title: Accuracy of ocular axial length measurement with MRI.
abstract: BACKGROUND
  This study assessed axial length measurements taken with MRI compared to A-scan ultrasonography for use in silicone-filled eyes with cataracts.
  
  
  METHODS
  This study was a double-blinded prospective comparison study of axial length measurements made by MRI and A-scan ultrasonography. MRI scans of 20 patients undergoing MRI were reviewed to determine axial length. Standard A-scan measurements of axial length were also obtained. Axial length measurements by MRI were compared to A-scan ultrasonography measurements.
  
  
  RESULTS
  In 36 eyes, an MRI scan was obtained in the correct plane to measure the axial length. The axial length measured by MRI was on average 0.18 +/- 0.29 mm longer (range -0.41 to +0.7 mm) than the axial length measured by A-scan, for a refractive error average of +0.28 +/- 0.58 D (SD), and a range of -1.06 to +1.52 D.
  
  
  CONCLUSIONS
  Axial length measurements with MRI match reliably with axial lengths measured by A-scan ultrasonography.
authors.affiliation: Department of Radiology, Saint Louis University, St. Louis, Mo. 63104, USA.
authors.forename: E I
authors.initials: EI
authors.lastname: Akduman
authors.forename: R E
authors.initials: RE
authors.lastname: Nacke
authors.forename: P M
authors.initials: PM
authors.lastname: Leiva
authors.forename: L
authors.initials: L
authors.lastname: Akduman
mesh_terms: D002386:Cataract / Q000473:pathology*; D004311:Double-Blind Method; D005123:Eye / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009929:Organ Size; D015203:Reproducibility of Results