Poster 2: Joint and Clinical Studies

Diego A. Caban-Rivera BS, Curtis L. Johnson PhD, Daniel R. Smith PhD (Emory University), M. Wade Shrader MD (Nemours A.I. duPont Hospital for Children), Stephanie Lee MS (Nemours Children’s Health-Delaware), Ellie Wright BA (Nemours Children’s Health-Delaware), Chris Church MPT (Nemours Children’s Health-Delaware), Faaiza Kazmi MD (Nemours Children’s Health-Delaware), Jason J. Howard MD (Nemours A.I. duPont Hospital for Children)

University of Delaware

Increased muscle stiffness is common in cerebral palsy (CP), but a reliable method of quantification is lacking. Magnetic resonance elastography (MRE) enables simultaneous stiffness measurements across muscles within an anatomic space. The study objective was to measure muscle stiffness in the gastrocnemius-soleus (G-S) complex from children with spastic hemiplegic CP, comparing more affected (MA) to less affected (LA) sides.
Participants underwent an MRE sequence with 80Hz external vibration delivered to each leg by a pneumatic transducer. A nonlinear inversion algorithm produced shear stiffness outputs for the entire G-S complex.
MRE/MRI scans were performed for 6 patients (4F), mean age 10.7 (range 5-17) years. Mean shear stiffness between sides (LA/MA) for gastrocnemius and soleus were not different (3.337 vs 3.4178 kPA, p=0.31; 4.224 vs 4.365 kPA, p=0.26, respectively), while significant differences between volumes were found (67.6 vs 47.1 cm3, p=0.046; 100.2 vs 71.7 cm3, p=0.005). Shear stiffness (LA/MA) was correlated with age for soleus [r=0.86 (p=0.03)/r=0.89 (p=0.02)].
These results suggest that G-S complex muscle belly stiffness is not different between sides in hemiplegic CP, yet soleus for both sides stiffened with age. Future studies are required to determine contributions of the entire muscle-tendon unit to overall stiffness of the gastrocnemius-soleus complex.

Research Area: Muscle