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Figure 4. A graph showing the change in contrast concentration against time in a single voxel of normal grey matter of a normal brain. The data collection has been performed with a deliberately degraded acquisition sequence in order to reduce contrast to noise ratio in the data. A direct comparison with Figure 1 shows significantly lower signal to noise ratio in these data. Despite this the curve fitting programme has derived an optimal fit which will be used the calculation of vascular parameters. However, if fitting error is calculated as described in the text then this curve fit result will be associated with very broad confidence intervals.
