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Advances in and Uses of Contrast Agents for Spectral Photon Counting Computed Tomography
Published in Katsuyuki Taguchi, Ira Blevis, Krzysztof Iniewski, Spectral, Photon Counting Computed Tomography, 2020
Johoon Kim, Pratap C. Naha, Peter B. Noël, David P. Cormode
The K-edge energy of gadolinium is also well-separated from K-edge energy of iodine, which can allow dual contrast imaging of gadolinium and iodine. Dangelmaier et al. investigated the feasibility of differentiating endoleaks from intra-aneurysmatic calcifications after repair in a single CT scan.63 In their phantom model, a stent-lined compartment that represented an aortic aneurysm was filled with both gadolinium chelate (gadopentetic acid dimeglumine) and iodine. Several compartments adjacent to the first were filled with either iodine representing an endoleak in the arterial phase, gadolinium representing a leak in the venous or delayed phase, or calcium chloride representing calcifications. These different compartments of similar attenuation values could be easily differentiated in the material-specific images of gadolinium, iodine, and calcium that were generated in the study.
Paramagnetic Contrast Agents
Published in Michel M. J. Modo, Jeff W. M. Bulte, Molecular and Cellular MR Imaging, 2007
Silvio Aime, Zsolt Baranyai, Eliana Gianolio, Terreno Enzo
Other Gd delivery systems include the Gd-chitosan nanoparticles (430 nm) containing 9.3% (w/w) of Gd(III),30 the distearylamide gadopentetic acid microcapsules (106 to 149 μM) containing 5.13% (w/w) of Gd(III),31 the gadolinium hexanedione (GdH) nanoparticles containing 2.5 mg/ml of GdH,32 and the Gd-incorporated lipid nanoemulsions (100 nm) containing 3 mg/ml of Gd(III).33
Early stage T1-weighted perfusion magnetic resonance imaging: a factor that predicts local control response in patients with meningioma who underwent gamma-knife radiosurgery
Published in Neurological Research, 2022
Anas Abdallah, Mehmet Hakan Seyithanoğlu, Meliha Gündağ Papaker, Ayşe Aralaşmak, Selçuk Yapar, Gökhan Baloğlu
MRI scanning with a head coil on a 1.5 Tesla system (Avanto; Siemens Medical System, Erlangen, Germany) was performed. First, non-contrast MR images were taken. Next, DCE-MR and DSC-MR images (Ktrans) were taken, and with the additional second contrast injection, T2-weighted images were taken. After the completion of the MR perfusion images, conventional contrast-enhanced MR images were recorded. Since permeability (T1 perfusion on DCE-MRI) and perfusion MRI (T2 perfusion on DSC-MRI) were performed together, a single dose (0.1 mmol/kg) was divided into two equal doses. After each dose, a minimum of 10 ml of physiological saline solution was applied. The contrast substance gadopentetic acid dimeglumine (Emaray ®, Biem, Ankara, Turkey) was applied to all patients using automatic injection with a rate of 2 mL/s for 0.05 mmol/kg in DCE-MRI and a rate of 5 mL/s for 0.05 mmol/kg in DSC-MRI.
Periprocedural risk factors for incomplete radiofrequency ablation of liver metastases from colorectal cancer: a single-center retrospective analysis
Published in International Journal of Hyperthermia, 2021
Hongjie Fan, Xiaoyan Wang, Jiali Qu, Wei Lu, Zhenzhu Pang, Tingting Shao, Jingya Xia, Huiyang Wang, Guangyao Li, Yanhua Zhang, Jihong Sun, Xiaoming Yang
The MR examinations (GE Signa HDx 3.0 T, Boston, MA, USA) of the liver or upper abdomen were performed within 1 week before RFA and included nonenhanced and DCE T1-weighted imaging, T2-weighted imaging, and diffusion-weighted imaging (DWI) to determine the number, size, and location of the tumor, as well as adjacent blood vessels, tissues, and organs. The MR scan parameters are shown in Supplementary Table S1. The contrast agent gadopentetic acid dimeglumine solution (20 ml: 9.38 g; Beilu Pharmaceutical Co., Ltd., Beijing, China) was used for DCE MR examination with an injection speed of 3 ml/s. Then, 20 ml of normal saline was used for flushing, and images of the arterial phase, portal phase, and equilibrium phase were obtained by scanning at intervals of 30, 60, and 90 s, respectively. The acquisition parameters of DWI were as follows: field of view, 400 × 400; matrix, 320 × 224; section thickness, 6; B value, 0/800. The collected DWI images were post-processed (b800-b0), and the apparent diffusion coefficient (ADC) map was calculated and generated using the Picture Archiving and Communication Systems, and then, the ADC value was obtained by delineating the area of interest of the lesion. Laboratory tests, such as coagulation function, liver function, heart function, blood routine, renal function, tumor markers (carbohydrate antigen [CA]-125, CA19-9, carcinoembryonic antigen [CEA]), and electrolyte levels, were performed to identify possible contraindications.
Gadolinium-based contrast agents – what is the evidence for ‘gadolinium deposition disease’ and the use of chelation therapy?
Published in Clinical Toxicology, 2020
Kerry A. Layne, David M. Wood, Paul I. Dargan
Recent radiological analyses and post mortem studies, however, have suggested that exposure to gadolinium-based contrast agents may result in gadolinium deposition in human brain and bone tissue in those patients with normal renal function [7–18]. In September 2017, the United States Food and Drug Administration (FDA) convened a Medical Imaging Drugs Advisory Committee meeting to review the emerging data related to gadolinium deposition in the brain and other body organs in patients with normal renal function. The team concluded that whilst current evidence shows that gadolinium is retained in human tissues post-exposure to gadolinium-based contrast agents, “for all or almost all of the millions of patients with normal renal function who have benefitted diagnostically from these drugs since 1988, the range of post-GBCA [gadolinium-based contrast agents] gadolinium retention probably falls below exposure thresholds that could induce grossly observable subacute/chronic adverse reactions” [6]. Subsequently, the UK Medicines and Healthcare products Regulatory Agency (MHRA) and the FDA released new guidance in December 2017 advising healthcare professionals to aim to minimise requests for gadolinium-enhanced MRI scans unless diagnostic information is essential, with the MHRA also suspending the licences for the linear agents, gadodiamide (Omniscan) and intravenous gadopentetic acid (Magnevist) [19,20]. The European Medicines Agency similarly issued recommendations to restrict the use of some linear gadolinium agents used in MRI body scans and to suspend the authorisations of others [21].