title: Relative diffusion of paramagnetic metal complexes of MRI contrast agents in an isotropic hydrogel medium.
abstract: The observation of molecular diffusion by means of magnetic resonance imaging (MRI) is significant in the evaluation of the metabolic activity of living tissues. Series of MRI examinations were conducted on a diffusion model to study the behaviour of the diffusion process of different-molecular-weight (MW) paramagnetic MRI contrast agents in an isotropic agar hydrogel medium. The model consisted of a solidified 1 % agar gel with an initial concentration of 0.5 mmol/L contrast solution layered on top of the gel. The diffusion process was monitored at pre-determined time intervals of immediately, 1, 6, 9, 23, and 48 h after introduction of the contrast agents onto the agar gel with a T1-weighted spin-echo (SE) pulse sequence. Three types of paramagnetic contrast agents, Gd-DTPA with a MW of 547.57 g/mol, Prohance with a MW of 558.69 g/mol and MnCl2with a MW of 125.84 g/mol, resulted in an approximate average diffusional displacement ratio of 1:1:2 per hour, respectively, within 48 h of the experiment. Therefore, the results of this study supported the hypothesis that the rate of the diffusion process of MRI contrast agents in the agar hydrogel medium is inversely related to their MWs. However, more repetitions are necessary under various types of experimental conditions and also with various types of contrast media of different MWs for further confirmation and validation of these results.
authors.affiliation: Graduate School of Advanced Integration Science, Chiba University, 1-33, Yayoicho, Inage Ward, Chiba-shi, Chiba, 263-8522, Japan. bsw888@gmail.com.|Department of Radiography/Radiotherapy, Faculty of Allied Health Sciences, University of Peradeniya, Peradeniya, 20400, Sri Lanka. bsw888@gmail.com.
authors.forename: Bimali Sanjeevani
authors.identifier: http://orcid.org/0000-0003-0843-6389
authors.initials: BS
authors.lastname: Weerakoon
authors.affiliation: Center for Frontier Medical Engineering, Chiba University, 1-33, Yayoicho, Inage Ward, Chiba-shi, Chiba, 263-8522, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Osuga
mesh_terms: D002712:Chlorides / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry*; D004058:Diffusion; D005682:Gadolinium / Q000737:chemistry; D019786:Gadolinium DTPA / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000737:chemistry; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D008279:Magnetic Resonance Imaging; D059346:Magnets / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D008962:Models, Theoretical; D008970:Molecular Weight; D009942:Organometallic Compounds / Q000737:chemistry; D019047:Phantoms, Imaging
chemical_list: D002712:Chlorides; D003287:Contrast Media; D006571:Heterocyclic Compounds; D017895:Manganese Compounds; D008670:Metals; D009942:Organometallic Compounds; C062402:gadoteridol; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D005682:Gadolinium; D019786:Gadolinium DTPA; C025340:manganese chloride
keywords: Diffusion; Isotropic hydrogel medium; Molecular weight; Paramagnetic contrast agents