Diffusion Tensor Imaging Study In White Matter Of Ultra-high-risk For Psychosis

Objective: Diffusion tensor imaging (diffusion tensor imaging, DTI)technology were used to investigate the abnormal changes in white matter ofultra-high-risk for psychosis(UHR).Methods：Studys selection：UHR group of individuals is determined bythe psychiatrist who familiar with the instrument of Structural interview ofschizophrenia syndrome(SIPS)， through interview and supplementaryinformations by formed families in the way of written and oral forevaluation.Exclude previous and (or) existing psychosis, identify high-riskgroups,include15cases.Control group recruited by advertisement，collected17cases of normal control.The age of the two groups are16-30years old, allsubjects are Han nationality, the right-handed,no obvious organic brain lesions,wechsler intelligence scale for assessing>70IQ points. DTI data acquisition：Siemens3.0T superconductive MR scanner (Trio, Siemens Medical Erlangen,Germany) is used to collect the data of brain structure and DTI.15UHR and17normal controls underwent scan.With fractional anisotropy (fractional anisotropy,FA) scores as the measure,the imaging data were mainly processed by tract-based spatial statistics (TBSS) toolbox in Functional Software Library(http://www.fmrib.ox.ac.uk/fsl).Tract-based spatial statistics(TBSS) wasperformed to measure the fractional anisotropy (FA) of the wholebrain.pretreatment is done by head movement and eddy currentcorrection,generating the whole brain mask and getting individual FAmaps.Then Get the average FA image skeleton and enrichment by nonlinearregistration,comparing FA value of the whole brain after individual FA map isprojected again. Statistical Analysis： Using TFCE (Threshold-Free Cluster Enhancement) method for multiple correction.UHR group and the control group forindependent samples t-test.Differences between groups were compared byindependent samples t-test, and p<0.05as the significant standard,Resultsdisplay intuitively in the form of pseudo-color.Results:1）Compare with the control group, UHR group has lower meanFA values；2）There are differences of white matter in the left frontal lobe andthe left anterior limb of internal capsule（Corrected P<0.01）.Conclusions:1) The microstructural of whole-brain white matter was alteredin ultra-high-risk for psychosis.2）The structure and integrity of white matter in the left frontallobe and the left anterior limb of internal capsule damage in ultra-high-risk forpsychosis;3）Before the first onset of schizophrenia,white matter changesin the microstructure may already exist.