Table 5.

Significance p-values for measuring a 20% reduction in [¹¹C]DASB BP_ND in simulated studies with a cohort of 25 controls and 25 patients. The p-values were obtained comparing simulated controls and patients of 25, 15, and 10 subjects per group, respectively. The mean values are the p-values averaged across the different BP_ND values. For this simulation study, it was assumed that five regions-of-interest were being evaluated, where the control binding levels for the five regions were BP_ND = 0.25, 0.5, 1.0, 2.0, 4.0. Patient populations were then simulated with a 20% reduction in binding in one of the regions. Thus to evaluate the ability to measure a 20% change in the smallest binding region, one patient group had BP_ND = 0.20, 0.5, 1.0, 2.0, 4.0. Similarly, there were patient groups with the following BP levels: (0.25, 0.4, 1.0, 2.0, 4.0); (0.25, 0.5, 0.8, 2.0, 4.0); (0.25, 0.5, 1.0, 1.6, 4.0); (0.25, 0.5, 1.0, 2.0, 3.2). For each group, 25 patients were simulated by generating 25 different BP_ND values that had a coefficient of variation of about 35%, which is comparable to the between subject variability observed in our [¹¹C]DASB studies of HIV dementia. The mean of the simulated BP_ND values was set to the desired value. For each patient simulation, the set of five time-activity curves were simulated at three different noise levels. The control and patient studies were then evaluated using five different methods for estimating BP_ND as described in the text. An unpaired 2-tailed students t-test was applied to test for significant differences in BP_ND.

BPND	SRTM			SRTM2			SRTMC			Zhou			Zhou2
	n = 25	n = 15	n = 10	n = 25	n = 15	n = 10	n = 25	n = 15	n = 10	n = 25	n = 15	n = 10	n = 25	n = 15	n = 10
Low noise (α = 0.02)
0.25	0.075	0.131	0.180	0.033	0.121	0.211	0.033	0.073	0.217	0.024	0.094	0.177	0.031	0.095	0.116
0.5	0.030	0.142	0.262	0.025	0.141	0.273	0.026	0.125	0.271	0.029	0.151	0.282	0.025	0.064	0.335
1	0.025	0.155	0.278	0.013	0.158	0.275	0.031	0.159	0.292	0.021	0.184	0.308	0.020	0.361	0.396
2	0.022	0.107	0.206	0.016	0.092	0.183	0.024	0.104	0.241	0.027	0.126	0.249	0.031	0.130	0.160
4	0.057	0.175	0.299	0.049	0.144	0.248	0.071	0.198	0.339	0.048	0.249	0.404	0.086	0.274	0.312
Mean	0.042	0.142	0.245	0.027	0.131	0.238	0.037	0.132	0.272	0.030	0.161	0.284	0.039	0.185	0.264
Medium noise (α = 0.03)
0.25	0.025	0.109	0.203	0.034	0.132	0.231	0.033	0.075	0.224	0.038	0.122	0.208	0.045	0.115	0.141
0.5	0.030	0.169	0.276	0.029	0.144	0.283	0.033	0.146	0.299	0.030	0.156	0.275	0.031	0.086	0.256
1	0.068	0.218	0.337	0.037	0.157	0.262	0.031	0.158	0.274	0.053	0.221	0.342	0.034	0.408	0.428
2	0.007	0.047	0.110	0.011	0.065	0.148	0.017	0.076	0.211	0.015	0.081	0.178	0.038	0.148	0.169
4	0.050	0.099	0.125	0.013	0.064	0.117	0.006	0.045	0.129	0.467	0.559	0.572	0.030	0.122	0.198
Mean	0.036	0.128	0.210	0.025	0.112	0.208	0.024	0.100	0.227	0.121	0.228	0.315	0.035	0.176	0.238
High noise (α = 0.04)
0.25	0.323	0.248	0.260	0.060	0.166	0.260	0.078	0.132	0.287	0.069	0.175	0.271	0.075	0.182	0.280
0.5	0.323	0.244	0.271	0.018	0.095	0.204	0.032	0.145	0.280	0.019	0.102	0.200	0.023	0.121	0.235
1	0.107	0.264	0.386	0.029	0.158	0.270	0.039	0.165	0.295	0.050	0.232	0.355	0.019	0.154	0.269
2	0.077	0.192	0.291	0.047	0.146	0.256	0.097	0.238	0.355	0.062	0.240	0.302	0.072	0.228	0.348
4	0.062	0.184	0.276	0.104	0.246	0.330	0.045	0.182	0.292	0.208	0.354	0.446	0.034	0.144	0.255
Mean	0.178	0.226	0.297	0.052	0.162	0.264	0.058	0.172	0.302	0.082	0.221	0.315	0.045	0.166	0.277