Table 2.

Tumour and ring characteristics stratified by difference in distance between tumour margin and tantalum ring (DTR) for tumours where DTR was measured by both transillumination and ultrasound, Group 2B

Group 2B
Feature	All tantalum rings with <2 mm difference in DTR	At least 1 tantalum ring per tumour with ≥2 mm difference in DTR	p-valuea	Total
	[n = 14 tumours, 25 rings]	[n = 7 tumours, 12 rings]		[n = 21 tumours]
Tumour size
Mean base, mm [median, range]	10.3 [10.3, 5.5–14.6]	13.9 [13.9, 7.8–21.1]	0.047	10.7 [10.4, 4.1–21.1]
Mean thickness, mm [median, range]	4.0 [3.0, 1.7–11.9]	6.4 [5.6, 2.0–14.3]	0.2	4.0 [2.8, 1.7–14.3]
Tumour epicentre location (%)
Macula	2 (14)	0		11 (20)
Macula to equator	7 (50)	4 (57)	0.9b	22 (41)
Equator to ora serrata	4 (29)	3 (43)		17 (31)
Ciliary body	1 (7)	0		4 (7)
Tumour pigment, % [median, range]	62 [65, 15–90]	71 [70, 40–100]	0.4	66 [70, 5–100]
Mean distance of ring to limbus, mm [median, range]	14.1 [14.8, 0.5–21]	14.7 [14.8, 4.0–20]	0.5	14.3 [14.8, 0.5–21]

TI transillumination, US ultrasound, DTR distance between tumour margin and tantalum ring

^aIndependent t-test

^bFisher exact test