Evaluation of the Relationship Between Ultrasonographic Muscle Morphology, Functional Properties, and Clinical Parameters in Children With Spastic Cerebral Palsy

This prospective, cross-sectional observational study aims to explore the relationship between ultrasonographically assessed muscle morphology, functional muscle characteristics, and standardized clinical parameters in ambulatory children diagnosed with spastic cerebral palsy (CP). The research seeks to enhance the understanding of muscle structure-function relationships in this population, with the broader goal of contributing to personalized rehabilitation strategies and clinical decision-making.

Cerebral palsy is a non-progressive neurodevelopmental disorder resulting from brain injury or maldevelopment during the prenatal, perinatal, or early postnatal period. Spastic cerebral palsy is the most common subtype, characterized by upper motor neuron lesions that lead to increased muscle tone, spasticity, and movement dysfunction. These neuromuscular alterations often result in secondary changes in muscle morphology, such as increased stiffness, reduced muscle volume, shortened fascicle length, altered fiber orientation, and impaired microcirculation. Understanding how these changes relate to functional limitations remains an important goal in pediatric rehabilitation research.

In this study, both structural and functional properties of skeletal muscles are planned to be assessed using a combination of high-resolution ultrasound techniques. The targeted muscles for assessment include one lower limb and one upper limb muscle: the medial gastrocnemius and the brachialis. These muscles were selected due to their relevance in gross motor and upper limb function in children with spastic CP.

The ultrasonographic parameters planned for evaluation include muscle thickness (MT), fascicle length (FL), pennation angle (PA), cross-sectional area (CSA), and echo intensity (EI). Additionally, muscle stiffness will be estimated through shear wave elastography (SWE), and vascularity will be evaluated using superb microvascular imaging (SMI) or a similar non-contrast-enhanced microvascular ultrasound technique. These advanced imaging modalities allow for the assessment of tissue elasticity and intramuscular blood flow, serving as potential surrogate markers of muscle quality and pathology.

Measurements will be acquired under standardized conditions, with the muscles in a relaxed state and proper anatomical alignment. Multiple images and repeated measurements will be obtained to ensure consistency. Longitudinal and transverse imaging planes will be used depending on the parameter being evaluated. The ultrasonographic protocol is designed to minimize operator-dependent variability and to ensure reproducibility across participants.