Article

Diffusion tensor feature in vasogenic brain edema in cats. Brain Edema XIII

Bio-Organic and Natural Products Research Laboratory, McLean Hospital, Harvard Medical School, Boston, MA 02478, USA.
Acta neurochirurgica. Supplement 02/2006; 96:168-70. DOI: 10.1007/3-211-30714-1_37
Source: PubMed

ABSTRACT We investigated the correlation between the changes in diffusion tensor magnetic resonance imaging, regional water content, and tissue ultrastructure after vasogenic brain edema induced by cortical cold lesioning. In this cat model, E3 in the white matter was dominantly increased while fractional anisotropy (FA) was significantly decreased 8 hours after cortical cold lesioning. This finding indicates that water diffusion in the cortical white matter mainly increased perpendicularly rather than parallel to the direction of the nerve fibers. Additionally, in the area where edema is mild or moderate (tissues with water content of 65% to 75%), FA in the chronic phase was significantly lower than that in the acute phase. Histological examination demonstrated disordered arrangement of nerve fibers, highly dissociated neuronal fibers due to extracellular accumulation of protein rich-fluid, and enlarged interfiber spaces in the acute phase.

0 Followers
 · 
77 Views
 · 
0 Downloads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Wallerian degeneration in pyramidal tract following supratentorial stroke has been detected by some studies using diffusion tensor imaging (DTI), but the Wallerian degeneration in middle cerebellar peduncle after pontine infarction and its potential clinical significance remain to be confirmed. Seventeen patients with a recent focal pontine infarct underwent 3 DTIs at week 1 (W1), week 4 (W4), and week 12 (W12) after onset. Seventeen age-matched and gender-matched controls underwent DTI one time. Mean diffusivity and fractional anisotropy (FA) were measured in the basis pontis and bilateral middle cerebellar peduncles. Neurological deficit, motor deficit, functional independence, and limbs ataxia were assessed with the National Institutes of Health (NIH) Stroke Scale, Fugl-Meyer scale, Barthel Index, and the second part of International Cooperative Ataxia Rating Scale. FA values at the bilateral middle cerebellar peduncles decreased significantly from W1 to W12 progressively (P<.01). The patients improved on the NIH Stroke Scale, Fugl-Meyer scale, and Barthel Index over time (P<.01). Greater absolute value of percentage reduction of FA at the bilateral middle peduncles, however, was associated with the less absolute value of percentage reduction of the NIH Stroke Scale and less increase in the Fugl-Meyer scale, as well as greater ataxia over time. Wallerian degeneration in the middle cerebellar peduncle revealed by DTI may hinder the process of neurological recovery following a focal pontine infarct.
    Neurorehabilitation and neural repair 02/2009; 23(7):692-8. DOI:10.1177/1545968308331142 · 4.62 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The MRI manifestations of Hashimoto's Encephalopathy (HE) can vary from normal appearance, ischemic lesions, demyelination, vasogenic edema to atrophy. The diverse MRI features of HE reported in the literature made it difficult to understand the pathological process and monitoring the prognosis. To investigate the dynamic changes of MRI manifestations in HE, two cases of HE were retrospectively analyzed with a series of longitudinal MRI data, including T2 weighted image (T2WI), T1 weighted image (T1WI), fluid attenuated inversion recovery image (FLAIR), diffusion weighted image and diffusion tensor image(DTI). Although similar acute ischemic manifestations were observed at the onset of HE in both cases, at follow-up, we observed different evolutions of HE on MRI between the two cases. It might partially account for the diversity of MRI findings (for example, a certain stage of HE). Clinical and MRI findings at follow-up also indicated that early treatment contributed to the recovery of lesions.
    Journal of the neurological sciences 10/2010; 300(1-2):169-72. DOI:10.1016/j.jns.2010.09.019 · 2.26 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The histologic characteristics that are the basis for diagnosis of central nervous system conditions cannot be visualized directly using magnetic resonance (MR) methods, but clinical diagnosis may be based on the frequency and pattern of MR imaging signs, which represent predominantly the gross morphologic features of lesions. Additional quantitative MR measures of myelination, cell swelling, gliosis, and neuronal loss may also be used for more specific characterization of lesions. These measures include magnetization transfer ratio, apparent diffusion coefficient, and the concentrations or ratios of metabolites identified by spectroscopy. Confidence that an MR abnormality is responsible for the clinical signs depends primarily on the degree of correspondence between the site of the lesion and the neuroanatomical localization.
    Veterinary Radiology &amp Ultrasound 03/2011; 52(1 Suppl 1):S23-31. DOI:10.1111/j.1740-8261.2010.01782.x · 1.26 Impact Factor
Show more