title: Protoporphyrin-IX fluorescence guided surgical resection in high-grade gliomas: The potential impact of human colour perception.
abstract: BACKGROUND
  Protoporphyrin-IX (Pp-IX) fluorescence had been used frequently in recent years to guide microsurgical resection of high-grade gliomas (HGG), particularly following the publication of a randomized controlled trial demonstrating its advantages. However, Pp-IX fluorescence is dependent upon the surgeons' eyes' perception of red fluorescent colour. This study was designed to evaluate human eye fluorescence perception and establish a fluorescence scale.
  
  
  METHODS
  20 of 108 pre-recorded images from intraoperative fluorescence of HGG were used to construct an 8-panel visual analogue fluorescence scale. The scale was validated by testing 56 participants with normal colour vision and three red-green colour-blind participants. For intra-rater agreement ten participants were tested twice and for inter-observer reliability the whole cohort were tested.
  
  
  RESULTS
  The intra- and inter-observer reliability of the scale in normal colour vision participants was excellent. The scale was less reliable in the violet-blue panels of the scale. Colour-blind participants were not able to distinguish between red fluorescence and blue-violet colours.
  
  
  CONCLUSIONS
  The 8-panel fluorescence scale is valid in differentiating red, pink and blue colours in a fluorescence surgical field among participants with normal colour perception and potentially useful to standardize fluorescence-guided surgery. However, colourblind surgeons should not use fluorescence-guided surgery.
authors.affiliation: Linkopings University, Scotland, UK.
authors.forename: Max
authors.initials: M
authors.lastname: Petterssen
authors.affiliation: Lothian Radiology Training Programme, Scotland, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Eljamel
authors.affiliation: Department of Neurosurgery, The University of Dundee, UK(1). Electronic address: sameljamel@doctors.net.uk.
authors.forename: Sam
authors.initials: S
authors.lastname: Eljamel
mesh_terms: D001932:Brain Neoplasms / Q000473:pathology* / Q000601:surgery; D003118:Color Perception / Q000502:physiology*; D005260:Female; D005456:Fluorescent Dyes; D005910:Glioma / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008856:Microscopy, Fluorescence / Q000379:methods*; D015588:Observer Variation; D017319:Photosensitizing Agents; D011524:Protoporphyrins; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D017319:Photosensitizing Agents; D011524:Protoporphyrins; C028025:protoporphyrin IX
keywords: Colour-perception; Colourblind; Fluorescence-scale; Glioblastoma; Surgical resection