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David A Bluemke - One of the best experts on this subject based on the ideXlab platform.
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Gadolinium enhanced cardiovascular magnetic resonance administered dose in relationship to united states food and drug administration fda guidelines
Journal of Cardiovascular Magnetic Resonance, 2012Co-Authors: Marcelo Souto Nacif, Andrew E Arai, Joao A C Lima, David A BluemkeAbstract:Myocardial late Gadolinium enhancement was originally validated using higher than label-recommended doses of Gadolinium chelate. The objective of this study was to evaluate available evidence for various Gadolinium dosing regimens used for CMR. The relationship of Gadolinium dose warnings (due to nephrogenic systemic fibrosis) announced in 2008 to Gadolinium dosing regimens was also examined. We conducted a meta-analysis of peer reviewed publications from January, 2004 to December, 2010. Major subject search headings (MeSh) terms from the National Library of Medicine's PubMed were: contrast media, Gadolinium, heart, magnetic resonance imaging; searches were limited to human studies with abstracts published in English. Case reports, review articles, editorials, MRA related papers and all reports that did not indicate Gadolinium type or weight-based dose were excluded. For all included references, full text was available to determine the total administered Gadolinium dose on a per kg basis. Average and median dose values were weighted by the number of subjects in each study. 399 publications were identified in PubMed; 233 studies matched the inclusion criteria, encompassing 19,934 patients with mean age 54.2 ± 11.4 (range 9.3 to 76 years). 34 trials were related to perfusion testing and 199 to myocardial late Gadolinium enhancement. In 2004, the weighted-median and weighted-mean contrast dose were 0.15 and 0.16 ± 0.06 mmol/kg, respectively. Median contrast doses for 2005-2010 were: 0.2 mmol/kg for all years, respectively. Mean contrast doses for the years 2005-2010 were: 0.19 ± 0.03, 0.18 ± 0.04, 0.18 ± 0.10, 0.18 ± 0.03, 0.18 ± 0.04 and 0.18 ± 0.04 mmol/kg, respectively (p for trend, NS). Gadopentetate dimeglumine was the most frequent Gadolinium type [114 (48.9%) studies]. No change in mean Gadolinium dose was present before, versus after the Food and Drug Administration (FDA) black box warning (p > 0.05). Three multi-center dose ranging trials have been published for cardiac MRI applications. CMR studies in the peer-reviewed published literature routinely use higher Gadolinium doses than regulatory agencies indicated in the package leaflet. Clinical trials should be supported to determine the appropriate doses of Gadolinium for CMR studies.
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t1 mapping of the Gadolinium enhanced myocardium adjustment for factors affecting interpatient comparison
Magnetic Resonance in Medicine, 2011Co-Authors: Evrim B Turkbey, Joao A C Lima, David A Bluemke, Saman Nazarian, Rob J Van Der GeestAbstract:Myocardial delayed enhanced (MDE) cardiac magnetic resonance imaging (MRI) is a well-established technique used to evaluate ischemic (1–5) and nonischemic (6–9) disease of the myocardium. The method uses inversion recovery prepared T1 weighted images obtained 5–30 min after administration of a Gadolinium contrast agent. The inversion recovery pulse is set to null normal myocardium, while Gadolinium concentration is greater in regions of focal myocardial scar, resulting in high signal intensity (10). Qualitative evaluation of focal myocardial scar (i.e., from myocardial infarction) is a robust technique that appears to be relatively insensitive to variation in MDE MRI acquisition parameters (11). Gadolinium dose, however, is likely to influence the appearance of myocardial scar (12). On the other hand, diffuse myocardial fibrosis (i.e., from nonischemic cardiomyopathy) may show only minimal variation in signal intensity on MDE MRI, as a single voxel contains a mixture of both normal myocardium and abnormal myocardium. Indeed, in the theoretical case of complete, uniform dispersion of myocardial fibrosis, the inversion pulses used with the MDE technique will uniformly suppress the entire myocardium despite substantial retention of Gadolinium. However, measured T1 times are likely to be reduced in the presence of diffuse fibrosis/collagen, as recently demonstrated in some heart failure subjects (13). Unfortunately, the observed T1 time of the myocardium is affected by multiple parameters besides the extent of collagen deposition. For example, a longer time between the start of the Gadolinium injection to the time of measurement of the T1 map results in longer T1 values due to renal excretion of Gadolinium (14). Renal function and the extravascular volume of distribution of Gadolinium may vary between patients. Iron deposition in certain diseases such as haemochromatosis will shorten T1 times. Cardiac amyloidosis is associated with accumulation of amyloid protein and Gadolinium retention. Although factors such as the timing of injection and imaging, as well as Gadolinium dose are frequently under the control of the investigator, variation in physiologic parameters will confound the comparison of T1 values between patients. Thus, the observed T1 time of the myocardium after Gadolinium administration is a function of both physiologic parameters and MRI acquisition parameters. To derive inferences regarding tissue composition of the myocardium using the Gadolinium technique, it is necessary to understand the influence of physiologic and acquisition parameters. In this study, we determined the sensitivity of MDE T1 maps to both physiologic and MRI acquisition parameters, to correct for changes in these parameters between patients. We derived T1 model parameters from MDE MRI studies on normal volunteers. As an example of how the methods may be applied, we then used these parameters to correct the observed T1 values in a patient population at risk for diffuse myocardial fibrosis.
Kevin C Chan - One of the best experts on this subject based on the ideXlab platform.
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in vivo assessment of aqueous humor dynamics upon chronic ocular hypertension and hypotensive drug treatment using Gadolinium enhanced mri
Investigative Ophthalmology & Visual Science, 2014Co-Authors: Ian P Conner, Seong Gi Kim, Gadi Wollstein, Joel S Schuman, Kevin C ChanAbstract:PURPOSE. Although glaucoma treatments alter aqueous humor (AH) dynamics to lower intraocular pressure, the regulatory mechanisms of AH circulation and their contributions to the pathogenesis of ocular hypertension and glaucoma remain unclear. We hypothesized that Gadolinium-enhanced magnetic resonance imaging (Gd-MRI) can visualize and assess AH dynamics upon sustained intraocular pressure elevation and pharmacologic interventions. METHODS. Gadolinium contrast agent was systemically administered to adult rats to mimic soluble AH components entering the anterior chamber (AC) via blood–aqueous barrier. Dynamic Gd-MRI was applied to examine the signal enhancement in AC and vitreous body upon microbead-induced ocular hypertension and unilateral topical applications of latanoprost, timolol maleate, and brimonidine tartrate to healthy eyes. RESULTS. Gadolinium signal time courses in microbead-induced hypertensive eyes possessed faster initial Gadolinium uptake and higher peak signals in AC than control eyes, reflective of reduced Gadolinium clearance upon microbead occlusion. Opposite trends were observed in latanoprost- and timolol-treated eyes, indicative of their respective drug actions on increased uveoscleral outflow and reduced AH production. The slowest initial Gadolinium uptake but strongest peak signals were found in AC of both brimonidine-treated and untreated fellow eyes. These findings drew attention to the systemic effects of topical hypotensive drug treatment. Gadolinium leaked into the vitreous of microbead-induced hypertensive eyes and brimonidine-treated and untreated fellow eyes, suggestive of a compromise of aqueous– vitreous or blood–ocular barrier integrity.
Donna R. Roberts - One of the best experts on this subject based on the ideXlab platform.
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pediatric patients demonstrate progressive t1 weighted hyperintensity in the dentate nucleus following multiple doses of Gadolinium based contrast agent
American Journal of Neuroradiology, 2016Co-Authors: Donna R. Roberts, Milad Yazdani, B Marebwa, Heather R Collins, G M Bolles, J M Jenrette, Arindam R. Chatterjee, Truman R. Brown, Paul J. NietertAbstract:BACKGROUND AND PURPOSE: While there have been recent reports of brain retention of Gadolinium following Gadolinium-based contrast agent administration in adults, a retrospective series of pediatric patients has not previously been reported, to our knowledge. We investigated the relationship between the number of prior Gadolinium-based contrast agent doses and increasing T1 signal in the dentate nucleus on unenhanced T1-weighted MR imaging. We hypothesized that despite differences in pediatric physiology and the smaller Gadolinium-based contrast agent doses that pediatric patients are typically administered based on weighted-adjusted dosing, the pediatric brain would also demonstrate dose-dependent increasing T1 signal in the dentate nucleus. MATERIALS AND METHODS: We included children with multiple Gadolinium-based contrast agent administrations at our institution. A blinded reader placed ROIs within the dentate nucleus and adjacent cerebellar white matter. To eliminate reader bias, we also performed automated ROI delineation of the dentate nucleus, cerebellar white matter, and pons. Dentate-to-cerebellar white matter and dentate-to pons ratios were compared with the number of Gadolinium-based contrast agent administrations. RESULTS: During 20 years at our institution, 280 patients received at least 5 Gadolinium-based contrast agent doses, with 1 patient receiving 38 doses. Sixteen patients met the inclusion/exclusion criteria for ROI analysis. Blinded reader dentate-to-cerebellar white matter ratios were significantly associated with Gadolinium-based contrast agent doses ( r s = 0.77, P = .001). The dentate-to-pons ratio and dentate-to-cerebellar white matter ratios based on automated ROI placement were also significantly correlated with Gadolinium-based contrast agent doses ( t = 4.98, P t = 2.73, P CONCLUSIONS: In pediatric patients, the number of prior Gadolinium-based contrast agent doses is significantly correlated with progressive T1-weighted dentate hyperintensity. Definitive confirmation of Gadolinium deposition requires tissue analysis. Any potential clinical sequelae of Gadolinium retention in the developing brain are unknown. Given this uncertainty, we suggest taking a cautious stance, including the use, in pediatric patients, of higher stability, macrocyclic agents, which in both human and animal studies have been shown to be associated with lower levels of Gadolinium deposition, and detailed documentation of dosing. Most important, a patient should not be deprived of a well-indicated contrasted MR examination.
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high levels of Gadolinium deposition in the skin of a patient with normal renal function
Investigative Radiology, 2016Co-Authors: Donna R. Roberts, Scott Lindhorst, Cynthia T Welsh, Kenneth R Maravilla, Mary N Herring, Adam K Braun, Bruce H Thiers, Clay W DavisAbstract:OBJECTIVE The aim of this study was to assess Gadolinium deposition in the skin of a patient with normal renal function, based on estimated glomerular filtration rate values greater than 59 mL/min/1.73 m(2) after exposure to large cumulative doses of Gadolinium-based contrast agents (GBCAs). MATERIALS AND METHODS The patient underwent 61 contrasted brain MRI scans over the course of 11 years. Skin biopsies from the forearm and lower extremity were analyzed with inductively coupled plasma mass spectrometry (ICP-MS), laser ablation ICP-MS, and hydrophilic interaction liquid chromatography ICP-MS. RESULTS The ICP-MS demonstrated high levels of Gadolinium deposition (14.5 ± 0.4 μg/g), similar to previously reported Gadolinium levels within the skin of patients with nephrogenic systemic fibrosis. The laser ablation ICP-MS demonstrated deposition of Gadolinium within the deep layers of skin. Speciation analysis using hydrophilic interaction liquid chromatography ICP-MS demonstrated the presence of intact Gadolinium-chelate species, although most of the Gadolinium present could not be further characterized. Light microscopy demonstrated increased CD34 immunoreactivity in the connective tissue septations of the subcutaneous adipose tissue. The patient had no history of skin disorders and did not have a history of nephrogenic systemic fibrosis but did have severe joint contractures of unknown etiology. CONCLUSIONS Our results, in contradiction to published literature, suggest that in patients with normal renal function, exposure to GBCAs in extremely high cumulative doses can lead to significant Gadolinium deposition in the skin. This finding is in line with more recent reports of Gadolinium deposition in the brain of patients with normal renal function. Future studies are required to address possible clinical consequences of Gadolinium deposition in the skin, brain, and potentially other organs in patients with normal renal function. We recommend, in addition to following current US Food and Drug Administration and American College of Radiology guidelines based on estimated glomerular filtration rate values, that caution be used when administering large cumulative doses of GBCAs and that total cumulative dose of each agent administered is recorded in the patient's medical record.
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progressive increase of t1 signal intensity in the dentate nucleus and globus pallidus on unenhanced t1 weighted mr images in the pediatric brain exposed to multiple doses of Gadolinium contrast
Brain & Development, 2016Co-Authors: Donna R. Roberts, Kenton R HoldenAbstract:Recently, there have been reports of Gadolinium accumulation in the brain and bone of adult patients with normal renal function who have undergone multiple Gadolinium contrast administrations. This case report gives the first description of a pediatric patient who, following multiple contrasted MRI exams, demonstrated abnormal signal on unenhanced T1-weighted imaging involving the dentate nucleus and globus pallidus, a finding which has previously been shown to represent Gadolinium deposition in adults. The patient presented here had no history of intracranial pathology which would alter the blood brain barrier or abnormal renal function. The clinical significance of Gadolinium accumulation in the human body is currently unknown but is of concern, particularly in pediatric patients who have a lifetime to manifest any potential adverse consequences. Therefore, research is needed to address the clinical significance, if any, of Gadolinium deposition in the developing pediatric brain. Given these current uncertainties, clinicians should continue to use prudence in selecting pediatric patients to undergo contrasted MRI and in selecting the appropriate contrast agents to use.
Martin R Prince - One of the best experts on this subject based on the ideXlab platform.
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Gadolinium retention a research roadmap from the 2018 nih acr rsna workshop on Gadolinium chelates
Radiology, 2018Co-Authors: Robert J Mcdonald, Jeffrey C. Weinreb, Emanuel Kanal, Kenneth R Maravilla, Deborah Levine, Matthew S Davenport, James H Ellis, Paula Jacobs, Robert E Lenkinski, Martin R PrinceAbstract:Gadolinium-based contrast agents (GBCAs) have revolutionized MRI, enabling physicians to obtain crucial life-saving medical information that often cannot be obtained with other imaging modalities. Since initial approval in 1988, over 450 million intravenous GBCA doses have been administered worldwide, with an extremely favorable pharmacologic safety profile; however, recent information has raised new concerns over the safety of GBCAs. Mounting evidence has shown there is long-term retention of Gadolinium in human tissues. Further, a small subset of patients have attributed a constellation of symptoms to GBCA exposure, although the association of these symptoms with GBCA administration or Gadolinium retention has not been proven by scientific investigation. Despite evidence that macrocyclic GBCAs show less Gadolinium retention than linear GBCAs, the safety implications of Gadolinium retention are unknown. The mechanism and chemical forms of Gadolinium retention, as well as the biologic activity and clinical importance of these retained Gadolinium species, remain poorly understood and underscore the need for additional research. In February 2018, an international meeting was held in Bethesda, Md, at the National Institutes of Health to discuss the current literature and knowledge gaps about Gadolinium retention, to prioritize future research initiatives to better understand this phenomenon, and to foster collaborative standardized studies. The greatest priorities are to determine (a) if Gadolinium retention adversely affects the function of human tissues, (b) if retention is causally associated with short- or long-term clinical manifestations of disease, and (c) if vulnerable populations, such as children, are at greater risk for experiencing clinical disease. The purpose of the research roadmap is to highlight important information that is not known and to identify and prioritize needed research. ©RSNA, 2018 Online supplemental material is available for this article .
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the effects of time varying intravascular signal intensity and k space acquisition order on three dimensional mr angiography image quality
Journal of Magnetic Resonance Imaging, 1996Co-Authors: Jeffrey H Maki, Martin R Prince, Frank J Londy, Thomas L ChenevertAbstract:The optimum infusion timing and k-space ordering for obtaining Gadolinium-enhanced three-dimensional MR angiograms was determined through computer modeling using temporal contrast characteristics obtained from patient Gadolinium infusion data. The effects of bolus timing were evaluated by varying the relationship between peak intravascular Gadolinium concentration and the time at which the center of k space was acquired (tck) for sequential and centric acquisition techniques. Flow phantom experiments were performed to validate the theoretical computations. Gadolinium concentration at the time of central k-space acquisition determines intravascular signal intensity. Artifacts, including vessel broadening and edge ringing, depend on the order in which k space is collected and on how rapidly the Gadolinium concentration changes. Artifacts are greatest when the center of k space is acquired before the intravascular Gadolinium peak. Application of the optimal infusion timing results in preferential arterial enhancement with a minimum of artifacts in patients undergoing MR angiography.
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nephrotoxicity of high dose Gadolinium compared with iodinated contrast
Journal of Magnetic Resonance Imaging, 1996Co-Authors: Martin R Prince, Christina Arnoldus, Joan K FrisoliAbstract:To determine if high-dose Gadolinium chelates are less nephrotoxic than iodinated contrast. Records of 342 patients who had received high-dose Gadolinium (.2 to .4 mmol/kg) for magnetic resonance imaging were reviewed to identify patients who had also received iodinated contrast for radiographic examinations. Their clinical course and laboratory data were reviewed to identify changes in serum creatinine attributable to the contrast agents. In 64 patients, serum creatinine data were available pre and post both Gadolinium and iodinated contrast. The mean change in serum creatinine after Gadolinium in these 64 patients was −.07 mg/dL (−6 μmol/L). By comparison, the mean change in serum creatinine in the same patients after iodinated contrast was .35 mg/dL (+31 μmol/L) from 2.0 ± 1.4 to 2.3 ± 1.8 (P=.002). Eleven of the 64 patients had iodinated contrast-induced renal failure (.5 mg/dL or greater rise in serum creatinine); none had Gadolinium contrast-induced renal failure despite the high Gadolinium dose and high prevalence of underlying renal insufficiency. High-dose Gadolinium chelates are significantly less nephrotoxic than iodinated contrast.
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Gadolinium enhanced magnetic resonance angiography of abdominal aortic aneurysms
Journal of Vascular Surgery, 1995Co-Authors: Martin R Prince, Dasika L Narasimham, James C Stanley, Thomas W Wakefield, Louis M Messina, Gerald B Zelenock, William T Jacoby, Victoria M Marx, David M Williams, Kyung J ChoAbstract:Abstract Purpose: The objective of this study was to assess the usefulness of gadolinum-enhanced magnetic resonance angiography (MRA) for defining anatomic features relevant to performing aortic surgery for aneurysmal disease. Methods: Anatomic data defined by MRA, including abdominal aortic aneurysm (AAA) size and character, as well as the status of the celiac, mesenteric, renal, and iliac arteries, were correlated with angiography, ultrasonography, computed tomography, or operative data in 43 patients. Five MRA sequences were obtained in an hour-long examination optimized for aortoiliac, splanchnic, and renal artery imaging at 1.5 T in a body coil. Four of the sequences were performed during or after infusion of Gadolinium to improve image quality. Results: MRA correctly defined the maximum aneurysm diameter, as well as its proximal and distal extent in all patients. MRA detected 33 of 35 significant stenoses among 153 splanchnic, renal, or iliac branches examined (sensitivity = 94% and specificity=98%). MRA did not resolve the degree of aortic branch stenotic disease sufficiently to precisely grade its severity. MRA did not reliably define the status of the inferior mesenteric artery, lumbar arteries or internal iliac arteries. One ruptured AAA and one inflammatory AAA were correctly diagnosed by MRA. No patient had a contrast reaction or contrast-induced renal toxicity related to administration of Gadolinium. Conclusion: Gadolinium-enhanced MRA of AAA provides appropriate, essential anatomic information for aortic reconstructive surgery in a 1-hour examination devoid of contrast-related renal toxicity or catheterization-related complications attending conventional arteriography. (J VASC SURG 1995;21:656-69.)
Marcelo Souto Nacif - One of the best experts on this subject based on the ideXlab platform.
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Gadolinium enhanced cardiovascular magnetic resonance administered dose in relationship to united states food and drug administration fda guidelines
Journal of Cardiovascular Magnetic Resonance, 2012Co-Authors: Marcelo Souto Nacif, Andrew E Arai, Joao A C Lima, David A BluemkeAbstract:Myocardial late Gadolinium enhancement was originally validated using higher than label-recommended doses of Gadolinium chelate. The objective of this study was to evaluate available evidence for various Gadolinium dosing regimens used for CMR. The relationship of Gadolinium dose warnings (due to nephrogenic systemic fibrosis) announced in 2008 to Gadolinium dosing regimens was also examined. We conducted a meta-analysis of peer reviewed publications from January, 2004 to December, 2010. Major subject search headings (MeSh) terms from the National Library of Medicine's PubMed were: contrast media, Gadolinium, heart, magnetic resonance imaging; searches were limited to human studies with abstracts published in English. Case reports, review articles, editorials, MRA related papers and all reports that did not indicate Gadolinium type or weight-based dose were excluded. For all included references, full text was available to determine the total administered Gadolinium dose on a per kg basis. Average and median dose values were weighted by the number of subjects in each study. 399 publications were identified in PubMed; 233 studies matched the inclusion criteria, encompassing 19,934 patients with mean age 54.2 ± 11.4 (range 9.3 to 76 years). 34 trials were related to perfusion testing and 199 to myocardial late Gadolinium enhancement. In 2004, the weighted-median and weighted-mean contrast dose were 0.15 and 0.16 ± 0.06 mmol/kg, respectively. Median contrast doses for 2005-2010 were: 0.2 mmol/kg for all years, respectively. Mean contrast doses for the years 2005-2010 were: 0.19 ± 0.03, 0.18 ± 0.04, 0.18 ± 0.10, 0.18 ± 0.03, 0.18 ± 0.04 and 0.18 ± 0.04 mmol/kg, respectively (p for trend, NS). Gadopentetate dimeglumine was the most frequent Gadolinium type [114 (48.9%) studies]. No change in mean Gadolinium dose was present before, versus after the Food and Drug Administration (FDA) black box warning (p > 0.05). Three multi-center dose ranging trials have been published for cardiac MRI applications. CMR studies in the peer-reviewed published literature routinely use higher Gadolinium doses than regulatory agencies indicated in the package leaflet. Clinical trials should be supported to determine the appropriate doses of Gadolinium for CMR studies.
