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Makino Y, Kojima M, Yoshida M, Motomura A, Inokuchi G, Chiba F, Torimitsu S, Hoshioka Y, Yamaguchi R, Saito N, Urabe S, Tsuneya S, Horikoshi T, Yajima D, Iwase H. Postmortem CT and MRI findings of massive fat embolism. Int J Legal Med 2019; 134:669-678. [PMID: 31375910 DOI: 10.1007/s00414-019-02128-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 07/26/2019] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To elucidate postmortem computed tomography (PMCT) and postmortem magnetic resonance (PMMR) imaging findings suggesting massive fat embolism. MATERIALS AND METHODS Consecutive forensic cases with PMCT and PMMR scans of subjects prior to autopsy were assessed. For PMCT, 16- or 64-row multidetector CT scans were used; for PMMR, a 1.5 T system was used. MRI sequences of the chest area included T2- and T1-weighted fast spin-echo imaging, T2*-weighted imaging, T1-weighted 3-dimensional gradient-echo imaging with or without a fat-suppression pulse, short tau inversion recovery, and in-phase/opposed-phase imaging. At autopsy, forensic pathologists checked for pulmonary fat embolism with fat staining; Falzi's grading system was used for classification. RESULTS Of 31 subjects, four were excluded because fat staining for histopathological examination of the lung tissue could not be performed. In three of the remaining 27 subjects, histology revealed massive fat embolism (Falzi grade III) and the cause of death was considered to be associated with fat embolism. CT detected a "fat-fluid level" in the right heart or intraluminal fat in the pulmonary arterial branches in two subjects. MRI detected these findings more clearly in both subjects. In one subject, CT and MRI were both negative. There were no positive findings in the 24 subjects that were fat embolism-negative by histology. DISCUSSION AND CONCLUSION In some subjects, a massive fat embolism can be suggested by postmortem imaging with a "fat-fluid level" in the right heart or intraluminal fat in the pulmonary arterial branches. PMMR potentially suggests fat embolism more clearly than PMCT.
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Affiliation(s)
- Yohsuke Makino
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. .,Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
| | - Masatoshi Kojima
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | - Maiko Yoshida
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | - Ayumi Motomura
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.,Department of Forensic Medicine, School of Medicine, International University of Health and Welfare, 4-3 Kozunomori, Narita, 286-8686, Japan
| | - Go Inokuchi
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | - Fumiko Chiba
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | - Suguru Torimitsu
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | - Yumi Hoshioka
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | - Rutsuko Yamaguchi
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | - Naoki Saito
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | - Shumari Urabe
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | - Shigeki Tsuneya
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Takuro Horikoshi
- Department of Radiology, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8677, Japan
| | - Daisuke Yajima
- Department of Forensic Medicine, School of Medicine, International University of Health and Welfare, 4-3 Kozunomori, Narita, 286-8686, Japan
| | - Hirotaro Iwase
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
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Goceri E, Shah ZK, Layman R, Jiang X, Gurcan MN. Quantification of liver fat: A comprehensive review. Comput Biol Med 2016; 71:174-89. [PMID: 26945465 DOI: 10.1016/j.compbiomed.2016.02.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 12/19/2022]
Abstract
Fat accumulation in the liver causes metabolic diseases such as obesity, hypertension, diabetes or dyslipidemia by affecting insulin resistance, and increasing the risk of cardiac complications and cardiovascular disease mortality. Fatty liver diseases are often reversible in their early stage; therefore, there is a recognized need to detect their presence and to assess its severity to recognize fat-related functional abnormalities in the liver. This is crucial in evaluating living liver donors prior to transplantation because fat content in the liver can change liver regeneration in the recipient and donor. There are several methods to diagnose fatty liver, measure the amount of fat, and to classify and stage liver diseases (e.g. hepatic steatosis, steatohepatitis, fibrosis and cirrhosis): biopsy (the gold-standard procedure), clinical (medical physics based) and image analysis (semi or fully automated approaches). Liver biopsy has many drawbacks: it is invasive, inappropriate for monitoring (i.e., repeated evaluation), and assessment of steatosis is somewhat subjective. Qualitative biomarkers are mostly insufficient for accurate detection since fat has to be quantified by a varying threshold to measure disease severity. Therefore, a quantitative biomarker is required for detection of steatosis, accurate measurement of severity of diseases, clinical decision-making, prognosis and longitudinal monitoring of therapy. This study presents a comprehensive review of both clinical and automated image analysis based approaches to quantify liver fat and evaluate fatty liver diseases from different medical imaging modalities.
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Affiliation(s)
- Evgin Goceri
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, USA.
| | - Zarine K Shah
- Department of Radiology, Wexner Medical Center, The Ohio State University, Columbus, USA
| | - Rick Layman
- Department of Radiology, Wexner Medical Center, The Ohio State University, Columbus, USA
| | - Xia Jiang
- Department of Radiology, Wexner Medical Center, The Ohio State University, Columbus, USA
| | - Metin N Gurcan
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, USA
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3
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Hussein MO, Hoad CL, Stephenson MC, Cox EF, Placidi E, Pritchard SE, Costigan C, Ribeiro H, Ciampi E, Rayment P, Nandi A, Hedges N, Sanderson P, Peters HP, Kruse I, Marciani L, Spiller RC, Gowland PA. Magnetic resonance spectroscopy measurements of intragastric fat fraction of oil emulsions in humans. EUR J LIPID SCI TECH 2014. [DOI: 10.1002/ejlt.201400058] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mahamoud O. Hussein
- Sir Peter Mansfield Magnetic Resonance Centre; School of Physics and Astronomy; University of Nottingham; Nottingham UK
| | - Caroline L. Hoad
- Sir Peter Mansfield Magnetic Resonance Centre; School of Physics and Astronomy; University of Nottingham; Nottingham UK
| | - Mary C. Stephenson
- Sir Peter Mansfield Magnetic Resonance Centre; School of Physics and Astronomy; University of Nottingham; Nottingham UK
| | - Eleanor F. Cox
- Sir Peter Mansfield Magnetic Resonance Centre; School of Physics and Astronomy; University of Nottingham; Nottingham UK
| | - Elisa Placidi
- Sir Peter Mansfield Magnetic Resonance Centre; School of Physics and Astronomy; University of Nottingham; Nottingham UK
| | - Susan E. Pritchard
- Sir Peter Mansfield Magnetic Resonance Centre; School of Physics and Astronomy; University of Nottingham; Nottingham UK
| | - Carolyn Costigan
- Sir Peter Mansfield Magnetic Resonance Centre; School of Physics and Astronomy; University of Nottingham; Nottingham UK
| | | | | | - Pip Rayment
- Unilever Discover; Colworth Science Park; Sharnbrook UK
| | - Asish Nandi
- Unilever Discover; Colworth Science Park; Sharnbrook UK
| | - Nick Hedges
- Unilever Discover; Colworth Science Park; Sharnbrook UK
| | | | | | - Irmela Kruse
- Unilever Discover; Colworth Science Park; Sharnbrook UK
| | - Luca Marciani
- Nottingham Digestive Diseases Centre and Nottingham Digestive Diseases Biomedical Research Unit; University of Nottingham; Nottingham UK
| | - Robin C. Spiller
- Nottingham Digestive Diseases Centre and Nottingham Digestive Diseases Biomedical Research Unit; University of Nottingham; Nottingham UK
| | - Penny A. Gowland
- Sir Peter Mansfield Magnetic Resonance Centre; School of Physics and Astronomy; University of Nottingham; Nottingham UK
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4
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Just Kukurova I, Valkovič L, Bogner W, Gajdošík M, Krššák M, Gruber S, Trattnig S, Chmelík M. Two-dimensional spectroscopic imaging with combined free induction decay and long-TE acquisition (FID echo spectroscopic imaging, FIDESI) for the detection of intramyocellular lipids in calf muscle at 7 T. NMR IN BIOMEDICINE 2014; 27:980-987. [PMID: 24912448 DOI: 10.1002/nbm.3148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 05/08/2014] [Accepted: 05/08/2014] [Indexed: 06/03/2023]
Abstract
The aim of this study was to introduce a two-dimensional chemical shift imaging (2D CSI) sequence, with simultaneous acquisition of free induction decay (FID) and long TEs, for the detection and quantification of intramyocellular lipids (IMCLs) in the calf at 7 T. The feasibility of the new 2D CSI sequence, which acquires FID (acquisition delay, 1.3 ms) and an echo (long TE) in one measurement, was evaluated in phantoms and volunteers (n = 5): TR/TE*/TE = 800/1.3/156 ms; 48 × 48 matrix; field of view, 200 × 200 × 20 mm(3) ; Hamming filter; no water suppression; measurement time, 22 min 2 s. The IMCL concentration and subcutaneous lipid contamination were assessed. Spectra in the tibialis anterior (TA), gastrocnemius (GM) and soleus (SOL) muscles were analyzed. The water signal from the FID acquisition was used as an internal concentration reference. In the spectra from subcutaneous adipose tissue (SUB) and bone marrow (BM), an unsaturation index (UI) of the vinyl-H (5.3 ppm) to methyl-CH3 ratio, and a polyunsaturation index (pUI) of the diallylic-H (2.77 ppm) to -CH3 ratio, were calculated. Long-TE spectra from muscles showed a simplified spectral pattern with well-separated IMCL for several muscle groups in the same scan. The IMCL to water ratio was largest in SOL (0.66% ± 0.23%), and lower in GM (0.37% ± 0.14%) and TA (0.36% ± 0.12%). UI and pUI for SUB were 0.65 ± 0.06 and 0.18 ± 0.04, respectively, and for BM were 0.60 ± 0.16 and 0.18 ± 0.08, respectively. The new sequence, with the proposed name 'free induction decay echo spectroscopic imaging' (FIDESI), provides information on both specific lipid resonances and water signal from different tissues in the calf, with high spectral and spatial resolution, as well as minimal voxel bleeding and subcutaneous lipid contamination, in clinically acceptable measurement times.
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Affiliation(s)
- Ivica Just Kukurova
- MR Centre of Excellence, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Department of NMR and MS, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovakia
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5
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Harry H, Kan HE. Quantitative proton MR techniques for measuring fat. NMR IN BIOMEDICINE 2013; 26:1609-29. [PMID: 24123229 PMCID: PMC4001818 DOI: 10.1002/nbm.3025] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 07/13/2013] [Accepted: 08/19/2013] [Indexed: 05/09/2023]
Abstract
Accurate, precise and reliable techniques for the quantification of body and organ fat distributions are important tools in physiology research. They are critically needed in studies of obesity and diseases involving excess fat accumulation. Proton MR methods address this need by providing an array of relaxometry-based (T1, T2) and chemical shift-based approaches. These techniques can generate informative visualizations of regional and whole-body fat distributions, yield measurements of fat volumes within specific body depots and quantify fat accumulation in abdominal organs and muscles. MR methods are commonly used to investigate the role of fat in nutrition and metabolism, to measure the efficacy of short- and long-term dietary and exercise interventions, to study the implications of fat in organ steatosis and muscular dystrophies and to elucidate pathophysiological mechanisms in the context of obesity and its comorbidities. The purpose of this review is to provide a summary of mainstream MR strategies for fat quantification. The article succinctly describes the principles that differentiate water and fat proton signals, summarizes the advantages and limitations of various techniques and offers a few illustrative examples. The article also highlights recent efforts in the MR of brown adipose tissue and concludes by briefly discussing some future research directions.
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Affiliation(s)
- Houchun Harry
- Corresponding Author Houchun Harry Hu, PhD Children's Hospital Los Angeles University of Southern California 4650 Sunset Boulevard Department of Radiology, MS #81 Los Angeles, California, USA. 90027 , Office: +1 (323) 361-2688 Fax: +1 (323) 361-1510
| | - Hermien E. Kan
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
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6
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Vermathen P, Saillen P, Boss A, Zehnder M, Boesch C. Skeletal muscle ¹H MRSI before and after prolonged exercise. I. muscle specific depletion of intramyocellular lipids. Magn Reson Med 2012; 68:1357-67. [PMID: 22287260 DOI: 10.1002/mrm.24168] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 11/29/2011] [Accepted: 12/27/2011] [Indexed: 12/25/2022]
Abstract
Aim of the study was to determine distribution and depletion patterns of intramyocellular lipids (IMCL) in leg muscles before and after two types of standardized endurance exercise. ¹H-magnetic resonance spectroscopic imaging was performed (1) in the thigh of eight-trained cyclists after exercising on an ergometer for 3 h at 52 ± 8% of maximal speed and (2) in the lower leg of eight-trained runners after exercising on a treadmill for 3 h at 49 ± 3% of maximal workload. Pre-exercise IMCL contents were reduced postexercise in 11 out of 13 investigated upper and lower leg muscles (P < 0.015 for all). A strong linear correlation with a slope of ∼0.5 between pre-exercise IMCL content and IMCL depletion was found. IMCL depletion differed strongly between muscles. Absolute and also relative IMCL reduction was significantly higher in muscles with predominantly slow fibers compared to those with fast fibers. Creatine levels and fiber orientation were stable and unchanged after exercise, while trimethyl-ammonium groups increased. This is presented in the accompanying paper. In conclusion, a systematic comparison of metabolic changes in cross sections of the upper and lower leg was performed. The results imply that pre-exercise IMCL levels determine the degree of IMCL depletion after exercise.
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Affiliation(s)
- Peter Vermathen
- Department of Clinical Research, University and Inselspital Berne, Switzerland.
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7
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Karampinos DC, Yu H, Shimakawa A, Link TM, Majumdar S. T₁-corrected fat quantification using chemical shift-based water/fat separation: application to skeletal muscle. Magn Reson Med 2011; 66:1312-26. [PMID: 21452279 PMCID: PMC3150641 DOI: 10.1002/mrm.22925] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 01/25/2011] [Accepted: 02/21/2011] [Indexed: 12/11/2022]
Abstract
Chemical shift-based water/fat separation, like iterative decomposition of water and fat with echo asymmetry and least-squares estimation, has been proposed for quantifying intermuscular adipose tissue. An important confounding factor in iterative decomposition of water and fat with echo asymmetry and least-squares estimation-based intermuscular adipose tissue quantification is the large difference in T(1) between muscle and fat, which can cause significant overestimation in the fat fraction. This T(1) bias effect is usually reduced by using small flip angles. T(1) -correction can be performed by using at least two different flip angles and fitting for T(1) of water and fat. In this work, a novel approach for the water/fat separation problem in a dual flip angle experiment is introduced and a new approach for the selection of the two flip angles, labeled as the unequal small flip angle approach, is developed, aiming to improve the noise efficiency of the T(1) -correction step relative to existing approaches. It is shown that the use of flip angles, selected such the muscle water signal is assumed to be T(1) -independent for the first flip angle and the fat signal is assumed to be T(1) -independent for the second flip angle, has superior noise performance to the use of equal small flip angles (no T(1) estimation required) and the use of large flip angles (T(1) estimation required).
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Affiliation(s)
- Dimitrios C Karampinos
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.
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8
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Abstract
As the prevalence of obesity continues to rise, rapid and accurate tools for assessing abdominal body and organ fat quantity and distribution are critically needed to assist researchers investigating therapeutic and preventive measures against obesity and its comorbidities. Magnetic resonance imaging (MRI) is the most promising modality to address such need. It is non-invasive, utilizes no ionizing radiation, provides unmatched 3-D visualization, is repeatable, and is applicable to subject cohorts of all ages. This article is aimed to provide the reader with an overview of current and state-of-the-art techniques in MRI and associated image analysis methods for fat quantification. The principles underlying traditional approaches such as T(1) -weighted imaging and magnetic resonance spectroscopy as well as more modern chemical-shift imaging techniques are discussed and compared. The benefits of contiguous 3-D acquisitions over 2-D multislice approaches are highlighted. Typical post-processing procedures for extracting adipose tissue depot volumes and percent organ fat content from abdominal MRI data sets are explained. Furthermore, the advantages and disadvantages of each MRI approach with respect to imaging parameters, spatial resolution, subject motion, scan time and appropriate fat quantitative endpoints are also provided. Practical considerations in implementing these methods are also presented.
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Affiliation(s)
- H H Hu
- Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA.
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De Santis S, Rebuzzi M, Di Pietro G, Fasano F, Maraviglia B, Capuani S. In vitroandin vivoMR evaluation of internal gradient to assess trabecular bone density. Phys Med Biol 2010; 55:5767-85. [DOI: 10.1088/0031-9155/55/19/010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Ortiz-Nieto F, Johansson L, Ahlström H, Weis J. Quantification of lipids in human lower limbs using yellow bone marrow as the internal reference: gender-related effects. Magn Reson Imaging 2010; 28:676-82. [PMID: 20395098 DOI: 10.1016/j.mri.2010.03.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 03/04/2010] [Accepted: 03/05/2010] [Indexed: 01/06/2023]
Abstract
The main purpose of this study was to determine and compare extra- and intramyocellular (IMCL) lipids content in the calf and thigh muscles of normal male and female volunteers using high-spatial-resolution magnetic resonance spectroscopic imaging (MRSI). The study groups consisted of 10 females and 10 males. The subjects were healthy and normal-weight. Fat (yellow bone marrow) was used as the internal concentration reference. Total fat and IMCL content were computed for all muscles in the slice and for three muscle compartments in the thigh, whereas three muscles and three muscle compartments were evaluated in the calf. To avoid the confounding effects of physical activity and diet, measurements were performed in the same session. A common feature for both genders was that thigh muscles had approximately 2.5 times greater total fat content as compared to muscles of the calf. The mean IMCL level was, however, more than 3 times higher in the calf muscles compared with the thigh. No significant differences in lipid concentrations of correspondent regions of interest were found between genders. The high-spatial-resolution MRSI technique enables a more detailed study of muscle lipid distribution and can therefore improve understanding of muscle lipid metabolism in healthy volunteers and in studies of patients with metabolic disorders.
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Lang T, Streeper T, Cawthon P, Baldwin K, Taaffe DR, Harris TB. Sarcopenia: etiology, clinical consequences, intervention, and assessment. Osteoporos Int 2010; 21:543-59. [PMID: 19779761 PMCID: PMC2832869 DOI: 10.1007/s00198-009-1059-y] [Citation(s) in RCA: 469] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2009] [Accepted: 08/18/2009] [Indexed: 02/07/2023]
Abstract
The aging process is associated with loss of muscle mass and strength and decline in physical functioning. The term sarcopenia is primarily defined as low level of muscle mass resulting from age-related muscle loss, but its definition is often broadened to include the underlying cellular processes involved in skeletal muscle loss as well as their clinical manifestations. The underlying cellular changes involve weakening of factors promoting muscle anabolism and increased expression of inflammatory factors and other agents which contribute to skeletal muscle catabolism. At the cellular level, these molecular processes are manifested in a loss of muscle fiber cross-sectional area, loss of innervation, and adaptive changes in the proportions of slow and fast motor units in muscle tissue. Ultimately, these alterations translate to bulk changes in muscle mass, strength, and function which lead to reduced physical performance, disability, increased risk of fall-related injury, and, often, frailty. In this review, we summarize current understanding of the mechanisms underlying sarcopenia and age-related changes in muscle tissue morphology and function. We also discuss the resulting long-term outcomes in terms of loss of function, which causes increased risk of musculoskeletal injuries and other morbidities, leading to frailty and loss of independence.
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Affiliation(s)
- T Lang
- Department of Radiology and Biomedical Imaging, University of California, UCSF, San Francisco, CA 94143-0946, USA.
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van der Graaf M, Tack CJ, de Haan JH, Klomp DWJ, Heerschap A. Magnetic resonance spectroscopy shows an inverse correlation between intramyocellular lipid content in human calf muscle and local glycogen synthesis rate. NMR IN BIOMEDICINE 2010; 23:133-141. [PMID: 19739109 DOI: 10.1002/nbm.1433] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Intramyocellular lipid (IMCL) content of skeletal muscle, as measured with (1)H MRS, is inversely correlated with insulin sensitivity as determined by whole body glucose uptake. The latter, however, does not necessarily represent the actual glucose uptake in the corresponding skeletal muscle. In this study, we examined whether IMCL content in human calf muscle correlated with local glucose uptake assessed by measurement of glycogen synthesis rate within the same muscle compartment. We studied 20 subjects belonging to four subgroups of five persons each: young lean, elderly lean, young obese and elderly obese. IMCL content in the soleus and gastrocnemius muscle was determined using (1)H MR spectroscopic imaging and local glycogen synthesis rate in the calf muscle was measured by (13)C MRS during a euglycaemic hyperinsulinaemic clamp with 20% w/v 30% (13)C-1-labelled glucose infusion. Significantly higher IMCL contents were found in elderly (soleus: p < 0.0001 and gastrocnemius: p < 0.01) and obese subjects (p < 0.01 for both muscles). Local glycogen synthesis rate decreased significantly with obesity (p < 0.01). The principal finding of this study was that the mean IMCL content of the soleus and gastrocnemius muscles was indeed inversely correlated with the local glycogen synthesis rate in the calf muscle (r(s) = -0.50, p < 0.05), with a very similar dependency as the inverse correlation between mean IMCL content and total body glucose uptake (r(s) = -0.54, p < 0.05). We conclude that IMCL content of the soleus and gastrocnemius muscles reflects a measure for local insulin resistance within the same muscle compartment as determined by glycogen synthesis rate. Although the inverse correlation suggests that insulin sensitivity is affected by the local amount of fat present, it remains to be determined if this is a cause or a consequence.
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Affiliation(s)
- Marinette van der Graaf
- Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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Weis J, Johansson L, Ortiz-Nieto F, Ahlström H. Assessment of lipids in skeletal muscle by LCModel and AMARES. J Magn Reson Imaging 2010; 30:1124-9. [PMID: 19780186 DOI: 10.1002/jmri.21900] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
PURPOSE To process single voxel spectra of the human skeletal muscle by using an advanced method for accurate, robust, and efficient spectral fitting (AMARES) and by linear combination of model spectra (LCModel). To determine absolute concentrations of extra- (EMCL) and intramyocellular lipids (IMCL). MATERIALS AND METHODS Single-voxel proton magnetic resonance spectroscopy (PRESS) was used to obtain the spectra of the calf muscles. Unsuppressed water line was used as a concentration reference. A new prior knowledge for AMARES was proposed to estimate the concentrations of EMCL and IMCL. The prior knowledge was derived from the spectrum of vegetable oil. The results were compared with the values estimated by LCModel. Absolute concentrations of total lipid content in millimoles per kilogram wet weight were used for the comparisons. RESULTS Absolute concentrations of total lipid content in skeletal muscle were estimated by AMARES and LCModel. Very good correlation of the total fat (EMCL + IMCL) and IMCL concentrations was achieved between both data processing approaches. CONCLUSION Assessment the absolute concentrations of muscular lipids by AMARES and LCModel can be performed with comparable accuracy.
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Affiliation(s)
- Jan Weis
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden.
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14
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Hu HH, Nayak KS. Quantification of absolute fat mass using an adipose tissue reference signal model. J Magn Reson Imaging 2009; 28:1483-91. [PMID: 19025936 PMCID: PMC2732124 DOI: 10.1002/jmri.21603] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PURPOSE To develop a method for quantifying absolute fat mass, and to demonstrate its feasibility in phantoms and in ex vivo swine specimens at 3 Tesla. MATERIALS AND METHODS Chemical-shift-based fat-water decomposition was used to first reconstruct fat-only images. Our proposed model used a reference signal from fat in pure adipose tissue to calibrate and normalize the fat signal intensities from the fat-only images. Fat mass was subsequently computed on a voxel-by-voxel basis and summed across each sample. Feasibility of the model was tested in six ex vivo swine samples containing varying mixtures of fat (adipose) and lean tissues. The samples were imaged using 1.5-mm isotropic voxels and a single-channel birdcage head coil at 3 Tesla. Lipid assay was independently performed to determine fat mass, and served as the comparison standard. RESULTS Absolute fat mass values (in grams) derived by our proposed model were in excellent agreement with lipid assay results, with a 5% to 7% difference (r > 0.99; P < 0.001). CONCLUSION Preliminary results in ex vivo swine samples demonstrated the feasibility of computing absolute fat mass as a quantitative endpoint using chemical-shift fat-water MRI with a signal model based on reference fat from pure adipose tissue.
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Affiliation(s)
- Houchun H Hu
- Magnetic Resonance Engineering Laboratory, Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089-2564, USA.
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Ren J, Dimitrov I, Sherry AD, Malloy CR. Composition of adipose tissue and marrow fat in humans by 1H NMR at 7 Tesla. J Lipid Res 2008; 49:2055-62. [PMID: 18509197 PMCID: PMC2515528 DOI: 10.1194/jlr.d800010-jlr200] [Citation(s) in RCA: 292] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Proton NMR spectroscopy at 7 Tesla (7T) was evaluated as a new method to quantify human fat composition noninvasively. In validation experiments, the composition of a known mixture of triolein, tristearin, and trilinolein agreed well with measurements by 1H NMR spectroscopy. Triglycerides in calf subcutaneous tissue and tibial bone marrow were examined in 20 healthy subjects by 1H spectroscopy. Ten well-resolved proton resonances from triglycerides were detected using stimulated echo acquisition mode sequence and small voxel (∼0.1 ml), and T1 and T2 were measured. Triglyceride composition was not different between calf subcutaneous adipose tissue and tibial marrow for a given subject, and its variation among subjects, as a result of diet and genetic differences, fell in a narrow range. After correction for differential relaxation effects, the marrow fat composition was 29.1 ± 3.5% saturated, 46.4 ± 4.8% monounsaturated, and 24.5 ± 3.1% diunsaturated, compared with adipose fat composition, 27.1 ± 4.2% saturated, 49.6 ± 5.7% monounsaturated, and 23.4 ± 3.9% diunsaturated. Proton spectroscopy at 7T offers a simple, fast, noninvasive, and painless method for obtaining detailed information about lipid composition in humans, and the sensitivity and resolution of the method may facilitate longitudinal monitoring of changes in lipid composition in response to diet, exercise, and disease.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
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