| 1. |
- Björkman, Anders, et al.
(författare)
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Cortical sensory and motor response in a patient whose hand has been replanted: One-year follow up with functional magnetic resonance imaging
- 2007
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Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - : Informa UK Limited. - 1651-2073 .- 0284-4311. ; 41:2, s. 70-76
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Tidskriftsartikel (refereegranskat)abstract
- Functional magnetic resonance imaging (fMRI) was used to study how a replanted hand regained its cortical territory parallel to recovery. The cortical response to sensory stimulation shifts from an ipsilateral to a bilateral pattern, and then to a predominantly contralateral activation. The cortical response to motor stimulation was normal from the first investigation.
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| 2. |
- Fuchs, J, et al.
(författare)
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Phenotypic variation in a large Swedish pedigree due to SNCA duplication and triplication.
- 2007
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Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 1526-632X .- 0028-3878. ; 68:12, s. 916-922
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Tidskriftsartikel (refereegranskat)abstract
- Background: The " Lister family complex," an extensive Swedish family with autosomal dominant Parkinson disease, was first described by Henry Mjones in 1949. On the basis of clinical, molecular, and genealogic findings on a Swedish and an American family branch, we provide genetic evidence that explains the parkinsonism in this extended pedigree. Methods: Clinical methods included a detailed neurologic exam of the proband of the Swedish family branch, MRI, and ([ 123] I) - beta - CIT SPECT imaging. Genomic analysis included alpha-synuclein sequencing, SNCA real-time PCR dosage, chromosome 4q21 microsatellite analysis, and high-resolution microarray genotyping. The geographic origin and ancestral genealogy of each pedigree were researched in the medical literature and Swedish Parish records. Results: The proband of the Swedish family branch presented with early dysautonomia followed by progressive parkinsonism suggestive of multiple system atrophy. Molecular analysis identified a genomic duplication of < 0.9 Mb encompassing alpha-synuclein and multimerin 1 ( SNCA- MMRN1), flanked by long interspersed repeat sequences ( LINE L1). Microsatellite variability within the genomic interval was identical to that previously described for a Swedish American family with an alpha- synuclein triplication. Subsequent genealogic investigation suggested that both kindreds are ancestrally related to the Lister family complex. Conclusion: Our findings extend clinical, genetic, and genealogical research on the Lister family complex. The genetic basis for familial parkinsonism is an SNCA- MMRN11 multiplication, but whereas SNCA- MMRN1 duplication in the Swedish proband ( Branch J) leads to late- onset autonomic dysfunction and parkinsonism, SNCA- MMRN1 triplication in the Swedish American family ( Branch I) leads to early- onset Parkinson disease and dementia.
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| 3. |
- Knutsson, Linda, et al.
(författare)
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Absolute quantification of cerebral blood flow in normal volunteers: Correlation between Xe-133SPECT and dynamic susceptibility contrast MRI
- 2007
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1522-2586 .- 1053-1807. ; 26:4, s. 913-920
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare, absolute cerebral blood flow (CBF) estimates obtained by dynamic susceptibility contrast MRI (DSC-MRI) and Xe-133 SPECT. Materials and Methods: CBF was measured in 20 healthy volunteers using DSC-MRI at 3T and Xe-133 SPECT. DSC- MRI was accomplished by gradient-echo EPI and CBF was calculated using a time-shift-insenisitive deconvolution algorithm and regional arterial input functions (AIFs). To improve the reproducibility of AIF registration the time integral was rescaled by use, of a venous output function. In the Xe-133 SPECT experiment, Xe-133 gas was inhaled over 8 minutes and CBF was calculated using a biexponential analysis. Results: The average whole-brain CBF estimates obtained by DSC-MRI and Xe- 133 SPECT were 85 +/- 23 mL/(min 100 g) and 40 +/- 8 mL/(min 100 g), respectively (mean +/- SD, n = 20). The linear CBF relationship between the two modalities showed a correlation coefficient of r = 0.76 and was described by the equation CBF(MRI) = 2.4 CBF(Xe) - 7.9 (CBF in units of mL/(min 100 g)). Conclusion: A reasonable positive linear correlation between MRI-based and SPECT-based CBF estimates was observed after AIF time-integral correction. The use of DSC-MRI typically results in overestimated absolute perfusion estimates and the present study indicates that this trend is further enhanced by the use of high magnetic field strength (3T).
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| 4. |
- Nilsson, Christer, et al.
(författare)
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Tracking the neurodegeneration of parkinsonian disorders - A pilot study
- 2007
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Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 1432-1920 .- 0028-3940. ; 49:2, s. 111-119
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to explore the possibilities of using diffusion tensor imaging (DTI) and tractography (DTT) for the differential diagnosis and monitoring of disease progression in idiopathic Parkinson's disease (IPD), compared with the atypical parkinsonian disorders multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). A 3.0-T MR scanner was used. DTI was acquired using a single-shot EPI sequence with diffusion encoding in 32 directions and a voxel size of 2×2×2 mm3. DTI data were analysed and DTT was performed using the PRIDE fibre tracking tool supplied by the manufacturer. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) within each tract were determined. DTI and DTT images in patients with moderate to advanced MSA demonstrated degeneration of the middle cerebellar peduncles and pontine crossing tracts, with decreased FA and increased ADC. This accounted for most of the pontine and cerebellar atrophy characteristic of this disease. In contrast, patients with PSP showed a selective degeneration of the superior cerebellar peduncle. Three-dimensional images of whole-brain white matter tracts demonstrated a reduction of cortical projection fibres in all patients with PSP. Visualization of the selective degeneration of individual fibre tracts, using DTI and DTT, adds qualitative data facilitating the differential diagnosis of parkinsonian disorders. Repeated measurements of FA and ADC values in a whole fibre tract might be used for monitoring disease progression and studying the effect of treatment in neuroprotective trials. The results are preliminary considering the small number of subjects in the study. © Springer-Verlag 2007.
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| 5. |
- Wirestam, Ronnie, et al.
(författare)
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Attempts to improve absolute quantification of cerebral blood flow in dynamic susceptibility contrast magnetic resonance imaging: a simplified t1-weighted steady-state cerebral blood volume approach.
- 2007
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Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 48:5, s. 550-556
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Tidskriftsartikel (refereegranskat)abstract
- Background: Attempts to retrieve absolute values of cerebral blood flow (CBF) by dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) have typically resulted in overestimations. Purpose: To improve DSC-MRI CBF estimates by calibrating the DSC-MRI-based cerebral blood volume (CBV) with a corresponding T1-weighted (T1W) steady-state ( ss) CBV estimate. Material and Methods: 17 volunteers were investigated by DSC-MRI and Xe-133 SPECT. Steady-state CBV calculation, assuming no water exchange, was accomplished using signal values from blood and tissue, before and after contrast agent, obtained by T1W spin-echo imaging. Using steady-state and DSC-MRI CBV estimates, a calibration factor K=CBV(ss)/CBV(DSC) was obtained for each individual. Average whole-brain CBF( DSC) was calculated, and the corrected MRI-based CBF estimate was given by CBF(ss)=KxCBF(DSC). Results: Average whole-brain SPECT CBF was 40.1 +/- 6.9 ml/min . 100 g, while the corresponding uncorrected DSC-MRI- based value was 69.2 +/- 13.8 ml/min . 100 g. After correction with the calibration factor, a CBF( ss) of 42.7 +/- 14.0 ml/min . 100 g was obtained. The linear fit to CBF( ss)-versus-CBF( SPECT) data was close to proportionality (R=0.52). Conclusion: Calibration by steady-state CBV reduced the population average CBF to a reasonable level, and a modest linear correlation with the reference Xe-133 SPECT technique was observed. Possible explanations for the limited accuracy are, for example, large-vessel partial-volume effects, low post-contrast signal enhancement in T1W images, and water-exchange effects.
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