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  • 1
    Electronic Resource
    Electronic Resource
    Effects of aging on the cerebral distribution of technetium-99m hexamethylpropylene amine oxime in healthy humans (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 754-761 
    Details
    ISSN: 1619-7089
    Keywords: Aging ; Regional cerebral blood flow ; Single-photon emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Some brain functions decline at a linear rate throughout adulthood. Others remain relatively stable until very late in the life cycle. This study characterized the effects of aging on the regional cerebral distribution of hexamethylpropylene amine oxime (HMPAO) in healthy human volunteers. The sample consisted of 26 men and 18 women with a mean age of 41.6±14.9 years (range: 19–73). Their past medical histories, physical examinations, and laboratory screening tests were normal. Single-photon emission tomography (SPET) scans of the brain were performed with a standardized acquisition and processing protocol on a triple-headed camera equipped with fan beam collimators. A 3-D restorative filter and a correction for uniform attenuation were applied before the images were reinterpolated in planes parallel to the line connecting the frontal and occipital poles. Mean counts per pixel were measured in multiple regions of interest (ROIs) within each hemisphere by custom fitting a set of templates to the images. The mean activity in each ROI was compared with the mean activity per pixel in the whole brain. Regression analyses were used to relate the activity ratios to age with both linear and nonlinear models. The relative concentration of radioactivity decreased significantly with age in most, but not all, gray matter structures. It increased in the white matter regions. The nonlinear model of aging fit the data significantly better than a straight line did. Most of the changes with age occurred during young adulthood. No further changes were detectable after the onset of middle age. The median breakpoint age at which the rate of change became negligible was 36.6 years. Aging significantly affects the relative uptake of HMPAO in healthy humans. It decreases in many gray matter regions and increases in most white matter regions. However, the changes do not appear to be linear. Most seem to occur during young adulthood before people reach their late thirties. The distribution then appears to remain relatively stable throughout middle age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00879663
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Simplified reference region model for the kinetic analysis of [99mTc]TRODAT-1 binding to dopamine transporters in nonhuman primates using single-photon emission tomography (1999)
    Springer
    European journal of nuclear medicine 26 (1999), S. 518-526 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Dopamine transporters ; Kinetic modeling ; Single-photon emission tomography ; Striatum ; Technetium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Accurate quantification of neuroreceptors requires full kinetic modeling of the dynamic single-photon emission tomography (SPET) or positron emission tomography (PET) images, with highly invasive arterial blood sampling. This study investigated the application of a reference region kinetic model to the dynamics of [99mTc]TRODAT-1 in nonhuman primates, obviating the need for blood sampling. A series of dynamic SPET scans were performed on two baboons following the injection of approximately 700 MBq of [99mTc]TRODAT-1. Rapid arterial blood samples were taken automatically during scanning. Reconstructed SPET images were co-registered with magnetic resonance imaging (MRI) scans of the baboons, and regions of interest (ROIs) placed on the striatum, cerebellum and cerebral hemispheres. The ROI data were combined with metabolite-corrected blood data, and fitted to a three-compartment kinetic model using nonlinear least squares techniques. The same data were also used in a simplified reference region model, in which the input function was derived from the nondisplaceable tissue compartment. In addition, semiquantitative blinded analysis was performed by three raters to determine the point of transient equilibrium in the specific binding curves. All methods generated values for the ratio of the kinetic rate constants k 3 /k 4, which gives an estimate of the binding potential, BP. These were compared with the full kinetic model. The mean values of k 3 /k 4 for the three different analysis techniques for each baboon were: 1.17±0.21 and 1.12±0.13 (full kinetic model), 0.93±0.13 and 0.90±0.07 (reference region model), and 0.97±0.18 and 0.92±0.08 (equilibrium method). The reference region method gave significantly lower results than the full kinetic model (P = 0.01), but it also produced a much smaller spread and better quality fits to the kinetic data. The reference region model results for k 3 /k 4 correlated very strongly with the full kinetic analysis (r 2 = 0.992, P〈0.001), and with the equilibrium model (r 2 = 0.88, P = 0.002). The subjectivity inherent in the equilibrium method produces inferior results compared with both kinetic analyses. It is suggested that the self-consistency of the reference region model, which requires no arterial blood sampling, provides a more precise and reliable estimate of the binding of [99mTc]TRODAT-1 to dopamine transporters than full kinetic modeling. The reference region method is also better suited to a routine clinical environment, and would be able to distinguish smaller differences in dopaminergic function between patient groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590050420
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Logistic discriminant parametric mapping: a novel method for the pixel-based differential diagnosis of Parkinson’s disease (1999)
    Springer
    European journal of nuclear medicine 26 (1999), S. 1413-1423 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Discriminant analysis ; Parkinson’s disease ; Dopamine transporter ; Single-photon emission tomography ; Statistical parametric mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Positron emission tomography (PET) and single-photon emission tomography (SPET) imaging of the dopaminergic system is a powerful tool for distinguishing groups of patients with neurodegenerative disorders, such as Parkinson’s disease (PD). However, the differential diagnosis of individual subjects presenting early in the progress of the disease is much more difficult, particularly using region-of-interest analysis where small localized differences between subjects are diluted. In this paper we present a novel pixel-based technique using logistic discriminant analysis to distinguish between a group of PD patients and age-matched healthy controls. Simulated images of an anthropomorphic head phantom were used to test the sensitivity of the technique to striatal lesions of known size. The methodology was applied to real clinical SPET images of binding of technetium-99m labelled TRODAT-1 to dopamine transporters in PD patients (n=42) and age-matched controls (n=23). The discriminant model was trained on a subset (n=17) of patients for whom the diagnosis was unequivocal. Logistic discriminant parametric maps were obtained for all subjects, showing the probability distribution of pixels classified as being consistent with PD. The probability maps were corrected for correlated multiple comparisons assuming an isotropic Gaussian point spread function. Simulated lesion sizes measured by logistic discriminant parametric mapping (LDPM) gave strong correlations with the known data (r 2=0.985, P〈0.001). LDPM correctly classified all PD patients (sensitivity 100%) and only misclassified one control (specificity 95%). All patients who had equivocal clinical symptoms associated with early onset PD (n=4) were correctly assigned to the patient group. Statistical parametric mapping (SPM) had a sensitivity of only 24% on the same patient group. LDPM is a powerful pixel-based tool for the differential diagnosis of patients with PD and healthy controls. The diagnosis of disease even before clinical symptoms become apparent may be possible, and ultimately this technique could be most useful in differentiating between several neurodegenerative disorders, incorporating images of multiple neuroreceptor systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590050473
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Simplified quantification of dopamine transporters in humans using [99mTc]TRODAT-1 and single-photon emission tomography (2000)
    Springer
    European journal of nuclear medicine 27 (2000), S. 1714-1718 
    Details
    ISSN: 1619-7089
    Keywords: Dopamine transporters Kinetic modeling Single-photon emission tomography Striatum Graphical analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Quantification of dopamine transporters (DAT) using [99mTc]TRODAT-1 and single-photon emission tomography (SPET) requires full kinetic modeling of the data, using complex and invasive arterial blood sampling to provide an input function to the model. We have shown previously that a simpler reference tissue model provides accurate quantitative results, using a reference region devoid of DAT as the input to the model and thereby obviating the need for blood sampling. We now extend this work into humans, and develop further simplifications to make the imaging protocol much more practical as a routine procedure. Fourteen healthy subjects (age 29.8±8.4 years, range 18.7–45.5 years) underwent dynamic SPET for 6 h following injection of 752±28 MBq [99mTc]TRODAT-1. The kinetic data were analyzed using nonlinear regression analysis (NLRA) and Logan-Patlak graphical analysis. In addition, simple average ratios of striatal-to-background counts were obtained for three 1-h periods (3–4 h, 4–5 h, 5–6 h), and compared against the kinetic models. All methods gave an index of specific binding, proportional to the binding potential, known as the distribution volume ratio (DVR). The reference tissue NLRA gave mean values of k 3=0.013±0.003 min–1, k 4=0.011±0.002 min–1, and DVR=2.29±0.17. Graphical analysis gave a value of DVR=2.28±0.16, and the three ratio values of DVR were: 3–4 h, 2.18±0.15; 4–5 h, 2.34±0.13; and 5–6 h, 2.46±0.19. Graphical analysis was highly correlated with NLRA (R 2=0.91, slope=0.90±0.08). The ratio methods correlated well with NLRA (3–4 h, R 2=0.71, slope=0.73±0.13; 4–5 h, R 2=0.86, slope=0.73±0.09; 5–6 h, R 2=0.80, slope=1.00±0.15), and also with graphical analysis (3–4 h, R 2=0.65, slope=0.74±0.16; 4–5 h, R 2=0.85, slope=0.78±0.09; 5–6 h, R 2=0.88, slope=1.11±0.12). The optimum equilibrium time point for obtaining a simple ratio was approximately 4.5–5.5 h. In conclusion, the simple ratio techniques for obtaining a quantitative measure of specific binding correlated well with the reference tissue kinetic models, using both NLRA and graphical analysis. The optimum time for obtaining a ratio appeared to be in the range 4.5–5.5 h. Earlier time points, while still relatively accurate, had a lower sensitivity and may not be optimized for measuring small changes in DAT concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590000371
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Relationship between clinical features of Parkinson’s disease and presynaptic dopamine transporter binding assessed with [123I]IPT and single-photon emission tomography (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 415-421 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Dopamine transporter ; Cocaine analogues ; Single-photon emission tomography ; Parkinson’s disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. IPT [N-(3-iodopropen-2-yl)-2β-carbomethoxy-3β-(4-chlorophenyl) tropane] is a new cocain analogue which allows the presynaptic dopamine transporters to be imaged with single-photon emission tomography (SPET) as early as 1–2 h post injection. In the present study [123I]IPT SPET was performed in patients with Parkinson’s disease (PD) to analyse the relationship between specific dopamine tansporter binding and clinical features of the disease. Twenty-six PD patients (Hoehn and Yahr stages I–IV, age range 40–79 years) and eight age-matched controls were studied. SPET imaging was performed 90–120 min after injection of 160–185 MBq [123I]IPT using a triple-head camera. For semiquantitative evaluation of specific [123I]IPT binding, ratios between caudate, putamen and background regions were calculated. Specific [123I]IPT uptake was significantly reduced in PD patients compared to controls. Most patients showed a marked asymmetry with a more pronounced decrease in [123I]IPT binding on the side contralateral to the predominant clinical findings. The putamen was always more affected than the caudate. [123I]IPT binding was significantly correlated with disease duration (r=−0.7, P〈0.0001) but not with the age of PD patients (r=−0.10, P=0.61). Specific [123I]IPT uptake in the caudate and putamen, and putamen to caudate ratios, decreased with increasing Hoehn and Yahr stage. Our findings indicate that [123I]IPT SPET may be a useful technique to estimate the extent of nigrostriatal degeneration in PD patients. Close relationships between striatal [123I]IPT binding and clinical features of the disease suggest that this method can be used to objectively follow the course and progression of PD. The reduced putamen to caudate ratios observed even in patients with mild, newly recognized symptoms indicate that particularly this parameter may help to establish the correct diagnosis in the early course of PD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00881814
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Relationship between clinical features of Parkinson's disease and presynaptic dopamine transporter binding assessed with [123I]IPT and single-photon emission tomography (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 415-421 
    Details
    ISSN: 1619-7089
    Keywords: Dopamine transporter ; Cocaine analogues ; Single-photon emission tomography ; Parkinson's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract IPT [N-(3-iodopropen-2-yl)-2β-carbome-thoxy-3β-(4-chlorophenyl) tropane] is a new cocain analogue which allows the presynaptic dopamine transporters to be imaged with single-photon emission tomography (SPET) as early as 1–2 h post injection. In the present study [123I]IPT SPET was performed in patients with Parkinson's disease (PD) to analyse the relationship between specific dopamine tansporter binding and clinical features of the disease. Twenty-six PD patients (Hoehn and Yahr stages I-IV, age range 40–79 years) and eight age-matched controls were studied. SPET imaging was performed 90–120 min after injection of 160–185 MBq [123I]IPT using a triple-head camera. For semiquantitative evaluation of specific [123I]IPT binding, ratios between caudate, putamen and background regions were calculated. Specific [123I]IPT uptake was significantly reduced in PD patients compared to controls. Most patients showed a marked asymmetry with a more pronounced decrease in [123I]IPT binding on the side contralateral to the predominant clinical findings. The putamen was always more affected than the caudate. [123I]IPT binding was significantly correlated with disease duration (r=−0.7,P〈0.0001) but not with the age of PD patients (r=−0.10,P=0.61). Specific [123I]IPT uptake in the caudate and putamen, and putamen to caudate ratios, decreased with increasing Hoehn and Yahr stage. Our findings indicate that [123I]IPT SPET may be a useful technique to estimate the extent of nigrostriatal degeneration in PD patients. Close relationships between striatal [123I]IPT binding and clinical features of the disease suggest that this method can be used to objectively follow the course and progression of PD. The reduced putamen to caudate ratios observed even in patients with mild, newly recognized symptoms indicate that particularly this parameter may help to establish the correct diagnosis in the early course of PD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00881814
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Effects of aging on the cerebral distribution of technetium-99m hexamethylpropylene amine oxime in healthy humans (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 754-761 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Aging ; Regional cerebral blood flow ; Single-photon emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Some brain functions decline at a linear rate throughout adulthood. Others remain relatively stable until very late in the life cycle. This study characterized the effects of aging on the regional cerebral distribution of hexamethylpropylene amine oxime (HMPAO) in healthy human volunteers. The sample consisted of 26 men and 18 women with a mean age of 41.6±14.9 years (range: 19–73). Their past medical histories, physical examinations, and laboratory screening tests were normal. Single-photon emission tomography (SPET) scans of the brain were performed with a standardized acquisition and processing protocol on a triple-headed camera equipped with fan beam collimators. A 3-D restorative filter and a correction for uniform attenuation were applied before the images were reinterpolated in planes parallel to the line connecting the frontal and occipital poles. Mean counts per pixel were measured in multiple regions of interest (ROIs) within each hemisphere by custom fitting a set of templates to the images. The mean activity in each ROI was compared with the mean activity per pixel in the whole brain. Regression analyses were used to relate the activity ratios to age with both linear and nonlinear models. The relative concentration of radioactivity decreased significantly with age in most, but not all, gray matter structures. It increased in the white matter regions. The nonlinear model of aging fit the data significantly better than a straight line did. Most of the changes with age occurred during young adulthood. No further changes were detectable after the onset of middle age. The median breakpoint age at which the rate of change became negligible was 36.6 years. Aging significantly affects the relative uptake of HMPAO in healthy humans. It decreases in many gray matter regions and increases in most white matter regions. However, the changes do not appear to be linear. Most seem to occur during young adulthood before people reach their late thirties. The distribution then appears to remain relatively stable throughout middle age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00879663
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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