title: Positive visualization of implanted devices with susceptibility gradient mapping using the original resolution.
abstract: In magnetic resonance imaging, implantable devices are usually visualized with a negative contrast. Recently, positive contrast techniques have been proposed, such as susceptibility gradient mapping (SGM). However, SGM reduces the spatial resolution making positive visualization of small structures difficult. Here, a development of SGM using the original resolution (SUMO) is presented. For this, a filter is applied in k-space and the signal amplitude is analyzed in the image domain to determine quantitatively the susceptibility gradient for each pixel. It is shown in simulations and experiments that SUMO results in a better visualization of small structures in comparison to SGM. SUMO is applied to patient datasets for visualization of stent and prostate brachytherapy seeds. In addition, SUMO also provides quantitative information about the number of prostate brachytherapy seeds. The method might be extended to application for visualization of other interventional devices, and, like SGM, it might also be used to visualize magnetically labelled cells.
authors.affiliation: Division of Imaging Sciences, King's College London, St Thomas' Hospital, Westminster Bridge Road, London, United Kingdom. gopal.varma@kcl.ac.uk
authors.forename: Gopal
authors.initials: G
authors.lastname: Varma
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Clough
authors.forename: Peter
authors.initials: P
authors.lastname: Acher
authors.forename: Julien
authors.initials: J
authors.lastname: Sénégas
authors.forename: Hannes
authors.initials: H
authors.lastname: Dahnke
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Keevil
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
mesh_terms: D000497:Alloys; D000784:Aortic Dissection / Q000601:surgery*; D017545:Aortic Aneurysm, Thoracic / Q000601:surgery*; D001918:Brachytherapy / Q000295:instrumentation*; D003198:Computer Simulation; D005682:Gadolinium; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008962:Models, Theoretical; D009942:Organometallic Compounds; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D012984:Software; D015607:Stents
chemical_list: D000497:Alloys; D009942:Organometallic Compounds; C013616:nitinol; D005682:Gadolinium; C109932:gadofosveset trisodium