Table 2.

DTI of the genu and splenium of the corpus callosum in heterozygous dogs (i.e., control, or CTL) dogs (n = 4), untreated dogs affected with mucopolysaccharidosis type I (MPS, n = 9) and MPS I dogs treated with intrathecal recombinant human alpha-l-iduronidase every three months from age 4m to 21m (MTr, n = 4). Metrics included fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (Ax Diff), and radial diffusivity (Rad Diff). Each dog was scanned twice and the results averaged. Data are expressed as means of the means for each animal ± SD. Statistical analysis was performed using ANOVA with Tukey posthoc test.

	FA	ADC	Ax Diff	Rad Diff
Genu
CTL	0.437 ± 0.0453	8.74 10−4 ± 2.18×10−4	1.29×10−3 ± 3.01×10−4	6.66×10−4 ± 1.79×10−4
MPS	0.348 ± 0.0318*	1.05×10−3 ± 2.25×10−4	1.44×10−3 ± 3.23×10−4	8.60×10−4 ± 1.80×10−4
MTr	0.402 ± 0.0428	9.18×10−4 ± 1.31×10−4	1.32×10−3 ± 1.63×10−4	7.17×10−4 ± 1.21×10−4
Splenium
CTL	0.514 ± 0.0295	8.29×10−4 ± 6.68×10−5	1.37×10−3 ± 1.04×10−4	5.60×10−4 ± 5.83×10−5
MPS	0.361 ± 0.0812*	1.12×10−3 ± 3.20×10−4	1.55×10−3 ± 3.17×10−4	9.10×10−4 ± 3.22×10−4
MTr	0.430 ± 0.0685	9.12×10−4 ± 1.92×10−4	1.37×10−3 ± 1.87×10−4	6.84×10−4 ± 2.01×10−4

^*P < 0.05 versus CTL (bold type).