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Amrami KK, Chebrolu VV, Felmlee JP, Frick MA, Powell GM, Marek T, Howe BM, Fagan AJ, Kollasch PD, Spinner RJ. 7T for clinical imaging of benign peripheral nerve tumors: preliminary results. Acta Neurochir (Wien) 2023; 165:3549-3558. [PMID: 37464202 DOI: 10.1007/s00701-023-05724-1] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 07/07/2023] [Indexed: 07/20/2023]
Abstract
PURPOSE MRI has become an essential diagnostic imaging modality for peripheral nerve pathology. Early MR imaging for peripheral nerve depended on inferred nerve involvement by visualizing downstream effects such as denervation muscular atrophy; improvements in MRI technology have made possible direct visualization of the nerves. In this paper, we share our early clinical experience with 7T for benign neurogenic tumors. MATERIALS Patients with benign neurogenic tumors and 7T MRI examinations available were reviewed. Cases of individual benign peripheral nerve tumors were included to demonstrate 7T MRI imaging characteristics. All exams were performed on a 7T MRI MAGNETOM Terra using a 28-channel receive, single-channel transmit knee coil. RESULTS Five cases of four pathologies were selected from 38 patients to depict characteristic imaging features in different benign nerve tumors and lesions using 7T MRI. CONCLUSION The primary advantage of 7T over 3T is an increase in signal-to-noise ratio which allows higher in plane resolution so that the smallest neural structures can be seen and characterized. This improvement in MR imaging provides the opportunity for more accurate diagnosis and surgical planning in selected cases. As this technology continues to evolve for clinical purposes, we anticipate increasing applications and improved patient care using 7T MRI for the diagnosis of peripheral nerve masses.
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Affiliation(s)
- Kimberly K Amrami
- Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA.
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA.
| | - Venkata V Chebrolu
- Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
- Siemens Healthineers, Rochester, MN, USA
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Matthew A Frick
- Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Garret M Powell
- Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Tomas Marek
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
- First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Benjamin M Howe
- Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Andrew J Fagan
- Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Peter D Kollasch
- Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
- Siemens Healthineers, Rochester, MN, USA
| | - Robert J Spinner
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
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Thompson SM, Gorny KR, Koepsel EMK, Welch BT, Mynderse L, Lu A, Favazza CP, Felmlee JP, Woodrum DA. Body Interventional MRI for Diagnostic and Interventional Radiologists: Current Practice and Future Prospects. Radiographics 2021; 41:1785-1801. [PMID: 34597216 DOI: 10.1148/rg.2021210040] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Clinical use of MRI for guidance during interventional procedures emerged shortly after the introduction of clinical diagnostic MRI in the late 1980s. However, early applications of interventional MRI (iMRI) were limited owing to the lack of dedicated iMRI magnets, pulse sequences, and equipment. During the 3 decades that followed, technologic advancements in iMRI magnets that balance bore access and field strength, combined with the development of rapid MRI pulse sequences, surface coils, and commercially available MR-conditional devices, led to the rapid expansion of clinical iMRI applications, particularly in the field of body iMRI. iMRI offers several advantages, including superior soft-tissue resolution, ease of multiplanar imaging, lack of ionizing radiation, and capability to re-image the same section. Disadvantages include longer examination times, lack of MR-conditional equipment, less operator familiarity, and increased cost. Nonetheless, MRI guidance is particularly advantageous when the disease is best visualized with MRI and/or when superior soft-tissue contrast is needed for treatment monitoring. Safety in the iMRI environment is paramount and requires close collaboration among interventional radiologists, MR physicists, and all other iMRI team members. The implementation of risk-limiting measures for personnel and equipment in MR zones III and IV is key. Various commercially available MR-conditional needles, wires, and biopsy and ablation devices are now available throughout the world, depending on the local regulatory status. As such, there has been tremendous growth in the clinical applications of body iMRI, including localization of difficult lesions, biopsy, sclerotherapy, and cryoablation and thermal ablation of malignant and nonmalignant soft-tissue neoplasms. Online supplemental material is available for this article. ©RSNA, 2021.
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Affiliation(s)
- Scott M Thompson
- From the Department of Radiology (S.M.T., K.R.G., E.M.K.K., B.T.W., A.L., C.P.F., J.P.F., D.A.W.), Division of Vascular and Interventional Radiology (S.M.T.), and Department of Urology (L.M.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905
| | - Krzysztof R Gorny
- From the Department of Radiology (S.M.T., K.R.G., E.M.K.K., B.T.W., A.L., C.P.F., J.P.F., D.A.W.), Division of Vascular and Interventional Radiology (S.M.T.), and Department of Urology (L.M.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905
| | - Erica M Knavel Koepsel
- From the Department of Radiology (S.M.T., K.R.G., E.M.K.K., B.T.W., A.L., C.P.F., J.P.F., D.A.W.), Division of Vascular and Interventional Radiology (S.M.T.), and Department of Urology (L.M.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905
| | - Brian T Welch
- From the Department of Radiology (S.M.T., K.R.G., E.M.K.K., B.T.W., A.L., C.P.F., J.P.F., D.A.W.), Division of Vascular and Interventional Radiology (S.M.T.), and Department of Urology (L.M.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905
| | - Lance Mynderse
- From the Department of Radiology (S.M.T., K.R.G., E.M.K.K., B.T.W., A.L., C.P.F., J.P.F., D.A.W.), Division of Vascular and Interventional Radiology (S.M.T.), and Department of Urology (L.M.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905
| | - Aiming Lu
- From the Department of Radiology (S.M.T., K.R.G., E.M.K.K., B.T.W., A.L., C.P.F., J.P.F., D.A.W.), Division of Vascular and Interventional Radiology (S.M.T.), and Department of Urology (L.M.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905
| | - Christopher P Favazza
- From the Department of Radiology (S.M.T., K.R.G., E.M.K.K., B.T.W., A.L., C.P.F., J.P.F., D.A.W.), Division of Vascular and Interventional Radiology (S.M.T.), and Department of Urology (L.M.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905
| | - Joel P Felmlee
- From the Department of Radiology (S.M.T., K.R.G., E.M.K.K., B.T.W., A.L., C.P.F., J.P.F., D.A.W.), Division of Vascular and Interventional Radiology (S.M.T.), and Department of Urology (L.M.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905
| | - David A Woodrum
- From the Department of Radiology (S.M.T., K.R.G., E.M.K.K., B.T.W., A.L., C.P.F., J.P.F., D.A.W.), Division of Vascular and Interventional Radiology (S.M.T.), and Department of Urology (L.M.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905
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3
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Gibson WS, Rusheen AE, Oh Y, In MH, Gorny KR, Felmlee JP, Klassen BT, Jung SJ, Min HK, Lee KH, Jo HJ. Symptom-specific differential motor network modulation by deep brain stimulation in Parkinson's disease. J Neurosurg 2021:1-9. [PMID: 33990083 DOI: 10.3171/2020.10.jns202277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/06/2020] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an established neurosurgical treatment for the motor symptoms of Parkinson's disease (PD). While often highly effective, DBS does not always yield optimal therapeutic outcomes, and stimulation-induced adverse effects, including paresthesia, muscle contractions, and nausea/lightheadedness, commonly occur and can limit the efficacy of stimulation. Currently, objective metrics do not exist for monitoring neural changes associated with stimulation-induced therapeutic and adverse effects. METHODS In the present study, the authors combined intraoperative functional MRI (fMRI) with STN DBS in 20 patients with PD to test the hypothesis that stimulation-induced blood oxygen level-dependent signals contained predictive information concerning the therapeutic and adverse effects of stimulation. RESULTS As expected, DBS resulted in blood oxygen level-dependent activation in myriad motor regions, including the primary motor cortex, caudate, putamen, thalamus, midbrain, and cerebellum. Across the patients, DBS-induced improvements in contralateral Unified Parkinson's Disease Rating Scale tremor subscores correlated with activation of thalamic, brainstem, and cerebellar regions. In addition, improvements in rigidity and bradykinesia subscores correlated with activation of the primary motor cortex. Finally, activation of specific sensorimotor-related subregions correlated with the presence of DBS-induced adverse effects, including paresthesia and nausea (cerebellar cortex, sensorimotor cortex) and unwanted muscle contractions (caudate and putamen). CONCLUSIONS These results suggest that DBS-induced activation patterns revealed by fMRI contain predictive information with respect to the therapeutic and adverse effects of DBS. The use of fMRI in combination with DBS therefore may hold translational potential to guide and improve clinical stimulator optimization in patients.
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Affiliation(s)
- William S Gibson
- Departments of1Neurologic Surgery.,2Department of Neurological Surgery, Northwestern University, Evanston, Illinois; and
| | - Aaron E Rusheen
- Departments of1Neurologic Surgery.,3Medical Scientist Training Program, Mayo Clinic, Rochester, Minnesota
| | - Yoonbae Oh
- Departments of1Neurologic Surgery.,4Biomedical Engineering
| | | | | | | | | | - Sung Jun Jung
- 7Department of Physiology, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | | | - Kendall H Lee
- Departments of1Neurologic Surgery.,4Biomedical Engineering
| | - Hang Joon Jo
- Departments of1Neurologic Surgery.,5Radiology, and.,6Neurology, and.,7Department of Physiology, College of Medicine, Hanyang University, Seoul, Republic of Korea
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4
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Lobo R, Edmonson HA, Donato L, Friedman P, Wockenfus AM, Cha YM, McGee KP, Felmlee JP, Watson R, Jaffe A. LACK OF MYOCARDIAL INJURY AFTER MAGNETIC RESONANCE IMAGING IN PATIENTS WITH CONDITIONAL AND NON-CONDITIONAL CARDIAC IMPLANTABLE ELECTRONIC DEVICES -A HIGH SENSITIVITY TROPONIN EVALUATION. J Am Coll Cardiol 2021. [DOI: 10.1016/s0735-1097(21)01659-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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5
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Lu A, Favazza CP, Felmlee JP, Welch BT, Mynderse LA, Browne JE, Woodrum DA, Gorny KR. Experimental Investigation of Cryoneedle Heating during MR-Guided Cryoablation in Ex Vivo Tissue Samples at 1.5-Tesla. J Vasc Interv Radiol 2021; 32:721-728.e2. [PMID: 33663924 DOI: 10.1016/j.jvir.2021.01.272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/07/2021] [Accepted: 01/22/2021] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To investigate cryoneedle heating risks during magnetic resonance (MR)-guided cryoablation and potential strategies to mitigate these risks. MATERIALS AND METHODS Ex vivo experiments were performed on a 1.5-Tesla (T) MR scanner using an MR conditional cryoablation system on porcine tissue phantoms. Cryoneedles were placed inside the tissue phantom either with or without an angiocatheter. Typical cryoneedle geometric configurations (including gas supply line) encountered in clinical procedures with low to high expected heating risks were investigated. Up to 4 fiber optic temperature sensors were attached to the cryoneedle/angiocatheter to measure the MR-induced cryoneedle heating at different locations during MR with different estimated specific absorption rates (SARs). The impact of cryoneedle heating on cryoablation treatment was studied by comparing temperature changes during 10-min freeze-thaw cycles with and without MR. RESULTS Rapid temperature increases of >100 °C in < 2 minutes were observed during MR with a SAR of 2.1 W/kg. The temperature changes during a typical freeze-thaw cycle were also affected by cryoneedle heating when MR was used to monitor the ice-ball evolution. The observed cryoneedle heating was affected by multiple factors; including cryoneedle geometric configurations, sequence SAR, whether an angiocatheter was used, and whether the cryoneedle was connected to the rest of the cryoablation system. CONCLUSIONS The ex vivo experiments demonstrated that MR could induce significant cryoneedle heating risks. Furthermore, MR-induced cryoneedle heating can affect temperatures in the ice-ball evolution during the freeze-thaw cycle. Several practical strategies to reduce the cryoneedle heating have been proposed.
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Affiliation(s)
- Aiming Lu
- Department of Radiology, Mayo Clinic, Rochester, Minnesota.
| | | | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | - Brian T Welch
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | - Lance A Mynderse
- Department of Radiology, Mayo Clinic, Rochester, Minnesota; Department of Urology, Mayo Clinic, Rochester, Minnesota
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6
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Long Z, Kurup AN, Jensen NM, Hangiandreou NJ, Schueler BA, Yu L, Leng S, Wood CP, Felmlee JP. Initial testing of pegfilgrastim (Neulasta Onpro) on-body injector in multiple radiological imaging environments. J Appl Clin Med Phys 2021; 22:343-349. [PMID: 33395503 PMCID: PMC7856482 DOI: 10.1002/acm2.13156] [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] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 12/07/2020] [Accepted: 12/12/2020] [Indexed: 11/15/2022] Open
Abstract
Purpose An increasing number of implantable or external devices can impact whether patients can receive radiological imaging examinations. This study examines and tests the Neulasta (pegfilgrastim) Onpro on‐body injector in multiple imaging environments. Methods The injector was analyzed for four imaging modalities with testing protocols and strategies developed for each modality. In x‐ray and computed tomography (CT), scans with much higher exposure than clinical protocols were performed with the device attached to an anthropomorphic phantom. The device was monitored until the completion of drug delivery. For magnetic resonance imaging (MRI), the device was assessed using a hand‐held magnet and underwent the magnetically induced displacement testing in a 1.5T clinical MRI scanner room. For ultrasound, magnetic field changes were measured around an ultrasound scanner system with three transducers. Results For x‐ray and CT no sign of device error was identified during or after the high radiation exposure scans. Drug delivery was completed at expected timing with expected volume. For MRI the device showed significant attractive force towards the hand‐held magnet and a 50‐degree deflection angle at 50 cm from the opening of the scanner bore. No further assessment from the gradient or radiofrequency field was deemed necessary. For ultrasound the maximum magnetic field change from baseline was measured to be +11.7 μT in comparison to +74.2 μT at 4 inches from a working microwave. Conclusions No device performance issue was identified under the extreme test conditions in x‐ray or CT. The device was found to be MR Unsafe. Magnetic field changes around an ultrasound system met the limitation set by manufacture. Patient ultrasound scanning is considered safe as long as the transducers do not inadvertently loosen the device.
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Affiliation(s)
- Zaiyang Long
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | | | | | | | - Lifeng Yu
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Shuai Leng
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
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7
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Fagan AJ, Jacobs PS, Hulshizer TC, Rossman PJ, Frick MA, Amrami KK, Felmlee JP. 7T MR Thermometry technique for validation of system-predicted SAR with a home-built radiofrequency wrist coil. Med Phys 2020; 48:781-790. [PMID: 33294999 DOI: 10.1002/mp.14641] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/03/2020] [Accepted: 11/30/2020] [Indexed: 11/12/2022] Open
Abstract
PURPOSE A 7T magnetic resonance thermometry (MRT) technique was developed to validate the conversion factor between the system-measured transmitted radiofrequency (RF) power into a home-built RF wrist coil with the system-predicted SAR value. The conversion factor for a new RF coil developed for ultra high magnetic field MRI systems is used to ensure that regulatory limits on RF energy deposition in tissue, specifically the local 10g-averaged specific absorption rate (SAR10g ), are not exceeded. MRT can be used to validate this factor by ensuring that MRT-measured SAR values do not exceed those predicted by the system. METHODS A 14-cm diameter high-pass birdcage RF coil was built to image the wrist at 7T. A high spatial and temporal resolution dual-echo gradient echo MRT technique, incorporating quasi-simultaneous RF-induced heating and temperature change measurements using the proton resonance frequency method, was developed. The technique allowed for high-temperature resolution measurements (~±0.1°C) to be performed every 20 s over a 4-min heating period, with high spatial resolution (2.56 mm3 voxel size) and avoiding phase discontinuities arising from severe magnetic susceptibility-induced B0 inhomogeneities. Magnetic resonance thermometry was performed on a phantom made from polyvinylpyrrolidone to mimic the dielectric properties of muscle tissue at 297.2 MHz. Temperature changes measured with MRT and four fiber optic temperature sensors embedded in the phantom were compared. Electromagnetic simulations of the coil and phantom were developed and validated via comparison of simulated and measured B1 + maps in the phantom. The position of maximum SAR within the coil was determined from simulations, and MRT was performed within a wrist-sized piece of meat positioned at that SAR hotspot location. MRT-measured and system-predicted SAR values for the phantom and meat were compared. RESULTS Temperature change measurements from MRT matched closely to those from the fiber optic temperature sensors. The simulations were validated via close correlation between the simulated and MRT-measured B1 + and SAR maps. Using a coil conversion factor of 2 kg-1 , MRT-measured point-SAR values did not exceed the system-predicted SAR10g in either the uniform phantom or in the piece of meat mimicking the wrist located at the SAR hotspot location. CONCLUSIONS A highly accurate MRT technique with high spatial and temporal resolution was developed. This technique can be used to ensure that system-predicted SAR values are not exceeded in practice, thereby providing independent validation of SAR levels delivered by a newly built RF wrist coil. The MRT technique is readily generalizable to perform safety evaluations for other RF coils at 7T.
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Affiliation(s)
- Andrew J Fagan
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Paul S Jacobs
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Thomas C Hulshizer
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Phillip J Rossman
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Matthew A Frick
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Kimberly K Amrami
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
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Abstract
The arrival of 7T MR imaging into the clinic represents a significant step-change in MR technology. This article describes safety concerns associated with imaging at 7T, including the increased magnetic forces on magnetic objects at 7T and the interaction of the 300 MHz (Larmor) radiofrequency energy with tissue in the body. A dedicated multidisciplinary 7T Safety team should develop safety policies and procedures to address these safety challenges and keep abreast of best practice in the field. The off-label imaging of implanted devices is discussed, and also the need for staff training to deal with complexities of patient handling and image interpretation.
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Affiliation(s)
- Andrew J Fagan
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA.
| | - Kimberly K Amrami
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Kirk M Welker
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Matthew A Frick
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Robert E Watson
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA
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9
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Lee C, Bhatt A, Felmlee JP, Trester P, Lanners D, Paulsen A, Brunette J. How to Safely Perform Magnetic Resonance Imaging-guided Radioactive Seed Localizations in the Breast. J Clin Imaging Sci 2020; 10:19. [PMID: 32363081 PMCID: PMC7193148 DOI: 10.25259/jcis_11_2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 03/25/2020] [Indexed: 11/17/2022] Open
Abstract
When a breast lesion is seen on only magnetic resonance imaging (MRI) and needs to be excised, pre-operative MRI-guided radioactive seed localization (RSL) is preferred. However, MRI safety and radiation safety issues associated with the inability to recover a potentially lost seed in the MRI scanner room (Zone IV) have precluded this in the past. This manuscript provides a protocol for MRI-guided RSLs that meets MRI safety and radiation safety criteria established by the American College of Radiology and the Nuclear Regulatory Commission. To the authors’ best knowledge, this has never been published in the literature. The complete protocol is provided.
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Affiliation(s)
| | - Asha Bhatt
- Department of Radiology, Mayo Clinic, United States
| | | | | | | | - Andrew Paulsen
- Radiopharmaceutical Laboratory, Mayo Clinic, United States
| | - Jeffrey Brunette
- Radiation Safety, Mayo Clinic, Rochester, Minnesota, United States
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10
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Lu A, Woodrum DA, Felmlee JP, Favazza CP, Gorny KR. Improved MR-thermometry during hepatic microwave ablation by correcting for intermittent electromagnetic interference artifacts. Phys Med 2020; 71:100-107. [PMID: 32114323 DOI: 10.1016/j.ejmp.2020.02.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/01/2020] [Accepted: 02/19/2020] [Indexed: 12/22/2022] Open
Abstract
MRI-guided microwave ablation (MWA) is a minimally invasive treatment for localized cancer. MR thermometry has been shown to be able to provide vital information for monitoring the procedure in real-time. However, MRI during active MWA can suffer from image quality degradation due to intermittent electromagnetic interference (EMI). A novel approach to correct for EMI-contaminated images is presented here to improve MR thermometry during clinical hepatic MWA. The method was applied to MR-thermometry images acquired during four MR-guided hepatic MWA treatments using a commercially available MRI-configured microwave generator system. During the treatments MR thermometry data acquisition was synchronized to respiratory cycle to minimize the impact of motion. EMI was detected and corrected using uncontaminated k-space data from nearby frames in k-space. Substantially improved temperature and thermal damage maps have been obtained and the treatment zone can be better visualized. Our ex vivo tissue sample study shows the correction introduced minimal errors to the temperature maps and thermal damage maps.
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Affiliation(s)
- Aiming Lu
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, United States.
| | - David A Woodrum
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, United States
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, United States
| | | | - Krzysztof R Gorny
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, United States
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Padmanabhan D, Kella DK, Deshmukh AJ, Mulpuru SK, Mehta RA, Dalzell CM, Olson NE, Felmlee JP, Jondal ML, Asirvatham SJ, Watson RE, Cha YM, Friedman PA. Safety of thoracic magnetic resonance imaging for patients with pacemakers and defibrillators. Heart Rhythm 2019; 16:1645-1651. [DOI: 10.1016/j.hrthm.2019.05.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Indexed: 12/26/2022]
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12
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Watson RE, Walsh SM, Felmlee JP, Friedman PA, Keene MN. Augmenting MRI Safety Screening Processes: Reliable Identification of Cardiac Implantable Electronic Devices by a Ferromagnetic Detector System. J Magn Reson Imaging 2019; 49:e297-e299. [DOI: 10.1002/jmri.26277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 07/15/2018] [Accepted: 07/16/2018] [Indexed: 11/07/2022] Open
Affiliation(s)
| | - Suson M. Walsh
- Department of RadiologyMayo Clinic Rochester Minnesota USA
| | | | - Paul A. Friedman
- Department of Cardiovascular DiseasesMayo Clinic Rochester Minnesota USA
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13
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Chebrolu VV, Kollasch PD, Deshpande V, Grinstead J, Howe BM, Frick MA, Fagan AJ, Benner T, Heidemann RM, Felmlee JP, Amrami KK. Uniform combined reconstruction of multichannel 7T knee MRI receive coil data without the use of a reference scan. J Magn Reson Imaging 2019; 50:1534-1544. [PMID: 30779475 DOI: 10.1002/jmri.26691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/07/2019] [Accepted: 02/07/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND MR image intensity nonuniformity is often observed at 7T. Reference scans from the body coil used for uniformity correction at lower field strengths are typically not available at 7T. PURPOSE To evaluate the efficacy of a novel algorithm, Uniform Combined Reconstruction (UNICORN), to correct receive coil-induced nonuniformity in musculoskeletal 7T MRI without the use of a reference scan. STUDY TYPE Retrospective image analysis study. SUBJECTS MRI data of 20 subjects was retrospectively processed offline. Field Strength/Sequence: Knees of 20 subjects were imaged at 7T with a single-channel transmit, 28-channel phased-array receive knee coil. A turbo-spin-echo sequence was used to acquire 33 series of images. ASSESSMENT Three fellowship-trained musculoskeletal radiologists with cumulative experience of 42 years reviewed the images. The uniformity, contrast, signal-to-noise ratio (SNR), and overall image quality were evaluated for images with no postprocessing, images processed with N4 bias field correction algorithm, and the UNICORN algorithm. STATISTICAL TESTS Intraclass correlation coefficient (ICC) was used for measuring the interrater reliability. ICC and 95% confidence intervals (CIs) were calculated using the R statistical package employing a two-way mixed-effects model based on a mean rating (k = 3) for absolute agreement. The Wilcoxon signed-rank test with continuity correction was used for analyzing the overall image quality scores. RESULTS UNICORN was preferred among the three methods evaluated for uniformity in 97.9% of the pooled ratings, with excellent interrater agreement (ICC of 0.98, CI 0.97-0.99). UNICORN was also rated better than N4 for contrast and equivalent to N4 in SNR with ICCs of 0.80 (CI 0.72-0.86) and 0.67 (CI 0.54-0.77), respectively. The overall image quality scores for UNICORN were significantly higher than N4 (P < 6 × 10-13 ), with good to excellent interrater agreement (ICC 0.90, CI 0.86-0.93). DATA CONCLUSION Without the use of a reference scan, UNICORN provides better image uniformity, contrast, and overall image quality at 7T compared with the N4 bias field-correction algorithm. LEVEL OF EVIDENCE 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1534-1544.
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Affiliation(s)
| | | | | | | | - Benjamin M Howe
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Matthew A Frick
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Andrew J Fagan
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | | | | | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
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14
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Maus TP, Felmlee JP, Unger MD, Beutler AS. MRI guidance technology development in a large animal model for hyperlocal analgesics delivery to the epidural space and dorsal root ganglion. J Neurosci Methods 2018; 312:182-186. [PMID: 30513305 DOI: 10.1016/j.jneumeth.2018.11.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Development of new analgesic drugs or gene therapy vectors for spinal delivery will be facilitated by "hyperlocal" targeting of small therapeutic injectate volumes if spine imaging technology can be used that is ready for future clinical translation. NEW METHOD This study provides methods for MRI-guided drug delivery to the periganglionic epidural space and the dorsal root ganglion (DRG) in the Yucatan swine. RESULTS Phantom studies showed artifact-corrected needle localization with frequency encoding parallel to the needle shaft, while maximizing bandwidth (125 KHz) minimized needle artifact. A custom constructed 8-12 element surface coil (phased array) wrapped over the spine in conjunction with lateral recumbent positioning achieved diagnostic quality signal to noise ratio at the depth of the DRG and afforded transforaminal access via anterolateral or posterolateral vectors, as well as interlaminar access. Swine epidural anatomy was homologous with human anatomy. Injectate containing 2% gadolinium allowed imaging of injectate volumes in increments as small as 10 microliters and discrimination of epidural flow from intraparenchymal injectate delivery into a DRG. All technical and technological elements of the procedure appear clinically translatable. COMPARISON WITH EXISTING METHODS Computed tomographic or fluoroscopic guidance cannot directly visualize drug delivery into the DRG due to contrast medium toxicity, nor reliably identify epidural injection volumes of < 50 microliters. CONCLUSIONS MRI-guided hyperlocal delivery in swine provides a translatable and faithful model of future human spinal novel drug- or gene therapy vector delivery.
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Affiliation(s)
- Timothy P Maus
- Department of Radiology, Mayo Graduate School, Mayo Clinic, Rochester, MN, 55902, USA.
| | - Joel P Felmlee
- Department of Radiology, Mayo Graduate School, Mayo Clinic, Rochester, MN, 55902, USA
| | - Mark D Unger
- Department of Anesthesiology, Mayo Graduate School, Mayo Clinic, Rochester, MN, 55902, USA; Department of Oncology, Mayo Clinic, Mayo Graduate School, Mayo Clinic, Rochester, MN, 55902, USA; Translational Science Track, Mayo Graduate School, Mayo Clinic, Rochester, MN, 55902, USA
| | - Andreas S Beutler
- Department of Anesthesiology, Mayo Graduate School, Mayo Clinic, Rochester, MN, 55902, USA; Department of Oncology, Mayo Clinic, Mayo Graduate School, Mayo Clinic, Rochester, MN, 55902, USA; Translational Science Track, Mayo Graduate School, Mayo Clinic, Rochester, MN, 55902, USA.
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15
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Grewal SS, Zimmerman RS, Worrell G, Brinkmann BH, Tatum WO, Crepeau AZ, Woodrum DA, Gorny KR, Felmlee JP, Watson RE, Hoxworth JM, Gupta V, Vibhute P, Trenerry MR, Kaufmann TJ, Marsh WR, Wharen RE, Van Gompel JJ. Laser ablation for mesial temporal epilepsy: a multi-site, single institutional series. J Neurosurg 2018; 130:1-8. [PMID: 29979119 DOI: 10.3171/2018.2.jns171873] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 02/16/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVEAlthough it is still early in its application, laser interstitial thermal therapy (LiTT) has increasingly been employed as a surgical option for patients with mesial temporal lobe epilepsy. This study aimed to describe mesial temporal lobe ablation volumes and seizure outcomes following LiTT across the Mayo Clinic's 3 epilepsy surgery centers.METHODSThis was a multi-site, single-institution, retrospective review of seizure outcomes and ablation volumes following LiTT for medically intractable mesial temporal lobe epilepsy between October 2011 and October 2015. Pre-ablation and post-ablation follow-up volumes of the hippocampus were measured using FreeSurfer, and the volume of ablated tissue was also measured on intraoperative MRI using a supervised spline-based edge detection algorithm. To determine seizure outcomes, results were compared between those patients who were seizure free and those who continued to experience seizures.RESULTSThere were 23 patients who underwent mesial temporal LiTT within the study period. Fifteen patients (65%) had left-sided procedures. The median follow-up was 34 months (range 12-70 months). The mean ablation volume was 6888 mm3. Median hippocampal ablation was 65%, with a median amygdala ablation of 43%. At last follow-up, 11 (48%) of these patients were seizure free. There was no correlation between ablation volume and seizure freedom (p = 0.69). There was also no correlation between percent ablation of the amygdala (p = 0.28) or hippocampus (p = 0.82) and seizure outcomes. Twelve patients underwent formal testing with computational visual fields. Visual field changes were seen in 67% of patients who underwent testing. Comparing the 5 patients with clinically noticeable visual field deficits to the rest of the cohort showed no significant difference in ablation volume between those patients with visual field deficits and those without (p = 0.94). There were 11 patients with follow-up neuropsychological testing. Within this group, verbal learning retention was 76% in the patients with left-sided procedures and 89% in those with right-sided procedures.CONCLUSIONSIn this study, there was no significant correlation between the ablation volume after LiTT and seizure outcomes. Visual field deficits were common in formally tested patients, much as in patients treated with open temporal lobectomy. Further studies are required to determine the role of amygdalohippocampal ablation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Vivek Gupta
- 9Radiology, Mayo Clinic, Jacksonville, Florida
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16
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Jo HJ, McCairn KW, Gibson WS, Testini P, Zhao CZ, Gorny KR, Felmlee JP, Welker KM, Blaha CD, Klassen BT, Min HK, Lee KH. Global network modulation during thalamic stimulation for Tourette syndrome. Neuroimage Clin 2018; 18:502-509. [PMID: 29560306 PMCID: PMC5857897 DOI: 10.1016/j.nicl.2018.02.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 02/09/2018] [Accepted: 02/18/2018] [Indexed: 12/14/2022]
Abstract
Background and objectives Deep brain stimulation (DBS) of the thalamus is a promising therapeutic alternative for treating medically refractory Tourette syndrome (TS). However, few human studies have examined its mechanism of action. Therefore, the networks that mediate the therapeutic effects of thalamic DBS remain poorly understood. Methods Five participants diagnosed with severe medically refractory TS underwent bilateral thalamic DBS stereotactic surgery. Intraoperative fMRI characterized the blood oxygen level-dependent (BOLD) response evoked by thalamic DBS and determined whether the therapeutic effectiveness of thalamic DBS, as assessed using the Modified Rush Video Rating Scale test, would correlate with evoked BOLD responses in motor and limbic cortical and subcortical regions. Results Our results reveal that thalamic stimulation in TS participants has wide-ranging effects that impact the frontostriatal, limbic, and motor networks. Thalamic stimulation induced suppression of motor and insula networks correlated with motor tic reduction, while suppression of frontal and parietal networks correlated with vocal tic reduction. These regions mapped closely to major regions of interest (ROI) identified in a nonhuman primate model of TS. Conclusions Overall, these findings suggest that a critical factor in TS treatment should involve modulation of both frontostriatal and motor networks, rather than be treated as a focal disorder of the brain. Using the novel combination of DBS-evoked tic reduction and fMRI in human subjects, we provide new insights into the basal ganglia-cerebellar-thalamo-cortical network-level mechanisms that influence the effects of thalamic DBS. Future translational research should identify whether these network changes are cause or effect of TS symptoms.
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Affiliation(s)
- Hang Joon Jo
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA; Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Kevin W McCairn
- Systems Neuroscience Section, Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - William S Gibson
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Paola Testini
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Cong Zhi Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA
| | - Kirk M Welker
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA
| | - Charles D Blaha
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Bryan T Klassen
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Hoon-Ki Min
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA; Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
| | - Kendall H Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
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Padmanabhan D, Jondal ML, Hodge DO, Mehta RA, Acker NG, Dalzell CM, Kapa S, Asirvatham SJ, Cha YM, Felmlee JP, Watson RE, Friedman PA. Mortality After Magnetic Resonance Imaging of the Brain in Patients With Cardiovascular Implantable Devices. Circ Arrhythm Electrophysiol 2018; 11:e005480. [DOI: 10.1161/circep.117.005480] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 11/30/2017] [Indexed: 11/16/2022]
Affiliation(s)
- Deepak Padmanabhan
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Mary L. Jondal
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - David O. Hodge
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Ramila A. Mehta
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Nancy G. Acker
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Connie M. Dalzell
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Suraj Kapa
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Samuel J. Asirvatham
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Yong-Mei Cha
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Joel P. Felmlee
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Robert E. Watson
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
| | - Paul A. Friedman
- From the Division of Cardiovascular Diseases (D.P., N.G.A., C.M.D., S.K., S.J.A., Y.-M.C., P.A.F.), Department of Radiology (M.L.J., J.P.F., R.E.W.), and Division of Biomedical Statistics and Informatics (R.A.M.), Mayo Clinic, Rochester, MN; and Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL (D.O.H.)
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Padmanabhan D, Kella DK, Mehta R, Kapa S, Deshmukh A, Mulpuru S, Jaffe AS, Felmlee JP, Jondal ML, Dalzell CM, Asirvatham SJ, Cha YM, Watson RE, Friedman PA. Safety of magnetic resonance imaging in patients with legacy pacemakers and defibrillators and abandoned leads. Heart Rhythm 2017; 15:228-233. [PMID: 29045806 DOI: 10.1016/j.hrthm.2017.10.022] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND During magnetic resonance imaging (MRI), abandoned leads may act as antennae that result in tissue heating and arrhythmia induction. OBJECTIVE The purpose of this study was to assess the safety of MRI in patients with abandoned leads, with the addition of cardiac troponin T (cTnT) assessment to screen for myocardial damage. METHODS We reviewed our prospectively collected database of patients with cardiovascular implantable electronic devices (CIEDs) undergoing MRI between 2008 and 2017 at Mayo Clinic, Rochester, MN, and selected patients who had abandoned leads. We compared the adverse events in this population with an age, sex, and site of MRI-matched cohort of patients selected from this database. We evaluated paired (before/after) cTnT values using MRI in these patients. RESULTS Of 952 patients, 80 (8.4%) underwent 97 MRI scans with CIEDs in situ with 90 abandoned leads in place during the scans. The median age was 66 years (interquartile range 22.3 years) 66.1 years (interquartile range, Q1,Q3: 53.6, 75.9) with 66.3% (53 patients) men. There was no clinical or electrical evidence of CIED dysfunction, arrhythmias, or pain. Paired samples for the measurement of cTnT values were available in 40 patients undergoing 44 MRI examinations. The mean difference between the pre- and postimaging values was -0.002 ± 0.006 ng/mL (interquartile range 0). There was no difference after adjustment for total number of leads per patient and total number of implantable cardioverter-defibrillator coils. CONCLUSION There was no evidence of myocardial injury as measured by paired cTnT. The risk of MRI with abandoned leads appears low, suggesting a favorable risk-benefit profile in patients with CIEDs and abandoned leads who are considered for MRI.
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Affiliation(s)
| | - Danesh K Kella
- Division of Cardiovascular Diseases, Rochester, Minnesota
| | - Ramila Mehta
- Division of Biomedical Statistics and Informatics, Rochester, Minnesota
| | - Suraj Kapa
- Division of Cardiovascular Diseases, Rochester, Minnesota
| | | | - Siva Mulpuru
- Division of Cardiovascular Diseases, Rochester, Minnesota
| | - Allan S Jaffe
- Division of Cardiovascular Diseases, Rochester, Minnesota
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | - Mary L Jondal
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | | | | | - Yong-Mei Cha
- Division of Cardiovascular Diseases, Rochester, Minnesota
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19
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Favazza CP, Edmonson HA, Ma C, Shu Y, Felmlee JP, Watson RE, Gorny KR. Evaluation of feasibility of 1.5 Tesla prostate MRI using body coil RF transmit in a patient with an implanted vagus nerve stimulator. Med Phys 2017; 44:5749-5754. [PMID: 28880381 DOI: 10.1002/mp.12567] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 06/29/2017] [Accepted: 08/23/2017] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To assess risks of RF-heating of a vagus nerve stimulator (VNS) during 1.5 T prostate MRI using body coil transmit and to compare these risks with those associated with MRI head exams using a transmit/receive head coil. METHODS Spatial distributions of radio-frequency (RF) B1 fields generated by transmit/receive (T/R) body and head coils were empirically assessed along the long axis of a 1.5 T MRI scanner bore. Measurements were obtained along the center axis of the scanner and laterally offset by 15 cm (body coil) and 7 cm (head coil). RF-field measurements were supplemented with direct measurements of RF-heating of 15 cm long copper wires affixed to and submerged in the "neck" region of the gelled saline-filled (sodium chloride and polyacrylic acid) "head-and-torso" phantom. Temperature elevations at the lead tips were measured using fiber-optic thermometers with the phantom positioned at systematically increased distances from the scanner isocenter. RESULTS B1 field measurements demonstrated greater than 10 dB reduction in RF power at distances beyond 28 cm and 24 cm from isocenter for body and head coil, respectively. Moreover, RF power from body coil transmit at distances greater than 32 cm from isocenter was found to be lower than from the RF power from head coil transmit measured at locations adjacent to the coil array at its opening. Correspondingly, maximum temperature elevations at the tips of the copper wires decreased with increasing distance from isocenter - from 7.4°C at 0 cm to no appreciable heating at locations beyond 40 cm. CONCLUSIONS For the particular scanner model evaluated in this study, positioning an implanted VNS farther than 32 cm from isocenter (configuration achievable for prostate exams) can reduce risks of RF-heating resulting from the body coil transmit to those associated with using a T/R head coil.
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Affiliation(s)
| | | | - Chi Ma
- Department of Radiology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Yunhong Shu
- Department of Radiology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Robert E Watson
- Department of Radiology, Mayo Clinic, Rochester, MN, 55905, USA
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Gibson WS, Cho S, Abulseoud OA, Gorny KR, Felmlee JP, Welker KM, Klassen BT, Min HK, Lee KH. The Impact of Mirth-Inducing Ventral Striatal Deep Brain Stimulation on Functional and Effective Connectivity. Cereb Cortex 2017; 27:2183-2194. [PMID: 27001680 DOI: 10.1093/cercor/bhw074] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Deep brain stimulation (DBS) of the ventral capsule/ventral striatum (VC/VS) is an investigational therapy for treatment-resistant obsessive-compulsive disorder. The ability of VC/VS DBS to evoke spontaneous mirth in patients, often accompanied by smiling and laughter, is clinically well documented. However, the neural correlates of DBS-evoked mirth remain poorly characterized. Patients undergoing VC/VS DBS surgery underwent intraoperative evaluation in which mirth-inducing and non-mirth-inducing stimulation localizations were identified. Using dynamic causal modeling (DCM) for fMRI, the effect of mirth-inducing DBS on functional and effective connectivity among established nodes in limbic cortico-striato-thalamo-cortical (CSTC) circuitry was investigated. Both mirth-inducing and non-mirth-inducing VC/VS DBS consistently resulted (conjunction, global null, family-wise error-corrected P < 0.05) in activation of amygdala, ventral striatum, and mediodorsal thalamus. However, only mirth-inducing DBS resulted in functional inhibition of anterior cingulate cortex. Dynamic causal modeling revealed that mirth-inducing DBS enhanced effective connectivity from anterior cingulate to ventral striatum, while attenuating connectivity from thalamus to ventral striatum relative to non-mirth-inducing stimulation. These results suggest that DBS-evoked mood elevation is accompanied by distinct patterns of limbic thalamocortical connectivity. Using the novel combination of DBS-evoked mood alteration and functional MRI in human subjects, we provide new insights into the network-level mechanisms that influence affect.
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Affiliation(s)
| | | | - Osama A Abulseoud
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN 55906, USA.,National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | | | | | | | | | - Hoon-Ki Min
- Department of Neurologic Surgery.,Department of Radiology.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Kendall H Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, US.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
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Amano K, Li AK, Pedoia V, Koff MF, Krych AJ, Link TM, Potter H, Rodeo S, Li X, Ma CB, Majumdar S, Goldring M, Hannafin JA, Marx RG, Nawabi DH, Otero M, Shah P, Warren RF, Amrami KK, Felmlee JP, Frick MA, Stuart MJ, Williams SL, Kretzchmar M, Lansdown DA, Okazaki N, Russell C, Savic D, Schwaiger B, Su F, Wyatt C, Cheong M, Hardin JA. Effects of Surgical Factors on Cartilage Can Be Detected Using Quantitative Magnetic Resonance Imaging After Anterior Cruciate Ligament Reconstruction. Am J Sports Med 2017; 45:1075-1084. [PMID: 28768432 DOI: 10.1177/0363546516677794] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Quantitative magnetic resonance (qMR) can be used to measure macromolecules in tissues and is a potential method of observing early cartilage changes in the development of posttraumatic osteoarthritis. Hypothesis/Purpose: We hypothesized that specific patient and surgical factors affecting cartilage matrix composition after anterior cruciate ligament (ACL) reconstruction (ACLR) can be detected using T1ρ and T2 relaxation times. Our purpose was to demonstrate this ability in a multicenter feasibility study. STUDY DESIGN Case series; Level of evidence, 4. METHODS A total of 54 patients who underwent ACLR underwent bilateral MRI at baseline before surgery and 6 months postoperatively. Operative findings were recorded. T1ρ and T2 relaxation times were calculated for 6 cartilage regions: the medial femur, lateral femur, medial tibia, lateral tibia, patella, and trochlea. A paired t test compared relaxation times at baseline and 6 months, univariate regression identified regions that influenced patient-reported outcome measures, and analysis of covariance was used to determine the surgical factors that resulted in elevated relaxation times at 6 months. RESULTS The injured knee had significantly prolonged T1ρ and T2 relaxation times in the tibiofemoral compartment at baseline and 6 months but had shorter values in the patellofemoral compartment compared with the uninjured knee. Prolonged T1ρ and T2 times at 6 months were noted for both the injured and uninjured knees. At 6 months, prolongation of T1ρ and T2 times in the tibial region was associated with lower patient-reported outcome measures. ACLR performed within 30 days of injury had significantly shorter T1ρ times in the tibial regions, and lateral meniscal tears treated with repair had significantly shorter T1ρ times than those treated with excision. CONCLUSION Prolonged relaxation times in multiple regions demonstrate how the injury affects the entire joint after an ACL tear. Changes observed in the uninjured knee may be caused by increased loading during rehabilitation, especially in the patellofemoral articular cartilage and distal femur. Relaxation times in the tibial regions may be predictive of patient symptoms at 6 months. These same regions are affected by surgical timing as early as 30 days after injury, but this may partially be reflective of the severity of the preoperative injury and the choice of treatment of meniscal tears.
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Affiliation(s)
- Keiko Amano
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, California, USA
| | - Alan K Li
- University of California, Berkeley, Berkeley, California, USA
| | - Valentina Pedoia
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Matthew F Koff
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York, USA.,Weill Cornell Medical College, Cornell University, New York, New York, USA
| | | | - Thomas M Link
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Hollis Potter
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York, USA.,Weill Cornell Medical College, Cornell University, New York, New York, USA
| | - Scott Rodeo
- Weill Cornell Medical College, Cornell University, New York, New York, USA.,Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, New York, USA
| | - Xiaojuan Li
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - C Benjamin Ma
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, California, USA
| | - Sharmila Majumdar
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, California, USA.,Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.,Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA
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- All members are listed in the Contributing Authors section at the end of this article
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22
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Okamura H, Padmanabhan D, Watson RE, Dalzell C, Acker N, Jondal M, Romme AL, Cha YM, Asirvatham SJ, Felmlee JP, Friedman PA. Magnetic Resonance Imaging in Nondependent Pacemaker Patients with Pacemakers and Defibrillators with a Nearly Depleted Battery. Pacing Clin Electrophysiol 2017; 40:476-481. [PMID: 28169434 DOI: 10.1111/pace.13042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/17/2017] [Accepted: 01/22/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Magnetic resonance imaging (MRI) in patients with non-MRI-conditional cardiac implantable electronic devices (CIEDs) has been shown to be safe when performed under closely monitored protocols. However, the safety of MRI in patients with devices with a nearly depleted battery has not been reported. METHODS Prospective data were collected between January 2008 and May 2015 in patients with non-MRI-conditional CIEDs undergoing clinically indicated MRI under institutional protocol. Patients who were pacemaker dependent were excluded. Patients whose devices were at elective replacement indicator (ERI) at the time of MRI or close to ERI (ERI or replacement for battery depletion within 3 months of scan) were identified through database review and analyzed for clinical events. RESULTS MRI scans (n = 569) were performed in 442 patients. Of these, we identified 13 scans performed with a nearly depleted battery in nine patients. All scans with implantable cardioverter defibrillators (ICDs, n = 9) were uneventful. However, two scans with pacemakers close to ERI resulted in a power-on-reset (PoR) event. One scan with a pacemaker close to ERI that was programmed to DOO mode reached ERI during MRI and automatically changed to VVI mode. Additionally, one scan with a pacemaker at ERI did not allow programming. All pacemakers with events were implanted before 2005. CONCLUSION Patients with pacemakers and ICDs with a nearly depleted battery can safely undergo MRI when patients are not pacemaker dependent. Attention should be paid because old devices can result in PoR or ERI during MRI, which may lead to oversensing and inhibition of pacing.
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Affiliation(s)
- Hideo Okamura
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | | | - Robert E Watson
- Division of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota
| | - Connie Dalzell
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Nancy Acker
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Mary Jondal
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Abby L Romme
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Yong-Mei Cha
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | | | - Joel P Felmlee
- Division of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota
| | - Paul A Friedman
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
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23
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Burrows AM, Marsh WR, Worrell G, Woodrum DA, Pollock BE, Gorny KR, Felmlee JP, Watson RE, Kaufmann TJ, Goerss S, Van Gompel JJ. Magnetic resonance imaging–guided laser interstitial thermal therapy for previously treated hypothalamic hamartomas. Neurosurg Focus 2016; 41:E8. [DOI: 10.3171/2016.7.focus16218] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE
Hypothalamic hamartomas (HHs) are associated with gelastic seizures and the development of medically refractory epilepsy. Magnetic resonance imaging–guided laser interstitial thermal therapy (MRg-LITT) is a minimally invasive ablative treatment that may have applicability for these deep-seated lesions. Here, the authors describe 3 patients with refractory HHs who they treated with MRg-LITT.
METHODS
An institutional review board–approved prospective database of patients undergoing Visualase MRg-LITT was retrospectively reviewed. Demographic and historical medical data, including seizure and medication histories, previous surgeries, procedural details, and surgical complications, along with radiological interpretation of the HHs, were recorded. The primary outcome was seizure freedom, and secondary outcomes included medication reduction, seizure frequency, operative morbidity, and clinical outcome at the latest follow-up.
RESULTS
All 3 patients in the multi-institutional database had developed gelastic seizures related to HH at the ages of 7, 7, and 9 years. They presented for further treatment at 25, 28, and 48 years of age, after previous treatments with stereotactic radiosurgery in all cases and partial hamartoma resection in one case. One ablation was complicated by a small tract hemorrhage, which was stable on postoperative imaging. One patient developed hyponatremia and experienced weight gain, which were respectively managed with fluid restriction and counseling. At the most recent follow-up at a mean of 21 months (range 1–32 months), one patient was seizure free while another had meaningful seizure reduction. Medication was reduced in one case.
CONCLUSIONS
Adults with gelastic seizures despite previous treatments can undergo MRg-LITT with reasonable safety and efficacy. This novel therapy may provide a minimally invasive alternative for primary and recurrent HH as the technique is refined.
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Ma C, Long Z, Lanners DM, Tradup DJ, Brunnquell CL, Felmlee JP, Woodrum DA, Watson RE, Hangiandreou NJ, Gorny KR. Protocol for testing suitability of compact US imaging systems for use inside MRI suites, and application to one commercial US system. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/4/047003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Gibson WS, Jo HJ, Testini P, Cho S, Felmlee JP, Welker KM, Klassen BT, Min HK, Lee KH. Functional correlates of the therapeutic and adverse effects evoked by thalamic stimulation for essential tremor. Brain 2016; 139:2198-210. [PMID: 27329768 PMCID: PMC4958905 DOI: 10.1093/brain/aww145] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/03/2016] [Indexed: 01/05/2023] Open
Abstract
Thalamic deep brain stimulation (DBS) is an effective therapy for essential tremor. Gibson et al. use functional MRI to reveal patterns of activation that correlate with stimulation-induced therapeutic and adverse effects. Their results suggest that thalamic DBS controls tremor, and induces paraesthesias, through distal modulation of tremor-related network nodes. Deep brain stimulation is an established neurosurgical therapy for movement disorders including essential tremor and Parkinson’s disease. While typically highly effective, deep brain stimulation can sometimes yield suboptimal therapeutic benefit and can cause adverse effects. In this study, we tested the hypothesis that intraoperative functional magnetic resonance imaging could be used to detect deep brain stimulation-evoked changes in functional and effective connectivity that would correlate with the therapeutic and adverse effects of stimulation. Ten patients receiving deep brain stimulation of the ventralis intermedius thalamic nucleus for essential tremor underwent functional magnetic resonance imaging during stimulation applied at a series of stimulation localizations, followed by evaluation of deep brain stimulation-evoked therapeutic and adverse effects. Correlations between the therapeutic effectiveness of deep brain stimulation (3 months postoperatively) and deep brain stimulation-evoked changes in functional and effective connectivity were assessed using region of interest-based correlation analysis and dynamic causal modelling, respectively. Further, we investigated whether brain regions might exist in which activation resulting from deep brain stimulation might correlate with the presence of paraesthesias, the most common deep brain stimulation-evoked adverse effect. Thalamic deep brain stimulation resulted in activation within established nodes of the tremor circuit: sensorimotor cortex, thalamus, contralateral cerebellar cortex and deep cerebellar nuclei (FDR q < 0.05). Stimulation-evoked activation in all these regions of interest, as well as activation within the supplementary motor area, brainstem, and inferior frontal gyrus, exhibited significant correlations with the long-term therapeutic effectiveness of deep brain stimulation (P < 0.05), with the strongest correlation (P < 0.001) observed within the contralateral cerebellum. Dynamic causal modelling revealed a correlation between therapeutic effectiveness and attenuated within-region inhibitory connectivity in cerebellum. Finally, specific subregions of sensorimotor cortex were identified in which deep brain stimulation-evoked activation correlated with the presence of unwanted paraesthesias. These results suggest that thalamic deep brain stimulation in tremor likely exerts its effects through modulation of both olivocerebellar and thalamocortical circuits. In addition, our findings indicate that deep brain stimulation-evoked functional activation maps obtained intraoperatively may contain predictive information pertaining to the therapeutic and adverse effects induced by deep brain stimulation.
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Affiliation(s)
- William S Gibson
- 1 Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA 55905, USA
| | - Hang Joon Jo
- 1 Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA 55905, USA
| | - Paola Testini
- 1 Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA 55905, USA
| | - Shinho Cho
- 1 Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA 55905, USA
| | - Joel P Felmlee
- 2 Department of Radiology, Mayo Clinic, Rochester, MN, USA 55905, USA
| | - Kirk M Welker
- 2 Department of Radiology, Mayo Clinic, Rochester, MN, USA 55905, USA
| | - Bryan T Klassen
- 3 Department of Neurology, Mayo Clinic, Rochester, MN, USA 55905, USA
| | - Hoon-Ki Min
- 1 Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA 55905, USA 2 Department of Radiology, Mayo Clinic, Rochester, MN, USA 55905, USA 4 Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, USA
| | - Kendall H Lee
- 1 Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA 55905, USA 4 Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, USA
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26
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Ben-Abraham EI, Chen J, Felmlee JP, Rossman P, Manduca A, An KN, Ehman RL. Feasibility of MR elastography of the intervertebral disc. Magn Reson Imaging 2015; 39:132-137. [PMID: 26743429 DOI: 10.1016/j.mri.2015.12.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 12/27/2015] [Indexed: 01/07/2023]
Abstract
Low back pain (LBP) is a costly and widely prevalent health disorder in the U.S. One of the most common causes of LBP is degenerative disc disease (DDD). There are many imaging techniques to characterize disc degeneration; however, there is no way to directly assess the material properties of the intervertebral disc (IVD) within the intact spine. Magnetic resonance elastography (MRE) is an MRI-based technique for non-invasively mapping the mechanical properties of tissues in vivo. The purpose of this study was to investigate the feasibility of using MRE to detect shear wave propagation in and determine the shear stiffness of an axial cross-section of an ex vivo baboon IVD, and compare with shear displacements from a finite element model of an IVD motion segment in response to harmonic shear vibration. MRE was performed on two baboon lumbar spine motion segments (L3-L4) with the posterior elements removed at a range of frequencies (1000-1500Hz) using a standard clinical 1.5T MR scanner. Propagating waves were visualized in an axial cross-section of the baboon IVDs in all three motion-encoding directions, which resembled wave patterns predicted using finite element modeling. The baboon nucleus pulposus showed an average shear stiffness of 79±15kPa at 1000Hz. These results suggest that MRE is capable of visualizing shear wave propagation in the IVD, assessing the stiffness of the nucleus of the IVD, and can differentiate the nucleus and annulus regions.
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Affiliation(s)
- Ephraim I Ben-Abraham
- Mayo Graduate School, Biomedical Engineering and Physiology Track, Mayo Clinic, Rochester, Minnesota, USA.
| | - Jun Chen
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
| | - Phil Rossman
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
| | - Armando Manduca
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
| | - Kai-Nan An
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
| | - Richard L Ehman
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
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Murphy MC, Jones DT, Jack CR, Glaser KJ, Senjem ML, Manduca A, Felmlee JP, Carter RE, Ehman RL, Huston J. Regional brain stiffness changes across the Alzheimer's disease spectrum. Neuroimage Clin 2015; 10:283-90. [PMID: 26900568 PMCID: PMC4724025 DOI: 10.1016/j.nicl.2015.12.007] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 12/11/2015] [Accepted: 12/15/2015] [Indexed: 12/13/2022]
Abstract
Magnetic resonance elastography (MRE) is an MRI-based technique to noninvasively measure tissue stiffness. Currently well established for clinical use in the liver, MRE is increasingly being investigated to measure brain stiffness as a novel biomarker of a variety of neurological diseases. The purpose of this work was to apply a recently developed MRE pipeline to measure regional brain stiffness changes in human subjects across the Alzheimer's disease (AD) spectrum, and to gain insights into the biological processes underlying those stiffness changes by correlating stiffness with existing biomarkers of AD. The results indicate that stiffness changes occur mostly in the frontal, parietal and temporal lobes, in accordance with the known topography of AD pathology. Furthermore, stiffness in those areas correlates with existing imaging biomarkers of AD including hippocampal volumes and amyloid PET. Additional analysis revealed preliminary but significant evidence that the relationship between brain stiffness and AD severity is nonlinear and non-monotonic. Given that similar relationships have been observed in functional MRI experiments, we used task-free fMRI data to test the hypothesis that brain stiffness was sensitive to structural changes associated with altered functional connectivity. The analysis revealed that brain stiffness is significantly and positively correlated with default mode network connectivity. Therefore, brain stiffness as measured by MRE has potential to provide new and essential insights into the temporal dynamics of AD, as well as the relationship between functional and structural plasticity as it relates to AD pathophysiology.
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Affiliation(s)
- Matthew C Murphy
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - David T Jones
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA; Department of Neurology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Clifford R Jack
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Kevin J Glaser
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Matthew L Senjem
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Armando Manduca
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Rickey E Carter
- Department of Health Sciences Research, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Richard L Ehman
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - John Huston
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
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Abstract
Intramuscular pressure (IMP), a correlate of muscle tension, may fill an important clinical testing void. A barrier to implementing this measure clinically is its non-uniform distribution, which is not fully understood. Pressure is generated by changes in fluid mass and volume, therefore 3D volumetric strain distribution may affect IMP distribution. The purpose of this study was to develop a method for quantifying 3D volumetric strain distribution in the human tibialis anterior (TA) during passive tension using cine phase contrast (CPC) MRI and to assess its accuracy and precision.Five healthy subjects each participated in three data collections. A custom MRI-compatible apparatus repeatedly rotated a subject's ankle between 0° and 26° plantarflexion while CPC MRI data were collected. Additionally, T2-weighted images of the lower leg were collected both before and after the CPC data collection with the ankle stationary at both 0° and 26° plantarflexion for TA muscle segmentation. A 3D hexahedral mesh was generated based on the TA surface before CPC data collection with the ankle at 0° plantarflexion and the node trajectories were tracked using the CPC data. The volumetric strain of each element was quantified.Three tests were employed to assess the measure accuracy and precision. First, to quantify leg position drift, the TA segmentations were compared before and after CPC data collection. The Hawsdorff distance measure (error) was 1.5 ± 0.7 mm. Second, to assess the surface node trajectory accuracy, the deformed mesh surface was compared to the TA segmented at 26° of ankle plantarflexion. This error was 0.6 ± 0.2 mm. Third, the standard deviation of volumetric strain across the three data collections was calculated for each element and subject. The median between-day variability across subjects and mesh elements was 0.06 mm3 mm(-3) (95% confidence interval 0.01 to 0.18 mm3 mm(-3)). Overall the results demonstrated excellent accuracy and precision.
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Affiliation(s)
- Elisabeth R. Jensen
- Mayo Graduate School, Biomedical Engineering and Physiology Track,
Mayo Clinic, Rochester, MN 55905 USA
- Motion Analysis Laboratory, Division of Orthopedic Research, Mayo
Clinic, Rochester, MN 55905 USA
| | - Duane A. Morrow
- Motion Analysis Laboratory, Division of Orthopedic Research, Mayo
Clinic, Rochester, MN 55905 USA
| | - Joel P. Felmlee
- Department of Radiology, Mayo Clinic, Rochester, MN 55905 USA
| | | | - Kenton R. Kaufman
- Motion Analysis Laboratory, Division of Orthopedic Research, Mayo
Clinic, Rochester, MN 55905 USA
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Abstract
The proximal and distal radioulnar joints form a unique articular arrangement between the radius and ulna, allowing pivot motion of the forearm and positioning the hand in space. Typically imaged in conjunction with the elbow, radiographs, computed tomography (CT), and MR imaging of the proximal radioulnar joint contribute unique diagnostic information. Because dysfunction of the distal radioulnar joint is often a result of instability, dynamic CT protocols stressing the joint in addition to anatomic imaging with radiographs and MR imaging is valuable. Detailed knowledge of the patient's clinical condition and careful selection of imaging protocols will maximize the benefits.
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Affiliation(s)
- Eric C Ehman
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143, USA.
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Matthew A Frick
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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30
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Knight EJ, Testini P, Min HK, Gibson WS, Gorny KR, Favazza CP, Felmlee JP, Kim I, Welker KM, Clayton DA, Klassen BT, Chang SY, Lee KH. Motor and Nonmotor Circuitry Activation Induced by Subthalamic Nucleus Deep Brain Stimulation in Patients With Parkinson Disease: Intraoperative Functional Magnetic Resonance Imaging for Deep Brain Stimulation. Mayo Clin Proc 2015; 90:773-85. [PMID: 26046412 PMCID: PMC4469128 DOI: 10.1016/j.mayocp.2015.03.022] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [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: 01/16/2015] [Revised: 03/05/2015] [Accepted: 03/24/2015] [Indexed: 01/20/2023]
Abstract
OBJECTIVE To test the hypothesis suggested by previous studies that subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with Parkinson disease would affect the activity of motor and nonmotor networks, we applied intraoperative functional magnetic resonance imaging (fMRI) to patients receiving DBS. PATIENTS AND METHODS Ten patients receiving STN DBS for Parkinson disease underwent intraoperative 1.5-T fMRI during high-frequency stimulation delivered via an external pulse generator. The study was conducted between January 1, 2013, and September 30, 2014. RESULTS We observed blood oxygen level-dependent (BOLD) signal changes (false discovery rate <0.001) in the motor circuitry (including the primary motor, premotor, and supplementary motor cortices; thalamus; pedunculopontine nucleus; and cerebellum) and in the limbic circuitry (including the cingulate and insular cortices). Activation of the motor network was observed also after applying a Bonferroni correction (P<.001) to the data set, suggesting that across patients, BOLD changes in the motor circuitry are more consistent compared with those occurring in the nonmotor network. CONCLUSION These findings support the modulatory role of STN DBS on the activity of motor and nonmotor networks and suggest complex mechanisms as the basis of the efficacy of this treatment modality. Furthermore, these results suggest that across patients, BOLD changes in the motor circuitry are more consistent than those in the nonmotor network. With further studies combining the use of real-time intraoperative fMRI with clinical outcomes in patients treated with DBS, functional imaging techniques have the potential not only to elucidate the mechanisms of DBS functioning but also to guide and assist in the surgical treatment of patients affected by movement and neuropsychiatric disorders. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01809613.
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Affiliation(s)
- Emily J Knight
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN
| | - Paola Testini
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN
| | - Hoon-Ki Min
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN
| | | | | | | | | | - Inyong Kim
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN
| | | | | | | | - Su-youne Chang
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN.
| | - Kendall H Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN.
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Higgins JV, Sheldon SH, Watson RE, Dalzell C, Acker N, Cha YM, Asirvatham SJ, Kapa S, Felmlee JP, Friedman PA. “Power-on resets” in cardiac implantable electronic devices during magnetic resonance imaging. Heart Rhythm 2015; 12:540-544. [DOI: 10.1016/j.hrthm.2014.10.039] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Indexed: 10/24/2022]
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32
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Sheldon SH, Bunch TJ, Cogert GA, Acker NG, Dalzell CM, Higgins JV, Espinosa RE, Asirvatham SJ, Cha YM, Felmlee JP, Watson RE, Anderson JL, Brooks MH, Osborn JS, Friedman PA. Multicenter study of the safety and effects of magnetic resonance imaging in patients with coronary sinus left ventricular pacing leads. Heart Rhythm 2015; 12:345-9. [DOI: 10.1016/j.hrthm.2014.11.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Indexed: 11/28/2022]
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33
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Jensen ER, Morrow DA, Felmlee JP, Odegard GM, Kaufman KR. Error analysis of cine phase contrast MRI velocity measurements used for strain calculation. J Biomech 2015; 48:95-103. [PMID: 25433567 DOI: 10.1016/j.jbiomech.2014.10.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 10/30/2014] [Accepted: 10/31/2014] [Indexed: 11/19/2022]
Abstract
Cine Phase Contrast (CPC) MRI offers unique insight into localized skeletal muscle behavior by providing the ability to quantify muscle strain distribution during cyclic motion. Muscle strain is obtained by temporally integrating and spatially differentiating CPC-encoded velocity. The aim of this study was to quantify CPC measurement accuracy and precision and to describe error propagation into displacement and strain. Using an MRI-compatible jig to move a B-gel phantom within a 1.5 T MRI bore, CPC-encoded velocities were collected. The three orthogonal encoding gradients (through plane, frequency, and phase) were evaluated independently in post-processing. Two systematic error types were corrected: eddy current-induced bias and calibration-type error. Measurement accuracy and precision were quantified before and after removal of systematic error. Through plane- and frequency-encoded data accuracy were within 0.4 mm/s after removal of systematic error - a 70% improvement over the raw data. Corrected phase-encoded data accuracy was within 1.3 mm/s. Measured random error was between 1 to 1.4 mm/s, which followed the theoretical prediction. Propagation of random measurement error into displacement and strain was found to depend on the number of tracked time segments, time segment duration, mesh size, and dimensional order. To verify this, theoretical predictions were compared to experimentally calculated displacement and strain error. For the parameters tested, experimental and theoretical results aligned well. Random strain error approximately halved with a two-fold mesh size increase, as predicted. Displacement and strain accuracy were within 2.6 mm and 3.3%, respectively. These results can be used to predict the accuracy and precision of displacement and strain in user-specific applications.
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Affiliation(s)
- Elisabeth R Jensen
- Motion Analysis Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905 USA
| | - Duane A Morrow
- Motion Analysis Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905 USA
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, MN 55905 USA
| | - Gregory M Odegard
- Computational Mechanics and Materials Research Laboratory, Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, MI 49931 USA
| | - Kenton R Kaufman
- Motion Analysis Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905 USA.
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Favazza CP, King DM, Edmonson HA, Felmlee JP, Rossman PJ, Hangiandreou NJ, Watson RE, Gorny KR. Use of a radio frequency shield during 1.5 and 3.0 Tesla magnetic resonance imaging: experimental evaluation. Med Devices (Auckl) 2014; 7:363-70. [PMID: 25378957 PMCID: PMC4219642 DOI: 10.2147/mder.s68657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Radiofrequency (RF) shields have been recently developed for the purpose of shielding portions of the patient’s body during magnetic resonance imaging (MRI) examinations. We present an experimental evaluation of a commercially available RF shield in the MRI environment. All tests were performed on 1.5 T and 3.0 T clinical MRI scanners. The tests were repeated with and without the RF shield present in the bore, for comparison. Effects of the shield, placed within the scanner bore, on the RF fields generated by the scanner were measured directly using tuned pick-up coils. Attenuation, by as much as 35 dB, of RF field power was found inside the RF shield. These results were supported by temperature measurements of metallic leads placed inside the shield, in which no measurable RF heating was found. In addition, there was a small, simultaneous detectable increase (∼1 dB) of RF power just outside the edges of the shield. For these particular scanners, the autocalibrated RF power levels were reduced for scan locations prescribed just outside the edges of the shield, which corresponded with estimations based on the pick-up coil measurements. Additionally, no significant heating during MRI scanning was observed on the shield surface. The impact of the RF shield on the RF fields inside the magnet bore is likely to be dependent on the particular model of the RF shield or the MRI scanner. These results suggest that the RF shield could be a valuable tool for clinical MRI practices.
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Affiliation(s)
| | - Deirdre M King
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
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Shu Y, Gorny KR, Felmlee JP, Pooley RA, Edmonson HA. Practical considerations for ACR MRI accreditation. J Am Coll Radiol 2014; 11:94-6. [PMID: 24387966 DOI: 10.1016/j.jacr.2013.09.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 09/27/2013] [Indexed: 11/17/2022]
Affiliation(s)
- Yunhong Shu
- Department of Radiology, Mayo Clinic, Rochester, Minnesota.
| | | | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
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Higgins JV, Gard JJ, Sheldon SH, Espinosa RE, Wood CP, Felmlee JP, Cha YM, Asirvatham SJ, Dalzell C, Acker N, Watson RE, Friedman PA. Safety and outcomes of magnetic resonance imaging in patients with abandoned pacemaker and defibrillator leads. Pacing Clin Electrophysiol 2014; 37:1284-90. [PMID: 24809591 DOI: 10.1111/pace.12419] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 02/28/2014] [Accepted: 03/18/2014] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Abandoned cardiovascular implantable electronic device (CIED) leads remain a contraindication to magnetic resonance imaging (MRI) studies, largely due to in vitro data showing endocardial heating secondary to the radiofrequency field. We tested the hypothesis that abandoned CIED leads do not pose an increased risk of clinical harm for patients undergoing MRI. METHODS This single-center retrospective study examined the outcomes of patients who had device generators removed before MRI, rendering the device leads abandoned. Information was gathered through chart review. Data collected included lead model, pacing threshold before MRI, anatomic region examined, threshold data after generator reimplantation, and clinical patient outcome. RESULTS Patients (n = 19, 11 men and eight women) ranged in age from 19 to 85 at the time of MRI. There was a mean of 1.63 abandoned leads at the time of imaging; none of the leads were MRI conditional. Of the three implantable cardioverter defibrillator (ICD) leads, two of three were dual coil. Most (31/35) of the scans performed were of the central nervous system, including head and spinal imaging. There were no adverse events associated with MRI in any of these patients with abandoned leads within 7 days of the scan. No lead malfunctions or clinically significant change in pacing thresholds were noted with generator reimplantation. CONCLUSION The use of MRI in patients with abandoned cardiac device leads appears feasible when performed under careful monitoring, with no adverse events, although the experience is small. MRI did not affect the function of leads that were subsequently reconnected to a cardiac device.
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Affiliation(s)
- John V Higgins
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
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Min HK, Ross EK, Lee KH, Dennis K, Han SR, Jeong JH, Marsh MP, Striemer B, Felmlee JP, Lujan JL, Goerss S, Duffy PS, Blaha C, Chang SY, Bennet KE. Subthalamic nucleus deep brain stimulation induces motor network BOLD activation: use of a high precision MRI guided stereotactic system for nonhuman primates. Brain Stimul 2014; 7:603-607. [PMID: 24933029 DOI: 10.1016/j.brs.2014.04.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/19/2014] [Accepted: 04/25/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Functional magnetic resonance imaging (fMRI) is a powerful method for identifying in vivo network activation evoked by deep brain stimulation (DBS). OBJECTIVE Identify the global neural circuitry effect of subthalamic nucleus (STN) DBS in nonhuman primates (NHP). METHOD An in-house developed MR image-guided stereotactic targeting system delivered a mini-DBS stimulating electrode, and blood oxygenation level-dependent (BOLD) activation during STN DBS in healthy NHP was measured by combining fMRI with a normalized functional activation map and general linear modeling. RESULTS STN DBS significantly increased BOLD activation in the sensorimotor cortex, supplementary motor area, caudate nucleus, pedunculopontine nucleus, cingulate, insular cortex, and cerebellum (FDR < 0.001). CONCLUSION Our results demonstrate that STN DBS evokes neural network grouping within the motor network and the basal ganglia. Taken together, these data highlight the importance and specificity of neural circuitry activation patterns and functional connectivity.
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Affiliation(s)
- Hoon-Ki Min
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
- Division of Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Erika K Ross
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Kendall H Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Kendall Dennis
- Division of Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Seong Rok Han
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
- Department of Neurosurgery, Ilsan Paik Hospital, College of Medicine, Inje University, Goyang, Republic of Korea
| | - Ju Ho Jeong
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
- Department of Neurosurgery, Kosin University Gospel Hospital, Busan, Republic of Korea
| | - Michael P Marsh
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Bryan Striemer
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - J Luis Lujan
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
- Division of Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Steve Goerss
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Penelope S Duffy
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Charles Blaha
- Department of Psychology, University of Memphis, Memphis, Tennessee, USA
| | - Su-Youne Chang
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Kevin E Bennet
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
- Division of Engineering, Mayo Clinic, Rochester, Minnesota, USA
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Sheldon S, Bunch T, Cogert G, Acker N, Dalzell C, Higgins J, Espinosa R, Asirvatham S, Cha YM, Felmlee JP, Watson RE, Anderson J, Brooks MH, Osborn J, Friedman P. MULTICENTER STUDY OF THE SAFETY AND EFFECTS OF MAGNETIC RESONANCE IMAGING IN PATIENTS WITH CORONARY SINUS LEFT VENTRICULAR PACING LEADS. J Am Coll Cardiol 2014. [DOI: 10.1016/s0735-1097(14)60380-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Murphy MC, Huston J, Jack CR, Glaser KJ, Senjem ML, Chen J, Manduca A, Felmlee JP, Ehman RL. Measuring the characteristic topography of brain stiffness with magnetic resonance elastography. PLoS One 2013; 8:e81668. [PMID: 24312570 PMCID: PMC3847077 DOI: 10.1371/journal.pone.0081668] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 10/17/2013] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To develop a reliable magnetic resonance elastography (MRE)-based method for measuring regional brain stiffness. METHODS First, simulation studies were used to demonstrate how stiffness measurements can be biased by changes in brain morphometry, such as those due to atrophy. Adaptive postprocessing methods were created that significantly reduce the spatial extent of edge artifacts and eliminate atrophy-related bias. Second, a pipeline for regional brain stiffness measurement was developed and evaluated for test-retest reliability in 10 healthy control subjects. RESULTS This technique indicates high test-retest repeatability with a typical coefficient of variation of less than 1% for global brain stiffness and less than 2% for the lobes of the brain and the cerebellum. Furthermore, this study reveals that the brain possesses a characteristic topography of mechanical properties, and also that lobar stiffness measurements tend to correlate with one another within an individual. CONCLUSION The methods presented in this work are resistant to noise- and edge-related biases that are common in the field of brain MRE, demonstrate high test-retest reliability, and provide independent regional stiffness measurements. This pipeline will allow future investigations to measure changes to the brain's mechanical properties and how they relate to the characteristic topographies that are typical of many neurologic diseases.
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Affiliation(s)
- Matthew C. Murphy
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - John Huston
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Clifford R. Jack
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Kevin J. Glaser
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Matthew L. Senjem
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Jun Chen
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Armando Manduca
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Joel P. Felmlee
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Richard L. Ehman
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
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Pooley RA, Felmlee JP, Gorny KR. MR Siting: Improving Efficiency and Safety. J Am Coll Radiol 2013; 10:721-2. [DOI: 10.1016/j.jacr.2013.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
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41
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Woodrum DA, Kawashima A, Karnes RJ, Davis BJ, Frank I, Engen DE, Gorny KR, Felmlee JP, Callstrom MR, Mynderse LA. Magnetic resonance imaging-guided cryoablation of recurrent prostate cancer after radical prostatectomy: initial single institution experience. Urology 2013; 82:870-5. [PMID: 23910089 DOI: 10.1016/j.urology.2013.06.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 05/30/2013] [Accepted: 06/05/2013] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To establish the feasibility of magnetic resonance imaging (MRI)-guided cryoablation in patients with previous radical prostatectomy and MRI visualized biopsy-proven local recurrence of prostate adenocarcinoma. MATERIALS AND METHODS Eighteen postprostatectomy patients (mean 67, 57-78 years) were treated with MRI-guided cryoablation for recurrent prostate carcinoma. Patients were found to have a hyperenhancing nodule using multiparametric MRI with endorectal coil followed by a positive transrectal ultrasound-guided biopsy. Of 18 postsurgical patients, 6 had additional salvage external beam radiation with subsequent recurrence. Under general anesthesia and MRI guidance (wide-bore 1.5T MRI), 2-5 cryotherapy probes were placed in or around the recurrence by transperineal approach and cryoablation performed. The patients were stratified into 2 groups: the initial 9 consecutive patients had cryoprobes placed 1 cm apart with 2 freeze-thaw cycles (group 1), and the subsequent 9 patients had cryoprobes placed 0.5 cm apart with 3 freeze-thaw cycles (group 2). RESULTS In group I, the average preprocedure prostate-specific antigen (PSA) was 1.21 ± 1.12 ng/mL, and 1-3 months postprocedure PSA was 0.14 ± 0.11 ng/mL (P <.01). Sixty-seven percent of patients had PSA ≤0.2 ng/mL at 1-3 months follow-up, but only 25% at 4-6 months. No change in impotence or incontinence occurred. In group II, average preprocedure PSA was 2.24 ± 2.71 ng/mL, and 1-3 month postprocedure PSA was 0.08 ± 0.10 ng/mL (P <.05). Eighty-nine percent of patients had PSA ≤0.2 ng/mL at 1-3 months follow-up and at 4-6 months. Complications in group 2 included worsening incontinence in 3 patients. CONCLUSION MRI-guided salvage cryoablation of postradical prostatectomy prostate cancer recurrence is safe and feasible. Both techniques produce early PSA decrease with more lasting PSA results in the more aggressive group II methodology.
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Knight EJ, Min HK, Hwang SC, Marsh MP, Paek S, Kim I, Felmlee JP, Abulseoud OA, Bennet KE, Frye MA, Lee KH. Nucleus accumbens deep brain stimulation results in insula and prefrontal activation: a large animal FMRI study. PLoS One 2013; 8:e56640. [PMID: 23441210 PMCID: PMC3575484 DOI: 10.1371/journal.pone.0056640] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 01/11/2013] [Indexed: 01/11/2023] Open
Abstract
Background Deep Brain Stimulation (DBS) of the nucleus accumbens (NAc) has previously been investigated clinically for the treatment of several psychiatric conditions, including obsessive-compulsive disorder and treatment resistant depression. However, the mechanism underlying the therapeutic benefit of DBS, including the brain areas that are activated, remains largely unknown. Here, we utilized 3.0 T functional Magnetic Resonance Imaging (fMRI) changes in Blood Oxygenation Level-Dependent (BOLD) signal to test the hypothesis that NAc/internal capsule DBS results in global neural network activation in a large animal (porcine) model Methods Animals (n = 10) were implanted in the NAc/internal capsule with DBS electrodes and received stimulation (1, 3, and 5 V, 130 Hz, and pulse widths of 100 and 500 µsec). BOLD signal changes were evaluated using a gradient echo-echo planar imaging (GRE-EPI) sequence in 3.0 T MRI. We used a normalized functional activation map for group analysis and applied general linear modeling across subjects (FDR<0.001). The anatomical location of the implanted DBS lead was confirmed with a CT scan Results We observed stimulation-evoked activation in the ipsilateral prefrontal cortex, insula, cingulate and bilateral parahippocampal region along with decrease in BOLD signal in the ipsilateral dorsal region of the thalamus. Furthermore, as the stimulation voltage increased from 3 V to 5 V, the region of BOLD signal modulation increased in insula, thalamus, and parahippocampal cortex and decreased in the cingulate and prefrontal cortex. We also demonstrated that right and left NAc/internal capsule stimulation modulates identical areas ipsilateral to the side of the stimulation Conclusions Our results suggest that NAc/internal capsule DBS results in modulation of psychiatrically important brain areas notably the prefrontal cortex, cingulate, and insular cortex, which may underlie the therapeutic effect of NAc DBS in psychiatric disorders. Finally, our fMRI setup in the large animal may be a useful platform for translational studies investigating the global neuromodulatory effects of DBS
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Affiliation(s)
- Emily J. Knight
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Hoon-Ki Min
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Sun-Chul Hwang
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Neurosurgery, Soonchunhyang University, Busheon Hospital, Bucheon, Republic of Korea
| | - Michael P. Marsh
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Seungleal Paek
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Inyong Kim
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Joel P. Felmlee
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Osama A. Abulseoud
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Kevin E. Bennet
- Division of Engineering, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Mark A. Frye
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Kendall H. Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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Murphy MC, Huston J, Glaser KJ, Manduca A, Meyer FB, Lanzino G, Morris JM, Felmlee JP, Ehman RL. Preoperative assessment of meningioma stiffness using magnetic resonance elastography. J Neurosurg 2012; 118:643-8. [PMID: 23082888 DOI: 10.3171/2012.9.jns12519] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECT The object of this study was to determine the potential of magnetic resonance elastography (MRE) to preoperatively assess the stiffness of meningiomas. METHODS Thirteen patients with meningiomas underwent 3D brain MRE examination to measure stiffness in the tumor as well as in surrounding brain tissue. Blinded to the MRE results, neurosurgeons made a qualitative assessment of tumor stiffness at the time of resection. The ability of MRE to predict the surgical assessment of stiffness was tested using a Spearman rank correlation. RESULTS One case was excluded due to a small tumor size. In the remaining 12 cases, both tumor stiffness alone (p = 0.023) and the ratio of tumor stiffness to surrounding brain tissue stiffness (p = 0.0032) significantly correlated with the surgeons' qualitative assessment of tumor stiffness. Results of the MRE examination provided a stronger correlation with the surgical assessment of stiffness compared with traditional T1- and T2-weighted imaging (p = 0.089), particularly when considering meningiomas of intermediate stiffness. CONCLUSIONS In this cohort, preoperative MRE predicted tumor consistency at the time of surgery. Tumor stiffness as measured using MRE outperformed conventional MRI because tumor appearance on T1- and T2-weighted images could only accurately predict the softest and hardest meningiomas.
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Affiliation(s)
- Matthew C Murphy
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Min HK, Hwang SC, Marsh MP, Kim I, Knight E, Striemer B, Felmlee JP, Welker KM, Blaha CD, Chang SY, Bennet KE, Lee KH. Deep brain stimulation induces BOLD activation in motor and non-motor networks: an fMRI comparison study of STN and EN/GPi DBS in large animals. Neuroimage 2012; 63:1408-20. [PMID: 22967832 DOI: 10.1016/j.neuroimage.2012.08.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 08/03/2012] [Accepted: 08/04/2012] [Indexed: 01/11/2023] Open
Abstract
The combination of deep brain stimulation (DBS) and functional MRI (fMRI) is a powerful means of tracing brain circuitry and testing the modulatory effects of electrical stimulation on a neuronal network in vivo. The goal of this study was to trace DBS-induced global neuronal network activation in a large animal model by monitoring the blood oxygenation level-dependent (BOLD) response on fMRI. We conducted DBS in normal anesthetized pigs, targeting the subthalamic nucleus (STN) (n=7) and the entopeduncular nucleus (EN), the non-primate analog of the primate globus pallidus interna (n=4). Using a normalized functional activation map for group analysis and the application of general linear modeling across subjects, we found that both STN and EN/GPi DBS significantly increased BOLD activation in the ipsilateral sensorimotor network (FDR<0.001). In addition, we found differential, target-specific, non-motor network effects. In each group the activated brain areas showed a distinctive correlation pattern forming a group of network connections. Results suggest that the scope of DBS extends beyond an ablation-like effect and that it may have modulatory effects not only on circuits that facilitate motor function but also on those involved in higher cognitive and emotional processing. Taken together, our results show that the swine model for DBS fMRI, which conforms to human implanted DBS electrode configurations and human neuroanatomy, may be a useful platform for translational studies investigating the global neuromodulatory effects of DBS.
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Affiliation(s)
- Hoon-Ki Min
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
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Murphy MC, Curran GL, Glaser KJ, Rossman PJ, Huston J, Poduslo JF, Jack CR, Felmlee JP, Ehman RL. Magnetic resonance elastography of the brain in a mouse model of Alzheimer's disease: initial results. Magn Reson Imaging 2012; 30:535-9. [PMID: 22326238 DOI: 10.1016/j.mri.2011.12.019] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 09/15/2011] [Accepted: 12/18/2011] [Indexed: 11/19/2022]
Abstract
The increasing prevalence of Alzheimer's disease (AD) has provided motivation for developing novel methods for assessing the disease and the effects of potential treatments. Magnetic resonance elastography (MRE) is an MRI-based method for quantitatively imaging the shear tissue stiffness in vivo. The objective of this research was to determine whether this new imaging biomarker has potential for characterizing neurodegenerative disease. Methods were developed and tested for applying MRE to evaluate the mouse brain, using a conventional large bore 3.0T MRI system. The technique was then applied to study APP-PS1 mice, a well-characterized model of AD. Five APP-PS1 mice and 8 age-matched wild-type mice were imaged immediately following sacrifice. Brain shear stiffness measurements in APP-PS1 mice averaged 22.5% lower than those for wild-type mice (P = .0031). The results indicate that mouse brain MRE is feasible at 3.0T, and brain shear stiffness has merit for further investigation as a potential new biomarker for Alzheimer's disease.
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Affiliation(s)
- Matthew C Murphy
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Murphy MC, Huston J, Jack CR, Glaser KJ, Manduca A, Felmlee JP, Ehman RL. Decreased brain stiffness in Alzheimer's disease determined by magnetic resonance elastography. J Magn Reson Imaging 2011; 34:494-8. [PMID: 21751286 DOI: 10.1002/jmri.22707] [Citation(s) in RCA: 240] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 06/06/2011] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To test patient acceptance and reproducibility of the 3D magnetic resonance elastography (MRE) brain exam using a soft vibration source, and to determine if MRE could noninvasively measure a change in the elastic properties of the brain parenchyma due to Alzheimer's disease (AD). MATERIALS AND METHODS MRE exams were performed using an accelerated spin-echo echo planar imaging (EPI) pulse sequence and stiffness was calculated with a 3D direct inversion algorithm. Reproducibility of the technique was assessed in 10 male volunteers, who each underwent four MRE exams separated into two imaging sessions. The effect of AD on brain stiffness was assessed in 28 volunteers, 7 with probable AD, 14 age- and gender-matched PIB-negative (Pittsburgh Compound B, a PET amyloid imaging ligand) cognitively normal controls (CN-), and 7 age- and gender-matched PIB-positive cognitively normal controls (CN+). RESULTS The median stiffness of the 10 volunteers was 3.07 kPa with a range of 0.40 kPa. The median and maximum coefficients of variation for these volunteers were 1.71% and 3.07%. The median stiffness of the 14 CN- subjects was 2.37 kPa (0.44 kPa range) compared to 2.32 kPa (0.49 kPa range) within the CN+ group and 2.20 kPa (0.33 kPa range) within the AD group. A significant difference was found between the three groups (P = 0.0055, Kruskal-Wallis one-way analysis of variance). Both the CN+ and CN- groups were significantly different from the AD group. CONCLUSION 3D MRE of the brain can be performed reproducibly and demonstrates significantly reduced brain tissue stiffness in patients with AD.
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Affiliation(s)
- Matthew C Murphy
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Murphy MC, Glaser KJ, Manduca A, Felmlee JP, Huston J, Ehman RL. Analysis of time reduction methods for magnetic resonance elastography of the brain. Magn Reson Imaging 2011; 28:1514-24. [PMID: 20817440 DOI: 10.1016/j.mri.2010.06.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 04/29/2010] [Accepted: 06/25/2010] [Indexed: 11/17/2022]
Abstract
Magnetic resonance elastography (MRE) uses a phase-contrast MRI technique to image shear wave propagation in tissue followed by the mathematical inversion of the equations of motion governing tissue mechanics to noninvasively image tissue stiffness. This work investigates the impact of various MR sampling strategies designed to reduce acquisition times on the accuracy of MRE inversions. The results indicate that brain MRE data can be significantly truncated while maintaining a mean global stiffness error less than 10%. The results also indicate that brain MRE data can be collected in as few as eight lines of k-space. This degree of data truncation is possible due to the relatively low spatial frequency content and low amplitude of the shear waves observed during brain MRE exams and will facilitate the design of rapid brain MRE protocols for future clinical investigations.
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Shahid KR, Spinner RJ, Skinner JA, Felmlee JP, Bond JR, Stanley DW, Amrami KK. Evaluation of intraneural ganglion cysts using three-dimensional fast spin echo-cube. J Magn Reson Imaging 2011; 32:714-8. [PMID: 20815072 DOI: 10.1002/jmri.22286] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To compare conventional two-dimensional fast spin echo (FSE) MRI sequences with a three-dimensional FSE extended echo train acquisition method, known as Cube, in the evaluation of intraneural ganglion cysts. Also, to demonstrate that Cube enables the consistent identification and thorough characterization of the cystic joint connection, and therefore improves patient care by superior preoperative planning. MATERIALS AND METHODS Six patients with intraneural ganglia in the knee region (five involving the peroneal and one the tibial nerve) were evaluated using both conventional FSE MR sequences and the Cube sequence. Studies were interpreted by the consensus of three board certified musculoskeletal radiologists and one peripheral nerve neurosurgeon. Surgical correlation was available in five of the six cases. RESULTS Both imaging methods demonstrated the cysts and at least part of their joint connections after variable amount of postprocessing. Cube proved superior to conventional imaging in its ability to acquire isotropic data that could easily be reconstructed in any plane and its ability to resolve fine anatomical details. CONCLUSION Cube is a new MR pulse sequence that enables the consistent identification of the intraneural ganglion cyst joint connection. We believe that improved visualization and characterization of the entire cyst will improve patient outcomes by facilitating more accurate surgical intervention.
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Affiliation(s)
- Kameron R Shahid
- Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, USA
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Abstract
Imaging the DRUJ requires knowledge of the complex bony, muscular, and ligamentous anatomy that contribute to this unique joint. Standard well-positioned radiography is always the appropriate first step in any imaging evaluation of the wrist. High-resolution MRI of the wrist, preferably performed at 3T, helps to delineate the important ligamentous structures relevant to the DRUJ and ulnar wrist, whether the joint is unstable or not. The presence of instability on physical examination is an indication for dynamic CT evaluation. Close attention to technique, no matter what the modality of choice, offers the best chance for success in providing added value with imaging. Finally, communication between the radiologist and hand surgeon allows the advanced imaging examinations to be tailored to the specific clinical problem for the most effective use of resources for each individual patient.
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Affiliation(s)
- Kimberly K Amrami
- Division of Body Magnetic Resonance Imaging, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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Stewart EA, Taran FA, Chen J, Gostout BS, Woodrum DA, Felmlee JP, Ehman RL. Magnetic resonance elastography of uterine leiomyomas: a feasibility study. Fertil Steril 2010; 95:281-4. [PMID: 20633880 DOI: 10.1016/j.fertnstert.2010.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 04/06/2010] [Accepted: 06/02/2010] [Indexed: 10/19/2022]
Abstract
OBJECTIVE To determine the feasibility of performing in vivo magnetic resonance elastography (MRE) for uterine leiomyoma. DESIGN Pilot study. SETTING Academic medical center. PATIENT(S) Six subjects planning surgical excision of uterine leiomyomas. INTERVENTION(S) MRE before planned surgery. MAIN OUTCOME MEASURE(S) Achieving an appropriate phase signal-to-noise ratio (PSNR) in the leiomyoma to allow assessment of leiomyoma elasticity in kilopascals (kPa). RESULT(S) MRE was successful in all subjects for uteri ranging from 100 to >1,000 g. Subjects had body mass indexes ranging from 23.0 to 38.0 kg/m2. Appropriate PSNRs, ranging from 5.45 to 42.28, were achieved for leiomyomas in all subjects. Mean elasticity of uterine leiomyomas ranged from 3.95 to 6.68 kPa. CONCLUSION(S) MRE is a feasible technique for studying the in vivo mechanical properties of uterine leiomyomas and demonstrates significant heterogeneity in elasticity between lesions. Further work is necessary to optimize the technique and understand the clinical utility of this technique for women with uterine leiomyomas.
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Affiliation(s)
- Elizabeth A Stewart
- Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, Minnesota 55905, USA.
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