Opposed-Phase MRI for Fat Quantification in Fat-Water Phantoms with <sup>1</sup>H MR Spectroscopy to Resolve Ambiguity of Fat or Water Dominance

Chang, Jerry; Taouli, Bachir; Salibi, Nouha; Hecht, Elizabeth M.; Chin, Deanna G.; Lee, Vivian S.

doi:10.2214/ajr.05.0695

Cited by 38 publications

(38 citation statements)

References 15 publications

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“…With MR spectroscopy, on the other hand, data are collected in the absence of a gradient, such that the frequency content of the observed signal reflects the native precessional frequencies of various chemical moieties-water (H 2 O), fat (eg, CH 2 ), and others. In effect, MR spectroscopy directly measures the chemical composition of tissue on the basis of the frequency composition of the signal arising from the voxel of interest (15,16).…”

Section: Mr Spectroscopymentioning

confidence: 99%

Fatty Liver Disease: MR Imaging Techniques for the Detection and Quantification of Liver Steatosis

Cassidy¹,

Yokoo²,

Aganović³

et al. 2009

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Fatty liver disease is the most common cause of chronic liver disease in the United States. Noninvasive detection and quantification of fat is becoming more and more important clinically, due in large part to the growing prevalence of nonalcoholic fatty liver disease. Steatosis, the accumulation of fat-containing vacuoles within hepatocytes, is a key histologic feature of fatty liver disease. Liver biopsy, the current standard of reference for the assessment of steatosis, is invasive, has sampling errors, and is not appropriate in some settings. Several magnetic resonance (MR) imaging-based techniques--including chemical shift imaging, frequency-selective imaging, and MR spectroscopy--are currently in clinical use for the detection and quantification of fat-water admixtures, with each technique having important advantages, disadvantages, and limitations. These techniques permit the breakdown of the net MR signal into fat and water signal components, allowing the quantification of fat in liver tissue, and are increasingly being used in the diagnosis, treatment, and follow-up of fatty liver disease.

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Section: Mr Spectroscopymentioning

confidence: 99%

Fatty Liver Disease: MR Imaging Techniques for the Detection and Quantification of Liver Steatosis

Cassidy¹,

Yokoo²,

Aganović³

et al. 2009

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“…NAFLD is now considered amongst the most concerning liver conditions in children and adults in developed and developing nations (7), and may lead to subsequent development of inflammation and fibrosis in a subset of individuals. With known inherent ambiguity of fat quantification on opposed-phase MRI (8), there is impetus to investigate the continued potential of MRS techniques. Single-voxel 1 H MRS provides localized investigation of water and lipid species in liver, even when lipid amounts are low and difficult to distinguish above noise on MRI.…”

Section: Introductionmentioning

confidence: 99%

“…Recent investigations of hepatic MRS have transcended initial reports documenting its feasibility as a useful examination method of lipid content (1, 9), and evolved into a technique often used as a standard of reference against newly-developed advanced MRI acquisitions (4, 8, 10). Even though these latter studies report significant correlation with MRS, there are several inherent factors affecting the accuracy and reproducibility of lipid% measurements with MRS, such as field homogeneity, partial volume effects, physiologic motion, and signal decay due to relaxation.…”

Section: Introductionmentioning

confidence: 99%

Quantitative analysis of T2‐correction in single‐voxel magnetic resonance spectroscopy of hepatic lipid fraction

Sharma

Martín

Pineda

et al. 2009

Magnetic Resonance Imaging

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Purpose To investigate the accuracy and reproducibility of hepatic lipid measurements using 1H MRS with T2 relaxation correction, in comparison to measurements without correction. Materials and Methods Experiments were conducted in phantoms of varying lipid and iron-induced susceptibility to simulate fatty liver with variable T2. Single-voxel 1H MRS was conducted with multiple TE values, and lipid content (lipid%) was determined at each TE to assess accuracy and TE dependency. Concurrently, T2 and equilibrium values of water and lipid were determined separately, and T2 effects on the lipid% were corrected. A similar procedure was conducted in 12 human subjects to determine susceptibility effects on water and lipid MRS signals and lipid%. Multiple measurements were used to test reproducibility. Results The use of T2-correction was found to be more accurate than uncorrected lipid% in phantom samples (<10% error). Uncorrected lipid% error increased with increasing TE (>20% when TE >24ms) and with increasing susceptibility effect. In humans, while measurement repeatability was high for both corrected and uncorrected MRS, uncorrected lipid% was sensitive to acquisition TE, with 83.6% of all measurements significantly different than T2-corrected measures (p<0.05). Conclusion Separate T2-correction of water and lipid 1H MRS signals provides more accurate and consistent measurements of lipid%, in comparison to uncorrected estimations.

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“…Based on phase differences in images acquired via different TEs, lipid and water signals are additive on in-phase images and subtracted on opposed-phase images [2]. This technique has been proved to be extremely useful for characterization of lesions and organs with fatty components and has gained widespread acceptance [3–6].…”

Section: Introductionmentioning

confidence: 99%

“…In clinical practice, it is widely used to diagnose lipid-poor adrenal adenomas [3, 7]. On the same bias, chemical shift MR imaging has been used to evaluate vertebral bone marrow fat content in osteoporosis or in distinguishing benign and malignant causes of vertebral bone morrow infiltration [2, 4, 7–16]. Furthermore, some investigators measured the signal intensity index (SII) value to avoid the problem of signal intensity variability produced by the reference tissue, and found that it appeared to be the most reliable method for differentiating adenomas from non-adenomas [7, 17].…”

Section: Introductionmentioning

confidence: 99%

Chemical shift MR imaging in the lumbar vertebra: the effect of field strength, scanner vendors and flip angles in repeatability of signal intensity index measurement

Xiao

Li³

et al. 2016

BMC Med Imaging

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BackgroundTo evaluate the reproducibility of signal intensity index (SII) measurements with MRI systems from different vendors and with different field strengths, and to test the effectiveness of flip angle.MethodsThirty-two healthy volunteers (mean age 35.3 ± 9.3 years) were enrolled in this ethics committee-approved study. Chemical shift MR imaging was performed on 1.5- and 3.0-T MR systems from three vendors. Two independent observers measured SII values in five lumbar segments. Inter- and intraobserver agreement was assessed using the interclass correlation coefficients (ICCs). Differences of mean SII values between different field strengths and MR vendors as well as flip angles were compared by using repeated-measures analysis of variance. Differences of mean SII values between different flip angles were also compared by using paired-sample t test.ResultsInter- and intra-observer correlation coefficients showed good agreement (all ICC > 0.75) when measuring SII values at different MR systems (ICCs ranging from 0.896 to 0.983) and flip angles (ICCs ranging from 0.824 to 0.983). There were no significant differences in mean SII values measured by different MR vendors with different field strengths (all p > 0.05 ranging from 0.337 to 0.824). The differences in the mean SII between the four different flip angles were statistically significant (all p < 0.05 ranging from < 0.001 to 0.004) except the group of flip angle 50° versus 70° (p = 0.116).ConclusionThe SII measurement using chemical shift MR imaging may be comparable between different MR systems. Also high flip angles showed better stability to quantitate lumbar fat content.

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Opposed-Phase MRI for Fat Quantification in Fat-Water Phantoms with ¹H MR Spectroscopy to Resolve Ambiguity of Fat or Water Dominance

Cited by 38 publications

References 15 publications

Fatty Liver Disease: MR Imaging Techniques for the Detection and Quantification of Liver Steatosis

Fatty Liver Disease: MR Imaging Techniques for the Detection and Quantification of Liver Steatosis

Quantitative analysis of T2‐correction in single‐voxel magnetic resonance spectroscopy of hepatic lipid fraction

Chemical shift MR imaging in the lumbar vertebra: the effect of field strength, scanner vendors and flip angles in repeatability of signal intensity index measurement

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Opposed-Phase MRI for Fat Quantification in Fat-Water Phantoms with 1H MR Spectroscopy to Resolve Ambiguity of Fat or Water Dominance

Cited by 38 publications

References 15 publications

Fatty Liver Disease: MR Imaging Techniques for the Detection and Quantification of Liver Steatosis

Fatty Liver Disease: MR Imaging Techniques for the Detection and Quantification of Liver Steatosis

Quantitative analysis of T2‐correction in single‐voxel magnetic resonance spectroscopy of hepatic lipid fraction

Chemical shift MR imaging in the lumbar vertebra: the effect of field strength, scanner vendors and flip angles in repeatability of signal intensity index measurement

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Opposed-Phase MRI for Fat Quantification in Fat-Water Phantoms with ¹H MR Spectroscopy to Resolve Ambiguity of Fat or Water Dominance