Three-dimensional reconstruction and volume calculation of the intraorbital part of the optic nerve with high resolution MRI

Ilkan Tatar
2009 Anatomy (International Journal of Experimental and Clinical Anatomy)  
Optic nerve (ON) always takes attractions of the neuroscientists since the period of ancient scientists like Rufus of the Ephesus and Herophilus of the Chalcedon, accepted as the father of the modern Anatomy. Herophilus wrote his discoveries about the eye from his vivo-sections in the treatise called "On the eye". 1 He was first to differentiate between cranial and spinal nerves. He described at least seven pairs of cranial nerves and named six of the pairs as follows: optic, occulomotor,
more » ... occulomotor, trigeminal, facial, auditory, and hypoglossal. He meticulously differentiated and described at least four coats or membranes of the eye. He named them the cornea, retina, choroid, and iris. He delineated for the first time the ciliary body, which is the thickened portion of the tunica vasculosa between the choroid and the iris. He also described the vitreous humor. 2 When we looked at the Three-dimensional reconstruction and volume calculation of the intraorbital part of the optic nerve with high resolution MRI Abstract Objectives: Rapid improvements on MRI techniques in recent years brought the investigation of the optic nerve involvement in demyelinating diseases in a detailed manner. This revealed the need to establish standard criteria on defining the pathological conditions related to geriatric population such as optical atrophy, which is more frequently seen in developed countries as well as in our country. This than directed neuroanatomical and neuroradiological studies to the structures like optic nerve that is smaller and hence more difficult to identify with routine MRI sequences. Our aim was to obtain 3D reconstruction and volume calculation of the intraorbital part of the optic nerve from sequential MRI sections. Methods: In this study, 24 female and 24 male volunteers, aged between 20 and 40 have been investigated with T2 weighted MRI sequences with 2mm intervals. The imaging procedures have been performed with Siemens Allegra MRI equipment which has 3 Tesla of magnetic power. Approximately 10 serial sections, from the bulbus oculi to the optic canal, have been used to get the three-dimensional (3D) reconstruction. The 3D reconstruction was produced with the SurfDriver software. The volumes of the intraorbital parts of the optic nerve and their dural sheaths were calculated for either side. Results: The results have been compared with respect to some variables like age, gender, body mass index (BMI) and blood pressure. There was not any statistically significant difference between the volumes with respect to age, gender and BMI. Conclusion: The optic nerve sheath volumes, consequently the subarachnoidal space volumes were significantly increased in either side within the group that had higher values than the normal blood pressure, compared with the normal blood pressure group. anatomical point of view, the ON was always important and different from other cranial nerves as an elongation of the brain with the olfactory nerve. Again the great scientist from fertile crescent, also called mesopotamia, Ibn al Haytham, al-Basri or Alhazeni in western literature, gave his seven volume marvelous treatise about optics, light and vision theory called "Kitab el-Manazir". 3 Recently increasing interest on neurosciences, huge research budget for demyelinating diseases like multiple sclerosis (MS) and both qualitative and quantitative developments of imaging modalities especially on MRI are facilitate to observe ON and its pathologies in detailed manner. ON has a special potential for understanding pathophysiology and to make differential diagnosis of demyelinating diseases especially MS. 4 In addition to this ON diseases like optic neuritis provide very good model for studies on demyelinating diseases to understand pathogenetic mechanisms and to improve trustworthy imaging technique for ON atrophy measurement which facilitates that studies. 5-7 3D reconstruction and volume calculation of the intraorbital part of the optic nerve with HR-MRI Anatomy 2009; 3
doi:10.2399/ana.09.019 fatcat:tnuxkronxnblldalhkhlalmb7y