High-Resolution Magnetic Resonance Imaging of the Extraocular Muscles and Nerves Demonstrates Various Etiologies of Third Nerve Palsy

Abstract

Purpose-The etiology of third nerve palsy is usually diagnosed by history, motility examination, and presence of lid and pupil involvement, as well as cranial and vascular imaging. We used highresolution magnetic resonance imaging (hrMRI) of the oculomotor nerve and affected extraocular muscles (EOMs) to investigate oculomotor palsy.Design-Prospective, noncomparative, observational case series in an academic referral setting.Methods-Twelve patients with non-aneurysmal oculomotor palsy of duration 0.75 to 252 months were studied. In the orbit and along the intracranial oculomotor nerve, hrMRI at 1-2mm thickness was performed. Coronal plane images of each orbit were obtained in multiple, controlled gaze positions. Structural abnormalities of the oculomotor nerve and associated changes in EOM volume and contractility were evaluated.Results-Cases were categorized as tumor-related, congenital, diabetic, traumatic, and idiopathic according to clinical characteristics and hrMRI findings. Reduction of volume and contractility of affected EOMs were noted in six patients; however, there was no significant EOMs atrophy in two cases with diabetic oculomotor palsy, and four cases with aberrant regeneration. hrMRI demonstrated the oculomotor nerve at the midbrain and at EOMs in all cases, and in two case with previous normal neuroimaging elsewhere demonstrated contrast-enhancing tumors on the oculomotor nerve. One Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptAm J Ophthalmol. Author manuscript; available in PMC 2008 February 1. Conclusions-hrMRI provides valuable information in patients with oculomotor palsy, such as structural abnormalities of the orbit and oculomotor nerve, and atrophy and diminished contractility of innervated EOMs. This information could be helpful in diagnosis and management of oculomotor palsy.

A Challenging Case: Monocular Elevation Deficiency or Oculomotor Synknesia?

“…Erişkinlerde en sık anevrizma, mikrovasküler hastalıklar ve travma nedeni ile ortaya çıkarken, çocuklarda doğumsal sebepler, travma ve inflamasyon başta gelen sebeplerdir. 6 Total okülomotor sinir felcinde üst rektus, alt rektus ve alt oblik kas vertikal hareketlerinde hiç addüksiyon görülmez iken kısmi okülomotor sinir felci ya da parezisi kısıtlı addüksiyon ve vertikal hareketler, normal ya da dilate ama ışığa yanıt veren pupilla ile normal ya da düşük göz kapağı ile karakterizedir. 7 Pupilla tutulumu erişkinlerde kompresif patolojilerin iskemik olanlardan ayırt edilmesine yararken, çocuklarda pupillanın korunmuş olması kraniyal görüntülemenin ertelenmesine kesinlikle neden olmamalıdır.…”

“…Literatürde Kau ve ark.nın bir çalışma-sında kullanılan yüksek çözünürlüklü manyetik rezonans görüntüleme ile standart çekim teknikleri ile saptanamayan patolojilerin ortaya çıkarıla-bileceği bildirilmiştir. 6 Olgunun ailesinden çok güvenilir olmamakla birlikte bir düşme öyküsü bilgisini aldıktan sonra değerlendirdiğimiz olgunun kısmi III. kraniyal sinir felci sonrası gelişen bir okülomotor sinkinezis tablosu olduğu düşünülmüştür.…”

MR Imaging of Congenital or Developmental Neuropathic Strabismus: Common and Uncommon Findings

“…Two patients with CNIII hypoplasia had hypoplasia of the medial rectus and/or the inferior rectus, suggesting a localized defect of the CNIII inferior branch innervating the associated EOMs. 1,11 Another patient with bilateral CNIII hypoplasia, combined with CNVI aplasia, had hypoplasia of the superior rectus and the medial rectus bilaterally, possibly reflecting a similar type of localized defects at the CNIII branches.…”

“…MR imaging studies of congenital or developmental neuropathic strabismus have been sporadically conducted, but most of these studies focused on the abnormalities of individual ocular motor nerves and EOMs. [1][2][3][4][5][6][7][8][9][10] To our knowledge, only Demer et al 11 and Jiao et al 12 conducted MR imaging studies to investigate the various etiologies of congenital or developmental neuropathic strabismus, including abnormalities of ocular motor nerves and EOMs. A population-based study 13 reported that CNIV palsy occurred with the highest frequency in patients with pediatric neuropathic strabismus.…”

Congenital innervation dysgenesis syndrome (CID)/congenital cranial dysinnervation disorders (CCDDs)

“…72 Such changes included absence or hypoplasia of various oculo-motor nerves, hypoplasia and reduction in the size of the EOMs and even bony orbital changes. [73][74][75][76] Congenital fibrosis syndrome of the EOM Assaf 4,5 documented neurological findings in CFEOM patients using the CT and MRI scans. In his study of eight patients with CFEOM, in one case the CT-scan indicated agenesis of superior rectus in both eyes.…”