fig 5.

Range of deep white matter:superficial oxygen extraction fraction ratios for the nine patients with high oxygen extraction fraction in superficial regions compared with their contralateral hemispheres and with normal hemispheres is similar. Two patients had deep white matter:superficial oxygen extraction fraction ratios beyond the range seen in the contralateral hemispheres but within the normal range. As with figure 2, the ratio of deep white matter:superficial oxygen extraction fraction is shown on the y axis and the ratios of the three groups of volunteers are shown on the x axis. The boxes indicate the 95% confidence limits for the oxygen extraction fraction ratios. The lines within the boxes indicate the median values, and the bars above and below the boxes indicate the 99% confidence limits. Patients with oxygen extraction fraction values beyond the 99% confidence limits are represented with black circles.