[Usefulness of transcranial sonography in Parkinson's disease. A comparative study using 123I-FP-CIT SPECT]

An increased echogenicity of the substantia nigra in patients with Parkinson's disease has been demonstrated by brain parenchyma sonography (BPS). BPS is a new and non-invasive technique that allows imaging of the brain in 2-dimensional axial slices. Changes in echogenicity can be displayed using ultrasounds. The aim of this study is to evaluate substantia nigra echogenicity in a group of Parkinson's disease patients and controls and compare with disease and functional neuroimaging parameters using ioflupane-single photon emission computed tomography (SPECT).

Fourty-two subjects were recruited consecutively. BPS and ioflupane-SPECT were performed in all.

Around 90% of Parkinson's disease patients showed a distinctive increase of echogenicity of substantia nigra above or equal 0.18 cm2, whereas this echo feature was detected in 11% of controls. Most of patients (86%) with an area of substantia nigra echogenicity above or equal 0.18 cm2 showed a nigro-striatal impairment, that is, a decreased ioflupane uptake measured by SPECT.

BPS is a useful tool in the diagnosis of Parkinson's disease. A good agreement between both techniques was achieved. The diagnosis accuracy obtained using BPS does not seem superior to ioflupane-SPECT. Nevertheless, hyperechogenicity could be considered as a vulnerability "marker" of the substantia nigra.