Diffusion Tensor Imaging and Colored Fractional Anisotropy Mapping of the Ventralis Intermedius Nucleus of the Thalamus

Neurosurgery ◽  
2011 ◽  
Vol 69 (5) ◽  
pp. 1124-1130 ◽  
Author(s):  
Mark Sedrak ◽  
Alessandra Gorgulho ◽  
Andrew Frew ◽  
Eric Behnke ◽  
Antonio DeSalles ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Fractional Anisotropy ◽  
Diffusion Tensor ◽  
Patient Specific ◽  
Superior Cerebellar Peduncle ◽  
Resonance Imaging ◽  
Neurosurgical Planning

Abstract BACKGROUND The ventralis intermedius (VIM) nucleus of the thalamus is the primary surgical target for treatment of tremor. Most centers rely on indirect targeting based on atlas-defined coordinates rather than patient-specific anatomy, making intraoperative physiological mapping critical. Detailed identification of this target based on patient-specific anatomic features can help optimize the surgical treatment of tremor. OBJECTIVE To study colored fractional anisotropic images and diffusion tensor imaging (DTI) tractography to identify characteristic magnetic resonance appearances of the VIM nucleus. METHODS Four patients undergoing stereotactic surgery for essential tremor (ET) were retrospectively studied with analysis of magnetic resonance imaging-based colored fractional anisotropy (FA) images and fiber tractography. All were scanned with a 1.5-T magnetic resonance imaging unit, and all sequences were obtained before frame placement. Because the goal of this study was to identify the DTI characteristics of physiologically defined VIM nucleus, we selected and studied patients who had undergone DTI and had efficacious tremor control with intraoperative microlesioning effect and tremor reduction with less than 2.0-V stimulation. RESULTS Analysis of color FA maps, which graphically illustrate fiber directionality, revealed consistent anatomic patterns. The region of the VIM nucleus can be seen as an intermediate region where there is a characteristic transition of color. Presumptive VIM nucleus interconnectivity with sensorimotor cortex and cerebellum was identified via the internal capsule and the superior cerebellar peduncle, respectively. FA maps could also be used to distinguish segments of gray matter, white matter, and gray-white matter boundaries. CONCLUSION Analysis of DTI and FA maps on widely available 1.5-T magnetic resonance imaging yields clear identification of various structures key to neurosurgical targeting. Prospective evaluation of integrating DTI into neurosurgical planning may be warranted.

Fractional Anisotropy Levels Derived From Diffusion Tensor Imaging in Cervical Syringomyelia

Neurosurgery ◽  
2010 ◽  
Vol 67 (4) ◽  
pp. 901-905 ◽  
Author(s):  
Florian Roser ◽  
Florian Ebner ◽  
Gottlieb Maier ◽  
Marcos Tatagiba ◽  
Thomas Nägele ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Evoked Potentials ◽  
Fractional Anisotropy ◽  
Diffusion Tensor ◽  
Motor Evoked Potentials ◽  
Neurological Deficits ◽  
Resonance Imaging

Abstract BACKGROUND: Syringomyelia can result in major functional disability. Conventional imaging techniques frequently fail to detect the underlying cause of syringomyelia. The prediction as to whether syringomyelia might lead to neurological deficits is still challenging. OBJECTIVE: We hypothesized that fractional anisotropy (FA) derived from diffusion tensor imaging (DTI) is a parameter to detect dynamic forms of syringomyelia. METHODS: Six patients with cervical syringomyelia, all comparable in size, shape, and location, were examined, along with 2 volunteers. Patients underwent electrophysiological recordings (somatosensory evoked potentials, motor evoked potentials, silent periods). Magnetic resonance imaging (1.5 T) was performed with a 6-element spine coil. Anatomic images were acquired with a 3-dimensional, constructive interference in steady-state sequence, and DTI with an echo-planar imaging sequence (5-mm thickness, b value 800 s/mm2) using the generalized autocalibrating partially parallel acquisitions technique. The positions were centered on the syrinx in the volunteers between the C2 and Th1. DTI data were interpolated to a spatial resolution of 0.5 mm. After calculation of a diffusion tensor in each pixel, an FA map was calculated and profiles of the FA values across the spinal cord were calculated in all slices. RESULTS: FA values were lower at the level of all examined syrinxes and reached normal values beyond them. Electrophysiological results correlated with the decrease in FA value. There were no presyrinx changes in the white matter tracts in terms of signs of FA changes beneath the syrinx. CONCLUSION: DTI of syringomyelia can demonstrate white matter fiber tracts around and beyond the syrinx consistent with electrophysiological values. DTI of the cervical spine can provide quantitative information about the pathological characteristics beyond the abnormalities visible on magnetic resonance imaging.

scholarly journals Structural disconnectivity in schizophrenia: a diffusion tensor magnetic resonance imaging study

2003 ◽  
Vol 182 (5) ◽  
pp. 439-443 ◽  
Author(s):  
J. Burns ◽  
D. Job ◽  
M. E. Bastin ◽  
H. Whalley ◽  
T. Macgillivray ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Fractional Anisotropy ◽  
Structural Integrity ◽  
Diffusion Tensor ◽  
Uncinate Fasciculus ◽  
Arcuate Fasciculus ◽  
Resonance Imaging ◽  
White Matter Tracts

BackgroundThere is growing evidence that schizophrenia is a disorder of cortical connectivity Specifically, frontotemporal and frontoparietal connections are thought to be functionally impaired. Diffusion tensor magnetic resonance imaging (DT–MRI) is a technique that has the potential to demonstrate structural disconnectivity in schizophrenia.AimsTo investigate the structural integrity of frontotemporal and frontoparietal white matter tracts in schizophrenia.MethodThirty patients with DSM–IV schizophrenia and thirty matched control subjects underwent DT–MRI and structural MRI. Fractional anisotropy – an index of the integrity of white matter tracts – was determined in the uncinate fasciculus, the anterior cingulum and the arcuate fasciculus and analysed using voxel-based morphometry.ResultsThere was reduced fractional anisotropy in the left uncinate fasciculus and left arcuate fasciculus in patients with schizophrenia compared with controls.ConclusionsThe findings of reduced white matter tract integrity in the left uncinate fasciculus and left arcuate fasciculus suggest that there is frontotemporal and frontoparietal structural disconnectivity in schizophrenia.

White matter differences in euthymic bipolar I disorder: a combined magnetic resonance imaging and diffusion tensor imaging voxel-based study

2013 ◽  
Vol 15 (4) ◽  
pp. 365-376 ◽  
Author(s):  
Louise Emsell ◽  
Camilla Langan ◽  
Wim Van Hecke ◽  
Gareth J Barker ◽  
Alexander Leemans ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Resonance Imaging ◽  
Bipolar I Disorder ◽  
And Diffusion

scholarly journals Assessment of lumbar disc herniaton using fractional anisotropy in diffusion tensor imaging along with conventional T2-weighted imaging

2019 ◽  
Vol 33 (1) ◽  
pp. 24-31
Author(s):  
Marco Perri ◽  
Marialuisa D’Elia ◽  
Giulia Castorani ◽  
Rosario Francesco Balzano ◽  
Annamaria Pennelli ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Diffusion Tensor Imaging ◽  
Magnetic Resonance ◽  
Fractional Anisotropy ◽  
Lumbar Disc Herniation ◽  
Diffusion Tensor ◽  
Lumbar Disc ◽  
Study Group ◽  
Conventional Magnetic Resonance Imaging ◽  
Resonance Imaging

Objective To assess the usefulness of diffusion tensor imaging and its fractional anisotropy map along with conventional T2-weighted imaging in evaluating the anisotropic water diffusion variations of annulus fibres involved in herniation disc pathology. Materials and methods Seventy-five patients with previous medical ethics committee approval and informed consent experiencing low back pain were selected for this prospective randomised blinded trial. Lumbar disc fractional anisotropy maps were obtained acquiring diffusion tensor sequences on a 3T machine. The matrix of nucleus pulposus and structures of annulus fibres were analysed using fractional anisotropy textural features to highlight any presence of lumbar disc herniation. Observer variability and reliability between two neuroradiologists were evaluated. The χ2 test, two-tailed t test and linear regression analysis were used to focus differences in patients’ demographic data and magnetic resonance imaging findings. Results Annular fissures with extrusions were identified using diffusion tensor imaging in 10 out of 17 discs (study group) previously assessed as bulging discs using conventional magnetic resonance imaging. Eighteen extrusions out of 39 (study group) disc levels were identified on diffusion tensor imaging compared to eight extrusions highlighted on T2-weighted imaging ( P < 0.01). All eight (study group) disc extrusions evaluated on T2-weighted imaging showed annular fissures on diffusion tensor imaging. Seven out of 14 (study group) protrusions highlighted on T2-weighted imaging had no annular fissures on diffusion tensor imaging; thirty-six disc levels in the control group had no evidence of annular fissures on diffusion tensor imaging ( P > 0.01). Conclusions The addition of diffusion tensor imaging sequences and fractional anisotropy mapping to a conventional magnetic resonance imaging protocol could be useful in detecting annular fissures and lumbar disc herniation.

Diffusion tensor imaging abnormalities in depressed multiple sclerosis patients

2009 ◽  
Vol 16 (2) ◽  
pp. 189-196 ◽  
Author(s):  
A. Feinstein ◽  
P. O'Connor ◽  
N. Akbar ◽  
L. Moradzadeh ◽  
CJM Scott ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Multiple Sclerosis ◽  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Grey Matter ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Resonance Imaging ◽  
Normal Appearing White Matter

Depression is common in patients with multiple sclerosis, but to date no studies have explored diffusion tensor imaging indices associated with mood change. This study aimed to determine cerebral correlates of depression in multiple sclerosis patients using diffusion tensor imaging. Sixty-two subjects with multiple sclerosis were assessed for depression with the Beck Depression Inventory (BDI-II). All subjects underwent magnetic resonance imaging. Whole brain and regional volumes were calculated for lesions (hyper/hypointense) and normal-appearing white and grey matter. Fractional anisotropy and mean diffusivity were calculated for each brain region. Magnetic resonance imaging comparisons were undertaken between depressed (Beck Depression Inventory ≥19) and non-depressed subjects. Depressed subjects (n = 30) had a higher hypointense lesion volume in the right medial inferior frontal region, a smaller normal-appearing white matter volume in the left superior frontal region, and lower fractional anisotropy and higher mean diffusivity in the left anterior temporal normal-appearing white matter and normal-appearing grey matter regions, respectively. Depressed subjects also had higher mean diffusivity in right inferior frontal hyperintense lesions. Magnetic resonance imaging variables contributed to 43% of the depression variance. We conclude that the presence of more marked diffusion tensor imaging abnormalities in the normal-appearing white matter and normal-appearing grey matter of depressed subjects highlights the importance of more subtle measures of structural brain change in the pathogenesis of depression.

Advanced magnetic resonance imaging of neuromyelitis optica: a multiparametric approach

2011 ◽  
Vol 18 (6) ◽  
pp. 817-824 ◽  
Author(s):  
A Pichiecchio ◽  
E Tavazzi ◽  
G Poloni ◽  
M Ponzio ◽  
F Palesi ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Grey Matter ◽  
Diffusion Tensor ◽  
Healthy Controls ◽  
Voxel Based Morphometry ◽  
Resonance Imaging ◽  
Normal Appearing White Matter

Background: Several authors have used advanced magnetic resonance imaging (MRI) techniques to investigate whether patients with neuromyelitis optica (NMO) have occult damage in normal-appearing brain tissue, similarly to multiple sclerosis (MS). To date, the literature contains no data derived from the combined use of several advanced MRI techniques in the same NMO subjects. Objective: We set out to determine whether occult damage could be detected in the normal-appearing brain tissue of a small group of patients with NMO using a multiparametric MRI approach. Methods: Eight female patients affected by NMO (age range 44–58 years) and seven sex- and age-matched healthy controls were included. The techniques used on a 1.5 T MRI imaging scanner were magnetization transfer imaging, diffusion tensor imaging, tract-based spatial statistics, spectroscopy and voxel-based morphometry in order to analyse normal-appearing white matter and normal-appearing grey matter. Results: Structural and metabolic parameters showed no abnormalities in normal-appearing white matter of patients with NMO. Conversely, tract-based spatial statistics demonstrated a selective alteration of the optic pathways and the lateral geniculate nuclei. Diffusion tensor imaging values in the normal-appearing grey matter were found to be significantly different in the patients with NMO versus the healthy controls. Moreover, voxel-based morphometry analysis demonstrated a significant density and volume reduction of the sensorimotor cortex and the visual cortex. Conclusions: Our data disclosed occult structural damage in the brain of patients with NMO, predominantly involving regions connected with motor and visual systems. This damage seems to be the direct consequence of transsynaptic degeneration triggered by lesions of the optic nerve and spine.

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