Comparison of DWI and FLAIR DWI b = 1500 s/mm2 images
| Tissue and Technique | SI | SNR | CNR | |||
|---|---|---|---|---|---|---|
| Mean | σ | Mean | σ | Mean | σ | |
| Air | ||||||
| DWI | 48.4 | 15.2 | ||||
| FLAIR DWI | 54.0 | 18.5 | ||||
| % Difference | −11.6 | |||||
| CSF | ||||||
| DWI | 57.9 | 24.6 | 2.2 | 0.5 | −23.3 | 5.2 |
| FLAIR DWI | 48.0 | 18.3 | 1.7 | 0.3 | −14.9 | 3.9 |
| % Difference | 17.1 | 22.7 | 36.1 | |||
| Globus pallidus | ||||||
| DWI | 140.3 | 61.7 | 5.5 | 1.8 | −20.0 | 4.2 |
| FLAIR DWI | 120.0 | 49.5 | 4.5 | 1.3 | −12.2 | 3.7 |
| % Difference | 14.5 | 18.2 | 39.0 | |||
| Gray matter | ||||||
| DWI | 336.1 | 117.5 | 13.2 | 2.9 | −12.2 | 3.5 |
| FLAIR DWI | 236.4 | 78.4 | 8.8 | 1.9 | −7.8 | 3.5 |
| % Difference | 29.7 | 33.3 | 36.1 | |||
| Insular cortex | ||||||
| DWI | 409.8 | 148.9 | 15.9 | 3.1 | −9.6 | 4.5 |
| FLAIR DWI | 255.5 | 81.8 | 9.5 | 1.9 | −7.1 | 3.8 |
| % Difference | 37.7 | 40.3 | 26.0 | |||
| Ischemic tissue | ||||||
| DWI | 654.3 | 237.0 | 25.5 | 5.1 | ||
| FLAIR DWI | 456.7 | 183.6 | 16.6 | 4.0 | ||
| % Difference | 30.2 | 34.9 | ||||
| Putamen | ||||||
| DWI | 229.0 | 98.5 | 8.8 | 2.3 | −16.6 | 4.9 |
| FLAIR DWI | 155.3 | 61.3 | 5.8 | 1.7 | −10.8 | 3.8 |
| % Difference | 32.2 | 34.1 | 34.9 | |||
| White matter | ||||||
| DWI | 407.5 | 148.0 | 16.0 | 3.8 | −9.5 | 4.3 |
| FLAIR DWI | 346.7 | 124.4 | 12.8 | 2.5 | −3.8 | 3.2 |
| % Difference | 14.9 | 20.0 | 60.0 | |||
Note.—One-way ANOVA of DWI and FLAIR DWI for each tissue showed that all means differed significantly with (P < .001) except for the mean SI and SNR of the globus pallidus (P < .05) and the CNR of the insula (P < .05). CNRs reported are negative because the ischemic tissue has the most intense signal on the image.