Gadolinium-labeled liposomes: targeted MR contrast agents for the liver and spleen.

Kabalka, George W.; Buonocore, Edward; Hübner, Karl; Moss, T. H.; Norley, N.; Huang, Lynn Ling-Huei

doi:10.1148/radiology.163.1.3454163

Cited by 130 publications

(43 citation statements)

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“…Ordinarily, because every spin's precession frequency is proportional to the local magnetic field, the frequency spectrum I(ω) faithfully mirrors the spin density Diffusion is generally expected to contribute to blurring of images. For example, studies on paramagnetic contrast agents have shown that biological contours are blurred since contrast agents affect not only the tissue compartments to which they are confined but, through diffusive water exchange, also affect surrounding regions (7,8,9,10,11). Thus, one might expect that diffusion blurring should become prevalent in microscopic imaging, yet this may not necessarily be the case.…”

Section: Theorymentioning

confidence: 99%

Edge enhancement by diffusion in microscopic magnetic resonance imaging

Pütz

Barsky

Schulten

1992

Journal of Magnetic Resonance (1969)

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In microscopic MRI (∼ 10 µm resolution), diffusion boundaries impermeable to water on a millisecond time scale distort the line shape function of the observed frequency spectra from the transverse magnetization in a manner similar to motional narrowing in MR spectroscopy. Reconstruction techniques developed for macroscopic imaging interpret these distortions as spatial deformations of objects. This distortion of frequency spectra is demonstrated for geometrically simple objects, and it is shown how in such cases the reconstructed images should be interpreted and how diffusioninduced distortions in frequency space may actually be exploited to enhance image contrast around compartmental boundaries. The distortions are properly described by Kubo's line shape function for which suitable numerical algorithms are provided.A parameter is introduced that provides an estimation of the extent of diffusioninduced distortions which can vary from an enhancement of image intensity near boundaries to, for extreme motional narrowing, a focusing of image intensity around compartment centers.

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Section: Theorymentioning

confidence: 99%

Edge enhancement by diffusion in microscopic magnetic resonance imaging

Pütz

Barsky

Schulten

1992

Journal of Magnetic Resonance (1969)

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“…This myocardial specificity of Gd(BME-DTTA) was also observed in our studies in ferret and dog ischemia models using liposomal Gd(BME-DTTA). 2,12,13 The average particle size of liposomal Gd(BME-DTTA), observed in the electron micrographs, is smaller than 0.125 m. It has been reported that small liposome particles (average 0.1 m) are more effectively taken up by hepatocytes 14,15 and the spleen 16 than larger ones. Therefore, the large IE effects observed in liver and spleen may be attributed to the relatively small size of the liposomal Gd(BME-DTTA) particles.…”

Section: Discussionmentioning

confidence: 99%

In vivo Characterization of Gd(BME-DTTA), a myocardial MRI contrast agent: tissue distribution of its MRI intensity enhancement, and its effect on heart function

1997

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We have determined an LD50 of 0.56±0.05 mmol/kg for liposomal Gd(BME‐DTTA) in mice and also shown that liposomal Gd(BME‐DTTA) has no deleterious effects on heart rate, blood pressure, left ventricular force and AV conductance in ferret hearts in vivo at the magnetic resonance imaging (MRI)‐effective dose of 0.05 mmol/kg body weight. In MRI images, a 1H signal intensity enhancement is observed in the following organs in decreasing order of the effect: heart≈spleen>kidney>liver. This enhancement is stable for over 3 h in all organs. The results of 1H MRI and electron micrographs indicate that the lipophilic fatty acyl groups in the ligand BME structure and the particle sizes of liposomal Gd(BME‐DTTA) are two important factors for tissue specificity of liposomal Gd(BME‐DTTA) in the intensity enhancement. In vitro relaxivity of a liposomal Gd(BME‐DTTA) sample, stored at 4°C, remained stable for over 4 months of observation, but a significant decrease in relaxivity was observed in a sample stored at room temperature, most likely reflecting some deterioration in liposome chemistry. © 1997 John Wiley & Sons, Ltd.

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“…After administration of 50 anoi Fe/kg of fernte, the signal-to-ncise ratio of spleen was significantly (p < .005) less than that of tumor. [22], and liposomes containing paramagnetic ions such as gadolinium [23] or manganese [24]. For all of these drugs, either they are very toxic [20,21] or their toxicity has not been fully studied [ …”

Section: In Vivo Imagingmentioning

confidence: 99%