Assessment Of White Matter Injury Research Articles

Presurgical simulation for neuroendoscopic procedures: Virtual study of the integrity of neurological pathways using diffusion tensor imaging tractography.

Background:White matter (WM) transgression is an unexplored concept in neuroendoscopy. Diffusion tensor image (DTI) tractography could be implemented as a planning and postoperative evaluation tool in functional disconnection procedures (FDPs), which are, currently, the subject of technological innovations. We intend to prove the usefulness of this planning method focused on the assessment of WM injury that is suitable for planning FDPs.Methods:Ten cranial magnetic resonance studies (20 sides) without pathological findings were processed. Fascicles were defined by two regions of interest (ROIs) using the fiber assignment method by the continuous tracking approach. Using three-dimensional (3D) simulation and DTI tractography, we created an 8-mm virtual endoscope and an uninjured inferior fronto-occipital fasciculus (IFOF) from two ROIs. The injured tract was generated using a third ROI built from the 3D model of the intersection of the oriented trajectory of the endoscope with the fascicle. Data and images were quantitatively and qualitatively analyzed.Results:The average percentage of the injured fibers was 32.0% (range: 12.4%–70%). The average intersected volume was 1.1 cm3 (range: 0.3–2.3 cm3). Qualitative analysis showed the inferior medial quadrant of the inferior fronto-occipital fasciculus (IFOF) as the most frequently injured region. No hemispherical asymmetry was found (P > 0.5).Conclusion:DTI tractography is a useful surgical planning tool that could be implemented in several endoscopic procedures. Together with a functional atlas, the presented technique provides a noninvasive method to assess the potential sequelae and thus to optimize the surgical route. The suggested method could be implemented to analyze pathological WM fascicles and to assess the surgical results of FDP such as hemispherotomy or amygdalohippocampectomy. More studies are needed to overcome the limitations of the tractography based information and to develop more anatomically and functionally reliable planning systems.

Assessment of white matter injury in systemic lupus erythematosus with cognitive dysfunction by diffusion tensor imaging

Objective To investigate the white matter injury in patients with systemic lupus erythematosus (SLE) combined with cognitive dysfunction by diffusion tensor imaging (DTI). Methods The Montreal cognitive assessment, conventional magnetic resonance imaging (MRI) and DTI were performed in 11 SLE patients with cognitive dysfunction (CDF), 11 SLE patients without cognitive dysfunction (non-CDF) and 10 health controls. Local gray differences among three groups were compared by SPM5 software and voxel-based analysis. Results In conventional MRI, abnormal lesions were detected in 3 CDF patients. In DTI, compared to non-CDF group, CDF patients showed significantly increased apparent diffusion coefficient (ADC) values in right precuneus and brodmann area 6, 21 (P<0.01). No difference of fractional anisotropy (FA) was found between these two groups. Compared to health controls, CDF patients showed significantly decreased FA values in right parahippocampa gyrus, cerebellar tonsil and pons (P<0.01), and increased ADC values in right superior frontal gyrus, cuneus, middle temporal gyrus, insula, brodmann area (13, 20, 21, 27, 30, 47), and left middle frontal gyrus, brodmann area 10, cingulate gyrus and corpus callosum (P<0.01). Compared to health controls, non-CDF patients showed significantly increased ADC values in right parahippocampa gyrus, superior frontal gyrus, brodmann area (10, 25), left middle temporal gyrus, middle occipital gyrus, brodmann area (3, 13, 19, 25), bilateral insula and corpus callosum (P<0.01), and no difference of FA. Conclusions DTI is more sensitive to detect white matter impairment of cognitive dysfunction in SLE patients than conventional MRI. Key words: Diffusion magnetic resonance imaging; Lupus erythematosus, systemic/CO/RA; Cognition disorders/CO/RA

Quantitative assessment of white matter injury in preterm neonates: Association with outcomes.

To quantitatively assess white matter injury (WMI) volume and location in very preterm neonates, and to examine the association of lesion volume and location with 18-month neurodevelopmental outcomes. Volume and location of WMI was quantified on MRI in 216 neonates (median gestational age 27.9 weeks) who had motor, cognitive, and language assessments at 18 months corrected age (CA). Neonates were scanned at 32.1 postmenstrual weeks (median) and 68 (31.5%) had WMI; of 66 survivors, 58 (87.9%) had MRI and 18-month outcomes. WMI was manually segmented and transformed into a common image space, accounting for intersubject anatomical variability. Probability maps describing the likelihood of a lesion predicting adverse 18-month outcomes were developed. WMI occurs in a characteristic topology, with most lesions occurring in the periventricular central region, followed by posterior and frontal regions. Irrespective of lesion location, greater WMI volumes predicted poor motor outcomes (p = 0.001). Lobar regional analysis revealed that greater WMI volumes in frontal, parietal, and temporal lobes have adverse motor outcomes (all, p < 0.05), but only frontal WMI volumes predicted adverse cognitive outcomes (p = 0.002). To account for lesion location and volume, voxel-wise odds ratio (OR) maps demonstrate that frontal lobe lesions predict adverse cognitive and language development, with maximum odds ratios (ORs) of 78.9 and 17.5, respectively, while adverse motor outcomes are predicted by widespread injury, with maximum OR of 63.8. The predictive value of frontal lobe WMI volume highlights the importance of lesion location when considering the neurodevelopmental significance of WMI. Frontal lobe lesions are of particular concern.

Spatiotemporal changes in diffusion, T2 and susceptibility of white matter following mild traumatic brain injury.

Impaired white matter integrity in traumatic brain injury (TBI) can lead to deficits in various neurological functions. The differentiation of the underlying pathological processes, e.g. edema, demyelination, axonal damage, to name a few, is of key clinical interest for the assessment of white matter injury. In this study, a combination of T2 , diffusion and susceptibility MRI was used to study the spatiotemporal changes in white matter at 1 h, 3 h, and 1, 2, 7 and 14 days following TBI, using a rat controlled cortical impact (CCI) model. Based on radial diffusivity (RD), the rats were divided into two groups: group 1 showed widespread increases in RD along the corpus callosum of the ipsilesional hemisphere at day 2, and group 2 showed normal RD. Based on this group separation, group 1 also showed similar widespread changes in fractional anisotropy (FA) and T2 at day 2, and group 2 showed normal FA and T2 . The widespread changes in RD and T2 in group 1 on day 2 were apparently dominated by edema, which obscured possible myelin and axonal damage. In contrast, the susceptibility of group 1 showed more localized increases near the impact site on day 2, and otherwise similar contrast to the contralesional hemisphere. The localized susceptibility increase is probably a result of demyelination and axonal injury. The extent of brain damage between the two groups revealed by MRI was consistent with behavioral results, with the first group showing significantly increased forelimb asymmetry and increased forelimb foot fault deficits. Our results suggest that the combination of T2 , diffusion and susceptibility MRI may provide an opportunity for the differential assessment of edema and axonal damage in TBI. Copyright © 2016 John Wiley & Sons, Ltd.

Assessment of White Matter Injury and Outcome in Severe Brain Trauma. A Prospective Multicenter Cohort

Galanaud, Damien*; Perlbarg, Vincent†; Gupta, Rajiv‡; Stevens, Robert D.§; Sanchez, Paola∥; Tollard, Eléonore¶; De Champfleur, Nicolas Menjot**; Dinkel, Julien†; Faivre, Sébastien††; Stot-Ares, Gustavo‡‡; Veber, Benoit§§; Cottenceau, Vincent∥∥; Masson, François¶¶; Tourdias, Thomas∥∥; André, Edith***; Audibert, Gérard†††; Schmitt, Emmanuelle‡‡‡; Ibarrola, Danielle§§§; Dailler, Frédéric∥∥∥; Vanhaudenhuyse, Audrey¶¶¶; Tshibanda, Luaba****; Payen, Jean-François††††; Le Bas, Jean-François‡‡‡‡; Krainik, Alexandre‡‡‡‡; Bruder, Nicolas§§§§; Girard, Nadine∥∥∥∥; Laureys, Steven¶¶¶; Benali, Habib‡; Puybasset, Louis¶¶¶¶ for the Neuro Imaging for Coma Emergence and Recovery Consortium Author Information

Assessment of White Matter Injury and Outcome in Severe Brain Trauma

Existing methods to predict recovery after severe traumatic brain injury lack accuracy. The aim of this study is to determine the prognostic value of quantitative diffusion tensor imaging (DTI). In a multicenter study, the authors prospectively enrolled 105 patients who remained comatose at least 7 days after traumatic brain injury. Patients underwent brain magnetic resonance imaging, including DTI in 20 preselected white matter tracts. Patients were evaluated at 1 yr with a modified Glasgow Outcome Scale. A composite DTI score was constructed for outcome prognostication on this training database and then validated on an independent database (n=38). DTI score was compared with the International Mission for Prognosis and Analysis of Clinical Trials Score. Using the DTI score for prediction of unfavorable outcome on the training database, the area under the receiver operating characteristic curve was 0.84 (95% CI: 0.75-0.91). The DTI score had a sensitivity of 64% and a specificity of 95% for the prediction of unfavorable outcome. On the validation-independent database, the area under the receiver operating characteristic curve was 0.80 (95% CI: 0.54-0.94). On the training database, reclassification methods showed significant improvement of classification accuracy (P < 0.05) compared with the International Mission for Prognosis and Analysis of Clinical Trials score. Similar results were observed on the validation database. White matter assessment with quantitative DTI increases the accuracy of long-term outcome prediction compared with the available clinical/radiographic prognostic score.

Radiological assessment of white matter injury in very preterm infants

Despite improvements in neonatal care, infants born very prematurely who survive the neonatal period are still at risk of neurodevelopmental disabilities. One of the main determinants for a poorer outcome seems to be damage to the cerebral white matter, which frequently occurs during the perinatal period. This article summarizes the radiological assessment of white matter injury in very preterm infants, striving to aid clinicians who provide parents and care takers with prognostic information on the development of their preterm born infants. As the expertise of radiologists in assessing neonatal brain MRI may vary widely amongst centers, we also strive to provide radiologists with information on imaging findings of white matter injury.

Fractional anisotropy for assessment of white matter tracts injury in methylmalonic acidemia.

Methylmalonic acidemia (MMA) is a multifactorial autosomal recessive inborn error of organic acid metabolism, often presenting with neurological symptoms. As neurological disorders are often related to white matter injury, diffusion tensor imaging (DTI) is an excellent tool for assessment of white matter injury and possibly for diagnosing this disorder. We retrospectively analyzed DTI images of 12 patients with MMA (7 males, 5 females, age range: 7 - 12 months, mean age: 9.25 +/- 1.70 months) with negative MRI findings. And another 12 age-matched and gender-matched infants were enrolled as control subjects. Fractional anisotropy (FA) of different white matter tracts of the brain was measured in both groups. For patients with negative MRI findings, compared with healthy infants, a statistically significant reduction in DTI FA value of the frontal white matter, temporal white matter, and occipital white matter was observed (P < 0.01). In addition to conventional T1W and T2W MR Image, Brain DTI presents a useful, sensitive and complementary tool for the assessment of brain damage in patients with MMA.

Long Term Assessment of White Matter Injury After Spinal Cord Ischemia in Rabbits

s: 33rd Annual Meeting of the Society of Neurosurgical Anesthesia and Critical Care: DRUGS AND TECHNIQUES

Assessment of white matter injury following prolonged focal cerebral ischaemia in the rat.

The ability of putative neuroprotective compounds to protect against white matter injury remains poorly investigated due to the lack of suitable methods for assessing white matter injury. This study was therefore designed to investigate the utility of Tau 1 (oligodendrocytes/axons), myelin basic protein (MBP; myelin) and amyloid precursor protein (APP; axons) immunohistochemistry in assessing white matter injury at various times following middle cerebral artery occlusion (MCAO) in the rat. Focal cerebral, ischaemia was induced in halothane-anaesthetised rats using an intraluminal thread model. At 24 h, 1 and 2 weeks following MCAO, white matter injury was assessed using Tau 1, APP, MBP and Luxol-fast blue staining and neuronal injury with cresyl fast violet (CFV). In histologically normal tissue MBP immunoreactivity was detected in myelinated fibre tracts, while Tau 1 and APP were axonally located. At 24 h following permanent MCAO, MBP, and Tau 1 staining remained relatively unchanged within the myelin and axonal compartments of the ischaemic region. In contrast, increased Tau 1 staining was apparent in oligodendrocytes within ischaemic tissue, while APP accumulated in axons surrounding the lesion. At 1 and 2 weeks following transient MCAO, Tau 1 and APP staining was markedly decreased within ischaemic tissue. Marked reduction in MBP levels within ischaemic tissue were not detected until 2 weeks following MCAO. The area of axonal injury as assessed by reduced Tau 1 or APP staining correlated with the area of neuronal damage as assessed by CFV staining. This study shows that MBP, Tau 1 and APP immunohistochemistry can be utilised to assess myelin and axonal integrity following sustained ischaemia using standard image analysis techniques.

Topographical and quantitative assessment of white matter injury following a focal ischaemic lesion in the rat brain

Axonal injury following cerebral ischaemia has attracted less attention than damage in grey matter. However, it is becoming increasingly recognised that axons are highly vulnerable to focal ischaemia [D. Dewar, D.A. Dawson, Changes of cytoskeletal protein immunostaining in myelinated fibre tracts after focal cerebral ischaemia in the rat, Acta. Neuropathol., 93 (1997) 71–77] [2]; [L. Pantoni, J.H. Garcia, J.A. Gutierrez, Cerebral white matter is highly vulnerable to ischemia, Stroke, 27 (1996) 1641–1647] [10]; [P.S. Yam, T. Takasago, D. Dewar, D.I. Graham, J. McCulloch, Amyloid precursor protein accumulates in white matter at the margin of a focal ischaemic lesion, Brain Res., 760 (1997) 150–157] [15]. Since white matter does not contain neuronal cell bodies or synapses it is likely that the mechanisms of injury and strategies for its protection are different from those in grey matter. In order that the effect of therapeutic intervention on the protection of axons can be assessed, a method by which axonal injury can be mapped and quantified is required. For this purpose, we investigated immunocytochemical methods using amyloid precursor protein (APP) following permanent middle cerebral artery occlusion in the rat. APP is transported by fast anterograde axonal transport [E.H. Koo, S.S. Sisodia, D.R. Archer, L.J. Martin, A. Weidemann, K. Beyreuther, P. Fischer, C.L. Masters, D.L. Price, Precursor of amyloid protein in Alzheimer disease undergoes fast anterograde axonal transport, Proc. Natl. Acad. Sci. U.S.A. 87 (1990) 1561–1565] [7]and has been shown to accumulate following a variety of insults to axons, indicative of dysfunction of axonal transport [R.N. Kalaria, S.U. Bhatti, E.A. Palatinsky, D.H. Pennington, E.R. Shelton, H.W. Chan, G. Perry, W.D. Lust, Accumulation of the beta amyloid precursor protein at sites of ischemic injury in rat brain, Neuroreport, 4 (1993) 211–214] [4]; [T. Kawarabayashi, M. Shoji, Y. Harigaya, H. Yamaguchi, S. Hirai, Expression of APP in the early stage of brain damage, Brain Res., 563 (1991) 334–338] [5]; [N. Otsuka, M. Tomonaga, K. Ikeda, Rapid appearance of beta-amyloid precursor protein immunoreactivity in damaged axons and reactive glial cells in rat brain following needle stab injury, Brain Res., 568 (1991) 335–338] [9]; [K. Shigematsu, P.L. McGeer, Accumulation of amyloid precursor protein in neurons after intraventricular injection of colchicine, Am. J. Pathol., 140 (1992) 787–794] [12]. We have been able to map the topographical relationship between APP accumulation and region of infarction using immunocytochemistry and image analysis techniques. Additionally, using a semi-quantitative scoring system, we have demonstrated that there is a relationship between the amount of APP accumulation and the volume of infarction following middle cerebral artery occlusion. These methods will be useful in the future for the assessment of therapeutic interventions on the protection of axons following ischaemic injury. Themes: Disorders of the nervous system Topics: Ischemia