Imaging breakthroughs show how spinal cord injury affects the entire central nervous system

According to a new study published in the Journal of Nuclear Medicine, new pet tracers can provide insight into how spinal cord injuries affect not only the spinal cord but also the brain. By identifying synaptic losses, the PET approach provides molecularly unique and complementary information to other structural imaging methods, providing promising objective metrics for evaluating novel therapeutic agents for spinal cord injury.

According to the National Center for Spinal Cord Injury Statistics, the annual incidence of traumatic spinal cord injuries is approximately 54 cases per million people, with approximately 308,600 people living with spinal cord injuries. Clinical outcomes vary depending on the severity and location of the injury, potentially leading to partial or complete loss of sensory or motor function below the level of injury. Current clinical spinal cord injury diagnosis assesses spinal integrity but relies on anatomical techniques such as x-rays and CT, where physiological and pathological information is limited.

Quantitative and non-invasive imaging methods for neural network changes after spinal cord injury are urgently needed. By providing a non-invasive quantitative method for visualizing and quantifying synaptic loss throughout the central nervous system, SV2A PET could become an essential tool for assessing and monitoring the progression of spinal cord injury.

Dr. Jason Kai, Associate Professor of Radiology and Biomedical Imaging and Pharmacology, Yale School of Medicine, New Haven, Connecticut

The researchers used the newly developed 18F-labeled SV2A radiotraser (18F) Synvest-1 to assess changes in synaptic density in a rat model of T7 contusion. Nine rats with T7 spinal cord injuries and seven sham controls were imaged on day 1 (18F) Synvest-1 PET and on days 11 after injury from days 9 to 11. Imaging findings of the site of injury and brain were compared with ex vivo diffusion tensor imaging (DTI) and molecular biological analysis.

(18F) Synvest-1 PET effectively identified synaptic loss in the Contuse-sized rat model. Intake at the epicenter of the spinal cord injury was found to be reduced by 52% from day 1 and 58% and 52% from day 11 to 11 after injury, respectively, compared to sham control rats. Intake of 18F-Sinvest-1 in the amygdala and cerebellum was also low in spinal cord-injured rats, and ex vivo DTI analysis revealed fibrous damage to the internal capsule and somatosensory cortex.

“Our work can revolutionize the way spinal cord injuries are diagnosed and monitored in clinics. CAI. We say that SV2APET can be used to objectively and quantitatively assess more accurate and personalized treatment strategies for spinal cord injuries patients.”