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Accuracy of ocular axial length measurement with MRI
E I Akduman1, R E Nacke, P M Leiva
1Department of Radiology, Saint Louis University, St. Louis, Mo. 63104, USA.
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.
