MRI measurement of the out-brain optic nerve based on neuro-optic plane(NOP) and compared with anatomical study

Objective:To evaluate the MRI features of optic nerve in normal adults and establish the normal standards of the optic nerve which from the origination to the optic chiasm,and compared with anatomical study.Methods:100 healthy adult volunteers were studied with GE 1.5T MRI echo speed plus system and phase array head coil.The sequences included T1WI,T2WI and fs-TSE-T2WI.Based on the neuro-optic plan(NOP),the first group was scanned on MRI and the second group(20 bodies) was dissected.Parts of the optic such as the thick part behind eyeball,intraorbital part and intra-canal part.All these diameters and lengths were measured on the MRI images and the bodies.Results:To the part nerve behind eyeball,intraobital part and intra-canal part,the diameters(mm) were 4.2±0.56,3.1±0.45,3.2±0.49,the length of intraorbital part and intra-canal part were 24.6±2.88 and 18.7±2.40,the total lengths was 43.3±3.83;the anatomical diameters were:3.9±0.30,3.8±0.40,3.4±0.39,the lengths were:23.9±3.00,17.4±1.37,41.2±3.00.Statistics found there were not obvious difference between sex and age of normal adults,the diameters of intraobital part and intra-canal part had difference between adults and bodies(P=0.000 and P=0.021,all 0.05),But the other 4 measurement results had no difference between the two groups(P0.05).Conclusion:NOP has the great useful to evaluate the optic nerve,MRI can show the normal optic nerve,which is a good imaging diagnostic method for the optic nerve and its lesions,but all the data which get from MRI are not well correlated with the anatomical studies.