Table 2. Regression coefficients for relation of grey level variation to MAR, position and peak kilovoltage.
Regression coefficient (SE) |
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Reference (peripheral without MAR) | Profile AB | Profile BC | Profile CA | |
Level (kVp=70) | 47.61 (1.50) * | 83.63 (2.09) * | 64.40 (2.06) * | |
Slope | −0.40 (0.09) * | −0.83 (0.12) * | −0.57 (0.10) * | |
Factor | Effect | |||
MAR | Change in level (kVp=70) | −26.63 (1.73) * | −9.40 (2.41) ** | −43.80 (2.92) * |
Central position | Change in level (kVp=70) | −2.05 (1.73) | 1.82 (2.41) | −11.90 (2.92) ** |
Change in slope | 0.30 (0.12) *** | 0.39 (0.17) *** | 0.59 (0.15) ** | |
MAR and central position | Change in level (kVp=70) | 15.30 (4.12) ** | ||
R2 | 0.95 | 0.84 | 0.96 |
MAR, metal artefact reduction; SE, standard error.
* p≤0.001.
** p≤0.01.
*** p≤0.05.