疼痛的神經影像學標記

Neuroimaging Biomarkers for Pain

疼痛是許多疾病中最令人痛苦的症狀，其帶給病患的折磨常超過疾病本身對身體的直接損傷。慢性疼痛依其發生原因可分為三類：（1）因周邊或中樞神經系統受損而產生的神經病變痛（neuropathic pain），（2）因身體組織受到外傷或疾病損傷而產生的傷害感受性疼痛（nociceptive pain），以及（3）因周邊或中樞神經系統對痛覺刺激變得異常敏感，而產生的傷害可塑性疼痛（nociplastic pain）。傳統痛覺理論認為，疼痛是由於神經或組織損傷後，痛覺末梢的過敏反應所導致，然而大腦的疼痛神經迴路發生病態變化，亦可能促使疼痛產生和持續。腦影像技術，可以提供一個非侵入性的方式，來評估慢性疼痛對大腦的影響，有助於了解腦部處理疼痛的結構及功能網路，並有潛力當作生物指標，來監測藥物及非藥物療法的效果，以改善疼痛病患的處置。

Pain is usually the most excruciating symptom in many diseases. Chronic pain may be divided into three categories: (1) neuropathic pain, which is caused by lesions in the peripheral or central nervous system, (2) nociceptive pain, which is caused by inflammation or damage of body tissues, and (3) nociplastic pain, which is caused by augmented sensory and pain processing in the central nervous system. Conventional theories attribute pain to hypersensitivity of peripheral nociceptive terminals after nerve or tissue injury. However, maladaptive plasticity of the pain circuitry in the brain due to long-term nociceptive input may also facilitate the development and persistence of pain. Brain imaging techniques provide a noninvasive way to assess the influences of chronic pain on the brain, facilitate the identification of structural and functional pain-processing networks in the brain, and have become promising biomarkers to evaluate the therapeutic effects of drug and non-drug therapy to improve the management of patients with chronic pain.