Article
Intraoperative measurement of cortical perfusion using indocyanine-green videoangiography – results of a feasibility study in stroke patients
Intraoperative Messung der kortikalen Perfusion mittels Indocyanin-Grün Video-Angiographie – Ergebnisse einer Studie zur Durchführbarkeit an Schlaganfallpatienten
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Published: | May 8, 2006 |
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Objective: Advanced monitoring strategies of critically hypoperfused brain tissue by different types of local probes require adequate probe placement. Therefore, appropriate intraoperative perfusion measurement would be beneficial to guide probe placement into the cerebral areas of risk. Recently, near-infrared indocyanine-green (ICG) videoangiography was described for the assessment of blood vessel perfusion during neuro-surgical operations. To assess intraoperativel cortical perfusion with high spatial resolution we have adapted this method to quantify hemodynamics in patients with impaired cerebral blood supply due to brain infarction.
Methods: Operative hemicraniectomy due to malignant middle cerebral artery infarction was performed in five patients (3 female, 2 male) with a mean age of 43 years (range: 30 to 57 years). Following the completion of the bone flap removal and dura opening, each patient was given ICG (0.3 mg/kg body weight) systemically via an intravenous bolus injection. A near-infrared light emitted by laser diodes was used to illuminate the operating field and the intravascular fluorescence was recorded using an optical filter-equipped video camera. Flowmaps of cortical perfusion were generated with the aid of IC-CALC 1.0 software by measuring the ratio of rise time, defined as time interval between 20% and 80% of maximum fluorescence intensity, and difference in fluorescence intensity during this time interval.
Results: In all cases excellent visualization of cerebral arteries and brain perfusion was noted. Collateral circulation via leptomeningeal anastomoses could be visualized. Flowmaps were of excellent spatial resolution and showed heterogeneous perfusion within the territory.of the middle cerebral artery.
Conclusions: The method appears to be valuable in detecting relative cortical tissue perfusion precisely and may help surgeons to maintain adequate brain perfusion during vascular surgery or provide for adequate placement of different types of probes to monitor critically hypoperfused cerebral tissue during the postoperative phase.