Study of inter- and intra-observer reproducibility in the interpretation of [18F]choline PET/CT examinations in patients suffering from biochemically recurrent prostate cancer following curative treatment

EJNMMI Research

Table 3 Intra-observer reproducibility of binary interpretations (negative/benign/non-significant or positive/malignant/high-risk

Locations	Intra-observer agreement between first and second interpretation
	kappa [confidence interval]
	Senior 1 (CG)	Senior 2 (CC)	Junior 1 (JD)	Junior 2 (CP)
Prostate and bed	0.493 [0.237 to 0.749]	0.789 [0.629 to 0.949]	0.798 [0.645 to 0.951]	0.534 [0.312 to 0.755]
Prostatectomy bed	NA	NA	NA	NA
Prostate	0.528 [0.252 to 0.805]	0.741 [0.561 to 0.920]	0.755 [0.585 to 0.925]	0.548 [0.320 to 0.776]
Pelvic LN	0.812 [0.656 to 0.967]	1.000 [1.000 to 1.000]	0.925 [0.823 to 1.000]	0.889 [0.766 to 1.000]
R hemi-pelvic LN	0.715 [0.485 to 0.944]	0.932 [0.799 to 1.000]	0.777 [0.569 to 0.896]	0.839 [0.662 to 1.000]
L hemi-pelvic LN	0.658 [0.380 to 0.935]	0.795 [0.571 to 1.000]	0.870 [0.693 to 1.000]	0.640[0.376 to 0.904]
PET overall conclusion	0.626 [0.432 to 0.820]	0.741 [0.561 to 0.920]	0.574 [0.368 to 0.780]	0.645 [0.421 to 0.869]

The inter-observer reproducibility is indicated by kappa (κ) (and confidence interval) for different anatomic regions. κ > 0.80 is excellent; 0.61 < κ < 0.80 is good; 0.60 < κ < 0.41 is moderate; κ < 0.40 is average. LN, lymph nodes; R, right; L, left.