Transcranial sonography of substantia nigra in patients with Parkinson’s disease

Transcranial sonography of substantia nigra in patients with Parkinson's disease

Hideto Miwa

Department of Neurology, Wakayama Medical University

Substantia nigra (SN) hyperechogenicity can be visualized by transcranial sonography (TCS) as a stable finding in approximately 90% of patients with Parkinson's disease (PD) or dementia of Lewy body (DLB). It is also observable in about 10% of healthy controls. The exact cause of SN hyperechogenicity in patients with PD/DLB remains undetermined. However, it has been proposed that SN hyperechogenicity is a biomarker of vulnerability of dopaminergic neurons in SN that is associated with increased iron levels. SN hyperechogenicity is stable and does not change with advancing illness. In addition, it is speculated that SN hyperechogenicity may be present before development of parkinsonian motor symptoms. It is thus expected that TCS of SN may be used for preclinical evaluation of subjects at risk of developing PD or DLB.

Address correspondence to Dr.Hideto Miwa, Department of Neurology, Wakayama Medical University(811-1 Kimiidera, Wakayama-city, Wakayama 641-8510, Japan)