Is transcranial sonography useful for diagnosing Parkinson's disease in clinical practice?

Transcranial sonography (TCS) is an emerging ancillary examination for diagnosing Parkinson's disease (PD). Objective: To evaluate TCS features in patients with PD and its mimics, and establish their accuracy in predicting the final clinical diagnosis after follow-up. Methods: We retrospectively studied 85 patients with an initial clinical suspicion of PD, atypical parkinsonism or essential tremor, all of whom underwent TCS. Two specialists reviewed the follow-up clinical visit records and determined the final clinical diagnosis. The accuracy analysis of the TCS was determined using Bayesian statistical methods. Results: The finding of substantia nigra hyperechogenicity (> 20 mm(2)) showed high sensitivity (93.4%) and specificity (86.6%). The positive likelihood ratio showed 6.93-fold greater odds for diagnosing PD than an alternative condition when this finding was present. Conclusions: This study revealed the practical usefulness of TCS in differentiating PD from its prevalent mimics when the clinical diagnosis was initially unclear.