| 1. |
- Kvickstrom, Pia, et al.
(författare)
-
Selective frontal neurodegeneration of the inferior fronto-occipital fasciculus in progressive supranuclear palsy (PSP) demonstrated by diffusion tensor tractography
- 2011
-
Ingår i: BMC Neurology. - : Springer Science and Business Media LLC. - 1471-2377. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The clinical presentation in progressive supranuclear palsy (PSP), an atypical parkinsonian disorder, includes varying degrees of frontal dysexecutive symptoms. Using diffusion tensor imaging (DTI) and tractography (DTT), we investigated whether diffusion changes and atrophy of the inferior fronto-occipital fasciculus (IFO) occurs in PSP and if these changes correlate with disease stage and clinical phenotype. The corticospinal tract (CST), which is often involved in PSP, was investigated for comparison. Methods: DTI of the whole brain was performed with a 3 T MR scanner using a single shot-EPI sequence with diffusion encoding in 48 directions. Scans were obtained in patients with PSP (n = 13) and healthy age-matched controls (n = 12). DTT of the IFO and CST was performed with the PRIDE fibre tracking tool (Philips Medical System). Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated and correlated with disease stage and clinical phenotype. Results: In patients with PSP, significantly decreased FA and increased ADC was found in the frontal part of IFO compared with the medial and occipital parts of IFO, as well as compared to controls. Four of the thirteen patients with PSP showed a marked decrease in the number of tracked voxels in the frontal part of IFO. These findings were most pronounced in patients with severe frontal cognitive symptoms, such as dysexecutive problems, apathy and personality change. There was a strong correlation (r(2) = -0.84; p < 0,001) between disease stage and FA and ADC values in the CST. Conclusions: DTT for identification of neuronal tracts with subsequent measurement of FA and ADC is a useful diagnostic tool for demonstrating patterns of neuronal tract involvement in neurodegenerative disease. In selected tracts, FA and ADC values might act as surrogate markers for disease stage.
|
|
| 2. |
- Looi, Jeffrey C. L., et al.
(författare)
-
Morphometric analysis of subcortical structures in progressive supranuclear palsy: In vivo evidence of neostriatal and mesencephalic atrophy
- 2011
-
Ingår i: Psychiatry Research: Neuroimaging. - : Elsevier BV. - 0925-4927. ; 194:2, s. 163-175
-
Tidskriftsartikel (refereegranskat)abstract
- Progressive supranuclear palsy (PSP) is a neurodegenerative disease characterized by gait and postural disturbance, gaze palsy, apathy, decreased verbal fluency and dysexecutive symptoms, with some of these clinical features potentially having origins in degeneration of frontostriatal circuits and the mesencephalon. This hypothesis was investigated by manual segmentation of the caudate and putamen on MRI scans, using previously published protocols, in 15 subjects with PSP and 15 healthy age-matched controls. Midbrain atrophy was assessed by measurement of mid-sagittal area of the midbrain and pons. Shape analysis of the caudate and putamen was performed using spherical harmonics (SPHARM-PDM, University of North Carolina). The sagittal pons area/midbrain area ratio (P/M ratio) was significantly higher in the PSP group, consistent with previous findings. Significantly smaller striatal volumes were found in the PSP group - putamina were 10% smaller and caudate volumes were 17% smaller than in controls after controlling for age and intracranial volume. Shape analysis revealed significant shape deflation in PSP in the striatum, compared to controls; with regionally significant change relevant to frontostriatal and corticostriatal circuits in the caudate. Thus, in a clinically diagnosed and biomarker-confirmed cohort with early PSP, we demonstrate that neostriatal volume and shape are significantly reduced in vivo. The findings suggest a neostriatal and mesencephalic structural basis for the clinical features of PSP leading to frontostriatal and mesocortical-striatal circuit disruption. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
|
|
| 3. |
- Strandberg, Maria, et al.
(författare)
-
fMRI memory assessment in healthy subjects : a new approach to view lateralization data at an individual level
- 2011
-
Ingår i: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 5:1, s. 1-11
-
Tidskriftsartikel (refereegranskat)abstract
- We present a comprehensive and clinically applicable fMRI test-including both a verbal and a visuospatial task-for assessment of hemispheric specific memory in the medial temporal lobe (MTL). fMRI data was collected from 15 healthy right-handed volunteers. Whole-brain activation was analyzed as well as activation in two regions of interest: the MTL and the anterior speech area. Laterality indices (LI) and LI-curves were calculated using the LI toolbox of Wilke and Lidzba, 2007. The fMRI paradigms successfully visualized memory-related activity in the MTL, the verbal memory measure also provided information of language lateralization. Eleven subjects showed left lateralized verbal encoding in the MTL, visuospatial memory activation was divided equally between left and right, and 14/15 subjects had left lateralized language. Lateralization data at the group level were consistent with previous studies, but a variety of activation effects were found at the individual level indicating differences in strategy during verbal and visuospatial processing. Further studies using the presented method are needed to determine its clinical usefulness.
|
|
| 4. |
- Thordstein, Magnus, et al.
(författare)
-
Transfer of cortical motor representation after a perinatal cerebral insult.
- 2011
-
Ingår i: Pediatric neurology. - : Elsevier BV. - 1873-5150 .- 0887-8994. ; 44:2, s. 131-4
-
Tidskriftsartikel (refereegranskat)abstract
- In a 16-year-old boy with hemiplegia and severe, intractable epilepsy after a neonatal cerebral ischemic insult, cortical motor control was only equivocally assessed by functional magnetic resonance imaging. Therefore, high-precision navigated transcranial magnetic stimulation was performed, which demonstrated that cortical control of muscles on the paretic side was selectively affected. Leg muscle control was located in the contralateral hemisphere, as expected in healthy individuals, whereas forearm muscles were controlled from both hemispheres, and hand muscles were controlled only from the hemisphere ipsilateral to the paresis.
|
|
| 5. |
- van Westen, Danielle, et al.
(författare)
-
Correlation between arterial blood volume obtained by arterial spin labelling and cerebral blood volume in intracranial tumours.
- 2011
-
Ingår i: Magma. - : Springer Science and Business Media LLC. - 1352-8661. ; 24, s. 211-223
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To compare measurements of the arterial blood volume (aBV), a perfusion parameter calculated from arterial spin labelling (ASL), and cerebral blood volume (CBV), calculated from dynamic susceptibility contrast (DSC) MRI. In the clinic, CBV is used for grading of intracranial tumours. MATERIALS AND METHODS: Estimates of aBV from the model-free ASL technique quantitative STAR labelling of arterial regions (QUASAR) experiment and of DSC-CBV were obtained at 3T in ten patients with eleven tumours (three grade III gliomas, four glioblastomas and four meningiomas, two in one patient). Parametric values of aBV and CBV were determined in the tumour as well as in normal grey matter (GM), and tumour-to-GM aBV and CBV ratios were calculated. RESULTS: In a 4-pixel ROI representing maximal tumour values, the coefficient of determination R (2) was 0.61 for the comparison of ASL-based aBV tumour-to-GM ratios and DSC-MRI-based CBV tumour-to-GM ratios and 0.29 for the comparison of parametric values of ASL-aBV and DSC-CBV, under the assumption of proportionality. Both aBV and CBV showed a non-significant tendency to increase when going from grade III gliomas to glioblastomas to meningiomas. CONCLUSION: These results suggest that measurement of aBV is a potential tool for non-invasive assessment of blood volume in intracranial tumours.
|
|
| 6. |
- van Westen, Danielle, et al.
(författare)
-
Magnetic Resonance Findings in the Pregeniculate Visual Pathways in Leber Hereditary Optic Neuropathy.
- 2011
-
Ingår i: Journal of Neuro-Ophthalmology. - 1070-8022. ; 31, s. 48-51
-
Tidskriftsartikel (refereegranskat)abstract
- Two relatives, a 61-year-old man and the 21-year-old grandson of his sister, suffered from bilateral visual loss and were diagnosed with Leber hereditary optic neuropathy. In both cases, the diagnosis was molecularly confirmed with the 11778 mitochondrial mutation. MRI showed increased T2 signal not only in the optic nerves and chiasm but also in the optic tracts, extending to the lateral geniculate bodies. To our knowledge, the latter finding has not been described previously.
|
|
| 7. |
|
|
