How to measure substantia nigra hyperechogenicity in Parkinson disease: detailed guide with video

Systematic review-based guideline "Parkinson's disease" of the German Society of Neurology: diagnostic use of transcranial sonography

BACKGROUND AND OBJECTIVE

Transcranial brain parenchyma sonography (TCS) has been recommended as a tool for the early and differential diagnosis of Parkinson's disease (PD) in German and European clinical guidelines. Still, the brain structures to be examined for the diagnostic questions and the requirements for being a qualified investigator were not specified in detail. These issues have now been addressed in the 2023 update of the clinical guideline on PD by the German Society of Neurology (DGN).

METHODS

The recommendations were based on a systematic literature review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

Three diagnostic questions were defined: (1) What is the accuracy of TCS in the differential diagnosis of PD versus atypical and secondary Parkinsonian syndromes? (2) What is the accuracy of TCS in the differential diagnosis of PD versus essential tremor? (3) What is the accuracy of TCS in the diagnosis of PD in persons with typical early symptoms, compared with the diagnosis established by clinical follow-up? The brain structures to be assessed and the level of recommendation were formulated for these questions. The training requirements for being regarded as qualified TCS investigator were stipulated by the responsible medical societies (German Society of Ultrasound in Medicine, DEGUM; German Society for Clinical Neurophysiology and Functional Imaging, DGKN). Finally, the recommendations for these diagnostic questions reached strong consensus (each ≥ 97%) of the guideline committee. Here, the details of review and recommendations are presented.

CONCLUSION

The updated guideline clarifies the diagnostic uses and limitations of TCS in PD.

Comparison of Transcranial Sonography and [18 F]-Fluorodopa PET Imaging in GBA1 Mutation Carriers

BACKGROUND

Mutations in GBA1 are a common genetic risk factor for parkinsonism; however, penetrance is incomplete, and biomarkers of future progression to parkinsonism are needed. Both nigral sonography and striatal [¹⁸ F]-FDOPA PET assay dopamine system health, but their utility and coherence in this context are unclear.

OBJECTIVE

The aim of this study is to evaluate the utility and coherence of these modalities in GBA1-associated parkinsonism.

METHODS

A total of 34 patients with GBA1 mutations (7 with parkinsonism) underwent both transcranial studies for substantia nigra echogenicity and [¹⁸ F]-FDOPA PET to determine striatal tracer-specific uptake (K_i ).

RESULTS

Larger nigral echogenic areas and reduced striatal K_i were exclusively observed in parkinsonian patients. Sonographic and PET measurements showed strong inverse correlations but only in individuals with clinical parkinsonism.

CONCLUSIONS

Close correspondence between nigral echogenicity and striatal presynaptic dopamine synthesis capacity observed only in GBA1 carriers with parkinsonism provides validation that these two modalities may conjointly capture aspects of the biology underlying clinical parkinsonism but raises questions about their utility as predictive tools in at-risk subjects. © 2022 International Parkinson and Movement Disorder Society.

Diagnostic Ability of Structural Transcranial Sonography in Patients with Alzheimer's Disease

The aim of this study was to assess the diagnostic ability of transcranial sonography (TCS) for the evaluation of the medial temporal lobe (MTL) in Alzheimer's disease (AD). Standard neuropsychological evaluation, TCS and 1.5 T MRI were performed for 20 patients with AD and for 20 age- and sex-matched healthy controls in a prospective manner. Measurements of the size of the third ventricle and heights of the MTL (A) and the choroidal fissure (B) were performed twice on each side by two independent neurosonologists for all participants. On MRI, both conventional and volumetric analyses of the third ventricle and hippocampus were performed. Receiver operating characteristic (ROC) curves analyses were applied. Height of the MTL on TCS had sensitivities of 73.7% (right)/63.2%(left) and specificities of 65% (right)/65-70% (left) Area under a curve (AUC) 75.4-77.2% (right), 60.4-67.8% (left)) for AD. A/B ratio on TCS had sensitivities of 73.7% (right)/57.9% (left) and specificities of 70.0% (right)/55.0% (left) (AUC 73.3% (right), 60.4% (left)) by the experienced neurosonologist, and sensitivities of 78.9% (right and left) and specificities of 60.0% (right)/65.0% (left) (AUC 77.8-80.0%) by the inexperienced neurosonologist for AD. On MRI, linear measurement of the hippocampus and parahippocampal gyrus height had sensitivities of 84.2% (right)/89.5% (left) and specificities of 80.0% (right)/85% (left) (AUC 86.1-92.9%) for AD. Hippocampal volume had sensitivities of 70% (right and left) and specificities of 75% (right)/80% (left) (AUC 77.5-78%) for AD. Atrophy of the right MTL in AD could be detected on TCS with a good diagnostic ability, however MRI performed better on the left.

A transcranial sonography study of brainstem and its association with depression in idiopathic generalized epilepsy with tonic-clonic seizures

Brainstem raphe (BR) hypoechogenicity in transcranial sonography (TCS) has been depicted in patients with depression. But, up to date, the association of BR alterations in TCS with depression in patients with epilepsy has never been reported. This study was to investigate the possible role of BR examination via TCS in patients with idiopathic generalized epilepsy with tonic-clonic seizures (IGE-TCS) and depression. Forty-six patients with IGE-TCS and 45 healthy controls were recruited. Echogenicity of the caudate nuclei (CN), lentiform nuclei (LN), substantia nigra (SN), and BR and widths of the lateral ventricle (LV) frontal horns and the third ventricle (TV) were assessed via TCS. The determination of depression was based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV), and depression severity measured by Chinese version Neurological Disorders Depression Inventory for Epilepsy (C-NDDI-E) and Beck Depression Inventory-II (BDI-II). The width of TV in patients with epilepsy was found significantly larger than that in healthy controls (p = 0.001), but there was no significant difference in TV width between patients with IGE-TCS with and without depression. There were no significant differences between patients with IGE-TCS and healthy controls in LV frontal horn width, as well as in SN, CN, LN, and BR echogenicity. Here, it seems that patients with IGE-TCS were detected with smaller SN echogenic area compared with controls though they had no statistical significance. Patients with IGE-TCS with hypoechogenic BR had significantly higher C-NDDI-E and BDI-II scores than those with normal BR signal, and most patients with IGE-TCS with depression exhibited hypoechogenic BR, but few patients with IGE-TCS without depression exhibited hypoechogenic BR. In conclusion, BR echogenic signal alterations in TCS can be a biomarker for depression in epilepsy, but it might not be associated with epilepsy itself. The alterations of SN echogenic area and TV width in TCS may reflect a potential role of SN and diencephalon structure in the pathogenesis of epilepsy, which needs to be further elucidated.

Hypoechogenicity of brainstem raphe correlates with depression in migraine patients

Background

Brainstem raphe (BR) hypoechogenicity in transcranial sonography (TCS) has been depicted in patients with major depression (MD) and in depressed patients with different neurodegenerative diseases. But, up to date, the association of BR alterations in TCS with depression in migraineurs has never been reported. This study was to investigate the possible role of BR examination via TCS in migraineurs with depression.

Methods

Forty two migraine without aura (MwoA) patients and 40 healthy controls were recruited. Echogenicity of lentiform nuclei (LN), caudate nuclei (CN), substantia nigra (SN) and brainstem raphe (BR) and width of the frontal horns of the lateral ventricles and the third ventricle were assessed with TCS. The diagnosis of depression was based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders IV (DSM –IV), and the severity of depression was measured by Hamilton Rating Scale for Depression (HAM-D) and Hospital Anxiety and Depression Scale depression subscale (HADS-D).

Results

There were no significant differences between migraineurs and controls in the width of frontal horn of the lateral ventricle (p = 0.955), width of third ventricle (p = 0.129) as well as in the echogenicity of SN (p = 0.942), CN (p = 0.053), LN (p = 0.052) and BR (p = 0.677). Here, it seems that more migraineurs were detected with increased echogenecity of CN and LN compared with controls (33.3% versus 15.0% for CN, 19.0% versus 5.0% for LN) though they had no statistical significance. Patients with hypoechogenic BR had significantly higher HAM-D and HADS-D scores than those with normal BR signal (p = 0.000 for both HAM-D and HADS-D), and most (83.33%) migraineurs with depression exhibited hypoechogenic raphe but none (0.00%) of the migraineurs without depression exhibited hypoechogenic raphe (p = 0.000).

Conlusions

TCS signal alteration of BR can be a biomarker for depression in migraine but it is not associated with migraine headache itself. LN and CN alterations in TCS may reflect a potential role of them in the pathogenesis of migraine, which needs to be further elucidated.

Does normal substantia nigra echogenicity make a difference in Parkinson's disease diagnosis? A real clinical practice follow-up study

OBJECTIVES

Substantia nigra hyperechogenicity (SN+) detected by transcranial ultrasound (TUS) is useful for Parkinson's disease (PD) diagnosis. Approximately 15% false negative results of unknown significance are reported. However, most TUS studies are transversal, and diagnosis of PD may change during follow-up.

METHODS

Analysis of our prospective registry of TUS in clinical practice, selecting patients with sufficient bone window, to whom TUS was performed because of suspected PD, and a minimum of 3-year follow-up. Subjects were classified regarding SN echogenicity (SN+/SN-).

RESULTS

172 patients (122 SN+, 50 SN-), mean age 71 years (25-90), were included. At the end of follow-up, PD diagnosis was retained by 91% SN+ vs. 54% SN- subjects (p < 0.0001), while final diagnosis of atypical parkinsonism (3%SN+ vs. 16%SN-, p:0.0059) was more frequent in SN-. Dopaminergic therapy response was associated with SN+ (88% SN+ vs. 50% SN-, p < 0.0001), as were abnormal DaTSCANs (90%SN+ vs. 56%SN-, p 0.0027). SN echogenicity had 80% sensitivity and 68% specificity for PD diagnosis, while SPECT had 91% and 73%, respectively. SN+ was the only baseline predictor of keeping PD diagnosis at the end of follow-up, with an odds ratio of 12 (95% CI 3-42) (p < 0.001).

CONCLUSIONS

In our sample of patients with suspected PD, SN hyperechogenicity predicted PD diagnosis in the long term with a high odds ratio. Conversely, a baseline normal SN echogenicity was associated with a poorer response to PD therapy and change to a different diagnosis from PD. Normal SN appears to be a caveat for clinicians to check for atypical parkinsonism features during follow-up.

Transcranial Sonographic Alterations of Substantia Nigra and Third Ventricle in Parkinson's Disease with or without Dementia

Background:

Numerous studies have demonstrated that patients with Parkinson's disease (PD) have a higher prevalence of substantia nigra (SN) hyperechogenicity compared with controls. Our aim was to explore the neuroimaging characteristics of transcranial sonography (TCS) of patients with PD and those with PD with dementia (PDD). The correlation between the echogenicity of the SN and clinical symptoms in Chinese patients with PDD was also assessed.

Methods:

The ratios of SN hyperechogenicity (SN+), maximum sizes of SN+, and widths of third ventricle (TV) were measured using TCS for all the recruited patients. Data were analyzed using one-way analysis of variance, rank-sum test, Chi-square test, and receiver-operating characteristic (ROC) curve analysis.

Results:

The final statistical analysis included 46 PDD patients, 52 PD patients, and 40 controls. There were no significant differences in ratios of SN+ and maximum sizes of SN+ between PDD and PD groups (P > 0.05). TV widths were significantly larger in PDD group (7.1 ± 1.9 mm) than in PD group (6.0 ± 2.0 mm) and controls (5.9 ± 1.5 mm, P < 0.05); however, the ratios of enlarged TV did not differ among the three groups (P = 0.059). When cutoff value was set at 6.8 mm, the TV width had a relatively high sensitivity and specificity in discriminating between PDD and PD groups (P = 0.030) and between PDD group and controls (P = 0.003), based on ROC curve analysis. In PDD patients, SN+ was more frequently detected in akinetic-rigid subgroup, and patients with SN+ showed significantly higher Hoehn and Yahr stage and Nonmotor Symptoms Questionnaire scores (P < 0.05).

Conclusions:

Compared to Chinese patients with PD, patients with PDD had a wider TV, altered SN sonographic features, and more severe clinical symptoms. Our findings suggest that TCS can be used to assess brain atrophy in PD and may be useful in discriminating between PD with and without dementia.

Hyperechogenicity of the Substantia Nigra in Parkinson's Disease: Insights from Two Brothers with Markedly Different Disease Durations

We present clinical features and substantia nigra morphology for two brothers with Parkinson's disease (PD) aged 60 and 59 years. The brothers were diagnosed at 41 and 50 years of age, respectively. Both patients exhibited an abnormally large area of substantia nigra echogenicity bilaterally when viewed with transcranial ultrasound. The abnormality was similar in both brothers despite one having a much longer disease duration than the other. These findings further highlight that transcranial ultrasound is not associated with severity of clinical symptoms, but it might assist in the diagnosis of PD provided that it is combined with other variables known to precede PD.

Standards in neurosonology. Part III

The paper presents standards related to ultrasound imaging of the cerebral vasculature and structures. The aim of this paper is to standardize both the performance and description of ultrasound imaging of the extracranial and intracranial cerebral arteries as well as a study of a specific brain structure, i.e. substantia nigra hyperechogenicity. The following aspects are included in the description of standards for each ultrasonographic method: equipment requirements, patient preparation, study technique and documentation as well as the required elements of ultrasound description. Practical criteria for the diagnosis of certain pathologies in accordance with the latest literature were also presented. Furthermore, additional comments were included in some of the sections. Part I discusses standards for the performance, documentation and description of different ultrasound methods (Duplex, Doppler). Part II and III are devoted to standards for specific clinical situations (vasospasm, monitoring after the acute stage of stroke, detection of a right-to-left shunts, confirmation of the arrest of the cerebral circulation, an assessment of the functional efficiency of circle of Willis, an assessment of the cerebrovascular vasomotor reserve as well as the measurement of substantia nigra hyperechogenicity).

Substantia Nigra Echogenicity Predicts Response to Drug Withdrawal in Suspected Drug-Induced Parkinsonism

Introduction

Response to drug withdrawal in patients with suspected drug-induced parkinsonism (DIP) is of prognostic and therapeutic importance, but cannot be predicted solely on clinical information. The aim of this study was to validate SN hyperechogenicity (SN+) assessed by transcranial sonography as a predictor of response to drug withdrawal in this group of patients.

Methods

Patients were diagnosed according to previously published criteria and prospectively included in the study. All patients were followed until complete recovery of parkinsonian symptoms or at least for 6 months after discontinuation of the offending drug and then diagnosed as DIP or parkinsonism following neuroleptic exposure (PFNE). Transcranial sonography (TCS) findings were compared with the clinical diagnosis.

Results

Sixty patients comprised the group for the final analysis. Sixteen patients were classified as PFNE and 44 as DIP. The area of SN echogenicity was significantly increased in the PFNE group (0.23 cm²; standard deviation [SD]: 0.04), compared to the DIP group (0.14 cm²; SD, 0.05; one-way analysis of variance; P < 0.001). Normal SN was significantly associated with complete recovery after withdrawal of the parkinsonism-inducing drug (P < 0.0005). Accuracy of SN+ to distinguish PFNE from DIP was: sensitivity 81.2%; specificity 84.1%; positive predictive value 47.4%; and negative predictive value 96.2%.

Conclusions

We believe that SN+ assessed with TCS is a valid prognostic marker in the setting of suspected DIP. It is a nonexpensive, feasible technique that can be implemented for proper counseling and guidance of treatment decisions.

Sonography for diagnosis of Parkinson disease-from theory to practice: a study on 300 participants

OBJECTIVES

Hyperechogenicity of the substantia nigra on transcranial sonography is used for diagnosing Parkinson disease (PD). Cutoff values for the substantia nigra echogenic area, defining substantia nigra hyperechogenicity, vary among ultrasound systems from different manufacturers. In this study we wanted to determine the cutoff criterion for a Toshiba (Tokyo, Japan) system and to assess its diagnostic value.

METHODS

Three hundred participants (controls, n = 138; patients with PD, n = 105; and patients with essential tremor, n = 57) underwent transcranial sonography following a standardized protocol.

RESULTS

The substantia nigra was assessable in 92.7% of all participants. The substantia nigra echogenic area (larger of bilateral measurements) was larger in patients with PD (mean ± SD, 0.24 ± 0.05 cm(2)) than controls (0.14 ± 0.05 cm(2); P < .001) and patients with essential tremor (0.14 ± 0.04 cm(2); P < .001). Substantia nigra echogenicity was larger in male participants (0.20 ± 0.07 cm(2)) than female participants (0.15 ± 0.06 cm(2); P< .001). Age did not correlate with substantia nigra echogenicity in any group. Frontal horn width was larger and lenticular nucleus hyperechogenicity and a discontinuous raphe were more frequent in the PD group than the other groups. On multivariate analysis, only substantia nigra hyperechogenicity was associated with the diagnosis of PD. The 90th-percentile substantia nigra echogenic area in the control group, which defined marked substantia nigra hyperechogenicity, also represented the optimum cutoff value for discrimination of PD from non-PD participants on receiver operating characteristic curve analysis (area under the curve, 0.913; Youden index, 0.73). This cutoff value (≥0.21 cm(2), larger of bilateral measurements) yielded sensitivity of 83% and specificity of 90% for the diagnosis of PD.

CONCLUSIONS

Transcranial sonography shows good diagnostic validity for diagnosis of PD when implemented according to a strictly standardized protocol.

Transcranial brain parenchymal sonography in neurodegenerative and psychiatric diseases

Transcranial sonography is a highly sensitive noninvasive sonographic method for detection of early and specific echogenic changes in basal ganglia of patients with some neurodegenerative diseases. Transcranial sonography showed substantia nigra hyperechogenicity as a typical echo feature in idiopathic Parkinson disease and lenticular nucleus hyperechogenicity as a characteristic finding in atypical parkinsonian syndromes. Brain stem raphe hypoechogenicity or interruption has been shown to be highly prevalent in patients with unipolar depression as well as depression associated with certain neurodegenerative diseases. Transcranial sonography also revealed basal ganglia hyperechoic changes in movement disorders with trace metal accumulation such as Wilson disease, some entities of neurodegeneration with brain iron accumulation, as well as several forms of spinocerebellar ataxia. Transcranial sonography is a valuable neuro imaging method for early and differential diagnosis and follow-up of patients with neurodegenerative and psychiatric diseases.