher success rate than extraction using manual traction during OHT.
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Affiliation(s)
- Eriko Hasumi
- Department of Ubiquitous Health Informatics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- * E-mail: (EH); (KF)
| | - Katsuhito Fujiu
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Department of Advanced Cardiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- * E-mail: (EH); (KF)
| | - Toshiya Kojima
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Osamu Kinoshita
- Department of Cardiac Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kan Nawata
- Department of Cardiac Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Haruo Yamauchi
- Department of Cardiac Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Minoru Ono
- Department of Cardiac Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Issei Komuro
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Golestanirad L, Rahsepar AA, Kirsch JE, Suwa K, Collins JC, Angelone LM, Keil B, Passman RS, Bonmassar G, Serano P, Krenz P, DeLap J, Carr JC, Wald LL. Changes in the specific absorption rate (SAR) of radiofrequency energy in patients with retained cardiac leads during MRI at 1.5T and 3T. Magn Reson Med 2018; 81:653-669. [PMID: 29893997 PMCID: PMC6258273 DOI: 10.1002/mrm.27350] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 04/08/2018] [Accepted: 04/16/2018] [Indexed: 12/20/2022]
Abstract
PURPOSE To evaluate the local specific absorption rate (SAR) and heating around retained cardiac leads during MRI at 64 MHz (1.5T) and 127 MHz (3T) as a function of RF coil type and imaging landmark. METHODS Numerical models of retained cardiac leads were built from CT and X-ray images of 6 patients with retained cardiac leads. Electromagnetic simulations and bio-heat modeling were performed with MRI RF body and head coils tuned to 64 MHz and 127 MHz and positioned at 9 different imaging landmarks covering an area from the head to the lower limbs. RESULTS For all patients and at both 1.5T and 3T, local transmit head coils produced negligible temperature rise ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>Δ</mml:mo> <mml:mi>T</mml:mi> <mml:mo><</mml:mo> <mml:mn>0.1</mml:mn> <mml:mo>°</mml:mo> <mml:mi>C</mml:mi></mml:mrow> </mml:math> ) for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:mrow><mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo> <mml:mrow><mml:msubsup><mml:mi>B</mml:mi> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo></mml:msubsup> </mml:mrow> <mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo></mml:mrow> <mml:mo>≤</mml:mo> <mml:mn>3</mml:mn> <mml:mo> </mml:mo> <mml:mo>μ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> . For body imaging with quadrature-driven coils at 1.5T, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>Δ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> during a 10-min scan remained < 3°C at all imaging landmarks for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:mrow><mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo> <mml:mrow><mml:msubsup><mml:mi>B</mml:mi> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo></mml:msubsup> </mml:mrow> <mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo></mml:mrow> <mml:mo>≤</mml:mo> <mml:mn>3</mml:mn> <mml:mo> </mml:mo> <mml:mo>μ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> and <6°C for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:mrow><mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo> <mml:mrow><mml:msubsup><mml:mi>B</mml:mi> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo></mml:msubsup> </mml:mrow> <mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo></mml:mrow> <mml:mo>≤</mml:mo> <mml:mn>4</mml:mn> <mml:mo> </mml:mo> <mml:mo>μ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> . For body imaging at 3T, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>Δ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> during a 10-min scan remained < 6°C at all imaging landmarks for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:mrow><mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo> <mml:mrow><mml:msubsup><mml:mi>B</mml:mi> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo></mml:msubsup> </mml:mrow> <mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo></mml:mrow> <mml:mo>≤</mml:mo> <mml:mn>2</mml:mn> <mml:mo> </mml:mo> <mml:mo>μ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> . For shorter pulse sequences up to 2 min, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>Δ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> remained < 6°C for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:mrow><mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo> <mml:mrow><mml:msubsup><mml:mi>B</mml:mi> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo></mml:msubsup> </mml:mrow> <mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo></mml:mrow> <mml:mo>≤</mml:mo> <mml:mn>3</mml:mn> <mml:mo> </mml:mo> <mml:mo>μ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> . CONCLUSION For the models based on 6 patients studied, simulations suggest that MRI could be performed safely using a local head coil at both 1.5T and 3T, and with a body coil at 1.5T with pulses that produced <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:mrow><mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo> <mml:mrow><mml:msubsup><mml:mi>B</mml:mi> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo></mml:msubsup> </mml:mrow> <mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo></mml:mrow> <mml:mo>≤</mml:mo> <mml:mn>4</mml:mn> <mml:mo> </mml:mo> <mml:mo>μ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> . MRI at 3T could be performed safely in these patients using pulses with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:mrow><mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo> <mml:mrow><mml:msubsup><mml:mi>B</mml:mi> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo></mml:msubsup> </mml:mrow> <mml:mo>‖</mml:mo> <mml:mo>‖</mml:mo></mml:mrow> <mml:mo>≤</mml:mo> <mml:mn>2</mml:mn> <mml:mo> </mml:mo> <mml:mo>μ</mml:mo> <mml:mi>T</mml:mi></mml:mrow> </mml:math> .
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Affiliation(s)
- Laleh Golestanirad
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts.,Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Amir Ali Rahsepar
- Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - John E Kirsch
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Kenichiro Suwa
- Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Jeremy C Collins
- Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Leonardo M Angelone
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland
| | - Boris Keil
- Department of Life Science Engineering, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Rod S Passman
- Division of Cardiology, Department of Medicine, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Giorgio Bonmassar
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Peter Serano
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland
| | | | - Jim DeLap
- ANSYS Inc., Canonsburg, Pennsylvania
| | - James C Carr
- Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Lawrence L Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
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