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1.
Magn Reson Med ; 82(2): 527-550, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30919510

RESUMO

Proton MRS (1 H MRS) provides noninvasive, quantitative metabolite profiles of tissue and has been shown to aid the clinical management of several brain diseases. Although most modern clinical MR scanners support MRS capabilities, routine use is largely restricted to specialized centers with good access to MR research support. Widespread adoption has been slow for several reasons, and technical challenges toward obtaining reliable good-quality results have been identified as a contributing factor. Considerable progress has been made by the research community to address many of these challenges, and in this paper a consensus is presented on deficiencies in widely available MRS methodology and validated improvements that are currently in routine use at several clinical research institutions. In particular, the localization error for the PRESS localization sequence was found to be unacceptably high at 3 T, and use of the semi-adiabatic localization by adiabatic selective refocusing sequence is a recommended solution. Incorporation of simulated metabolite basis sets into analysis routines is recommended for reliably capturing the full spectral detail available from short TE acquisitions. In addition, the importance of achieving a highly homogenous static magnetic field (B0 ) in the acquisition region is emphasized, and the limitations of current methods and hardware are discussed. Most recommendations require only software improvements, greatly enhancing the capabilities of clinical MRS on existing hardware. Implementation of these recommendations should strengthen current clinical applications and advance progress toward developing and validating new MRS biomarkers for clinical use.


Assuntos
Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Encéfalo/metabolismo , Consenso , Humanos , Prótons
2.
Radiology ; 270(3): 658-79, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24568703

RESUMO

A large body of published work shows that proton (hydrogen 1 [(1)H]) magnetic resonance (MR) spectroscopy has evolved from a research tool into a clinical neuroimaging modality. Herein, the authors present a summary of brain disorders in which MR spectroscopy has an impact on patient management, together with a critical consideration of common data acquisition and processing procedures. The article documents the impact of (1)H MR spectroscopy in the clinical evaluation of disorders of the central nervous system. The clinical usefulness of (1)H MR spectroscopy has been established for brain neoplasms, neonatal and pediatric disorders (hypoxia-ischemia, inherited metabolic diseases, and traumatic brain injury), demyelinating disorders, and infectious brain lesions. The growing list of disorders for which (1)H MR spectroscopy may contribute to patient management extends to neurodegenerative diseases, epilepsy, and stroke. To facilitate expanded clinical acceptance and standardization of MR spectroscopy methodology, guidelines are provided for data acquisition and analysis, quality assessment, and interpretation. Finally, the authors offer recommendations to expedite the use of robust MR spectroscopy methodology in the clinical setting, including incorporation of technical advances on clinical units.


Assuntos
Biomarcadores/metabolismo , Doenças do Sistema Nervoso Central/diagnóstico , Espectroscopia de Ressonância Magnética/métodos , Doenças do Sistema Nervoso Central/metabolismo , Doenças do Sistema Nervoso Central/patologia , Humanos
3.
Front Neuroimaging ; 1: 831216, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37555159

RESUMO

Response to pain therapy is currently by patient self-report. We demonstrate that by evaluating the neurochemistry of a patient, using two-dimensional Correlated SpectroscopY (2D COSY) in a 3T MRI scanner, response to therapy can be recorded. A chronic temporomandibular joint (TMJ) pain patient was evaluated by a pain physician specializing in temporomandibular disorders (TMD), and by 2D COSY, before, and 6 days after treatment with Botulinum Toxin A. Prior to treatment the self-reported pain score was 8/10 and reduced to 0/10 within 24 h of treatment. The neurochemistry of the patient prior to treatment was typical of chronic pain. In particular, the Fuc-α(1-2) glycans were affected. Following treatment, the substrates, α-L Fucose, were elevated and the Fuc-α(1-2) glycans repopulated. The depletion of the molecule assigned the glutathione cysteine moiety, with chronic pain, is indicative of a Glutathione redox imbalance linked to neurodegeneration. This new approach to monitor pain could help discriminate the relative contributions in the complex interplay of the sensory and affective (emotional suffering) components of pain leading to appropriate individualized pharmaceutical drug regimens.

4.
Transl Androl Urol ; 11(7): 929-942, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35958897

RESUMO

Background: Routinely used clinical scanners, such as computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US), are unable to distinguish between aggressive and indolent tumor subtypes in masses localized to the kidney, often leading to surgical overtreatment. The results of the current investigation demonstrate that chemical differences, detected in human kidney biopsies using two-dimensional COrrelated SpectroscopY (2D L-COSY) and evaluated using multivariate statistical analysis, can distinguish these subtypes. Methods: One hundred and twenty-six biopsy samples from patients with a confirmed enhancing kidney mass on abdominal imaging were analyzed as part of the training set. A further forty-three samples were used for model validation. In patients undergoing radical nephrectomy, biopsies of non-cancer kidney cortical tissue were also collected as a non-cancer control group. Spectroscopy data were analyzed using multivariate statistical analysis, including principal component analysis (PCA) and orthogonal projection to latent structures with discriminant analysis (OPLS-DA), to identify biomarkers in kidney cancer tissue that was also classified using the gold-standard of histopathology. Results: The data analysis methodology showed good separation between clear cell renal cell carcinoma (ccRCC) versus non-clear cell RCC (non-ccRCC) and non-cancer cortical tissue from the kidneys of tumor-bearing patients. Variable Importance for the Projection (VIP) values, and OPLS-DA loadings plots were used to identify chemical species that correlated significantly with the histopathological classification. Model validation resulted in the correct classification of 37/43 biopsy samples, which included the correct classification of 15/17 ccRCC biopsies, achieving an overall predictive accuracy of 86%, Those chemical markers with a VIP value >1.2 were further analyzed using univariate statistical analysis. A subgroup analysis of 47 tumor tissues arising from T1 tumors revealed distinct separation between ccRCC and non-ccRCC tissues. Conclusions: This study provides metabolic insights that could have future diagnostic and/or clinical value. The results of this work demonstrate a clear separation between clear cell and non-ccRCC and non-cancer kidney tissue from tumor-bearing patients. The clinical translation of these results will now require the development of a one-dimensional (1D) magnetic resonance spectroscopy (MRS) protocol, for the kidney, using an in vivo clinical MRI scanner.

5.
Radiology ; 259(2): 540-9, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21357517

RESUMO

PURPOSE: To develop an in vivo two-dimensional localized correlation spectroscopy technique with which to monitor the biochemistry of the human brain and the pathologic characteristics of diseases in a clinically applicable time, including ascertainment of appropriate postprocessing parameters with which to allow diagnostic and prognostic molecules to be measured, and to investigate how much of the chemical information, known to be available from malignant cultured cells, could be recorded in vivo from human brain. MATERIALS AND METHODS: The study was approved by the institutional review board and was compliant with HIPAA. With use of a 3.0-T clinical magnetic resonance (MR) unit and a 32-channel head coil, localized correlation spectroscopy was performed in six healthy control subjects and six patients with glioblastoma multiforme (GBM) with an acquisition time of 11 minutes. Two-dimensional spectra were processed and analyzed and peak volume ratios were tabulated. The data used were proved to be normally distributed by passing the Shapiro-Wilk normality test. The first row of the spectra was extracted to examine diagnostic features. The pathologic characteristics and grade of each GBM were determined after biopsy or surgery. Statistically significant differences were assessed by using a t test. RESULTS: The localized correlation spectroscopy method assigned biochemical species from the healthy human brain. The correlation spectra of GBM were of sufficiently high quality that many of the cross peaks, recorded previously from malignant cell models in vitro, were observed, demonstrating a statistically significant difference (P < .05) between the cross peak volumes measured for healthy subjects and those with GBM (which include lipid, alanine, N-acetylaspartate, γ-aminobutyric acid, glutamine and glutamate, glutathione, aspartate, lysine, threonine, total choline, glycerophosphorylcholine, myo-inositol, imidazole, uridine diphosphate glucose, isocitrate, lactate, and fucose). The first row of the spectra was found to contain diagnostic features. CONCLUSION: Localized correlation spectroscopy of the human brain at 3.0 T with use of a 32-channel head coil was performed in 11 minutes and provided information about neurotransmitters, metabolites, lipids, and macromolecules. The method was able to help differentiate healthy brain from the biochemical signature of GBM in vivo. This method may, in the future, reduce the need for biopsy and is now applicable for the study of selected neurologic diseases.


Assuntos
Química Encefálica , Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Neoplasias Encefálicas/patologia , Estudos de Casos e Controles , Meios de Contraste , Feminino , Glioblastoma/patologia , Humanos , Processamento de Imagem Assistida por Computador , Espectroscopia de Ressonância Magnética/instrumentação , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Prospectivos , Fatores de Tempo
6.
J Magn Reson Imaging ; 33(6): 1447-55, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21591015

RESUMO

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.


Assuntos
Encéfalo/patologia , Espectroscopia de Ressonância Magnética/métodos , Músculo Esquelético/patologia , Músculos/patologia , Adulto , Artefatos , Humanos , Lipídeos/química , Masculino , Modelos Teóricos , Imagens de Fantasmas , Ondas de Rádio , Espectrofotometria/métodos
7.
Magn Reson Med ; 64(6): 1542-56, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20890988

RESUMO

Novel low-power adiabatic sequences are demonstrated for in vivo localized two-dimensional correlated MR spectroscopy, such as correlated spectroscopy and total correlated spectroscopy. The design is based on three new elements for in vivo two-dimensional MRS: the use of gradient modulated constant adiabaticity GOIA-W(16,4) pulses for (i) localization (correlated spectroscopy and total correlated spectroscopy) and (ii) mixing (total correlated spectroscopy), and (iii) the use of longitudinal mixing (z-filter) for magnetization transfer during total correlated spectroscopy. GOIA-W(16,4) provides accurate signal localization, and more importantly, lowers the SAR for both total correlated spectroscopy mixing and localization. Longitudinal mixing improves considerably (fivefolds) the efficiency of total correlated spectroscopy transfer. These are markedly different from previous 1D editing total correlated spectroscopy sequences using spatially nonselective pulses and transverse mixing. Fully adiabatic (adiabatic mixing with adiabatic localization) and semiadiabatic (adiabatic mixing with nonadiabatic localization) methods for two-dimensional total correlated spectroscopy are compared. Results are presented for simulations, phantoms, and in vivo two-dimensional spectra from healthy volunteers and patients with brain tumors obtained on 3T clinical platforms equipped with standard hardware. To the best of our knowledge, this is the first demonstration of in vivo adiabatic two-dimensional total correlated spectroscopy and fully adiabatic two-dimensional correlated spectroscopy. It is expected that these methodological developments will advance the in vivo applicability of multi(spectrally)dimensional MRS to reliably identify metabolic biomarkers.


Assuntos
Neoplasias Encefálicas/metabolismo , Aumento da Imagem/métodos , Espectroscopia de Ressonância Magnética/métodos , Algoritmos , Simulação por Computador , Humanos , Aumento da Imagem/instrumentação , Espectroscopia de Ressonância Magnética/instrumentação , Imagens de Fantasmas , Processamento de Sinais Assistido por Computador
8.
AJR Am J Roentgenol ; 193(2): 367-76, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19620433

RESUMO

OBJECTIVE: Personalized health care centers around the concept that each tumor and its host environment is unique; optimal treatment and expected response for any given woman presenting with a newly diagnosed breast cancer differ from the care and response of other women. CONCLUSION: As more is understood about the molecular subtypes of breast cancer and as development of targeted therapies progresses, the possibility of earlier treatment response assessment and even improved detection will be realized.


Assuntos
Neoplasias da Mama/química , Neoplasias da Mama/diagnóstico , Espectroscopia de Ressonância Magnética , Adulto , Idoso , Biópsia , Mama/química , Mama/citologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Carcinoma in Situ/química , Carcinoma in Situ/genética , Carcinoma in Situ/patologia , Carcinoma Ductal/química , Carcinoma Ductal/genética , Carcinoma Ductal/patologia , Diagnóstico Diferencial , Reações Falso-Positivas , Feminino , Fibroma/diagnóstico , Fibroma/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Metástase Linfática , Mamografia/métodos , Pessoa de Meia-Idade , Metástase Neoplásica , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Tomografia por Emissão de Pósitrons , Valores de Referência
9.
AJR Am J Roentgenol ; 193(1): 260-6, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19542422

RESUMO

OBJECTIVE: The purposes of this study were to compare the apparent diffusion coefficient (ADC) of mucinous carcinoma of the breast with that of other breast tumors and to analyze correlations between signal intensity on diffusion-weighted images and the histologic features of mucinous carcinoma. SUBJECTS AND METHODS: Two hundred seventy-six patients with 277 lesions, including 15 mucinous carcinomas (13 pure type, two mixed type), 204 other malignant tumors, and 58 benign lesions, were examined with 1.5-T MRI at b values of 0 and 1,500 s/mm(2). The correlations between cellularity and ADC, homogeneity of signal intensity on diffusion-weighted images, and histopathologic findings were analyzed. The difference was statistically significant (p < 0.05). RESULTS: The mean ADC of mucinous carcinoma (1.8 +/- 0.4 x 10(-3) mm(2)/s) was statistically higher than that of benign lesions (1.3+/- 0.3 x 10(-3) mm(2)/s) and other malignant tumors (0.9 +/- 0.2 x 10(-3) mm(2)/s) (p < 0.001). The ADC of pure type mucinous carcinoma (1.8 +/- 0.3 x 10(-3) mm(2)/s) was higher than that of mixed type mucinous carcinoma (1.2 +/- 0.2 x 10(-3) mm(2)/s) (p < 0.001) and other histologic types (p > 0.05). The correlation between mean cellularity and the ADC of mucinous carcinoma was significant (rho(s) = -0.754; p = 0.001). The homogeneity of signal intensity on diffusion-weighted images correlated with the homogeneity of histologic structures of mucinous carcinoma (p < 0.001; kappa = 0.826). CONCLUSION: Mucinous carcinoma can be clearly differentiated from other breast tumors on the basis of ADC. The low signal intensity of mucinous carcinoma on diffusion-weighted images appears to reflect the presence of mucin and low cellularity. High signal intensity on diffusion-weighted images may reflect the presence of fibrovascular bundles, increased cell density, or a combination of these features.


Assuntos
Adenocarcinoma Mucinoso/patologia , Algoritmos , Neoplasias da Mama/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Interpretação de Imagem Assistida por Computador/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Aumento da Imagem/métodos , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Estatística como Assunto
11.
Anesth Analg ; 102(4): 1164-8, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16551917

RESUMO

Magnetic resonance (MR) spectroscopy is a noninvasive technique that can be used to detect and measure the concentration of metabolites and neurotransmitters in the brain and other organs. We used in vivo (1)H MR spectroscopy in subjects with low back pain compared with control subjects to detect alterations in biochemistry in three brain regions associated with pain processing. A pattern recognition approach was used to determine whether it was possible to discriminate accurately subjects with low back pain from control subjects based on MR spectroscopy. MR spectra were obtained from the prefrontal cortex, anterior cingulate cortex, and thalamus of 32 subjects with low back pain and 33 control subjects without pain. Spectra were analyzed and compared between groups using a pattern recognition method (Statistical Classification Strategy). Using this approach, it was possible to discriminate between subjects with low back pain and control subjects with accuracies of 100%, 99%, and 97% using spectra obtained from the anterior cingulate cortex, thalamus, and prefrontal cortex, respectively. These results demonstrate that MR spectroscopy, in combination with an appropriate pattern recognition approach, is able to detect brain biochemical changes associated with chronic pain with a high degree of accuracy.


Assuntos
Encéfalo/metabolismo , Dor Lombar/diagnóstico , Dor Lombar/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Giro do Cíngulo/metabolismo , Humanos , Medição da Dor/métodos , Córtex Pré-Frontal/metabolismo , Tálamo/metabolismo
12.
Diagn Microbiol Infect Dis ; 52(2): 101-5, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15964497

RESUMO

Viable cryptococci load in biopsy material from an animal model of cerebral cryptococcoma were correlated with 1H NMR spectra and metabolite profiles. A statistical classification strategy was applied to distinguish among high-resolution 1H NMR spectra acquired from cryptococcomas, glioblastomas, and normal brain tissue. The overall classification accuracy was 100% when a genetic-algorithm-based optimal region selection preceded the development of linear discriminant analysis-based classifiers. The method remained robust despite differences in the microbial load of the cryptococcoma group when harvested at different time points. These results indicate the feasibility of the method for diagnosis without isolation of the pathogenic microorganism and its potential for in vivo diagnosis based on computerized analysis of magnetic resonance spectra.


Assuntos
Encefalopatias/diagnóstico , Encefalopatias/parasitologia , Cryptococcus neoformans/crescimento & desenvolvimento , Meningite Criptocócica/diagnóstico , Ressonância Magnética Nuclear Biomolecular/métodos , Algoritmos , Animais , Encefalopatias/metabolismo , Diagnóstico Diferencial , Análise Discriminante , Modelos Animais de Doenças , Glioblastoma/diagnóstico , Glioblastoma/metabolismo , Processamento de Imagem Assistida por Computador , Masculino , Meningite Criptocócica/metabolismo , Meningite Criptocócica/parasitologia , Ratos , Ratos Endogâmicos WF
13.
Eur J Radiol ; 53(3): 506-13, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15741026

RESUMO

In vivo magnetic resonance (MR) spectroscopy at 1.5T was performed on a large polypoid cutaneous melanoma, and two enlarged lymph nodes containing metastatic melanoma, from three patients. Spectra were acquired in vivo from voxels wholly within the primary tumour or secondary lymph node and were thus uncontaminated by signals from adjacent tissue. Tissue biopsies taken after resection of primary tumours and secondary lymph nodes were examined by 8.5T magnetic resonance spectroscopy (MRS) and the results compared with the in vivo spectra, and with spectra from normal skin and a benign skin lesion. There was good agreement between the dominant features of 1.5T spectra acquired in vivo and 8.5T spectra acquired from resected tissue. However, less intense resonances observed at 8.5T in malignant biopsy tissue were not consistently observed at 1.5T in vivo. In vivo spectra from primary and metastatic melanoma showed high levels of choline metabolites. An intense lactate resonance was also present in the in vivo spectrum of primary melanoma. All 8.5T spectra of biopsies from primary and secondary melanoma showed high levels of choline metabolites and lactate, and additional resonances consistent with elevated levels of taurine, alanine, lysine, and glutamate/glutamine relative to normal and benign tissue. Elevated levels of choline, lactate, taurine, and amino acids appear to be clinically useful markers for identifying the pathology of primary and metastatic melanoma.


Assuntos
Metástase Linfática/patologia , Espectroscopia de Ressonância Magnética , Melanoma/metabolismo , Melanoma/patologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Adulto , Idoso , Humanos , Técnicas In Vitro , Masculino , Prótons
14.
Alzheimers Res Ther ; 7(1): 13, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25780390

RESUMO

INTRODUCTION: The goal was to identify which neurochemicals differ in professional athletes with repetitive brain trauma (RBT) when compared to healthy controls using a relatively new technology, in vivo Localized COrrelated SpectroscopY (L-COSY). METHODS: To achieve this, L-COSY was used to examine five former professional male athletes with 11 to 28 years of exposure to contact sports. Each athlete who had had multiple symptomatic concussions and repetitive sub concussive trauma during their career was assessed by an experienced neuropsychologist. All athletes had clinical symptoms including headaches, memory loss, confusion, impaired judgment, impulse control problems, aggression, and depression. Five healthy men, age and weight matched to the athlete cohort and with no history of brain trauma, were recruited as controls. Data were collected from the posterior cingulate gyrus using a 3 T clinical magnetic resonance scanner equipped with a 32 channel head coil. RESULTS: The variation of the method was calculated by repeated examination of a healthy control and phantom and found to be 10% and 5%, respectively, or less. The L-COSY measured large and statistically significant differences (P ≤0.05), between healthy controls and those athletes with RBT. Men with RBT showed higher levels of glutamine/glutamate (31%), choline (65%), fucosylated molecules (60%) and phenylalanine (46%). The results were evaluated and the sample size of five found to achieve a significance level P = 0.05 and a power of 90%. Differences in N-acetyl aspartate and myo-inositol between RBT and controls were small and were not statistically significance. CONCLUSIONS: A study of a small cohort of professional athletes, with a history of RBT and symptoms of chronic traumatic encephalopathy when compared with healthy controls using 2D L-COSY, showed elevations in brain glutamate/glutamine and choline as recorded previously for early traumatic brain injury. For the first time increases in phenylalanine and fucose are recorded in the brains of athletes with RBT. Larger studies utilizing the L-COSY method may offer an in-life method of diagnosis and personalized approach for monitoring the acute effects of mild traumatic brain injury and the chronic effects of RBT.

15.
Am J Surg ; 185(3): 232-8, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12620562

RESUMO

BACKGROUND: Barrett's esophagus is thought to be a precursor of adenocarcinoma. The incidence of adenocarcinoma of the lower esophagus in the Western world is rising and accounts for more than 40% of esophageal carcinomas in males. It is not possible to identify which Barrett's patients are at high risk of developing malignancy. Here we applied a statistical classification strategy to the analysis of magnetic resonance spectroscopy and histopathological data from esophageal biopsies to ascertain whether this risk could be identified in Barrett's patients. METHODS: Tissue specimens from 72 patients (29 noncancer-bearing and 43 cancer-bearing) were analyzed by one-dimensional proton magnetic resonance spectroscopy at 8.5 Tesla. Diagnostic correlation was performed between the magnetic resonance spectra and histopathology. The magnetic resonance magnitude spectra were preprocessed, followed by identification of optimal spectral regions, and were then classified by cross-validated linear discriminant analysis of rank orders of the first derivative of magnetic resonance spectra. RESULTS: Magnetic resonance spectroscopy combined with a statistical classification strategy analysis distinguished normal esophagus from adenocarcinoma and Barrett's epithelium with an accuracy of 100%. Barrett's epithelium and adenocarcinoma were distinguished with an accuracy of 98.6% but only when 4 of the Barrett's specimens and 7 of the carcinoma specimens, determined to be "fuzzy" (ie, unable to be accurately assigned to either class) were withdrawn. The 7 cancer and 4 Barrett's specimens, determined to be "fuzzy" using the Barrett's versus cancer (B versus C) classifier, were submitted to the other two classifiers (Barrett's versus normal [B versus N] and normal versus cancer [N versus C], respectively). The 4 Barrett's specimens were assigned to Barrett's by the N versus B classifier and to normal (n = 2) or cancer (n = 2) classes by the N versus C classifier. The 7 cancer specimens were crisply assigned to the cancer class (N versus C), or for the B versus N classifier, to the Barrett's class (ie, more similar to Barrett's than to normal tissue). Visual inspection of the spectra from histologically identified Barrett's epithelium showed a gradation from normal to carcinoma. CONCLUSIONS: Proton magnetic resonance spectroscopy of esophageal biopsies combined with a statistical classification strategy data analysis provides a robust diagnosis with a high degree of accuracy for discriminating normal epithelium from esophageal adenocarcinoma and Barrett's esophagus. Different spectral categories of Barrett's epithelium were identified both by visual inspection and by statistical classification strategy, possibly reflecting the risk of future malignant transformation.


Assuntos
Esôfago de Barrett/diagnóstico , Espectroscopia de Ressonância Magnética , Adenocarcinoma/química , Adenocarcinoma/diagnóstico , Adenocarcinoma/patologia , Esôfago de Barrett/classificação , Esôfago de Barrett/metabolismo , Esôfago de Barrett/patologia , Diagnóstico por Computador , Epitélio/química , Epitélio/patologia , Neoplasias Esofágicas/química , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/patologia , Esôfago/anatomia & histologia , Esôfago/química , Humanos , Análise Numérica Assistida por Computador , Sensibilidade e Especificidade
16.
Pathology ; 34(5): 417-22, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12408339

RESUMO

AIM: Apply the statistical classification strategy (SCS) to magnetic resonance spectroscopy (MRS) data from liver biopsies and test its potential to discriminate between normal liver, cirrhotic nodules and nodules of hepatocellular carcinoma with a high degree of accuracy. METHODS: Liver tissue specimens from 54 patients undergoing either partial (hemi) or total hepatectomy were analysed by one-dimensional proton MRS at 8.5 Tesla. Histologically, these specimens were confirmed as normal (n=31), cirrhotic (n=59), and hepatocellular carcinoma (HCC, n=32). Diagnostic correlation was performed between the MR spectra and histopathology. An SCS was applied consisting of pre-processing MR magnitude spectra to identify spectral regions of maximal discriminatory value, and cross-validated linear discriminant analysis. RESULTS: SCS applied to MRS data distinguished normal liver tissue from HCC with an accuracy of 100%. Normal liver tissue was distinguished from cirrhotic liver with an accuracy of 92% and cirrhotic liver was distinguished from HCC with an accuracy of 98%. CONCLUSIONS: SCS applied to proton MRS of liver biopsies provides a robust method to distinguish, with a high degree of accuracy, HCC from both cirrhotic and normal liver.


Assuntos
Carcinoma Hepatocelular/patologia , Cirrose Hepática/patologia , Neoplasias Hepáticas/patologia , Imageamento por Ressonância Magnética/métodos , Lesões Pré-Cancerosas/patologia , Carcinoma Hepatocelular/classificação , Carcinoma Hepatocelular/cirurgia , Humanos , Cirrose Hepática/classificação , Cirrose Hepática/cirurgia , Neoplasias Hepáticas/classificação , Neoplasias Hepáticas/cirurgia , Lesões Pré-Cancerosas/classificação , Lesões Pré-Cancerosas/cirurgia , Prótons , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
Radiol Clin North Am ; 48(5): 1075-88, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20868901

RESUMO

Contrast-enhanced magnetic resonance imaging (MRI), MR spectroscopy, and nuclear medicine sestamibi imaging using technetium-99m methoxyisobutyl isonitrile or positron emission tomography (PET) techniques provide information beyond that of structural imaging by displaying tumor neoangiogenesis, tumor metabolites, increased numbers of tumor cellular mitochondria, and hypermetabolic tumor cells. Much needs to be learned at the molecular level of normal cellular pathways either suppressed or enhanced by tumor-specific molecular changes. These discoveries will allow realization of true individualized patient tumor detection, treatment, and surveillance.

19.
J Magn Reson ; 204(1): 91-8, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20206561

RESUMO

AIM: This study aims to (1) undertake and analyse 1D and 2D MR correlation spectroscopy from human soleus muscle in vivo at 7T, and (2) determine T1 and T2 relaxation time constants at 7T field strength due to their importance in sequence design and spectral quantitation. METHOD: Six healthy, male volunteers were consented and scanned on a 7T whole-body scanner (Siemens AG, Erlangen, Germany). Experiments were undertaken using a 28cm diameter detunable birdcage coil for signal excitation and an 8.5cm diameter surface coil for signal reception. The relaxation time constants, T1 and T2 were recorded using a STEAM sequence, using the 'progressive saturation' method for the T1 and multiple echo times for T2. The 2D L-Correlated SpectroscopY (L-COSY) method was employed with 64 increments (0.4ms increment size) and eight averages per scan, with a total time of 17min. RESULTS: T1 and T2 values for the metabolites of interest were determined. The L-COSY spectra obtained from the soleus muscle provided information on lipid content and chemical structure not available, in vivo, at lower field strengths. All molecular fragments within multiple lipid compartments were chemically shifted by 0.20-0.26ppm at this field strength. 1D and 2D L-COSY spectra were assigned and proton connectivities were confirmed with the 2D method. CONCLUSION: In vivo 1D and 2D spectroscopic examination of muscle can be successfully recorded at 7T and is now available to assess lipid alterations as well as other metabolites present with disease. T1 and T2 values were also determined in soleus muscle of male healthy volunteers.


Assuntos
Creatina/análise , Lipídeos/análise , Espectroscopia de Ressonância Magnética/métodos , Músculo Esquelético/química , Adulto , Humanos , Masculino , Sensibilidade e Especificidade
20.
J Magn Reson ; 203(2): 283-93, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20163975

RESUMO

The purpose of this work was to design and implement constant adiabaticity gradient modulated pulses that have improved slice profiles and reduced artifacts for spectroscopic imaging on 3T clinical scanners equipped with standard hardware. The newly proposed pulses were designed using the gradient offset independent adiabaticity (GOIA, Tannus and Garwood[13]) method using WURST modulation for RF and gradient waveforms. The GOIA-WURST pulses were compared with GOIA-HSn (GOIA based on nth-order hyperbolic secant) and FOCI (frequency offset corrected inversion) pulses of the same bandwidth and duration. Numerical simulations and experimental measurements in phantoms and healthy volunteers are presented. GOIA-WURST pulses provide improved slice profile that have less slice smearing for off-resonance frequencies compared to GOIA-HSn pulses. The peak RF amplitude of GOIA-WURST is much lower (40% less) than FOCI but slightly higher (14.9% more) to GOIA-HSn. The quality of spectra as shown by the analysis of lineshapes, eddy currents artifacts, subcutaneous lipid contamination and SNR is improved for GOIA-WURST. GOIA-WURST pulse tested in this work shows that reliable spectroscopic imaging could be obtained in routine clinical setup and might facilitate the use of clinical spectroscopy.


Assuntos
Aumento da Imagem/instrumentação , Imageamento por Ressonância Magnética/instrumentação , Espectroscopia de Ressonância Magnética/instrumentação , Processamento de Sinais Assistido por Computador/instrumentação , Transdutores , Desenho de Equipamento , Análise de Falha de Equipamento
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