18F-FDG PET/MRI–guided localization of pain generators in chronic neck pain associated with presumed cervical dystonia

Localization of clinically relevant pain generators remains a major diagnostic challenge. MRI frequently demonstrates structural abnormalities that may lack symptomatic correlation, limiting identification of true nociceptive targets. ¹⁸F-FDG PET/MRI enables simultaneous metabolic and anatomic assessment and may help identify clinically actionable pain generators. A 68-year-old man with chronic refractory neck pain underwent ¹⁸F-FDG PET/MRI, which demonstrated focal hypermetabolism within the right obliquus capitis inferior and right longus colli muscles without corresponding structural MRI abnormalities. In conjunction with clinical findings, imaging results supported a presumptive diagnosis of cervical dystonia. Targeted CT- and US-guided lidocaine/triamcinolone injection, followed by botulinum toxin type A injection, was temporally associated with marked symptomatic improvement. ¹⁸F-FDG PET/MRI may help localize metabolically active pain generators not identified on conventional imaging and support hypothesis-driven image-guided procedural targeting in selected patients with unexplained persistent pain.