Quantitative measurement of cerebral oxygen extraction fraction using MRI in patients with MELAS

PLoS One. 2013 Nov 8;8(11):e79859. doi: 10.1371/journal.pone.0079859. eCollection 2013.


Objective: To quantify the cerebral OEF at different phases of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) by using MRI.

Methods: We recruited 32 patients with MELAS confirmed by gene analysis. Conventional MRI scanning, as well as functional MRI including arterial spin labeling and oxygen extraction fraction imaging, was undertaken to obtain the pathological and metabolic information of the brains at different stages of stroke-like episodes in patients. A total of 16 MRI examinations at the acute and subacute phase and 19 examinations at the interictal phase were performed. In addition, 24 healthy volunteers were recruited for control subjects. Six regions of interest were placed in the anterior, middle, and posterior parts of the bilateral hemispheres to measure the OEF of the brain or the lesions.

Results: OEF was reduced significantly in brains of patients at both the acute and subacute phase (0.266 ± 0.026) and at the interictal phase (0.295 ± 0.009), compared with normal controls (0.316 ± 0.025). In the brains at the acute and subacute phase of the episode, 13 ROIs were prescribed on the stroke-like lesions, which showed decreased OEF compared with the contralateral spared brain regions. Increased blood flow was revealed in the stroke-like lesions at the acute and subacute phase, which was confined to the lesions.

Conclusion: MRI can quantitatively show changes in OEF at different phases of stroke-like episodes. The utilization of oxygen in the brain seems to be reduced more severely after the onset of episodes in MELAS, especially for those brain tissues involved in the episodes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Case-Control Studies
  • Cerebrovascular Circulation / physiology
  • Cerebrum / blood supply
  • Cerebrum / metabolism
  • Child
  • Female
  • Humans
  • MELAS Syndrome / metabolism*
  • Magnetic Resonance Imaging / methods
  • Male
  • Oxygen / metabolism*
  • Young Adult


  • Oxygen

Grants and funding

This study was supported in part by the National Natural Science Foundation of China [No. 30870864 to Zhaoxia Wang and No. 81201154 to Xie Sheng]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.