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Query: UNIPROT:Q9BWK5 (MRI)
 85,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Five children with Leigh's disease and progressive neurological symptoms were compared with 14 control children. In all patients, MRI showed bilateral lesions of the putamina and caudate heads. Serum lactate was normal for four of the children, and CSF lactate slightly elevated for three. Volume-selective proton MR spectroscopy (1H-MRS) of the basal ganglia in the Leigh patients revealed elevated lactate, giving further evidence for a defect of energy metabolism in the brain. 1H-MRS is an important tool for non-invasive brain tissue analysis in Leigh's disease, particularly in the absence of peripheral lactate elevation.
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PMID:Proton spectroscopy in five patients with Leigh's disease and mitochondrial enzyme deficiency. 792 34

We report here a glycogen storage myopathy type V associated with multifocal encephalopathy. The patient, a 43-year-old male with increased serum CK, a heavy drinker and smoker, had been affected by generalized epilepsy since age 24, after a cranial injury. He had had a right hemiparesis 2 years before coming to our observation and a transient left hemiparesis the following year. CT and MRI of the brain showed multiple hemispheric lesions consistent with an ischemic process, as suggested by single photon emission tomography of the brain. Muscle biopsy showed a vacuolar myopathy, and myophosphorylase activity was 13% of the normal mean. Phosphorus magnetic resonance spectroscopy (31P-MRS) performed on resting calf muscles showed increased PCr to ATP and decreased PCr to P(i) ratios. During both aerobic and ischemic exercise 31P-MRS failed to show any cytosolic acidification and phosphomonoesters (PME) accumulation, two MRS findings in agreement with McArdle's syndrome diagnosis. Mitochondrial respiration was also affected as shown by a low PCr to P(i) ratio at rest and by a low rate of PCr re-synthesis during recovery from aerobic exercise. This latter finding in McArdle's disease can be explained by decreased mitochondrial substrate availability, which in turn can contribute to the phenotypic manifestations of the disease.
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PMID:Myophosphorylase deficiency affects muscle mitochondrial respiration as shown by 31P-MR spectroscopy in a case with associated multifocal encephalopathy. 772 38

Single voxel 1H double spin-echo MR spectroscopy was used to examine 15 cases of brain metastasis of mammary carcinoma (18 lesions) in relation to Gd-DTPA enhanced MR imaging. For lesions larger than 50% of MRS voxel size, there was significant correlation between Gd-DTPA-enhanced MRI signal and MRS-detected signal of choline (Cho) containing compounds (r = 0.86, P < 0.01; n = 8). The observed loss of correlation when including the smaller lesions was overcome by correcting for partial volume effects (r = 0.69, P < 0.002; n = 18). Metastasis spectra showed increased Cho compared with control spectra, except for those lesions showing detectable lactate (Lact) signal. The detection of Lact in four of the larger lesions coincided with comparatively low levels of creatine (Cr) and Cho and heterogeneous Gd-DTPA enhancement (Cr) and Cho and heterogeneous Gd-DTPA enhancement (ring-enhancement). It was concluded that in brain metastases of mammary carcinoma Lact represents a product of ischemia preceding/during tissue decay resulting in central necrosis, rather than tumor specific metabolism resulting in increased glycolysis.
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PMID:Correlation between choline level and Gd-DTPA enhancement in patients with brain metastases of mammary carcinoma. 780 55

Serial proton magnetic resonance spectroscopy (1H-MRS) studies were performed from immediately after the appearance of sequelae in a patient with the interval form of carbon monoxide (CO) poisoning. The volume of interest was set over the frontal lobe white matter. In the early period a persistent increase in choline was found, which was thought to reflect the course of progressive demyelination. The appearance of lactate and decrease in N-acetylaspartate reflected the point at which neuron injury became irreversible. These were followed later by the finding of irreversible changes on MRI and single photon emission computed tomography. The findings suggest that 1H-MRS may be a useful modality to determine neuron viability and prognosis early in the course of the interval form of CO poisoning.
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PMID:Serial proton magnetic resonance spectroscopy in a patient with the interval form of carbon monoxide poisoning. 782 49

The need for prompt and detailed evaluation of cancers and their treatment is requiring increasingly sophisticated methodologies for in vivo assessment. Morphological detail as provided by CT and MRI has yielded significant advances in diagnostic medicine. In spite of such advances, the means of achieving the clinical goals of improved quality and quantity of life in many cancer patients remain elusive. It is becoming increasingly evident that only with the addition of complementary physiological and biochemical data will further advances occur. While neither in vivo morphological imaging with CT or MRI nor physiological imaging with PET or MRS can provide the resolution of microscopic or cellular level assessment, all can provide macroscopic or regional data. With PET, however, exploration of the kinetics or chemical processes occurring at the cellular level is providing a "biological resolution" not heretofore achieved with in vivo imaging. Application of this complementary morphological and biochemical diagnostic information will likely lead to significant advances in patient management in the immediate future, most of which would probably not be achievable using any individual technique. Efficacy studies should be performed, however, when introducing any new high-technology methodology into clinical practice. A number of retrospective and prospective trials on PET applications in clinical oncology are ongoing sponsored by organizations such as the Institute for Clinical PET and the Western PET Association. Detailed studies also are underway to estimate the "cost" of delivery of PET services to the community (146). Numerous PET feasibility studies in animal models have demonstrated that no one radiotracer serves as the best agent for tumor imaging in all cases. Such studies with radiolabeled amino acids, sugars, and nucleoside derivatives, representatives of the major classes of biomolecules, have demonstrated variable tumor uptake dependent on such parameters as the type of cancer, organ of origin, animal host, and chemical structure of the radioligand. Detailed analysis of tracer uptake using multiple ligands in a variety of animal tumor models and clinical patients suggests that while given types of cancers may be better imaged with certain radiotracers, the use of multitracer imaging provides the specific details necessary for appropriate interpretation of tumor status. In addition, in cases where the diagnosis is uncertain, such information could have a significant impact on patient management by reducing the diagnostic differential. In spite of the many successes achieved with FDG in brain tumor imaging, the most well-known example of the problems that can arise with PET image interpretation is with the use of this agent.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Introduction to imaging brain tumor metabolism with positron emission tomography (PET). 787 78

Based on an inductive RF excitation-detection scheme, a quartz-crystal temperature-measuring device is described for applications in MRI and MRS scanners where strong electric and magnetic fields are present. A quartz-crystal resonator with a high temperature sensitivity (88 ppm/degrees C) is employed as the temperature sensor. Changes in the quartz resonance frequency reflecting temperature variations are detected by a NMR coil multiply tuned to the resonance frequencies of the quartz crystal and the nuclei of interest. This wireless probe is simple to build and is capable of measuring temperature changes from -50 to +150 degrees C. The high frequency linearity of the device in this temperature region ensures a simple calibration procedure and a constant temperature resolution.
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PMID:Wireless precision piezoelectric thermometer using an RF excitation-detection technique with an NMR probe. 792 69

The response of advanced prostatic cancer with metastatic chest wall tumor to high-dose diethylstilbestrol diphosphate (DESP) therapy was monitored by in vivo 31P magnetic resonance spectroscopy (31P MRS) study. A eighty-three year old man with Stage D2 prostatic cancer had been treated with chlormadinone acetate and cyclophosphamide since 1984. He was admitted to our hospital with a chest wall tumor and anemia on May 9, 1992. The elevated PAP, PSA and gamma-Sm levels were also observed. Needle biopsy of the tumor revealed poorly differentiated adenocarcinoma metastatic from the prostatic cancer. The patient received 500 mg of DESP by DIV daily for 10 days, and the tumor was reduced by 54% clinically. The abnormal PAP, PSA and gamma-Sm levels returned to almost normal range by three weeks after the initiation of high-dose DESP therapy, and regression of the tumor was confirmed by the MRI. After the first administration of DESP, the MR spectra of the chest wall tumor showed elevated peaks of phosphomonoesters and phosphodiesters. These substances are related to the membrane metabolism and their increase represents the membranous degeneration of tumor cells. The same changes continued consecuitively for three weeks, and corresponded with the regression of the tumor. In conclusion, these results suggest that in vivo 31P MRS of malignant tumors can be useful for evaluating early response to therapy prior to other clinical examinations.
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PMID:[Monitoring tumor response to therapy by means of 31P magnetic resonance spectroscopy. A case of advanced prostatic cancer with metastatic chest wall tumor]. 802 47

Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) was used to examine whether reduced levels of phosphomonoesters (PME) were correlated with ventricular enlargement in 40 patients with bipolar disorder and 60 age-matched normal control subjects. Ventricular enlargement was assessed by magnetic resonance imaging (1H-MRI) using the following three methods: Evans ratio (ER), Huckman number (HN), and minimum distance of caudate nuclei (MDCN). Although MDCN and ER were significantly larger in the patient group, no significant correlations were found between 31P-MRS and 1H-MRI. PME was negatively correlated with age in bipolar disorder. Decreased levels of PME were found only in bipolar I disorder. Intracellular pH was positively correlated with duration of lithium treatment. These results suggest that the observed PME reduction was not related to ventricular enlargement, but the issue should be further studied with volumetric MRI analysis.
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PMID:Phosphorus-31 magnetic resonance spectroscopy and ventricular enlargement in bipolar disorder. 804 28

Sixty-four samples from six grade 4 astrocytomas were investigated ex vivo by 1H MRS at 360 MHz and subsequently by histopathology to obtain percentages of viable and necrotic tumour and grey and white matter. MR-visible lipids were detected in 87% of tumour samples. Necrotic foci were < 3 x 3 x 6 mm3. The means of the intensities/unit weight tissue of the lipid resonances at 5.33, 2.80, 1.29 and 0.89 ppm were significantly higher (p < 0.05) for three sets of comparisons: samples with 85-100% vs 50-75%; with 50-75% vs 10-40% and with 10-40% vs 0-5% necrosis. For the lipid resonance at 2.04 ppm the difference in the means was significant only for samples with 50-75% compared to those with 85-100% necrosis, because for samples with < 50% necrosis resonances from glutamine and possibly small amounts of glutamate, gamma-aminobutyrate and N-acetylaspartate anions contribute significantly to the spectral area at 2.0 ppm. We conclude that necrotic foci below MRI resolution yield the resonances at 1.3 and 0.9 ppm, and contribute to the intense resonance at 2.0 ppm observed in in vivo 1H spectra of some high grade astrocytomas.
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PMID:1H MRS of high grade astrocytomas: mobile lipid accumulation in necrotic tissue. 808 Jul 17

17O natural abundance imaging in a whole body imager is demonstrated using standard MRI spectrometer and 1H imaging methods. A novel design of a highly sensitive 17O/1H doubly tuned surface head coil is shown. The head probe allows simultaneous acquisition of 17O and 1H images using a single coil. The relatively low 17O signal intensity due to the low natural abundance of 17O (0.037 atom percent) is partially compensated by fast repetition of the pulse sequence, achievable due to the short spin lattice relaxation time, T1. A small number of signal averages (e.g., NEX = 50) is sufficient for obtaining images having signal to noise of about 5:1. Due to the short longitudinal relaxation time of 17O, i.e., 2-5 msec, short TR values can be used. 128 phase encoding steps with TR = 10-25 msec correspond to total acquisition time of 1 to 2.5 min. Due to the small gyromagnetic ratio of 17O and the relatively small gradients in a standard whole body system, i.e. 0.5 G/cm, the image in-plane resolution is about 3 mm and a slice thickness of 15 mm. In vivo 17O MRS and MRI natural abundance spectroscopic signals and images of human brain have been observed. The transverse relaxation time, T2 was found to be 2.00 +/- 0.17 msec at 1.5 T. MRS 17O measurements of signal intensity in the occipital cortex during inhalation of oxygen gas, 21.8% 17O enriched, showed a maximum signal enhancement of 25% within the inhalation period. The rate of the metabolism of oxygen (CMRO2) in the occipital cortex was found to be 1.5 mumole/(g tissue) in good agreement with the value of 1.435 mumole/(g tissue) given in the literature. Current measurements using higher 17O enrichments and larger quantities of 17O enriched oxygen gas will enhance resolution and provide more accurate determination of the rate of oxygen metabolism rate and blood flow. The potential of 17O imaging is thus demonstrated in physiological in vivo studies of cerebral metabolism of oxygen and blood flow.
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PMID:Determination of regional cerebral oxygen consumption in the human: 17O natural abundance cerebral magnetic resonance imaging and spectroscopy in a whole body system. 810 3


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