Botulinum toxin within the muscle – MRI follow up in children with spastic cerebral palsy supports neurogenic atrophy in healthy muscle one year after a single injection of botulinum toxin

Botulinum toxin is widely used as a therapeutic option to reduce (multi-) focal muscle hypertension as well as for cosmetic indications. Recommendations on reinjection intervals (3-12months) are based on clinical observation and basic science research using animal models. Morphologic long-term alterations following a single injection of botulinum toxin are scarce. With the development of short tau inversion recovery (STIR) sequences Magnetic resonance imaging (MRI) is able to detect neurogenic muscle atrophy over the course of time. The aim of this study was to investigate the neurogenic atrophy induced by a single injection of botulinum toxin in healthy adult muscle and the induced atrophy in primarily altered spastic muscle in children with cerebral palsy (CP).