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

Table 2

Equivalence tests for the distribution on the type of stroke classification between reading systems.

Variable	δ (%)	Mean	SE	()% CI for equivalence testing			value ()	H	(%)
				Lower	Upper
Without lesion	10		0.015		0.003		<0.001	Ha	4.5
Hemorrhagic lesion	10		0.005		0.002		<0.001	Ha	1.6
Acute ischemic lesion	10		0.017		0.087		0.0079	Ha	8.7
Chronic ischemic lesion	10		0.011				<0.001	Ha	4.8
Overall ischemic lesion	10	0.028	0.015	0.003	0.052		0.0000	Ha	5.2

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., : δ required for equivalence (i.e., ). Ho: ; Ha: . comparison was calculated by six radiologists and two devices.