title: Comparison of indocyanine green angiography and laser speckle contrast imaging for the assessment of vasculature perfusion.
abstract: BACKGROUND
  Assessment of the vasculature is critical for overall success in cranial vascular neurological surgery procedures. Although several methods of monitoring cortical perfusion intraoperatively are available, not all are appropriate or convenient in a surgical environment. Recently, 2 optical methods of care have emerged that are able to obtain high spatial resolution images with easily implemented instrumentation: indocyanine green (ICG) angiography and laser speckle contrast imaging (LSCI).
  
  
  OBJECTIVE
  To evaluate the usefulness of ICG and LSCI in measuring vessel perfusion.
  
  
  METHODS
  An experimental setup was developed that simultaneously collects measurements of ICG fluorescence and LSCI in a rodent model. A 785-nm laser diode was used for both excitation of the ICG dye and the LSCI illumination. A photothrombotic clot model was used to occlude specific vessels within the field of view to enable comparison of the 2 methods for monitoring vessel perfusion.
  
  
  RESULTS
  The induced blood flow change demonstrated that ICG is an excellent method for visualizing the volume and type of vessel at a single point in time; however, it is not always an accurate representation of blood flow. In contrast, LSCI provides a continuous and accurate measurement of blood flow changes without the need of an external contrast agent.
  
  
  CONCLUSIONS
  These 2 methods should be used together to obtain a complete understanding of tissue perfusion.
authors: Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA. eweber@utexas.edu
authors: Erica L
authors: EL
authors: Towle
authors: Lisa M
authors: LM
authors: Richards
authors: S M Shams
authors: SM
authors: Kazmi
authors: Douglas J
authors: DJ
authors: Fox
authors: Andrew K
authors: AK
authors: Dunn
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D003287:Contrast Media; D005451:Fluorescein Angiography; D007208:Indocyanine Green; D007834:Lasers; D016343:Monitoring, Intraoperative; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000502:physiology; D013997:Time Factors; D014656:Vascular Surgical Procedures / Q000379:methods*
chemical_list: D003287:Contrast Media; D007208:Indocyanine Green