| Part Ⅰ The alterations of regional homogeneity and amplitude of low-frequency fluctuation in dysthyroid optic neuropathy: A resting-state f MRI studyPurpose: To explore the changed regional homogeneity(Re Ho)and amplitude of low-frequency fluctuation(ALFF)of the brain using resting-state functional magnetic resonance imaging(rs-f MRI)in TAO patients with and without dysthyroid optic neuropathy(DON).Material and Methods: Totally,18 DON patients,26 TAO patients without neuropathy and 30 healthy controls(HC)were included,rs-f MRI were performed on all of the subjects.The brain Re Ho and ALFF of the three groups were calculated,ANOVA were performed among them for comparison,then,two-sample t test were performed to observe the difference between any two groups.Results: Re Ho:p<0.01,Alpha Sim corrected(1)Compared to HC,TAO patients showed increased Re Ho in anterior cingulate,right hippocampus and left parietal lobe;Re Ho values significantly decreased in right superior temporal gyrus,right occipital lobe,left anterior central gyrus,left middle frontal gyrus and right parietal lobe.(2)Compared to HC,DON patients showed increased Re Ho in left middle temporal gyrus,left fusiform gyrus,right hippocampus,superior posterior cingulate gyrus and right superior marginal gyrus;Re Ho values significantly decreased in Brodmann area 18/19 and right superior temporal gyrus.(3)DON patients showed increased Re Ho values in right middle temporal gyrus,posterior cingulate gyrus and central anterior gyrus in comparison with TAO,whereas,the Re Ho values of DON were decreased in Brodmann area 19 and the anterior cingulate.ALFF:p<0.01,Alpha Sim corrected(1)Compared to HC,TAO patients showed increased ALFF in anterior/ posterior cingulate,right hippocampus and cuneiform lobe;ALFF values significantly decreased in right middle/superior temporal gyrus and left anterior central gyrus.(2)Compared to HC,DON patients showed decreased ALFF in left fusiform gyrus and Brodmann area 18/19;ALFF values significantly increased in left inferior temporal gyrus,left inferior frontal gyrus,right frontal lobe and right hippocampus.(3)DON patients showed increased ALFF values in right middle temporal gyrus,right frontal medial gyrus and right central anterior gyrus in comparison with TAO,whereas,the ALFF values of DON were decreased in Brodmann area 19 and superior frontal gyrus.Conclusions:(1)DON patients was involved in abnormal Re Ho and ALFF in multiple brain region,which are mainly in visual cortices,when compared to TAO.(2)TAO patients showed abnormal alterations of bioelectric activity in brain region related to vision,which indicate the neuropathy in TAO happened much earlier than we have known.Part Ⅱ A diffusion tensor imaging study of visual pathway in patients with dysthyroid optic neuropathyPurpose: to observe the changes of visual pathway in patients with thyroid-associated ophthalmopathy(TAO)with and without dysthyroid optic neuropathy(DON)by using diffusion tensor imaging(DTI).Material and Methods: In this study,18 DON patients,26 TAO patients without neuropathy and 30 healthy controls(HC)were included,DTI examinations were performed on all of the subjects.The DTI parameters(FA,λ⊥,λ∥,MD)were calculated using an open-source software-DTI Studio.χ2 or two-sample t test were performed to compare the clinical parameters.One-way ANOVA analysis was performed among them for comparison of DTI parameters.Results:1)From healthy controls to TAO patients to DON patients,the λ∥ and FA values decreased gradually,whereas,the values of λ⊥ and MD increased orderly;2)All DTI parameters of optic nerve,in addition to FA of optic tract,λ⊥ of optic radiation showed significant statistical difference between the DON and TAO;3)In comparison with healthy controls,excepting for the FA and MD,λ⊥ of optic tract and FA of optic radiation,the remaining DTI parameters displayed significant discrepancies;4)The FA and λ⊥ of optic nerve,λ⊥ and λ∥ of optic chiasm in addition to MD and FA of optic tracts changed obviously when compared to HC.Conclusions: 1)The overall changes of the DTI parameters of each segment of the visual pathway of DON and TAO were as: decreased FA and λ⊥ together with increased λ⊥ and MD;2)The whole visual pathway of DON patients was involved in pathology damage,we may conjectured that the DON is that orbit-brain disease,which mainly manifest as visual function impairment;3)DTI can sensitively detect the subtle changes of the visual pathway in spite of no obvious visual function impairment,which may help to recognize the progress of DON. |
