Reference deconvolution: A simple and effective method for resolution enhancement in nuclear magnetic resonance spectroscopy

Metz, Kenneth R.; Lam, M. M.; Webb, Andrew

doi:10.1002/(sici)1099-0534(2000)12:1<21::aid-cmr4>3.3.co;2-i

Cited by 22 publications

(28 citation statements)

References 37 publications

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“…By analogy to one-dimensional reference deconvolution methods [42] and to image restoration in optical microscopy [43], we have estimated the PSF using the three-dimensional line shape of a well-resolved and isolated resonance (T92, Figure 1A) and used this in deconvolution algorithms to restore the original, unbroadened spectrum. A variety of deconvolution methods have been described, such as the Wiener filter [44] or maximum entropy methods [45]; in this instance we have found the iterative Richardson-Lucy algorithm [37] to be particularly effective.…”

Section: Resultsmentioning

confidence: 99%

In-Cell NMR Characterization of the Secondary Structure Populations of a Disordered Conformation of α-Synuclein within E. coli Cells

et al. 2013

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α-Synuclein is a small protein strongly implicated in the pathogenesis of Parkinson’s disease and related neurodegenerative disorders. We report here the use of in-cell NMR spectroscopy to observe directly the structure and dynamics of this protein within E. coli cells. To improve the accuracy in the measurement of backbone chemical shifts within crowded in-cell NMR spectra, we have developed a deconvolution method to reduce inhomogeneous line broadening within cellular samples. The resulting chemical shift values were then used to evaluate the distribution of secondary structure populations which, in the absence of stable tertiary contacts, are a most effective way to describe the conformational fluctuations of disordered proteins. The results indicate that, at least within the bacterial cytosol, α-synuclein populates a highly dynamic state that, despite the highly crowded environment, has the same characteristics as the disordered monomeric form observed in aqueous solution.

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Section: Resultsmentioning

confidence: 99%

In-Cell NMR Characterization of the Secondary Structure Populations of a Disordered Conformation of α-Synuclein within E. coli Cells

et al. 2013

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“…The relative area under the overlapping peak was analyzed using the Gaussian/Lorentzian deconvolution technique [27,28]. …”

Section: Methodsmentioning

confidence: 99%

Efficient 1H-NMR Quantitation and Investigation of N-Acetyl-D-glucosamine (GlcNAc) and N,N'-Diacetylchitobiose (GlcNAc)2 from Chitin

Liu

et al. 2011

IJMS

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A quantitative determination method of N-acetyl-d-glucosamine (GlcNAc) and N,N′-diacetylchitobiose (GlcNAc)2 is proposed using a proton nuclear magnetic resonance experiment. N-acetyl groups of GlcNAc and (GlcNAc)2 are chosen as target signals, and the deconvolution technique is used to determine the concentration of the corresponding compound. Compared to the HPLC method, 1H-NMR spectroscopy is simple and fast. The method can be used for the analysis of chitin hydrolyzed products with real-time analysis, and for quantifying the content of products using internal standards without calibration curves. This method can be used to quickly evaluate chitinase activity. The temperature dependence of 1H-NMR spectra (VT-NMR) is studied to monitor the chemical shift variation of acetyl peak. The acetyl groups of products are involved in intramolecular H-bonding with the OH group on anomeric sites. The rotation of the acetyl group is closely related to the intramolecular hydrogen bonding pattern, as suggested by the theoretical data (molecular modeling).

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“…In contrast, the T 2 relaxation time of the reconstructed lineshape signal is virtually infinite, and the lineshape signal decays slower than do any metabolite signals, subject only to the errors in field mapping caused by noise in the MR images. Therefore, noise amplification and spike artifacts can be smaller when using SPREAD than when using deconvolution with water signal as a reference (24). (3) Measurement of the internal water signal typically requires acquisition of a water MRSI dataset in addition to the metabolite data, thereby doubling total MRSI scan time, an often impractical requirement in most human imaging protocols.…”

Section: Discussionmentioning

confidence: 99%

“…To eliminate the spikes near zero-crossing points, we replaced the values of the denominator in Eq. [10] by 1 when the ratio of s v / L v larger than 8 (24). We note that alternative methods, such as QUECC (30), can also be used to suppress the spikes, which is specially useful for short TE MRSI data.…”

Section: Methodsmentioning

confidence: 99%

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Spectral resolution amelioration by deconvolution (SPREAD) in MR spectroscopic imaging

Dong

Peterson

2009

Magnetic Resonance Imaging

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Purpose: To develop, implement, and evaluate a novel postprocessing method for enhancing the spectral resolution of in vivo MR spectroscopic imaging (MRSI) data. Materials and Methods:Magnetic field inhomogeneity across the imaging volume was determined by acquiring MRI datasets with two differing echo times. The lineshapes of the MRSI spectra were derived from these field maps by simulating an MRSI scan of a virtual sample whose resonance frequencies varied according to the observed variations in the magnetic field. By deconvolving the lineshapes from the measured MRSI spectra, the linebroadening effects of the field inhomogeneities were reduced significantly.Results: Both phantom and in vivo proton MRSI spectra exhibited significantly enhanced spectral resolutions and improved spectral lineshapes following application of our method. Quantitative studies on a phantom show that, on average, the full width at half maximum of water peaks was reduced 42%, the full width at tenth maximum was reduced 38%, and the asymmetries of the peaks were reduced 86%. SPECTRAL RESOLUTION DEFINES the ability to distinguish two closely spaced peaks in a spectrum. It is one of the most important determinants of the quality of MR spectroscopy (MRS) data (1-3). Low spectral resolution can obscure the information available from a spectrum of tissue metabolites, hindering the detection and quantification of some or all of those metabolites. This is especially true for in vivo proton MRS ( 1 H MRS) of the brain, for several reasons. First, the differences in the chemical shifts of brain metabolites are relatively small (i.e., the spectral peaks are close to one another), and the line splitting caused by J-coupling further reduces the separation of the peaks in the spectrum. Consequently, some spectral lines overlap intrinsically and cannot be easily distinguished. Second, inhomogeneities of the magnetic field caused by the spatial variation of the external field, B 0 , and by the local differences in magnetic susceptibility of different tissues, produce line broadening and distortion of the lineshape, thereby reducing spectral resolution. Consequently, some lines that are intrinsically separated may overlap. Third, motion of the tissue being imaged may produce line broadening and reduce spectral resolution. ConclusionMany techniques have been developed to improve the spectral resolution of in vivo MRS. These techniques generally fall into one of two classes, depending on whether they are used during the acquisition or the processing of spectral data. The most commonly used strategy for improving spectral resolution during data acquisition is to improve the homogeneity of the main magnetic field, B 0 . Fast, high-order shimming techniques (4) have been implemented on modern scanners, yet these methods cannot eliminate variations in the local magnetic field across the imaging volume that are caused by differing magnetic susceptibilities of the various tissues that are interposed within the body. Another strategy to increase spectral resolu...

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Reference deconvolution: A simple and effective method for resolution enhancement in nuclear magnetic resonance spectroscopy

Cited by 22 publications

References 37 publications

In-Cell NMR Characterization of the Secondary Structure Populations of a Disordered Conformation of α-Synuclein within E. coli Cells

In-Cell NMR Characterization of the Secondary Structure Populations of a Disordered Conformation of α-Synuclein within E. coli Cells

Efficient 1H-NMR Quantitation and Investigation of N-Acetyl-D-glucosamine (GlcNAc) and N,N'-Diacetylchitobiose (GlcNAc)2 from Chitin

Spectral resolution amelioration by deconvolution (SPREAD) in MR spectroscopic imaging

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