Diffusion Tensor Imaging of the Normal Foot at 3 T

OBJECTIVE: The objective of this study was to establish normative diffusion tensor imaging (DTI) eigenvalues (λ1,λ2,λ3), apparent diffusion coefficient, and fractional anisotropy in asymptomatic foot muscles. METHODS: Ten healthy adults (mean [SD], 25.9 [4.3] years) were examined using a 3-T magnetic resonance imaging scanner. Diffusion tensor imaging indices were evaluated in 5 muscles in the foot: quadratus plantae, abductor hallucis, flexor hallucis brevis, flexor digitorum brevis, and abductor digiti minimi. Signal-to-noise ratio was also measured for each muscle. RESULTS: In the various foot muscles, λ1 ranged from 1.88 × 10 to 2.14 × 10 mm/s, λ2 ranged from 1.39 × 10 to 1.48 × 10 mm/s, and λ3 ranged from 0.91 × 10 to 1.27 × 10 mm/s; apparent diffusion coefficient ranged from 1.48 × 10 to 1.55 × 10 mm/s; and fractional anisotropy ranged from 0.21 to 0.40. Statistical differences were seen in some eigenvalues between muscle pairs. Mean signal-to-noise ranged from 47.5 to 69.1 in the various muscles examined. CONCLUSIONS: Assessment of anisotropy of water diffusion in foot muscles was feasible using DTI. The measured DTI metrics in the foot were similar to those in calf and thigh skeletal muscles.