Magnetic resonance imaging features in moebius syndrome: a pilot study

Purpose To investigate with unconventional neuroimaging (UNI) the alterations of the brain structures in patients affected by Moebius Syndrome (MBS). Methods 7 MBS patients underwent MRI evaluation of the brain and the brainstem with 3.0T MRI through volumetric sequences (FLAIR 3D, BRAVO, CUBE T2); high resolution T2 imaging (FIESTA) and Diffusion Tensor Imaging (75 directions, ST: 3 mm) were also performed to better evaluate all cranial nerves. Data analysis and full‐brain tractography were obtained using Functool software. We measured the dimensions of the brainstem in MBS patients and compared the obtained values with the AIRO's (Italian Association of Radiation Oncology) standard data. Results Brainstem resulted abnormal when compared to controls; in particular we found an hypoplasia of both the midbrain (6 cases) and the medulla (3 cases). In all the cases the VI and VII cranial nerves resulted hypo‐ or aplasic; fiber tracking and color coding in the DTI analysis showed a lack of uniformity in the brainstem and in the cerebellar peduncles. We also found a prevalence of abnormal transverse pontine fibers colonizing the cortical spinal tracts bilaterally (6 cases). We documented: thinner corpus callosum (4 cases), reduction of the internal auditory meatus and cisterna magna (1 case). Conclusions Our data show new relevant alterations of the brainstem in MBS patients investigated with UNI; we suppose that this could be related to a misdirection of the axonal guidance paths during the embryogenesis secondary to the abnormal development of the VIthand VIIth cranial nerves nuclei. We also found anomalies in the supratentorial region which need further investigations. A correlation of the features herein observed with the ophthalmological pattern of MBS may provide further insight in the pathogenesis of this disease.