title: Multimodal Imaging of Cotton Wool Spots in Branch Retinal Vein Occlusion.
abstract: OBJECTIVE
  To describe and follow cotton wool spots (CWS) in branch retinal vein occlusion (BRVO) using multimodal imaging.
  
  
  METHODS
  In this prospective cohort study including 24 patients with new-onset BRVO, CWS were described and analyzed in color fundus photography (CF), spectral domain optical coherence tomography (SD-OCT), infrared (IR) and fluorescein angiography (FA) every 3 months for 3 years. The CWS area on SD-OCT and CF was evaluated using OCT-Tool-Kit software: CWS were marked in each single OCT B-scan and the software calculated the area by interpolation.
  
  
  RESULTS
  29 central CWS lesions were found. 100% of these CWS were visible on SD-OCT, 100% on FA and 86.2% on IR imaging, but only 65.5% on CF imaging. CWS were visible for 12.4 ± 7.5 months on SD-OCT, for 4.4 ± 3 months and 4.3 ± 3.4 months on CF and on IR, respectively, and for 17.5 ± 7.1 months on FA. The evaluated CWS area on SD-OCT was larger than on CF (0.26 ± 0.17 mm(2) vs. 0.13 ± 0.1 mm(2), p < 0.0001). The CWS area on SD-OCT and surrounding pathology such as intraretinal cysts, avascular zones and intraretinal hemorrhage were predictive for how long CWS remained visible (r(2) = 0.497, p < 0.002).
  
  
  CONCLUSIONS
  The lifetime and presentation of CWS in BRVO seem comparable to other diseases. SD-OCT shows a higher sensitivity for detecting CWS compared to CF. The duration of visibility of CWS varies among different image modalities and depends on the surrounding pathology and the CWS size.
authors.affiliation: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
authors.forename: Marion R
authors.initials: MR
authors.lastname: Munk
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Matt
authors.forename: Magdalena
authors.initials: M
authors.lastname: Baratsits
authors.forename: Roman
authors.initials: R
authors.lastname: Dunavoelgyi
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Huf
authors.forename: Alessio
authors.initials: A
authors.lastname: Montuoro
authors.forename: Wolf
authors.initials: W
authors.lastname: Buehl
authors.forename: Ursula
authors.initials: U
authors.lastname: Schmidt-Erfurth
authors.forename: Stefan
authors.initials: S
authors.lastname: Sacu
mesh_terms: D000368:Aged; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D010781:Photography / Q000379:methods; D011446:Prospective Studies; D012166:Retinal Hemorrhage / Q000473:pathology; D012170:Retinal Vein Occlusion / Q000175:diagnosis* / Q000473:pathology; D041623:Tomography, Optical Coherence / Q000379:methods