title: Cerebrovascular reacivity assessment in patients with carotid artery disease: a combined TCD and NIRS study.
abstract: OBJECTIVE
  Transcranial Doppler (TCD) and near-infrared spectroscopy (NIRS) are two noninvasive diagnostic tools that have been shown to evaluate cerebral vasomotor reactivity by measuring changes in mean cerebral blood flow velocities (MCBFV) of proximal intracranial arteries and absolute brain-tissue oxygen-saturation (TOS) in microcirculation, respectively, during hemodynamic challenge. We evaluated the potential correlation between TCD and NIRS measurements of vasomotor reactivity (VMR) in patients with carotid artery disease (CARAD).
  
  
  METHODS
  Consecutive patients (n = 24) with CARAD underwent simultaneously TCD and NIRS examinations during voluntary breath-holding (BH). MCBFV and TOS values were recorded at baseline (BAS) and at the end of BH, while BH duration (DBH) was documented. VMR was quantified by means of TCD-BHI (Breath-holding Index: [MCBFV(BH) - MCBFV(BAS)]× 100/MCBFV(BAS)/DBH) and NIRS-BHI ([TOS(BH) - TOS(BAS)]× 100/ TOS(BAS)/DBH).
  
  
  RESULTS
  TCD-BHI correlated positively with NIRS-BHI in the affected side (r = .538, P = .007). A stronger correlation between TCD-BHI and NIRS-BHI was documented in the nonaffected side (r = .768, P< .001). After adjusting for demographic characteristics, stroke risk factors and symptomatic status NIRS-BHI was linearly and independently associated with TCD-BHI both in the affected (β:+ .813, P = .001) and unaffected (β:+ .823, P < .001) side.
  
  
  CONCLUSIONS
  Circulatory assessment of VMR in proximal cerebral vessels by TCD correlates positively to functional measurements of VMR in microcirculation by NIRS in CARAD patients.
authors: Vascular Unit, Third Department of Surgery, School of Medicine, University of Athens, Athens, Greece.
authors: Spyros N
authors: SN
authors: Vasdekis
authors: Georgios
authors: G
authors: Tsivgoulis
authors: Dimitrios
authors: D
authors: Athanasiadis
authors: Athina
authors: A
authors: Andrikopoulou
authors: Konstantinos
authors: K
authors: Voumvourakis
authors: Andreas M
authors: AM
authors: Lazaris
authors: Elefterios
authors: E
authors: Stamboulis
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*; D014666:Vasomotor System / Q000000981:diagnostic imaging / Q000503:physiopathology*
chemical_list: D010100:Oxygen