A Study Of The Cutoff Values And The Diagnostic Value Of Transcranial Sonography In The Diagnosis Of Parkinson’s Disease

Objective:To establish the cutoff values of transcranial sonography (TCS) in patients with Parkinson’s disease (PD) by receiver operating characteristic curve (ROC curve) and study the diagnostic value of TCS in PD.Methods:228PD patients and167controls were included for this study. All the individuals were tested by TCS. The respective areas of hyperechogenicity of substantial nigra (SN) and ipsilateral midbrain were measured, and the area of SN/the area of ipsilateral midbrain ratio (S/Ml ratio) was calculated. The sum areas of the bilateral Substantia nigra hyperechogenicity/the whole area of the midbrain ratio (S/M2ratio) was also calculated. Using ROC curve, the cutoff values of SN, S/M1and S/M2and their respective sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. The correlations of SN, S/Ml and S/M2with the clinical features of PD patients would be judged. All the subjects with insufficient temporal windows on one side or both sides were excluded in this study.Results:A total of228PD patients and167controls were examined, and70PD patients and51controls were excluded due to insufficient temporal bone windows.158PD patients and116controls were included actually in the study.(1) In the PD group, SN, S/Ml and S/M2were significantly higher than that of the control group (P<0.001).(2) The cutoff values of SN, S/M1and S/M2established by ROC curve in our laboratory were0.18cm2,0.07,0.04, respectively. The sensitivity, specificity, PPV and NPV of SN, S/M1and S/M2were63.3%,70.7%,78.7%,70.7%;60.8%,79.3%,80.0%,79.3%and80.0%,68.1%,76.4%,59.7%, separately. The areas under ROC curve for SN、S/M1and S/M2were0.757,0.749,0.771, respectively. The three types of ultrasonic indicators have showed a medium diagnostic accuracy.(3) SN is associated with the duration of PD (p<0.001); S/M1is associated with the duration and UPDRSⅢ of PD (p<0.05); S/M2is associated with UPDRSⅢ of PD (p<0.05).Conclusion:Our study indicates that SN, S/Ml and S/M2can be applied as a ultrasonic diagnostic indicator separately in the diagnosis of PD. The cutoff values of SN, S/M1and S/M2established by ROC curve in our laboratory are0.18cm2,0.07,0.04. The three kinds of ultrasonic indicators have showed a medium diagnostic accuracy. This study suggests that the availability of temporal windows is directly related to the sensitivity and specificity of the cutoff values, which stands for the diagnostic value ofTCS in PD.