Magnetic resonance and dopamine transporter imaging for the diagnosis of Parkinson´s disease: a narrative review

BACKGROUND

the diagnosis of Parkinson's disease (PD) can be challenging, especially in the early stages, albeit its updated and validated clinical criteria. Recent developments on neuroimaging in PD, altogether with its consolidated role of excluding secondary and other neurodegenerative causes of parkinsonism, provide more confidence in the diagnosis across the different stages of the disease. This review highlights current knowledge and major recent advances in magnetic resonance and dopamine transporter imaging in aiding PD diagnosis.

OBJECTIVE

This study aims to review current knowledge about the role of magnetic resonance imaging and neuroimaging of the dopamine transporter in diagnosing Parkinson's disease.

METHODS

We performed a non-systematic literature review through the PubMed database, using the keywords "Parkinson", "magnetic resonance imaging", "diffusion tensor", "diffusion-weighted", "neuromelanin", "nigrosome-1", "single-photon emission computed tomography", "dopamine transporter imaging". The search was restricted to articles written in English, published between January 2010 and February 2022.

RESULTS

The diagnosis of Parkinson's disease remains a clinical diagnosis. However, new neuroimaging biomarkers hold promise for increased diagnostic accuracy, especially in earlier stages of the disease.

CONCLUSION

Future validation of new imaging biomarkers bring the expectation of an increased neuroimaging role in the diagnosis of PD in the following years.

Cell-based technologies for Huntington's disease

Huntington's disease (HD) is a fatal genetic disorder, which causes the progressive breakdown of neurons in the human brain. HD deteriorates human physical and mental abilities over time and has no cure. Stem cell-based technologies are promising novel treatments, and in HD, they aim to replace lost neurons and/or to prevent neural cell death. Herein we discuss the use of human fetal tissue (hFT), neural stem cells (NSCs) of hFT origin or embryonic stem cells (ESCs) and induced pluripotent stem cells (IPSCs), in clinical and pre-clinical studies. The in vivo use of mesenchymal stem cells (MSCs), which are derived from non-neural tissues, will also be discussed. All these studies prove the potential of stem cells for transplantation therapy in HD, demonstrating cell grafting and the ability to differentiate into mature neurons, resulting in behavioral improvements. We claim that there are still many problems to overcome before these technologies become available for HD patient treatment, such as:

a) safety regarding the use of NSCs and pluripotent stem cells, which are potentially teratogenic;

b) safety regarding the transplantation procedure itself, which represents a risk and needs to be better studied; and finally

c) technical and ethical issues regarding cells of fetal and embryonic origin.

Language impairment in Huntington's disease

Language alterations in Huntington's disease (HD) are reported, but their nature and correlation with other cognitive impairments are still under investigation. This study aimed to characterize the language disturbances in HD and to correlate them to motor and cognitive aspects of the disease. We studied 23 HD patients and 23 controls, matched for age and schooling, using the Boston Diagnostic Aphasia Examination, Boston Naming Test, the Token Test, Animal fluency, Action fluency, FAS-COWA, the Symbol Digit Modalities Test, the Stroop Test and the Hooper Visual Organization Test (HVOT). HD patients performed poorer in verbal fluency (p<0.0001), oral comprehension (p<0.0001), repetition (p<0.0001), oral agility (p<0.0001), reading comprehension (p=0.034) and narrative writing (p<0.0001). There was a moderate correlation between the Expressive Component and Language Competency Indexes and the HVOT (r=0.519, p=0.011 and r=0.450, p=0.031, respectively). Language alterations in HD seem to reflect a derangement in both frontostriatal and frontotemporal regions.

Correlation between disc displacements and locations of disc perforation in the temporomandibular joint

OBJECTIVES

The aim of this study was to investigate the correlation between disc displacement types and locations of disc perforation in the temporomandibular joint (TMJ).

METHODS

157 patients (162 joints) with disc perforation observed through arthroscopy were included in this study. The types of disc displacement were analysed by TMJ MRI before operation. The locations of disc perforation under arthroscopy were recorded. The correlation between types of disc displacement and locations of disc perforation was analysed by Fisher's exact test.

RESULTS

Medial disc perforation was observed in 55.6% of patients with anterolateral displacement without reduction, but was observed in only 3.7% of patients with pure anterior displacement, and was not observed in patients with anteromedial displacement without reduction. There was a statistically significant difference between these groups in the incidence of medial disc perforation.

CONCLUSIONS

There is a correlation between different disc displacements and locations of disc perforation. The incidence of medial disc perforation in patients with anterolateral displacement was significantly higher. The types of disc displacement may have direct influence over the locations of disc perforation.

[Assessment of erectile dysfunction in patients with Parkinson's disease]

Thirty men having Parkinsons disease (PD) and 30 controls were studied prospectively by the use of the International Index of Erectile Function (IIEF) to assess erectile dysfunction (ED). Of the patients with PD (mean age of 59 years), 46.66% referred to the practice of sexual activity. All of the parkinsonians were using antiparkinsonian medication. In the control group (mean age of 63 years), 76.66% referred to the practice of sexual activity, 46.60% to arterial hypertension and 6.66% to diabetes mellitus. The median score for the PD group according to the IIEF was 34, and that for the controls 50. The main differences between the two groups were in the erectile function, orgasmic function and satisfaction with the sexual relationship. The IIEF is a multidimensional scale widely accepted to assess the ED. The data obtained suggest that ED is more frequent among parkinsonians and points out to the role of DP in the genesis of ED.

Avaliação da disfunção erétil em pacientes com doença de Parkinson

Trinta indivíduos portadores de doença de Parkinson (DP) e 30 indivíduos controle foram estudados prospectivamente, através do Índice Internacional de Função Erétil (IIFE) a propósito de avaliar a ocorrência de disfunção erétil (DE). Dos pacientes com DP (idade mediana de 59 anos), 46,66% referiram prática de atividade sexual. Todos parkinsonianos usavam medicação antiparkinsoniana. Neste grupo, 30,00% tinham hipertensão arterial e 6,66% diabetes melitus. No grupo controle (idade mediana de 63 anos), 76,66% declararam prática de atividade sexual; 46,6% tinham hipertensão arterial e 6,66% diabetes mellitus. Escore médio para portadores de DP no IIFE foi 34 e para os controles 50. As principais diferenças entre os dois grupos foram quanto à função erétil, função orgasmo e satisfação com a relação sexual. O IIFE é uma escala amplamente aceita para avaliação da disfunção erétil. Os dados obtidos sugerem que a DE é mais frequente entre parkinsonianos, ressaltando o papel da DP como causa de DE nesse grupo.

Huntington disease: DNA analysis in Brazilian population

Huntington disease (HD) is associated with expansions of a CAG trinucleotide repeat in the HD gene. Accurate measurement of a specific CAG repeat sequence in the HD gene in 92 Brazilian controls without HD, 44 Brazilian subjects with clinical findings suggestive of HD and 40 individuals from 6 putative HD families, showed a range from 7 to 33 repeats in normal subjects and 39 to 88 repeats in affected subjects. A trend between early age at onset of first symptoms and increasing number of repeats was seen. Major increase of repeat size through paternal inheritance than through maternal inheritance was observed. Data generated from this study may have significant implications for the etiology, knowledge of the incidence, diagnosis, prognosis, genetic counseling and treatment of HD Brazilian patients.

Huntington's disease

Huntington's disease is a genetically inherited degenerative neuropsychiatric disorder, characterized by motor alterations, including involuntary movements such as chorea, dementia and psychiatric disturbances. In this article, the authors review the clinical features of the disease. They also analyze some genetic and pathophysiologic aspects, that can help to improve our understanding of this disorder involving the basal ganglia.

[Blepharospasm: treatment with botulinum toxin]

Blepharospasm is form of focal dystonia characterized by involuntary and repetitive contractions involving the orbicular oculi muscle. Fourteen patients with blepharospasm were submitted to botulinum toxin type A injections. Of these 14 cases, 6 were male and 8 female. The mean age was 58 years (range: 33 to 76 years) with illness duration ranging from 1 to 25 years (average: 7.3 years). All patients have been treated with conventional therapies with poor results, but presented a good response to botulinum toxin type A. The average latent period was 3 days (range: 0 to 10); maximum effect of treatment was observed after 16 days. The mean duration of maximum response was 90 days. The main side effects of botulinum toxin injections were ptosis and lagophtalmos.

Delayed complications of pancreatic injury: role of CT in detection and management

Pancreatic injury is rare. There is however a recent increase of incidence due to high velocity motor vehicle accidents and urban violence. Diagnosis can be missed during initial assessment. Complications are common due to associated organ injuries. We report on the role of CT in the diagnosis and management of four cases with pancreatic injury of different mechanisms and delayed complications. Advantages and pitfalls of CT are discussed.

[Kinesigenic paroxysmal choreoathetosis. Report of a case treated with carbamazepine]

Paroxysmal choreoathetosis (PC) is a rare entity, and professionals who study movement disorders do not find it easily. Paroxysmal occurrence of dystonic, choreic, athetosic movements is the typical feature of this syndrome. The onset is always subtle and the attacks can last from few seconds to hours. Sporadic cases and more common familial cases have been reported. The therapeutic approach with anticonvulsant drugs like carbamazepine is not always successful. However, there is a good response to this drug in the kinesigenic form of PC. The case of a 21 years old male patient is reported here. The onset occurred during puberty, at 14 years old. Neurologic examination was normal between attacks. Subtle and brief choreic, athetosic and dystonic limb and legs movements precipitated by sudden quick and unexpected passive movements, as by startle, were observed during the attacks. There was no familial history. Routine laboratorial investigation, EEG, CT scan and MRI did not show significant changes. Carbamazepine in low dosages (100 mg/day) brought a complete control of the attacks.

Wilson's disease: magnetic resonance imaging (MRI) with clinical correlations in 16 cases

The purpose of this study was to evaluate MRI findings in a group of patients with Wilson's disease, trying to establish possible correlations between clinical and image data. Sixteen patients (8 males and 8 females), with ages ranging from 11 to 50 years, and duration of illness ranging from 5 months to 32 years, were submitted to MRI in a 1.5T System. Four patients were asymptomatic, 4 had mild neurological findings, 2 were moderately affected and the remaining 6 had a severe form of the disease. All patients were receiving D-penicillamine by the time of the study. The most symptomatic patients presented five or more sites of abnormalities on MRI. The putamen was affected in all symptomatic individuals and one asymptomatic and 11 of them presented dystonia on neurological examination. A striking feature was the peripheral localization of putaminal hyperintense lesions on T2 weighted images. In eight cases, striatum or "substantia nigra" lesions explained parkinsonism observed on neurological examination. MRI seems to be an efficient method to study neurological involvement of Wilson's disease allowing some interesting anatomo-clinical correlations.

[Parkinsonism secondary to ethylene oxide exposure: case report]

Ethylene oxide is a gas widely used in the production of industrial chemicals. It is also used to sterilize heat-sensitive medical supplies. Previous reports of acute and chronic exposure have described neurotoxic effects like peripheral neuropathy and cognitive impairment. We describe a pure parkinsonian syndrome following acute ethylene oxide intoxication. A 39-years-old male was referred to our Movement Disorders Clinic for evaluation of a parkinsonian syndrome. He was acutely exposed to ethylene oxide four years before and remained comatose for three days, and gradually regained consciousness. At that time he showed a global parkinsonian syndrome including bradykinesia, rigidity and rest tremor, with a severe motor disability; no other neurological disorders were found. The symptomatology was partially controlled with biperidene and levodopa plus carbidopa. Two years later he developed L-dopa induced dyskinesias. Four years after the intoxication he was evaluated at our clinic. General examination showed no abnormalities. Neurologic examination revealed a normal mental status. Motor evaluation disclosed moderate bradykinesia, rigidity and rest tremor, shuffling gait, poor facial mimic, stooped posture, and his speech was low and monotonous; deep tendon reflexes were brisk. The Hoehn-Yahr disability score was degree IV. Routine laboratory and radiological exams showed results within normal limits. The CSF examination was normal. Brain computed tomography and magnetic ressonance were normal. A trial with bromocriptine and levodopa plus carbidopa did not improve dyskinesia, and he was put on a schedule including amantadine and biperidene with improvement to grade III in Hoehn-Yahr scale. In the present case there was a clear relation between the acute exogenous intoxication and irreversible parkinsonism.(ABSTRACT TRUNCATED AT 250 WORDS)

Traumatic callosotomy

In a 33 years-old epileptic woman with a traumatic impact to the vertex, clinical and radiological studies (skull X-R, CT and MRI) disclosed an extensive callosal section under the topography of the falx, associated to fronto-basal contusions. There was a significant improvement in the epileptic syndrome. No interhemispheric disconnection syndrome could be determined, which is compatible with the posterior regions of the corpus callosum having been spared. This is, to the best of our knowledge, the most extensive callosal injury documented by MRI to date.

[Zinc in the treatment of hepatolenticular degeneration: report of 3 cases]

Three patients with symptoms and signs of hepatolenticular degeneration (HLD) who developed serious renal side effects of D-penicillamine (DP) had their therapeutic schedule changed to zinc. Patient 1, a 55 year-old man had been well until 12 years old, when skeletal changes (osteomalacia) due to tubular renal disturbance began. His diagnosis of HLD had first been established at age of 32 when he presented with "wing-beat" tremor. He was then begun on DP and his neurological symptoms resolved within one year of initiating therapy but skeletal abnormalities remained unchanged as a sequel. During the next 22 years the patient was continued on DP therapy but with poor compliance. Then the reappearance of his neurological manifestations occurred several times. By the age of 53, after one year without therapy, his neurological status has worse. DP was reinstituted but some weeks later his renal laboratory parameters became severely affected. DP was discontinued and zinc sulfate (220 mg three times daily) was introduced. On this therapeutic regimen his renal laboratory parameters returned to previous level after one month. Within one year on this therapeutic regimen neurological manifestations were resolved. After 31 months on zinc treatment he remains neurologically asymptomatic and his renal function is satisfactory. Patient 2, a 41 year old woman had been her diagnosis of HLD at age of 20, when following the diagnosis of the disease in her old brother, she was found to have the laboratory features of HLD and bilateral Kayser-Fleischer rings. DP treatment was recommended at that time but she quit the follow-up. When she was 23, an esophageal variceal bleeding occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Eating epilepsy

Eating epilepsy is a rare type of reflex epilepsy. A 24 years-old male with eating reflex complex partial seizures was submitted to clinical, neurological, neuroradiological and EEG studies. Neurologic and CT examinations were normal. EEG recordings including video-EEG monitoring during meals disclosed focal abnormalities related to both temporal lobes prevailing at the left side and secondary bilateral synchrony mainly in more anterior regions. Ictal findings were similar to the interictal secondary bilateral synchrony except for its longer duration. PB, VPA and DPH monotherapies were ineffective. High dose CBZ monotherapy yielded good but incomplete seizure control. Since a big number of precipitants could be involved, no specific physiopathological basis could be established.

Knowledge about epilepsy among teachers and epileptic patients

223 epileptics patients and their families and 136 teachers from public and private schools were submitted to similar questionnaires related to inheritance, transmission, cure, complication rates, care during seizures, need for information on the disease, habits, comparison with other diseases and to the educational and social performance of epileptics. Cure and complication rates accounted for the main differences between those populations. Epileptics could recognize a bigger number of complications but still expected to be cured from the disease. The majority of teachers and patients have never been informed about epilepsy and this finding was related to the big number of equivocal answers obtained from them. Put together, the data showed that social and educational performance of epileptic patients could be disturbed by medical and social parameters. Some of them could be improved by an educational program towards these aspects of epilepsy.