Table 4.

Wall invasion by inferior vena cava thrombus on MRI versus invasion determined at surgery

Observer 1 MRI	Surgery
	Wall invasion	Absence of wall invasion
Wall invasion	24	1
Absence of wall invasion	2	21
Observer 2 MRI	Surgery
	Wall invasion	Absence of wall invasion
Wall invasion	25	3
Absence of wall invasion	1	19
Observers 1 + 2 MRI	Surgery
	Wall invasion	Absence of wall invasion
Wall invasion	24	3
Absence of wall invasion	2	19

In three cases, the two observers assessed the presence or absence of invasion differently. In case of a differing assessment, the opposite of the reference standard (intraoperative finding) was assumed in order to avoid an overestimation of the diagnostic performance. This combined assessment (observers 1 + 2) is shown below