Application of quantitative measurement on midbrain in Parkinson disease with MR susceptibility-weighted imaging

Objective To evaluate the measurement of phase value,width and the ratio of the width to the midbrain diameter of nuclei of midbrain in diagnosing Parkinson disease(PD) with susceptibility-weighted imaging(SWI).Methods The phase values,widths and diameters were measured in 20 patients with PD,including earlier-onset PD group(n=13) and middle-later-onset PD group(n=7).Control group included 14 normal adults.The results of measurement were analyzed and compared,at the same time patients with PD were graded according to Hoehn Yahr grading,and then correlation analysis was carried out among the phase value,width,the ratio and Hoehn Yahr grading.Results Compared with control group,the phase values of sustantia nigra pars compacta(SNc) in earlier-onset PD group and middle-later-onset PD group significantly decreased(P0.01).The phase values of SNc and sustantia nigra pars reticulata(SNr) in middle-later-onset PD group significantly decreased compared with those in earlier-onset PD group(P0.01,P0.05).Compared with control group,the widths of SNc in earlier-onset PD group and middle-later-onset PD group decreased(P0.05,P0.01).The widths of SNc and SNr in middle-later-onset PD group significantly decreased compared with those in earlier-onset PD group(P0.01).Compared with control group and earlier-onset PD group,the SNc width/midbrain diameter in middle-later-onset PD group decreased(P0.01).In PD patients,the phase values of SNc and SNr were negatively correlated with Hoehn Yahr grading(r=-0.602,P0.01;r=-0.445,P0.05),the widths of SNc and SNr negatively correlated with Hoehn Yahr grading(r=-0.828,P0.01;r=-0.667,P0.01),the phase value of SNc positively correlated with the width and width/midbrain diameter(r=0.590,P0.01;r=0.445,P0.05),the phase value of SNr positively correlated with the width(r=0.493,P0.05).Conclusion Measurement of phase value,width and the ratio of the width to the midbrain diameter of nuclei of midbrain with SWI is reliable to diagnose PD.