|
The SD and required sample size to show a clinical change with a power of 90% and an α error of 0.05 to detect a change of the Ved and Ves of 10 ml and an absolute change in the EF of 3% for SA images before and after registration.1 |
|||||
| SA images before registration |
SA images after registration |
||||
| SD |
Sample size |
SD |
Sample size |
Reduction in sample size |
|
|
|
|||||
| 10 ml change in Ved |
5.8 |
7.1 (8) |
4.2 |
3.7 (4) |
48% |
| 10 ml change in Ves |
3.4 |
2.4 (3) |
1.8 |
0.7 (1) |
71% |
| 3% absolute change in EF |
1.9 |
8.4 (9) |
1.3 |
3.9 (4) |
53% |
|
1SD = standard deviation, SA = short axis, Ved = end-diastolic left ventricular volume, Ves = end-systolic left ventricular volume, EF = ejection fraction. | |||||
Chandler et al. Journal of Cardiovascular Magnetic Resonance 2008 10:13 doi:10.1186/1532-429X-10-13 |
|||||