Table 1. Group characteristics.

Values are means (with standard deviation). Equal variances not assumed. All test are parametric t-tests except for † indicating non-parametric Wilcoxon rank sum test

	n total	n females	Age (Years)	Weight (Kg)	DPN dose injected (MBq)	H2O dose injected (MBq)	Head motion	Intra-scan pain ratings	Thermal pain threshold (W cm-2)
Arthritis patients	17	12	57.5 (12.1)	83.1 (21.0)	490.0 (62.3)	606.7 (22.3)	3.6 (3.3)	2.5 (2.0)	3.9 (1.5)
Healthy controls	9	3	45.4 (7.5)	78.8 (16.2)	505.0 (33.0)	583.4 (30.7)	1.6 (1.8)	1.5 (1.4)	4.0 (1.9)
Independent samples test p statistic		0.08	0.004	0.59	0.26	0.07	0.1456†	0.18	0.76