title: Age-related macular degeneration: choroidal ischaemia?
abstract: OBJECTIVE
  Our aim is to use ultrasound to non-invasively detect differences in choroidal microarchitecture possibly related to ischaemia among normal eyes and those with wet and dry age-related macular degeneration (AMD).
  
  
  METHODS
  Prospective case series of subjects with dry AMD, wet AMD and age-matched controls.
  
  
  METHODS
  Digitised 20 MHz B-scan radiofrequency ultrasound data of the region of the macula were segmented to extract the signal from the retina and choroid. This signal was processed by a wavelet transform, and statistical modelling was applied to the wavelet coefficients to examine differences among dry, wet and non-AMD eyes. Receiver operating characteristic (ROC) analysis was used to evaluate a multivariate classifier.
  
  
  RESULTS
  In the 69 eyes of 52 patients, 18 did not have AMD, 23 had dry AMD and 28 had wet AMD. Multivariate models showed statistically significant differences between groups. Multiclass ROC analysis of the best model showed an excellent volume-under-curve of 0.892±0.17. The classifier is consistent with ischaemia in dry AMD.
  
  
  CONCLUSIONS
  Wavelet augmented ultrasound is sensitive to the organisational elements of choroidal microarchitecture relating to scatter and fluid tissue boundaries such as seen in ischaemia and inflammation, allowing statistically significant differentiation of dry, wet and non-AMD eyes. This study further supports the association of ischaemia with dry AMD and provides a rationale for treating dry AMD with pharmacological agents to increase choroidal perfusion. ClinicalTrials.gov registration: NCT00277784.
authors.affiliation: Department of Ophthalmology, Columbia University Medical Center, New York, New York 10032, USA. djceye@gmail.com
authors.forename: D Jackson
authors.initials: DJ
authors.lastname: Coleman
authors.forename: Ronald H
authors.initials: RH
authors.lastname: Silverman
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Rondeau
authors.forename: Harriet O
authors.initials: HO
authors.lastname: Lloyd
authors.forename: Aziz A
authors.initials: AA
authors.lastname: Khanifar
authors.forename: R V Paul
authors.initials: RV
authors.lastname: Chan
mesh_terms: D002829:Choroid / Q000098:blood supply*; D004396:Coloring Agents; D005451:Fluorescein Angiography; D057092:Geographic Atrophy / Q000145:classification / Q000000981:diagnostic imaging*; D006801:Humans; D007208:Indocyanine Green; D007511:Ischemia / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D012372:ROC Curve; D041623:Tomography, Optical Coherence; D014463:Ultrasonography; D057135:Wet Macular Degeneration / Q000145:classification / Q000000981:diagnostic imaging*
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green
keywords: Choroid; Degeneration; Imaging; Macula; Treatment Medical