Table 1.

Distribution of centers per country and average number of treated DLGG

	Number of centers responded	%	Avg. no of LGG per center and year	Range
Country of practice
Germany	40	31	20	5–50
Italy	14	11	10	5–90
France	9	6	25	3–100
Switzerland	8	7	20	5–100
United Kingdom	8	6	30	10–60
Austria	7	5	20	6–40
Spain	7	5	5	3–20
Netherlands	6	5	25	15–40
Portugal	4	3	20	2–20
Belgium	3	2	15	15–30
Greece	3	2	25	10–30
Poland	3	2	25	20–30
Czech Republic	2	2	15	15
Russian Federation	2	2	55	50–60
Serbia	2	2	15	10–20
Sweden	2	2	20	20
Bulgaria	1	< 1	10	10
Denmark	1	< 1	20	20
Hungary	1	< 1	n/a	n/a
Lithuania	1	< 1	30	30
Norway	1	< 1	30	30
Romania	1	< 1	10	10
Turkey	1	< 1	20	20
Ukraine	1	< 1	5	5
Use of 3T imaging	128
Always	29	22.8
If available	59	46.5
Only 1.5T	39	30.7
Identical MR scanner
Yes	25	20.0
No	24	19.2
Mostly yes	72	57.6
Mostly no	4	3.2

			Total number of patients
Slice thickness of T1 imaging (mm)
< 1.5	66	53.7	–	1585
1.6–3	44	35.8	–	781
> 3	13	10.6	–	356
Slice thickness of T2 imaging (mm)
< 1.5	40	32.8	–	1027
1.6–3	54	44.3	–	1133
> 3	28	23.0	–	542
Imaging intervals in relation to the amount of residual disease
No remnant (weeks)
< 12	3	2.4
12–24	87	68.5
> 24	15	11.8
52	4	3.1
< 10 ml remnant (weeks)
< 12	4	3.1
12–24	91	71.7
> 24	12	9.4
52	0	0.0
11–15 ml remnant (weeks)
< 12	4	3.1
12–24	95	74.8
> 24	9	7.1
52	0	0.0
> 15 ml remnant (weeks)
< 12	7	5.5
12–24	97	76.4
> 24	4	3.1
52	0	0.0
Unresectable LGG (weeks)
< 12	1	0.8
12–24	97	76.4
> 24	6	4.7
52	3	2.4

Use of imaging infrastructure and average slice thickness. Imaging intervals with respect to the amount of residual disease