Table 2.
CNR analysis.
| Region (n of ROI) | CNR values | R values | |||||
|---|---|---|---|---|---|---|---|
| DVA100 | DSA100 | DVA30 | DSA30 | DVA100/DSA100 | DVA30/DSA30 | DVA30/DSA100 | |
| Abdominal n = 5160 | 22.4 (14.0–34.9) | 8.2 (5.6–11.2) | 15.9 (10.4–24.1) | 6.3 (4.2–8.2) | 2.8 (2.1–3.6) | 2.8 (2.1–3.6) | 2.0 (1.5–2.9) |
| Wilcoxon p < 0.001 | Wilcoxon p < 0.001 | ||||||
| Mann–Whitney p < 0.001 | |||||||
| Femoral n = 7504 | 23.8 (14.0–42.2) | 11.8 (7.1–17.7) | 21.1 (13.0–33.5) | 8.4 (5.5–12.7) | 2.2 (1.6–2.8) | 2.7 (1.9–3.5) | 1.9 (1.4–2.5) |
| Wilcoxon p < 0.001 | Wilcoxon p < 0.001 | ||||||
| Mann–Whitney p < 0.001 | |||||||
| Crural n = 6534 | 16.8 (11.2–26.0) | 5.7 (3.9–8.1) | 12.8 (8.2–19.8) | 4.1 (3.0–6.2) | 3.0 (2.3–3.8) | 3.1 (2.3–4.0) | 2.3 (1.7–3.0) |
| Wilcoxon p < 0.001 | Wilcoxon p < 0.001 | ||||||
| Mann–Whitney p < 0.001 | |||||||
| Overall n = 19,198 | 20.9 (12.6–34.0) | 8.0 (5.1–12.8) | 16.0 (10.2–25.9) | 6.1 (3.9–9.0) | 2.6 (2.0–3.4) | 2.8 (2.1–3.7) | 2.0 (1.5–2.8) |
| Wilcoxon p < 0.001 | Wilcoxon p < 0.001 | ||||||
| Mann–Whitney p < 0.001 | |||||||
Values expressed as the median and the interquartile range (Q1–Q3). Wilcoxon signed rank test and Mann Whitney U test were used to compare paired and unpaired data sets, respectively. ROI: Region of Interest; DVA: Digital Variance Angiography, DSA: Digital Subtraction Angiography. The index defines the applied protocol, 100: normal dose, 30: low-dose.