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FLOW 800 Allows Visualization of Hemodynamic Changes After Extracranial-to-Intracranial Bypass Surgery but Not Assessment of Quantitative Perfusion or Flow

Prinz, Vincent MD*; Hecht, Nils MD*; Kato, Naoki MD; Vajkoczy, Peter MD

doi: 10.1227/NEU.0000000000000277
Technique Assessment

BACKGROUND: FLOW 800 delivers a color-coded map for snapshot visualization of the temporal distribution dynamics after indocyanine green angiography with post hoc calculation of FLOW 800-specific hemodynamic parameters. However, the value of these parameters regarding quantitative flow assessment remains unclear.

OBJECTIVE: To determine the value of FLOW 800-specific hemodynamic parameters in neurosurgical patients that permit assessment of hemodynamic changes within the microcirculation and macrocirculation.

METHODS: FLOW 800 was performed in 25 patients undergoing superficial temporal artery to middle cerebral artery bypass grafting and in 5 patients undergoing high- or intermediate-flow bypass grafting. The time to half-maximum fluorescence (t1/2max) and the cerebral blood flow index were calculated in the recipient vessel (macrocirculation) and the cortical territory (microcirculation) surrounding the anastomosis. For further evaluation, FLOW 800-specific hemodynamic parameters were compared with cortical laser speckle imaging and quantitative Doppler flow within the graft.

RESULTS: FLOW 800 provided color-coded information on the temporospatial distribution dynamics of the dye with excellent assessment of bypass patency. In the recipient vessel and in the cortical territory surrounding the anastomosis, FLOW 800 detected hemodynamic changes after superficial temporal artery to middle cerebral artery bypass grafting in terms of a significant decrease in t1/2max and increase in cerebral blood flow index. Interestingly, comparison of t1/2max with semiquantitative laser speckle imaging-specific cortical perfusion within the microcirculation demonstrated poor agreement, and neither t1/2max nor the cerebral blood flow index within the graft correlated with quantitative graft flow assessed by Doppler.

CONCLUSION: FLOW 800 may detect procedure-related hemodynamic changes within the microcirculation and macrocirculation but should not be used as a stand-alone tool for quantitative flow assessment.

ABBREVIATIONS: AI, arbitrary intensity

CBF, cerebral blood flow

CBFi, cerebral blood flow index

ICG, indocyanine green

ICG-A, indocyanine green angiography

H/IFBP, high-/intermediate-flow bypass

LSI, laser speckle imaging

ROI, region of interest

STA-MCA, superficial temporal artery to middle cerebral artery

Department of Neurosurgery and Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany

Correspondence: Peter Vajkoczy, MD, Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. E-mail:

* These authors have contributed equally to this article.

Received August 12, 2013

Accepted December 10, 2013

© 2014 by Lippincott Williams & Wilkins, Inc.
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