Comparion of Orbital Magnetic Reonance Imaging in Duane yndrome and Abducen Paly Original Reearch Article

Purpoe To help reolve the clinical ambiguity between Duane yndrome with evere abduction deficit and abducen paly, we performed orbital magnetic reonance imaging (MRI) to qualify abnormalitie of the lateral rectu (LR) mucle in thee entitie. Deign Propective obervational cae erie. Method Orbital MRI wa performed in 13 ubject with Duane yndrome (19 eye), 10 ubject with chronic abducen paly (10 eye), and 10 orthotropic control ubject (18 eye). High-reolution, urface coil, T1-weighted MRI wa ued to obtain contiguou, 2-mm thick quai-coronal image of the orbit in central gaze. Digital image analyi wa ued to quantify cro-ectional area of the ipileional and contraleional LR to provide comparion with control meaurement. Reult Mean maximum LR cro-ectional area in Duane yndrome wa tatitically imilar to control (P = .454) and contraleional LR cro-ectional area (P = .227). However, in chronic abducen paly, mean maximum ipileional LR cro-ectional area wa markedly maller than contraleional (P = .003) and control cro-ectional area (P < .0001), a well a maller than the LR in Duane yndrome (P= .0017). Concluion The LR mucle in abducen paly exhibit profound atrophy. The paring of the LR in Duane yndrome from denervation atrophy depite abence of normal abducen innervation ugget exitence of alternative LR innervation. High-reolution MRI can noninvaively demontrate LR mucle ize and ditinguih Duane yndrome from chronic abducen paly in uncertain cae.