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6. OVERHAUSER-ENHANCED MR IMAGING (OMRI)

Author

Golman, K., Leunbach, I., Ardenkjær-Larsen, J. H., Ehnholm, G. J., Wistrand, L.-G., Petersson, J. S., Järvi, A., and Vahasalo, S.

Published
1998

15. Renal Effects of Iodixanol in Experimental Animals

Author

P Walday, Holtz E, Cornacoff J, Heglund If, and Golman K

Subjects
Male, medicine.medical_specialty, Contrast Media, Renal function, chemistry.chemical_element, 030204 cardiovascular system & hematology, Kidney, Iodine, Iopamidol, Rats, Sprague-Dawley, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, Bolus (medicine), Triiodobenzoic Acids, Internal medicine, medicine, Animals, Humans, Radiology, Nuclear Medicine and imaging, 030212 general & internal medicine, Rats, Wistar, Creatinine, Iotrolan, Radiological and Ultrasound Technology, business.industry, General Medicine, Iodixanol, Rats, Macaca fascicularis, Endocrinology, medicine.anatomical_structure, chemistry, Rabbits, business, medicine.drug
Abstract

The effects of the new nonionic dimeric hexa-iodinated contrast media (CM) iodixanol on renal function and morphology were investigated in 7 independent studies in rats, rabbits and monkeys and compared with other iodinated CM. No significant effect on serum creatinine levels was seen at doses up to and including 5 g I/kg in rats and 10.5 g I/kg in rabbits. An immediate and transient increase in proteinuria was found in rabbits when 10.5 g I/kg was administered as a bolus, and when 12.5 g I/kg was administered as a slow infusion in a comparative study with several CM. Increased serum elimination half-life was shown by measuring serum iodine concentrations after the infusion of 12.5 g I/kg. The effect of a high dose of iodixanol on proteinuria and elimination half-life were in this study in the same range as those of the monomeric nonionic CM, but less pronounced than those of the monomeric ionic CM. Reduced renal capacity was induced in male rats by performing unilateral nephrectomy 4 weeks before i.v. injection of iodixanol or iopamidol (2g I/kg). The administration of CM did not affect renal function monitored as serum concentrations of creatinine and urea. The vacuolation of renal proximal tubular cells and kidney iodine retention were investigated in rats 48 hours after administration of different doses of iodixanol or iotrolan. The no-effect level for vacuolation was 0.5 g I/kg for both CM. Iodine retention was higher in male than females rats, and was higher for iodixanol than iotrolan at the 2 highest dose levels (3 and 5 g I/kg). No difference in iodine retention was found at the other dose levels (0.25-1g I/kg). The reversibility of renal proximal tubular vacuolation after administration of iodixanol was studied in male rats (1.2 g I/kg) and monkeys (1.2 and 3.6 g I/kg). The vacuolation was more pronounced in rats than in monkeys. Vacuolation was completely reversed in all rats 3 weeks after dosing, and 2 of 3 monkeys 3 days after a dose of 1.2 g I/kg. The degree of vacuolation evident in renal percutaneous biopsy specimens from monkeys 14 days after i.v. administration of iodixanol at a dose of 3.5 g I/kg was not significantly different to that in control animals. In conclusion, iodixanol affected renal function to the same degree as did the nonionic monomeric and dimeric comparative media, but to a lesser degree than the ionic monomers. The degree of renal proximal tubular cell vacuolation induced by iodixanol seems to be species-dependent, being less pronounced and more quickly reversed in monkeys than rats.

Published
1995

17. Cardiac metabolism measured noninvasively by hyperpolarized 13C MRI

Author

Golman, K., Petersson, J.S., Magnusson, P., Johansson, E., Chai, C.M., Hansson, G., Mansson, S., Åkeson, Per Arne Gustav, Golman, K., Petersson, J.S., Magnusson, P., Johansson, E., Chai, C.M., Hansson, G., Mansson, S., and Åkeson, Per Arne Gustav

Abstract

Pyruvate is included in the energy production of the heart muscle and is metabolized into lactate, alanine, and CO(2) in equilibrium with HCO(3) (-). The aim of this study was to evaluate the feasibility of using (13)C hyperpolarization enhanced MRI to monitor pyruvate metabolism in the heart during an ischemic episode. The left circumflex artery of pigs (4 months, male, 29-34 kg) was occluded for 15 or 45 min followed by 2 hr of reperfusion. Pigs were examined by (13)C chemical shift imaging following intravenous injection of 1-(13)C pyruvate. (13)C chemical shift MR imaging was used in order to visualize the local concentrations of the metabolites. After a 15-min occlusion (no infarct) the bicarbonate signal level in the affected area was reduced (25-44%) compared with the normal myocardium. Alanine signal level was normal. After a 45-min occlusion (infarction) the bicarbonate signal was almost absent (0.2-11%) and the alanine signal was reduced (27-51%). Due to image-folding artifacts the data obtained for lactate were inconclusive. These studies demonstrate that cardiac metabolic imaging with hyperpolarized 1-(13)C-pyruvate is feasible. The changes in concentrations of the metabolites within a minute after injection can be detected and metabolic maps constructed Udgivelsesdato: 2008/5

Published
2008

18. Echo-planar MR imaging of dissolved hyperpolarized 129Xe.

Author

Månsson, S., Johansson, Edvin, Svensson, J., Olsson, L. E., Ståhlberg, Freddy, Petersson, J. S., Golman, K., Månsson, S., Johansson, Edvin, Svensson, J., Olsson, L. E., Ståhlberg, Freddy, Petersson, J. S., and Golman, K.

Published
2002

43. Cerebral perfusion assessment by bolus tracking using hyperpolarized 13C.

Author

Johansson, E., Månsson, S., Wirestam, R., Svensson, J., Petersson, J.S., Golman, K., and Ståhlberg, F.

Abstract

Cerebral perfusion was assessed with 13C MRI in a rat model after intravenous injections of the 13C-labeled compound bis-1,1-(hydroxymethyl)-1-13C-cyclopropane-D8 in aqueous solutions hyperpolarized by dynamic nuclear polarization (DNP). Since the tracer acted as a direct signal source, several of the problems associated with techniques based on traditional dynamic susceptibility contrast (DSC) MRI contrast agents were avoided. Maps of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) were calculated. The MTT was determined to be 2.8 ± 0.8 sec. However, arterial partial-volume effects in the animal model prevented accurate absolute quantification of CBF and CBV. It was demonstrated that depolarization of the hyperpolarized 13C tracer via relaxation and the imaging sequence had little influence on CBF assessment when the time resolution of the imaging sequence was short compared to the MTT. However, CBV and MTT were increasingly underestimated as MTT or the depolarization rate increased if depolarization was not taken into account. With a modified bolus-tracking theory depolarization could be compensated for, assuming that the depolarization rate was known. Three separate compensation methods were investigated experimentally and by numerical simulations. Magn Reson Med 51:464-472, 2004. © 2004 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Published
2004
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44. ECHO-PLANAR MR IMAGING OF DISSOLVED HYPERPOLARIZED [sup129]Xe.

Author

Månsson, S., Johansson, E., Svensson, J., Olsson, L.E., Ståhlberg, F., Petersson, J.S., and Golman, K.

Subjects
ANGIOPLASTY, MAGNETIC resonance, XENON
Abstract

Evaluates the feasibility of xenon for fast magnetic resonance angioplasty using the echo-planar imaging technique. Dissolution of hyperpolarized xenon in ethanol; Relaxation times of hyperpolarized xenon in ethanol.

Published
2002
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49. Non-invasive estimation of kidney function by X-ray fluorescence analysis. Method for in vivo measurements of iodine-containing contrast media in rabbits

Author

S Mattsson, S Sjöberg, K Liden, T Almen, T Grönberg, and Golman K

Subjects
Radiological and Ultrasound Technology, business.industry, Non invasive, Contrast Media, Spectrometry, X-Ray Emission, Renal function, X-ray fluorescence, chemistry.chemical_element, Kidney Function Tests, Iodine, Fluorescence, Collimated light, Iodine Radioisotopes, Nuclear magnetic resonance, Optics, chemistry, Animals, Humans, In vivo measurements, Radiology, Nuclear Medicine and imaging, Rabbits, business, Analysis method
Abstract

It is shown that quantitative determination of the iodine concentration in the soft tissue of rabbits is possible by in vivo measurements using the X-ray fluorescence technique. The influence on the measurements of variable factors such as weight is negligible, due to the use of a well collimated geometry.

Published
1981

50. Parahydrogen‐induced polarization in imaging: Subsecond 13C angiography

Author

Golman, K., Axelsson, O., Jóhannesson, H., Månsson, S., Olofsson, C., and Petersson, J.S.

Abstract

High nuclear spin polarization of 13C was reached in organic molecules. Enhancements of up to 104, compared to thermal polarization at 1.5 T, were achieved using the parahydrogen‐induced polarization technique in combination with a field cycling method. While parahydrogen has no net polarization, it has a high spin order, which is retained when hydrogen is incorporated into another molecule by a chemical reaction. By subjecting this molecule to a sudden change of the external magnetic field, the spin order is transferred into net polarization. A 13C angiogram of an animal was generated in less than a second. Magn Reson Med 46:1–5, 2001. © 2001 Wiley‐Liss, Inc.

Published
2001
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