Transcranial sonography in the discrimination of Parkinson's disease versus vascular parkinsonism.

Cerebro-vascular disease is a well-known cause of parkinsonism. However, so far, there are no standardized clinical criteria that allow the diagnosis with accuracy and reliability. Rather, there is a great symptom overlap between idiopathic Parkinson's disease, other causes for parkinsonism, and vascular parkinsonism. Therefore, additional instruments are necessary to improve diagnostic accuracy. Transcranial sonography of brain parenchyma (TCS) has become a broadly applied tool in the diagnosis of Parkinson's disease, and secondary and atypical parkinsonian syndromes. In contrast to patients with idiopathic Parkinson's disease, patients with vascular parkinsonism in general show no hyperechogenicity of the substantia nigra. In contrast to a number of patients with atypical parkinsonian syndromes, also the basal ganglia are usually normoechogenic on TCS. A more specific approach to vascular parkinsonism includes the Doppler or duplex technique in order to show stenosis of vessels. Therefore, the combination of TCS and Doppler/duplex imaging might help to improve diagnosis of vascular parkinsonism transcranial.