2 Parkinson and parkinsonism: The role of transcranial B-mode sonography

Background The use of transcranial B-mode sonography (TCS) to assess brainstem has become an important tool for the diagnosis of movement disorders. Although substantia nigra (SN) hyperechogenicity can be found in more than 90% of Idiopatic Parkinson’s disease (IPD) patients, it is very rarely found in patients with atypical parkinsonism. Methods The objective was to evaluate the effectiveness of TCS in diagnosis of IPD and parkinsonism. TCS was performed in a group of 51 patients (mean age: 69.3 years). Twenty-five patients (49%) had a clinical diagnosis of IPD; 21 patients (41%) had parkinsonism (12 multiple system atrophy (MSA), 2 progressive supranuclear palsy (PSP), 2 vascular parkinsonism and 3 iatrogenic parkinsonism). Five patients (10%) had essential tremor (ET). Cardiac 123 metaiodobenzylguanidine (MIBG) scintigraphy was performed in 21 patients. Results In 20 patients with IPD (80%), in 1 patient with MSA (8%), in 1 patient with PSP (33%), in 3 patients with iatrogenic parkinsonism (100%) and in 5 patients with ET (100%) TCS showed an increased SN hyperechogenicity. Cardiac MIBG SPECT was positive in 8 patients with IPD; in 7 patients there was an overlap between the cardiac MIBG SPECT and TCS. Sensitivity of TCS was of 77% in IPD and 93% in MSA and PSP; specificity was 72% in IPD and 97% in MSA and PSP. Conclusions Although the limitation due to the bone window, TCS represents a non invasive approach and it has wide availability. This makes it an useful tool on improving the clinical diagnosis for several movement disorders.