Postnatal decrease in substantia nigra echogenicity. Implications for the pathogenesis of Parkinson's disease.

Increased echogenicity of the substantia nigra (SN) on transcranial ultrasonography (TCS) is a typical sign in Parkinson's disease (PD). Detected in healthy adults it is assumed to represent a risk factor for nigral injury. We studied at which time point of brain maturation increased signal intensity may occur by performing TCS scans in 109 newborns and children aged 0-192 months. While newborns regularly exhibit SN hyperechogenicity, this echofeature decreases substantially during the first years of life. As SN echogenicity is related to the tissue iron content in adults our findings suggest a failure in SN iron metabolism in some children with increased echogenicity during development which can be disclosed by TCS.