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. 2013 May 13;8(5):e63013.
doi: 10.1371/journal.pone.0063013. Print 2013.

In vivo measurement of oxygenation changes after stroke using susceptibility weighted imaging filtered phase data

Meng Li  1 , Jiani Hu, Yanwei Miao, Huicong Shen, Dingbo Tao, Zhihong Yang, Qinghang Li, Stephanie Y Xuan, Waqar Raza, Sadeer Alzubaidi, E Mark Haacke
Affiliations

In vivo measurement of oxygenation changes after stroke using susceptibility weighted imaging filtered phase data

Meng Li et al. PLoS One. .

Abstract

Background and purpose: Cerebral blood oxygenation level is critical for following the evolution of stroke patients. The purpose of this study was to investigate the feasibility of measuring changes in blood oxygen levels for patients with acute stroke using SWI and to compare these changes with the patient's recovery over time.

Materials and methods: A total 30 MRI scans was performed on 10 acute ischemic stroke patients. Every patient was followed at three time points: less than 24 hours; 2-3 weeks after stroke and 2 months after stroke. Both MRI scan and NIH stroke scale (NIHSS) were acquired for each patient at all three time points. Oxygen saturation changes were derived from phase values differences (Δφ) measured over 10 veins from each hemisphere for all 10 patients over 3 time points. The correlation of oxygen saturation and NIHSS was further evaluated.

Results: The stroke affected side of the brain showed moderate (r = -0.62) to strong (r = -0.70) correlation between the oxygenation change and NIHSS change. The oxygen saturation change from the normal side of the brain had essentially no association with recovery (r = -0.02 and-0.31). The results suggest that increases in oxygen saturation correspond to improved outcome and reductions in oxygen saturation correspond to worse outcome.

Conclusion: High resolution SWI provided a novel method to measure changes in oxygenation change of the human brain in vivo. By using the phase values from the veins, both spatial and temporal information can be found that relates to patient outcome post stroke.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Phase profile showing the susceptibility change from the tissue and vessel.
We measure Δφa, Δφb and Δφc, so the average phase change cross the vessel formula image.
Figure 2
Figure 2. Vessel selection for a stroke patient.
a) maximum intensity projection over 3 slices of T2 weighted imaging shows stroke affected area (red arrow). b), c) and d) minimum intensity projections over 20 slices of SWI processed phase images showing the locations of the 10 measured vessels (red lines) for each hemisphere at (b)<24 hours, (c) 2 to 3 weeks after stroke, and (d) 2 months after the onset of stroke. SWI shows hypointense signal on the stroke side of the brain (c,d), and also a hemorrhage (yellow circle) in the left putamen in the second and third scans (c,d).
Figure 3
Figure 3. Phase profiles over the SWI filtered phase images corresponding to the three MRI scans (a)<24 hours, (b) 2–3 weeks after stroke, and (c) 2 months after the onset of stroke.
Figure 4
Figure 4. Oxygenation changes vs. NIHSS changes scatter plots with error bar of both hemispheres for ten stroke patients.
A) formula image vs. ΔNIHSS2,1 for the stroke hemisphere; B) formula image vs. ΔNIHSS3,2 for the stroke hemisphere; C) formula image vs. ΔNIHSS2,1 for the non-stroke hemisphere; D) formula image vs. ΔNIHSS3,2 for the non-stroke hemisphere. Here formula image and formula image are the average over 10 vessels for each hemisphere.
See this image and copyright information in PMC

References

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