301
|
Posse S, Otazo R, Dager SR, Alger J. MR spectroscopic imaging: Principles and recent advances. J Magn Reson Imaging 2012. [DOI: 10.1002/jmri.23945] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
|
302
|
Miyazaki M, Wheaton A, Kitane S. Enhanced fat suppression technique for breast imaging. J Magn Reson Imaging 2012; 38:981-6. [PMID: 23172831 DOI: 10.1002/jmri.23932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 10/02/2012] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To evaluate a new fat suppression technique using multiple fat suppression pulses intended for breast dynamic contrast-enhanced (DCE) imaging using segmented three-dimensional fast field echo (FFE). MATERIALS AND METHODS The effect of multiple spectrally-selective fat suppression radiofrequency pulses was modeled using numerical Bloch-equation solutions for the following fat suppression techniques: spectral-selective inversion recovery (SPIR: one pulse), double fat suppression (DFS: two pulses, combining one SPIR pulse and one CHESS pulse), and triple fat suppression (TFS: three pulses, combining one SPIR pulse and two CHESS pulses). The simulation data were evaluated in terms of fat suppression performance, scan time, and specific absorption rate (SAR) relative to the SPIR technique. The DFS technique was selected as the optimal technique based on the efficacy of fat suppression versus the costs of scan time and SAR. The DFS technique was compared with SPIR in six volunteer studies using segmented T1 -weighted three-dimensional FFE. RESULTS The DFS technique produced sufficient fat suppression using only two segments (two fat suppression shots). Breast DCE precontrast images using DFS presented uniform fat suppression compared with SPIR in both axial and sagittal scans in all six volunteers. CONCLUSION DFS is a promising fat suppression technique for breast imaging even in regions with B1 (+) inhomogeneity.
Collapse
Affiliation(s)
- Mitsue Miyazaki
- Toshiba Medical Research Institute, Vernon Hills, Illinois, USA; Toshiba Medical Systems Corporation, Otawara Tochigi, Japan
| | | | | |
Collapse
|
303
|
Srikanthan P, Singhal A, Lee CC, Nagarajan R, Wilson N, Roberts CK, Hahn TJ, Thomas MA. Characterization of Intra-myocellular Lipids using 2D Localized Correlated Spectroscopy and Abdominal Fat using MRI in Type 2 Diabetes. MAGNETIC RESONANCE INSIGHTS 2012; 5:29-36. [PMID: 23471581 DOI: 10.4137/mri.s10489] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A major goal of this pilot study was to quantify intramyocellular lipids (IMCL), extramyocellular lipids (EMCL), unsaturation index (UI) and metabolites such as creatine (Cr), choline (Ch) and carnosine (Car), in the soleus muscle using two-dimensional (2D) localized correlated spectroscopy (L-COSY). Ten subjects with type 2 diabetes (T2D), controlled by lifestyle management alone, and 9 healthy control subjects, were studied. In T2D patients only, the following measurements were obtained: body mass index (BMI); waist circumference (WC); abdominal visceral and subcutaneous fat quantified using breath-held magnetic resonance imaging (MRI); a fasting blood draw for assessment of glucose, insulin, and estimation of homeostasis model assessment of insulin resistance (HOMA-IR), HbA1c, and high-sensitivity c-reactive protein (hs-CRP). Analysis of the soleus muscle 2D L-COSY spectral data showed significantly elevated IMCL ratios with respect to Cr and decreased IMCL UI in T2D when compared to healthy subjects (P < 0.05). In T2D subjects, Pearson correlation analysis showed a positive correlation of IMCL/Cr with EMCL/Cr (0.679, P < 0.05) and HOMA-IR (0.633, P < 0.05), and a non-significant correlation of visceral and subcutaneous fat with magnetic resonance spectroscopy (MRS) and other metrics. Characterization of muscle IMCL and EMCL ratios, UI, and abdominal fat, may be useful for the noninvasive assessment of the role of altered lipid metabolism in the pathophysiology of T2D, and for assessment of the effects of future therapeutic interventions designed to alter metabolic dysfunction in T2D.
Collapse
|
304
|
Prescot AP, Renshaw PF. Two-dimensional J-resolved proton MR spectroscopy and prior knowledge fitting (ProFit) in the frontal and parietal lobes of healthy volunteers: assessment of metabolite discrimination and general reproducibility. J Magn Reson Imaging 2012; 37:642-51. [PMID: 23055387 DOI: 10.1002/jmri.23848] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 08/30/2012] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To investigate human brain metabolite discriminability and general measurement reproducibility of two-dimensional (2D) J-resolved (1)H MRS and Prior Knowledge Fitting (ProFit). MATERIALS AND METHODS 2D J-resolved (1)H MRS spectra were acquired from the anterior cingulate cortex (ACC) and the parietal-occipital cortex (POC) of 10 healthy subjects at a magnetic field strength of 2.9 Tesla. Amplitude correlation matrices were constructed for each subject and brain region to assess metabolite discriminability. ProFit-estimated metabolite peak areas were normalized to a water reference signal, and intra- and inter-subject reproducibility was evaluated. RESULTS Favorable between-metabolite correlation coefficients (<20%) were observed for a range of metabolites. Lower correlation coefficients between a given pair of metabolite estimates were consistently observed for POC metabolites. The group mean correlation coefficient existing between glutamate and glutamine was calculated as -18% and -13% for ACC and POC, respectively. Most ACC and POC metabolites showed intra- and inter-subject CV values of <15% and <20%, respectively. CONCLUSION The observed Glu and Gln signal discrimination makes these techniques suitable for investigating a variety of psychiatric disorders. Intra- and inter-subject metabolite level reproducibility was comparable to the existing literature findings. These data serve as a valuable benchmark for assessing future modifications to 2D (1)H MRS data acquisition and ProFit analysis.
Collapse
Affiliation(s)
- Andrew P Prescot
- Brain Institute, Department of Radiology, University of Utah School of Medicine, Salt Lake City, Utah 84108, USA.
| | | |
Collapse
|
305
|
Cui X, Bao J, Huang Y, Cai S, Chen Z. In vivo spatially localized high resolution 1H MRS via intermolecular single-quantum coherence of rat brain at 7 T. J Magn Reson Imaging 2012; 37:359-64. [PMID: 23034817 DOI: 10.1002/jmri.23839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 08/24/2012] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To compare the conventional localized point-resolved spectroscopy (PRESS) with localized 2D intermolecular single-quantum coherence (iSQC) magnetic resonance spectroscopy (MRS) and obtain in vivo MRS spectrum of rat brain using the latter technique. MATERIALS AND METHODS A brain phantom, an intact pig brain tissue, and mature Sprague-Dawley rat were studied by PRESS, Nano magic-angle spinning spectroscopy, and iSQC MRS. RESULTS Using PRESS, high-resolution MRS can be obtained from the brain phantom and pig brain tissue with a small voxel in a relatively homogeneous field. When a large voxel is selected, the field homogeneity is distinctly reduced. No useful information is obtained from the PRESS spectra. However, using the iSQC MRS, high-resolution spectra can be obtained from the two samples with a relatively large voxel. In the same way, an iSQC MRS spectrum can be obtained from a relatively large voxel of in vivo rat brain with a comparable resolution to the PRESS spectrum with a small voxel. CONCLUSION Compared to PRESS, the iSQC MRS may be more feasible and promising for detection of strongly structured tissues with relatively large voxels.
Collapse
Affiliation(s)
- Xiaohong Cui
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | | | | | | | | |
Collapse
|
306
|
Van Cauter S, Sima DM, Luts J, ter Beek L, Ribbens A, Peeters RR, Osorio Garcia MI, Li Y, Sunaert S, Van Gool SW, Van Huffel S, Himmelreich U. Reproducibility of rapid short echo time CSI at 3 tesla for clinical applications. J Magn Reson Imaging 2012; 37:445-56. [PMID: 23011898 DOI: 10.1002/jmri.23820] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 08/14/2012] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To validate the reproducibility of a chemical shift imaging (CSI) acquisition protocol with parallel imaging, using automated repositioning software. MATERIALS AND METHODS Ten volunteers were imaged three times on two different 3 Tesla (T) MRI scanners, receiving anatomical imaging and two identical CSI measurements, using automated repositioning software for consistent repositioning of the CSI grid. Offcenter parameters of the CSI plane were analyzed. Coefficients of variation (CoV), Cramér-Rao lower bounds (CRLB), intraclass correlation coefficients (ICC), and coefficients of repeatability (CoR) for immediate repetition and between scanners were calculated for N-acetylaspartate, total choline, creatine, myo-inositol (Myo) and glutamine+glutamate (Glx). Proportions of variance reflecting the effect of voxel location, volunteer, repetition, time instance and scanner were calculated from an analysis of variance analysis. RESULTS The offcenter vector and angulations of the CSI grid differed less than 1 mm and 2° between all measurements. The mean CoV and CRLB were less than 30% for all metabolites, except for Myo. The variance due to voxel location in the volume of interest and the error represent the largest contributions in variability. The ICC is the lowest for Myo and Glx. CoR for immediate repetition and between scanners display values between 22 and 83%. CONCLUSION We propose a CSI protocol with acceptable reproducibility, applicable in clinical routine.
Collapse
Affiliation(s)
- Sofie Van Cauter
- Department of Radiology, University Hospitals Leuven, Leuven, Belgium.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
307
|
Mountford CE, Schuster C, Baltzer PA, Malycha P, Kaiser WA. MR spectroscopy in the breast clinic is improving. Eur J Radiol 2012; 81 Suppl 1:S104-6. [DOI: 10.1016/s0720-048x(12)70042-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
308
|
L-COSY of breast cancer at 3T. Eur J Radiol 2012; 81 Suppl 1:S129-31. [DOI: 10.1016/s0720-048x(12)70053-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
309
|
Ouwerkerk R, Pettigrew RI, Gharib AM. Liver metabolite concentrations measured with 1H MR spectroscopy. Radiology 2012; 265:565-75. [PMID: 22891360 DOI: 10.1148/radiol.12112344] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE To determine the feasibility of measuring choline and glycogen concentrations in normal human liver in vivo with proton (hydrogen 1 [1H]) magnetic resonance (MR) spectroscopy. MATERIALS AND METHODS Signed consent to participate in an institutional review board-approved and HIPAA-compliant study was obtained from 46 subjects (mean age, 46 years±17 [standard deviation]; 24 women) consecutively recruited during 285 days. Navigator-gated MR images were used to select 8-mL volumes for point-resolved spectroscopy (PRESS) with a 35-msec echo time. Line widths were minimized with fast breath-hold B0 field mapping and further manual shimming. Navigator-gated spectra were recorded with and without water suppression to determine metabolite concentrations with water signals as an internal reference. In three subjects, echo time was varied to determine the glycogen and choline T2. Linear regression analysis was used to examine relations between choline, hepatic lipid content, body mass index, glycogen content, and age. RESULTS Choline concentrations could be determined in 46 of 48 studies and was found to be 8.6 mmol per kilogram of wet weight±3.1 (range, 3.8-17.6; n=44). Twenty-seven spectra in 25 individuals with narrow line widths and low lipid content were adequate for quantitation of glycogen. The glycogen (glucosyl unit) concentration was 38.1 mmol/kg wet weight±14.4. The T2 of combined glycogen peaks in the liver of three subjects was 36 msec±8. Choline levels showed a weak but significant correlation with glycogen (r2=0.15; P<.05) but not with lipid content. CONCLUSION Navigator-gated and gradient-echo shimmed PRESS 1H MR spectroscopy may allow quantification of liver metabolites that are important for understanding and identifying disorders of glucose and lipid metabolism.
Collapse
Affiliation(s)
- Ronald Ouwerkerk
- Biomedical and Metabolic Imaging Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 10 Center Dr, CRC Building 10, Room 3-5340, MSC 1263, Bethesda, MD 20892-1263, USA.
| | | | | |
Collapse
|
310
|
Pola A, Sadananthan SA, Yaligar J, Nagarajan V, Han W, Kuchel PW, Velan SS. Skeletal muscle lipid metabolism studied by advanced magnetic resonance spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2012; 65:66-76. [PMID: 22781315 DOI: 10.1016/j.pnmrs.2012.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 02/08/2012] [Indexed: 06/01/2023]
Affiliation(s)
- Arunima Pola
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, Singapore
| | | | | | | | | | | | | |
Collapse
|
311
|
Snyder J, Haas M, Dragonu I, Hennig J, Zaitsev M. Three-dimensional arbitrary voxel shapes in spectroscopy with submillisecond TEs. NMR IN BIOMEDICINE 2012; 25:1000-1006. [PMID: 22290622 DOI: 10.1002/nbm.2764] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 11/24/2011] [Accepted: 11/28/2011] [Indexed: 05/31/2023]
Abstract
A novel spectroscopic method for submillisecond TEs and three-dimensional arbitrarily shaped voxels was developed and applied to phantom and in vivo measurements, with additional parallel excitation (PEX) implementation. A segmented spherical shell excitation trajectory was used in combination with appropriate radiofrequency weights for target selection in three dimensions. Measurements in a two-compartment phantom realized a TE of 955 µs, excellent spectral quality and comparable signal-to-noise ratios between accelerated (R = 2) and nonaccelerated modes. The two-compartment model allowed a comparison of the spectral suppression qualities of the method and, although outer volume signals were suppressed by factors of 1434 and 2246 compared with the theoretical unsuppressed case for the clinical and PEX modes, respectively, incomplete suppression of the outer volume (935 cm(3) compared with a target volume of 5.86 cm(3) ) resulted in a spectral contamination of 10.2% and 6.5% compared with the total signal. The method was also demonstrated in vivo in human brain on a clinical system at TE = 935 µs with good signal-to-noise ratio and spatial and spectral selection, and included LCModel relative quantification analysis. Eight metabolites showed significant fitting accuracy, including aspartate, N-acetylaspartylglutamate, glutathione and glutamate.
Collapse
Affiliation(s)
- Jeff Snyder
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany.
| | | | | | | | | |
Collapse
|
312
|
Labadie C, Hetzer S, Schulz J, Mildner T, Aubert-Frécon M, Möller HE. Center-out echo-planar spectroscopic imaging with correction of gradient-echo phase and time shifts. Magn Reson Med 2012; 70:16-24. [PMID: 22847848 DOI: 10.1002/mrm.24428] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 06/29/2012] [Accepted: 07/02/2012] [Indexed: 01/04/2023]
Abstract
A procedure to prevent the formation of image and spectral Nyquist ghosts in echo-planar spectroscopic imaging is introduced. It is based on a novel Cartesian center-out echo-planar spectroscopic imaging trajectory, referred to as EPSICO, and combined with a correction of the gradient-echo phase and time shifts. Processing of homogenous sets of forward and reflected echoes is no longer necessary, resulting in an optimized spectral width. The proposed center-out trajectory passively prevents the formation of Nyquist ghosts by privileging the acquisition of the center k-space line with forward echoes at the beginning of an echo-planar spectroscopic imaging dwell time and by ensuring that all k-space lines and their respective complex conjugates are acquired at equal time intervals. With the proposed procedure, concentrations of N-acetyl aspartate, creatine, choline, glutamate, and myo-inositol were reliably determined in human white matter at 3 T.
Collapse
Affiliation(s)
- Christian Labadie
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | | | | | | | | | | |
Collapse
|
313
|
Venkatesh BA, Lima JAC, Bluemke DA, Lai S, Steenbergen C, Liu CY. MR proton spectroscopy for myocardial lipid deposition quantification: a quantitative comparison between 1.5T and 3T. J Magn Reson Imaging 2012; 36:1222-30. [PMID: 22826193 DOI: 10.1002/jmri.23761] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 06/22/2012] [Indexed: 01/28/2023] Open
Abstract
PURPOSE To evaluate 3T magnetic resonance spectroscopy (MRS)-derived myocardial fat-signal fractions in comparison with those from 1.5T MRS. MATERIALS AND METHODS We conducted phantom, ex vivo and in vivo myocardial specimen evaluations at both 1.5T and 3T using (1)H-MRS. A phantom with nine fat-water emulsions was constructed to assess the accuracy of the spectroscopy measurements. Ex vivo spectroscopy data were acquired in 70 segments from 21 autopsy heart slices. In vivo spectroscopy data were acquired in the interventricular septum from 22 human volunteers. RESULTS Phantom experiments demonstrated that 1.5T and 3T measurements were highly correlated with the reference values (r = 0.78, P < 0.05). The ex vivo and in vivo experiments demonstrated an increase in signal-to-noise ratio (SNR) of 45 ± 73% and 76 ± 72% at 3T compared to 1.5T (P < 0.05). The mean fat-signal fraction was similar at 3T and 1.5T (1.11 ± 1.18 vs. 1.00 ± 1.09, respectively, P = NS) in ex vivo studies but were significantly different in the in vivo studies (2.47 ± 1.46 vs. 1.56 ± 1.34, P < 0.05). The fat-signal fractions from 3T and 1.5T correlated fairly well in all experiments. CONCLUSION 3T MRS has significantly greater SNR and could potentially be more accurate as compared to 1.5T for quantification of myocardial fat fraction in in vivo studies.
Collapse
|
314
|
Zhao C, Bolan PJ, Royce M, Lakkadi N, Eberhardt S, Sillerud L, Lee SJ, Posse S. Quantitative mapping of total choline in healthy human breast using proton echo planar spectroscopic imaging (PEPSI) at 3 Tesla. J Magn Reson Imaging 2012; 36:1113-23. [PMID: 22782667 DOI: 10.1002/jmri.23748] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 06/01/2012] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To quantitatively measure tCho levels in healthy breasts using Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI). MATERIALS AND METHODS The two-dimensional mapping of tCho at 3 Tesla across an entire breast slice using PEPSI and a hybrid spectral quantification method based on LCModel fitting and integration of tCho using the fitted spectrum were developed. This method was validated in 19 healthy females and compared with single voxel spectroscopy (SVS) and with PRESS prelocalized conventional Magnetic Resonance Spectroscopic Imaging (MRSI) using identical voxel size (8 cc) and similar scan times (∼7 min). RESULTS A tCho peak with a signal to noise ratio larger than 2 was detected in 10 subjects using both PEPSI and SVS. The average tCho concentration in these subjects was 0.45 ± 0.2 mmol/kg using PEPSI and 0.48 ± 0.3 mmol/kg using SVS. Comparable results were obtained in two subjects using conventional MRSI. High lipid content in the spectra of nine tCho negative subjects was associated with spectral line broadening of more than 26 Hz, which made tCho detection impossible. Conventional MRSI with PRESS prelocalization in glandular tissue in two of these subjects yielded tCho concentrations comparable to PEPSI. CONCLUSION The detection sensitivity of PEPSI is comparable to SVS and conventional PRESS-MRSI. PEPSI can be potentially used in the evaluation of tCho in breast cancer. A tCho threshold concentration value of ∼0.7 mmol/kg might be used to differentiate between cancerous and healthy (or benign) breast tissues based on this work and previous studies.
Collapse
Affiliation(s)
- Chenguang Zhao
- Department of Neurology and UNM Cancer Center, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, USA.
| | | | | | | | | | | | | | | |
Collapse
|
315
|
Bogner W, Gruber S, Trattnig S, Chmelik M. High-resolution mapping of human brain metabolites by free induction decay (1)H MRSI at 7 T. NMR IN BIOMEDICINE 2012; 25:873-82. [PMID: 22190245 DOI: 10.1002/nbm.1805] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 05/26/2011] [Accepted: 09/27/2011] [Indexed: 05/06/2023]
Abstract
This work describes a new approach for high-spatial-resolution (1)H MRSI of the human brain at 7 T. (1)H MRSI at 7 T using conventional approaches, such as point-resolved spectroscopy and stimulated echo acquisition mode with volume head coils, is limited by technical difficulties, including chemical shift displacement errors, B(0)/B(1) inhomogeneities, a high specific absorption rate and decreased T(2) relaxation times. The method presented here is based on free induction decay acquisition with an ultrashort acquisition delay (TE*) of 1.3 ms. This allows full signal detection with negligible T(2) decay or J-modulation. Chemical shift displacement errors were reduced to below 5% per part per million in the in-slice direction and were eliminated in-plane. The B(1) sensitivity was reduced significantly and further corrected using flip angle maps. Specific absorption rate requirements were well below the limit (~20 % = 0.7 W/kg). The suppression of subcutaneous lipid signals was achieved by substantially improving the point-spread function. High-quality metabolic mapping of five important brain metabolites was achieved with high in-plane resolution (64 × 64 matrix with a 3.4 × 3.4 × 12 mm(3) nominal voxel size) in four healthy subjects. The ultrashort TE* increased the signal-to-noise ratio of J-coupled resonances, such as glutamate and myo-inositol, several-fold to enable the mapping of even these metabolites with high resolution. Four measurement repetitions in one healthy volunteer provided proof of the good reproducibility of this method. The high spatial resolution allowed the visualization of several anatomical structures on metabolic maps. Free induction decay MRSI is insensitive to T(2) decay, J-modulation, B(1) inhomogeneities and chemical shift displacement errors, and overcomes specific absorption rate restrictions at ultrahigh magnetic fields. This makes it a promising method for high-resolution (1)H MRSI at 7 T and above.
Collapse
Affiliation(s)
- W Bogner
- Department of Radiology, MR Center of Excellence, Medical University Vienna, Vienna, Austria
| | | | | | | |
Collapse
|
316
|
Koda M, Furihata K, Wei F, Miyakawa T, Tanokura M. NMR-based metabolic profiling of rice wines by F(2)-selective total correlation spectra. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:4818-4825. [PMID: 22530947 DOI: 10.1021/jf3008647] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this study, we performed NMR-based metabolic profiling of major rice wines (Japanese sake, Chinese Shaoxing wine, and Korean makgeolli). In the (1)H NMR spectra, the rice wines showed broad resonances in the region of about 7.9-9.0 ppm. These resonances showed many and complex correlations with approximately 0.5-4.5 ppm in the F(2)-selective TOCSY (total correlation spectroscopy) spectra, and these correlations were attributed mainly to peptides. These spectral patterns were characteristic of individual rice wines, and the combination of F(2)-selective TOCSY spectra and principal component analysis enabled us to classify the rice wine species. Furthermore, it also provided information about raw materials, namely, what type of koji (rice koji or wheat koji) was used. These spectra may be useful as a new "fingerprint" for quality control or food authentication.
Collapse
Affiliation(s)
- Masanori Koda
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | | | | | | | | |
Collapse
|
317
|
Furuyama JK, Wilson NE, Burns BL, Nagarajan R, Margolis DJ, Thomas MA. Application of compressed sensing to multidimensional spectroscopic imaging in human prostate. Magn Reson Med 2012; 67:1499-505. [PMID: 22505247 DOI: 10.1002/mrm.24265] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/27/2012] [Accepted: 02/28/2012] [Indexed: 11/07/2022]
Abstract
The application of compressed sensing is demonstrated in a recently implemented four-dimensional echo-planar based J-resolved spectroscopic imaging sequence combining two spatial and two spectral dimensions. The echo-planar readout simultaneously acquires one spectral and one spatial dimension. Therefore, the compressed sensing undersampling is performed along the indirectly acquired spatial and spectral dimensions, and the reconstruction is performed using the split Bregman algorithm, an efficient TV-minimization solver. The four-dimensional echo-planar-based J-resolved spectroscopic imaging data acquired in a prostate phantom containing metabolites at physiological concentrations are accurately reconstructed with as little as 20% of the original data. Experimental data acquired in six healthy prostates using the external body matrix "receive" coil on a 3T magnetic resonance imaging scanner are reconstructed with acquisitions using only 25% of the Nyquist-Shannon required amount of data, indicating the potential for a 4-fold acceleration factor in vivo, bringing the required scan time for multidimensional magnetic resonance spectroscopic imaging within clinical feasibility.
Collapse
Affiliation(s)
- Jon K Furuyama
- Department of Radiological Sciences, University of California, Los Angeles, California 90095, USA
| | | | | | | | | | | |
Collapse
|
318
|
Zhu J, Sova P, Xu Q, Dombek KM, Xu EY, Vu H, Tu Z, Brem RB, Bumgarner RE, Schadt EE. Stitching together multiple data dimensions reveals interacting metabolomic and transcriptomic networks that modulate cell regulation. PLoS Biol 2012; 10:e1001301. [PMID: 22509135 PMCID: PMC3317911 DOI: 10.1371/journal.pbio.1001301] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 02/20/2012] [Indexed: 01/22/2023] Open
Abstract
DNA variation can be used as a systematic source of perturbation in segregating populations as a way to infer regulatory networks via the integration of large-scale, high-dimensional molecular profiling data. Cells employ multiple levels of regulation, including transcriptional and translational regulation, that drive core biological processes and enable cells to respond to genetic and environmental changes. Small-molecule metabolites are one category of critical cellular intermediates that can influence as well as be a target of cellular regulations. Because metabolites represent the direct output of protein-mediated cellular processes, endogenous metabolite concentrations can closely reflect cellular physiological states, especially when integrated with other molecular-profiling data. Here we develop and apply a network reconstruction approach that simultaneously integrates six different types of data: endogenous metabolite concentration, RNA expression, DNA variation, DNA–protein binding, protein–metabolite interaction, and protein–protein interaction data, to construct probabilistic causal networks that elucidate the complexity of cell regulation in a segregating yeast population. Because many of the metabolites are found to be under strong genetic control, we were able to employ a causal regulator detection algorithm to identify causal regulators of the resulting network that elucidated the mechanisms by which variations in their sequence affect gene expression and metabolite concentrations. We examined all four expression quantitative trait loci (eQTL) hot spots with colocalized metabolite QTLs, two of which recapitulated known biological processes, while the other two elucidated novel putative biological mechanisms for the eQTL hot spots. It is now possible to score variations in DNA across whole genomes, RNA levels and alternative isoforms, metabolite levels, protein levels and protein state information, protein–protein interactions, and protein–DNA interactions, in a comprehensive fashion in populations of individuals. Interactions among these molecular entities define the complex web of biological processes that give rise to all higher order phenotypes, including disease. The development of analytical approaches that simultaneously integrate different dimensions of data is essential if we are to extract the meaning from large-scale data to elucidate the complexity of living systems. Here, we use a novel Bayesian network reconstruction algorithm that simultaneously integrates DNA variation, RNA levels, metabolite levels, protein–protein interaction data, protein–DNA binding data, and protein–small-molecule interaction data to construct molecular networks in yeast. We demonstrate that these networks can be used to infer causal relationships among genes, enabling the identification of novel genes that modulate cellular regulation. We show that our network predictions either recapitulate known biology or can be prospectively validated, demonstrating a high degree of accuracy in the predicted network.
Collapse
Affiliation(s)
- Jun Zhu
- Sage Bionetworks, Seattle, Washington, United States of America
- * E-mail: (JZ); (EES)
| | - Pavel Sova
- Department of Microbiology, University of Washington, Seattle Washington, United States of America
| | - Qiuwei Xu
- Safety Assessment, Merck & Co., Inc., West Point, Pennsylvania, United States of America
| | - Kenneth M. Dombek
- Department of Microbiology, University of Washington, Seattle Washington, United States of America
| | - Ethan Y. Xu
- Safety Assessment, Merck & Co., Inc., West Point, Pennsylvania, United States of America
| | - Heather Vu
- Safety Assessment, Merck & Co., Inc., West Point, Pennsylvania, United States of America
| | - Zhidong Tu
- Molecular Profiling, Merck Research Laboratories, Boston, Massachusetts, United States of America
| | - Rachel B. Brem
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, United States of America
| | - Roger E. Bumgarner
- Department of Microbiology, University of Washington, Seattle Washington, United States of America
| | - Eric E. Schadt
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York City, New York, United States of America
- * E-mail: (JZ); (EES)
| |
Collapse
|
319
|
Hehn M, Hiller W, Wagner T, Thiel J, Pasch H. Molar Mass and Microstructure Analysis of PI-b-PMMA Copolymers by SEC-NMR. MACROMOL CHEM PHYS 2012. [DOI: 10.1002/macp.201100645] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
320
|
Hess AT, Andronesi OC, Tisdall MD, Sorensen AG, van der Kouwe AJW, Meintjes EM. Real-time motion and B0 correction for localized adiabatic selective refocusing (LASER) MRSI using echo planar imaging volumetric navigators. NMR IN BIOMEDICINE 2012; 25:347-58. [PMID: 21796711 PMCID: PMC3261340 DOI: 10.1002/nbm.1756] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 05/24/2011] [Accepted: 06/01/2011] [Indexed: 05/11/2023]
Abstract
A method is presented to correct the effects of motion and motion-related B(0) perturbations on spectroscopic imaging in real time through the use of a volumetric navigator. It is demonstrated that, for an axial slice, lifting the chin significantly disrupts the B(0) homogeneity in the zero-order (frequency), first-order Y (coronal) axis and second-order ZY term. This volumetric navigator is able to measure and correct in real time both head pose and zero- to first-order B(0) inhomogeneities. The volumetric navigator was validated in six volunteers who deliberately lifted and then dropped their chin during the scan. These scans show that motion correction alone is not sufficient to recover the spectral quality. By applying real-time shim adjustments, spectral quality was fully recovered to linewidths below 0.08 ppm and the signal-to-noise ratio to within acceptable limits in five of six subjects. In the sixth subject, 83% of the spectra within the volume of interest were recovered, compared with the worst case nonshim-corrected scan, where none of the voxels fell within these quality bounds. It is shown that the use of a volumetric navigator comes at no additional cost to the scan time or spectral signal-to-noise ratio.
Collapse
Affiliation(s)
- Aaron T Hess
- MRC/UCT Medical Imaging Research Unit, Department of Human Biology, University of Cape Town, South Africa.
| | | | | | | | | | | |
Collapse
|
321
|
Andronesi OC, Gagoski BA, Adalsteinsson E, Sorensen AG. Correlation chemical shift imaging with low-power adiabatic pulses and constant-density spiral trajectories. NMR IN BIOMEDICINE 2012; 25:195-209. [PMID: 21774010 PMCID: PMC3261335 DOI: 10.1002/nbm.1730] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 03/21/2011] [Accepted: 03/21/2011] [Indexed: 05/31/2023]
Abstract
In this work we introduce the concept of correlation chemical shift imaging (CCSI). Novel CCSI pulse sequences are demonstrated on clinical scanners for two-dimensional Correlation Spectroscopy (COSY) and Total Correlation Spectroscopy (TOCSY) imaging experiments. To date there has been limited progress reported towards a feasible and robust multivoxel 2D COSY. Localized 2D TOCSY imaging is shown for the first time in this work. Excitation with adiabatic GOIA-W(16,4) pulses (Gradient Offset Independent Adiabaticity Wurst modulation) provides minimal chemical shift displacement error, reduced lipid contamination from subcutaneous fat, uniform optimal flip angles, and efficient mixing for coupled spins, while enabling short repetition times due to low power requirements. Constant-density spiral readout trajectories are used to acquire simultaneously two spatial dimensions and f(2) frequency dimension in (k(x),k(y),t(2)) space in order to speed up data collection, while f(1) frequency dimension is encoded by consecutive time increments of t(1) in (k(x),k(y),t(1),t(2)) space. The efficient spiral sampling of the k-space enables the acquisition of a single-slice 2D COSY dataset with an 8 × 8 matrix in 8:32 min on 3 T clinical scanners, which makes it feasible for in vivo studies on human subjects. Here we present the first results obtained on phantoms, human volunteers and patients with brain tumors. The patient data obtained by us represent the first clinical demonstration of a feasible and robust multivoxel 2D COSY. Compared to the 2D J-resolved method, 2D COSY and TOCSY provide increased spectral dispersion which scales up with increasing main magnetic field strength and may have improved ability to unambiguously identify overlapping metabolites. It is expected that the new developments presented in this work will facilitate in vivo application of 2D chemical shift correlation MRS in basic science and clinical studies.
Collapse
Affiliation(s)
- Ovidiu C Andronesi
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA.
| | | | | | | |
Collapse
|
322
|
Busch MG, Finsterbusch J. Eliminating side excitations in PROPELLER-based 2D-selective RF excitations. Magn Reson Med 2012; 68:1383-9. [DOI: 10.1002/mrm.24172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 12/07/2011] [Accepted: 12/23/2011] [Indexed: 11/12/2022]
|
323
|
Verma G, Lipnick S, Ramadan S, Nagarajan R, Thomas MA. Implementation of multi-echo-based correlated spectroscopic imaging and pilot findings in human brain and calf muscle. J Magn Reson Imaging 2012; 34:262-9. [PMID: 21780221 DOI: 10.1002/jmri.22624] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To implement a spatially encoded correlated spectroscopic imaging (COSI) sequence on 3 Tesla (T) MRI/MR spectroscopy scanners incorporating four echoes to collect four phase-encoded acquisitions per repetition time (TR), and to evaluate the performance and reliability of this four-dimensional (4D) multi-echo COSI (ME-COSI) sequence in brain and calf muscle. MATERIALS AND METHODS Typical scan parameters for the 4D datasets were as follows: repetition time = 1500 ms, 2000 Hz bandwidth, 8 × 8 spatial encoding, one average, 64 Δt(1) increments and the scan duration was 25 min. The performance and test-retest reliability of ME-COSI were evaluated with phantoms and in the occipitoparietal brain tissues and calf of six healthy volunteers (mean age = 32 years old). RESULTS Regional differences in concentrations of lipids, creatine (Cr), choline (Ch), and carnosine (Car) were observed between spectra from voxels located in tibial marrow, tibialis anterior, and soleus muscle. Diagonal and cross-peak resonances were identified from several brain metabolites including N-acetyl aspartate (NAA), Ch, Cr, lactate (Lac), aspartate (Asp), glutathione (GSH), and glutamine\glutamate (Glx). Coefficients of variation (CV) in metabolite ratios across repeated measurements were <15% for diagonal and <25% for cross-peaks observed in vivo. CONCLUSION The ME-COSI sequence reliably acquired spatially resolved 2D Correlated Spectroscopy (COSY) spectra demonstrating the feasibility of differentiating spatial variation of metabolites in different tissues. Multi-echo acquisition shortens scan duration to clinically feasible times.
Collapse
Affiliation(s)
- Gaurav Verma
- Department of Bioengineering, University of California, Los Angeles, California 90095-1721, USA
| | | | | | | | | |
Collapse
|
324
|
Andronesi OC, Kim GS, Gerstner E, Batchelor T, Tzika AA, Fantin VR, Vander Heiden MG, Sorensen AG. Detection of 2-hydroxyglutarate in IDH-mutated glioma patients by in vivo spectral-editing and 2D correlation magnetic resonance spectroscopy. Sci Transl Med 2012; 4:116ra4. [PMID: 22238332 PMCID: PMC3720836 DOI: 10.1126/scitranslmed.3002693] [Citation(s) in RCA: 303] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Mutations in the gene isocitrate dehydrogenase 1 (IDH1) are present in up to 86% of grade II and III gliomas and secondary glioblastoma. Arginine 132 (R132) mutations in the enzyme IDH1 result in excess production of the metabolite 2-hydroxyglutarate (2HG), which could be used as a biomarker for this subset of gliomas. Here, we use optimized in vivo spectral-editing and two-dimensional (2D) correlation magnetic resonance spectroscopy (MRS) methods to unambiguously detect 2HG noninvasively in glioma patients with IDH1 mutations. By comparison, fitting of conventional 1D MR spectra can provide false-positive readouts owing to spectral overlap of 2HG and chemically similar brain metabolites, such as glutamate and glutamine. 2HG was also detected using 2D high-resolution magic angle spinning MRS performed ex vivo on a separate set of glioma biopsy samples. 2HG detection by in vivo or ex vivo MRS enabled detailed molecular characterization of a clinically important subset of human gliomas. This has implications for diagnosis as well as monitoring of treatments targeting mutated IDH1.
Collapse
Affiliation(s)
- Ovidiu C Andronesi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
| | | | | | | | | | | | | | | |
Collapse
|
325
|
2D MR Spectroscopy Combined with Prior-Knowledge Fitting Is Sensitive to HCV-Associated Cerebral Metabolic Abnormalities. Int J Hepatol 2012; 2012:179365. [PMID: 22844602 PMCID: PMC3403451 DOI: 10.1155/2012/179365] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Revised: 05/05/2012] [Accepted: 05/19/2012] [Indexed: 11/18/2022] Open
Abstract
There is an evidence of neurocognitive dysfunction even in the absence of advanced liver disease in chronic hepatitis C virus (HCV) infection. Brain metabolism has been investigated non-invasively using one-dimensional (1D) in vivo Magnetic Resonance Spectroscopy (MRS) over three decades. Even though highly concentrated cerebral metabolites (N-acetylaspartate, creatine, choline, glutamate/glutamine, myo-inositol) have been detected using MRS, other metabolites at low concentrations (~1-3 mM or less) including glutathione, aspartate and GABA are quite difficult to observe using 1D MRS. In order to resolve overlapping resonances from a number of metabolites, a remedy is to add a second spectral dimension to the existing 1D MRS. Localized two-dimensional correlated spectroscopy (L-COSY) has been developed over the last decade to enhance the spectral dispersion by using the second spectral dimension. We have evaluated this L-COSY technique in the frontal white/gray matter regions of 14 HCV+ (mean age of 56.2 years) and 14 HCV- (mean age of 46.6 years) subjects. Our preliminary results showed significantly increased myo-inositol and glutathione in the HCV+ compared to the HCV- subjects. Hence, glutathione and myo-inositol should be considered along with other metabolites as important markers of inflammation.
Collapse
|
326
|
Dalitz F, Cudaj M, Maiwald M, Guthausen G. Process and reaction monitoring by low-field NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2012; 60:52-70. [PMID: 22293399 DOI: 10.1016/j.pnmrs.2011.11.003] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 11/29/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Franz Dalitz
- Institute of Mechanical Process Engineering and Mechanics, SRG10-2, KIT, Adenauerring 20 b, 76131 Karlsruhe, Germany
| | | | | | | |
Collapse
|
327
|
Gowda GAN, Shanaiah N, Raftery D. Isotope enhanced approaches in metabolomics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 992:147-64. [PMID: 23076583 DOI: 10.1007/978-94-007-4954-2_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The rapidly growing area of "metabolomics," in which a large number of metabolites from body fluids, cells or tissue are detected quantitatively, in a single step, promises immense potential for a number of disciplines including early disease diagnosis, therapy monitoring, systems biology, drug discovery and nutritional science. Because of its ability to detect a large number of metabolites in intact biological samples reproducibly and quantitatively, nuclear magnetic resonance (NMR) spectroscopy has emerged as one of the most powerful analytical techniques in metabolomics. NMR spectroscopy of biological samples with isotope labeling of metabolites using nuclei such as (2)H, (13)C, (15)N and (31)P, either in vivo or ex vivo, has dramatically improved our ability to identify low concentrated metabolites and trace important metabolic pathways. Considering the somewhat limited sensitivity and high complexity of NMR spectra of biological samples, efforts have been made to increase sensitivity and selectivity through isotope labeling methods, which pave novel avenues to unravel biological complexity and understand cellular functions in health and various disease conditions. This chapter describes current developments in isotope labeling of metabolites in vivo as well as ex vivo, and their potential metabolomics applications.
Collapse
Affiliation(s)
- G A Nagana Gowda
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109, USA.
| | | | | |
Collapse
|
328
|
Andronesi OC, Gagoski BA, Sorensen AG. Neurologic 3D MR spectroscopic imaging with low-power adiabatic pulses and fast spiral acquisition. Radiology 2011; 262:647-61. [PMID: 22187628 DOI: 10.1148/radiol.11110277] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE To improve clinical three-dimensional (3D) MR spectroscopic imaging with more accurate localization and faster acquisition schemes. MATERIALS AND METHODS Institutional review board approval and patient informed consent were obtained. Data were acquired with a 3-T MR imager and a 32-channel head coil in phantoms, five healthy volunteers, and five patients with glioblastoma. Excitation was performed with localized adiabatic spin-echo refocusing (LASER) by using adiabatic gradient-offset independent adiabaticity wideband uniform rate and smooth truncation (GOIA-W[16,4]) pulses with 3.5-msec duration, 20-kHz bandwidth, 0.81-kHz amplitude, and 45-msec echo time. Interleaved constant-density spirals simultaneously encoded one frequency and two spatial dimensions. Conventional phase encoding (PE) (1-cm3 voxels) was performed after LASER excitation and was the reference standard. Spectra acquired with spiral encoding at similar and higher spatial resolution and with shorter imaging time were compared with those acquired with PE. Metabolite levels were fitted with software, and Bland-Altman analysis was performed. RESULTS Clinical 3D MR spectroscopic images were acquired four times faster with spiral protocols than with the elliptical PE protocol at low spatial resolution (1 cm3). Higher-spatial-resolution images (0.39 cm3) were acquired twice as fast with spiral protocols compared with the low-spatial-resolution elliptical PE protocol. A minimum signal-to-noise ratio (SNR) of 5 was obtained with spiral protocols under these conditions and was considered clinically adequate to reliably distinguish metabolites from noise. The apparent SNR loss was not linear with decreasing voxel sizes because of longer local T2* times. Improvement of spectral line width from 4.8 Hz to 3.5 Hz was observed at high spatial resolution. The Bland-Altman agreement between spiral and PE data is characterized by narrow 95% confidence intervals for their differences (0.12, 0.18 of their means). GOIA-W(16,4) pulses minimize chemical-shift displacement error to 2.1%, reduce nonuniformity of excitation to 5%, and eliminate the need for outer volume suppression. CONCLUSION The proposed adiabatic spiral 3D MR spectroscopic imaging sequence can be performed in a standard clinical MR environment. Improvements in image quality and imaging time could enable more routine acquisition of spectroscopic data than is possible with current pulse sequences.
Collapse
Affiliation(s)
- Ovidiu C Andronesi
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 13th St, Suite 2301, Boston, MA 02129, USA.
| | | | | |
Collapse
|
329
|
Liu L, Mo H, Wei S, Raftery D. Quantitative analysis of urea in human urine and serum by 1H nuclear magnetic resonance. Analyst 2011; 137:595-600. [PMID: 22179722 DOI: 10.1039/c2an15780b] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A convenient and fast method for quantifying urea in biofluids is demonstrated using NMR analysis and the solvent water signal as a concentration reference. The urea concentration can be accurately determined with errors less than 3% between 1 mM and 50 mM, and less than 2% above 50 mM in urine and serum. The method is promising for various applications with advantages of simplicity, high accuracy, and fast non-destructive detection. With an ability to measure other metabolites simultaneously, this NMR method is also likely to find applications in metabolic profiling and system biology.
Collapse
Affiliation(s)
- Lingyan Liu
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr, West Lafayette, IN 47907, USA
| | | | | | | |
Collapse
|
330
|
Boer VO, Klomp DWJ, Juchem C, Luijten PR, de Graaf RA. Multislice ¹H MRSI of the human brain at 7 T using dynamic B₀ and B₁ shimming. Magn Reson Med 2011; 68:662-70. [PMID: 22162089 DOI: 10.1002/mrm.23288] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 09/26/2011] [Accepted: 10/16/2011] [Indexed: 11/10/2022]
Abstract
Proton MR spectroscopic imaging of the human brain at ultra-high field (≥7 T) is challenging due to increased radio frequency power deposition, increased magnetic field B(0) inhomogeneity, and increased radio frequency magnetic field inhomogeneity. In addition, especially for multislice sequences, these effects directly inhibit the potential gains of higher magnetic field and can even cause a reduction in data quality. However, recent developments in dynamic B(0) magnetic field shimming and dynamic multitransmit radio frequency control allow for new acquisition strategies. Therefore, in this work, slice-by-slice B(0) and B(1) shimming was developed to optimize both B(0) magnetic field homogeneity and nutation angle over a large portion of the brain. Together with a low-power water and lipid suppression sequence and pulse-acquire spectroscopic imaging, a multislice MR spectroscopic imaging sequence is shown to be feasible at 7 T. This now allows for multislice metabolic imaging of the human brain with high sensitivity and high chemical shift resolution at ultra-high field.
Collapse
Affiliation(s)
- Vincent O Boer
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | | | | | | | | |
Collapse
|
331
|
Barding GA, Fukao T, Béni S, Bailey-Serres J, Larive CK. Differential Metabolic Regulation Governed by the Rice SUB1A Gene during Submergence Stress and Identification of Alanylglycine by 1H NMR Spectroscopy. J Proteome Res 2011; 11:320-30. [DOI: 10.1021/pr200919b] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Gregory A. Barding
- Department of Chemistry, University of California −Riverside, California, United States
- Center for Plant Cell Biology, University of California −Riverside, California, United States
| | - Takeshi Fukao
- Center for Plant Cell Biology, University of California −Riverside, California, United States
- Department of Botany and Plant Sciences, University of California −Riverside, California, United States
| | - Szabolcs Béni
- Department of Chemistry, University of California −Riverside, California, United States
- Department of Pharmaceutical Chemistry, Semmelweis University, Budapest, Hungary
| | - Julia Bailey-Serres
- Center for Plant Cell Biology, University of California −Riverside, California, United States
- Department of Botany and Plant Sciences, University of California −Riverside, California, United States
| | - Cynthia K. Larive
- Department of Chemistry, University of California −Riverside, California, United States
- Center for Plant Cell Biology, University of California −Riverside, California, United States
| |
Collapse
|
332
|
McKenzie JS, Donarski JA, Wilson JC, Charlton AJ. Analysis of complex mixtures using high-resolution nuclear magnetic resonance spectroscopy and chemometrics. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 59:336-59. [PMID: 22027342 DOI: 10.1016/j.pnmrs.2011.04.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 04/27/2011] [Indexed: 05/16/2023]
Affiliation(s)
- James S McKenzie
- The Food and Environment Research Agency, Sand Hutton, York YO41 1LZ, United Kingdom
| | | | | | | |
Collapse
|
333
|
Pope WB, Prins RM, Albert Thomas M, Nagarajan R, Yen KE, Bittinger MA, Salamon N, Chou AP, Yong WH, Soto H, Wilson N, Driggers E, Jang HG, Su SM, Schenkein DP, Lai A, Cloughesy TF, Kornblum HI, Wu H, Fantin VR, Liau LM. Non-invasive detection of 2-hydroxyglutarate and other metabolites in IDH1 mutant glioma patients using magnetic resonance spectroscopy. J Neurooncol 2011; 107:197-205. [PMID: 22015945 DOI: 10.1007/s11060-011-0737-8] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 09/26/2011] [Indexed: 10/16/2022]
Abstract
Mutations of the isocitrate dehydrogenase 1 and 2 genes (IDH1 and IDH2) are commonly found in primary brain cancers. We previously reported that a novel enzymatic activity of these mutations results in the production of the putative oncometabolite, R(-)-2-hydroxyglutarate (2-HG). Here we investigated the ability of magnetic resonance spectroscopy (MRS) to detect 2-HG production in order to non-invasively identify patients with IDH1 mutant brain tumors. Patients with intrinsic glial brain tumors (n = 27) underwent structural and spectroscopic magnetic resonance imaging prior to surgery. 2-HG levels from MRS data were quantified using LC-Model software, based upon a simulated spectrum obtained from a GAMMA library added to the existing prior knowledge database. The resected tumors were then analyzed for IDH1 mutational status by genomic DNA sequencing, Ki-67 proliferation index by immunohistochemistry, and concentrations of 2-HG and other metabolites by liquid chromatography-mass spectrometry (LC-MS). MRS detected elevated 2-HG levels in gliomas with IDH1 mutations compared to those with wild-type IDH1 (P = 0.003). The 2-HG levels measured in vivo with MRS were significantly correlated with those measured ex vivo from the corresponding tumor samples using LC-MS (r (2) = 0.56; P = 0.0001). Compared with wild-type tumors, those with IDH1 mutations had elevated choline (P = 0.01) and decreased glutathione (P = 0.03) on MRS. Among the IDH1 mutated gliomas, quantitative 2-HG values were correlated with the Ki-67 proliferation index of the tumors (r ( 2 ) = 0.59; P = 0.026). In conclusion, water-suppressed proton ((1)H) MRS provides a non-invasive measure of 2-HG in gliomas, and may serve as a potential biomarker for patients with IDH1 mutant brain tumors. In addition to 2-HG, alterations in several other metabolites measured by MRS correlate with IDH1 mutation status.
Collapse
Affiliation(s)
- Whitney B Pope
- Department of Radiological Sciences, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
334
|
Furuyama JK, Burns BL, Wilson NE, Thomas MA. Multi-Echo-Based Echo-Planar Spectroscopic Imaging Using a 3T MRI Scanner. MATERIALS (BASEL, SWITZERLAND) 2011; 4:1818-1834. [PMID: 28824110 PMCID: PMC5448876 DOI: 10.3390/ma4101818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 10/06/2011] [Accepted: 10/07/2011] [Indexed: 11/16/2022]
Abstract
The use of spin-echoes has been employed in an Echo-Planar Spectroscopic Imaging (EPSI) sequence to collect multiple phase encoded lines within a single TR in a Multi-Echo-based Echo-Planar Spectroscopic Imaging technique (MEEPSI). Despite the T₂ dependence on the amplitude of the spin-echoes, the Full Width at Half Maximum (FWHM) of the derived multi-echo Point Spread Function (PSF) is shown to decrease, indicating an improved overall spatial resolution without requiring any additional scan time. The improved spatial resolution is demonstrated in the one-dimensional (1D) spatial profiles of the N-Acetyl Aspartate (NAA) singlet along the phase encode dimension in a gray matter phantom. Although the improved spatial resolution comes at the expense of spectral resolution, it is shown in vivo that peak broadening due to T₂* decay is more significant than the loss of resolution from using spin-echoes and therefore does not affect the ability to quantify metabolites using the LCModel fitting algorithm.
Collapse
Affiliation(s)
- Jon K Furuyama
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA
| | - Brian L Burns
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA
- Medical Imaging Informatics (MII) Lab, University of California, Los Angeles, CA 90095, USA
| | - Neil E Wilson
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA
| | - M Albert Thomas
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA.
| |
Collapse
|
335
|
Furuyama JK, Wilson NE, Thomas MA. Spectroscopic imaging using concentrically circular echo-planar trajectories in vivo. Magn Reson Med 2011; 67:1515-22. [DOI: 10.1002/mrm.23184] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 07/05/2011] [Accepted: 08/01/2011] [Indexed: 11/07/2022]
|
336
|
Ramadan S, Mountford CE. Adiabatic localized correlation spectroscopy (AL-COSY): application in muscle and brain. J Magn Reson Imaging 2011; 33:1447-55. [PMID: 21591015 DOI: 10.1002/jmri.22555] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To describe an enhanced version of a localized correlation spectroscopy (L-COSY) by introducing adiabatic radiofrequency (RF) pulses for localization in two dimensions. Adiabatic pulses will improve slice selection profile and reduce chemical shift artifacts. Optimized Mao and adiabatic hyperbolic secant pulses are tested in vivo. MATERIALS AND METHODS Region of interest is localized by a 90° nonselective adiabatic RF pulse followed by two pairs of adiabatic RF pulses and a terminal 90° RF sinc pulse. Slice profiles for both refocusing pulses and chemical shift artifacts are measured in a water-oil phantom for L-COSY and AL-COSY. In vivo results of both COSY sequences are shown from muscle and brain on a 3 Tesla (T) scanner. RESULTS Chemical shift artifacts were reduced with AL-COSY compared with L-COSY. Slice profiles of adiabatic pulses were found to be sharper and more symmetrical than those of traditional Mao pulses. One-dimensional (1D) phantom studies showed longer T2 values using AL-COSY sequence. Comparison of 2D spectra obtained revealed spectroscopic peak volume improvements in AL-COSY and less residual water. In vivo 1D comparison showed more inphase and sharper peaks in AL-COSY spectrum. CONCLUSION The AL-COSY sequence is an improved sequence due to sharper slice selection profiles, reduction of chemical shift artifacts, peak volume improvements in 2D techniques, and less J-modulation.
Collapse
Affiliation(s)
- Saadallah Ramadan
- Center for Clinical Spectroscopy, Department of Radiology, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
| | | |
Collapse
|
337
|
Vilén EM, Klinger M, Sandström C. Application of diffusion-edited NMR spectroscopy for selective suppression of water signal in the determination of monomer composition in alginates. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011; 49:584-591. [PMID: 21815213 DOI: 10.1002/mrc.2789] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/30/2011] [Accepted: 06/01/2011] [Indexed: 05/31/2023]
Abstract
Alginate is a linear copolymer of 1-4 linked β-D-mannuronic acid (M) and 1-4 linked α-L-guluronic acid (G). The physical properties of these polysaccharides such as gel properties and viscosity are largely correlated to the monomer composition (M/G ratio), the sequence of the polymer and the molecular weight. Determination of the M/G ratio is therefore important and NMR spectroscopy is among the most common methods used to accurately obtain this ratio. Instead of using time consuming, possibly sample altering, acid hydrolysis to reduce the viscosity of the alginate sample prior to analysis, samples of low concentrations can be used. However, this results in a water peak in the NMR spectrum that is several orders of magnitude larger than the alginate signals and water suppression is required. In this article, a diffusion-edited NMR experiment that suppresses the water peak while retaining the signals of interest has been used to enable correct M/G ratio determination. This approach exploits the difference in translational diffusion between the larger alginate molecules and the smaller water molecules. Using this method, the monomer composition of 20 different alginate powders was determined. The diffusion parameters were optimized to allow measurement for samples covering a large range of M/G ratios and viscosities. Thus, such method should be useful for analyzing large numbers of unknown alginate samples using, for example, automation procedures.
Collapse
Affiliation(s)
- Eric Morssing Vilén
- Department of Chemistry, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
| | | | | |
Collapse
|
338
|
Filippi CG, Pace T, Perkins TG, Murdoch JB, Andrews T. Proton MR spectroscopy in a 1T open MR imaging system. AJNR Am J Neuroradiol 2011; 32:E156-9. [PMID: 21163878 DOI: 10.3174/ajnr.a2305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
(1)H-MR spectroscopy is an established noninvasive MR imaging technique that can be helpful in the diagnosis of brain lesions and in treatment planning. Claustrophobia and body habitus preclude some patients from routine MR imaging in a closed-bore system. The development of (1)H-MR spectroscopy for use in an open MR imaging system would enable a more complete characterization of brain lesions in these patients.
Collapse
Affiliation(s)
- C G Filippi
- Fletcher Allen Health Care, Burlington, Vermont 05401, USA.
| | | | | | | | | |
Collapse
|
339
|
Sarma MK, Huda A, Nagarajan R, Hinkin CH, Wilson N, Gupta RK, Frias-Martinez E, Sayre J, Guze B, Han SH, Thomas MA. Multi-dimensional MR spectroscopy: towards a better understanding of hepatic encephalopathy. Metab Brain Dis 2011; 26:173-84. [PMID: 21698453 PMCID: PMC3181227 DOI: 10.1007/s11011-011-9250-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 06/06/2011] [Indexed: 12/14/2022]
Abstract
Hepatic encephalopathy (HE) is normally diagnosed by neuropsychological (NP) tests. The goals of this study were to quantify cerebral metabolites, separate glutamate (Glu) from glutamine (Gln) in patients with minimal hepatic encephalopathy (MHE) as well as healthy subjects using the prior-knowledge fitting (ProFit) algorithm on data acquired by two-dimensional (2D) localized correlated spectroscopy (L-COSY) on two different MR scanners, and to correlate the metabolite changes with neuropsychological (NP) tests. We studied 14 MHE patients and 18 healthy controls using a GE 1.5 T Signa MR scanner. Another group of 16 MHE patients and 18 healthy controls were studied using a Siemens 1.5 T Avanto MR scanner. The following parameters were used for L-COSY: TR/TE = 2 s/30 ms, 3 × 3 × 3 cm(3) voxel size, 96 Δt(1) increments with 8 averages per Δt(1). Using the ProFit algorithm, we were able to differentiate Gln from Glu on the GE 1.5 T data in the medial frontal white/gray matter. The ratios of myo-inositol (mI), Glu, total choline, scyllo-inositol (sI), phosphoethanolamine (PE), and total N-acetyl aspartate (NAA) showed statistically significant decline in HE patients compared to healthy controls, while the ratio of Gln was significantly increased. Similar trend was seen in the ProFit quantified Siemens 1.5 T data in the frontal and occipito-parietal white/gray regions. Among the NP domain scores, motor function, cognitive speed, executive function and the global scores showed significant differences. Excellent correlations between various NP domains and metabolite ratios were also observed. ProFit based cerebral metabolite quantitation enhances the understanding and basis of the current hypothesis of MHE.
Collapse
Affiliation(s)
- Manoj K. Sarma
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Amir Huda
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA
- Department of Physics, California State University, Fresno, California, USA
| | - Rajakumar Nagarajan
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Charles H. Hinkin
- Department of Psychiatry, David Geffen School of Medicine, University of California, Los Angeles, California, USA
- VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Neil Wilson
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Rakesh K. Gupta
- Department of Radiology, Sanjay Gandhi Post-Graduate Institute of Medical Sciences, Lucknow, India
| | - Enrique Frias-Martinez
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - James Sayre
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Barry Guze
- Department of Psychiatry, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Steven-Huy Han
- Department of Hepatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - M. Albert Thomas
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA
- Department of Psychiatry, David Geffen School of Medicine, University of California, Los Angeles, California, USA
- Correspondence: M. Albert Thomas PhD, Department of Radiological Sciences, David Geffen School of Medicine at UCLA, CHS BL 428, 10833 Le Conte Avenue, Los Angeles, CA 90095-1721, USA, Tel: +1-310-206-4191, Fax: +1-310-825-5837,
| |
Collapse
|
340
|
Klomp DWJ, Renema WKJ. Spectroscopic imaging of the mouse brain. Methods Mol Biol 2011; 771:337-51. [PMID: 21874487 DOI: 10.1007/978-1-61779-219-9_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Magnetic resonance spectroscopic imaging (MRSI) of the mouse brain reveals a wealth of metabolic information, not only from a single region of interest (single voxel), but spatially mapped over potentially the entire brain. However, MRSI requires challenging methods before the data can be obtained accurately. When applied in vivo, MRSI is generally combined with volume-selective spin perturbation to exclude artifact originating from outside the volume of interest. To obtain good magnetic field (B (0)) uniformity at this volume, accurate B (0) shimming is required. Finally, the immensely large signals originating from water spins need to be suppressed to prevent sidebands that contaminate the spectra, or even saturate the dynamic range of the MR receiver. This chapter describes solutions for these challenges and ends with a rationale between single-voxel MRS versus MRSI.
Collapse
Affiliation(s)
- Dennis W J Klomp
- Department of Radiology, University Medical Center, 3584 CX, Utrecht, The Netherlands.
| | | |
Collapse
|
341
|
Rial B, Robson MD, Neubauer S, Schneider JE. Rapid quantification of myocardial lipid content in humans using single breath-hold 1H MRS at 3 Tesla. Magn Reson Med 2011; 66:619-24. [PMID: 21721038 PMCID: PMC3427889 DOI: 10.1002/mrm.23011] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 04/25/2011] [Accepted: 04/28/2011] [Indexed: 01/03/2023]
Abstract
A rapid, proton magnetic resonance spectroscopy method to evaluate human myocardial lipid levels in a single breath-hold at 3 T using a commercial whole-body system is presented. During a 10 s breath-hold, water unsuppressed and suppressed spectra were acquired by two phased array coils using a short-echo time spectroscopic stimulated echo (STEAM) sequence electrocardiogram-triggered to mid-diastole. Lipid-to-water ratios were obtained in the septum of 15 healthy volunteers, (0.46 ± 0.19)%. These results agreed well with ratios obtained from averaged spectra acquired in seven multiple breath-holds, (0.45 ± 0.20)%, providing increased signal-to-noise ratio but requiring longer acquisition times. Excellent correlation was found between the two methods (r = 0.94, P < 0.05). Reproducibility of 1H MRS for measuring myocardial lipid levels in a short breath-hold was acceptable in five repeated measurements within the same subject (coefficient of variation = 19%). Thus, single breath-hold proton spectroscopy allows reliable and quick quantification of myocardial lipids at 3 T. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.
Collapse
Affiliation(s)
- Belen Rial
- Department of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom
| | | | | | | |
Collapse
|
342
|
Snyder J, Haas M, Hennig J, Zaitsev M. Selective excitation of two-dimensional arbitrarily shaped voxels with parallel excitation in spectroscopy. Magn Reson Med 2011; 67:300-9. [DOI: 10.1002/mrm.23018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 04/29/2011] [Accepted: 05/01/2011] [Indexed: 11/11/2022]
|
343
|
Abe T. Fast fat suppression RF pulse train with insensitivity to B1 inhomogeneity for body imaging. Magn Reson Med 2011; 67:464-9. [PMID: 21633968 DOI: 10.1002/mrm.23015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 04/24/2011] [Accepted: 04/29/2011] [Indexed: 11/09/2022]
Abstract
In higher-field magnetic resonance imaging scanners, a spectrally selective fat saturation radiofrequency (RF) pulse does not work well because B(1) inhomogeneity increases. An adiabatic 180° pulse is used to improve nonuniform fat suppression, but requires inversion recovery time. Therefore, a new RF pulse that achieves flip angles near 90° and is B(1) insensitive has been developed. The pulse consists of three sinc-shaped RF pulses with different flip angles and with different time intervals between each RF pulse. Using the Bloch equations, we analyzed the optimal combination of flip angles. Experimental results demonstrated that M(z) was maintained at less than 0.05 M(0) for a B(1) inhomogeneity of ±35%. The optimal net flip angles was adjusted to 95° by varying the time interval between RF pulses. The pulse duration was 77 ms, which is less than half of the 170-ms inversion recovery time required for the adiabatic pulse. We demonstrated excellent fat suppression for body imaging.
Collapse
Affiliation(s)
- Takayuki Abe
- MRI Division, Hitachi Medical Corporation, Kashiwa, Chiba, Japan.
| |
Collapse
|
344
|
Buijs M, Vossen JA, Geschwind JFH, Salibi N, Pan L, Ventura VP, Liapi E, Lee KH, Kamel IR. Quantitative proton MR spectroscopy as a biomarker of tumor necrosis in the rabbit VX2 liver tumor. J Vasc Interv Radiol 2011; 22:1175-80. [PMID: 21620723 DOI: 10.1016/j.jvir.2011.03.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 03/16/2011] [Accepted: 03/22/2011] [Indexed: 12/13/2022] Open
Abstract
PURPOSE To compare metabolic magnetic resonance (MR) imaging findings (ie, quantification of tumor choline concentration) with percentage of necrosis on pathologic examination in rabbits bearing VX2 liver tumors. MATERIALS AND METHODS VX2 tumors were implanted in the livers of 16 rabbits. MR imaging was performed with a 1.5-T MR scanner and extremity coil, and a hydrogen-1 ((1)H) proton MR spectroscopy ((1)H MRS) imaging protocol was used. Rabbits were euthanized immediately after imaging, and the tumor was harvested and sliced at 4-mm intervals in the axial plane. Choline concentration was calculated and was compared with the percentage of tumor necrosis on pathologic examination. RESULTS Mean tumor size at pathologic examination was 16 mm (range, 12-22 mm). Mean percentage of necrosis at pathologic examination was 22% (range, 4%-44%). Choline concentration showed a relatively high inverse correlation with percentage of necrosis on pathologic examination, with an r value of 0.78 (P < .002). CONCLUSIONS Choline concentration showed a relatively high inverse correlation with tumor necrosis on pathologic examination. Therefore, (1)H MRS may be useful to assess tumor necrosis.
Collapse
Affiliation(s)
- Manon Buijs
- Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, 600 N Wolfe St, Room 100, Baltimore, MD 21287, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
345
|
Kim H, Catana C, Ratai EM, Andronesi OC, Jennings DL, Batchelor TT, Jain RK, Sorensen AG. Serial magnetic resonance spectroscopy reveals a direct metabolic effect of cediranib in glioblastoma. Cancer Res 2011; 71:3745-52. [PMID: 21507932 DOI: 10.1158/0008-5472.can-10-2991] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Proton magnetic resonance spectroscopy is increasingly used in clinical studies of brain tumor to provide information about tissue metabolic profiles. In this study, we evaluated changes in the levels of metabolites predominant in recurrent glioblastoma multiforme (rGBM) to characterize the response of rGBM to antiangiogenic therapy. We examined 31 rGBM patients treated with daily doses of cediranib, acquiring serial chemical shift imaging data at specific time points during the treatment regimen. We defined spectra from three regions of interest (ROI)--enhancing tumor (ET), peritumoral tissue, and normal tissue on the contralateral side (cNT)--in post-contrast T1-weighted images, and normalized the concentrations of N-acetylaspartate (NAA) and choline (Cho) in each ROI to the concentration of creatine in cNT (norCre). We analyzed the ratios of these normalized metabolites (i.e., NAA/Cho, NAA/norCre, and Cho/norCre) by averaging all patients and categorizing two different survival groups. Relative to pretreatment values, NAA/Cho in ET was unchanged through day 28. However, after day 28, NAA/Cho significantly increased in relation to a significant increase in NAA/norCre and a decrease in Cho/norCre; interestingly, the observed trend was reversed after day 56, consistent with the clinical course of GBM recurrence. Notably, receiver operating characteristic analysis indicated that NAA/Cho in tumor shows a high prediction to 6-month overall survival. These metabolic changes in these rGBM patients strongly suggest a direct metabolic effect of cediranib and might also reflect an antitumor response to antiangiogenic treatment during the first 2 months of treatment. Further study is needed to confirm these findings.
Collapse
Affiliation(s)
- Heisoog Kim
- Massachusetts Institute of Technology, Department of Nuclear Science and Engineering-Health Science and Technology, Cambridge, Massachusetts, USA.
| | | | | | | | | | | | | | | |
Collapse
|
346
|
Gröger A, Chadzynski G, Godau J, Berg D, Klose U. Three-dimensional magnetic resonance spectroscopic imaging in the substantia nigra of healthy controls and patients with Parkinson's disease. Eur Radiol 2011; 21:1962-9. [PMID: 21484351 DOI: 10.1007/s00330-011-2123-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/04/2011] [Accepted: 02/24/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVES To investigate the substantia nigra in patients with Parkinson's disease three-dimensional magnetic resonance spectroscopic imaging with high spatial resolution at 3 Tesla was performed. Regional variations of spectroscopic data between the rostral and caudal regions of the substantia nigra as well as the midbrain tegmentum areas were evaluated in healthy controls and patients with Parkinson's disease. METHODS Nine patients with Parkinson's disease and eight age- and gender-matched healthy controls were included in this study. Data were acquired by using three-dimensional magnetic resonance spectroscopic imaging measurements. The ratios between rostral and caudal voxels of the substantia nigra as well as the midbrain tegmentum areas were calculated for the main-metabolites N-acetyl aspartate, creatine, choline, and myo-inositol. Additionally, the metabolite/creatine ratios were calculated. RESULTS In all subjects spectra of acceptable quality could be obtained with a nominal voxel size of 0.252 ml. The calculated rostral-to-caudal ratios of the metabolites as well as of the metabolite/creatine ratios showed with exception of choline/creatine ratio significant differences between healthy controls and patients with Parkinson's disease. CONCLUSIONS The findings from this study indicate that regional variations in N-acetyl aspartate/creatine ratios in the regions of the substantia nigra may differentiate patients with Parkinson's disease and healthy controls.
Collapse
Affiliation(s)
- Adriane Gröger
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Disease (DZNE), University of Tuebingen, Tuebingen, Germany.
| | | | | | | | | |
Collapse
|
347
|
Busch MG, Finsterbusch J. Spatially 2D-selective RF excitations using the PROPELLER trajectory: Basic principles and application to MR spectroscopy of irregularly shaped single voxel. Magn Reson Med 2011; 66:1218-25. [DOI: 10.1002/mrm.22903] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 02/02/2011] [Accepted: 02/10/2011] [Indexed: 11/09/2022]
|
348
|
Xu Q, Vu H, Liu L, Wang TC, Schaefer WH. Metabolic profiles show specific mitochondrial toxicities in vitro in myotube cells. JOURNAL OF BIOMOLECULAR NMR 2011; 49:207-219. [PMID: 21359514 DOI: 10.1007/s10858-011-9482-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 12/10/2010] [Indexed: 05/30/2023]
Abstract
Mitochondrial toxicity has been a serious concern, not only in preclinical drug development but also in clinical trials. In mitochondria, there are several distinct metabolic processes including fatty acid β-oxidation, the tricarboxylic acid (TCA) cycle, and oxidative phosphorylation (OXPHOS), and each process contains discrete but often intimately linked steps. Interruption in any one of those steps can cause mitochondrial dysfunction. Detection of inhibition to OXPHOS can be complicated in vivo because intermediate endogenous metabolites can be recycled in situ or circulated systemically for metabolism in other organs or tissues. Commonly used assays for evaluating mitochondrial function are often applied to ex vivo or in vitro samples; they include various enzymatic or protein assays, as well as functional assays such as measurement of oxygen consumption rate, membrane potential, or acidification rates. Metabolomics provides quantitative profiles of overall metabolic changes that can aid in the unraveling of explicit biochemical details of mitochondrial inhibition while providing a holistic view and heuristic understanding of cellular bioenergetics. In this paper, we showed the application of quantitative NMR metabolomics to in vitro myotube cells treated with mitochondrial toxicants, rotenone and antimycin A. The close coupling of the TCA cycle to the electron transfer chain (ETC) in OXPHOS enables specific diagnoses of inhibition to ETC complexes by discrete biochemical changes in the TCA cycle.
Collapse
Affiliation(s)
- Qiuwei Xu
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486, USA.
| | | | | | | | | |
Collapse
|
349
|
NMR techniques in biomedical and pharmaceutical analysis. J Pharm Biomed Anal 2011; 55:1-15. [DOI: 10.1016/j.jpba.2010.12.023] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 12/12/2010] [Accepted: 12/15/2010] [Indexed: 01/04/2023]
|
350
|
Choi C, Ganji SK, DeBerardinis RJ, Dimitrov IE, Pascual JM, Bachoo R, Mickey BE, Malloy CR, Maher EA. Measurement of glycine in the human brain in vivo by 1H-MRS at 3 T: application in brain tumors. Magn Reson Med 2011; 66:609-18. [PMID: 21394775 DOI: 10.1002/mrm.22857] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 12/21/2010] [Accepted: 01/10/2011] [Indexed: 01/27/2023]
Abstract
Glycine is a key metabolic intermediate required for the synthesis of proteins, nucleic acids, and other molecules, and its detection in cancer could, therefore, provide biologically relevant information about the growth of the tumor. Here, we report measurement of glycine in human brain and gliomas by an optimized point-resolved spectroscopy sequence at 3 T. Echo time dependence of the major obstacle, myo-inositol (mI) multiplet, was investigated with numerical simulations, incorporating the 3D volume localization. The simulations indicated that a subecho pair (TE(1) , TE(2) ) = (60, 100) ms permits detection of both glycine and mI with optimum selectivity. In vivo validation of the optimized point-resolved spectroscopy was conducted on the right parietal cortex of five healthy volunteers. Metabolite signals estimated from LC Model were normalized with respect to the brain water signal, and the concentrations were evaluated assuming the total creatine concentration at 8 mM. The glycine concentration was estimated as 0.6 ± 0.1 mM (mean ± SD, n = 5), with a mean Cramér-Rao lower bound of 9 ± 1%. The point-resolved spectroscopy sequence was applied to measure the glycine levels in patients with glioblastoma multiforme. Metabolite concentrations were obtained using the water signal from the tumor mass. The study revealed that a subset of human gliomas contains glycine levels elevated 1.5-8 fold relative to normal.
Collapse
Affiliation(s)
- Changho Choi
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|