. Author manuscript; available in PMC: 2016 Jun 1.

Published in final edited form as: Magn Reson Med. 2015 Jul 18;75(6):2265–2277. doi: 10.1002/mrm.25729

Table 2.

T₁ Relaxation in Volunteers at 7T and 3T Based on Biexponential and Monoexponential Fits to 13 IR-FSE Images

Volunteer	T_1L (ms)	T_1S (ms)	Short T₁, Weight, w_S	T₁* (ms)	% Difference (T₁*/T_1L − 1)^a	% Voxels
Volunteer	T_1L (ms)	T_1S (ms)	Short T₁, Weight, w_S	T₁* (ms)	% Difference (T₁*/T_1L − 1)^a	P < 0.05	P < 0.01
7T
#1	1342 ± 60	53 ± 12	11% ± 2%	1161 ± 60	−13%	99.5%	98.8%
#2	1347 ± 64	51 ± 19	10% ± 2%	1173 ± 39	−13%	94.8%	80.0%
#3	1331 ± 77	61 ± 12	11% ± 2%	1106 ± 95	−17%	91.1%	86.9%
#4	1374 ± 46	64 ± 14	12% ± 2%	1162 ± 38	−18%	97.2%	93.3%
Mean^b	1349 ± 18	57 ± 6	11% ± 1%	1151 ± 30	−15% ± 3%	96% ± 4%	90% ± 8%
3T
#1	949 ± 54	54 ± 40	7% ± 2%	906 ± 43	−4%	50.8%	27.5%
#2	928 ± 37	47 ± 48	10% ± 2%	864 ± 26	−7%	43.0%	14.8%
#3	926 ± 79	49 ± 64	9% ± 3%	869 ± 60	−6%	43.0%	19.3%
#4	952 ± 67	42 ± 43	8% ± 2%	887 ± 40	−7%	44.3%	20.2%
Mean^b	939 ± 14	48 ± 5	9% ± 1%	882 ± 19	−6% ± 1%	45% ± 4%	20% ± 5%

Values are for an ROI encompassing all of the WM in an axial slice through the basal ganglia. Subjects #2–4 are the same volunteer at both field strengths.

Gives the error in the fitted T₁* seen in monoexponential fits to all data compared with the biexponential long component T_1L.

Mean ± standard deviation of the mean across all volunteers at that field strength.