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This paper gives an overview of the clinical importance of SPECT and PET imaging of the dopaminergic system in the differential diagnosis and for the determination of the progression rate of Parkinson's disease (PD). D2 receptor imaging can help to differentiate multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) from PD. In patients treated with neuroleptics it is possible to determine the rate of striatal D2 receptor blockade using this technique. This occupancy rate parallels the occurrence of parkinsonian side effects. Its measurement helps in the selection of newer atypical neuroleptics, which can be used to treat drug-induced psychosis in PD because they do not aggravate parkinsonian symptoms. Imaging of dopaminergic neurons with [123I]beta-CIT SPECT or [18F]DOPA PET is a way to visualize and quantify the nigrostriatal dopaminergic lesion in PD. Findings correlate with clinical rating scales and demonstrate the feasibility of detecting the preclinical lesion in patients with hemiparkinson or familial PD. [123I]beta-CIT SPECT can easily distinguish patients with essential tremor and patients with "lower body parkinsonism" due to a subcortical vascular encephalopathy. MSA and PSP cannot be separated from PD with this method alone. Longitudinal studies with [123I]beta-CIT SPECT and [18F]DOPA PET can quantify the progression rate in PD. SPECT results from our own group show a low rate of progression in patients with a long duration of disease and a more marked progression rate in patients with shorter disease duration. In the former group regions in the striatum with higher beta-CIT binding at the time of the first SPECT scan decline faster than regions with lower binding. These findings suggest a curvilinear course of progression which starts at different time points in different striatal regions and which levels off after several years of disease duration. These findings are in line with data from PET studies and underline the importance of an early start of neuroprotective strategies. Preliminary data from PET and SPECT studies in early PD suggest that dopamine agonists might have a slight neuroprotective effect and might slow down the rate of progression of the disease.
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PMID:SPECT and PET imaging of the dopaminergic system in Parkinson's disease. 1119 11

We report a 57-year-old woman with progressive gait disturbance and mental deterioration. She was well until March 1995, when she was 54 years of the age. At that time she noted a gradual onset of tremor and difficulty using her hand. Similar symptoms appeared in her right hands, and she visited another hospital, where 300 mg of levodopa and 7.5 mg of bromocriptine were prescribed. These medication did not help her symptoms. In the summer of 1996, she became to fall down easily. In September of the same year, she started to repeat the same words many times. She was unable to stop it. She was hospitalized to our service on January 25, 1997. On admission, she was alert but demented moderately; her Hasegawa dementia scale was 15/30. She showed palilallia, logoclonia, and echolalia. She showed constructional apraxia and questionable left-right disorientation. She had marked vertical gaze palsy with preserved oculocephalic response. She had masked face and small voice. Her gait was wide based with small steps. No muscle atrophy or weakness was noted. She showed only mild rigidity in the neck, but no rigidity was noted in the limb. No tremor was noted. She was bradykinetic. Deep tendon reflexes were symmetric and within normal limits. Laboratory findings on admission was unremarkable. MRI showed atrophy of the brain stem as well as cerebral cortical areas, particularly in the fronto-temporal region. Her hospital course was complicated with paralytic ileus and septicemia. She developed hypotension and pronounced dead on July 28, 1998. She was discussed in the neurological CPC. The chief discussant arrived at a conclusion that the patient had progressive supranuclear palsy and died of septic shock. All the participants wondered between PSP and CBD, but majority agreed with this diagnosis of the chief discussant. Only one thought that she might have had corticobasal degeneration rather than PSP, because of dementia, cortical atrophy in MRI, and lack of limb rigidity. Postmortem examination revealed cortical and brain stem atrophy. In the premotor cortex, marked astrocytosis and ballooned neurons were seen. Furthermore, astrocytic plaques were seen; this is considered to be pathognomonic for CBD. The substantia nigra showed marked neuronal loss and gliosis, but no neurofibrillary tangles or Lewy bodies were seen. Gliosis was also seen in the globus pallidus and in the medial thalamus. The pathologic diagnosis was corticobasal degeneration. This patient was very interesting case, in that the clinical manifestations appeared to be consistent with PSP, yet pathologic diagnosis was CBD. Lack of limb rigidity may be atypical for advanced PSP. In addition, palilalia appears to be more associated with CBD.
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PMID:[A 57-year-old woman with progressive disturbance of gait and mental deterioration]. 1121 88

GAIT ARRESTS: They affect the evolution of the disease. This freezing phenomenon which induces falls sometimes constitutes an initial sign. Like the gait initiation failure, freezing can be controlled by sensory stimulation, notably visual inputs, but also by more sustained attention. FALLS ARE MAINLY CONNECTED WITH BOTH POSTURAL INSTABILITY AND RIGIDITY: They are poorly influenced by dopaminergic therapies. The progressive decrease of step width represents a main factor in their occurrence. PRECOCITY OF GAIT DISORDERS IS UNUSUAL IN PARKINSON'S DISEASE: Other parkinsonian syndromes such as progressive supranuclear palsy, multiple system atrophy and vascular parkinsonian syndrome must then be evoked. Their association with a cognitive impairment and abnormal sphincter behaviour infers a diagnosis of normal pressure hydrocephalus. GAIT IMPROVES WITH L-DOPA THERAPY: Speed, step length and duration of the swing phase are increased without change of cadence. Progressive loss of L-dopa efficiency on gait and postural stability contrasts with the persistent effect on tremor, rigidity and bradykinesia; a functional abnormality of nondopaminergic systems can explain these symptoms. In the following stages, gait troubles increased by motor fluctuations and abnormal involuntary movements are less controlled by L-dopa therapy. PHYSICAL THERAPY PLAYS A MAJOR ROLE IN THERAPEUTIC MANAGEMENT: An individual or collective rehabilitation project must be established according to the stage of evolution; the exercises aim to protect postural control and coordination. Visual or sound rhythmic inputs can be employed in the case of gait initiation failure. THE EFFECTS OF FUNCTIONAL NEUROSURGERY ARE IN THE COURSE OF EVALUATION: Thermolesion and chronic electrical stimulation of deep brain structures have opposite effects on gait troubles. Bilateral thalamotomy or pallidotomy are sometimes a source of disequilibrium. Chronic thalamic stimulation does not induce either benefits or adverse effects. On the other hand, stimulation of the internal pallidum improves gait kinematic parameters; improved postural adjustments have also been reported. The effect of subthalamic nucleus stimulation is comparable to that of L-dopa, however the long-term effect remains to be evaluated.
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PMID:[Gait disorders in Parkinson disease. Gait freezing and falls: therapeutic management]. 1128 86

We reported a 64-year-old woman in the early stage of progressive supranuclear palsy presenting as pure akinesia syndrome who showed marked improvement with tandospirone citrate. She revealed bradykinesia, severe frozen gait and disturbance of postural reflex without rigidity or tremor. Treatment with L-dopa and L-threo DOPS was not effective, but tandospirone citrate at a daily dosage of 30 mg significantly lessened the severity of frozen gait. Activation single photon emission computed tomography study with 99mTc-ethyl cysteinate dimer during gait revealed a significant increase in brain activity in the right cingulate cortex after tandospirone citrate treatment. The effect lasted ten months until neck rigidity and ventricular supranuclear palsy were evident.
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PMID:[Effects of tandospirone citrate on frozen gait in patients with early stage of progressive supranuclear palsy, investigated by walk-induced activation single photon emission computed tomography method]. 1133 96

Positron emission tomography (PET) and single photon emission computed tomography (SPECT) provide the means to studying in vivo the neurochemical, hemodynamic or metabolic consequences of the degeneration of the nigrostriatal dopaminergic system in Parkinson's disease (PD). The extent of striatal dopaminergic denervation can be quantified with radiotracers as [18F]FDopa for PET and [123I]tropanes for SPECT. There are other radiotracers such as [11C]Dopa and meta-tyrosines as well as PET tracers for uptake sites. Striatal uptake of [18F]FDopa and [123I]tropanes is markedly decreased in PD, more in the putamen than in the caudate nucleus, and inversely correlates with the severity of motor signs and with duration of disease. PET and SPECT make possible the assessment by noninvasive means of the changes in dopamine receptor density, the effect of neuronal transplants or neuroprotective treatments in PD patients, or the nigrostriatal dopaminergic function in at-risk subjects. Activation studies using cerebral blood flow and metabolism measurements during a motor task reveal an impaired ability to activate the supplementary motor area and dorsolateral prefrontal cortex in PD. This functional disability is reversed by the use of dopaminergic medication or by surgical treatment by pallidotomy or deep brain stimulation. The differential diagnosis between PD and multiple system atrophy, progressive supranuclear palsy or corticobasal degeneration is not yet clearly established by PET and SPECT, even though these syndromes have some particular neurochemical and metabolic profiles. On the other hand, PET and SPECT are useful for distinguishing PD from Dopa-responsive dystonia, or for assessing the integrity of the nigrostriatal dopaminergic pathway in atypical cases of postural tremor or iatrogenic parkinsonian syndromes.
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PMID:Contributions of PET and SPECT to the understanding of the pathophysiology of Parkinson's disease. 1181 73

Atypical parkinsonian syndromes (APS) such as multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration are characterized by poor response to antiparkinsonian medication and rapid clinical deterioration. We used SPECT and [123I]beta-CIT as a label of dopamine transporters to study the progression of presynaptic dopaminergic degeneration in Parkinson's disease (PD) and APS. Twenty-four PD patients with short disease duration (2.4 +/- 1.5 years), 12 PD patients with long disease duration (9.2 +/- 2.6 years), 10 patients with APS (disease duration 2.1 +/- 1.5 years), and nine patients with essential tremor (ET) underwent sequential [123I]beta-CIT SPECT imaging with an interval of 25.5 +/- 10.3 (13-63) months. The age-related decline of striatal beta-CIT binding was studied cross-sectionally in 30 healthy subjects. The ratio of striatum/cerebellum -1 at 20 hours after tracer injection, reflecting specific-to-nondisplaceable binding, was used as the primary SPECT outcome measure. At scan 1, striatal beta-CIT binding was reduced in PD patients with short disease duration (-42% compared with age-corrected normal values) and long disease duration (-51%), and APS (-36%), but normal in ET. During the observation period striatal beta-CIT binding significantly declined in patients with APS (14.9% per year) and short duration PD (7.1% per year), whereas PD patients with long disease duration and patients with ET showed no significant change of striatal beta-CIT binding between scans 1 and 2. The relative annual reduction from age-corrected normal values at the time of scan 1 was significantly higher in patients with APS than in PD patients with short disease duration (9.6 vs. 4.3%, P = 0.004). These results demonstrate a rapid decline of striatal beta-CIT binding in patients with atypical parkinsonian syndromes, exceeding the reduction in PD. The dopaminergic degeneration in PD appears to slow down during the course of the disease. SPECT with [123I]beta-CIT is a sensitive marker of disease progression in parkinsonian disorders.
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PMID:Progression of dopaminergic degeneration in Parkinson's disease and atypical parkinsonism: a longitudinal beta-CIT SPECT study. 1183 38

The cognitive (executive) ability of patients with Parkinson's-disease (PD) deteriorates gradually during the progression of the disease. Fluency of speech, word finding, working memory, ability to plan the future and flexibility decline. Cognitive disturbance was found to be proportional with the speech, posture, gait and balance problems and can not be influenced by L-dopa substitution. Apart the dorsal and ventral mesolimbic dopaminergic systems the coerulo-cortical noradrenergic, serotoninergic and cholinergic systems are also impaired in PD. Subcortical dementia in PD can also be explained by the functional disability of dorsolateral and anterior cingular circuits. Attention deficit can be explained by the dopamine depletion of cingular cortex. Cortical Lewy bodies, neurofibrillary tangles, neurit plaques and additional vascular pathology should also play a role in cognitive impairment of PD. In several systemic degenerative diseases associating with Parkinson's syndrome (PS) i.e. progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), multiple system atrophy (MSA) dementia can be detected with various severity, therefore the question arises concerning the correlation between cognitive disability and PS. Parkinson syndrome can also develop in frontotemporal dementias (FTD), Alzheimer's disease and cortical Lewy body disease (CLBD) but no correlation exists between motor disability and severity of dementia. In CLBD dementia can be the initial symptom in 18% of cases but PS can also preceeds the dementia. In PSP profound depletion of other monoaminergic neurotransmitter system was also reported. In FTDs associated with PS degeneration of substantia nigra, locus coeruleus and basal nucleus of Meynert has been reported with increased number of neurofibrillary tangles. In patients with vascular PS (VP) there is generally no tremor and rigidity, but pseudobulbar palsy, dementia, gate disturbance, incontinency appears; L-dopa treatment is generally ineffective. In VP no cellular loss can be found within the substantia nigra, but leukoaraiosis, lacunae in the white matter and basal ganglia are commonly demonstrated.
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PMID:[Parkinson syndrome and cognitive disorders]. 1220 Dec 29

Parkinson's disease (PD) was noted to have a familial component as early as 1880 (Leroux, 1880). More recently, the discovery of several genetic factors influencing parkinsonism has emphasized the importance of heredity in PD. The clinical spectrum of familial parkinsonism is wide; it includes not only PD, but also dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), essential tremor, and other disorders. In the general population, it is likely that PD results from combined genetic and environmental factors, most of which are not yet known. The discovery of causal mutations in the gene for alpha-synuclein, parkin, and of genetic linkages to chromosomes 2p4, 4p5, and three loci on 1q6-8 have revolutionized PD research. This review focuses on recent progress in the Mendelian genetics of PD and those diseases in which parkinsonism is a prominent feature, and considers how these discoveries modify our beliefs regarding the etiology and pathogenesis of these disorders.
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PMID:Genetics of parkinsonism. 1221 Aug 52

The study aimed to compare olfactory function in idiopathic Parkinson's disease (IPD) and nonidiopathic Parkinson's syndrome (PS). At their first visit 50 PS patients (age 38-80 years) received testing for odor threshold, olfactory discrimination and identification. All patients underwent extensive neurological diagnostics including PET scans. Patients were followed up for 6-12 months. Most of IPD patients were functionally anosmic (n=19), the remaining IPD patients had severe/moderate hyposmia (n=18). PS patients diagnosed with multiple system atrophy had less severe olfactory deficits (7 hyposmia, 1 normosmia). With the exception of 1 hyposmic patient, other PS patients had no olfactory deficits (progressive supranuclear palsy, corticobasal degeneration, psychogenic PS, essential tremor). This study added to previous findings: (1) there was no major difference betwesen olfactory function in IPD subtypes; (2) all olfactory tests differentiated IPD from nonIPD. These data suggest that olfactory probes improve the diagnostic armamentarium in IPD.
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PMID:Olfactory function in Parkinsonian syndromes. 1238 7

Movement disorders, including Parkinson's disease and parkinsonian syndromes, e.g. progressive supranuclear palsy, multiple system atrophy, and Lewy body dementia, may be difficult to differentiate among each other at an early stage, since they may share similar clinical features and response to dopaminergic drugs. As new tracers for imaging the dopamine transporters become available, the use of positron emission tomography (PET) for the differential diagnosis of movement disorders is gaining clinical relevance. Visual interpretation is generally used for PET image analysis. However, the use of some form of less subjective analysis is desirable in order to detect subtle changes that may be difficult to identify by visual interpretation and to achieve an operator independent analysis. To this end this study was aimed at assessing the feasibility of using statistical parametric mapping (SPM) for the clinical evaluation of single PET scans performed with 2-beta-carbomethoxy-3-beta-(4-fluorophenyl)-tropane ( C-beta-CIT-FE). Eleven healthy volunteers and five patients with movement disorders (Parkinson's disease, essential tremor, PSP and Lewy body dementia) were included in this study. Each subject underwent a PET study after i.v. injection of C-beta-CIT-FE. The PET images of C-beta-CIT-FE distribution acquired between 60 and 90 min were spatially fitted into the Talairach and Tournoux space. A template of normal C-beta-CIT-FE distribution was derived from studies in the 11 normal control subjects. Different patterns of reduction of the uptake of the tracer were detected in the basal ganglia of the five patients, in relation to each pathological condition. The patterns of distribution were all consistent with the severity and type of disease. The results of this study demonstrate the feasibility of differentiating among different states of dopaminergic impairment, due to Parkinson's disease and parkinsonian syndromes, by using PET scans with C-beta-CIT-FE and by using the SPM procedure for analysis of the data.
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PMID:The feasibility of statistical parametric mapping for the analysis of positron emission tomography studies using 11C-2-beta-carbomethoxy-3-beta-(4-fluorophenyl)-tropane in patients with movement disorders. 1241 32


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