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Dankar R, Wehbi J, Refaat MM. The clinical and economic impact of extended battery longevity of the extravascular implantable cardioverter defibrillator. J Cardiovasc Electrophysiol 2024; 35:238-239. [PMID: 38180150 DOI: 10.1111/jce.16174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024]
Affiliation(s)
- Razan Dankar
- Department of Internal Medicine, Division of Cardiology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Jad Wehbi
- Department of Internal Medicine, Division of Cardiology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Marwan M Refaat
- Department of Internal Medicine, Division of Cardiology, American University of Beirut Medical Center, Beirut, Lebanon
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Knight BP, Clémenty N, Amin A, Birgersdotter-Green UM, Roukoz H, Holbrook R, Manlucu J. The clinical and economic impact of extended battery longevity of a substernal extravascular implantable cardioverter defibrillator. J Cardiovasc Electrophysiol 2024; 35:230-237. [PMID: 38047467 DOI: 10.1111/jce.16150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 11/06/2023] [Accepted: 11/23/2023] [Indexed: 12/05/2023]
Abstract
INTRODUCTION The extravascular implantable cardioverter defibrillator (EV ICD) has extended projected battery longevity compared to the subcutaneous implantable cardioverter defibrillator (S-ICD). This study used modeling to characterize the need for generator changes, long-term complications, and overall costs for both the EV ICD and S-ICD in healthcare systems of various countries. METHODS Battery longevity data were modeled using a Markov model from averages reported in device labeling for the S-ICD and with engineering estimates based on real life usage from EV ICD Pivotal Study patient data to introduce variability. Clinical demographic data were derived from published literature. The primary outcomes were defined as the number of generator replacement surgeries, complications, and total healthcare system costs due to battery depletion over the expected lifetime of patients receiving EV ICD or S-ICD therapy. RESULTS Average modeled battery longevity was determined to be 7.3 years for the S-ICD versus 11.8 years for the EV ICD. The probability of a complication after a replacement procedure was 1.4%, with an operative mortality rate of 0.02%. The use of EV ICD was associated with 1.4-1.6 fewer replacements on average over an expected patient lifetime as compared to S-ICD and a 24.3%-26.0% reduction in cost. A one-way sensitivity analysis of the model for the US healthcare system found that use of an EV ICD resulted in a reduction in replacement surgeries of greater than 1 (1.1-1.6) along with five-figure cost savings in all scenarios ($18 602-$40 948). CONCLUSION The longer projected battery life of the EV ICD has the potential to meaningfully reduce long-term morbidity and healthcare resources related to generator changes from the perspective of multiple diverse healthcare systems.
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Affiliation(s)
| | | | - Anish Amin
- Riverside Methodist Hospital, Columbus, Ohio, USA
| | | | - Henri Roukoz
- Cardiology Division, Electrophysiology Section, University of Minnesota, Minneapolis, Minnesota, USA
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Dankar R, Refaat MM. Quality of life and acceptance of the extravascular implantable cardioverter-defibrillator. J Cardiovasc Electrophysiol 2024; 35:247-248. [PMID: 38178582 DOI: 10.1111/jce.16177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024]
Affiliation(s)
- Razan Dankar
- Department of Internal Medicine, Division of Cardiology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Marwan M Refaat
- Department of Internal Medicine, Division of Cardiology, American University of Beirut Medical Center, Beirut, Lebanon
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Chen W, Gong Y, Xia L, Zhang Y, Lu H, Bhatia V, Thompson A, Cao J, Yang J, Yao W, Qiu Z. Characterization of the substernal space with computed tomography imaging in patients with and without median sternotomy: Assessing a novel implant location for extravascular defibrillation lead placement. Pacing Clin Electrophysiol 2023; 46:1066-1072. [PMID: 37504377 DOI: 10.1111/pace.14797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 07/03/2023] [Accepted: 07/16/2023] [Indexed: 07/29/2023]
Abstract
BACKGROUND Implantable cardioverter-defibrillators (ICDs) provide clinically significant therapy for the prevention of sudden cardiac death. This study aimed to characterize the substernal space using computed tomography (CT) in patients with and without prior midline sternotomy to investigate the feasibility of substernal ICD lead implantation in post-sternotomy patients. METHODS High-quality electrocardiogram-gated CT images from 100 patients (71% male, average body mass index 23.5 ± 2.9) were retrospectively collected, including 50 patients with prior midline sternotomy (S-group) and 50 patients with no prior sternotomy (NS-group). Distances were measured from the retrosternal surface to the epicardial surface of the heart and segmented into four regions from the xiphoid tip and superiorly along the sternum. RESULTS Results generally showed a measurable but narrower average sternum-to-heart distance in the prior sternotomy group compared to the non-sternotomy group in all four regions (p < .05). In the S-group, the sternum-to-heart distances across all regions ranged from 0 to 32.0 mm, while in the NS-group, the distances ranged from 0 to 39.9 mm. CONCLUSION Small but measurable separations between the heart and sternum were observed in patients with prior sternotomy, particularly near the xiphoid region, indicating the potential viability of extravascular substernal ICD lead implantation in post-sternotomy patients.
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Affiliation(s)
- Wanlan Chen
- Department of Cardiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Cardiology, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Yongjun Gong
- Department of Radiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Limin Xia
- Department of Cardiovascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yu Zhang
- Department of Cardiology, Huadong Hospital, Fudan University, Shanghai, China
| | - Hongyang Lu
- Cardiac Rhythm Management Research, Medtronic (Shanghai) Ltd., Shanghai, China
| | - Varun Bhatia
- Cardiac Rhythm Management Research, Medtronic, Inc., Mounds View, Minnesota, USA
| | - Amy Thompson
- Cardiac Rhythm Management Research, Medtronic, Inc., Mounds View, Minnesota, USA
| | - Jian Cao
- Cardiac Rhythm Management Research, Medtronic, Inc., Mounds View, Minnesota, USA
| | - Jun Yang
- Department of Radiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weiwu Yao
- Department of Radiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhaohui Qiu
- Department of Cardiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Bressi E, Ellenbogen KA, Kron J. Novel Intercostal Extravascular ICD Lead Compatible With Standard Pulse Generators: Another Step Forward in ICD Evolution? Circ Arrhythm Electrophysiol 2023; 16:433-436. [PMID: 37485681 DOI: 10.1161/circep.123.012256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Affiliation(s)
- Edoardo Bressi
- Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Pauley Heart Center, Richmond (E.B., K.A.E., J.K.)
- Department of Cardiovascular Sciences, Policlinico Casilino of Rome, Italy (E.B.)
| | - Kenneth A Ellenbogen
- Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Pauley Heart Center, Richmond (E.B., K.A.E., J.K.)
| | - Jordana Kron
- Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Pauley Heart Center, Richmond (E.B., K.A.E., J.K.)
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Burke MC, Knops RE, Reddy V, Aasbo J, Husby M, Marcovecchio A, O'Connor M, Sanghera R, Scheck D, Pepplinkhuizen S, Ebner A. Initial Experience With Intercostal Insertion of an Extravascular ICD Lead Compatible With Existing Pulse Generators. Circ Arrhythm Electrophysiol 2023; 16:421-432. [PMID: 37582163 DOI: 10.1161/circep.123.011922] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/20/2023] [Indexed: 08/17/2023]
Abstract
BACKGROUND This study assessed safety and feasibility of a novel extravascular implantable cardioverter defibrillator (ICD) lead when inserted anteriorly through a rib space and connected to various commercially available ICD pulse generators (PGs) placed in either a left mid-axillary or left pectoral pocket. Currently available or investigational, extravascular-ICDs include a subcutaneous or subxiphoid lead connected to customized extravascular-ICD PGs. METHODS This novel extravascular-ICD (AtaCor Medical Inc, San Clemente, CA) employs a unique intercostal implant technique and is designed to function with commercial DF-4 ICD PGs. In this nonrandomized, single-center, acute study, 36 de novo or replacement ICD (transvenous ICD) patients enrolled to receive a concomitant extravascular-ICD lead inserted through an intercostal space along the left parasternal margin. extravascular-ICD leads were connected to DF-4 compatible ICD PGs positioned in either a left mid-axillary or pectoral pocket for acute sensing and defibrillation testing. Defibrillation testing started at 30 Joules (J) and stepped up or down in 5 to 10 joule increments depending on the success and limitations of the generator used. RESULTS Successful acute defibrillation using ≤35 J was noted in 100% of left mid-axillary PG subjects (n=27, mean 16.3±8.6 J) and 83% of left pectoral PG subjects (n=6, mean 21.0±8.4 J). Furthermore, 24 of 27 (89%) of patients tested with a left, mid-axillary intermuscular PG had successful VF conversion with defibrillation energies at least 10 J below the maximum delivered output of the device. All evaluable episodes (n=93) were automatically sensed, detected, and shocked. No serious device-related intraoperative adverse events were observed. CONCLUSIONS This first-in-human study documented the safe and reliable placement of a novel extravascular ICD lead with effective sensing and defibrillation of induced ventricular fibrillation using commercial DF-4 ICD PGs.
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Affiliation(s)
- Martin C Burke
- CorVita Science Foundation, Chicago, IL (M.C.B.)
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, Academic Medical Center, the Netherlands (M.C.B., R.E.K., S.P.)
- AtaCor Medical, Inc., San Clemente, CA (M.C.B., M.H., A.M., M.O., R.S., D.S.)
| | - Reinoud E Knops
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, Academic Medical Center, the Netherlands (M.C.B., R.E.K., S.P.)
| | | | - Johan Aasbo
- Lexington Cardiology and Baptist Health, KY (J.A.)
| | - Michael Husby
- AtaCor Medical, Inc., San Clemente, CA (M.C.B., M.H., A.M., M.O., R.S., D.S.)
| | - Alan Marcovecchio
- AtaCor Medical, Inc., San Clemente, CA (M.C.B., M.H., A.M., M.O., R.S., D.S.)
| | - Mark O'Connor
- AtaCor Medical, Inc., San Clemente, CA (M.C.B., M.H., A.M., M.O., R.S., D.S.)
| | - Rick Sanghera
- AtaCor Medical, Inc., San Clemente, CA (M.C.B., M.H., A.M., M.O., R.S., D.S.)
| | - Don Scheck
- AtaCor Medical, Inc., San Clemente, CA (M.C.B., M.H., A.M., M.O., R.S., D.S.)
| | - Shari Pepplinkhuizen
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, Academic Medical Center, the Netherlands (M.C.B., R.E.K., S.P.)
| | - Adrian Ebner
- Cardiovascular Department, Sanatorio Italiano, Asunción, Paraguay (A.E.)
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Baird JK. African Plasmodium vivax malaria improbably rare or benign. Trends Parasitol 2022:S1471-4922(22)00109-X. [PMID: 35667992 DOI: 10.1016/j.pt.2022.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/10/2022] [Accepted: 05/10/2022] [Indexed: 11/23/2022]
Abstract
The overwhelming dominance of Duffy blood group negativity among most people living in sub-Saharan Africa has been considered the basis of their protection from endemic Plasmodium vivax malaria. New evidence demonstrates widespread transmission of P. vivax in Duffy-negative Africa, though currently of unknown distribution, magnitude, or consequences. Other new evidence from outside of Africa demonstrates marked tropisms of P. vivax for extravascular tissues of bone marrow and spleen. Those establish states of proliferative infection with low-grade or undetectable parasitemia of peripheral blood causing acute and chronic disease. This review examines the plausibility of those infectious processes also operating in Duffy-negative Africans and causing harm of unrecognized origin.
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Thompson AE, Marshall M, Lentz L, Mazzetti H. Three-Year Extraction Experience of a Novel Substernal Extravascular Defibrillation Lead in Sheep. Pacing Clin Electrophysiol 2022; 45:314-322. [PMID: 35048393 PMCID: PMC9302635 DOI: 10.1111/pace.14451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/09/2021] [Accepted: 01/02/2022] [Indexed: 11/28/2022]
Abstract
Background The extravascular implantable cardioverter‐defibrillator (EV ICD) with lead implantation in the substernal space may provide an alternative to transvenous and subcutaneous systems. This is the first‐reported chronic extraction experience for EV ICD leads. The aim of the study is to evaluate the chronic encapsulation and extractability of EV ICD leads. Methods Two EV ICD leads and one transvenous lead were implanted in each of 24 mature sheep. A subset of animals was evaluated yearly for histology and lead extractability. Extractions were performed using simple traction or extraction tools. Histology evaluated the encapsulating tissue. Results At 1 year, extraction was performed successfully for two of five EV ICD leads with traction alone using ≤3.1 kg‐force (kgf) and the remainder extracted successfully with extraction tools; no transvenous leads were removed with traction alone. At 2 years, no EV ICD or transvenous leads were extracted with traction alone, while at 3 years, one of eight EV ICD leads and two of four transvenous leads were extracted with traction (0.8 and ≤2.3 kgf, respectively). There was one observation of hemopericardium resulting in tamponade with EV ICD extraction but without injury to cardiovascular structures and related to the unique implant tract. Among transvenous leads, inversion of the ventricle with loss of cardiac output resulted in abandonment of traction for two animals. Conclusions Chronic extraction of EV ICD leads from the substernal space was successfully performed using traction and simple tools through 3 years in sheep with one observation of hemopericardium that did not originate from cardiovascular injury.
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Crozier I, O'Donnell D, Boersma L, Murgatroyd F, Manlucu J, Knight BP, Birgersdotter-Green UM, Leclercq C, Thompson A, Sawchuk R, Willey S, Wiggenhorn C, Friedman P. The extravascular implantable cardioverter-defibrillator: The pivotal study plan. J Cardiovasc Electrophysiol 2021; 32:2371-2378. [PMID: 34322918 PMCID: PMC9290824 DOI: 10.1111/jce.15190] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/23/2021] [Accepted: 06/08/2021] [Indexed: 11/29/2022]
Abstract
Background Transvenous implantable cardioverter defibrillators (TV ICD) provide life‐saving therapy for millions of patients worldwide. However, they are susceptible to several potential short‐ and long‐ term complications including cardiac perforation and pneumothorax, lead dislodgement, venous obstruction, and infection. The extravascular ICD system's novel design and substernal implant approach avoids the risks associated with TV ICDs while still providing pacing features and similar generator size to TV ICDs. Study Design The EV ICD pivotal study is a prospective, multicenter, single‐arm, nonrandomized, premarket clinical study designed to examine the safety and acute efficacy of the system. This study will enroll up to 400 patients with a Class I or IIa indication for implantation of an ICD. Implanted subjects will be followed up to approximately 3.5 years, depending on when the patient is enrolled. Objective The clinical trial is designed to demonstrate safety and effectiveness of the EV ICD system in human use. The safety endpoint is freedom from major complications, while the efficacy endpoint is defibrillation success. Both endpoints will be assessed against prespecified criteria. Additionally, this study will evaluate antitachycardia pacing performance, electrical performance, extracardiac pacing sensation, asystole pacing, appropriate and inappropriate shocks, as well as a summary of adverse events. Conclusion The EV ICD pivotal study is designed to provide clear evidence addressing the safety and efficacy performance of the EV ICD System.
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Affiliation(s)
- Ian Crozier
- Department of Cardiology, Christchurch Hospital, Christchurch, New Zealand
| | - David O'Donnell
- Department of Cardiology, Austin Health, Heidelberg, Victoria, Australia
| | - Lucas Boersma
- Department of Cardiology, St. Antonius Hospital Nieuwegein and Amsterdam UMC, Amsterdam, Netherlands
| | | | - Jaimie Manlucu
- Division of Cardiology, London Health Sciences Centre, London, Ontario, Canada
| | - Bradley P Knight
- Division of Cardiology, Northwestern University, Chicago, Illinois, USA
| | | | - Christophe Leclercq
- Department of Cardiology, CHU de Rennes-Hôpital Pontchaillou France, Rennes, France
| | - Amy Thompson
- Department of Cardiac Rhythm, Medtronic plc, Mounds View, Minnesota, USA
| | - Robert Sawchuk
- Department of Cardiac Rhythm, Medtronic plc, Mounds View, Minnesota, USA
| | - Sarah Willey
- Department of Cardiac Rhythm, Medtronic plc, Mounds View, Minnesota, USA
| | | | - Paul Friedman
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
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Swerdlow CD, Zhang X, Sawchuk R, Greenhut S, Grinberg Y, Liu Y, Crozier I, O'Donnell D, Kotschet E, Haqqani H. Design and Preliminary Results of Sensing and Detection for an Extravascular Implantable Cardioverter-Defibrillator. JACC Clin Electrophysiol 2021:S2405-500X(21)00215-2. [PMID: 33933410 DOI: 10.1016/j.jacep.2021.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/03/2021] [Accepted: 03/03/2021] [Indexed: 11/22/2022]
Abstract
OBJECTIVES This study reports the sensing and arrhythmia detection performance of a novel extravascular (EV) implantable cardioverter-defibrillator (ICD) in a first-in-human pilot study. BACKGROUND The EV ICD lead is implanted in the substernal space, resulting in novel sensing and detection challenges. It uses a programmable sensing profile with new or modified discrimination of oversensing and of ventricular tachycardia (VT) from supraventricular tachycardia (SVT). METHODS Electrograms were post-processed from induced ventricular fibrillation (VF) at implant to determine virtual detection times for each programmable sensitivity and the least-sensitive safe sensitivity setting. In ambulatory patients, programmed sensitivity provided at least a twofold safety margin for detecting induced VF. Noise discrimination was stress tested, and the effects of source, posture, and lead maturation were determined on electrogram amplitude. Telemetry Holter monitors were used to quantify undersensing and oversensing. RESULTS In 20 patients at implant, the least-sensitive safe sensitivity for VF detection ranged from 0.1 to 0.6 mV. Seventeen patients were followed up for a total of 16.6 patient-years. Electrogram amplitudes were stable over time, but there were significant differences among postures and sensing vectors. For the primary sensing vector, the weighted oversensing and undersensing rates were 1.03% and 0.40% respectively, on a beat-to-beat basis. Oversensing did not cause inappropriate therapy in patients with in situ leads. Oversensing discriminators withheld VF detection in 4 of 5 spontaneous, sustained oversensed episodes. SVT-VT discriminators correctly classified 93% of 128 sustained SVTs in monitor zones. CONCLUSIONS In the EV ICD pilot study, oversensing did not cause inappropriate therapy during ambulatory follow-up of stable leads.
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Cheng Y, van Zijl PCM, Hua J. Measurement of parenchymal extravascular R2* and tissue oxygen extraction fraction using multi-echo vascular space occupancy MRI at 7 T. NMR Biomed 2015; 28:264-271. [PMID: 25521948 PMCID: PMC4297270 DOI: 10.1002/nbm.3250] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 11/19/2014] [Accepted: 11/26/2014] [Indexed: 06/04/2023]
Abstract
Parenchymal extravascular R2* is an important parameter for quantitative blood oxygenation level-dependent (BOLD) studies. Total and intravascular R2* values and changes in R2* values during functional stimulations have been reported in a number of studies. The purpose of this study was to measure absolute extravascular R2* values in human visual cortex and to estimate the intra- and extravascular contributions to the BOLD effect at 7 T. Vascular space occupancy (VASO) MRI was employed to separate out the extravascular tissue signal. Multi-echo VASO and BOLD functional MRI (fMRI) with visual stimulation were performed at 7 T for R2* measurement at a spatial resolution of 2.5 × 2.5 × 2.5 mm(3) in healthy volunteers (n = 6). The ratio of changes in extravascular and total R2* (ΔR2*) was used to estimate the extravascular fraction of the BOLD effect. Extravascular R2* values were found to be 44.66 ± 1.55 and 43.38 ± 1.51 s(-1) (mean ± standard error of the mean, n = 6) at rest and activation, respectively, in human visual cortex at 7 T. The extravascular BOLD fraction was estimated to be 91 ± 3%. The parenchymal oxygen extraction fraction (OEF) during activation was estimated to be 0.24 ± 0.01 based on the R2* measurements, indicating an approximately 37% decrease compared with OEF at rest.
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Affiliation(s)
- Ying Cheng
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Peter C. M. van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD USA
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Jun Hua
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD USA
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD USA
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