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  • 1
    Electronic Resource
    Electronic Resource
    Quantitative magnetic resonance analysis in vascular dementia (1997)
    Springer
    Journal of neurology 244 (1997), S. 246-251 
    Details
    ISSN: 1432-1459
    Keywords: Key words Vascular dementia ; Magnetic resonance imaging ; Neuropsychological assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The potential role of magnetic resonance imaging (MRI) in differentiating between specific causes of cognitive decline in patients with vascular dementia (VD) has not yet been fully established. We therefore decided to assess the supratentorial cerebral contents in 24 patients with a diagnosis of probable VD and in 24 normal subjects, matched for age and education level, using MRI volumetric parameters obtained by means of a quantitative method. The volumes of subarachnoid and ventricular spaces, cerebral tissue, and hyperintense areas on T2-weighted images were calculated. In order to reduce interindividual variability caused by differences in intracranial size, each absolute measurement was normalized to the relative size of the intracranial volume. In addition, we calculated the ratio between the areas of the corpus callosum (CC) and supratentorial brain at the same level on the T1-weighted image midsagittal plane. The MRI data were correlated with the deterioration of cognitive functions. Patients with VD showed significantly lower cerebral tissue volume and CC area, and higher ventricular space volume than normal subjects. Furthermore, the total volume of the T2 signal alterations was higher in VD patients than in normal subjects. In VD patients, this volume was found to be proportional to the increase in the volume of the ventricular space. On the other hand, no correlation was found between the volume of the T2 signal alterations and the area of the CC. The degree of global cognitive dysfunction and the score of each neuropsychological test did not show any correlation with the MRI data. Our results suggest that ventricular enlargement in VD patients is correlated with the increase in volume of the T2 signal abnormalities, but that the degree of global cognitive dysfunction is not influenced by the volume of these T2 signal abnormalities. Furthermore, the CC atrophy does not influence the score of any neuropsychological test or the degree of global cognitive dysfunction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004150050079
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Motor stimulation response by technetium-99m hexamethylpropylene amine oxime split-dose method and single photon emission tomography (1992)
    Springer
    European journal of nuclear medicine 19 (1992), S. 939-945 
    Details
    ISSN: 1619-7089
    Keywords: Single photon emission tomography ; Cerebral blood flow ; Technetium-99m hexamethylpropylene amine oxime ; Split-dose method ; Motor activation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We applied the technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) split-dose method in order to evaluate the feasibility of assessing cerebral blood flow (CBF) changes with single photon emission tomography (SPET) during a motor activation task. Eleven normal subjects were studied using the Tomomatic 564 (Medimatic, DK). Five subjects were studied twice at rest and 6 subjects at rest and during a motor task performance (finger opposition movements). A total of 28 mCi of 99mTc-HMPAO was injected in 2 doses with a 1:3 ratio. The first scan was obtained after injection of 7 mCi at rest in all subjects. The second scan was obtained a few minutes later, after injection of the remaining dose (21 mCi), under similar resting conditions or during a motor task performance. The mean brain uptake was proportional to the amount of tracer injected and to the acquisition time for both the first scan (5263±1266 counts × mCi × min) and the second (5034.4±966 counts × mCi × min). The grey/white matter ratio was 1.67±0.019 and 1.67±0.097 for the two scans, respectively. A three-way analysis of variance (ANOVA) for repeated measure showed no significant effects of side, slice and region of interest (ROI) on the CBF in the 5 subjects studied twice at rest, and the mean regional CBF change was −0.2%±5%. In the 6 subjects studied at rest and during motor activation, the image subtraction analysis showed a significant CBF increase in the primary motor cortex contralateral to the stimulated side (15%±7%, n=6) and medially in the supplementary motor area (22%±12%, n=4). Our results indicate that the split-dose method allows the detection of a local CBF response to motor activation using 99mTc-HMPAO in a single imaging session.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175859
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Relationship between thallium-201 uptake by supratentorial glioblastomas and their morphological characteristics on magnetic resonance imaging (1996)
    Springer
    European journal of nuclear medicine 23 (1996), S. 524-529 
    Details
    ISSN: 1619-7089
    Keywords: Thallium-201 single-photon emission tomography ; Magnetic resonance imaging ; Neuro-oncology ; Glioblastoma ; Tumoral necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Single-photon emission tomography (SPET) with thallium-201 is used in the assessment of patients with gliomas because the amount of201Tl accumulated by the tumoral cells increases in proportion to the degree of tumour malignancy, thus making it possible to differentiate high-grade from low-grade gliomas or recurrences from radiation necrosis. However, in large areas of tissue such as those examined in201Tl SPET studies, the uptake of201Tl may vary considerably even in tumours with the same histological diagnosis, as occurs in glioblastomas (GBMs). In order to evaluate the possible influence of the macroscopic characteristics of tumours on201Tl uptake, we studied a series of 13 patients with histologically proven GBMs, comparing magnetic resonance imaging (MRI) parameters such as tumour dimensions, perilesional oedema, intratumoral necrosis and contrast enhancement with the degree of201Tl uptake. The patients underwent both201Tl SPET and MRI before surgery. The201Tl index (tumour/contralateral unaffected brain) was calculated using two different region of interest (ROI) methods: the first employed irregular large ROIs (3.2±13.9 cm2) including pixels with more than 50% maximum activity; the second employed regular square small ROls (2.7 cm2) centered on the maximum activity of the lesion. Of the MRI morphological parameters studied, only necrosis significantly reduced the degree of201Tl uptake in GBMs when larger ROIs were used. However, by using small regular ROIs the influence of necrosis on201Tl uptake was found to be less relevant. Since necrosis is related to tumour proliferative activity and represents a negative prognostic factor in astrocytoma, a possible underestimation of201Tl uptake due to intratumoral necrosis must be carefully evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00833386
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    Paper (German National Licenses)
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