Echogenic Area Of Substantia Nigra Research Articles

Echogenicity of basal ganglia structures in different Huntington's disease phenotypes.

In Huntington's disease (HD), a neurodegenerative-inherited disease, chorea as the typical kind of movement disorder is described. Beside chorea, however, all other kinds of movement disturbances, such as bradykinesia, dystonia, tremor or myoclonus can occur. Aim of the current study was to investigate alterations in the echogenicity of basal ganglia structures in different Huntington's disease phenotypes. 47 patients with manifest and genetically confirmed HD were recruited. All participants underwent a thorough neurological examination. According to a previously described method, classification into predominantly choreatic, mixed or bradykinetic-rigid motor phenotypes was performed depending on subscores of the Unified Huntington's Disease Rating Scale. In addition, findings in juvenile HD were compared to adult HD. Transcranial sonography was performed by investigators blinded to clinical classification. There were no significant differences in basal ganglia echogenicities between the three phenotypes. Size of echogenic area of substantia nigra (SN) correlated positively with CAG repeat and bradykinesia subscore, and negatively with age of onset and chorea subscore. Comparing juvenile and adult HD subtypes, SN hyperechogenicity was significantly more often detectable in the juvenile form (100 vs. 29.3 %, p = 0.002). Regarding echogenicity of caudate or lentiform nuclei, no significant differences were detected. HD patients with the juvenile variant exhibit marked hyperechogenicity of substantia nigra. No significant differences in basal ganglia echogenicities between predominantly choreatic, mixed or bradykinetic-rigid motor phenotypes were detected.

E27 Different Huntington's Disease Phenotypes And Echogenicity Of Basal Ganglia Structures

Background Beside Chorea all other kinds of movement disorders, such as bradykinesia, dystonia, tremor or myoclonus can occur in Huntington’s disease. Aim: Aim of the current study was to investigate alterations in the echogenicity of basal ganglia structures in different Huntington’s disease phenotypes. Method 47 patients with manifest and genetically confirmed HD were recruited. All participants underwent a thorough neurological examination. According to a previously described method, classification into predominantly choreatic, mixed or bradykinetic-rigid motor phenotypes was performed depending on subscores of the Unified Huntington’s Disease Rating Scale. In addition, findings in juvenile HD were compared to adult HD. Transcranial sonography was performed by investigators blinded to clinical classification. Results There were no significant differences in basal ganglia echogenicities between the three phenotypes. Size of echogenic area of Substantia nigra (SN) correlated positively with CAG-repeat and bradykinesia subscore, and negatively with age of onset and chorea subscore. Comparing juvenile and adult HD subtypes, SN-hyperechogenicity was significantly more often detectable in the juvenile form (100% vs. 29.3%, p = 0.002). Regarding echogenicity of caudate or lentiform nuclei, no significant differences were detected. Discussion HD patients with the juvenile variant exhibit marked hyperechogenicity of Substantia nigra. Thus, a distinct different underlying pathophysiology of the disease in juvenile compared to adult HD is discussed.

A new program for highly reproducible automatic evaluation of the substantia nigra from transcranial sonographic images

Recent studies report increased echogenicity of the substantia nigra (SN) in patients with Parkinson's disease (PD) using transcranial sonography (TCS). However, the main limitation to TCS is its dependence on the sonographer's experience. Experimental software for quantitative evaluation of the echogenic SN area was thus developed by us. The aim of this study was to test the reliability of the data using developed B-Mode Assist software in patients with parkinsonism and in healthy volunteers. The SN was imaged from the right temporal bone window in mesencephalic plane using TCS. DICOM images of SN were saved, converted into JPEG format, encoded and processed. Two observers performed 3 automatic evaluations of the SN area (measurements of SN area in each gray scale intensity inside the region of interest) by counting the standard deviation of all 6 measurements using developed software. The average value of all 3 measurements of each observer was used for computing Cohen's kappa coefficient to determine inter-observer correlations. Cohen's kappa coefficients as an intra-observer correlation for observer 1 and observer 2 were counted from the first 2 measurements of both observers. In total, 92 images were evaluated using this software. The mean of the standard deviations was 3.87; Cohen's kappa for intra-observer agreement of two observers were 0.947, and 0.943, resp.; Cohen's kappa for inter-observers agreement was 0.880. The agreement between visual and automatic detection of SN pathology was in 97.8% images. The sensitivity, specificity, positive and negative predictive values of automatic measurement were 100, 96.2, 95.1, 100%, resp. The results show very reliable measurement of SN features using designed application with "almost perfect" inter-observer and intra-observer agreements.

Sonographic abnormality of the substantia nigra in melanoma patients

Evidence derived from large epidemiological studies suggests an association between Parkinson's disease (PD) and malignant melanoma. Transcranial sonography of the midbrain reveals an extended echogenic substantia nigra (SN) area in a high proportion of patients with PD. This characteristic, in the context of PD, may signal degeneration of dopaminergic nigrostriatal projection neurons. Demonstration of an increased prevalence of abnormal echogenic SN in melanoma patients could add weight to the hypothesis of an underlying common pathogenic pathway of both diseases. This was a cross-sectional observational study. Transcranial sonography of the SN region was performed on 31 patients suffering from malignant melanoma and 29 healthy participants. In addition, patients and controls were screened for motor and non-motor symptoms of PD. The echogenic SN area was abnormally extended in 42% of melanoma patients versus 7% of control subjects (χ(2) = 9.811, P = .002). Mean echogenic SN area (SN[R, L]) was significantly larger in melanoma patients than in controls (patients, 0.21 ± 0.07 cm(2); controls, 0.15 ± 0.04 cm(2) [mean ± SD]; unpaired t test, P < .001). These findings provide additional evidence in favor of a common pathogenic pathway of PD and malignant melanoma and raise the possibility that their association is closer than previously assumed.

Structural abnormality of the substantia nigra in children with attention-deficit hyperactivity disorder

Structural abnormality of the substantia nigra can be detected by transcranial sonography in neuropsychiatric disorders such as Parkinson disease and restless legs syndrome. We investigated echogenicity of the substantia nigra as a potential structural marker for dysfunction of the nigrostriatal dopamine system in children with attention-deficit hyperactivity disorder (ADHD). We used a blinded design and determined echogenicity of the substantia nigra by use of transcranial sonography in 22 children with ADHD and 22 healthy controls matched for age and sex. The echogenic substantia nigra area was significantly larger in ADHD patients than in healthy controls (F(1,42) = 9.298, p = 0.004, effect size = 0.92). We found no effects of age or sex. Owing to a lack of dimensional assessment, we could not analyze the correlation between echogenicity and clinical symptoms. Our results support the hypothesis that the nigrostriatal dopaminergic system is abnormal in children with ADHD.

Substantia nigra echogenicity: A structural correlate of functional impairment of the dopaminergic striatal projection in Parkinson's disease

Transcranial sonography (TCS) reveals abnormal spatial extension of substantia nigra (SN) echogenicity in a high proportion of patients with Parkinson's disease (PD). It has been proposed that this abnormality represents a structural trait that is mechanistically distinct from degeneration of dopaminergic nigrostriatal projection neurons. We sought to clarify the relationship between sonographic abnormalities of SN and dysfunction of striatal dopaminergic neurotransmission. We studied 50 patients with PD. The spatial extension of the echogenic SN area was compared with the activity of presynaptic striatal dopamine reuptake transporters, assessed in the same patients by I-123-2-beta-carbomethoxy-3-beta-(4-iodophenyl)-tropane (beta-CIT) single-photon emission computed tomography (SPECT). Extension of echogenic SN area correlated (inversely) with striatal activity of presynaptic dopamine reuptake transporter in PD patients (R = -0.417; P = 0.003) and with the equivalent levodopa dose (R = 0.380; P = 0.006; linear regression analysis). Findings support the hypothesis that in PD abnormal extension of echogenic SN area provides a direct structural marker of degeneration of SN neurons. Therefore, in PD, TCS and beta-CIT assess pathophysiologically related phenomena.