title: Neural correlates of chronic low back pain measured by arterial spin labeling.
abstract: BACKGROUND
  The varying nature of chronic pain (CP) is difficult to correlate to neural activity using typical functional magnetic resonance imaging methods. Arterial spin labeling is a perfusion-based imaging technique allowing the absolute quantification of regional cerebral blood flow, which is a surrogate measure of neuronal activity.
  
  
  METHODS
  Subjects with chronic low back and radicular pain and matched healthy normal subjects, undergoing identical procedures, participated in three sessions: a characterization and training session and two arterial spin labeling sessions. In the first imaging session, CP (if any) was exacerbated using clinical maneuvers; in the second session, noxious heat was applied to the affected leg dermatome, the intensity of which was matched to the pain intensity level of the CP exacerbations for each back pain subject.
  
  
  RESULTS
  The clinically significant worsening of ongoing CP (≤ 30%, n = 16) was associated with significant regional blood flow increases (6-10 mm/100 g of tissue/min, P less than 0.01) within brain regions known to activate with experimental pain (somatosensory, prefrontal, and insular cortices) and in other structures observed less frequently in experimental pain studies, such as the superior parietal lobule (part of the dorsal attention network). This effect is specific to changes in ongoing CP as it is observed during worsening CP, but it is not observed after thermal pain application, or in matched, pain-free healthy controls.
  
  
  CONCLUSIONS
  Study findings demonstrate the use of arterial spin labeling to investigate the neural processing of CP, and these findings are a step forward in the quest for objective biomarkers of the chronic pain experience.
authors: Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA. awasan@partners.org
authors: Ajay D
authors: AD
authors: Wasan
authors: Marco L
authors: ML
authors: Loggia
authors: Li Q
authors: LQ
authors: Chen
authors: Vitaly
authors: V
authors: Napadow
authors: Jian
authors: J
authors: Kong
authors: Randy L
authors: RL
authors: Gollub
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology* / Q000523:psychology; D008297:Male; D008875:Middle Aged; D013113:Spin Labels
chemical_list: D013113:Spin Labels