Role of Transcranial Ultrasound in the Diagnosis of Movement Disorders

Transcranial B-mode sonography (TCS) may provide supplementary information to other neuroimaging methods, adding valuable information to the diagnosis and differential diagnosis of movement disorders. The value of TCS in the differential and early diagnosis of Parkinson disease (PD) has been proven. There is increasing evidence that substantia nigra hyperechogenicity, the ultrasound marker typical for PD, may disclose a nigrostriatal vulnerability if found in healthy people, which may contribute to defining high-risk groups for this neurodegenerative disorder. This article provides information about the ultrasound procedure, its specific diagnostic value, and its limitations. Pathophysiologic mechanisms leading to changes in the reflection of ultrasound waves are discussed.