The Experts below are selected from a list of 1617 Experts worldwide ranked by ideXlab platform

Rolf W Gunther - One of the best experts on this subject based on the ideXlab platform.

  • dynamic mri of a hypovascularized liver tumor model comparison of a new Blood Pool contrast Agent 24 gadolinium dtpa cascade polymer with gadopentetate dimeglumine
    Journal of Magnetic Resonance Imaging, 1997
    Co-Authors: J Tacke, Gerhard Adam, Andreas Muhler, Holger Clasen, Andreas Prescher, Rolf W Gunther
    Abstract:

    We evaluated the enhancement properties of a new Blood Pool contrast Agent (24-gadolinium-diethylene-triamine pentaacetic acid [Gd-DTPA]-cascade-polymer) in comparison with gadopentetate dimeglumine in 24 rabbits with an experimentally induced VX-2 liver tumor. Dynamic MRI of the liver was performed before, immediately after, and within 15 seconds to 30 minutes after contrast Agent administration. Relative signal intensities and contrast-to-noise ratios (CNRs) of both Agents were evaluated. After Blood Pool Agent administration, a significantly higher CNR between liver and tumor was observed within 2 to 30 minutes after injection as compared with the CNR after gadopentetate dimeglumine. Within 4 to 30 minutes after injection of gadopentetate dimeglumine, the relative signal intensities of tumor were significantly higher than after administration of the Blood Pool Agent. In conclusion, the new Blood Pool contrast Agent demonstrated a significantly better CNR of the experimental hypovascularized liver tumor than gadopentetate dimeglumine.

  • differentiation of spontaneous canine breast tumors using dynamic magnetic resonance imaging with 24 gadolinium dtpa cascade polymer a new Blood Pool Agent preliminary experience
    Investigative Radiology, 1996
    Co-Authors: Gerhard Adam, Andreas Muhler, E Spuntrup, J Neuerburg, Markus Kilbinger, H Bauer, L Fucezi, W Kupper, Rolf W Gunther
    Abstract:

    RATIONALE AND OBJECTIVES The author assess the enhancement characteristics over time of spontaneous breast tumors in dogs comparing gadopentetate dimeglumine with a new Blood-Pool Agent (24-gadolinium [Gd]-DTPA-cascade polymer). METHODS Eighteen dogs with spontaneous breast tumors (5 carcinomas, 4 adenomas, and 9 benign mixed-tissue tumors) underwent dynamic magnetic resonance imaging after intravenous injection of gadopentetate dimeglumine and the Blood-Pool Agent. Signal intensity time curves were followed up to 30 minutes after injection of both Agents in the same animal. A nonlinear fitting routine enabled calculation of the delivery and clearance half lives of the contrast Agent kinetics in each tumor. RESULTS For gadopentetate dimeglumine, a fast signal increase was found immediately after intravenous injection, with a subsequent signal decay in all tumors. No difference was observed between the enhancement kinetics of different tumor types after gadopentetate dimeglumine application. Similar kinetics were found in benign lesions after injection of the Blood-Pool Agent. However, in carcinomas the Blood-Pool Agent displayed a slower delivery, delayed peak enhancement, and slower tumor tissue clearance or even a signal plateau of more than 30 minutes. CONCLUSIONS Dynamic magnetic resonance imaging of breast neoplasms using a Blood-Pool Agent may help to better differentiate between benign and malignant lesions because it demonstrates the enlarged interstitial space and increased capillary permeability in carcinomas.

  • dynamic contrast enhanced mr imaging of the upper abdomen enhancement properties of gadobutrol gadolinium dtpa polylysine and gadolinium dtpa cascade polymer
    Magnetic Resonance in Medicine, 1994
    Co-Authors: M Gerhard D Adam, Andreas Muhler, E Spuntrup, J Neuerburg, Kira Scherer, Rolf W Gunther
    Abstract:

    The enhancement properties of gadobutrol (40 and 80 mumol/kg body weight, 550 daltons), gadolinium-DTPA-polylysine (20 mumol/kg body weight, 53,000 daltons) and gadolinium-DTPA-cascade-polymer (20 mumol/kg body weight, < 30,000 Daltons) were investigated in abdominal MR imaging using a pig model (n = 24). Signal intensities before and after contrast media application were assessed using a fast single slice FLASH sequence. Measurements were made every 4 s within the first 116 s, every minute between 4 and 10 min and after 15, 20, 30, 40, 50, 60, 90, and 120 min after contrast media injection. Injection of gadobutrol resulted in typical signal intensity curves characterizing it as an extracellular Agent similar to gadopentetate dimeglumine. Significant enhancement was found in all tissues except the trunk muscles when the lower dose was administered. Gadolinium-DTPA-polylysine injection resulted also in significant enhancement of the liver, the pancreas, and the renal cortex, but not of the trunk muscle, reflecting its Blood Pool properties known also from other macromolecular contrast Agents. The signal intensity curves obtained after gadolinium-DTPA-cascade-polymer injection were similar to those obtained after polylysine injection, stressing the Blood Pool character of this new type of Blood Pool Agent.

  • gd dtpa cascade polymer potential Blood Pool contrast Agent for mr imaging
    Journal of Magnetic Resonance Imaging, 1994
    Co-Authors: Gerhard Adam, Andreas Muhler, E Spuntrup, J Neuerburg, Rolf W Gunther
    Abstract:

    Gadolinium-DTPA (diethylenetriaminepentaacetic acid)-cascade-polymer, a potential new Blood Pool contrast Agent for magnetic resonance (MR) imaging, was compared with a known Blood Pool Agent, Gd-DTPA-polylysine, in an animal model. The relative signal intensities of liver, renal cortex, pancreas, and trunk muscle were assessed in 12 pigs between 4 seconds and 120 minutes after injection of a 20 mumol/kg dose of each contrast Agent, by using a FLASH (fast low-angle shot) sequence. Except for muscle, all tissues showed visible enhancement after injection of either contrast Agent. After injection of Gd-DTPA-polymer, enhancement patterns in the liver, renal cortex, and pancreas were similar to those seen after injection of Gd-DTPA-polylysine. No statistically significant differences in enhancement between the two contrast Agents were found at any time point. The authors conclude that the contrast kinetics of Gd-DTPA-cascade-polymer are similar to those of Gd-DTPA-polylysine and that this Agent may also be used as a Blood Pool contrast Agent for MR imaging.

Claire Corot - One of the best experts on this subject based on the ideXlab platform.

  • Contrast-enhanced magnetic resonance angiography in rabbits: evaluation of the gadolinium-based Agent p846 and the iron-based Blood Pool Agent p904 in comparison with gadoterate meglumine.
    Investigative Radiology, 2011
    Co-Authors: Sonja Kinner, Claire Corot, Jörg Barkhausen, Philippe Robert, Stefan Maderwald, Nina Parohl, Juliane Albert, Florian M. Vogt
    Abstract:

    Objectives:To evaluate the performance of a gadolinium-based contrast compound (P846) as well as an ultra-small particle of iron oxide Agent (P904) in contrast-enhanced magnetic resonance angiography (MRA) in rabbits and to compare those Agents with gadoterate meglumine (Gd-DOTA) for first pass and

  • contrast enhanced magnetic resonance angiography p792 Blood Pool Agent versus gd dota in rabbits at 3 0 t versus 1 5 t
    Investigative Radiology, 2007
    Co-Authors: Christoph U Herborn, Claire Corot, Philippe Robert, David M Watkins, Shannon S Baumann, Val M Runge
    Abstract:

    Purpose:To assess the gadolinium-based macromolecular intravascular contrast Agent P792 for magnetic resonance angiography (MRA) at magnetic field strengths of 3.0 T, in comparison to 1.5 T, in rabbits.Materials and Methods:Eleven female New Zealand rabbits of the same age served as the animal model

  • distribution of gadomelitol in a human breast tumor model in mice
    Magnetic Resonance Materials in Physics Biology and Medicine, 2005
    Co-Authors: Claire Corot, Philippe Robert, Eric Lancelot, A Martinell, Robin Santus
    Abstract:

    The study evaluates the tumor distribution of the rapid clearance Blood Pool Agent (RCBPA) gadomelitol, in a breast tumor model. Different techniques were used : (1) tissue gadolinium concentrations measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES), (2) whole body quantitative autoradiography using radiolabeled [153Gd] gadomelitol and (3) dynamic contrast-enhanced MRI with compartmental analysis. An accumulation of gadomelitol in tumors compared to muscle was observed 30 min and 3 h post injection (p.i.). Thirty minutes p.i., the gadomelitol tumor distribution evaluated by autoradiography showed a marked difference between the rim and the center, whereas both areas showed comparable concentrations after 3 h. Using dynamic contrast-enhanced MRI, three phases could be observed during the 1 hour observation period: (1) rapid tumor uptake within the first few minutes post-injection (2) a progressive increase in tumor signal enhancement over 10 min and (3) a steady-state phase. Average +/− SD (n=5) transendothelial permeability KPS and the fractional Blood volume fBV were 12.2±1.6 μl/min−1/g and 5.4±0.2% respectively. Due to its slow extravasation and high tumor residence time, gadomelitol may potentially be useful to improve characterization between benign versus malignant tumors using dynamic MRI.

  • renal functional contrast enhanced magnetic resonance imaging evaluation of a new rapid clearance Blood Pool Agent p792 in sprague dawley rats
    Investigative Radiology, 2005
    Co-Authors: Damien Mandry, Claire Corot, Philippe Robert, Michael Pedersen, Freddy Odille, Jacques Felblinger, N Grenier, M Claudon
    Abstract:

    Objectives: The objective of the present study was to compare P792, a new rapid clearance Blood Pool Agent characterized by negligible interstitial diffusion but unrestricted glomerular filtration, with Gd-DOTA in both qualitative and quantitative aspects of renal functional magnetic resonance imaging.Materials and Methods: Dynamic imaging was performed with a fast T1-weighted gradient-echo sequence on a 1.5-T magnet in 25 Sprague-Dawley rats, after injection of 13 mu mol Gd/kg-1 of P792 (n = 10), 100 (n = 10), or 50 mu mol Gd/kg-1 of Gd-DOTA (n = 5). Signal-time curves from 6 regions of interest (ROIs), including renal parenchyma and contents, were analyzed.Results: Qualitative analysis depicted a typical pattern of temporal enhancement as previously described with extracellular gadolinium chelates, including early and brief enhancement of the aorta, renal vessels and cortex, quickly followed by enhancement of the medulla and then renal pelvis. However, a decrease in signal intensity was noted in the inner medulla and the renal pelvis approximately 90 seconds after bolus injection, being more marked when using the full dose of Gd-DOTA. Curve analysis showed a similar vascular phase within each parenchymal ROI, confirmed by similar upslopes, which ranged from 0.015 +/- 0.007 to 0.019 +/- 0.005. Following this initial phase, T1-enhancement appeared greater and longer within the medulla and renal pelvis, and subsequently in the whole kidney ROI with P792 (time to maximal enhancement (see)/enhancement rate: 85.5 +/- 15.9/3.1 +/- 0.4) as compared with Gd-DOTA full (53.0 +/- 18.9/2.7 +/- 0.3) or half dosage (65.2 +/- 20.1/2.2 +/- 0.2). The subsequent decrease in signal intensity, characterized by a downslope during the minute following maximal enhancement, was faster with Gd-DOTA (0.006 +/- 0.002) as compared either to P792 or half dosage Gd-DOTA (0.003 +/- 0.001).Conclusions: Due to its physicochemical and pharmacokinetic properties, P792 allows the use of a reduced dosage of gadolinium, resulting in less T2(*) effect without compromising T1 enhancement. Thus, P792 appears suitable for renal functional MR imaging.

  • three dimensional navigator coronary mra with the aid of a Blood Pool Agent in pigs improved image quality with inclusion of the contrast Agent first pass
    Journal of Magnetic Resonance Imaging, 2003
    Co-Authors: Martijn S Dirksen, Claire Corot, Theodorus A M Kaandorp, Hildo J Lamb, Joost Doornbos, Albert De Roos
    Abstract:

    Purpose To evaluate the effect of including the first-pass of a Blood Pool Agent (BPA) on the image quality of three-dimensional navigator coronary MRA. Materials and Methods A pig model was used to perform: 1) T1 simulation of the BPA, based on actual Blood samples, and 2) BPA-enhanced three-dimensional navigator coronary MRA, with or without inclusion of the first-pass of the BPA. The acquisitions with inclusion of the first-pass were timed with the use of a test bolus. The acquisitions without first-pass were started one minute after bolus injection (steady-state). A gradient echo acquisition technique with centric k-space sampling was applied. Comparison of both acquisitions was based on determination of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and vessel length. Results T1 simulation shows a distinct T1 reduction during first-pass (to a level below 50 msec), increasing to 190 msec during steady-state. Images obtained with first-pass inclusion showed improved CNR (8.6 ± 1.7 vs. 4.5 ± 1.8), SNR (11.9 ± 1.6 vs. 7.4 ± 2.0), and vessel length (99.2 ± 10.9 mm vs. 60.5 ± 21.8 mm) as compared to the acquisitions during steady-state only (all: P< 0.05). Conclusion The image quality of three-dimensional navigator coronary MRA combined with a gadolinium BPA in pigs is improved when starting the image acquisition during first-pass of the bolus. J. Magn. Reson. Imaging 2003;18:502–506. © 2003 Wiley-Liss, Inc.

Andreas Muhler - One of the best experts on this subject based on the ideXlab platform.

  • dynamic mri of a hypovascularized liver tumor model comparison of a new Blood Pool contrast Agent 24 gadolinium dtpa cascade polymer with gadopentetate dimeglumine
    Journal of Magnetic Resonance Imaging, 1997
    Co-Authors: J Tacke, Gerhard Adam, Andreas Muhler, Holger Clasen, Andreas Prescher, Rolf W Gunther
    Abstract:

    We evaluated the enhancement properties of a new Blood Pool contrast Agent (24-gadolinium-diethylene-triamine pentaacetic acid [Gd-DTPA]-cascade-polymer) in comparison with gadopentetate dimeglumine in 24 rabbits with an experimentally induced VX-2 liver tumor. Dynamic MRI of the liver was performed before, immediately after, and within 15 seconds to 30 minutes after contrast Agent administration. Relative signal intensities and contrast-to-noise ratios (CNRs) of both Agents were evaluated. After Blood Pool Agent administration, a significantly higher CNR between liver and tumor was observed within 2 to 30 minutes after injection as compared with the CNR after gadopentetate dimeglumine. Within 4 to 30 minutes after injection of gadopentetate dimeglumine, the relative signal intensities of tumor were significantly higher than after administration of the Blood Pool Agent. In conclusion, the new Blood Pool contrast Agent demonstrated a significantly better CNR of the experimental hypovascularized liver tumor than gadopentetate dimeglumine.

  • differentiation of spontaneous canine breast tumors using dynamic magnetic resonance imaging with 24 gadolinium dtpa cascade polymer a new Blood Pool Agent preliminary experience
    Investigative Radiology, 1996
    Co-Authors: Gerhard Adam, Andreas Muhler, E Spuntrup, J Neuerburg, Markus Kilbinger, H Bauer, L Fucezi, W Kupper, Rolf W Gunther
    Abstract:

    RATIONALE AND OBJECTIVES The author assess the enhancement characteristics over time of spontaneous breast tumors in dogs comparing gadopentetate dimeglumine with a new Blood-Pool Agent (24-gadolinium [Gd]-DTPA-cascade polymer). METHODS Eighteen dogs with spontaneous breast tumors (5 carcinomas, 4 adenomas, and 9 benign mixed-tissue tumors) underwent dynamic magnetic resonance imaging after intravenous injection of gadopentetate dimeglumine and the Blood-Pool Agent. Signal intensity time curves were followed up to 30 minutes after injection of both Agents in the same animal. A nonlinear fitting routine enabled calculation of the delivery and clearance half lives of the contrast Agent kinetics in each tumor. RESULTS For gadopentetate dimeglumine, a fast signal increase was found immediately after intravenous injection, with a subsequent signal decay in all tumors. No difference was observed between the enhancement kinetics of different tumor types after gadopentetate dimeglumine application. Similar kinetics were found in benign lesions after injection of the Blood-Pool Agent. However, in carcinomas the Blood-Pool Agent displayed a slower delivery, delayed peak enhancement, and slower tumor tissue clearance or even a signal plateau of more than 30 minutes. CONCLUSIONS Dynamic magnetic resonance imaging of breast neoplasms using a Blood-Pool Agent may help to better differentiate between benign and malignant lesions because it demonstrates the enlarged interstitial space and increased capillary permeability in carcinomas.

  • dynamic contrast enhanced mr imaging of the upper abdomen enhancement properties of gadobutrol gadolinium dtpa polylysine and gadolinium dtpa cascade polymer
    Magnetic Resonance in Medicine, 1994
    Co-Authors: M Gerhard D Adam, Andreas Muhler, E Spuntrup, J Neuerburg, Kira Scherer, Rolf W Gunther
    Abstract:

    The enhancement properties of gadobutrol (40 and 80 mumol/kg body weight, 550 daltons), gadolinium-DTPA-polylysine (20 mumol/kg body weight, 53,000 daltons) and gadolinium-DTPA-cascade-polymer (20 mumol/kg body weight, < 30,000 Daltons) were investigated in abdominal MR imaging using a pig model (n = 24). Signal intensities before and after contrast media application were assessed using a fast single slice FLASH sequence. Measurements were made every 4 s within the first 116 s, every minute between 4 and 10 min and after 15, 20, 30, 40, 50, 60, 90, and 120 min after contrast media injection. Injection of gadobutrol resulted in typical signal intensity curves characterizing it as an extracellular Agent similar to gadopentetate dimeglumine. Significant enhancement was found in all tissues except the trunk muscles when the lower dose was administered. Gadolinium-DTPA-polylysine injection resulted also in significant enhancement of the liver, the pancreas, and the renal cortex, but not of the trunk muscle, reflecting its Blood Pool properties known also from other macromolecular contrast Agents. The signal intensity curves obtained after gadolinium-DTPA-cascade-polymer injection were similar to those obtained after polylysine injection, stressing the Blood Pool character of this new type of Blood Pool Agent.

  • gd dtpa cascade polymer potential Blood Pool contrast Agent for mr imaging
    Journal of Magnetic Resonance Imaging, 1994
    Co-Authors: Gerhard Adam, Andreas Muhler, E Spuntrup, J Neuerburg, Rolf W Gunther
    Abstract:

    Gadolinium-DTPA (diethylenetriaminepentaacetic acid)-cascade-polymer, a potential new Blood Pool contrast Agent for magnetic resonance (MR) imaging, was compared with a known Blood Pool Agent, Gd-DTPA-polylysine, in an animal model. The relative signal intensities of liver, renal cortex, pancreas, and trunk muscle were assessed in 12 pigs between 4 seconds and 120 minutes after injection of a 20 mumol/kg dose of each contrast Agent, by using a FLASH (fast low-angle shot) sequence. Except for muscle, all tissues showed visible enhancement after injection of either contrast Agent. After injection of Gd-DTPA-polymer, enhancement patterns in the liver, renal cortex, and pancreas were similar to those seen after injection of Gd-DTPA-polylysine. No statistically significant differences in enhancement between the two contrast Agents were found at any time point. The authors conclude that the contrast kinetics of Gd-DTPA-cascade-polymer are similar to those of Gd-DTPA-polylysine and that this Agent may also be used as a Blood Pool contrast Agent for MR imaging.

Philippe Robert - One of the best experts on this subject based on the ideXlab platform.

  • Contrast-enhanced magnetic resonance angiography in rabbits: evaluation of the gadolinium-based Agent p846 and the iron-based Blood Pool Agent p904 in comparison with gadoterate meglumine.
    Investigative Radiology, 2011
    Co-Authors: Sonja Kinner, Claire Corot, Jörg Barkhausen, Philippe Robert, Stefan Maderwald, Nina Parohl, Juliane Albert, Florian M. Vogt
    Abstract:

    Objectives:To evaluate the performance of a gadolinium-based contrast compound (P846) as well as an ultra-small particle of iron oxide Agent (P904) in contrast-enhanced magnetic resonance angiography (MRA) in rabbits and to compare those Agents with gadoterate meglumine (Gd-DOTA) for first pass and

  • contrast enhanced magnetic resonance angiography p792 Blood Pool Agent versus gd dota in rabbits at 3 0 t versus 1 5 t
    Investigative Radiology, 2007
    Co-Authors: Christoph U Herborn, Claire Corot, Philippe Robert, David M Watkins, Shannon S Baumann, Val M Runge
    Abstract:

    Purpose:To assess the gadolinium-based macromolecular intravascular contrast Agent P792 for magnetic resonance angiography (MRA) at magnetic field strengths of 3.0 T, in comparison to 1.5 T, in rabbits.Materials and Methods:Eleven female New Zealand rabbits of the same age served as the animal model

  • Comprehensive model for simultaneous MRI determination of perfusion and permeability using a Blood-Pool Agent in rats rhabdomyosarcoma
    European Radiology, 2005
    Co-Authors: Cedric Bazelaire, Philippe Robert, Nathalie Siauve, Laure Fournier, Frederique Frouin, Olivier Clement, Eric Kerviler, Charles Andre Cuenod
    Abstract:

    To present a new compartmental analysis model developed to simultaneously measure tissue perfusion and capillary permeability in a tumor using MRI and a macromolecular contrast medium. Rhadomyosarcomas were implanted subcutaneously in 20 rats and studied by 1.5-T MRI using a fast gradient echo sequence (2D fast SPGR TR/TE/α 13 ms/1.2 ms/60°) after injection of a macromolecular contrast medium. The left ventricle and tumor signal intensities were converted into concentrations and modeled using compartmental analysis, yielding tumor perfusion F, distribution volume V_distribution, volume transfer constant K^trans, rate constant of influx k_pe, and initial extraction (fraction) E. Tumor perfusion was F=43±29 ml·min^−1·100 g^−1. The permeability study allowed the measurement of k_pe=0.37±0.12 min^−1 and K^trans=0.01±0.0031 min^−1. The Blood volume could be assimilated to the distribution volume (V_distribution=2.9±1.01%) since the capillary leakage was small. The simultaneous assessment of perfusion and permeability allowed quantification of the initial extraction (fraction) E=2.34±1.05%. Quantification of both tumor perfusion and capillary leakage is feasible using MRI using a macromolecular Blood Pool Agent. The method should improve tumor characterization.

  • distribution of gadomelitol in a human breast tumor model in mice
    Magnetic Resonance Materials in Physics Biology and Medicine, 2005
    Co-Authors: Claire Corot, Philippe Robert, Eric Lancelot, A Martinell, Robin Santus
    Abstract:

    The study evaluates the tumor distribution of the rapid clearance Blood Pool Agent (RCBPA) gadomelitol, in a breast tumor model. Different techniques were used : (1) tissue gadolinium concentrations measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES), (2) whole body quantitative autoradiography using radiolabeled [153Gd] gadomelitol and (3) dynamic contrast-enhanced MRI with compartmental analysis. An accumulation of gadomelitol in tumors compared to muscle was observed 30 min and 3 h post injection (p.i.). Thirty minutes p.i., the gadomelitol tumor distribution evaluated by autoradiography showed a marked difference between the rim and the center, whereas both areas showed comparable concentrations after 3 h. Using dynamic contrast-enhanced MRI, three phases could be observed during the 1 hour observation period: (1) rapid tumor uptake within the first few minutes post-injection (2) a progressive increase in tumor signal enhancement over 10 min and (3) a steady-state phase. Average +/− SD (n=5) transendothelial permeability KPS and the fractional Blood volume fBV were 12.2±1.6 μl/min−1/g and 5.4±0.2% respectively. Due to its slow extravasation and high tumor residence time, gadomelitol may potentially be useful to improve characterization between benign versus malignant tumors using dynamic MRI.

  • renal functional contrast enhanced magnetic resonance imaging evaluation of a new rapid clearance Blood Pool Agent p792 in sprague dawley rats
    Investigative Radiology, 2005
    Co-Authors: Damien Mandry, Claire Corot, Philippe Robert, Michael Pedersen, Freddy Odille, Jacques Felblinger, N Grenier, M Claudon
    Abstract:

    Objectives: The objective of the present study was to compare P792, a new rapid clearance Blood Pool Agent characterized by negligible interstitial diffusion but unrestricted glomerular filtration, with Gd-DOTA in both qualitative and quantitative aspects of renal functional magnetic resonance imaging.Materials and Methods: Dynamic imaging was performed with a fast T1-weighted gradient-echo sequence on a 1.5-T magnet in 25 Sprague-Dawley rats, after injection of 13 mu mol Gd/kg-1 of P792 (n = 10), 100 (n = 10), or 50 mu mol Gd/kg-1 of Gd-DOTA (n = 5). Signal-time curves from 6 regions of interest (ROIs), including renal parenchyma and contents, were analyzed.Results: Qualitative analysis depicted a typical pattern of temporal enhancement as previously described with extracellular gadolinium chelates, including early and brief enhancement of the aorta, renal vessels and cortex, quickly followed by enhancement of the medulla and then renal pelvis. However, a decrease in signal intensity was noted in the inner medulla and the renal pelvis approximately 90 seconds after bolus injection, being more marked when using the full dose of Gd-DOTA. Curve analysis showed a similar vascular phase within each parenchymal ROI, confirmed by similar upslopes, which ranged from 0.015 +/- 0.007 to 0.019 +/- 0.005. Following this initial phase, T1-enhancement appeared greater and longer within the medulla and renal pelvis, and subsequently in the whole kidney ROI with P792 (time to maximal enhancement (see)/enhancement rate: 85.5 +/- 15.9/3.1 +/- 0.4) as compared with Gd-DOTA full (53.0 +/- 18.9/2.7 +/- 0.3) or half dosage (65.2 +/- 20.1/2.2 +/- 0.2). The subsequent decrease in signal intensity, characterized by a downslope during the minute following maximal enhancement, was faster with Gd-DOTA (0.006 +/- 0.002) as compared either to P792 or half dosage Gd-DOTA (0.003 +/- 0.001).Conclusions: Due to its physicochemical and pharmacokinetic properties, P792 allows the use of a reduced dosage of gadolinium, resulting in less T2(*) effect without compromising T1 enhancement. Thus, P792 appears suitable for renal functional MR imaging.

Gerhard Adam - One of the best experts on this subject based on the ideXlab platform.

  • dynamic mri of a hypovascularized liver tumor model comparison of a new Blood Pool contrast Agent 24 gadolinium dtpa cascade polymer with gadopentetate dimeglumine
    Journal of Magnetic Resonance Imaging, 1997
    Co-Authors: J Tacke, Gerhard Adam, Andreas Muhler, Holger Clasen, Andreas Prescher, Rolf W Gunther
    Abstract:

    We evaluated the enhancement properties of a new Blood Pool contrast Agent (24-gadolinium-diethylene-triamine pentaacetic acid [Gd-DTPA]-cascade-polymer) in comparison with gadopentetate dimeglumine in 24 rabbits with an experimentally induced VX-2 liver tumor. Dynamic MRI of the liver was performed before, immediately after, and within 15 seconds to 30 minutes after contrast Agent administration. Relative signal intensities and contrast-to-noise ratios (CNRs) of both Agents were evaluated. After Blood Pool Agent administration, a significantly higher CNR between liver and tumor was observed within 2 to 30 minutes after injection as compared with the CNR after gadopentetate dimeglumine. Within 4 to 30 minutes after injection of gadopentetate dimeglumine, the relative signal intensities of tumor were significantly higher than after administration of the Blood Pool Agent. In conclusion, the new Blood Pool contrast Agent demonstrated a significantly better CNR of the experimental hypovascularized liver tumor than gadopentetate dimeglumine.

  • differentiation of spontaneous canine breast tumors using dynamic magnetic resonance imaging with 24 gadolinium dtpa cascade polymer a new Blood Pool Agent preliminary experience
    Investigative Radiology, 1996
    Co-Authors: Gerhard Adam, Andreas Muhler, E Spuntrup, J Neuerburg, Markus Kilbinger, H Bauer, L Fucezi, W Kupper, Rolf W Gunther
    Abstract:

    RATIONALE AND OBJECTIVES The author assess the enhancement characteristics over time of spontaneous breast tumors in dogs comparing gadopentetate dimeglumine with a new Blood-Pool Agent (24-gadolinium [Gd]-DTPA-cascade polymer). METHODS Eighteen dogs with spontaneous breast tumors (5 carcinomas, 4 adenomas, and 9 benign mixed-tissue tumors) underwent dynamic magnetic resonance imaging after intravenous injection of gadopentetate dimeglumine and the Blood-Pool Agent. Signal intensity time curves were followed up to 30 minutes after injection of both Agents in the same animal. A nonlinear fitting routine enabled calculation of the delivery and clearance half lives of the contrast Agent kinetics in each tumor. RESULTS For gadopentetate dimeglumine, a fast signal increase was found immediately after intravenous injection, with a subsequent signal decay in all tumors. No difference was observed between the enhancement kinetics of different tumor types after gadopentetate dimeglumine application. Similar kinetics were found in benign lesions after injection of the Blood-Pool Agent. However, in carcinomas the Blood-Pool Agent displayed a slower delivery, delayed peak enhancement, and slower tumor tissue clearance or even a signal plateau of more than 30 minutes. CONCLUSIONS Dynamic magnetic resonance imaging of breast neoplasms using a Blood-Pool Agent may help to better differentiate between benign and malignant lesions because it demonstrates the enlarged interstitial space and increased capillary permeability in carcinomas.

  • gd dtpa cascade polymer potential Blood Pool contrast Agent for mr imaging
    Journal of Magnetic Resonance Imaging, 1994
    Co-Authors: Gerhard Adam, Andreas Muhler, E Spuntrup, J Neuerburg, Rolf W Gunther
    Abstract:

    Gadolinium-DTPA (diethylenetriaminepentaacetic acid)-cascade-polymer, a potential new Blood Pool contrast Agent for magnetic resonance (MR) imaging, was compared with a known Blood Pool Agent, Gd-DTPA-polylysine, in an animal model. The relative signal intensities of liver, renal cortex, pancreas, and trunk muscle were assessed in 12 pigs between 4 seconds and 120 minutes after injection of a 20 mumol/kg dose of each contrast Agent, by using a FLASH (fast low-angle shot) sequence. Except for muscle, all tissues showed visible enhancement after injection of either contrast Agent. After injection of Gd-DTPA-polymer, enhancement patterns in the liver, renal cortex, and pancreas were similar to those seen after injection of Gd-DTPA-polylysine. No statistically significant differences in enhancement between the two contrast Agents were found at any time point. The authors conclude that the contrast kinetics of Gd-DTPA-cascade-polymer are similar to those of Gd-DTPA-polylysine and that this Agent may also be used as a Blood Pool contrast Agent for MR imaging.