Table 2. Summary of perfusion-weighted signal to noise ratio (SNRdM) and CBF calculated from data before and after application of spatial smoothing.
|
SNRdM
|
CBF (SNRdM > 1)
|
|||
|---|---|---|---|---|
| Degree of smoothing | WM | GM | WM | GM |
| w/o smoothing | 1.9 +/– 0.4 | 7.3 +/– 2.4 | 27.5 +/– 1.6 | 63.9 +/– 1.8 |
| FWHM = 3 mm | 6.2 +/– 1.3 (4.8 +/– 0.9) | 19.6 +/– 6.8 | 24.4 +/– 1.6 (18.6 +/– 1.6) | 53.8 +/– 3.5 |
| FWHM = 8 mm | 24.0 +/– 6.3 (14.2 +/– 3.6) | 46.3 +/– 16.2 | 25.3 +/– 3.5 (15.8 +/– 3.5) | 46.0 +/– 3.9 |
Pre-smoothing masks were applied to both white matter (WM) and gray matter (GM). Post-smoothing masks were also applied to WM with the results shown in parentheses. CBF is in units of ml/100ml/min. Data from 10 subjects are averaged and presented as mean +/- standard deviation.