Abstract:
:We describe the optimal high-level postprocessing of single-voxel (1)H magnetic resonance spectra and assess the benefits and limitations of automated methods as diagnostic aids in the detection of recurrent brain tumor. In a previous clinical study, 90 long-echo-time single-voxel spectra were obtained from 52 patients and classified during follow-up (30/28/32 normal/non-progressive tumor/tumor). Based on these data, a large number of evaluation strategies, including both standard resonance line quantification and algorithms from pattern recognition and machine learning, were compared in a quantitative evaluation. Results from linear and non-linear feature extraction, including ICA, PCA and wavelet transformations, and also the data from resonance line quantification were combined systematically with different classifiers such as LDA, chemometric methods (PLS, PCR), support vector machines and ensemble methods. Classification accuracy was assessed using a leave-one-out cross-validation scheme and the area under the curve (AUC) of the receiver operator characteristic (ROC). A regularized linear regression on spectra with binned channels reached 91% classification accuracy compared with 83% from quantification. Interpreting the loadings of these regressions, we find that lipid and lactate signals are too unreliable to be used in a simple machine rule. Choline and NAA are the main source of relevant information. Overall, we find that fully automated pattern recognition algorithms perform as well as, or slightly better than, a manually controlled and optimized resonance line quantification.
journal_name
NMR Biomedjournal_title
NMR in biomedicineauthors
Menze BH,Lichy MP,Bachert P,Kelm BM,Schlemmer HP,Hamprecht FAdoi
10.1002/nbm.1041subject
Has Abstractpub_date
2006-08-01 00:00:00pages
599-609issue
5eissn
0952-3480issn
1099-1492journal_volume
19pub_type
杂志文章abstract::The emergence and rapid development of activatable contrast agents (CAs), whose relaxivity changes in response to the variation of a specific marker in the surrounding physiological microenvironment, have expanded the scope of MRI beyond anatomical and functional imaging to also convey information at the cellular and ...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.2870
更新日期:2013-07-01 00:00:00
abstract::Although diffusion MRI has shown promise for the characterization of breast cancer, it has low specificity to malignant subtypes. Higher specificity might be achieved if the effects of cell morphology and molecular exchange across cell membranes could be disentangled. The quantification of exchange might thus allow th...
journal_title:NMR in biomedicine
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journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1324
更新日期:2009-04-01 00:00:00
abstract::Chemical exchange saturation transfer (CEST)-derived, pH-weighted, amide proton transfer (APT) MRI has shown promise in animal studies for the prediction of infarction risk in ischemic tissue. Here, APT MRI was translated to patients with acute stroke (1-24 h post-symptom onset), and assessments of APT contrast, perfu...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3048
更新日期:2014-02-01 00:00:00
abstract::A quantitative magnetization transfer (qMT) technique was employed to quantify the ratio of the sizes of the bound and free water proton pools in ex vivo mouse brains. The goal was to determine the pool size ratio sensitivity to myelin. Fixed brains from both shiverer mice and control littermates were imaged. The pool...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1358
更新日期:2009-06-01 00:00:00
abstract::Chemical exchange saturation transfer (CEST) potentially provides the ability to detect small solute pools through indirect measurements of attenuated water signals. However, CEST effects may be diluted by various competing effects, such as non-specific magnetization transfer (MT) and asymmetric MT effects, water long...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3243
更新日期:2015-02-01 00:00:00
abstract::Under normal conditions, the heart mainly relies on fatty acid oxidation to meet its energy needs. Changes in myocardial fuel preference are noted in the diseased and failing heart. The magnetic resonance signal enhancement provided by spin hyperpolarization allows the metabolism of substrates labeled with carbon-13 t...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4243
更新日期:2020-03-01 00:00:00
abstract::Quantification of metabolites is a goal of many biomedical NMR studies. To obtain absolute measurements of metabolite concentrations is often both difficult and time-consuming. In this paper a method for determining metabolite concentrations directly is described and validated. It is applicable to studies of amphibian...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940050306
更新日期:1992-05-01 00:00:00
abstract::The phosphorus NMR spectra of isolated perfused rat liver displays a prominent inorganic phosphate peak at 2.76 +/- 0.05 ppm relative to liver glycerolphosphocholine at 0.49 ppm. From titration curves of phosphorus-containing compounds this corresponds to a pH of 7.4. The spectra also display a shoulder on the promine...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940010207
更新日期:1988-04-01 00:00:00
abstract::The intrinsic nonuniformities in the transmit radiofrequency field from standard quadrature volume resonators at high field are particularly problematic for localized MRS in areas such as the temporal lobe, where a low signal-to-noise ratio and poor metabolite quantification result from destructive B₁⁺ field interfere...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1638
更新日期:2011-08-01 00:00:00
abstract::Organs consist of several types of cells with specialized functions. This cellular localization of function is often referred to as compartmentation. Due to the intrinsic low sensitivity of MR methods it is generally not possible in vivo to obtain images or spectra of single cells. Instead the MRS signal is the sum of...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.692
更新日期:2001-04-01 00:00:00
abstract::Nonbiological total disc replacement is currently being used for the treatment of intervertebral disc (IVD) disease and injury, but these implants are prone to mechanical wear, tear and possible dislodgement. Recently, tissue-engineered total disc replacement (TE-TDR) has been investigated as a possible alternative to...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1651
更新日期:2012-03-01 00:00:00
abstract::The majority of functional MRI studies of pain processing in the brain use the blood oxygenation level-dependent (BOLD) imaging approach. However, the BOLD signal is complex as it depends on simultaneous changes in blood flow, vascular volume and oxygen metabolism. Arterial spin labeling (ASL) perfusion imaging is ano...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2911
更新日期:2013-06-01 00:00:00
abstract::The accurate diagnosis of glioma subtypes is critical for appropriate treatment, but conventional histopathologic diagnosis often exhibits significant intra-observer variability and sampling error. The aim of this study was to investigate whether histogram analysis using an automatically segmented region of interest (...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3153
更新日期:2014-09-01 00:00:00
abstract::Dynamic contrast-enhanced MRI (DCE MRI) has been used to study tumor response to treatment for many years. In this study, the modified full width at half-maximum (mFWHM), calculated from the wash-in slope histogram, is proposed as a parameter for the evaluation of changes in tumor heterogeneity which respond to radiot...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2882
更新日期:2013-04-01 00:00:00
abstract::The background underpinning the clinical use of ultrashort echo time, SPRITE and other pulse sequences for imaging bone and other connective tissues with short T2 is reviewed. Features of the basic physics relevant to UTE imaging are described, including the consequences when the radiofrequency pulse duration is of th...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1100
更新日期:2006-11-01 00:00:00
abstract::A noise figure and noise parameter measurement system was developed that consists of a combination spectrum and network analyzer, preamplifier, programmable power supply, noise source, tuning board, and desktop computer. The system uses the Y-factor method for noise figure calculation and allows calibrations to correc...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3138
更新日期:2014-08-01 00:00:00
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 towar...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1730
更新日期:2012-02-01 00:00:00
abstract::By quantification of brain metabolites, localized brain proton MRS can non-invasively provide biochemical information from distinct regions of the brain. Quantification of short-TE signals is usually based on a metabolite basis set. The basis set can be obtained by two approaches: (1) by measuring the signals of metab...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1234
更新日期:2008-07-01 00:00:00
abstract::The management and treatment of high-grade glioblastoma multiforme (GBM) and solitary metastasis (MET) are very different and influence the prognosis and subsequent clinical outcomes. In the case of a solitary MET, diagnosis using conventional radiology can be equivocal. Currently, a definitive diagnosis is based on h...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3163
更新日期:2014-09-01 00:00:00
abstract::In this work, we report a case study of a stroke model in animals using two methods of quantification of the deviations from Gaussian behaviour: diffusion kurtosis imaging (DKI) and log-normal distribution function imaging (LNDFI). The affected regions were predominantly in grey rather than in white matter. The parame...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2802
更新日期:2012-11-01 00:00:00
abstract::The steady-state distribution of the general anesthetic halothane in different rat tissues, including a renal adenocarcinoma with and without hyperthermia treatment, has been evaluated by in vivo 19F NMR spectroscopy. The 19F spectra of halothane (which is a hydrophobic probe) from within tissue show differences in th...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940060502
更新日期:1993-09-01 00:00:00
abstract::Obesity causes damage to several organs, including the brain. Recent studies have been focusing on understanding the mechanisms through which obesity affects brain structure and function using neuroimaging techniques. A functional biomarker, such as cerebral blood flow (CBF), is a powerful tool that can be used to exp...
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pub_type: 杂志文章
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更新日期:2020-10-01 00:00:00
abstract::While phase imaging with a gradient echo (GRE) sequence is popular, phase imaging with balanced steady-state free precession (bSSFP) has been underexplored. The purpose of this study was to investigate anatomical and functional phase imaging with multiple phase-cycled bSSFP, in expectation of increasing spatial covera...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3699
更新日期:2017-06-01 00:00:00
abstract::Standard functional MRI (fMRI), which includes resting-state or paradigm-driven designs, is widely used in studies of brain function, aging, and disease. These fMRI studies typically use two-dimensional gradient echo-planar imaging, which inherently contains phase data that enables quantitative susceptibility mapping ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3619
更新日期:2017-04-01 00:00:00
abstract::The parameters that characterize the intricate water diffusion in tumors may serve to reveal their distinct pathology. Specifically, the application of diffusion magnetic resonance imaging (MRI) can aid in characterizing breast cancer, as well as monitoring response to therapy. We present here a non-invasive, quantita...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.882
更新日期:2004-06-01 00:00:00
abstract::The current state-of-the-art diagnosis method for deep tissue injury in muscle, a subcategory of pressure ulcers, is palpation. It is recognized that deep tissue injury is frequently preceded by altered biomechanical properties. A quantitative understanding of the changes in biomechanical properties preceding and duri...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4087
更新日期:2019-06-01 00:00:00
abstract::Normal subjects performed voluntary, isometric exercise 1 s contraction, 1 s rest for 10 min) of the first dorsal interosseous (FDI) muscle with a target force of 25, 50 and 100% of the maximal voluntary contraction (MVC) force. 31P NMR spectra were collected continuously before, during and after exercise. Data were a...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940030504
更新日期:1990-10-01 00:00:00
abstract::Electric properties tomography (EPT) derives the patient's electric properties, i.e. conductivity and permittivity, using standard magnetic resonance (MR) systems and standard MR sequences. Thus, EPT does not apply externally mounted electrodes, currents or radiofrequency (RF) probes, as is the case in competing techn...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.3729
更新日期:2017-08-01 00:00:00
abstract::Phosphorus MRSI (31 P-MRSI) using a spiral-trajectory readout at 7 T was developed for high temporal resolution mapping of the mitochondrial capacity of exercising human skeletal muscle. The sensitivity and localization accuracy of the method was investigated in phantoms. In vivo performance was assessed in 12 volunte...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3662
更新日期:2016-12-01 00:00:00