Restriction spectrum imaging reveals decreased neurite density in patients with temporal lobe epilepsy
Autor: | Donald J. Hagler, Brianna M. Paul, Anders M. Dale, Richard Q. Loi, Carrie R. McDonald, Nathan S. White, Kelly M. Leyden, Vedang S. Uttarwar, Akshara R. Balachandra |
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Rok vydání: | 2016 |
Předmět: |
Male
Image Processing Restricted diffusion Nerve Fibers Myelinated Functional Laterality 030218 nuclear medicine & medical imaging Epilepsy Nerve Fibers Computer-Assisted 0302 clinical medicine Image Processing Computer-Assisted Medicine Cingulum (brain) Fornix Electroencephalography Anatomy Middle Aged Magnetic Resonance Imaging White Matter Temporal Lobe Diffusion Tensor Imaging Diffusion tensor imaging medicine.anatomical_structure Neurology Female Adult Clinical Sciences Uncinate fasciculus behavioral disciplines and activities Article Temporal lobe White matter Young Adult 03 medical and health sciences Fractional anisotropy Humans Crossing fibers Intracellular diffusion Neurology & Neurosurgery business.industry Neurosciences medicine.disease Epilepsy Temporal Lobe nervous system Case-Control Studies Myelinated Anisotropy Neurology (clinical) business Neuroscience 030217 neurology & neurosurgery Diffusion MRI |
Zdroj: | Epilepsia, vol 57, iss 11 Loi, RQ; Leyden, KM; Balachandra, A; Uttarwar, V; Jr, HDJ; Paul, BM; et al.(2016). Restriction spectrum imaging reveals decreased neurite density in patients with temporal lobe epilepsy. EPILEPSIA, 57(11), 1897-1906. doi: 10.1111/epi.13570. UC San Diego: Retrieved from: http://www.escholarship.org/uc/item/5989m562 |
ISSN: | 0013-9580 |
Popis: | Author(s): Loi, Richard Q; Leyden, Kelly M; Balachandra, Akshara; Uttarwar, Vedang; Hagler, Donald J; Paul, Brianna M; Dale, Anders M; White, Nathan S; McDonald, Carrie R | Abstract: ObjectiveDiffusion tensor imaging (DTI) has become a popular tool for delineating the location and extent of white matter injury in temporal lobe epilepsy (TLE). However, DTI yields nonspecific measures that are confounded by changes occurring within both the intracellular and extracellular environments. This study investigated whether an advanced diffusion method, restriction spectrum imaging (RSI) could provide a more robust measure of white matter injury in TLE relative to DTI due to RSI's ability to separate intraaxonal diffusion (i.e., neurite density; ND) from diffusion associated with extraaxonal factors (e.g., inflammation; crossing fibers).MethodsRSI and DTI scans were obtained on 21 patients with TLE and 11 age-matched controls. RSI-derived maps of ND, isotropic-hindered (IH) and isotropic-free (IF) water, and crossing fibers (CFs) were compared to DTI-derived fractional anisotropy (FA) maps. Voxelwise and tract-based analyses were performed comparing patients with TLE to controls on each diffusion metric.ResultsReductions in FA were seen primarily in frontotemporal white matter in TLE, and they were most pronounced proximal to the seizure focus. Reductions in ND corresponded to those seen in the FA maps; however, ND reductions were greater in magnitude, more lateralized to the epileptogenic hemisphere, and showed a broader pattern. Increases in IF/IH and effects from CFs also contributed to reduced FA in the ipsilateral parahippocampal cingulum and fornix, with decreases in IH extending into extratemporal regions. Reduced ND of the uncinate fasciculus was associated with longer disease duration, whereas FA was not associated with any clinical variables.SignificanceRSI may provide a more specific measure of white matter pathology in TLE, distinguishing regions primarily affected by axonal/myelin loss from those where CFs and increases in extracellular water also play a role. By providing a more specific measure of axonal/myelin loss, RSI-derived ND may better reflect overall white matter burden in epilepsy. |
Databáze: | OpenAIRE |
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