Arkiev D'Souza1, Bart Bolsterlee2, Robert D Herbert3. 1. NeuRA, Randwick, NSW, Australia; University of New South Wales, Randwick, NSW, Australia. Electronic address: a.dsouza@neura.edu.au. 2. NeuRA, Randwick, NSW, Australia; University of New South Wales, Randwick, NSW, Australia. Electronic address: b.bolsterlee@neura.edu.au. 3. NeuRA, Randwick, NSW, Australia; University of New South Wales, Randwick, NSW, Australia. Electronic address: r.herbert@neura.edu.au.
Abstract
People who have had a stroke often develop ankle contractures which may be caused by changes in architecture of calf muscles. Anatomically constrained diffusion tensor imaging has recently been used to make three-dimensional, whole-muscle measurements of muscle architecture. Here, we compared the architecture of the medial gastrocnemius muscle in the paretic and non-paretic sides of people who have had a hemiparetic stroke and control participants using novel imaging techniques. METHODS: MRI techniques (diffusion tensor imaging and mDixon imaging) were used to obtain muscle volume, fascicle length, pennation angle, physiological cross-sectional area and curvature in 14 stroke patients (mean age 60 SD 13 years) and 18 control participants (mean age 66 SD 12 years). FINDINGS: On average, the ankle on the paretic side had 11° (95% confidence interval 8 to 13°) less dorsiflexion range than on the non-paretic side, and 6° (1 to 13°) less dorsiflexion range than ankles of control participants. The medial gastrocnemius muscles on the paretic side were, on average, 15% (35.2 cm3, 95% confidence interval 5.2 to 65.2 cm3) smaller in volume than the muscles on the non-paretic side, and 16% (36.9 cm3, 95% confidence interval 3.1 to 70.6 cm3) smaller than in control participants. No statistically significant differences between paretic, non-paretic and control muscles were detected for fascicle length, pennation angle, physiological cross-sectional area or curvature. CONCLUSIONS: People with hemiparetic stroke and reduced range of motion have, on average, a smaller medial gastrocnemius muscle on the paretic side than on the non-paretic side. Other muscle architectural parameters appear unchanged.
People who have had a stroke often develop ankle contractures which may be caused by changes in architecture of calf muscles. Anatomically constrained diffusion tensor imaging has recently been used to make three-dimensional, whole-muscle measurements of muscle architecture. Here, we compared the architecture of the medial gastrocnemius muscle in the paretic and non-paretic sides of people who have had a hemiparetic stroke and control participants using novel imaging techniques. METHODS: MRI techniques (diffusion tensor imaging and mDixon imaging) were used to obtain muscle volume, fascicle length, pennation angle, physiological cross-sectional area and curvature in 14 strokepatients (mean age 60 SD 13 years) and 18 control participants (mean age 66 SD 12 years). FINDINGS: On average, the ankle on the paretic side had 11° (95% confidence interval 8 to 13°) less dorsiflexion range than on the non-paretic side, and 6° (1 to 13°) less dorsiflexion range than ankles of control participants. The medial gastrocnemius muscles on the paretic side were, on average, 15% (35.2 cm3, 95% confidence interval 5.2 to 65.2 cm3) smaller in volume than the muscles on the non-paretic side, and 16% (36.9 cm3, 95% confidence interval 3.1 to 70.6 cm3) smaller than in control participants. No statistically significant differences between paretic, non-paretic and control muscles were detected for fascicle length, pennation angle, physiological cross-sectional area or curvature. CONCLUSIONS:People with hemiparetic stroke and reduced range of motion have, on average, a smaller medial gastrocnemius muscle on the paretic side than on the non-paretic side. Other muscle architectural parameters appear unchanged.