title: Blood flow velocity changes in carotid and vertebral arteries with stellate ganglion block: measurement by magnetic resonance imaging using a direct bolus tracking method.
abstract: OBJECTIVE
  Stellate ganglion block (SGB) leads to vasodilation of the head and neck, as a result of a regional sympathetic blockade. However, in such cases, controversy remains concerning changes in cerebral and extracerebral blood flow in the head. We estimated the effect of SGB on blood flow in the head by measuring the blood flow velocity in cervical vessels, using magnetic resonance imaging and the direct bolus tracking method. This noninvasive method is free from potential artifacts of bones and other connective tissues.
  
  
  METHODS
  Seven adult patients with acute or chronic pain in the head or neck underwent SGBs, using an anterior paratracheal approach with 6-8 mL of 1% mepivacaine (3 right and 4 left SGBs). Blood flow velocity in common carotid and vertebral arteries (CCA and VA) was measured simultaneously before and after SGB, using the direct bolus tracking method.
  
  
  RESULTS
  On the side of SGB, blood flow velocity in CCA significantly increased (P < .002), whereas velocity in VA was unchanged after SGB. On the side contralateral to the SGB, significant changes in blood flow velocity in CCA and VA were never observed.
  
  
  CONCLUSIONS
  Blood from the VA flows primarily to cerebral vessels, whereas that from CCA goes to both cerebral and extracerebral vessels. Given the presumed differences in blood flow distribution through the VA and CCA, we assume that the observed CCA blood flow increases, ipsilateral to the SGB, primarily as a result of vasodilation of extracerebral vessels and independent of changes in brain blood flow.
authors.affiliation: Department of Anesthesiology, School of Medicine, Fukuoka University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nitahara
authors.forename: K
authors.initials: K
authors.lastname: Dan
mesh_terms: D000208:Acute Disease; D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage; D016477:Artifacts; D001340:Autonomic Nerve Block; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000098:blood supply; D017536:Carotid Artery, Common / Q000187:drug effects / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D002908:Chronic Disease; D005260:Female; D006257:Head / Q000098:blood supply; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008619:Mepivacaine / Q000008:administration & dosage; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis; D012039:Regional Blood Flow / Q000187:drug effects; D013233:Stellate Ganglion; D014664:Vasodilation; D014711:Vertebral Artery / Q000187:drug effects / Q000502:physiology*
chemical_list: D000779:Anesthetics, Local; D008619:Mepivacaine