Background: Magnetic resonance imaging (MRI) has not yet been established systematically to detect structural muscular changes after facial nerve lesion. The purpose of this pilot study was to investigate quantitative assessment of MRI muscle volume data for facial muscles.
Methods: Ten healthy subjects and 5 patients with facial palsy were recruited. Using manual or semiautomatic segmentation of 3T MRI, volume measurements were performed for the frontal, procerus, risorius, corrugator supercilii, orbicularis oculi, nasalis, zygomaticus major, zygomaticus minor, levator labii superioris, orbicularis oris, depressor anguli oris, depressor labii inferioris, and mentalis, as well as for the masseter and temporalis as masticatory muscles for control.
Results: All muscles except the frontal (identification in 4/10 volunteers), procerus (4/10), risorius (6/10), and zygomaticus minor (8/10) were identified in all volunteers. Sex or age effects were not seen (all P > 0.05). There was no facial asymmetry with exception of the zygomaticus major (larger on the left side; P = 0.012). The exploratory examination of 5 patients revealed considerably smaller muscle volumes on the palsy side 2 months after facial injury. One patient with chronic palsy showed substantial muscle volume decrease, which also occurred in another patient with incomplete chronic palsy restricted to the involved facial area. Facial nerve reconstruction led to mixed results of decreased but also increased muscle volumes on the palsy side compared with the healthy side.
Conclusions: First systematic quantitative MRI volume measures of 5 different clinical presentations of facial paralysis are provided.
From the *Department of Otorhinolaryngology, Jena University Hospital, Jena, Germany; †Facial Nerve Center, Jena University Hospital, Jena, Germany; ‡Hans Berger Department for Neurology, Jena University Hospital, Jena, Germany; and §Medical Physics Group, Institute for Diagnostic and Interventional Radiology I, Jena University Hospital, Jena, Germany.
Received for publication November 28, 2013; accepted May 7, 2014.
Disclosure: Dr. Volk was supported by a grant from the Interdisciplinary Center for Clinical Research (IZKF), Jena University Hospital, Jena. Dr. Karamyan was supported by a grant from the German Academic Exchange Service (DAAD). No benefits in any form have been or will be received. Neither of the other authors has any financial disclosures. The Article Processing Charge was paid for by the authors.
Orlando Guntinas-Lichius, MD Department of Otorhinolaryngology, Jena University HospitalLessingstrasse 2, D-07740 Jena, Germany E-mail: email@example.com
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