Table 3. Conspicuity scores.

	T1w	T2w	ceT1w	SWI	FLAIR	DWI
Lesions at first diagnosis MRI
n of 720	699	706	712	496	673	510
mean CS	1.77	1.82	2.91	1.94	2.32	1.42
±SD	1.14	1.17	0.30	1.22	1.05	1.27
n(CS 0)	124 (17.7%)	143 (20.3%)	0 (0%)	104 (21.0%)	72 (10.7%)	191 (37.5%)
n(CS 1)	179 (25.6%)	132 (18.7%)	2 (0.3%)	71 (14.3%)	83 (12.3%)	72 (14.1%)
n(CS 2)	131 (18.7%)	143 (20.3%)	60 (8.4%)	72 (14.5%)	75 (11.1%)	91 (17.8%)
n(CS 3)	265 (37.9%)	288 (40.8%)	650 (91.3%)	249 (50.2%)	443 (65.8%)	156 (30.6%)
Lesions at pre-diagnosis MRI
n of 33	33	33	33	23	32	24
mean CS	0.48	0.18	1.82	0.39	0.56	0.17
±SD	0.83	0.64	0.88	0.94	1.01	0.64
n(CS 0)	22 (66.7%)	30 (90.9%)	0 (0%)	19 (82.6%)	22 (68.8%)	22 (91.7%)
n(CS 1)	8 (24.2%)	1 (3.0%)	16 (48.5%)	1 (4.3%)	6 (18.8%)	1 (4.2%)
n(CS 2)	1 (3.0%)	1 (3.0%)	7 (21.2%)	1 (4.3%)	0 (0%)	0 (0%)
n(CS 3)	2 (6.1%)	1 (3.0%)	10 (30.3%)	2 (8.7%)	4 (12.5%)	1 (4.2%)
Lesions ≤ 5 mm diameter at first diagnosis MRI
n	385	390	391	270	377	293
mean CS	1.33	1.2	2.72	1.46	1.77	0.83
±SD	1.15	1.11	0.56	1.29	1.22	1.1
Leptomeningeal lesions
n of 720	77	79	76	70	77	63
mean CS	1.84	1.29	2.82	1.33	2.17	0.87
±SD	1.12	1.15	0.48	1.34	1.12	1.08
Pachymeningeal lesions
n of 720	18	19	19	17	19	17
mean CS	2.06	2.11	3.00	2.35	2.58	1.82
±SD	1.00	1.05	0.00	1.06	0.90	1.19
Amelanotic lesions
n of 49	47	48	47	28	44	25
mean CS	1.44	1.98	2.90	2.30	2.53	1.65
±SD	1.21	1.00	0.31	0.97	0.94	1.27
Melanotic lesions
n of 169	159	167	164	130	154	124
mean CS	1.84	1.63	2.88	1.98	2.17	1.48
±SD	1.13	1.22	0.32	1.23	1.13	1.30

Abbr.: n, number; CS, conspicuity score; SD, standard deviation; T1w, non-enhanced T1-weighted; T2w, T2-weighted; ceT1w, contrast-enhanced T1-weighted; SWI, susceptibility-weighted imaging; FLAIR, fluid-attenuated inversion recovery; DWI, diffusion-weighted imaging. Total number of lesions with confirmed melanotic / amelanotic primary tumor histology was 218/720 lesions overall.