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Biopsy-based optimization and calibration of a signal-intensity-ratio-based MRI method (1.5 Tesla) in a dextran-iron loaded mini-pig model, enabling estimation of very high liver iron concentrations. MAGNETIC RESONANCE MATERIALS IN PHYSICS, BIOLOGY AND MEDICINE 2022; 35:843-859. [PMID: 35038062 PMCID: PMC9463247 DOI: 10.1007/s10334-021-00998-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 12/26/2021] [Accepted: 12/28/2021] [Indexed: 11/15/2022]
Abstract
Objective Magnetic resonance imaging (MRI)-based techniques for non-invasive assessing liver iron concentration (LIC) in patients with iron overload have a limited upper measuring range around 35 mg/g dry weight, caused by signal loss from accelerated T1-, T2-, T2* shortening with increasing LIC. Expansion of this range is necessary to allow evaluation of patients with very high LIC. Aim To assess measuring range of a gradient-echo R2* method and a T1-weighted spin-echo (SE), signal intensity ratio (SIR)-based method (TE = 25 ms, TR = 560 ms), and to extend the upper measuring range of the SIR method by optimizing echo time (TE) and repetition time (TR) in iron-loaded minipigs. Methods Thirteen mini pigs were followed up during dextran-iron loading with repeated percutaneous liver biopsies for chemical LIC measurement and MRIs for parallel non-invasive estimation of LIC (81 examinations) using different TEs and TRs. Results SIR and R2* method had similar upper measuring range around 34 mg/g and similar method agreement. Using TE = 12 ms and TR = 1200 ms extended the upper measuring range to 115 mg/g and yielded good method of agreement. Discussion The wider measuring range is likely caused by lesser sensitivity of the SE sequence to iron, due to shorter TE, leading to later signal loss at high LIC, allowing evaluation of most severe hepatic iron overload. Validation in iron-loaded patients is necessary.
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Tunnicliffe EM, Banerjee R, Pavlides M, Neubauer S, Robson MD. A model for hepatic fibrosis: the competing effects of cell loss and iron on shortened modified Look-Locker inversion recovery T 1 (shMOLLI-T 1 ) in the liver. J Magn Reson Imaging 2016; 45:450-462. [PMID: 27448630 DOI: 10.1002/jmri.25392] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 07/05/2016] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To propose a simple multicompartment model of the liver and use Bloch-McConnell simulations to demonstrate the effects of iron and fibrosis on shortened-MOLLI (shMOLLI) T1 measurements. Liver T1 values have shown sensitivity to inflammation and fibrosis, but are also affected by hepatic iron content. Modified Look-Locker inversion recovery (MOLLI) T1 measurements are biased by the lower T2 associated with high iron. MATERIALS AND METHODS A tissue model was generated consisting of liver cells and extracellular fluid (ECF), with iron-dependent relaxation rates. Fibrosis was imitated by increasing the ECF proportion. Simulations of the shMOLLI sequence produced a look-up table (LUT) of shMOLLI-T1 for a given ECF fraction and iron content. The LUT was used to calculate ECF(shMOLLI-T1 ), assuming normal hepatic iron content (HIC), and ECF(shMOLLI- T1,T2*), accounting for HIC determined by T2*, for 77 patients and compared to fibrosis assessed by liver biopsy. RESULTS Simulations showed that increasing HIC decreases shMOLLI-T1 , with an increase in HIC from 1.0 to 2.5 mg/g at normal ECF fraction decreasing shMOLLI-T1 by 160 msec, while increasing ECF increased ShMOLLI-T1 , with an increase of 20% ECF at normal iron increasing shMOLLI-T1 by 200 msec. Calculated patient ECF(shMOLLI-T1 ) showed a strong dependence on Ishak score (3.3 ± 0.8 %ECF/Ishak stage) and 1/T2* (-0.23 ± 0.04 %ECF/Hz). However, when iron was accounted for to produce ECF(shMOLLI- T1,T2*), it was independent of HIC but retained sensitivity to Ishak score. CONCLUSION Use of this multicompartment model of the liver with Bloch-McConnell simulation should enable compensation of iron effects when using shMOLLI-T1 to assess fibrosis. LEVEL OF EVIDENCE 1 J. Magn. Reson. Imaging 2017;45:450-462.
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Affiliation(s)
- Elizabeth M Tunnicliffe
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Rajarshi Banerjee
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Michael Pavlides
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK.,Translational Gastroenterology Unit, University of Oxford, Oxford, UK
| | - Stefan Neubauer
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Matthew D Robson
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
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Chin JL, Pavlides M, Moolla A, Ryan JD. Non-invasive Markers of Liver Fibrosis: Adjuncts or Alternatives to Liver Biopsy? Front Pharmacol 2016; 7:159. [PMID: 27378924 PMCID: PMC4913110 DOI: 10.3389/fphar.2016.00159] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 05/31/2016] [Indexed: 12/13/2022] Open
Abstract
Liver fibrosis reflects sustained liver injury often from multiple, simultaneous factors. Whilst the presence of mild fibrosis on biopsy can be a reassuring finding, the identification of advanced fibrosis is critical to the management of patients with chronic liver disease. This necessity has lead to a reliance on liver biopsy which itself is an imperfect test and poorly accepted by patients. The development of robust tools to non-invasively assess liver fibrosis has dramatically enhanced clinical decision making in patients with chronic liver disease, allowing a rapid and informed judgment of disease stage and prognosis. Should a liver biopsy be required, the appropriateness is clearer and the diagnostic yield is greater with the use of these adjuncts. While a number of non-invasive liver fibrosis markers are now used in routine practice, a steady stream of innovative approaches exists. With improvement in the reliability, reproducibility and feasibility of these markers, their potential role in disease management is increasing. Moreover, their adoption into clinical trials as outcome measures reflects their validity and dynamic nature. This review will summarize and appraise the current and novel non-invasive markers of liver fibrosis, both blood and imaging based, and look at their prospective application in everyday clinical care.
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Affiliation(s)
- Jun L Chin
- School of Medicine and Medical Science, University College Dublin Dublin, Ireland
| | - Michael Pavlides
- Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford Oxford, UK
| | - Ahmad Moolla
- Radcliffe Department of Medicine, University of Oxford Oxford, UK
| | - John D Ryan
- Translational Gastroenterology Unit, University of Oxford Oxford, UK
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MR relaxometry of the liver: significant elevation of T1 relaxation time in patients with liver cirrhosis. Eur Radiol 2012; 22:1224-32. [DOI: 10.1007/s00330-012-2378-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 12/06/2011] [Accepted: 12/15/2011] [Indexed: 12/13/2022]
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Guiu B, Loffroy R, Hillon P, Petit JM. Magnetic resonance imaging and spectroscopy for quantification of hepatic steatosis: urgent need for standardization! J Hepatol 2009; 51:1082-3; author reply 1083-4. [PMID: 19815306 DOI: 10.1016/j.jhep.2009.09.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Bonekamp S, Kamel I, Solga S, Clark J. Can imaging modalities diagnose and stage hepatic fibrosis and cirrhosis accurately? J Hepatol 2009; 50:17-35. [PMID: 19022517 DOI: 10.1016/j.jhep.2008.10.016] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The accurate diagnosis and staging of hepatic fibrosis is crucial for prognosis and treatment of liver disease. The current gold standard, liver biopsy, cannot be used for population-based screening, and has well known drawbacks if used for monitoring of disease progression or treatment success. Our objective was to assess performance and promise of radiologic modalities and techniques as alternative, noninvasive assessment of hepatic fibrosis. A systematic review was conducted. Six hundred twenty-eight studies were identified via electronic search. One hundred fifty-three papers were reviewed. Most described techniques that could differentiate between cirrhosis or severe fibrosis and normal liver. Accurate staging of fibrosis or diagnosis of mild fibrosis was often not achievable. Ultrasonography is the most common modality used in the diagnosis and staging of hepatic fibrosis. Elastographic measurements, either ultrasonography-based or magnetic resonance-based, and magnetic resonance diffusion weighted imaging, show the most promise for accurate staging of hepatic fibrosis. Most currently available imaging techniques can detect cirrhosis or significant fibrosis reasonably accurately. However, to date only magnetic resonance elastography has been able to stage fibrosis or diagnose mild disease. Utrasonographic elastography and magnetic resonance diffusion weighted appear next most promising.
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Affiliation(s)
- Susanne Bonekamp
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Aubé C, Moal F, Oberti F, Roux J, Croquet V, Gallois Y, Argaud C, Caron C, Calès P. Diagnosis and measurement of liver fibrosis by MRI in bile duct ligated rats. Dig Dis Sci 2007; 52:2601-9. [PMID: 17429735 DOI: 10.1007/s10620-006-9143-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Accepted: 11/10/2005] [Indexed: 01/06/2023]
Abstract
The noninvasive evaluation of liver fibrosis is a major clinical goal in liver diseases. Our aim was to identify MRI parameters to quantify liver fibrosis in vivo in an animal model of liver fibrosis with slight inflammation. We evaluated serum hyaluronate, liver hydroxyproline, area of liver fibrosis (image analysis), and 1.5-T MRI in 10 sham rats and 24 bile duct ligated rats with different stages of liver fibrosis. Liver signal intensity (SI)/muscle SI ratio and liver relaxation times (rT) were measured on T1 and T2 weighted sequences at different echo (TE) or recovery (RT) times of MRI. Among the 66 MRI parameters tested, the highest correlation with the area of fibrosis was observed for rT2 (r=0.78, P < 0.01). The area of liver fibrosis was independently predicted by five MRI variables (adjusted R (2)=0.78, with R (2)=0.64 for rT2 and rT1). Diagnostic accuracy for liver fibrosis was 100% using two variables: liver/muscle SI ratio on T2 at 30-ms TE and liver/muscle SI ratio on T1 at 50-ms RT. We conclude that in this animal model, fibrosis could be diagnosed with an accuracy of 100% using two MRI parameters. The quantification of liver fibrosis was very accurate either with only one MRI parameter (r=0.78 for rT2) or with five parameters (r=0.90) in this cholestatic model.
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Affiliation(s)
- Christophe Aubé
- Department of Radiology, University Hospital, Angers, France.
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Fritz GA, Schoellnast H, Deutschmann HA, Wiltgen M, Brader P, Berghold A, Groell R. Density histogram analysis of unenhanced hepatic computed tomography in patients with diffuse liver diseases. J Comput Assist Tomogr 2006; 30:201-5. [PMID: 16628032 DOI: 10.1097/00004728-200603000-00006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE The aim of the study was to assess the potential of density histogram analysis of unenhanced hepatic computed tomography (CT) in the diagnosis and differentiation of diffuse liver diseases. METHODS Twenty-six patients with normal liver parenchyma, 35 patients with diffuse steatosis, 14 patients with acute steatohepatitis, 15 patients with active alcoholic cirrhosis, 23 patients with inactive alcoholic cirrhosis, 15 patients with virus-induced cirrhosis, and 8 patients with hemochromatosis underwent unenhanced hepatic CT. All diffuse liver diseases and the absence of diffuse liver disease were histologically proven. Quantitative analysis of unenhanced liver parenchyma was performed in each patient. RESULTS The hepatic density histogram showed no significant differences in kurtosis and skewness between the groups (P > 0.05). Except for steatosis, active alcoholic cirrhosis, and hemochromatosis, diffuse liver diseases led to similar densities of liver parenchyma in unenhanced hepatic CT. CONCLUSION A reliable diagnosis and differentiation of diffuse liver diseases on the basis of density histogram analysis is not possible.
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Affiliation(s)
- Gerald A Fritz
- Department of Radiology, University Hospital Graz, Graz, Austria.
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Bokacheva L, Huang AJ, Chen Q, Oesingmann N, Storey P, Rusinek H, Lee VS. Single breath-holdT1 measurement using low flip angle TrueFISP. Magn Reson Med 2006; 55:1186-90. [PMID: 16572392 DOI: 10.1002/mrm.20845] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A method for estimating T1 using a single breath-hold, segmented, inversion recovery prepared, true fast imaging with steady-state precession (sIR-TrueFISP) acquisition at low flip angle (FA) was implemented in this study. T1 values measured by sIR-TrueFISP technique in a Gd-DTPA-doped water phantom and the human brain and abdomen of healthy volunteers were compared with the results of the standard IR fast spin echo (FSE) technique. A good correlation between the two methods was observed (R2=0.999 in the phantom, and R2=0.943 in the brain and abdominal tissues). The T1 values of the tissues agreed well with published results. sIR-TrueFISP enables fast measurements of T1 to be obtained within a single breath-hold with good accuracy, which is particularly important for chest and abdominal imaging.
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Affiliation(s)
- L Bokacheva
- Department of Radiology, New York University School of Medicine, New York, New York 10016, USA
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Abstract
MR imaging is establishing a role as a primary diagnostic technique, with increasing evidence showing MR imaging to have advantages over CT regarding diagnostic sensitivity and specificity for many pathologies of solid organs, bile and pancreatic ducts, bowel, peritoneum, and retroperitoneum. In addition, there are increasing concerns regarding the risks of radiation and iodinated contrast associated with CT imaging of the abdomen. The incidence of contrast-induced nephropathy associated with iodinated contrast used for CT scanning is difficult to ascertain because reporting is spurious and variable in interpretation.
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Affiliation(s)
- Diego R Martin
- Department of Radiology, Emory University School of Medicine, 1364 Clifton Road NE, Atlanta, GA 30322, USA.
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Abstract
This article discusses MR imaging sequences that are used for the evaluation of diffuse liver diseases, including processes that lead to abnormal lipid metabolization, iron de-position disease, and perfusion abnormalities.
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Affiliation(s)
- Raman Danrad
- Department of Radiology, Emory University School of Medicine, 1365 Clifton Road NE, Atlanta, GA 30322, USA
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Martin DR, Semelka RC. Magnetic Resonance Imaging of the Liver: Review of Techniques and Approach to Common Diseases. Semin Ultrasound CT MR 2005; 26:116-31. [PMID: 15987062 DOI: 10.1053/j.sult.2005.02.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
MR imaging examination of the liver should use a combination of single-shot T2W and breath-hold T1W images, and include gadolinium enhancement with acquisition of multiple phases. MR provides superior characterization of liver masses than CT, and multi-phase gadolinium enhancement including a properly timed arterial phase is critical. The T1 weighted pre-contrast images must include in-phase/out-of-phase acquisitions, to assess hepatic lipid and or iron content, and dynamically enhanced post-gadolinium images. Timing of the arterial phase images is also critical for demonstration of acute hepatitis. The timing of the venous and equilibrium phase images are less critical, and are important for grading more severe acute hepatitis, demonstration of fibrosis, and for delineating vascular abnormalities. In cirrhosis, dynamic post-gadolinium images are critical for detection and characterization of regenerative or dysplastic nodules, and HCC. The same sequences useful for liver evaluation provide a comprehensive evaluation of all the soft tissues of the abdomen, and allow depiction of most of the important diseases, thus facilitating use of a universal protocol for abdominal imaging.
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Affiliation(s)
- Diego R Martin
- Department of Radiology, Emory University Hospital, Atlanta, GA 30322, USA.
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Abstract
The intrinsic soft tissue contrast and exquisite sensitivity to contrast agents are unique attributes of magnetic resonance imaging that are beneficial when evaluating diffuse liver disease. Much like a pathologist uses different tissue or cell marker stains, the magnetic resonance imager can use a variety of imaging strategies to elucidate pathologic liver processes in vivo, including processes leading to abnormal lipid metabolization, iron deposition, perfusion abnormalities related to inflammation, fibrosis, vascular occlusion, or infarction and hemorrhage. This article reviews the most important diffuse liver diseases and the corresponding magnetic resonance imaging features.
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Affiliation(s)
- Diego R Martin
- Department of Radiology, Robert C Byrd Health Sciences Center, West Virginia University, West Virginia 26506-9235, USA.
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Macdonald GA, Peduto AJ. Magnetic resonance imaging (MRI) and diseases of the liver and biliary tract. Part 1. Basic principles, MRI in the assessment of diffuse and focal hepatic disease. J Gastroenterol Hepatol 2000; 15:980-91. [PMID: 11059926 DOI: 10.1046/j.1440-1746.2000.02278.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Magnetic resonance imaging (MRI) relies on the physical properties of unpaired protons in tissues to generate images. Unpaired protons behave like tiny bar magnets and will align themselves in a magnetic field. Radiofrequency pulses will excite these aligned protons to higher energy states. As they return to their original state, they will release this energy as radio waves. The frequency of the radio waves depends on the local magnetic field and by varying this over a subject, it is possible to build the images we are familiar with. In general, MRI has not been sufficiently sensitive or specific in the assessment of diffuse liver disease for clinical use. However, because of the specific characteristics of fat and iron, it may be useful in the assessment of hepatic steatosis and iron overload. Magnetic resonance imaging is useful in the assessment of focal liver disease, particularly in conjunction with contrast agents. Haemangiomas have a characteristic bright appearance on T2 weighted images because of the slow flowing blood in dilated sinusoids. Focal nodular hyperplasia (FNH) has a homogenous appearance, and enhances early in the arterial phase after gadolinium injection, while the central scar typically enhances late. Hepatic adenomas have a more heterogenous appearance and also enhance in the arterial phase, but less briskly than FNH. Hepatocellular carcinoma is similar to an adenoma, but typically occurs in a cirrhotic liver and has earlier washout of contrast. The appearance of metastases depends on the underlying primary malignancy. Overall, MRI appears more sensitive and specific than computed tomography with contrast for the detection and evaluation of malignant lesions.
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Affiliation(s)
- G A Macdonald
- The Department of Medicine, The University of Queensland and The Queensland Institute of Medical Research, Brisbane, Australia.
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