. Author manuscript; available in PMC: 2013 Feb 1.

Published in final edited form as: Acad Radiol. 2011 Nov 21;19(2):184–190. doi: 10.1016/j.acra.2011.10.008

Table 2.

Selected power calculations for randomized trial to detect a true effect of 20% difference in average percent FDG uptake change between two treatments (80% power, Type I error rate (α) = 0.05).

		Power
Trial Scenario	N	1^st tertile SUV_baseline≤3 50% sens.^*	2^nd tertile 3≤SUV_baseline≤5.2 70% sens.^*	3^rd tertile SUV_baseline>5.2 90% sens.^*	kinetic modeling 100% sens.^*
Single site, σ^† =10%	20	61%	88%	98%	99%
Single site, σ^† =10%	30	78%	97%	99%	99%

Multi-center, σ^† =20%	50	42%	70%	89%	94%
Multi-center, σ^† =20%	100	71%	94%	99%	99%

Muiti-center, σ^† =40%	100	24%	42%	61%	71%
Muiti-center, σ^† =40%	300	58%	86%	97%	99%

Sensitivity to a true effect size of 20 percentage point difference in FDG uptake change

^†

Standard deviation of percent FDG uptake change, with larger values attributable to greater measurement error