New research shows for the first time how physiological mechanisms causing chronic soft tissue pain like tennis elbow can be studied with the help of PET scans that “light up” in response to pain receptors.
Researchers from Uppsala University in Sweden documented how the activation of pain receptors is visibly apparent on PET scans in the arms of patients with tennis elbow. This soft tissue pain condition occurs when the tendons of the elbow become inflamed after overuse. Such overuse injuries are an extremely common source of chronic pain in the US, but because they do not involve bone, are often overlooked. Scientists are still attempting to find reliable ways to pinpoint and diagnosis the underlying causes of soft tissue injuries.
This latest study from Uppsala University brings us a step closer to understanding the mechanisms behind soft tissue injuries. Researchers studied PET scans of ten patients with chronic tennis elbow. PET is an imaging technique that generates a three-dimensional picture of a functional process in the body. The researchers then inject chemical compounds called tracers, which bind to specific cells and light up on PET scans to demonstrate changes within those cells. In this study, the researchers injected patients with a radioactive tracer that binds to receptor called NK-1 which is involved in pain processing. The radioactive tracer causes this receptor to light up on PET scans and visually demonstrate areas of heightened pain processing.
The researchers found that the painful arm was significantly brighter on PET scans compared to the non-painful arm, indicating a greater presence in NK-1 receptors. This shows for the first time that in patients with chronic soft tissue pain, receptors involved in pain processing remain activated well after the initial injury.
It’s unlikely that doctors will use PET scans anytime soon for diagnosis of tennis elbow due to costs, but the findings open the way for future methods of tracking tissue damage.
Svärdsudd K, Appel L, Engler H, Aarnio M, et al. PET-Scan Shows Peripherally Increased Neurokinin 1 Receptor Availability in Chronic Tennis Elbow: Visualizing Neurogenic Inflammation? PLoS ONE E 8(10): e75859,; DOI: 10.1371/journal.pone.0075859.
Paddock, Catharine. “Tennis elbow pain lights up in PET scans.” Medical News Today. MediLexicon, Intl., 30 Oct. 2013. Web.
31 Oct. 2013. http://www.medicalnewstoday.com/articles/268102.