Characterization of white matter injury in a hypoxic-ischemic neonatal rat model by diffusion tensor MRI
| Autor: | Chung Nga Tam, Ed X. Wu, Pek-Lan Khong, Pik-To Cheung, Ho-Fai Lau, Silun Wang |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Pathology
medicine.medical_specialty External capsule Carotid Artery Common Models Neurological Ischemia Brain damage Nerve Fibers Myelinated Severity of Illness Index White matter Central nervous system disease Rats Sprague-Dawley medicine.artery medicine Animals Common carotid artery Stroke Ligation Advanced and Specialized Nursing Observer Variation business.industry medicine.disease Rats Disease Models Animal medicine.anatomical_structure Diffusion Magnetic Resonance Imaging Animals Newborn Hypoxia-Ischemia Brain Female Neurology (clinical) medicine.symptom Cardiology and Cardiovascular Medicine business Diffusion MRI |
| Zdroj: | Stroke. 39(8) |
| ISSN: | 1524-4628 |
| Popis: | Background and Purpose— We evaluate white matter (WM) injury after hypoxic-ischemic (HI) insult in a neonatal rat model using diffusion tensor imaging (DTI) to determine whether λ ∥ and λ ⊥ are able to characterize type and severity of brain damage. Methods— Eighteen 7-day-old Sprague-Dawley rats underwent unilateral ligation of left common carotid artery followed by 50 minutes (n=9) or 90 minutes (n=9) of hypoxia at 37°C. Rats were divided into 2 groups, according to absence (group A, n=11) or presence (group B, n=7) of cystic lesions on D7 post-HI T2-weighted imaging. DTI was performed for all rats at D1 and for group A rats at D7 post-HI. Signal intensity of ipsilateral and contralateral external capsule (EC) on D1 was compared by paired t test, with histological correlation. Results— Group A rats had significantly reduced FA, elevated trace, elevated λ ⊥, and similar λ ∥ on D1 in the ipsilateral compared to contralateral EC, whereas group B rats had significant reduction in all parameters in the ipsilateral EC. Elevated trace normalized on D7 in group A rats. Histopathologic results demonstrated reduced myelination in group A noncystic HI and severe necrosis in group B cystic HI. Conclusions— Increased λ ⊥ with no significant change in λ ∥ appears to characterize noncystic WM injury with reduced myelination, whereas reduction in both λ ∥ and λ ⊥ characterize severe damage with loss of structural integrity and necrosis. Combining with FA and trace, λ ∥ and λ ⊥ provide additional information which reflects type and severity of HI injury. |
| Databáze: | OpenAIRE |
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