Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our aim was to evaluate the usefulness of proton MR spectroscopy ((1)H MRS) in the diagnosis of radiologically atypical brain meningiomas. We studied 37 patients with intracranial meningiomas with MRI and (1)H MRS (TE 136 ms). Their spectra were quantitatively assessed and compared with those of 93 other intracranial brain neoplasms: 15 low-grade and 14 anaplastic astrocytomas, 30 glioblastomas and 34 metastases. The most characteristic features of meningiomas were the presence of alanine, high relative concentrations of choline and glutamine/glutamate and low concentrations of creatine-containing compounds, N-acetyl-containing compounds and lipids. These resonances were assembled in algorithms for two-way differentiation between meningioma and the other tumours. The performance of the algorithms was tested in the 130 patients using the leave-one-out method, with 94% success in differentiating between meningioma and other tumour. Of the 37 meningiomas, five (14%) were thought atypical on MRI, and in only one of these, found to be malignant on histology, was a diagnosis other than meningioma suggested by the algorithm. The other four were correctly classified. We suggest that (1)H MRS provides information on intracranial meningiomas which may be useful in diagnosis of radiologically atypical cases.
 ...
PMID:Utility of proton MR spectroscopy in the diagnosis of radiologically atypical intracranial meningiomas. 1268 13

Yet meningiomas have characteristic neuroimaging features, some other lesions are still confusing with meningiomas. The aim of this study was trying to find the typical (1)H-MRS metabolic factors of histologic subtyped meningiomas, schwannomas, metastases, and other brain tumors for differential diagnosis among them. (1)H-MRS using STEAM (TE/30 ms, TR/2 sec) and PRESS (TE/288 ms, TR/2 sec) sequences were performed on 44 untreated brain tumors. Obtained metabolic patterns from the typical spectra of meningioma, schwannoma, metastasis were compared with each other or other brain tumors to evaluate the usefulness for diagnosis between them. Alanine(Ala) was observed in 15 cases of the 19 meningiomas with a little variation to three histologic subtypes, while minimal lipids were observed in every 19 meningiomas. Elevated glutamate/glutamine(Glx) was detected in 12 cases of the meniningiomas. Increased myo-inositol(mI) was detected in 11 cases of the 13 schwannomas. Dominant lipids signals as well as long-T2 lipids were detected in every metastasis in conjunction with elevated choline (Cho). Enhanced Glx was observed in 4 cases of the 8 metastases without correlation of primary tumor site or types. Hemangiopericytoma showed different spectral patterns from typical meningiomas: only dominant Cho, minimal lipids and absence of Ala or Glx signals. These metabolic patterns in typical tumors may provide a basis for differential diagnosis (average value of chi(2) = 23.33, p < 0.01) between meningiomas and schwannomas as well as metastases. However proton spectral distinction among the different histologic subtypes of meningiomas was not definite.
 ...
PMID:(1)H-MRS metabolic patterns for distinguishing between meningiomas and other brain tumors. 1291 98

The clinical utility of proton MR spectroscopy ((1)H-MRS) has been well demonstrated in the brain, prostate, and breast. The aims of this work were to investigate 1) the feasibility of abdominal and thoracic (1)H-MRS at 3T, 2) the benefits of breathholding to MRS in these regions, and 3) the utility of multiple breathhold averaging for MRS. Breathholding either eliminated or markedly reduced phase and frequency shifts and outer voxel contamination that were associated with the motion of the abdomen and the thorax during breathing. Breathholding was found to be essential to spectroscopic investigation of the thorax. Spectra of renal cell carcinoma metastases in the abdomen and thorax were obtained utilizing multiple breathhold averaging. These spectra exhibited a resonance at 3.2 ppm attributed to the trimethylamine moiety of choline metabolites. The results of this study suggest a practical strategy for implementation of (1)H-MRS in the body.
 ...
PMID:Breathhold abdominal and thoracic proton MR spectroscopy at 3T. 1293 52

There has been a growing research interest in brain tumor classification based on proton magnetic resonance spectroscopy (1H MRS) signals. Four research centers within the EU funded INTERPRET project have acquired a significant number of long echo 1H MRS signals for brain tumor classification. In this paper, we present an objective comparison of several classification techniques applied to the discrimination of four types of brain tumors: meningiomas, glioblastomas, astrocytomas grade II and metastases. Linear and non-linear classifiers are compared: linear discriminant analysis (LDA), support vector machines (SVM) and least squares SVM (LS-SVM) with a linear kernel as linear techniques and LS-SVM with a radial basis function (RBF) kernel as a non-linear technique. Kernel-based methods can perform well in processing high dimensional data. This motivates the inclusion of SVM and LS-SVM in this study. The analysis includes optimal input variable selection, (hyper-) parameter estimation, followed by performance evaluation. The classification performance is evaluated over 200 stratified random samplings of the dataset into training and test sets. Receiver operating characteristic (ROC) curve analysis measures the performance of binary classification, while for multiclass classification, we consider the accuracy as performance measure. Based on the complete magnitude spectra, automated binary classifiers are able to reach an area under the ROC curve (AUC) of more than 0.9 except for the hard case glioblastomas versus metastases. Although, based on the available long echo 1H MRS data, we did not find any statistically significant difference between the performances of LDA and the kernel-based methods, the latter have the strength that no dimensionality reduction is required to obtain such a high performance.
 ...
PMID:Brain tumor classification based on long echo proton MRS signals. 1518 48

To determine if proton magnetic resonance spectroscopy (1H MRS) of thyroid carcinoma is feasible and to determine if 1H MRS spectra of malignant tumors differ from that of normal thyroid tissue. We performed 1H MRS at 1.5 T at echo-times (TE) 136 and 272 ms to examine eight patients with thyroid cancer (primary tumour or nodal metastasis) larger than 1 cm3 in size and five volunteers with normal thyroids. Spectra acquired from six primary tumors (three anaplastic carcinomas, two papillary carcinomas and one follicular carcinoma) and two nodes (two papillary carcinoma metastases) were analyzed in the time-domain using a non-linear least squares fitting algorithm with incorporation of prior knowledge. Choline (3.2 ppm) was identified in all solid carcinomas with a mean choline/creatine of 4.3 at TE 136 ms and 5.4 at TE 272 ms. Ratios for malignant tumors at TE 136 ms ranged from 1.6 in well differentiated follicular carcinoma to 9.4 in anaplastic carcinoma. No choline was detected in normal thyroid tissues. Our results showed that 1H MRS is a feasible technique for the evaluation of malignant thyroid tumors larger than 1 cm3 and that proton spectra of malignant tumors differ from that of normal thyroid tissue.
 ...
PMID:In vivo 1H MR spectroscopy of thyroid carcinoma. 1579

A computer-based decision support system to assist radiologists in diagnosing and grading brain tumours has been developed by the multi-centre INTERPRET project. Spectra from a database of 1H single-voxel spectra of different types of brain tumours, acquired in vivo from 334 patients at four different centres, are clustered according to their pathology, using automated pattern recognition techniques and the results are presented as a two-dimensional scatterplot using an intuitive graphical user interface (GUI). Formal quality control procedures were performed to standardize the performance of the instruments and check each spectrum, and teams of expert neuroradiologists, neurosurgeons, neurologists and neuropathologists clinically validated each case. The prototype decision support system (DSS) successfully classified 89% of the cases in an independent test set of 91 cases of the most frequent tumour types (meningiomas, low-grade gliomas and high-grade malignant tumours--glioblastomas and metastases). It also helps to resolve diagnostic difficulty in borderline cases. When the prototype was tested by radiologists and other clinicians it was favourably received. Results of the preliminary clinical analysis of the added value of using the DSS for brain tumour diagnosis with MRS showed a small but significant improvement over MRI used alone. In the comparison of individual pathologies, PNETs were significantly better diagnosed with the DSS than with MRI alone.
 ...
PMID:Development of a decision support system for diagnosis and grading of brain tumours using in vivo magnetic resonance single voxel spectra. 1676 71

Systemic chemotherapy is effective in only a subset of patients with metastasized colorectal cancer. Therefore, early selection of patients who are most likely to benefit from chemotherapy is desirable. Response to treatment may be determined by the delivery of the drug to the tumor, retention of the drug in the tumor and by the amount of intracellular uptake, metabolic activation and catabolism, as well as other factors. The first aim of this study was to investigate the predictive value of DCE-MRI with the contrast agent Gd-DTPA for tumor response to first-line chemotherapy in patients with liver metastases of colorectal cancer. The second aim was to investigate the predictive value of 5-fluorouracil (FU) uptake, retention and catabolism as measured by localized (19)F MRS for tumor response to FU therapy. Since FU uptake, retention and metabolism may depend on tumor vascularization, the relationship between (19)F MRS and the DCE-MRI parameters k(ep), K(trans) and v(e) was also examined (1). In this study, 37 patients were included. The kinetic parameters of DCE-MRI, k(ep), K(trans) and v(e), before start of treatment did not predict tumor response after 2 months, suggesting that the delivery of chemotherapy by tumor vasculature is not a major factor determining response in first-line treatment. No evident correlations between (19)F MRS parameters and tumor response were found. This suggests that in liver metastases that are not selected on the basis of their tumor diameter, FU uptake and catabolism are not limiting factors for response. The transfer constant K(trans), as measured by DCE-MRI before start of treatment, was negatively correlated with FU half-life in the liver metastases, which suggests that, in metastases with a larger tumor blood flow or permeability surface area product, FU is rapidly washed out from the tumor.
 ...
PMID:Prediction of chemotherapeutic response of colorectal liver metastases with dynamic gadolinium-DTPA-enhanced MRI and localized 19F MRS pharmacokinetic studies of 5-fluorouracil. 1700 86

(1)H MRS is an attractive choice for non-invasively diagnosing brain tumours. Many studies have been performed to create an objective decision support system, but there is not yet a consensus as to the best techniques of MRS acquisition or data processing to be used for optimum classification. In this study, we investigate whether LCModel analysis of short-TE (30 ms), single-voxel tumour spectra provide a better input for classification than the use of the original spectra. A total of 145 histologically diagnosed brain tumour spectra were acquired [14 astrocytoma grade II (AS2), 15 astrocytoma grade III (AS3), 42 glioblastoma (GBM), 41 metastases (MET) and 33 meningioma (MNG)], and linear discriminant analyses (LDA) were performed on the LCModel analysis of the spectra and the original spectra. The results consistently suggest improvement in classification when the LCModel concentrations are used. LDA of AS2, MNG and high-grade tumours (HG, comprising GBM and MET) correctly classified 94% using the LCModel dataset compared with 93% using the spectral dataset. The inclusion of AS3 reduced the accuracy to 82% and 78% for LCModel analysis and the original spectra, respectively, and further separating HG into GBM and MET gave 70% compared with 60%. Generally MNG spectra have profiles that are visually distinct from those of the other tumour types, but the classification accuracy was typically about 80%, with MNG with substantial lipid/macromolecule signals being classified as HG. Omission of the lipid/macromolecule concentrations in the LCModel dataset provided an improvement in classification of MNG (91% compared with 76%). In conclusion, there appears to be an advantage to performing pattern recognition on the quantitative analysis of tumour spectra rather than using the whole spectra. However, the results suggest that a two-step LDA process may help in classifying the five tumour groups to provide optimum classification of MNG with high lipid/macromolecule contributions which maybe misclassified as HG.
 ...
PMID:Linear discriminant analysis of brain tumour (1)H MR spectra: a comparison of classification using whole spectra versus metabolite quantification. 1732 43

This contribution considers the possibilities involved with using functional methods in magnetic resonance imaging (MRI) diagnostics for brain tumors. Of the functional methods available, we discuss perfusion MRI (PWI), diffusion MRI (DWI and DTI) and MR spectroscopy (H-MRS). In cases of brain tumor, PWI aids in grading and better differentiation in diagnostics as well as for pre-therapeutic planning. In addition, the course of treatment, both after chemo- as well as radiotherapy in combination with surgical treatment, can be optimized. PWI allows better estimates of biological activity and aggressiveness in low grade brain tumors, and in the case of WHO grade II astrocytoma showing anaplasically transformed tumor areas, allows more rapid visu-alization and a better prediction of the course of the disease than conventional MRI diagnostics. Diffusion MRI, due to the directional dependence of the diffusion, can illustrate the course and direction of the nerve fibers, as well as reconstructing the nerve tracts in the cerebrum, pons and cerebellum 3-dimensionally. Diffusion imaging can be used for describing brain tumors, for evaluating contralateral involvement and the course of the nerve fibers near the tumor. Due to its operator dependence, DTI based fiber tracking for defining risk structures is controversial. DWI can also not differentiate accurately between cystic and necrotic brain tumors, or between metastases and brain abscesses. H-MRS provides information on cell membrane metabolism, neuronal integrity and the function of neuronal structures, energy metabolism and the formation of tumors and brain tissue necroses. Diagnostic problems such as the differentiation between neoplastic and non-neoplastic lesions, grading cerebral glioma and distinguishing between primary brain tumors and metastases can be resolved. An additional contribution will discuss the control of the course of glial tumors after radiotherapy.
 ...
PMID:[Functional imaging for brain tumors (perfusion, DTI and MR spectroscopy)]. 1750 14

Prostate carcinoma is the most common life-threatening cancer affecting men in the western world. In Germany about 40,600 new cases have to be expected each year. The mortality is around 10%. The major goals of pretherapeutic imaging are to determine the local extent of prostate carcinoma in terms of intraprostate localisation, extracapsular extension (ECE), seminal vesicle invasion (SVI), tumour infiltration into neurovascular bundles, and if this has taken place, into surrounding tissues and organs in the small pelvis, detection of loco-regional metastases via the lymph nodes and of this so, of distant metastases. Exact pretherapeutic diagnosis and staging are essential, because the tumour treatment must be selected in strict dependence on clinical tumour stage and risk profile. Both anatomic and functional molecular imaging of prostate carcinoma have advanced significantly in recent years. When there are problems with diagnosis, e.g. when prostate punch biopsies are negative while the suspicion of prostate carcinoma persists, C-11/F-18 choline PET/CT and MRT/MRS may be helpful in localising the carcinoma, revealing how the carcinoma relates to the surrounding intra- and extraprostatic structures and organs, and making a targeted repeat biopsy possible. Lymphotropic contrast agents are highly promising for accurate nodal staging of prostate carcinoma, but are not yet available for routine clinical use; In these circumstances, the sensitivity of nodal staging with the widely available imaging modalities remains inadequate, and its specificity is also less than optimal. There has been particularly substantial progress in the localisation of local relapse, which can be imaged with contrast-enhanced C-11-choline PET/CT and MRT in most cases when PSA is >0.5-1 ng/ml. 18F-Fluoride PET/CT has proved accurate in the diagnosis of skeletal metastases from prostate carcinoma.
 ...
PMID:[Nuclear imaging of prostate cancer: current status]. 1793 41


<< Previous 1 2 3 4 Next >>