Magnetic Resonance Imaging
Volume 28, Issue 4 , Pages 487-494, May 2010

Experimental hypoxic–ischemic encephalopathy: comparison of apparent diffusion coefficients and proton magnetic resonance spectroscopy

  • Yang-Kang Li

      Affiliations

    • Department of Radiology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong 515041, China
    • Corresponding Author InformationCorresponding author. Tel.: +86 0754 88555844; fax: +86 0754 88535687.
    • ,
  • Guo-Rui Liu

      Affiliations

    • Department of Medical Imaging, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, China
    • ,
  • Xiu-Guo Zhou

      Affiliations

    • Department of Radiology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong 515041, China
    • ,
  • Ai-Qun Cai

      Affiliations

    • Department of Radiology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong 515041, China

Received 21 January 2009; received in revised form 9 October 2009; accepted 6 December 2009. published online 14 January 2010.

Abstract 

This study aims to compare the apparent diffusion coefficients (ADCs) and proton magnetic resonance spectroscopy (1H-MRS) in the first 24 h of acute hypoxic-ischemic brain damage (HIBD) in piglets. Twenty-five 7-day-old piglets were subjected to transient bilateral common carotid artery occlusion followed by ventilation with 4% oxygen for 1 h. Diffusion-weighted imaging (DWI) and 1H-MRS were performed on cessation of the insult or at 3, 6, 12 or 24 h after resuscitation (all n=5). ADCs, N-acetylaspartate/choline (NAA/Cho), NAA/creatine (NAA/Cr), lactate/NAA (Lac/NAA), Lac/Cho and Lac/Cr were calculated. Cerebral injury was evaluated by pathological study and Hsp70 immunohistochemical analysis. On cessation of the insult, ADCs, NAA/Cho and NAA/Cr reduced, Lac/NAA, Lac/Cho and Lac/Cr increased. From 3 to 12 h after resuscitation, ADCs, Lac/NAA, Lac/Cho and Lac/Cr recovered, NAA/Cho and NAA/Cr reduced. Twenty-four hours after resuscitation, ADCs reduced once more, Lac/NAA, Lac/Cho and Lac/Cr increased again, whereas NAA/Cho and NAA/Cr decreased continuously. Pathological study revealed mild cerebral edema on cessation of the insult and more and more severe cerebral injury after resuscitation. No Hsp70-positive cells were detected on cessation of the insult. From 3 to 12 hours after resuscitation, Hsp70-positive cells gradually increased. Twenty-four hours after resuscitation, Hsp70-positive cells decreased. Throughout the experiment, changes in NAA/Cho and pathology had the best correlation (R=–0.729). In conclusion, NAA/Cho is the most precise ratio to reflect the pathological changes of early HIBD. Transient ADCs and Lac ratios recovery do not predict the reversal of histological damage of early HIBD. Reducing astrocytic swelling is of great clinical significance.

Keywords: Hypoxia-ischemia, Brain, Apparent diffusion coefficient, Magnetic resonance spectroscopy, Piglet, Newborn

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PII: S0730-725X(09)00294-X

doi:10.1016/j.mri.2009.12.002

Magnetic Resonance Imaging
Volume 28, Issue 4 , Pages 487-494, May 2010

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