Table 2. Results of objective image quality analysis.
| Group | Attention (HU) | Noise (HU) | |||||
|---|---|---|---|---|---|---|---|
| ICA | MCA | BA | ICA | MCA | BA | ||
| A (n=31), mean ± standard deviation |
548±112 | 453±118 | 431±99 | 25±16 | 45±28 | 47±21 | |
| B (n=31), mean ± standard deviation |
454±85 | 388±70 | 360±83 | 33±85 | 39±27 | 44±27 | |
| t value | −5.952 | 4.818 | 4.214 | −7.345 | 1.896 | 0.741 | |
| P value | <0.01 | <0.01 | <0.01 | 0.466 | 0.063 | 0.465 | |
A, CTA-DF-CTP; B, conventional CTA. HU, Hounsfield units; ICA, internal carotid artery; MCA, middle cerebral artery; BA, basilar artery; CTA-DF-CTP, computed tomography angiography derived from computed tomography perfusion; CTA, computed tomography angiography.