BACKGROUND:There is a growing research focus on the combination of blood oxygenation level dependent functional magnetic resonance imaging(BOLD-fMRI)and diffusion tensor imaging(DTI)to evaluate visual cortical function and structural changes in the cerebrum,as well as morphological changes to the white matter fiber tracks,after visual pathway lesions.However,the combined application of BOLD-fMRI and DTI in treating of visual pathway abnormalities still requires further studies. OBJECTIVE:To observe and evaluate the effects of hyperbaric oxygen on visual pathway abnormalities,and to evaluate the characteristics of cerebral function and anatomic structural changes by using BOLD-fMRI combined with DTI technique. DESIGN:Case contrast observation. SETTING:Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA.PARTICIPANTS:Sixteen patients(9 males and 7 females,15-77 years old)with lateral or bilateral visual disorder induced by visual pathway lesions were selected from the Department of Neurology,Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA from January 2006 to May 2007.These patients comprised the lesion group.Measures of interventional therapy:hyperbaric oxygen of two normal atmospheres for three courses(10 d/course)and routine internal medicine treatment.In addition,12 healthy subjects of similar sex and age to the lesion group were regarded as the control group.The control group underwent routine ophthalmological and ocular fundus examinations; diagnostic results were normal. The experiment received confirmed consent from the local ethic committee,and all patients provided informed consent.METHODS:BOLD-fMRI and DTI manifestations in the lesion group were observed before and after hyperbaric oxygen intervention,and the results were compared with the control group.The subjects were positioned on their back,and BOLD-fMRI images were collected with the following GRE EPI sequence:TR＝ 2 000 ms,TE＝40 ms,layer thickness＝5 mm,and 20-layer successive scanning to cover the whole brain. While,DTI images were collected with SE EPI sequence of single excitation:TR＝10 000 ms,TE＝112 ms, layer thickness＝4 mm,layer spacing＝0.5 rnm,and a 30-layer successive scanning,matrix＝128×128.A diffusion gradient was applied at 13 directions,and one layer without diffusion weighted imaging was collected at b＝1 000 s/mm2.Numbers of activated voxels in cortical-activated regions,and fractional anisotropy in bilateral cerebral optical radiation regions,were calculated.Displacement,continuity,and destruction of fibrous tracts were analyzed. MAIN OUTCOME MEASURES:Results of BOLD-fMRI and DTI examinations.RESULTS:All 16 patients and 12 controls were included in the final analysis.①Numbers of activated voxels through the use of BOLD-fMRI:prior to hyperbaric oxygen therapy,the number of activated voxels in the bilateral cortex of occipital lobe were significantly less in the lesion group than in the control group(t＝3.23,P＜0.01).In addition,the number of activated voxels significantly increased after treatment compared to before treatment(t＝2.46,P＜0.05).②Fractional anisotropy in optical radiation regions of bilateral cerebrum:fractional anisotropy in the lesion group was significantly less than the control group (t＝2.89,P＜0.05).In addition,fractional anisotropy after treatment was significantly higher than before treatment(t＝2.48,P＜0.05).Moreover,fractional anisotropy of optical neuropathy was significantly higher in 6 patients in the lesion group than the occipital lobe optical central lesion(t＝2.35,P＜0.05).CONCLUSION:BOLD-fMRI combined with DTI can indicate the occurrence,development,and therapeutic course of action for optical pathway lesions.The results acquired from these methods can rovide information for function and structure,which can provide reliable verification in the treatment of cerebral function.