The curves plotted in Figure 3A,B for the 4° phase increment were incorrect. However, corrected Bloch equation simulations show a similar relationship between phase and T2 and do not alter the conclusions of our work. We have confirmed that the curves plotted for 1° and 2° phase increments are correct, as are all three curves plotted in Figure 3C. The authors regret this mistake and apologize for any inconvenience this may have caused.

Purpose Transverse relaxation time (T-2) mapping with MRI has a plethora of clinical and research applications. Current T-2 mapping techniques are based primarily on spin-echo (SE) relaxometry strategies that rely on the signal magnitude, and often suffer from lengthy acquisition times. In this work, we propose a phase-based T-2 mapping technique where T-2 information is encoded into the signal phase of rapid gradient echo (GRE) acquisitions. Theory Bloch equation simulations demonstrate that the phase of GRE acquisitions obtained with a very small inter-repetition RF phase increment has a strong monotonic dependence on T-2, resulting from coherent transverse magnetization. This T-2-dependent phase behavior forms the basis of the proposed T-2 mapping technique. To isolate T-2-dependent phase from background phase, at least 2 data sets with different RF phase increments are acquired. The proposed method can also be combined with chemical shift encoded MRI to separate water and fat signals. Methods The feasibility of the proposed technique was validated in a phantom experiment. In vivo feasibility was demonstrated in the brain, knee, abdomen, and pelvis. Comparisons were made with SE-based T-2 mapping, spectroscopy, and T-2 values from the literature. Results The proposed method produced accurate T-2 maps compared with SE-based T-2 mapping in the phantom. Good qualitative agreement was observed in vivo between the proposed method and the reference. T-2 measured in various anatomies agreed well with values reported in the literature. Conclusion A phase-based T-2 mapping technique was developed and its feasibility demonstrated in phantoms and in vivo.

PurposeChemical shift encoded (CSE)‐MRI enables quantification of proton‐density fat fraction (PDFF) as a biomarker of liver fat content. However, conventional 3D Cartesian CSE‐MRI methods require breath‐holding. A motion‐robust 2D Cartesian sequential method addresses this limitation but suffers from low SNR. In this work, a novel free breathing 2D Cartesian sequential CSE‐MRI method using a variable flip angle approach with centric phase encoding (VFA‐centric) is developed to achieve fat quantification with low bias, high SNR, and minimal blurring.MethodsNumerical simulation was performed for variable flip angle schedule design and preliminary evaluation of VFA‐centric method, along with several alternative flip angle designs. Phantom, adults (n = 8), and children (n = 27) were imaged at 3T. Multi‐echo images were acquired and PDFF maps were estimated. PDFF standard deviation was used as a surrogate for SNR.ResultsIn both simulation and phantom experiments, the VFA‐centric method enabled higher SNR imaging with minimal bias and blurring artifacts. High correlation (slope = 1.00, intercept = 0.04, = 0.998) was observed in vivo between the proposed VFA‐centric method obtained PDFF and reference PDFF (free breathing low‐flip angle 2D sequential acquisition). Further, the proposed VFA‐centric method (PDFF standard deviation = 1.5%) had a better SNR performance than the reference acquisition (PDFF standard deviation = 3.3%) with P < .001.ConclusionsThe proposed free breathing 2D Cartesian sequential CSE‐MRI method with variable flip angle approach and centric‐ordered phase encoding achieved motion robustness, low bias, high SNR compared to previous 2D sequential methods, and low blurring in liver fat quantification.

To demonstrate the feasibility of combined delayed-phase gadoxetic acid (GA) and gadobenate dimeglumine (GD) enhanced liver MRI for improved detection of liver metastases, and to optimize contrast agent dose, timing, and flip angle (FA). Fourteen healthy volunteers underwent liver MRI at 3.0T at two visits during which they received two consecutive injections: 1. GA (Visit 1 = 0.025 mmol/kg; Visit 2 = 0.05 mmol/kg) and 2. GD (both visits = 0.1 mmol/kg) 20 min after GA administration. Two sub-studies were performed: Experiment-1 Eight subjects underwent multi-phase breath-held 3D-fat-saturated T1-weighted spoiled gradient echo (SGRE) imaging to determine the optimal imaging window for the combined GA + GD protocol to create a homogeneously hyperintense liver and vasculature (“plain-white-liver”) with maximum contrast to muscle which served as a surrogate for metastatic lesions in both experiments. Experiment-2 Six subjects underwent breath-held 3D-fat-saturated T1-weighted SGRE imaging at three different FA to determine the optimal FA for best image contrast. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were evaluated. Experiment-1 The combined GA + GD protocol created a homogeneously hyperintense liver and vasculature with maximum CNR liver/muscle at approximately 60–120 s after automatic GD-bolus detection. Experiment-2 Flip angles between 25° and 35° at a dose of 0.025 mmol/kg GA provided the best combination that minimized liver/vasculature CNR, while maximizing liver/muscle CNR. CNR performance to achieve a “plain-white-liver” was superior with 0.025 mmol/kg GA compared to 0.05 mmol/kg. Combined GA + GD enhanced T1-weighted MRI is feasible to achieve a homogeneously “plain-white-liver”. Future studies need to confirm that this protocol can improve sensitivity of liver lesion detection in patients with metastatic liver disease.

PurposeTo develop and validate a T-1-corrected chemical-shift encoded MRI (CSE-MRI) method to improve noise performance and reduce bias for quantification of tissue proton density fat-fraction (PDFF). MethodsA variable flip angle (VFA)-CSE-MRI method using joint-fit reconstruction was developed and implemented. In computer simulations and phantom experiments, sources of bias measured using VFA-CSE-MRI were investigated. The effect of tissue T-1 on bias using low flip angle (LFA)-CSE-MRI was also evaluated. The noise performance of VFA-CSE-MRI was compared to LFA-CSE-MRI for liver fat quantification. Finally, a prospective pilot study in patients undergoing gadoxetic acid-enhanced MRI of the liver to evaluate the ability of the proposed method to quantify liver PDFF before and after contrast. ResultsVFA-CSE-MRI was accurate and insensitive to transmit B-1 inhomogeneities in phantom experiments and computer simulations. With high flip angles, phase errors because of RF spoiling required modification of the CSE signal model. For relaxation parameters commonly observed in liver, the joint-fit reconstruction improved the noise performance marginally, compared to LFA-CSE-MRI, but eliminated T-1-related bias. A total of 25 patients were successfully recruited and analyzed for the pilot study. Strong correlation and good agreement between PDFF measured with VFA-CSE-MRI and LFA-CSE-MRI (pre-contrast) was observed before (R-2 = 0.97; slope = 0.88, 0.81-0.94 95% confidence interval [CI]; intercept = 1.34, -0.77-1.92 95% CI) and after (R-2 = 0.93; slope = 0.88, 0.78-0.98 95% CI; intercept = 1.90, 1.01-2.79 95% CI) contrast. ConclusionJoint-fit VFA-CSE-MRI is feasible for T-1-corrected PDFF quantification in liver, is insensitive to B-1 inhomogeneities, and can eliminate T-1 bias, but with only marginal SNR advantage for T-1 values observed in the liver.

Objectives The aim of this study was to determine the relaxation properties of ferumoxytol, an off-label alternative to gadolinium-based contrast agents, under physiological conditions at 1.5 T and 3.0 T. Materials and Methods Ferumoxytol was diluted in gradually increasing concentrations (0.26–4.2 mM) in saline, human plasma, and human whole blood. Magnetic resonance relaxometry was performed at 37°C at 1.5 T and 3.0 T. Longitudinal and transverse relaxation rate constants (R1, R2, R2*) were measured as a function of ferumoxytol concentration, and relaxivities (r1, r2, r2*) were calculated. Results A linear dependence of R1, R2, and R2* on ferumoxytol concentration was found in saline and plasma with lower R1 values at 3.0 T and similar R2 and R2* values at 1.5 T and 3.0 T (1.5 T: r1 saline = 19.9 ± 2.3 s −1 mM −1 ; r1 plasma = 19.0 ± 1.7 s −1 mM −1 ; r2 saline = 60.8 ± 3.8 s −1 mM −1 ; r2 plasma = 64.9 ± 1.8 s −1 mM −1 ; r2* saline = 60.4 ± 4.7 s −1 mM −1 ; r2* plasma = 64.4 ± 2.5 s −1 mM −1 ; 3.0 T: r1 saline = 10.0 ± 0.3 s −1 mM −1 ; r1 plasma = 9.5 ± 0.2 s −1 mM −1 ; r2 saline = 62.3 ± 3.7 s −1 mM −1 ; r2 plasma = 65.2 ± 1.8 s −1 mM −1 ; r2* saline = 57.0 ± 4.7 s −1 mM −1 ; r2* plasma = 55.7 ± 4.4 s −1 mM −1 ). The dependence of relaxation rates on concentration in blood was nonlinear. Formulas from second-order polynomial fittings of the relaxation rates were calculated to characterize the relationship between R1 blood and R2 blood with ferumoxytol. Conclusions Ferumoxytol demonstrates strong longitudinal and transverse relaxivities. Awareness of the nonlinear relaxation behavior of ferumoxytol in blood is important for ferumoxytol-enhanced magnetic resonance imaging applications and for protocol optimization.

PURPOSE:To present a novel Optimized Diffusion-weighting Gradient waveform Design (ODGD) method for the design of minimum echo time (TE), bulk motion-compensated, and concomitant gradient (CG)-nulling waveforms for diffusion MRI. METHODS:ODGD motion-compensated waveforms were designed for various moment-nullings Mn (n = 0, 1, 2), for a range of b-values, and spatial resolutions, both without (ODGD-Mn ) and with CG-nulling (ODGD-Mn -CG). Phantom and in-vivo (brain and liver) experiments were conducted with various ODGD waveforms to compare motion robustness, signal-to-noise ratio (SNR), and apparent diffusion coefficient (ADC) maps with state-of-the-art waveforms. RESULTS:ODGD-Mn and ODGD-Mn -CG waveforms reduced the TE of state-of-the-art waveforms. This TE reduction resulted in significantly higher SNR (P < 0.05) in both phantom and in-vivo experiments. ODGD-M1 improved the SNR of BIPOLAR (42.8 ± 5.3 vs. 32.9 ± 3.3) in the brain, and ODGD-M2 the SNR of motion-compensated (MOCO) and Convex Optimized Diffusion Encoding-M2 (CODE-M2 ) (12.3 ± 3.6 vs. 9.7 ± 2.9 and 10.2 ± 3.4, respectively) in the liver. Further, ODGD-M2 also showed excellent motion robustness in the liver. ODGD-Mn -CG waveforms reduced the CG-related dephasing effects of non CG-nulling waveforms in phantom and in-vivo experiments, resulting in accurate ADC maps. CONCLUSIONS:ODGD waveforms enable motion-robust diffusion MRI with reduced TEs, increased SNR, and reduced ADC bias compared to state-of-the-art waveforms in theoretical results, simulations, phantoms and in-vivo experiments.

PurposeTo propose and evaluate an acetone–D2O phantom that has an extended range of apparent diffusion coefficient (ADC) for quantitative diffusion magnetic resonance imaging (MRI), as well as to compare its properties to previously described water‐based phantoms.Materials and MethodsThe proposed acetone–D2O, and previously described sucrose water solution and polyvinylpyrrolidone (PVP) water solution phantoms, were constructed in a number of concentrations between 0% and 50%. At 1.5T field strength, diffusion‐weighted MR spectroscopy (DW‐MRS), based on a point‐resolved spectroscopy (PRESS) acquisition, nondiffusion‐weighted stimulated echo acquisition mode (STEAM)‐MRS, and diffusion‐weighted echo‐planar imaging (DW‐EPI) were used to evaluate each phantom. The MR spectra, diffusion‐weighted signal decay pattern, tunability of ADC, and ADC range of each phantom were all evaluated.ResultsWhen placed in an ice‐water bath, all phantoms provided desirable signal properties, including single‐peak signal with Gaussian diffusion and tunable ADC. At 0°C, however, water‐based phantoms had ADC limited to less than 1.1·10−3 mm2·s−1 (0.2–1.1·10−3 mm2·s−1), while the proposed acetone‐based phantom had ADC values spanning a wider range (0.6–3.5·10−3 mm2·s−1).ConclusionThe proposed acetone–D2O phantom provided desirable signal properties over a wide range of ADCs with temperature controlled using an ice‐water bath.Level of Evidence: 2Technical Efficacy: Stage 1J. Magn. Reson. Imaging 2017;46:1683–1692.

PurposeTo evaluate the impact of different fat spectral models on proton density fat fraction quantification using chemical shift‐encoded MRI (CSE‐MRI).MethodsIn a simulation study, spectral models of fat were compared pairwise. Comparison of magnitude fitting and mixed fitting was performed over a range of echo times and fat fractions. In vivo acquisitions from 41 patients were reconstructed using seven published spectral models of fat. T2‐corrected stimulated echo acquisition mode MR spectroscopy was used as a reference.ResultsThe simulations demonstrated that imperfectly calibrated spectral models of fat result in biases that depend on echo times and fat fraction. Mixed fitting was more robust against this bias than magnitude fitting. Multipeak spectral models showed much smaller differences among themselves than from the single‐peak spectral model. In vivo studies showed that all multipeak models agreed better (for mixed fitting, the slope ranged from 0.967 to 1.045 using linear regression) with the reference standard than the single‐peak model (for mixed fitting, slope = 0.76).ConclusionIt is essential to use a multipeak fat model for accurate quantification of fat with CSE‐MRI. Furthermore, fat quantification techniques using multipeak fat models are comparable, and no specific choice of spectral model has been shown to be superior to the rest. Magn Reson Med 75:845–851, 2016. © 2015 Wiley Periodicals, Inc.

OBJECTIVE:The aim of this study was to investigate the effect of mutations of the forkhead transcription factor 2 (FOXL2) gene on the primary and secondary structure of the coded protein and seek for the molecular mechanism of blepharophimosis-ptosis-epicanthus inversus syndrome (BPES).METHODS:The genomic DNA was extracted from peripheral blood of 7 clinically diagnosed BPES patients, PCR amplification of FOXL2 coding region and 5' untranslated region were performed. Sequence analysis was performed using the PCR or cloning products. The structure of the protein was predicted with PDH and ExPASy software, and the difference between the normal and the mutational protein was analyzed.RESULTS:A 901- 930 dup 30 mutation of FOXL2 was found in two patients from a BPES family of type II and a sporadic case, and no any mutations were detected in normal control. Analysis of the primary structure displayed that the molecular weight of the protein coded by the mutated gene was greater than the normal, but both have the same isoelectric point. Analysis of the secondary structure showed that FOXL2 was a transmembrane protein with a polyalanine tract which contained a alpha-helix. When the polyalanine tract expanded, the helix region extended, as a result, the proportion of alpha-helix increased by 4.1%, but the proportions of beta-pleated sheet and random coil decreased correspondingly.CONCLUSION:Our results suggest that the 901 - 930 dup 30 mutation of FOXL2 is a novel finding. Moreover, this mutation causes great changes in the primary and secondary structure of the coded protein, which may be the molecular pathogenesis of BPES.

Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is an autosomal dominant disorder characterized by blepharophimosis, ptosis and epicanthus inversus. Based on the presence and absence of premature ovarian failure, two clinical types have been distinguished. Both types of BPES have been mapped to chromosome 3q23 and are mostly due to mutations of a forkhead transcription factor FOXL2 gene which locates at this region. We screened for FOXL2 mutations in Chinese patients with BPES. A novel mutation (g.901-930dup30) which could result in an expansion of the polyalanine tract was found in two BPES type II families and one sporadic case. In addition, a new g.952delC mutation was identified in two patients from a BPES family of undetermined type. The previously reported g.892C>T (p.Q219X) was also found in 12 patients from a large BPES family of type I. No mutations were detected in three other BPES families and three sporadic cases. So we speculate that in a fraction of the BPES patients the genetic defect may represent a change in gene dosage or a rearrangement outside the transcription unit of FOXL2.

OBJECTIVE To screen mutations in the forkhead transcriptional factor 2 gene (FOXL2) in six Chinese families with blepharophimosis, ptosis, and epicanthus inversus syndrome(BPES). METHODS PCR amplification and direct sequencing of the FOXL2 coding region in genomic DNA were performed in affected patients and 80 healthy controls. BLAST analysis of the sequence was made on Internet. RESULTS A novel 951-953(delC) was found in the two affected patients of a Chinese family with BPES. No mutations were found in the healthy controls. The 951-953(delC) may cause a frameshift mutation after codon 238 that exists downstream of the forkhead domain, resulting in the production of truncated proteins. CONCLUSION These findings indicated that the 951-953(delC) deletion mutation in the two patients resulted in truncated proteins and hence led to their BPES. To the authors' knowledge, the 951-953(delC) in FOXL2 has not been previously reported.

Spindle is a specific substructure in cell during meiosis and gamete maturity division and its structure and function directly influence the development, differentiation, growth and reproduction of individuals. Recent researches also show that mouse Mos/MAPK pathway is tightly related to spindlin phosphorylation. We report that ( i) a novel gene encoding a putative human spindlin (SPIN) has been cloned, which is highly homologous to mouse Spin; (ii) tissue expression pattern of SPIN, shows that SPIN is highly expressed as a 4.8 kb transcript in ovary, testis, heart, brain, kidney, pancreas, placenta and spleen, also with a specific 2.0 kb transcript in testis, but there is no hybridization band in thymus and small intestine, and (iii) SPIN has been mapped to human chromosome 9q22.1-22.3 by Radiation Hybrid Mapping. This novel gene was registered in GenBank as SPIN with accession number AF087864.

This paper discusses the trend of the development of highway traffic as part of the development of the auto industry, support from international financial organizations and development of the rural economy in combination with the dual property of highway traffic and sustainable development to offer the basis for making out the plan for the highway network of Jilin Province in the first 15 years of the 21st Century. It proposes the strategic objective of sustainable development by citing the figures from the Organization for Economic Cooperation and Development (OECD)'s forecast for the economic development of Asia and the world in combination with the features of socioeconomic development and development of the highway traffic economy in Jilin Province.

HTGEKP, which is rather conservative especially in the link region between two zinc finger motifs （TGEKP）

Identification of novel human genes is one of the main contents of human genome researchproject. Zinc finger protein is a kind of transcriptional factor. Nearly 200 human zinc finger pro-tein genes have been cloned since 1983. These genes or gene products have been found to be in-volved in some important biological process such as germ formation, embryonic development andcell differentiation. In addition, some structural variation of some zinc finger genes were also re-