3 Tesla multiparametric MRI for GTV-definition of Dominant Intraprostatic Lesions in patients with Prostate Cancer – an interobserver variability study

Table 5 Kappa-indices throughout the different MRI-sequences

	Pat. No. 1	Pat. No. 2	Pat. No. 3	Pat. No. 4	Pat. No. 5
T2w	Kappa index	Kappa index	Kappa index	Kappa index	Kappa index
Reference observer	1	1	1	1	1
Observer A	0,639	0,469	0,532	0,496	0,671
Observer B	0,736	0,695	0,724	0,471	0,646
Observer C	0,720	0,549	0,653	0,634	0,691
Observer D	0,652	0,762	0,579	0,748	0,605
Observer E	0,759	0,511	0,539	0,475	0,272
T2w Rating-score quotient	1,67	1,83	1,67	1,83	1,83
Diffusion weighed (DWI)	Kappa index	Kappa index	Kappa index	Kappa index	Kappa index
Reference observer	1	1	1	1	1
Observer A	0,561	0,315	0,222	0,593	0,603
Observer B	0,727	0,528	0,304	0,648	0,497
Observer C	0,582	0,568	0,337	0,477	0,563
Observer D	0,586	0,687	0,358	0,588	0,555
Observer E	0,692	0,470	0,237	0,343	0,672
DWI Rating-score quotient	2,17	2,83	3	2,17	2,83
Dynamic contrast enhanced (DCE)	Kappa index	Kappa index	Kappa index	Kappa index	Kappa index
Reference observer	1	1	1	1	1
Observer A	0,254	0,641	0,669	0,471	0,563
Observer B	0,737	0,653	0,640	0,717	0,687
Observer C	0,710	0,691	0,651	0,775	0,409
Observer D	0,476	0,651	0,746	0,798	0,679
Observer E	0,000	0,677	0,691	0,643	0,543
DCE Rating-score quotient	1,67	1,5	1,33	1,33	1,83

KI = Kappa-Index. KI-values > 0.6 are bold and regarded as substantial agreement respectively. KI-values > 0.7 indicate excellent agreement with the reference volume per definition (please methods section). Rating score quotient is the average of rating points assigned by all observers (including reference) (1 = easy to delineate, 2 = minor difficulties, 3 = major difficulties).

ISSN: 1748-717X