Walter Pirker

During the past decade, dopamine transporter (DAT) imaging with single photon emission computerized tomography (SPECT) or positron emission tomography (PET) has evolved as an objective in vivo marker of nigrostriatal neuron loss in Parkinson's disease (PD). We investigate the relationship between striatal DAT binding, measured with [¹²³I]β‐CIT SPECT, and parkinsonian motor handicap in a sample of 59 PD patients with minimal to severe disability, and review published cross‐sectional studies on the correlation between DAT imaging and motor symptoms in PD. Earlier studies as well as the present results show a good correlation between overall striatal DAT binding and global measures of disease severity such as the Hoehn and Yahr scale, the total score on the Unified Parkinson's Disease Rating Scale (UPDRS), and UPDRS activities of daily living, with a progressive decline of DAT binding with increasing disability. A number of studies found a significant inverse correlation of striatal DAT binding with UPDRS motor score. Bradykinesia, posture, gait, and other midline symptoms, such as speech and facial expression, compared with rigidity, seem to be more closely related to striatal DAT binding. By contrast, neither the severity of parkinsonian rest nor of action tremor is related to the degree of dopaminergic denervation as measured by DAT imaging. Motor symptoms in the clinically less affected body side show a closer correlation with striatal DAT binding than do symptoms occurring in the dominantly affected body side. The correlation of putamen and caudate DAT binding with parkinsonian motor handicap seems to be similar. Although there have been limited comparative studies applying [¹⁸F]fluorodopa PET and DAT imaging in the same group of PD patients, available data suggest that putamen [¹⁸F]fluorodopa uptake, when compared with striatal DAT binding, may be more closely related to parkinsonian motor handicap. © 2003 Movement Disorder Society

Recent imaging studies suggest a rapid degeneration of the dopaminergic system in early Parkinson's disease (PD), followed by a slowing of the degenerative process in advanced disease. In the present study, a group of early‐stage PD patients underwent three sequential [¹²³I]β‐CIT SPECT studies to assess the decline of striatal dopamine transporter binding over a 5‐year period. Twenty‐one of a cohort of 24 early PD patients who participated in an earlier longitudinal β‐CIT SPECT imaging study [Mov Disord 2002;17:45–53] were included. Scan intervals were 26 ± 11 months (scan 1–2) and 38 ± 15 months (scan 2–3), respectively. The relative annual rate of decline of striatal β‐CIT binding from age‐expected normal values at the time of Scan 1 was used as primary outcome variable. The relative annual decline of striatal binding from Scan 1 to Scan 2 (4.5 ± 4.6%) and from Scan 2 to Scan 3 (3.0 ± 3.0%) was not significantly different. The non‐significant difference in progression rate was due mainly to the rapid early decline of striatal binding in 1 patient who subsequently developed a severe dysexecutive dementia syndrome. These data are not suggestive of substantial change in the course of dopaminergic degeneration in PD within the first 5 to 7 years after symptom onset. © 2003 Movement Disorder Society

We report on a patient with spinocerebellar ataxia type 2 (SCA 2) with an unusual clinical presentation, including severe, disabling resting and action tremor and the successful treatment of this tremor syndrome with chronic thalamic stimulation. Using [¹²³I]β‐CIT single photon emission computed tomography, we document a marked degeneration of the nigrostriatal dopaminergic system in SCA 2. © 2002 Movement Disorder Society

We investigated whether [ ¹²³ I]‐β‐CIT and single‐photon emission computed tomography (SPECT) imaging distinguishes patients with clinically suspected vascular parkinsonism (VP) from patients with idiopathic Parkinson's disease (PD). [ ¹²³ I]β‐CIT SPECT is a sensitive marker of dopaminergic degeneration, and the degree of striatal binding reduction in PD correlates with disease severity. Thirteen patients who fulfilled rigid clinical criteria for VP (mean ± S.D.: age, 76.5 ± 5.3 years; disease duration, 3.6 ± 2.8 years), 20 PD patients (age, 66.2 ± 9.5 years; disease duration, 4.3 ± 2.7 years), and 30 healthy persons (age, 44.6 ± 19.2 years) underwent [ ¹²³ I]β‐CIT SPECT imaging. Age‐corrected striatal β‐CIT binding was reduced on average by 40.8% in PD but was near normal in the VP group (mean reduction, 1.2%). This difference was statistically significant ( Z = 4.68; P < 0.001). The left–right asymmetry of striatal β‐CIT binding was significantly increased in the PD group compared with normal controls and the VP group (F(2) = 17.4, P P < 0.001). Whole striatal β‐CIT binding was more than one standard deviation above the mean PD values in all but one of the individual VP patients. Our findings suggest that the presynaptic dopaminergic deficits seen in PD are absent in most patients with VP. [ ¹²³ I]β‐CIT SPECT imaging may be useful to help distinguish between PD and VP patients during life. © 2002 Movement Disorder Society

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]β‐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]β‐CIT SPECT imaging with an interval of 25.5 ± 10.3 (13–63) months. The age‐related decline of striatal β‐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 β‐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 β‐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 β‐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 β‐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]β‐CIT is a sensitive marker of disease progression in parkinsonian disorders. © 2001 Movement Disorder Society.