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- Falk Delgado, Anna, et al.
(författare)
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Diffusion kurtosis imaging of gliomas grades II and III : a study of perilesional tumor infiltration, tumor grades and subtypes at clinical presentation
- 2017
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Ingår i: Radiology and Oncology. - : Walter de Gruyter GmbH. - 1318-2099 .- 1581-3207. ; 51:2, s. 121-129
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Tidskriftsartikel (refereegranskat)abstract
- Background. Diffusion kurtosis imaging (DKI) allows for assessment of diffusion influenced by microcellular structures. We analyzed DKI in suspected low-grade gliomas prior to histopathological diagnosis. The aim was to investigate if diffusion parameters in the perilesional normal-appearing white matter (NAWM) differed from contralesional white matter, and to investigate differences between glioma malignancy grades II and III and glioma subtypes (astrocytomas and oligodendrogliomas).Patients and methods. Forty-eight patients with suspected low-grade glioma were prospectively recruited to this institutional review board-approved study and investigated with preoperative DKI at 3T after written informed consent. Patients with histologically proven glioma grades II or III were further analyzed (n=35). Regions of interest (ROIs) were delineated on T2FLAIR images and co-registered to diffusion MRI parameter maps. Mean DKI data were compared between perilesional and contralesional NAWM (student's t-test for dependent samples, Wilcoxon matched pairs test). Histogram DKI data were compared between glioma types and glioma grades (multiple comparisons of mean ranks for all groups). The discriminating potential for DKI in assessing glioma type and grade was assessed with receiver operating characteristics (ROC) curves.Results. There were significant differences in all mean DKI variables between perilesional and contralesional NAWM (p=< 0.000), except for axial kurtosis (p=0.099). Forty-four histogram variables differed significantly between glioma grades II (n=23) and III (n=12) (p=0.003-0.048) and 10 variables differed significantly between ACs (n=18) and ODs (n=17) (p=0.011-0.050). ROC curves of the best discriminating variables had an area under the curve (AUC) of 0.657-0.815.Conclusions. Mean DKI variables in perilesional NAWM differ significantly from contralesional NAWM, suggesting altered microstructure by tumor infiltration not depicted on morphological MRI. Histogram analysis of DKI data identifies differences between glioma grades and subtypes.
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- Falk Delgado, Anna, et al.
(författare)
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Preoperative Quantitative MR Tractography Compared with Visual Tract Evaluation in Patients with Neuropathologically Confirmed Gliomas Grades II and III : A Prospective Cohort Study
- 2016
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Ingår i: Radiology research and practice. - : Hindawi Limited. - 2090-1941 .- 2090-195X. ; 2016:1, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose. Low-grade gliomas show infiltrative growth in white matter tracts. Diffusion tensor tractography can noninvasively assess white matter tracts. The aim was to preoperatively assess tumor growth in white matter tracts using quantitative MR tractography (3T). The hypothesis was that suspected infiltrated tracts would have altered diffusional properties in infiltrated tract segments compared to noninfiltrated tracts. Materials and Methods. Forty-eight patients with suspected low-grade glioma were included after written informed consent and underwent preoperative diffusion tensor imaging in this prospective review-board approved study. Major white matter tracts in both hemispheres were tracked, segmented, and visually assessed for tumor involvement in thirty-four patients with gliomas grade II or III (astrocytomas or oligodendrogliomas) on postoperative neuropathological evaluation. Relative fractional anisotropy (rFA) and mean diffusivity (rMD) in tract segments were calculated and compared with visual evaluation and neuropathological diagnosis. Results. Tract segment infiltration on visual evaluation was associated with a lower rFA and high rMD in a majority of evaluated tract segments (89% and 78%, resp.). Grade II and grade III gliomas had similar infiltrating behavior. Conclusion. Quantitative MR tractography corresponds to visual evaluation of suspected tract infiltration. It may be useful for an objective preoperative evaluation of tract segment involvement.
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- Larsson, Elna-Marie, et al.
(författare)
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MRI with diffusion tensor imaging post-mortem at 3.0 T in a patient with frontotemporal dementia.
- 2004
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Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 17:4, s. 316-319
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Tidskriftsartikel (refereegranskat)abstract
- The formalin-fixed brain of a patient with clinically diagnosed frontotemporal dementia (FTD) was examined post-mortem using magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI) at 3.0 T. Frontotemporal atrophy as well as bilateral frontal white matter abnormalities were seen. The white matter changes were slightly more extensive on DTI than on conventional MRI. Correlation with histopathology of the corresponding regions revealed typical frontal lobe degeneration of non-Alzheimer type, with mild frontotemporal degeneration in the outer cortical layers and a moderate frontal white matter gliosis with demyelination. Post-mortem MRI/DTI with histopathologic correlation will enhance our understanding of the basis of white matter changes observed in dementia patients and may improve the in vivo MRI/DTI diagnostic assessment in FTD.
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- Lätt, Jimmy, et al.
(författare)
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In vivo visualization of displacement-distribution-derived parameters in q-space imaging.
- 2008
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Ingår i: Magnetic Resonance Imaging. - : Elsevier BV. - 1873-5894 .- 0730-725X. ; 26:1, s. 77-87
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Tidskriftsartikel (refereegranskat)abstract
- Objective This study aimed to explore the potential of in vivo q-space imaging in the differentiation between different cerebral water components. Materials and Methods Diffusion-weighted imaging was performed in six directions with 32 equally spaced q values and a maximum b value of 6600 s/mm2. The shape of the signal-attenuation curve and the displacement propagator were examined and compared with a normal distribution using the kurtosis parameter. Maps displaying kurtosis, fast and slow components of the apparent diffusion coefficients, fractional anisotropy and directional diffusion were calculated. The displacement propagator was further described by the full width at half and at tenth maximum and by the probability density of zero displacement P(0). Three healthy volunteers and three patients with previously diagnosed multiple sclerosis (MS) were examined. Results Simulations indicated that the kurtosis of a signal-attenuation curve can determine if more than one water component is present and that care must be taken to select an appropriate threshold. It was possible to distinguish MS plaques in both signal and diffusional kurtosis maps, and in one patient, plaques of different degree of demyelinization showed different behavior. Discussion Our results indicate that in vivo q-space analysis is a potential tool for the assessment of different cerebral water components, and it might extend the diagnostic interpretation of data from diffusion magnetic resonance imaging.
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- Mårtensson, Johanna
(författare)
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Diffusion tensor magnetic resonance imaging of the brain : Tractography analysis with application in healthy individuals and patients
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In study 1, thirty-eight healthy controls were used for optimization of the method. Fifteen patients with progressive supranuclear palsy and an equal number of age-matched healthy controls underwent diffusion tensor MRI and were then investigated and compared groupwise.It was shown that tractography analyses may preferably be performed regionally, such as along the tracts or in different segments of the tracts. Normalization of white matter tracts can be performed using anatomical landmarks.In study 2, 104 males and 153 females in the age interval 13 to 84 years of age participated as healthy individuals in order to investigate age-related changes with diffusion tensor MRI.It was shown that spatially differences in age-related changes exist between subdivided segments within white matter tracts. The aging processes within the CB and the IFO vary regionally.In study 3, 38 human brains were used for investigation of the white matter tract inferior longitudinal fasciculus (ILF) and its subcomponents. Of these, white matter anatomical dissection was performed in 14 post-mortem normal human brains. The remaining 24 brains were investigated in vivo with diffusion tensor MRI in healthy individuals.It was validated that fibers of the ILF in the occipito-temporal region have a clear, constant and detailed organisation. The anatomical connectivity pattern, and quantitative differences between the ILF subcomponents, confirmed a pivotal role of the ILF.In study 4, 12 patients with iNPH were included in the study and examined with diffusion tensor at three time points. For comparison, 12 healthy controls, matched by gender and age were also included. Controls were examined with MRI only once.It was shown that DTI measures differ significantly between patients with iNPH and healthy controls. DTI measures of the CC, the CST and the SLF, correlated to changes in clinical symptoms after shunt surgery.Deeper knowledge about functions of the brain increases possibilities to take advantages from DTI analyses with tractography.
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