Impact of readout-segmented echo-planar imaging based on small field of view and saturation band on image quality of orbital diffusion weighted imaging / 中国医学影像技术

ABSTRACT

Objective To observe the impact of readout-segmented echo-planar imaging(RS-EPI)based on small field of view(FOV)and saturation band on image quality of orbital diffusion weighted imaging(DWI).Methods Orbital MR scanning were prospectively performed in 33 healthy subjects.T1W,RS-RPI and optimized RS-EPI(based on small FOV and saturation band)images were acquired.Imaging quality of RS-EPI and optimized RS-EPI on displaying intraorbital structures(eyeballs,optic nerve and intraconal compartment)and periorbital structures(nasal cavity,orbital gyrus,optic chiasma,pituitary and temporal lobe)were evaluated subjectively using 5-point method.The geometric parameters of eyeball,signal-to-noise ratio(SNR)and apparent diffusion coefficient(ADC)were compared between images of RS-EPI and optimized RS-EPI.Results The display of eyeball,nasal cavity,orbital gyrus,optic chiasm,pituitary and temporal lobe on optimized RS-EPI were all better than those on RS-EPI(all P＜0.01),whereas no significant difference of optic nerve nor intraconal compartment was found between optimized RS-EPI and RS-EPI images(P＞0.05).Deformations of eyeball volume,sphericity,surface area,3D maximum diameter,axial maximum diameter and sagittal maximum diameter of bilateral eyes on optimized RS-EPI images were all slighter than those on RS-EPI(all P＜0.01),whereas no significant difference of deformations of coronal maximum diameters was found between optimized RS-EPI and RS-EPI images(P＞0.05).SNR of left temporal lobe white matter and ADC of vitreous body on optimized RS-EPI images were both lower than those on RS-EPI(both P＜0.01),whereas no significant difference of ADC of left temporal lobe white matter nor that of pons was found between optimized RS-EPI and RS-EPI images(P＞0.05).Conclusion Optimized RS-EPI with small FOV and saturation band could be used to improve imaging quality of orbital DWI.