Assessment of the visual pathways in patients with neurofibromatosis-1 by 3S-space technique with 3-Tesla MRI

Ozge Sarac ,Ali Varan,Oktay Algin ,Mehmet Beyazal,Banu Anlar ,Adile Tülay Kansu

doi:10.3906/sag-1906-14

Abstract

Background/aim We aimed to evaluate the size/tortuosity of the optic nerve (ON) and the dilatation of the ON sheath (ONS) in neurofibromatosis type 1 (NF-1) patients with 3T-MRI, and to assess the usefulness of 3D-SPACE in imaging the optic pathway, ON, and ONS in NF-1 patients. Materials and methodsTwenty consecutive NF-1 patients without optic pathway glioma (OPG) (Group 1), 16 consecutive NF-1 patients with OPG (Group 2), and 19 controls were included in this study. The thickness and tortuosity of the ON and the diameter of the ONS were measured on STIR and 3D-SPACE images. ResultsThe thickness of the ON was similar in all groups on STIR images (P>0.05). The mean ONS diameter was higher in Group 2 with this sequence (P=0.009). Controls had significantly lower grades of ON tortuosity than Groups 1 and 2 (P=0.001), and Group 1 had significantly lower ON tortuosity compared to Group 2 (P=0.001). Severe tortuosity was only detected in Group 2. ConclusionON tortuosity and ONS diameter were increased in NF-1 patients in the presence of OPG. High-resolution cranium imaging with the 3D-SPACE technique using 3T-MRI seems to be helpful for detection of the optic pathway morphology and pathologies in NF-1 patients.

Highlights

Neurofibromatosis type 1 (NF-1) is an autosomal dominant neurocutaneous disorder characterized by multiple neurofibromas, cutaneous pigmentation, and skeletal dysplasia [1]
The thickness of the optic nerve (ON) was similar in all groups on short tau inversion recovery (STIR) images (P>0.05)
ON tortuosity and ON sheath (ONS) diameter were increased in NF-1 patients in the presence of optic pathway gliomas (OPGs)

Summary

Introduction

Neurofibromatosis type 1 (NF-1) is an autosomal dominant neurocutaneous disorder characterized by multiple neurofibromas, cutaneous pigmentation, and skeletal dysplasia [1]. Numerous central nervous system (CNS) manifestations have been identified in NF-1 including optic pathway gliomas (OPGs), optic nerve tortuosity, cerebral astrocytomas, hydrocephalus, and neurofibromatosis bright objects (NBOs) on imaging [3]. OPGs are the most common CNS neoplasms in NF-1, encountered in 15% of NF-1 patients [1,4]. They generally involve the anterior visual pathway. 45% are Magnetic resonance imaging (MRI) is the method of choice for detection and evaluation of OPGs and other intracranial manifestations of NF-1 because of its higher soft-tissue contrast resolution and radiation-free multiplanar imaging capability [9]. Many patients with NF-1 undergo MRI during childhood

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