FA And T2*Values Of Quantitative Research In The Substantia Nigra Pars Compacta Of Early Parkinson’s Disease

Objective:Quantitative study of FA and T2*values were made in thesubstantia nigra pars compacta in early Parkinson’s disease （PD）,to explorethe changs of characteristic of FA and T2*values in the substantia nigrapars compacta of early Parkinson’s disease.Methods:It was checkd for20patients of early PD diagnosed byphysician and28normal controls with sex and age matched by using magneticresonance imaging sequences of DTI、ESWAN and T2WI. Use magneticresonance imaging (MRI) sequences of DTI and ESWAN to copy T2WIsequence. Post-processing of the images of DTI and ESWAN separately wascarried on. Selecting T2WI images as reference images,Chose the clearestslice of the substantia nigra pars compacta on T2WI image to enlarge theimage; delineated outline of the left and right side of the substantia nigra parscompacta manually.FA and T2*values in region of interest were respectivelymeasured and recorded for statistical analysis.Scanning methods:1Sagittal and coronal T1WI images were obtained by scanning thesagittal and coronal plane of the brain;2T2WI sequence of axial plane was perpendicular to brain stem on thecoronal plane. From genu to splenium of corpus callosum on the Sagittalplane,3mm thickness, no interval,20layers of continuous scanning, includingthe most of the midbrain, pons and medulla oblongata;3Positioning of DTI and ESWAN sequences of axial plane: Thesequence of DTI copied the thickness, the layer interval and number layer ofT2WI sequence. The sequence of ESWAN copied the range and direction ofT2WI sequence.Post-processing of the images of DTI and ESWAN separatelywas carried on by GE workstation ADW4.3version FUNCTOOL software. First DTI image was correted to decrease image distortion caused by mildhead movement or eddy current. Then selected T2WI images as referenceimages and fused the two images. On the fused images, adjusted windowwidth and level to T2WI sequence and chose the clearest level of thesubstantia nigra pars compacta on T2WI image to enlarge the image;delineated outline of the left and right side of the substantia nigra parscompacta manually; The substantia nigra pars compacta was delineated anddivided into six large circular region of interest manually. The1-2、3-4、5-6circular region of interest were merged into three areas and average valueswere calculated, representing head、body and tail FA values of the substantianigra pars compacta; Then cleared the6circular region of interest and retainedthe outline delineated of bilateral substantia nigra pars compacta. From theoutside to inside and from cephalic to the caudal,the average9small circularregion of interest were respectively placed, Each value of ROI was recorded.the outside of1-9and the inside of1-9FA values of circular region of interestwere respectively calculated and recorded. Measurement method of T2*value was the same as FA value.All values were respectively measured by two radiologists and the resultswere averaged., The FA and T2*values of refinement of the substantia nigrapars compacta was measured and recorded. The FA values and T2*values ofthe lateral,head、body and tail of substantia nigra pars compacta werestatistically analyzed by using independent samples t-test (n <40) between PDand the control. Scatter plots and correlation analysis were made for the FAvalues and T2*values of lateral, head, body and tail of substantia nigra parscompacta; FA values and the T2*ROC curve analysis was made between PDand normal control group, It was measured for sensitivity and specificity of FAvalues and T2*values in the different regional to the diagnosis of PD in thedifferent regional.All statistical analyzes were performed using SPSS13.0software.Results:1FA values decreased obviously (P <0.05)in the substantia nigra pars compacta of early PD, the FA values of head, body and tail refined in nigracompact were lower than normal control group, and FA values of the head ofthe lateral area decreased more obviously.2T2*values decreased (P <0.05)in the substantia nigra pars compactaof early PD significantly, T2*values of only parts of region in head,body andtail refined in nigra compact decreased than the control group.3FA values of head lateral area decreased significantly (P<0.05) in thesubstantia nigra pars compacta of early PD, the degree of decline to24.4%.Conclusion:1FA value and T2*values are lower and FA value decreased moremeaningful than T2*values in the substantia nigra pars compacta of earlyParkinson’s disease.2There is no linear correlation between the T2*value and FA value inthe substantia nigra pars compacta of early PD. Sensitivity and specificity ofFA value is more better than T2*value for early diagnosis of PD.3The decrease of FA values of head lateral area in the substantia nigrapars compacta is important to the diagnosis of early PD.