title: Coil optimization for low-field MRI: a dedicated process for small animal preclinical studies.
abstract: We demonstrate a method for the fast in vivo quantification of small volumes, down to 25 µL, using low-field magnetic resonance imaging (MRI) coils. The coils were designed so as to maximize the signal-to-noise ratio (SNR) in the images. For this we developed an analytical model for describing the variations of the SNR with coil design and with size/shape suited to the object under observation. Based on the conclusions drawn from the model, the coil parameters were chosen in order to reach an SNR close to the maximum. For the validation of the model, coils were finally characterized in terms of quality factor using saline phantoms. The coil design procedure is illustrated here with two examples: first, the quantification of about 200 µL of intradermal injected gel on rabbits with a single loop surface coil and second, the imaging of the intervertebral disks in rat tails using a small volume coil to detect possible lesions. Such studies would not have been feasible for the clinical low-field MRI system at our disposal using any of the commercially available medium-sized manufactured coils. As a result of this simple optimization procedure, a wide range of applications is accessible even at low magnetic fields, leading to new opportunities for low-cost, though efficient, preclinical studies.
authors.affiliation: Université de Lyon, CREATIS; CNRS UMR 5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Villeurbanne, France Cirma, Marcy l'Etoile, France.
authors.forename: T
authors.initials: T
authors.lastname: Feuillet
authors.affiliation: Cirma, Marcy l'Etoile, France.
authors.forename: M-J
authors.initials: MJ
authors.lastname: Seurin
authors.affiliation: Institut Claude Bourgelat, VetAgro Sup, Campus Vétérinaire de Lyon, Marcy l'Etoile, France.
authors.forename: O
authors.initials: O
authors.lastname: Leveneur
authors.affiliation: Université de Lyon, VetAgro Sup, Campus Vétérinaire de Lyon, Marcy l'Etoile, France.
authors.forename: E
authors.initials: E
authors.lastname: Viguier
authors.affiliation: Université de Lyon, CREATIS; CNRS UMR 5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Villeurbanne, France olivier.beuf@univ-lyon1.fr.
authors.forename: O
authors.initials: O
authors.lastname: Beuf
mesh_terms: D000818:Animals; D005260:Female; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011817:Rabbits
keywords: coil optimization; low-field MRI; non-invasive; sacrifices reduction; small animal