Table 2.

Absolute and relative frequencies of images in which the target structures were identified (easily identifiable) or unidentified (unidentifiable + inconclusive) with the T1 GRE and T1 IR GRE techniques, in six different scenarios.

			T1GRE
Scenario	T1 IR GRE		Unidentifiable + inconclusive	Identifiable	Total
1) All observations (n = 15,000)	Unidentifiable + inconclusive	n	582	90	673
		%	7.8%	1.2%	9.0%
	Identifiable	n	256	6,571	6,827
		%	3.4%	87.6%	91.0%
	Total	n	838	6,662	7,500
		%	11.2%	88.8%	100.0%
2) Intraobserver analysis (n = 9,000)	Unidentifiable + inconclusive	n	374	53	427
		%	8.3%	1.2%	9.5%
	Identifiable	n	176	3,897	4,073
		%	3.9%	86.6%	90.5%
	Total	n	550	3,950	4,500
		%	12.2%	87.8%	100.0%
3) Interobserver analysis (n = 9,000)	Unidentifiable + inconclusive	n	341	51	392
		%	7.6%	1.1%	8.7%
	Identifiable	n	145	3,963	4,108
		%	3.2%	88.1%	91.3%
	Total	n	486	4,014	4,500
		%	10.8%	89.2%	100.0%
4) First evaluation of observer 1 (n = 3,000)	Unidentifiable + inconclusive	n	133	13	146
		%	8.9%	0.9%	9.7%
	Identifiable	n	65	1,289	1,354
		%	4.3%	85.9%	90.3%
	Total	n	198	1,302	1,500
		%	13.2%	86.8%	100.0%
5) Evaluation of observer 2 (n = 3,000)	Unidentifiable + inconclusive	n	103	23	126
		%	6.9%	1.5%	8.4%
	Identifiable	n	48	1,326	1,374
		%	3.2%	88.4%	91.6%
	Total	n	151	1,349	1,500
		%	10.1%	89.9%	100.0%
6) Evaluation of observer 3 (n = 3,000)	Unidentifiable + inconclusive	n	105	15	120
		%	7.0%	1.0%	8.0%
	Identifiable	n	32	1,348	1,380
		%	2.1%	89.9%	92.0%
	Total	n	137	1,363	1,500
		%	9.1%	90.9%	100.0%

n, absolute frequency; %, relative frequency. Scenario 1 (McNemar: χ² = 77.51; p-value = 0.000); Scenario 2 (McNemar: χ² = 64.97; p-value = 0.000); Scenario 3 (McNemar: χ² = 44.12; p-value = 0.000); Scenario 4 (McNemar: χ² = 33.35; p-value = 0.000); Scenario 5 (McNemar: χ² = 8.11; p-value = 0.003); Scenario 6 (McNemar: χ² = 5.48; p-value = 0.020).