Relaxation of solvent protons by paramagnetic ions and its dependence on magnetic field and chemical environment: implications for NMR imaging

Koenig, Seymour H.; Brown, Rodney D.

doi:10.1002/mrm.1910010407

Cited by 169 publications

(88 citation statements)

References 55 publications

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“…In the presence of protein, the R 1 relaxivity of gadophrin-2 increases almost twofold to 16 L · mmol Ϫ1 · s Ϫ1 and is highest at protein concentrations of approx. 10%; higher protein concentrations do not significantly increase R 1 , indicating that binding saturation is achieved, at least at the gadophrin-2 concentrations examined (Ͻ1.85 mmol Gd/L) The higher R 1 relaxivity of gadophrin-2 in the presence of protein is most consistent with a decrease in the tumbling rate of the complex by albumin binding (18,19). The increased relaxivity may be responsible in part for detection of small amounts of gadophrin-2 within tumors.…”

Section: Relaxivitymentioning

confidence: 81%

“…Lastly, proton relaxation times of gadophrin-2 were determined in increasing concentrations of albumin, assuming a change of relaxivity in the case of binding because of decreased tumbling rate (18,19). Five different dilutions (1:10, 1:20, 1:40, 1:80, and 1:100 of a 18.5 mmol · L Ϫ1 gadophrin-2 stock solution; based on Gd content) were prepared in water, and 2%, 5%, 10%, and 20% BSA.…”

Section: R 1 Relaxivitymentioning

confidence: 99%

“…MP showed a protein binding of 76% (determined at physiologic concentrations: 50 µmol gadophrin-2/kg BW. Since protein interaction increases relaxivity (19,20), additional titration experiments were performed. R 1 relaxivity of gadophrin-2 in aqueous solution was 9.6 L · mmol Ϫ1 · s Ϫ1 and increased to over 16 L · mmol Ϫ1 · s Ϫ1 when albumin was present.…”

Section: Mechanism Of Accumulation In Necrosismentioning

confidence: 99%

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Mechanism of gadophrin-2 accumulation in tumor necrosis

Hofmann

Bogdanov

Marecos

et al. 1999

J. Magn. Reson. Imaging

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Section: Relaxivitymentioning

confidence: 81%

Section: R 1 Relaxivitymentioning

confidence: 99%

Section: Mechanism Of Accumulation In Necrosismentioning

confidence: 99%

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Mechanism of gadophrin-2 accumulation in tumor necrosis

Hofmann

Bogdanov

Marecos

et al. 1999

J. Magn. Reson. Imaging

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“…Free Mn, with six exchangeable water molecules, has a much higher relaxivity in solution than chelated complexes with one or two exchangeable waters (16,19,20). When administered in vivo, Mn is associated with macromolecules and cellular structures, such as plasma proteins and mitochondria, leading to a reduction in the degrees of rotational freedom and, hence, a great increase in molar relaxivity vs. Mn ion in solution (15).…”

mentioning

confidence: 99%

T1 efficacy of EVP‐ABD: A potential manganese‐based MR contrast agent for hepatic vascular and tissue phase imaging

Chen

Seoane

Lanigan

et al. 2002

Magnetic Resonance Imaging

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Purpose: To evaluate the T1 efficacy of EVP-ABD, a new manganese (Mn)-based contrast agent, for vascular and liver tissue enhancement in comparison with currently approved agents. Materials and Methods:Ten Yorkshire pigs (body weight, 26 -46 kg) were used for the efficacy evaluation, nine for kinetic T1 evaluation (three each agent) and one for post EVP-ABD imaging. With a fast imaging scheme to monitor T1 values of blood and liver, 10 mol/kg EVP-ABD was injected intravenously and compared with gadopentetate dimeglumine (Magnevist, GdDTPA) and mangafodipir trisodium (Teslascan, mangafodipir trisodium) at routine clinical dosages. All were imaged with 3D T1 Gradient Recalled Echo (GRE) sequence (TR/TE/␣ ϭ 3.8/1.6/25°) prior to and 10 minutes post injection using a 1.5-T whole-body scanner. Additional high-resolution 2D liver images (TR/ TE/␣ ϭ 50/4.6/40°) and arterial phase images of the upper aorta were acquired from the pig for post EVP-ABD imaging. Results:At 10 mol/kg, EVP-ABD provided a dramatic decline in blood T1, comparable to 0.1 mmol/kg GdDTPA, followed by a rapid return to blood baseline T1 values. In addition to the blood enhancement phase, EVP-ABD achieved a 70% reduction in liver T1 within 2 minutes postadministration, with an imaging window of at least 2 hours. A substantially improved signal-to-noise ratio (SNR) was observed in both the 2D and 3D liver images postcontrast.Conclusion: EVP-ABD demonstrated peak vascular enhancement similar to GdDTPA and prolonged specific liver enhancement exceeding mangafodipir trisodium. EVP-ABD has favorable T1 enhancing characteristics with the potential to allow for a comprehensive liver evaluation.

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“…That cobalt concentration should produce a substantial effect on the signal intensity in proton MR microscopy. The paramagnetic relaxivity of cobalt(II) ions in solution has been reported (3,4). The molar relaxivity of precipitated cobalt sulphide, however, has not yet been measured but it should be low, since its magnetic susceptibility is only 225 ϫ 10 Ϫ6 cgs (as compared to 12,660 ϫ 10 Ϫ6 cgs for cobalt chloride; Handbook Chem.…”

mentioning

confidence: 99%

MR microscopy of cobalt‐labeled nerve cells and pathways in an invertebrate brain (Sepia officinalis, Cephalopoda)

Quast

Neumeister

Ezell³

et al. 2001

Magnetic Resonance in Med

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This article describes a novel application of contrast-enhanced MR microscopy to trace nerve cells and pathways through small invertebrate brains. Using the cuttlefish Sepia officinalis (Cephalopoda) as a model, the cells and pathways of one of the brain nerves were labeled with paramagnetic cobalt(II) ions by conventional centripetal cobalt iontophoresis. In MR microscopy, the cobalt-labeled cell bodies and pathways became hypointense in 9.4 T spin echo images. Their course and distribution were identical with those seen with conventional histological techniques after cobalt sulphide precipitation (with or without subsequent silver intensification cut-open axon bundles or nerves by bath application and subsequent axonal transport. In addition, cobalt iontophoresis has very successfully been used to distribute the cobalt(II) ions throughout entire nerve cells. The cobalt(II) ions remain within the nerve cells to which they are applied (1) and, when treated with ammonium sulphide (with or without subsequent silver intensification) (2), become visible as black cobalt sulphide precipitate in either whole mounts or histological sections. Since cobalt(II) ions are paramagnetic, a cobalt-labeled cell should alter its local magnetic susceptibility sufficiently to be detectable in proton MRI and, consequently, it should be possible to localize and trace cobalt-labeled nerve cells and pathways by MR microscopy.For conventional cobalt staining a one molar cobalt(II) chloride solution is used. That cobalt concentration should produce a substantial effect on the signal intensity in proton MR microscopy. The paramagnetic relaxivity of cobalt(II) ions in solution has been reported (3,4). The molar relaxivity of precipitated cobalt sulphide, however, has not yet been measured but it should be low, since its magnetic susceptibility is only 225 ϫ 10 Ϫ6 cgs (as compared to 12,660 ϫ 10 Ϫ6 cgs for cobalt chloride; Handbook Chem. Phys.). Therefore cobalt-labeled cells and pathways should more easily be detected by MRI prior to cobalt sulphide precipitation; that is, while the cobalt is still in cobalt(II) chloride form.The use of MR microscopy as a histological tool has been reported (5,6) and the theoretical limits of resolution have been explored (7-9). In addition to being a useful tool in clinical pathology, MR microscopy has numerous applications in biology (10 -13) and neuroscience (14,15). The present study describes a novel application for MR microscopy in neuroanatomy by tracing cobalt-labeled cells and pathways in an invertebrate brain.In the present study the brain of the cuttlefish, Sepia officinalis, was used as a model tissue after one of the brain nerves was labeled with cobalt(II) ions. The cuttlefish brain consists of three distinct masses surrounding the esophagus (the supra-, peri-, and subesophageal masses); each of these is further subdivided into several lobes that are anatomically and functionally described (16). The projections of all the nerves that enter the brain have been histologically analyzed in a numb...

show abstract

Relaxation of solvent protons by paramagnetic ions and its dependence on magnetic field and chemical environment: implications for NMR imaging

Cited by 169 publications

References 55 publications

Mechanism of gadophrin-2 accumulation in tumor necrosis

Mechanism of gadophrin-2 accumulation in tumor necrosis

T1 efficacy of EVP‐ABD: A potential manganese‐based MR contrast agent for hepatic vascular and tissue phase imaging

MR microscopy of cobalt‐labeled nerve cells and pathways in an invertebrate brain (Sepia officinalis, Cephalopoda)

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