A study presented at the annual conference of the Radiological Society of North America (RSNA) has shown empirical evidence of the role played by the neck muscles in primary headaches. Improved therapies might result from the results.

The distinct underlying causes of primary headaches are still not fully understood. The most common primary headaches are tension-type headaches and migraines.

"Our imaging approach provides first objective evidence for the very frequent involvement of the neck muscles in primary headaches, such as neck pain in migraine or tension-type headache, using the ability to quantify subtle inflammation within muscles," said Nico Sollmann, M.D., Ph.D., resident in the Department of Diagnostic and Interventional Radiology at University Hospital Ulm, and the Department of Diagnostic and Interventional Neuroradiology at University Hospital Rechts der Isar in Munich, Germany.

Tension-type headaches affect two out of every three adults in the U.S. People with tension-type headaches often feel a tightening in the head and mild to moderate dull pain on both sides of the head.

While these headaches are typically associated with stress and muscle tension, their exact origin is not fully understood.

Migraines are characterised by severe throbbing pain. Migraines generally occur on one side of the head, or the pain is worse on one side. It may also cause nausea, weakness and light sensitivity.

According to the American Migraine Foundation, over 37 million people in the U.S. are affected by migraine, and up to 148 million people worldwide suffer from chronic migraine. Neck pain is commonly associated with primary headaches. However, no objective biomarkers exist for myofascial involvement.

Myofascial pain is associated with inflammation or irritation of muscle or of the connective tissue, known as fascia, that surrounds the muscle.

For the study, Dr Sollmann and colleagues aimed to investigate the involvement of the trapezius muscles in primary headache disorders by quantitative magnetic resonance imaging (MRI) and to explore associations between muscle T2 values and headache and neck pain frequency.

The prospective study included 50 participants, mostly women, ranging in age from 20 to 31 years old. Of the study group, 16 had tension-type headaches, and 12 had tension-type headaches plus migraine episodes.

The groups were matched with 22 healthy controls. All participants underwent a 3D turbo spin-echo MRI. The bilateral trapezius muscles were manually segmented, followed by muscle T2 extraction.