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Pfleger L, Gajdošík M, Wolf P, Smajis S, Fellinger P, Kuehne A, Krumpolec P, Trattnig S, Winhofer Y, Krebs M, Krššák M, Chmelík M. Absolute Quantification of Phosphor-Containing Metabolites in the Liver Using 31 P MRSI and Hepatic Lipid Volume Correction at 7T Suggests No Dependence on Body Mass Index or Age. J Magn Reson Imaging 2018; 49:597-607. [PMID: 30291654 PMCID: PMC6586048 DOI: 10.1002/jmri.26225] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 05/30/2018] [Accepted: 05/30/2018] [Indexed: 01/07/2023] Open
Abstract
Background Hepatic disorders are often associated with changes in the concentration of phosphorus‐31 (31P) metabolites. Absolute quantification offers a way to assess those metabolites directly but introduces obstacles, especially at higher field strengths (B0 ≥ 7T). Purpose To introduce a feasible method for in vivo absolute quantification of hepatic 31P metabolites and assess its clinical value by probing differences related to volunteers' age and body mass index (BMI). Study Type Prospective cohort. Subjects/Phantoms Four healthy volunteers included in the reproducibility study and 19 healthy subjects arranged into three subgroups according to BMI and age. Phantoms containing 31P solution for correction and validation. Field Strength/Sequence Phase‐encoded 3D pulse‐acquire chemical shift imaging for 31P and single‐volume 1H spectroscopy to assess the hepatocellular lipid content at 7T. Assessment A phantom replacement method was used. Spectra located in the liver with sufficient signal‐to‐noise ratio and no contamination from muscle tissue, were used to calculate following metabolite concentrations: adenosine triphosphates (γ‐ and α‐ATP); glycerophosphocholine (GPC); glycerophosphoethanolamine (GPE); inorganic phosphate (Pi); phosphocholine (PC); phosphoethanolamine (PE); uridine diphosphate‐glucose (UDPG); nicotinamide adenine dinucleotide‐phosphate (NADH); and phosphatidylcholine (PtdC). Correction for hepatic lipid volume fraction (HLVF) was performed. Statistical Tests Differences assessed by analysis of variance with Bonferroni correction for multiple comparison and with a Student's t‐test when appropriate. Results The concentrations for the young lean group corrected for HLVF were 2.56 ± 0.10 mM for γ‐ATP (mean ± standard deviation), α‐ATP: 2.42 ± 0.15 mM, GPC: 3.31 ± 0.27 mM, GPE: 3.38 ± 0.87 mM, Pi: 1.42 ± 0.20 mM, PC: 1.47 ± 0.24 mM, PE: 1.61 ± 0.20 mM, UDPG: 0.74 ± 0.17 mM, NADH: 1.21 ± 0.38 mM, and PtdC: 0.43 ± 0.10 mM. Differences found in ATP levels between lean and overweight volunteers vanished after HLVF correction. Data Conclusion Exploiting the excellent spectral resolution at 7T and using the phantom replacement method, we were able to quantify up to 10 31P‐containing hepatic metabolites. The combination of 31P magnetic resonance spectroscopy imaging data acquisition and HLVF correction was not able to show a possible dependence of 31P metabolite concentrations on BMI or age, in the small healthy population used in this study. Level of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:597–607.
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Affiliation(s)
- Lorenz Pfleger
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Martin Gajdošík
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
- Medical University of Vienna, Department of Biomedical Imaging and Image‐guided Therapy, High Field MR CenterViennaAustria
| | - Peter Wolf
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Sabina Smajis
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Paul Fellinger
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Andre Kuehne
- MRI.TOOLS GmbHBerlinGermany
- Medical University of Vienna, Center for Medical Physics and Biomedical EngineeringViennaAustria
| | - Patrik Krumpolec
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
- Slovak Academy of Sciences, Biomedical Research Center, Institute of Experimental EndocrinologyBratislavaSlovakia
| | - Siegfried Trattnig
- Medical University of Vienna, Department of Biomedical Imaging and Image‐guided Therapy, High Field MR CenterViennaAustria
- Medical University of Vienna, Christian Doppler Laboratory for Clinical Molecular Imaging, MOLIMAViennaAustria
| | - Yvonne Winhofer
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Michael Krebs
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Martin Krššák
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
- Medical University of Vienna, Department of Biomedical Imaging and Image‐guided Therapy, High Field MR CenterViennaAustria
- Medical University of Vienna, Christian Doppler Laboratory for Clinical Molecular Imaging, MOLIMAViennaAustria
| | - Marek Chmelík
- Medical University of Vienna, Department of Biomedical Imaging and Image‐guided Therapy, High Field MR CenterViennaAustria
- Medical University of Vienna, Christian Doppler Laboratory for Clinical Molecular Imaging, MOLIMAViennaAustria
- Karl Landsteiner Institute for Clinical Molecular MRViennaAustria
- University of PrešovFaculty of HealthcarePrešovSlovakia
- General Hospital of Levoča, Radiology DepartmentLevočaSlovakia
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Valkovič L, Chmelík M, Krššák M. In-vivo 31P-MRS of skeletal muscle and liver: A way for non-invasive assessment of their metabolism. Anal Biochem 2017; 529:193-215. [PMID: 28119063 PMCID: PMC5478074 DOI: 10.1016/j.ab.2017.01.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 01/18/2023]
Abstract
In addition to direct assessment of high energy phosphorus containing metabolite content within tissues, phosphorus magnetic resonance spectroscopy (31P-MRS) provides options to measure phospholipid metabolites and cellular pH, as well as the kinetics of chemical reactions of energy metabolism in vivo. Even though the great potential of 31P-MR was recognized over 30 years ago, modern MR systems, as well as new, dedicated hardware and measurement techniques provide further opportunities for research of human biochemistry. This paper presents a methodological overview of the 31P-MR techniques that can be used for basic, physiological, or clinical research of human skeletal muscle and liver in vivo. Practical issues of 31P-MRS experiments and examples of potential applications are also provided. As signal localization is essential for liver 31P-MRS and is important for dynamic muscle examinations as well, typical localization strategies for 31P-MR are also described.
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Affiliation(s)
- Ladislav Valkovič
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Oxford, United Kingdom; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia.
| | - Marek Chmelík
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Institute for Clinical Molecular MRI in Musculoskeletal System, Karl Landsteiner Society, Vienna, Austria
| | - Martin Krššák
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
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Metabolic profile of liver damage in non-cirrhotic virus C and autoimmune hepatitis: A proton decoupled 31P-MRS study. Eur J Radiol 2017; 90:205-211. [PMID: 28583636 DOI: 10.1016/j.ejrad.2017.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/02/2017] [Accepted: 01/08/2017] [Indexed: 12/21/2022]
Abstract
PURPOSE To study liver 31P MRS, histology, transient elastography, and liver function tests in patients with virus C hepatitis (HCV) or autoimmune hepatitis (AIH) to test the hypothesis that 31P MR metabolic profile of these diseases differ. MATERIALS AND METHODS 25 patients with HCV (n=12) or AIH (n=13) underwent proton decoupled 31P MRS spectroscopy performed on a 3.0T MR imager. Intensities of phosphomonoesters (PME) of phosphoethanolamine (PE) and phosphocholine (PC), phosphodiesters (PDE) of glycerophosphoethanolamine (GPE) and glycerophosphocholine (GPC), and γ, α and β resonances of adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH) were determined. Liver stiffness was measured by transient elastography. Inflammation and fibrosis were staged according to METAVIR from biopsy samples. Activities of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALT) and thromboplastin time (TT) were determined from serum samples. RESULTS PME had a stronger correlation with AST (z=1.73, p=0.04) and ALT (z=1.77, p=0.04) in HCV than in AIH patients. PME, PME/PDE, PE/GPE correlated positively and PDE negatively with inflammatory activity. PE, PC and PME correlated positively with liver function tests. CONCLUSION 31P-MRS suggests a more serious liver damage in HCV than in AIH with similar histopathological findings. 31P-MRS is more sensitive in detecting inflammation than fibrosis in the liver.
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Karanjia RN, Crossey MME, Cox IJ, Fye HKS, Njie R, Goldin RD, Taylor-Robinson SD. Hepatic steatosis and fibrosis: Non-invasive assessment. World J Gastroenterol 2016; 22:9880-9897. [PMID: 28018096 PMCID: PMC5143756 DOI: 10.3748/wjg.v22.i45.9880] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/10/2016] [Accepted: 11/16/2016] [Indexed: 02/06/2023] Open
Abstract
Chronic liver disease is a major cause of morbidity and mortality worldwide and usually develops over many years, as a result of chronic inflammation and scarring, resulting in end-stage liver disease and its complications. The progression of disease is characterised by ongoing inflammation and consequent fibrosis, although hepatic steatosis is increasingly being recognised as an important pathological feature of disease, rather than being simply an innocent bystander. However, the current gold standard method of quantifying and staging liver disease, histological analysis by liver biopsy, has several limitations and can have associated morbidity and even mortality. Therefore, there is a clear need for safe and non-invasive assessment modalities to determine hepatic steatosis, inflammation and fibrosis. This review covers key mechanisms and the importance of fibrosis and steatosis in the progression of liver disease. We address non-invasive imaging and blood biomarker assessments that can be used as an alternative to information gained on liver biopsy.
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Abstract
The diagnostics of diffuse liver disease traditionally rely on liver biopsies and histopathological analysis of tissue specimens. However, a liver biopsy is invasive and carries some non-negligible risks, especially for patients with decreased liver function and those requiring repeated follow-up examinations. Over the last decades, magnetic resonance imaging (MRI) has developed into a valuable tool for the non-invasive characterization of focal liver lesions and diseases of the bile ducts. Recently, several MRI methods have been developed and clinically evaluated that also allow the diagnostics and staging of diffuse liver diseases, e.g. non-alcoholic fatty liver disease, hepatitis, hepatic fibrosis, liver cirrhosis, hemochromatosis and hemosiderosis. The sequelae of diffuse liver diseases, such as a decreased liver functional reserve or portal hypertension, can also be detected and quantified by modern MRI methods. This article provides the reader with the basic principles of functional MRI of the liver and discusses the importance in a clinical context.
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Chmelik M, Považan M, Krššák M, Gruber S, Tkačov M, Trattnig S, Bogner W. In vivo (31)P magnetic resonance spectroscopy of the human liver at 7 T: an initial experience. NMR IN BIOMEDICINE 2014; 27:478-85. [PMID: 24615903 DOI: 10.1002/nbm.3084] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 12/11/2013] [Accepted: 01/07/2014] [Indexed: 05/12/2023]
Abstract
Phosphorus ((31) P) MRS is a powerful tool for the non-invasive investigation of human liver metabolism. Four in vivo (31) P localization approaches (single voxel image selected in vivo spectroscopy (3D-ISIS), slab selective 1D-ISIS, 2D chemical shift imaging (CSI), and 3D-CSI) with different voxel volumes and acquisition times were demonstrated in nine healthy volunteers. Localization techniques provided comparable signal-to-noise ratios normalized for voxel volume and acquisition time differences, Cramer-Rao lower bounds (8.7 ± 3.3%1D-ISIS , 7.6 ± 2.5%3D-ISIS , 8.6 ± 4.2%2D-CSI , 10.3 ± 2.7%3D-CSI ), and linewidths (50 ± 24 Hz1D-ISIS , 34 ± 10 Hz3D-ISIS , 33 ± 10 Hz2D-CSI , 34 ± 11 Hz3D-CSI ). Longitudinal (T1 ) relaxation times of human liver metabolites at 7 T were assessed by 1D-ISIS inversion recovery in the same volunteers (n = 9). T1 relaxation times of hepatic (31) P metabolites at 7 T were the following: phosphorylethanolamine - 4.41 ± 1.55 s; phosphorylcholine - 3.74 ± 1.31 s; inorganic phosphate - 0.70 ± 0.33 s; glycerol 3-phosphorylethanolamine - 6.19 ± 0.91 s; glycerol 3-phosphorylcholine - 5.94 ± 0.73 s; γ-adenosine triphosphate (ATP) - 0.50 ± 0.08 s; α-ATP - 0.46 ± 0.07 s; β-ATP - 0.56 ± 0.07 s. The improved spectral resolution at 7 T enabled separation of resonances in the phosphomonoester and phosphodiester spectral region as well as nicotinamide adenine dinucleotide and uridine diphosphoglucose signals. An additional resonance at 2.06 ppm previously assigned to phosphoenolpyruvate or phosphatidylcholine is also detectable. These are the first (31) P metabolite relaxation time measurements at 7 T in human liver, and they will help in the exploration of new, exciting questions in metabolic research with 7 T MR.
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Affiliation(s)
- Marek Chmelik
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
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Zhang CY, Zhang Q, Zhang HM, Yang HS. 3.0T 31P MR spectroscopy in assessment of response to antiviral therapy for chronic hepatitis C. World J Gastroenterol 2014; 20:2107-2112. [PMID: 24587683 PMCID: PMC3934482 DOI: 10.3748/wjg.v20.i8.2107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Accepted: 01/05/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the utility of phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) as a noninvasive test for assessment of response to interferon and ribavirin treatment in patients with different severities of hepatitis C virus infection.
METHODS: Sixty chronic hepatitis C patients undergoing antiviral therapy with interferon and ribavirin underwent 31P MRS at 3.0T before treatment, 6 mo after the start of treatment, and 1 year after the start of treatment.
RESULTS: The phosphomonoester (PME)/phosphodiester (PDE) ratio at 6 mo after the start of antiviral therapy in the Child-Pugh B and C groups were significantly higher than those before therapy, but this was not seen in the Child-Pugh A group. In the antiviral therapy group, the PME/PDE ratios had decreased on follow-up MR spectroscopy. However, in the virological nonresponder group, the PME/PDE ratios on follow-up imaging were similar to the baseline values.
CONCLUSION: 31P MRS can be used to provide biochemical information on hepatic metabolic processes. This study indicates that the PME/PDE ratio can be used as an indicator of response to antiviral treatment in chronic hepatitis C patients.
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Lim AKP, Patel N, Eckersley RJ, Fitzpatrick J, Crossey MME, Hamilton G, Goldin RD, Thomas HC, Vennart W, Cosgrove DO, Taylor-Robinson SD. A comparison of 31P magnetic resonance spectroscopy and microbubble-enhanced ultrasound for characterizing hepatitis c-related liver disease. J Viral Hepat 2011; 18:e530-4. [PMID: 21914073 DOI: 10.1111/j.1365-2893.2011.01455.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We compared in vivo hepatic (31) P magnetic resonance spectroscopy ((31) P MRS) and hepatic vein transit times (HVTT) using contrast-enhanced ultrasound with a microbubble agent to assess the severity of hepatitis C virus (HCV)-related liver disease. Forty-six patients with biopsy-proven HCV-related liver disease and nine healthy volunteers had (31) P MRS and HVTT performed on the same day. (31) P MR spectra were obtained at 1.5 T. Peak areas were calculated for metabolites, including phosphomonoesters (PME) and phosphodiesters (PDE). Patients also had the microbubble ultrasound contrast agent, Levovist (2 g), injected into an antecubital vein, and time-intensity Doppler ultrasound signals of the right and middle hepatic veins were measured. The HVTT was calculated as the time from injection to a sustained rise in Doppler signal 10% greater than baseline. The shortest times were used for analysis. Based on Ishak histological scoring, there were 15 patients with mild hepatitis, 20 with moderate/severe hepatitis and 11 with cirrhosis. With increasing severity of disease, the PME/PDE ratio was steadily elevated, while the HVTT showed a monotonic decrease. Both imaging modalities could separate patients with cirrhosis from the mild and moderate/severe hepatitis groups. No statistical difference was observed in the accuracy of each test to denote mild, moderate/severe hepatitis and cirrhosis (Fisher's exact test P =1.00). (31) P MRS and HVTT show much promise as noninvasive imaging tests for assessing the severity of chronic liver disease. Both are equally effective and highly sensitive in detecting cirrhosis.
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Affiliation(s)
- A K P Lim
- Imaging Sciences Department, Institute of Clinical Sciences Centre, Faculty of Medicine, London, UK.
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Wylezinska M, Cobbold JFL, Fitzpatrick J, McPhail MJW, Crossey MME, Thomas HC, Hajnal JV, Vennart W, Cox IJ, Taylor-Robinson SD. A comparison of single-voxel clinical in vivo hepatic 31P MR spectra acquired at 1.5 and 3.0 Tesla in health and diseased states. NMR IN BIOMEDICINE 2011; 24:231-237. [PMID: 20949641 DOI: 10.1002/nbm.1578] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2009] [Revised: 05/15/2010] [Accepted: 05/17/2010] [Indexed: 05/30/2023]
Abstract
With the increasing availability of human MR scanners at various field strengths, the optimal field strength for in vivo clinical MR studies of the liver has become a focus of attention. Comparison between results at 3.0 and 1.5 T is of particular clinical interest, especially for multicentre studies. For MRS studies, higher field strengths should be advantageous, because improved sensitivity and chemical shift dispersion are expected. We report a comparison between single-voxel hepatic proton-decoupled (31)P MRS performed at 1.5 and 3.0 T in the same subjects using similar methodologies. Twelve healthy volunteers and 15 patients with chronic liver disease were studied. Improved spectral resolution was achieved using proton decoupling, and there was an improvement (21%) in the signal-to-noise ratio (SNR) of the phosphomonoester (PME) resonance at 3.0 T relative to 1.5 T. There was no significant change in nuclear Overhauser effects for PME or phosphodiesters (PDEs) between the two field strengths. The T(1) value of PDE was significantly longer at 3 T, although there was no significant change in the T(1) value of PME. There was no significant difference in the mean PME/PDE ratios for either the control or patient groups at both 1.5 and 3.0 T, but there was a small positive mean difference in PME/PDE at 3.0 T on pairwise testing between field strengths (+ 0.05, p < 0.01). There were significant correlations between PME/PDE values at the two magnetic field strengths (r = 0.806, p < 0.001). The underlying broad resonance was reduced at 3.0 T relative to 1.5 T, related to line broadening of the phospholipid bilayer signal. In conclusion, there was an improvement in hepatic (31)P MR signal quality at 3.0 T relative to 1.5 T. Broadly similar hepatic (31)P MR parameters were obtained at 1.5 and 3.0 T. The modest difference noted in the PME/PDE ratio between field strengths for patients with chronic liver disease should inform multicentre study design involving these field strengths.
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Affiliation(s)
- Marzena Wylezinska
- Hepatology and Gastroenterology Section, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, St Mary's Campus, Faculty of Medicine, Imperial College London, London, UK
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Lim AKP, Patel N, Eckersley RJ, Cobbold JFL, Crossey MME, Cosgrove DO, Goldin RD, Thomas HC, Taylor-Robinson SD. Hepatic vein transit times of a microbubble agent in assessing response to antiviral treatment in patients with chronic hepatitis C. J Viral Hepat 2010; 17:778-83. [PMID: 20002308 DOI: 10.1111/j.1365-2893.2009.01234.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Microbubble measurement of hepatic vein transit times (HVTT) may have the potential to assess severity of hepatitis C virus (HCV)-related liver disease, where there is a shorter HVTT with more severe disease. We investigated the utility of this test as a marker of response to antiviral treatment. Thirty-seven patients with biopsy-proven HCV-related disease undergoing antiviral treatment were studied. All had baseline scans and then repeat scans 6 months after the end of treatment. HVTT using Levovist were obtained from the right and middle hepatic veins, and the shorter time was used for analysis. The aspartate aminotransferase to platelet ratio index (APRI) scores were calculated retrospectively. There were seven patients with mild hepatitis, 23 with moderate/severe hepatitis and seven with cirrhosis. The mean baseline HVTT in responders ± SE increased from 27.3 ± 2.29 s to 33.5 ± 2.8 s posttreatment (P = 0.01). In the 10 nonresponders, the HVTT remained the same; 43.3 ± 9 s baseline compared to 44 ± 7.8 s posttreatment (P = 0.84). This trend was also seen with the APRI score where in responders, the mean score decreased from 1.1 ± 0.2 to 0.74 ± 1 (P = 0.03) and in nonresponders, the score remained unchanged; 0.88 ± 0.2 compared to 0.84 ± 0.2 (P = 0.31). HVTT measurement lengthened, while APRI scores decreased in patients who responded to antiviral treatment while both remained the same, shortened (HVTT) or increased (APRI), respectively, in patients who were nonresponders. These results are encouraging and indicate that these tests could be potentially used as markers of response to treatment and could obviate the need for serial biopsies in antiviral future treatment studies.
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Affiliation(s)
- A K P Lim
- Clinical Sciences Centre, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.
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Dagnelie PC, Leij-Halfwerk S. Magnetic resonance spectroscopy to study hepatic metabolism in diffuse liver diseases, diabetes and cancer. World J Gastroenterol 2010; 16:1577-86. [PMID: 20355236 PMCID: PMC2848366 DOI: 10.3748/wjg.v16.i13.1577] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
This review provides an overview of the current state of the art of magnetic resonance spectroscopy (MRS) in in vivo investigations of diffuse liver disease. So far, MRS of the human liver in vivo has mainly been used as a research tool rather than a clinical tool. The liver is particularly suitable for static and dynamic metabolic studies due to its high metabolic activity. Furthermore, its relatively superficial position allows excellent MRS localization, while its large volume allows detection of signals with relatively low intensity. This review describes the application of MRS to study the metabolic consequences of different conditions including diffuse and chronic liver diseases, congenital diseases, diabetes, and the presence of a distant malignancy on hepatic metabolism. In addition, future prospects of MRS are discussed. It is anticipated that future technical developments such as clinical MRS magnets with higher field strength (3 T) and improved delineation of multi-component signals such as phosphomonoester and phosphodiester using proton decoupling, especially if combined with price reductions for stable isotope tracers, will lead to intensified research into metabolic syndrome, cardiovascular disease, hepato-biliary diseases, as well as non-metastatic liver metabolism in patients with a distant malignant tumor.
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Abstract
Magnetic resonance (MR) spectroscopy allows the demonstration of relative tissue metabolite concentrations along a two- or three-dimensional spectrum based on the chemical shift phenomenon. An MR spectrum is a plot of the signal intensity and frequency of a chemical or metabolite within a given voxel. At proton MR spectroscopy, the frequency at which a chemical or compound occurs depends on the configuration of the protons within the structure of that chemical. At in vivo proton MR spectroscopy, the frequency location of water is used as the standard of reference to identify a chemical. The frequency shift or location of chemicals relative to that of water allows generation of qualitative and quantitative information about the chemicals that occur within tissues, forming the basis of tissue characterization by MR spectroscopy. MR spectroscopy also may be used to quantify liver fat by measuring lipid peaks and to diagnose malignancy, usually by measuring the choline peak. Interpretation of MR spectroscopic data requires specialized postprocessing software and is subject to technical limitations including low signal-to-noise ratio, masking of metabolite peaks by dominant water and lipid peaks, partial-volume averaging from other tissue within the voxel, and phase and frequency shifts from motion. MR spectroscopy of the liver is an evolving technology with potential for improving the diagnostic accuracy of tissue characterization when spectra are interpreted in conjunction with MR images.
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Affiliation(s)
- Aliya Qayyum
- Department of Radiology, University of California San Francisco, Box 0628, L-307, 505 Parnassus Ave, San Francisco, CA 94143-0628, USA.
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Sijens PE. Parametric exploration of the liver by magnetic resonance methods. Eur Radiol 2009; 19:2594-607. [PMID: 19504103 PMCID: PMC2762052 DOI: 10.1007/s00330-009-1470-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 04/24/2009] [Accepted: 04/30/2009] [Indexed: 12/16/2022]
Abstract
MRI, as a completely noninvasive technique, can provide quantitative assessment of perfusion, diffusion, viscoelasticity and metabolism, yielding diverse information about liver function. Furthermore, pathological accumulations of iron and lipids can be quantified. Perfusion MRI with various contrast agents is commonly used for the detection and characterization of focal liver disease and the quantification of blood flow parameters. An extended new application is the evaluation of the therapeutic effect of antiangiogenic drugs on liver tumours. Novel, but already widespread, is a histologically validated relaxometry method using five gradient echo sequences for quantifying liver iron content elevation, a measure of inflammation, liver disease and cancer. Because of the high perfusion fraction in the liver, the apparent diffusion coefficients strongly depend on the gradient factors used in diffusion-weighted MRI. While complicating analysis, this offers the opportunity to study perfusion without contrast injection. Another novel method, MR elastography, has already been established as the only technique able to stage fibrosis or diagnose mild disease. Liver fat content is accurately determined with multivoxel MR spectroscopy (MRS) or by faster MRI methods that are, despite their widespread use, prone to systematic error. Focal liver disease characterisation will be of great benefit once multivoxel methods with fat suppression are implemented in proton MRS, in particular on high-field MR systems providing gains in signal-to-noise ratio and spectral resolution.
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Affiliation(s)
- Paul E Sijens
- Radiology, University Medical Center Groningen and University of Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.
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