The Efficacy of Imaging Diagnosis in Oculomotor Abnormalities

Seung Hyun Lee; Hwan Heo; Sang Woo Park

doi:10.3341/jkos.2009.50.2.260

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Lee, Heo, and Park: The Efficacy of Imaging Diagnosis in Oculomotor Abnormalities

Original Article

J Korean Ophthalmol Soc 2009;50(2):260-268.

Published online: 3 January 2009

DOI: https://doi.org/10.3341/jkos.2009.50.2.260

The Efficacy of Imaging Diagnosis in Oculomotor Abnormalities

Seung Hyun Lee, MD, Hwan Heo, MD, Sang Woo Park, MD, PhD

Department of Ophthalmology, Chonnam National University Medical School, Gwangju, Korea

Address reprint requests to Sang-Woo Park, MD Department of Ophthalmology, Chonnam National University Medical School & Hospital #8 Hak-dong, Dong-gu, Gwang-ju 501-757, Korea Tel: 82-62-220-6743, Fax: 82-62-227-1642, E-mail: exo70@naver.com

Received 14 April 2008 Accepted 16 September 2008

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To evaluate the usefulness of imaging diagnosis in patients with atypical oculomotor abnormalities and paralytic strabismus.

Methods

The magnetic resonance imaging (MRI) or computed tomography (CT) of 3 patients with atypical Y pattern vertical incomitance and medial rectus (MR) paresis after MR impingement reduction and A pattern vertical incomitance were analyzed. High-resolution, surface coil MRI was used to obtain sets of contiguous, 2-mm thick quasi-coronal images in 9-cardinal gaze directions. Digital image analysis was used to evaluate the results.

Results

MRI revealed lateral displacement of the superior rectus (SR) and inferior displacement of the lateral rectus (LR) during upper temporal gaze and inferior displacement of the LR during lateral gaze in patients with Y pattern vertical incomitance. In patients with MR paresis, the maximal surface area of MR cross section is in the image plane 10 mm posterior from the orbital center at primary gaze. The maximal surface area of MR cross section is in the image plane 22 mm posterior from the orbital center during medial gaze. Quasi-coronal images show that contraction tends to cause the plane of maximum cross-section to move posteriorly. Surgical treatment was avoided and observational treatment maintained. There is incyclotorsion of both extraocular muscles in patients with A pattern vertical incomitance and upslanted palpebral fissure.

Conclusions

Imaging diagnosis of pulley position and rectus muscle contractility is helpful for determining accurate diagnosis and treatment methods at atypical oculomotor abnormalities and paralytic strabismus.

Keywords: Extraocular muscles, Magnetic resonance imaging, Strabismus

References

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Figure 1.

(A) Preoperative 9-cardinal photograph shows 40PD of Y-pattern exotropia. (B) Postoperative 9-cardinal photograph shows no improvement of Y-pattern exotropia (postoperative 3 months). (C) Postoperative 9-cardinal photograph shows improvement of Y-pattern vertical incomitance (second postoperative 3 months).

Figure 2.

(A) Preoperative 9-cardinal photograph shows medial rectus motility limitation of the right eye. (B) Postoperative 9-cardinal photograph shows orthotropia in primary position and no motility restriction (postoperative 4 months).

Figure 3.

(A) Preoperative 9-cardinal photograph shows 25PD of A-pattern exotropia and 25PD of left hypertropia. (B) Orbital MRI image shows incyclotorsion of both extraocular muscles and mucocele involved both the frontal and ethmoid sinuses.

Figure 4.

(A, B) Diagram of 4 rectus muscles position in upper lateral gaze, upgaze, upper medial gaze and primary position. (C, D) Diagram of 4 rectus muscles position in lateral, medial gaze and primary position. (A) Note the lateral displacement of SR (red arrow) and inferior displacement of LR (red arrow) in upper lateral gaze (right eye). (B) Note the minimal rectus muscles shift during upgaze (left eye). (C) Note the inferior displacement of LR (red arrow) in lateral gaze (right eye). (D) Note the minimal rectus muscle pulleys shift during horizontal gaze (left eye). PP=primary position; UCG=upper central gaze; UMG=upper medial gaze; ULG=upper lateral gaze; MG= medial gaze; LG=lateral gaze.

Figure 5.

Quasi-coronal images of right orbit in primary position and medial gaze in a patient, who underwent medial rectus impingement reduction surgery (postoperative 2 months). (A) 10 mm posterior to the orbital center at primary gaze. (B) 10 mm posterior to the orbital center at medial gaze. (C) 22 mm posterior from the orbital center at primary gaze. (D) 22 mm posterior from the orbital center in medial gaze. At primary position the maximal surface area or medial rectus (MR) cross section is in image plane 10 mm posterior from the orbital center. In medial gaze the maximal surface area of MR cross section is in image plane 22 mm from the orbital center. Quasi-coronal images show that contraction tends to cause the planes of maximum cross-section to move posteriorly.

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