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

Within one hour following MCA-occlusion in cats, heavily diffusion-weighted spin-echo MR images exhibited a well-defined hyperintensity in the gray matter and basal ganglia of the occluded side over normal side. This hyperintensity correlated with lactate and inorganic phosphate increases in peak areas from MR surface coil spectroscopy. T2-weighted MRI showed no significant abnormality in signal intensity from the occluded hemisphere within several hours post-occlusion. Using a paramagnetic MR contrast agent, dysprosium-DTPA-BMA together with heavily T2-weighted spin-echo or with T2*-weighted echo-planar (EPI) MR imaging, perfusion deficits resulting from MCA-occlusion were detected as a relative hyperintensity of ischaemic tissues compared to normally-perfused cerebral tissues in the contralateral hemisphere. Evidence of these deficits was observed within minutes of occlusion, and spatially correlated well with the hyperintensity seen on the diffusion-weighted images. Diffusion- and susceptibility-weighted MRI was superior to conventional T2-weighted MRI in the detection of early ischaemic events. In contrast to surface coil spectroscopy, both techniques mapped regions of jeopardy throughout the brain, which later showed T2-weighted hyperintensity and lack of vital (TTC) staining.
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PMID:Early detection of ischemic injury: comparison of spectroscopy, diffusion-, T2-, and magnetic susceptibility-weighted MRI in cats. 208 96

The development of new non-ionic magnetic resonance (MR) contrast media as gadodiamide injection increased the choice of paramagnetic contrast agents available in MR of the central nervous system (CNS). The purpose of our paper was to compare at the dose of 0.1 mmol/kg b.w. the safety of gadodiamide (Gd-DTPA-BMA) to gadopentetate dimeglumine (Gd-DTPA) and to gadoterate meglumine (Gd-DOTA) in two multicentric double-blind studies. A total of 551 patients were enrolled with 143 patients in the Gd-DTPA group, 132 patients in the Gd-DOTA group and 276 patients in the Gd-DTPA-BMA group. Safety was assessed by recording the adverse events up to 24 hours after the injection. One or more adverse events were recorded in 14% of the Gd-DTPA patients, in 15.1% of the Gd-DOTA patients and in 11.6% of the Gd-DTPA-BMA patients. These reactions were related to the contrast media in 9.1%, 13.6% and 8.7% of the cases respectively. Their intensity was defined as mild in 8.4% of the patients in the Gd-DTPA group, in 13.6% of the patients in the Gd-DOTA group and in 8.3% of the patients in the Gd-DTPA-BMA group. No severe reaction or death were recorded. An injection-site reaction (heat, coldness, pain) has been observed in 43% of the cases although an adverse event other than local reactions (headache, dizziness, nausea) has been noticed in 57% of the cases. No significant statistical difference was observed between the groups. Gadodiamide is a safe and effective contrast agent in MRI of the CNS in comparison with Gd-DTPA and Gd-DOTA currently in routine use.
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PMID:[Comparative studies of the tolerability of gadodiamide, dimeglumine gadopentetate and meglumine gadoterate in MRI tests of the central nervous system]. 747 75

The purpose of this study was to characterize the contrast caused by a susceptibility MRI contrast agents, on spin echo T2-weighted imaging of reperfused myocardial infarction. Our interest in this model focused on the expected requirement that such agents be compartmentalized in the tissue to cause signal loss on spin echo images, a condition which may not be present in reperfused infarcted myocardium. Accordingly, nine rats were subjected to 2 h of left coronary artery occlusion followed by 3 +/- 0.5 h of reperfusion prior to administration of contrast media. Three sets of MR images were acquired: (a) baseline axial images at the midventricle, both T1-weighted (TR/TE = 300/20) and T2-weighted (TR/TE = 1500/60); (b) T1-weighted images after administering a T1-enhancing agent, Gd-DTPA-BMA (0.2 mmol/kg), to document that contrast media is delivered to the reperfused infarction; and (c) T2-weighted images after administering the susceptibility agent, Dy-DTPA-BMA (1.0 mmol/kg). Gadolinium-enhanced T1 images depicted reperfused infarction as regions with greatly enhanced signal intensity compared with uninfarcted myocardium, indicating that contrast agent was delivered to the infarcted zone. Dysprosium-enhanced T2 images depicted the injury as a region of persistent signal intensity relative to depletion of signal in normal myocardium, consistent with failure of the contrast agent to cause signal loss. Similar infarction sizes were observed for unenhanced T2-weighted images (33 +/- 5%), gadolinium-enhanced T1-weighted images (36 +/- 5%) and postmortem staining (30 +/- 6%); strong correlations (r > 0.9) were noted in comparisons of these data.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reperfused myocardial infarctions on T1- and susceptibility-enhanced MRI: evidence for loss of compartmentalization of contrast media. 812 Dec 66

Sprodiamide Injection (S-043 Injection, Nycomed Salutar; WIN 59080, Sterling Winthrop) is a magnetic susceptibility-based MRI contrast agent which contains 500 mM dysprosium diethylenetriaminepentaacetic acid bis(methylamide) (DyDTPA-BMA), and 25 mM caldiamide sodium (CaNaDTPA-BMA). A study was conducted to evaluate clearance of drug in cynomolgus monkeys. Eighteen cynomolgus monkeys, divided into three groups of six animals each, were administered Sprodiamide Injection intravenously at dose levels of 0.25, 0.5 and 2.5 mmol kg-1, respectively. The concentration of dysprosium in serum was determined in a monkey serum-hydrochloric acid matrix by inductively-coupled plasma atomic emission spectrometry (ICP-AES). The ICP-AES method was demonstrated to be valid for sensitivity, precision, accuracy, and specificity. The dynamic range was linear from 0 to 50 micrograms ml-1 and the limit of quantification was 24 ng ml-1. The measured dysprosium concentration in monkey serum ranged from 0 to 339 micrograms ml-1 for the 0.25 mmol kg-1 Sprodiamide Injection dose group, from 0 to 633 micrograms ml-1 for the 0.5 mmol kg-1 and from 0 to 2920 micrograms ml-1 for 2.5 mmol kg-1 dose groups. Dysprosium was not detected after 480 min in any of the serum samples from the 0.25 and 0.5 mmol kg-1 dose groups after the administration of Sprodiamide Injection. All the monkeys in the 2.5 mmol kg-1 dose group, with one exception, required 720 min for clearance of the drug from the serum. The drug was completely cleared from serum in all monkeys within 24 h.
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PMID:Determination of dysprosium in monkey serum by inductively-coupled plasma atomic emission spectrometry (ICP-AES) after the administration of Sprodiamide Injection, a new contrast medium for magnetic resonance imaging. 812 24

Seventy-nine patients with known or suspected central nervous system lesions were studied with MRI in a phase III double-blind study. Forty were given gadopentetate dimeglumine (Gd-DTPA) and 39 gadodiamide injection (Gd-DTPA BMA), a new low-osmolar nonionic contrast enhancing medium. The dosage was 0.1 mmol/kg body weight, corresponding to 0.2 ml/kg. Spin-echo sequences were performed before and immediately after injection. The safety and efficacy of the two contrast media were assessed. No changes were observed in blood pressure, heart rate or neurological status. Five adverse effects (two episodes of headaches, two of nausea and one of dizziness) were reported by 2 patients who received gadodiamide injection and 1 who received gadopentetate dimeglumine. All events were mild and their relationship to the contrast media was uncertain. For both contrast media statistically significant changes in serum iron were observed 24 h after injection. More than 70% of the patients had abnormal findings on MRI, and in 56% of these contrast enhancement of the abnormal structure or lesion was seen. Contrast enhancement provided the diagnosis in about 50%, changed it in 40% and increased diagnostic confidence in 95%.
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PMID:A double-blind, comparative study of gadodiamide injection and gadopentetate dimeglumine in MRI of the central nervous system. 845 13

To determine whether intracerebral distribution of clot emboli can induce perfusion deficits and ischemic brain injury in a rat embolism model, diffusion/perfusion magnetic resonance imaging techniques were employed using a 4.7 Tesla imager. Clot emboli produced from venous blood were injected into the right internal carotid artery of male Sprague-Dawley rats. Diffusion-weighted spin-echo imaging was used to detect early ischemic injuries due to cytotoxic edema every 30 minutes. Sequential echo-planar imaging (EPI), as a form of perfusion imaging, was carried out following bolus i.v. injection of the magnetic susceptibility contrast agent Dy DTPA-BMA. Images (EPI) were also made during clot embolization to localize the distribution of the emboli. The images obtained showed signal loss in the right hemisphere corresponding to the distribution of the emboli result of the magnetic susceptibility effect of deoxyhemoglobin. The spatial distribution of the signal loss corresponded to the perfusion deficits, decreased ADC (apparent diffusion coefficient) areas on diffusion images, and histological abnormalities on TTC-stained specimens. After intra-arterial streptokinase infusion following clot embolization, decreased perfusion deficits and abnormal ADC areas were monitored by diffusion/perfusion MRI. Diffusion/perfusion MR imaging thus provided excellent in vivo mapping of the distribution of the emboli in relation to cerebral perfusion deficits and acute ischemic injury in the rat embolism model.
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PMID:[Diffusion/perfusion MRI study on cerebral ischemia in a rat embolism model]. 875 2

We report in vitro T1 and T2 relaxation studies for the open-chain complexes Gd-DTPA and Gd-DTPA BMA. Measurements were performed on phantoms containing aqueous and plasma solutions of different concentrations by MR imaging in a 1.5T superconducting whole-body scanner. Longitudinal relaxation times T1 were evaluated from serial turbo-FLASH experiments for concentrations less than 1 mM, whereas for larger concentrations the values were obtained from a standard inversion recovery (IR) sequence. Transverse relaxation times T2 were determined using multi-echo spin-echo MRI protocols. The T1 and T2 relaxivities of the nonionic Gd-DTPA BMA are similar to those of the Gd-DTPA. The temperature dependencies of the relaxivities were determined over a temperature interval ranging from 21 to 50 degrees C and were found to be slightly different for the two contrast agents. In the case of Gd-DTPA BMA a larger deviation of the expected temperature behavior of the relaxivities was observed as compared with Gd-DTPA. Deviations from a strictly linear dependence of relaxation times on temperature were found at lower concentrations in aqueous solutions. In plasma solutions a high T1/T2 ratio was observed for low concentrations, which decreased monotonically with increasing concentrations.
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PMID:1H T1 and T2 measurements of the MR imaging contrast agents Gd-DTPA and Gd-DTPA BMA at 1.5T. 903 29

Formation of ternary complexes between Gd-DTPA, Gd-DTPA-BMA, and Gd-DOTA, used as contrast enhancement agents in MRI and the endogenously available carbonate and phosphate ions, has been demonstrated. The extent of ternary complex formation and its effect on the proton relaxation, measured at 9 MHz, rates is negligible at around pH < 8. The complex Gd-EDTA forms more stable ternary complexes with carbonate and phosphate and it also strongly coordinates the terdentate citrate ligand. The formation of ternary complexes Gd-EDTA(X) (X = CO3(2-), Cit3-) results in a significant decrease in the proton relaxation rates under physiological conditions.
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PMID:Stability constants and 1H relaxation effects of ternary complexes formed between Gd-DTPA, Gd-DTPA-BMA, Gd-DOTA, and Gd-EDTA and citrate, phosphate, and carbonate ions. 921 90

A multicentre, randomised, double-blind, placebo controlled study to evaluate the efficacy and safety of 4.5 and 9.0 MIU recombinant human interferon alfa-2a (Roferon-A) given thrice weekly in patients with relapsing-remittent multiple sclerosis is described. The patients are treated for 6 months followed by a 6 months drug-free period. The primary objective is to determine new disease activity analysed by monthly MRI with gadodiamide (GdDTPA-BMA, Omniscan). The study is conducted at eight centers in Norway and is completed in January 1996.
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PMID:Treatment of relapsing-remittent multiple sclerosis with recombinant human interferon-alfa-2a: design of a randomised, placebo-controlled, double blind trial in Norway. 934 20

Regional cerebral blood flow (rCBF) was assessed using dynamic susceptibility-contrast MRI at 1.5 T. A simultaneous dual FLASH pulse sequence and Gd-DTPA-BMA (0.3 mmol/kg b.w.) were used for examination of 43 volunteers, measuring rCBF in frontal white matter (WM) and in gray matter in the thalamus (GM). Arterial input functions (AIFs) were registered 1) in the carotid artery and 2) in an artery within the GM/WM slice. The measured concentration-vs. -time curve was deconvolved with the AIF using both Fourier Transform (FT) and Singular Value Decomposition (SVD). Relative rCBF was given by the height of the deconvolved response curve. For each volunteer, eight different rCBF maps were calculated, representing different combinations of deconvolution techniques, AIFs, and filters. The average GM-WM rCBF ratios ranged from 2.0-2.2, depending on methodology. Absolute rCBF was 68 +/- 28 ml/(min 100 g) in GM and 35 +/- 13 ml/(min 100g) in WM (mean +/- SD, n = 39). GM-WM rCBF ratios obtained using SVD were 6-10% higher than corresponding ratios obtained using FT.
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PMID:Assessment of regional cerebral blood flow by dynamic susceptibility contrast MRI using different deconvolution techniques. 1080 34


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