ABSTRACT
Approximately 10% of patients with a presumed diagnosis of Parkinson's disease (PD) remain misdiagnosed despite recent advances in neuroimaging. The current study addresses the use of transcranial sonography and single-photon emission computed tomography (SPECT) using (99m)Tc-TRODAT-1 to evaluate the echogenicity of the substantia nigra (SN) and the density of striatal presynaptic dopamine transporters, respectively, in a sample of 20 PD patients (13 males and 7 females) and 9 healthy subjects. The median age of the PD patients was 62 years. The median age at disease onset was 56 years, and the median disease duration was 5 years. The SN echogenic area was larger in PD patients than healthy subjects. The cut-off value of 0.22 cm(2) for the SN echogenic area was associated with 100% sensitivity and 78% specificity for the diagnosis of PD. Striatal and putaminal (99m)Tc-TRODAT-1 binding was lower in PD patients than healthy subjects. The cut-off value of 0.90 for the striatal (99m)Tc-TRODAT-1 binding was associated with 100% sensitivity and an 89% specificity for the diagnosis of PD, and the cut-off value of 0.76 for putaminal (99m)Tc-TRODAT-1 binding was associated with an 85% sensitivity and an 89% specificity. The size of the SN echogenic area did not correlate with the degree of striatal (99m)Tc-TRODAT-1 binding in PD patients. In conclusion, both SN hyperechogenicity and decreased striatal or putaminal (99m)Tc-TRODAT-1 binding constitute surrogate markers for differentiating PD patients from healthy individuals with a slightly higher diagnostic specificity of (99m)Tc-TRODAT-1 SPECT.
Subject(s)
Corpus Striatum/metabolism , Dopamine Plasma Membrane Transport Proteins/metabolism , Parkinson Disease/pathology , Adult , Aged , Corpus Striatum/diagnostic imaging , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Organotechnetium Compounds , Parkinson Disease/diagnostic imaging , Radiopharmaceuticals , Sensitivity and Specificity , Substantia Nigra/diagnostic imaging , Substantia Nigra/metabolism , Tomography, Emission-Computed, Single-Photon , Tropanes , Ultrasonography, Doppler, TranscranialABSTRACT
Transcranial sonography has become a useful tool in the differential diagnosis of parkinsonian syndromes. This is a non-invasive, low cost procedure. The main finding on transcranial sonography in patients with idiopathic Parkinson's disease is an increased echogenicity of the mesencephalic substantia nigra region. This hyperechogenicity is present in more than 90% of cases, and reflects a dysfunction in the dopaminergic nigrostriatal pathway. This study discussed how the hyperechogenicity of the substantia nigra may facilitate the differential diagnosis of parkinsonian syndromes.
A ultrassonografia transcraniana tem se tornado ferramenta útil no diagnóstico diferencial das síndromes parkinsonianas. Trata-se de um método não invasivo e de baixo custo. O principal achado da ultrassonografia transcraniana em pacientes com doença de Parkinson idiopática é o aumento da ecogenicidade, ou hiperecogenicidade, na região da substância negra mesencefálica, presente em mais de 90% dos casos, o que reflete disfunção da via dopaminérgica nigroestriatal. O presente trabalho abordou como a hiperecogenicidade da substância negra pode auxiliar no diagnóstico diferencial das síndromes parkinsonianas.
