title: Magnetic resonance compatibility of intraocular lenses measured at 7 Tesla.
abstract: OBJECTIVE
  To determine whether intraocular lenses (IOLs) are compatible with magnetic resonance imaging (MRI) at a magnetic field strength of 7 Tesla, the highest field strength at which clinical MRI scans are performed.
  
  
  METHODS
  A set of 23 intraocular lenses was selected based on the presence of dyes and metals and different geometric shapes. MR compatibility was evaluated in a high-field 7-Tesla MRI scanner according to the American Standard Test Method (ASTM). The magnetically induced displacement was measured via the angular deflection method. The degree of magnetic susceptibility artifact formation was evaluated by positioning the IOLs in a phantom gel for scanning, using a three-dimensional gradient echo (GRE) sequence. All images were visually inspected to determine the spatial extent of any signal voids. Fiber-optic temperature probes were deployed to measure radio-frequency (RF) heating using a GRE sequence with powers 10 times higher than clinical settings.
  
  
  RESULTS
  No significant displacement was detected with any of the tested IOLs. A significant magnetic susceptibility artifact was caused by the small platinum component of the Worst Platinum Clip IOL. None of the other 22 IOLs caused measurable susceptibility artifacts. Measurements on RF-induced heating showed no significant temperature rise (<0.25°C) of the tested IOLs.
  
  
  CONCLUSIONS
  MRI did not induce movement or RF heating of any of the IOLs. We conclude that all the tested intraocular lenses are considered safe for MRI up to and including 7 Tesla. One IOL, the Worst Platinum Clip IOL, caused a significant imaging artifact.
authors.affiliation: Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands. g.a.van_rijn@lumc.nl
authors.forename: Gwyneth A
authors.initials: GA
authors.lastname: van Rijn
authors.forename: Jurgen E M
authors.initials: JE
authors.lastname: Mourik
authors.forename: Wouter M
authors.initials: WM
authors.lastname: Teeuwisse
authors.forename: Gregorius P M
authors.initials: GP
authors.lastname: Luyten
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Webb
mesh_terms: D016477:Artifacts; D019544:Equipment Failure Analysis; D007910:Lenses, Intraocular; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008670:Metals; D019047:Phantoms, Imaging; D011475:Prosthesis Failure
chemical_list: D008670:Metals