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Zubair AS, Salam S, Dimachkie MM, Machado PM, Roy B. Imaging biomarkers in the idiopathic inflammatory myopathies. Front Neurol 2023; 14:1146015. [PMID: 37181575 PMCID: PMC10166883 DOI: 10.3389/fneur.2023.1146015] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/03/2023] [Indexed: 05/16/2023] Open
Abstract
Idiopathic inflammatory myopathies (IIMs) are a group of acquired muscle diseases with muscle inflammation, weakness, and other extra-muscular manifestations. IIMs can significantly impact the quality of life, and management of IIMs often requires a multi-disciplinary approach. Imaging biomarkers have become an integral part of the management of IIMs. Magnetic resonance imaging (MRI), muscle ultrasound, electrical impedance myography (EIM), and positron emission tomography (PET) are the most widely used imaging technologies in IIMs. They can help make the diagnosis and assess the burden of muscle damage and treatment response. MRI is the most widely used imaging biomarker of IIMs and can assess a large volume of muscle tissue but is limited by availability and cost. Muscle ultrasound and EIM are easy to administer and can even be performed in the clinical setting, but they need further validation. These technologies may complement muscle strength testing and laboratory studies and provide an objective assessment of muscle health in IIMs. Furthermore, this is a rapidly progressing field, and new advances are going to equip care providers with a better objective assessment of IIMS and eventually improve patient management. This review discusses the current state and future direction of imaging biomarkers in IIMs.
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Affiliation(s)
- Adeel S. Zubair
- Division of Neuromuscular Diseases, Department of Neurology, Yale University School of Medicine, New Haven, CT, United States
| | - Sharfaraz Salam
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Mazen M. Dimachkie
- Department of Neurology, The University of Kansas Medical Center, Kansas City, KS, United States
| | - Pedro M. Machado
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Centre for Rheumatology, Division of Medicine, University College London, London, United Kingdom
| | - Bhaskar Roy
- Division of Neuromuscular Diseases, Department of Neurology, Yale University School of Medicine, New Haven, CT, United States
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Statland JM, Heatwole C, Eichinger K, Dilek N, Martens WB, Tawil R. Electrical impedance myography in facioscapulohumeral muscular dystrophy. Muscle Nerve 2016; 54:696-701. [PMID: 26840230 DOI: 10.1002/mus.25065] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/24/2016] [Accepted: 01/28/2016] [Indexed: 12/14/2022]
Abstract
INTRODUCTION In this study we determined the reliability and validity of electrical impedance myography (EIM) in facioscapulohumeral muscular dystrophy (FSHD). METHODS We performed a prospective study of EIM on 16 bilateral limb and trunk muscles in 35 genetically defined and clinically affected FSHD patients (reliability testing on 18 patients). Summary scores based on body region were derived. Reactance and phase (50 and 100 kHz) were compared with measures of strength, FSHD disease severity, and functional outcomes. RESULTS Participants were mostly men, mean age 53.0 years, and included a full range of severity. Limb and trunk muscles showed good to excellent reliability [intraclass correlation coefficients (ICC) 0.72-0.99]. Summary scores for the arm, leg, and trunk showed excellent reliability (ICC 0.89-0.98). Reactance was the most sensitive EIM parameter to a broad range of FSHD disease metrics. CONCLUSIONS EIM is a reliable measure of muscle composition in FSHD that offers the possibility to serially evaluate affected muscles. Muscle Nerve 54: 696-701, 2016.
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Affiliation(s)
- Jeffrey M Statland
- Department of Neurology, University of Kansas Medical Center, 4330 Shawnee Mission Parkway, Ste. 323, Fairway, Kansas, 66205, USA.
| | - Chad Heatwole
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - Katy Eichinger
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - Nuran Dilek
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - William B Martens
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - Rabi Tawil
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
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Turner MR, Bowser R, Bruijn L, Dupuis L, Ludolph A, McGrath M, Manfredi G, Maragakis N, Miller RG, Pullman SL, Rutkove SB, Shaw PJ, Shefner J, Fischbeck KH. Mechanisms, models and biomarkers in amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2013; 14 Suppl 1:19-32. [PMID: 23678877 DOI: 10.3109/21678421.2013.778554] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The last 30 years have seen a major advance in the understanding of the clinical and pathological heterogeneity of amyotrophic lateral sclerosis (ALS), and its overlap with frontotemporal dementia. Multiple, seemingly disparate biochemical pathways converge on a common clinical syndrome characterized by progressive loss of upper and lower motor neurons. Pathogenic themes in ALS include excitotoxicity, oxidative stress, mitochondrial dysfunction, neuroinflammation, altered energy metabolism, and most recently RNA mis-processing. The transgenic rodent, overexpressing mutant superoxide dismutase-1, is now only one of several models of ALS pathogenesis. The nematode, fruit fly and zebrafish all offer fresh insight, and the development of induced pluripotent stem cell-derived motor neurons holds promise for the screening of candidate therapeutics. The lack of useful biomarkers in ALS contributes to diagnostic delay, and the inability to stratify patients by prognosis may be an important factor in the failure of therapeutic trials. Biomarkers sensitive to disease activity might lessen reliance on clinical measures and survival as trial endpoints and reduce study length. Emerging proteomic markers of neuronal loss and glial activity in cerebrospinal fluid, a cortical signature derived from advanced structural and functional MRI, and the development of more sensitive measurements of lower motor neuron physiology are leading a new phase of biomarker-driven therapeutic discovery.
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Affiliation(s)
- Martin R Turner
- Nuffield Department of Clinical Neurosciences, University of Oxford, UK.
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Li J, Spieker AJ, Rosen GD, Rutkove SB. Electrical impedance alterations in the rat hind limb with unloading. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2013; 13:37-44. [PMID: 23445913 PMCID: PMC3984464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVES Methods are needed for quantifying muscle deconditioning due to immobilization, aging, or spaceflight. Electrical impedance myography (EIM) is one technique that may offer easy-to-follow metrics. Here, we evaluate the time course and character of the change in single- and multi-frequency EIM parameters in the hind-limb suspension model of muscle deconditioning in rats. METHODS Sixty-two rats were studied with EIM during a two-week period of hind limb unloading followed by a two-week recovery period. Random subsets of animals were sacrificed at one-week time intervals to measure muscle fiber size. RESULTS Significant alterations were observed in nearly all impedance parameters. The 50 kHz phase and multi-frequency phase-slope, created by taking the slope of a line fitted to the impedance values between 100-500 kHz, appeared most sensitive to disuse atrophy, the latter decreasing by over 33.0±6.6% (p<0.001), a change similar to the maximum reduction in muscle fiber size. Impedance alterations, however, lagged changes in muscle fiber size. CONCLUSIONS EIM is sensitive to disuse change in the rat, albeit with a delay relative to alterations in muscle fiber size. Given the rapidity and simplicity of EIM measurements, the technique could prove useful in providing a non-invasive approach to measuring disuse change in animal models and human subjects.
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Affiliation(s)
- J Li
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School,USA
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Rutkove SB, Caress JB, Cartwright MS, Burns TM, Warder J, David WS, Goyal N, Maragakis NJ, Clawson L, Benatar M, Usher S, Sharma KR, Gautam S, Narayanaswami P, Raynor EM, Watson ML, Shefner JM. Electrical impedance myography as a biomarker to assess ALS progression. ACTA ACUST UNITED AC 2012; 13:439-45. [PMID: 22670883 DOI: 10.3109/17482968.2012.688837] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Electrical impedance myography (EIM), a non-invasive, electrophysiological technique, has preliminarily shown value as an ALS biomarker. Here we perform a multicenter study to further assess EIM's potential for tracking ALS. ALS patients were enrolled across eight sites. Each subject underwent EIM, handheld dynamometry (HHD), and the ALS Functional Rating Scale-revised (ALSFRS-R) regularly. Techniques were compared by assessing the coefficient of variation (CoV) in the rate of decline and each technique's correlation to survival. Results showed that in the 60 patients followed for one year, EIM phase measured from the most rapidly progressing muscle in each patient had a CoV in the rate of decline of 0.62, compared to HHD (0.82) and the ALSFRS-R (0.74). Restricting the measurements to the first six months gave a CoV of 0.55 for EIM, 0.93 for HHD, and 0.84 for ALSFRS-R. For both time-periods, all three measures correlated with survival. Based on these data, a six-month clinical trial designed to detect a 20% treatment effect with 80% power using EIM would require only 95 patients/arm compared to the ALSFRS-R, which would require 220 subjects/arm. In conclusion, EIM can serve as a useful ALS biomarker that offers the prospect of greatly accelerating phase 2 clinical trials.
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Affiliation(s)
- Seward B Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA.
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Rutkove SB, Gregas MC, Darras BT. Electrical impedance myography in spinal muscular atrophy: a longitudinal study. Muscle Nerve 2012; 45:642-7. [PMID: 22499089 DOI: 10.1002/mus.23233] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
INTRODUCTION New approaches for assessing disease progression in spinal muscular atrophy (SMA) are needed. In this study, we evaluate whether electrical impedance myography (EIM) can detect disease progression in SMA compared with a group of healthy children of similar age. METHODS Twenty-eight children with SMA and 20 normal children underwent repeated EIM testing in four muscles at regular intervals for up to 3 years. An average rate of change of EIM was calculated for each subject and normalized to subcutaneous fat thickness and muscle girth. RESULTS Multiple EIM parameters showed a change in normal subjects over a mean of 16.7 months; however, no change was found in SMA patients over this period. CONCLUSIONS EIM could detect non-mass-dependent muscle maturation in healthy children. In contrast, the muscle in children with SMA, as measured by EIM, was virtually static, showing no evidence of growth or active deterioration.
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Affiliation(s)
- Seward B Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, Massachusetts 02215, USA.
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Wang LL, Spieker AJ, Li J, Rutkove SB. Electrical impedance myography for monitoring motor neuron loss in the SOD1 G93A amyotrophic lateral sclerosis rat. Clin Neurophysiol 2011; 122:2505-11. [PMID: 21612980 DOI: 10.1016/j.clinph.2011.04.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 04/04/2011] [Accepted: 04/26/2011] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Human studies have shown that electrical impedance myography (EIM), a technique based on the surface application of high-frequency, low-intensity electrical current to localized areas of muscle, is sensitive to muscle denervation. In this study, we examined the role of EIM as a potential biomarker for assessing ALS disease progression in the SOD1 transgenic rat by comparing it to motor unit number estimation (MUNE). METHODS Multi-frequency EIM and MUNE were performed twice weekly in 16 rats from approximately 10 weeks of age onward. Four different EIM measures were evaluated, including the previously studied 50 kHz phase and three condensed multi-frequency parameters. RESULTS The rate of deterioration in the multi-frequency phase data from 100-500 kHz had the strongest correlation to survival (ρ=0.79, p<0.001), surpassing that of MUNE (ρ=0.57, p=0.020). These two measures were also strongly correlated (ρ=-0.94, p<0.001) to one another. CONCLUSIONS These findings support that EIM is an effective tool for assessing disease progression in the ALS rat. SIGNIFICANCE Given its ease of application and ability to assess virtually any superficial muscle, EIM deserves further study as a biomarker in human ALS clinical therapeutic trials.
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Affiliation(s)
- Lucy Lu Wang
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
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Wang LL, Ahad M, McEwan A, Li J, Jafarpoor M, Rutkove SB. Assessment of alterations in the electrical impedance of muscle after experimental nerve injury via finite-element analysis. IEEE Trans Biomed Eng 2011; 58:1585-91. [PMID: 21224171 DOI: 10.1109/tbme.2011.2104957] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The surface measurement of electrical impedance of muscle, incorporated as the technique of electrical impedance myography (EIM), provides a noninvasive approach for evaluating neuromuscular diseases, including amyotrophic lateral sclerosis. However, the relationship between alterations in surface impedance and the electrical properties of muscle remains uncertain. In order to investigate this further, a group of healthy adult rats, a group of rats two weeks postsciatic crush, and a group of animals six months postcrush underwent EIM of the gastrocnemius-soleus complex. The animals were then killed and the conductivity and permittivity of the extracted muscle measured. Finite-element models based on MRI data were then constructed for each group. The characteristic EIM parameter, 50 kHz phase (±standard error), obtained with surface impedance measurements was 17.3° ± 0.3° for normal animals, 13.8° ± 0.7° for acutely injured animals, and 16.1° ± 0.5° for chronically injured animals. The models predicted parallel changes with phase values of 24.3°, 18.8°, and 21.2° for the normal, acute, and chronic groups, respectively. Other multifrequency impedance parameters showed similar alterations. These results confirm that surface impedance measurements taken in conjunction with anatomical data and finite-element models may offer a noninvasive approach for assessing biophysical alterations in muscle in neuromuscular disease states.
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Affiliation(s)
- Lucy L Wang
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
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