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W.A. Lagreze, A. Lazzaro, M. Weigel, T. Bley; High Resolution MRI of the Optic Nerve: Delineation From Cerebrospinal Fluid and Changes of Nerve Diameter During Abduction . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4278.
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© ARVO (1962-2015); The Authors (2016-present)
To present a novel MRI technique of noninvasive imaging of theoptic nerve (ON) and its sheath in vivo and to quantify itsdiameters.
The right ON of 20 healthy volunteers (age 22–39, mean25) was investigated. MRI was performed on a 3T scanner usingan 8 channel phased–array head coil. A fast T2 weightedaxial and sagittal TSE sequence were used for planning (TR/TE= 4000/123 ms, spatial resolution = 0.41 x 0.47 mm, slth = 5mm, 7 slices, ETL = 25, Half Fourier reconstruction, TA = 1:06min). The ON diameter was quantified via a modified Half FourierSingle Shot Multi Spin Echo (HASTE) sequence acquired perpendicularto the optic nerve orientation (TR/TE = 5000/146 ms, spatialresolution = 0.45 x 0.50 mm, slth = 3 mm, TA = 15 sec, shortrf pulses). Diameters were measured directly retrobulbar, inthe mid, and in the posterior part of the ON. Both, localizerTSE and HASTE sequences were acquired twice with the volunteerlooking straight ahead and in 30° abduction.
The ON thins out from anterior to posterior as well as duringside gaze. The cerebrospinal fluid (CSF) sheath could be clearlydepicted along the whole ON (figure). The table shows the diametersof the ON in straight gaze and abduction.
HASTE sequences with short rf pulses provide very high contrastbetween the ON and CSF. They could verify the expected thinningof the ON during abduction caused by its extension. This novelMRI technique might be useful in patients with intracranialhypertension and optic nerve diseases.
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