| 1. |
- Englund, E., et al.
(författare)
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Tumours of the central nervous system. Proton magnetic resonance relaxation times T1 and T2 and histopathologic correlates
- 1986
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Ingår i: Acta Radiologica Diagnosis. - : SAGE Publications. - 0567-8056. ; 27:6, s. 653-659
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Tidskriftsartikel (refereegranskat)abstract
- Proton MR relaxation times T1 and T2 were determined in vitro in 136 small specimens of astrocytomas grades I-IV, of oligodendrogliomas, metastases of adenocarcinomas, meningiomas and acoustic neuromas. In addition, 7 samples of peritumoural white matter were analysed. The analysed specimens were studied microscopically in their entirety regarding tumour type and occurrence of necrosis and non-tumour tissue admixture, such as fibrosis and haemorrhage. Most of the gliomas had longer relaxation times than normal white matter and T2 was significantly longer than in the other three tumour groups. The metastases had longer T1 than normal white matter, while T2 varied. The astrocytomas tended to show shorter relaxation times with increasing degree of malignancy, and shortening of T1 and T2 correlating with the proportion of tissue necrosis. Similarly, the metastases with tissue necrosis had shorter T1 and T2 than non-necrotic samples. The meningiomas had T1 values comparable with normal cortex, while the T2 values varied. Tumours containing a large proportion of fibrous tissue had shorter relaxation times than the others. Acoustic neuromas had only slightly longer T1 than normal white matter, while T2 was not prolonged. Both T1 and T2 were significantly shorter than in all other tumours studied. Peritumoural white matter had prolonged relaxation times compared with normal white matter, correlating to increased water content. These in vitro differences regarding relaxation times in various types of tumours of the central nervous system, dependent on various types of tissue alterations, should be of interest for the interpretation of in vivo images.
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| 2. |
- Györffy-Wagner, Z., et al.
(författare)
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Proton magnetic resonance relaxation times T1 and T2 related to postmortem interval : An Investigation on Porcine Brain Tissue
- 1986
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 0567-8056. ; 27:1, s. 115-118
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Forskningsöversikt (refereegranskat)abstract
- In order to establish the validity of in vitro determination of the proton magnetic resonance (MR) relaxation times T1 and T2 in brain tissue at increasing time delay after death or operative excision, 81 brain tissue samples from 23 pigs were analyzed repeatedly. These samples, representing cortex, caudate nucleus and white matter, were studied microscopically after MR measurements. The T1 values exhibited no time dependence and the T2 values decreased slightly during the interval 2 to 90 hours after death. The samples were stored at +8°C between the measurements. These results indicate that reliable in vitro measurements can be obtained in autopsy or surgical brain tissue specimens within 90 hours after death or excision, if handled properly.
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| 3. |
- Larsson, E. M., et al.
(författare)
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Regional differences in the proton magnetic resonance relaxation times T1 and T2 within the normal human brain
- 1986
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 0567-8056. ; 27:2, s. 231-234
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Forskningsöversikt (refereegranskat)abstract
- The proton magnetic resonance (MR) relaxation times T1 and T2 were determined in autopsy specimens from 13 different regions of normal human brains. One hundred and seventy-four tissue samples from 25 brains were examined in a pulsed MR analyzer of 0.25 T and were then also studied histologically. There were regional differences in T1 and T2 within the cerebral gray matter but not within the white matter. These regional differences might reflect the different composition and cytoarchitectonic structure of the cortical regions and should be taken into consideration in the interpretation of cortical lesions on MR images.
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| 4. |
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| 5. |
- Brun, A, et al.
(författare)
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Brain changes in dementia of Alzheimer's type relevant to new imaging diagnostic methods
- 1986
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Ingår i: Progress in Neuro-Psychopharmacology and Biological Psychiatry. - : Elsevier BV. - 0278-5846. ; 10:3-5, s. 297-308
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the article is to correlate grey and white matter changes and their topography to the results of modern methods for brain imaging such as CT, rCBF, PET, SPECT and NMR in Alzheimer's type of dementia. The findings are based on the study of a large material investigated thoroughly patho-anatomically. The findings are correlated with psychiatric and neurophysiologic follow-up studies. The degenerative grey matter process shows a regionally varying accent according to a pattern which is consistent and typical for the disease. This corresponds to metabolic changes on rCBF, PET and SPECT and thereby becomes of diagnostic value. This pattern is largely symmetric. Metabolic asymmetries have however been reported on PET scans. In this context individual variations of the topographic degenerative brain pattern and normal anatomical brain asymmetries are of interest. The white matter however also frequently shows changes, in particular loss of myelin and axons and a mild gliosis, slight in 1/3 of the cases and severe in an additional 1/3. These changes cause a decrease of density in the centrum semiovale correlating to lipid depletion. They may also influence the ventricular shape and size, of interest in CT or NMR studies. Also here variations in ventricular shape, normal and such due to pathological processes unrelated to the Alzheimer disease, may cause confusion, regarding degree of atrophy and even type of brain process. Such factors should be considered in the interpretation of non-invasive brain studies.
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| 6. |
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