MRI measurements of the normal pediatric optic nerve pathway

Abstract

The purpose of this work is to establish a reference scale of optic nerve pathway measurements in pediatric patients according to age using MRI. Optic nerve pathway measurements were retrospectively analyzed using an orbits equivalent sequence on brain MRI scans of 137 pediatric patients (72 male, 65 female, average age = 7.7 years, standard deviation = 5.3). The examinations were performed on a 1.5-T or 3-T Siemens MR system using routine imaging protocols. Measurements include diameters of the orbital optic nerves (OON), prechiasmatic optic nerves (PON), optic tracts (OT), and optic chiasm (OC). Measurements were performed manually by 2 neuroradiologists, using post-processing software. Patients were stratified into five age groups for measurement analyses: (I) 0-1.49 years, (II) 1.5-2.99 years, (III) 3-5.99 years, (IV) 6-11.99 years, and (V) 12-18 years. The observed value range of OON mean diameter was 2.7 mm (Interquartile range (IQR) = 2.4-2.9), PON was 3.2 mm (IQR = 3.05-3.5), OT 2.6 mm (IQR = 2-2.9). A strong positive correlation was established between age and mean diameter of OON (r = 0.73, p < .001), PON (r = 0.59, p < .001), and OT (r = 0.72, p < .001). A significant difference in mean OON diameters was found between age groups I-II (d = 0.3, p = .01), II-III (d = 0.5, p < .001), III-IV (d = 0.5, p < .001) followed by a plateau between IV-V (d = 0.l0, p = .19). OON/OT ratio maintained a steady mean value 1 (IQR = 0.93-1.1) regardless of age (p = .7). The diameter of optic pathways was found to increase as a function of age with consistent positive correlation between nerve and tract for all ages.

Measurement of normal optic nerve for Sudanese pediatric using magnetic resonance imaging

“…3 Also this study agreement the study done by Maresky et al found that a strong positive correlation was established between age and mean diameter of OON and the measurement of OON increase with age. 2 The diameter of ON slightly more in females than the males with no significant difference, this result agreement with study done by Al-Haddad et al whom found that optic nerve diameter not differ in both sexes.…”

“…Various pathologies affecting the ONs, isolated or associated with other intracranial abnormalities, measuring the optic pathway is important and aid in the diagnosis of many pathologies, congenital malformations, and acquired diseases are affect the ON and associated structures, increased in ON diameter is seen in increased idiopathic intracranial hypertension, small optic pathways can be indicative of several disorders, with the most severe of them being septo-optic dysplasia and ON hypoplasia, a large optic pathway may be indicative of glioma, meningioma, lymphoma, or hemorrhage. 1,2 MRI an outstanding depiction of the complicated anatomy of the ON because of its determinizations of tissue contrast without using ionizing radiation, it was a higher delineation of the whole visible pathway and correct assessment of related intracranial pathologies. 3 Many studies found that there was an importance of measuring the ONs to make a standard scale for evaluation of ON abnormalities.…”

“…3 Many studies found that there was an importance of measuring the ONs to make a standard scale for evaluation of ON abnormalities. 2,3,5 There is no Sudanese comprehensive anthropometric study on normal measurement of normal ON and therefore undertake this study to measure the normal ON in Sudanese paediatric population.…”

Increasing the Accuracy of Optic Nerve Measurement Using 3D Volumetry

“…1,3 Volumetry has been widely validated in neurologic and orbital studies and is reproducible. 1,4 Finally, we agree with the authors that there is a need to establish a standardized method for the measurement of the optic nerve on MR imaging, but we believe that volumetric measurements should be made including the entire volume of the optic nerve starting from the papilla and ending at the point of convergence of the extraocular muscles at the tendinous ring of the orbital apex, 1 or ending at the chiasma, to provide accurate and reproducible measurements.…”

The Evaluation of Optic Nerves Using 7 Tesla “Silent” Zero Echo Time Imaging in Patients with Leber’s Hereditary Optic Neuropathy with or without Idebenone Treatment

“…Optic nerve imaging protocols usually include multi-slice T1 and T2-weighted scans in both axial and coronal orientations, as well as post-contrast scans [2,3]. Partial volume effects in two-dimensional sequences, however, often compromise accurate depiction of the optic nerves along their full extent.…”