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1.  In vivo characterization of the liver fat 1H MR spectrum 
NMR in biomedicine  2010;24(7):10.1002/nbm.1622.
A theoretical triglyceride model was developed for in vivo human liver fat 1H MRS characterization, using the number of double bonds (–CH=CH–), number of methylene-interrupted double bonds (–CH=CH–CH2–CH=CH–) and average fatty acid chain length. Five 3 T, single-voxel, stimulated echo acquisition mode spectra (STEAM) were acquired consecutively at progressively longer TEs in a fat–water emulsion phantom and in 121 human subjects with known or suspected nonalcoholic fatty liver disease. T2-corrected peak areas were calculated. Phantom data were used to validate the model. Human data were used in the model to determine the complete liver fat spectrum. In the fat–water emulsion phantom, the spectrum predicted by the model (based on known fatty acid chain distribution) agreed closely with spectroscopic measurement. In human subjects, areas of CH2 peaks at 2.1 and 1.3 ppm were linearly correlated (slope, 0.172; r = 0.991), as were the 0.9 ppm CH3 and 1.3 ppm CH2 peaks (slope, 0.125; r = 0.989). The 2.75 ppm CH2 peak represented 0.6% of the total fat signal in high-liver-fat subjects. These values predict that 8.6% ofm the total fat signal overlies the water peak. The triglyceride model can characterize human liver fat spectra. This allows more accurate determination of liver fat fraction from MRI and MRS.
PMCID: PMC3860876  PMID: 21834002
liver; 1H MRS; triglyceride; quantification; NAFLD; fat fraction
2.  Phase I study of miriplatin combined with transarterial chemotherapy using CDDP powder in patients with hepatocellular carcinoma 
BMC Gastroenterology  2012;12:127.
There is no standard therapeutic procedure for the hepatocellular carcinoma (HCC) in patients with poor hepatic reserve function. With the approval of newly developed chemotherapeutic agent of miriplatin, we have firstly conducted the phase I study of CDDP powder (DDP-H) and miriplatin combination therapy and reported its safety and efficacy for treating unresectable HCC in such cases. To determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) for the combination of transarterial oily chemoembolization (TOCE) and transarterial chemotherapy (TAC) using miriplatin and DDP-H for treating unresectable hepatocellular carcinoma (HCC).
Transarterial chemotherapy using DDP-H was performed through the proper hepatic artery targeting the HCC nodules by increasing the dose of DDP-H (35–65 mg/m2) followed by targeting the HCC nodules by transarterial oily chemoembolization with miriplatin.
A total of nine patients were enrolled in this study and no DLT was observed with any dose of DDP-H in all cases in whom 80 mg (median, 18–120) miriplatin was administered. An anti-tumour efficacy rating for partial response was obtained in one patient, while a total of four patients (among eight evaluated) showed stable disease response, leading to 62.5% of disease control rate. The pharmacokinetic results showed no further increase in plasma platinum concentration following miriplatin administration.
Our results suggest that a combination of DDP-H and miriplatin can be safely administered up to their respective MTD for treating HCC.
Trial registration
This study was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR000003541).
PMCID: PMC3482551  PMID: 22994941
Miriplatin; Hepatocellular carcinoma; Cisplatin powder; Phase I clinical trial
3.  Heritability of Nonalcoholic Fatty Liver Disease 
Gastroenterology  2009;136(5):1585-1592.
Background & Aims
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the United States. The etiology is believed to be multi-factorial with a substantial genetic component; however, the heritability of NAFLD is undetermined. Therefore, a familial aggregation study was performed to test the hypothesis that NAFLD is highly heritable.
Overweight children with biopsy-proven NAFLD and overweight children without NAFLD served as probands. Family members were studied including magnetic resonance imaging to quantify liver fat fraction. Fatty liver was defined as a liver fat fraction ≥ 5%. Etiologies for fatty liver other than NAFLD were excluded. Narrow-sense heritability estimates for fatty liver (dichotomous) and fat fraction (continuous) were calculated using variance components analysis adjusted for covariate effects.
Fatty liver was present in 17% of siblings and 37% of parents of overweight children without NAFLD. Fatty liver was significantly more common in siblings (59%) and parents (78%) of children with NAFLD. Liver fat fraction was correlated with body mass index (BMI), although the correlation was significantly stronger for families of children with NAFLD than those without NAFLD. Adjusted for age, sex, race, and BMI, heritability of fatty liver was 1.000 and of liver fat fraction 0.386.
Family members of children with NAFLD should be considered at high risk for NAFLD. These data suggest that familial factors are a major determinant of whether an individual has NAFLD. Studies examining the complex relations between genes and environment in the development and progression of NAFLD are warranted.
PMCID: PMC3397140  PMID: 19208353
magnetic resonance; genetics; family; obesity; fatty liver
4.  Constraining the Initial Phase in Water-Fat Separation 
Magnetic resonance imaging  2010;29(2):216-221.
An algorithm is described for use in chemical shift based water-fat separation to constrain the phase of both species to be equal at an echo-time of zero. This constraint is physically reasonable since the initial phase should be a property of the excitation pulse and receiver coil only. The advantages of phase-constrained water-fat separation, namely improved noise performance and/or reduced data requirements (fewer echos), are demonstrated in simulations and experiments.
PMCID: PMC3053064  PMID: 21159457
Water-Fat Separation; Dixon; Chemical Shift; Phase
5.  Assessment of Liver Fat Quantification in the Presence of Iron 
Magnetic resonance imaging  2010;28(6):767-776.
This study assesses the stability of magnetic resonance (MR) liver fat measurements against changes in T2* due to the presence of iron, which is a confound for accurate quantification. The liver T2* was experimentally shortened by intravenous infusion of a super paramagnetic iron oxide (SPIO) contrast agent. Low flip angle multi-echo gradient echo sequences were performed before, during, and after infusion. The liver fat fraction (FF) was calculated in co-localized regions-of-interest using T2* models that assumed no decay, monoexponential decay and biexponential decay. Results show that, when T2* was neglected, there was a strong underestimation of the computed FF and with monoexponential decay there was a weak overestimation of FF. Curve-fitting using the biexponential decay was found to be problematic. The overestimation of FF may be due to remaining deficiencies in the model, although is unlikely to be important for clinical diagnosis of steatosis.
PMCID: PMC2924146  PMID: 20409663
6.  The Effect of PRESS and STEAM Sequences on Magnetic Resonance Spectroscopic Liver Fat Quantification 
To compare PRESS and STEAM MR spectroscopy for assessment of liver fat in human subjects.
Materials and Methods
Single-voxel (20×20×20 mm) PRESS and STEAM spectra were obtained at 1.5T in 49 human subjects with known or suspected fatty liver disease. PRESS and STEAM sequences were obtained with fixed TR (1500 ms) and different TE (5 PRESS spectra between TE 30–70 ms, 5 STEAM spectra between TE 20–60 ms). Spectra were quantified and T2 and T2-corrected peak area were calculated by different techniques. The values were compared for PRESS and STEAM.
Water T2 values from PRESS and STEAM were not significantly different (p =0.33). Fat peak T2s were 25–50% shorter on PRESS than on STEAM (p <0.02 for all comparisons) and there was no correlation between T2s of individual peaks. PRESS systematically overestimated the relative fat peak areas (by 7–263%) compared to STEAM (p <0.005 for all comparisons). The peak area given by PRESS was more dependent on the T2-correction technique than STEAM.
Measured liver fat depends on the MRS sequence used. Compared to STEAM, PRESS underestimates T2 values of fat, overestimates fat fraction, and provides a less consistent fat fraction estimate, probably due to J coupling effects.
PMCID: PMC2982807  PMID: 19557733
Liver Fat Quantification; Magnetic Resonance Spectroscopy; PRESS and STEAM; j-coupling
7.  Optimal Phased Array Combination for Spectroscopy 
Magnetic resonance imaging  2008;26(6):847-850.
A method is described for making a weighted linear combination of the spectra acquired by a phased array coil. Unlike most previous combination methods, no special reference points in the data are chosen to represent the coil weights. Instead all the data points are used, which results in more reliable estimation. The method uses singular value decomposition to identify the coils weights and extract the principal component of variation in the signal. Subsequent processing of the combined signal (e.g. Fourier transform, baseline correction, phasing) may proceed as per a single coil acquisition.
PMCID: PMC2868913  PMID: 18486392
Spectroscopy; SVD; Phased Array; Coils
8.  Relaxation Effects in the Quantification of Fat using Gradient Echo Imaging 
Magnetic resonance imaging  2008;26(3):347-359.
Quantification of fat has been investigated using images acquired from multiple gradient echos. The evolution of the signal with echo time and flip angle was measured in phantoms of known fat and water composition and in 21 research subjects with fatty liver. Data were compared to different models of the signal equation, in which each model makes different assumptions about the T1 and/or T2* relaxation effects. A range of T1, T2*, fat fraction and number of echos was investigated to cover situations of relevance to clinical imaging. Results indicate that quantification is most accurate at low flip angles (to minimize T1 effects) with a small number of echos (to minimize spectral broadening effects). At short echo times the spectral broadening effects manifest as a short apparent T2 for the fat component.
PMCID: PMC2386876  PMID: 18093781

Results 1-8 (8)