Ruling Out Brain CT Contraindications prior to Intravenous Thrombolysis: Diagnostic Equivalence between a Primary Interpretation Workstation and a Mobile Tablet Computer

Table 4

Equivalence tests for the diagnostic variables and reading time.

Variable	δ	Mean	SE	()% CI for equivalence testing			value ()	H
				Lower	Upper
ASPECTS ≤ 6	10.0%		0.011		0.017		<0.001	Ha	2.1%
Presence of imaging contraindications to the tPA administration	10.0%	0.020	0.028		0.065		0.0018	Ha	6.5%
Presence of HMCA	10.0%		0.019				0.0010	Ha	7.2%
Reading time	15 s	3.6 s	6.2		13.7		0.0318	Ha	13.7 s

SE: Standard error of the mean difference, CI: confidence Interval; Ho: null hypothesis, Ha: alternative hypothesis for testing equivalence, α: significance of the test (0.05), δ: difference of the means allowed to achieve equivalence, : test for difference of compared devices, that is, , H: retained hypothesis equivalence at δ level, “Ha” indicates equivalence achieved and “–” indicates fail to reject Ho., required for equivalence (i.e., ); Ho: ; Ha: . comparison was calculated for six radiologists and two devices.