title: Impact of scanning density on spectral domain optical coherence tomography assessments in neovascular age-related macular degeneration.
abstract: OBJECTIVE
  To determine the effect of optical coherence tomography (OCT) B-scan density on the qualitative assessment of neovascular age-related macular degeneration (AMD).
  
  
  METHODS
  Data were collected from 59 patients imaged with Topcon 3D OCT-1000 (128 B-scans × 512 A-scans). Custom software was used to generate less dense subsets of scans: 1/16 (eight B-scans), 1/8 (16 B-scans), 1/4 (32 B-scans) and 1/2 (64 B-scans). At each B-scan density, scans were assessed for cystoid spaces, subretinal fluid (SRF), subretinal tissue (SRT) and pigment epithelium detachment (PED). For each sampling density, sensitivity, specificity and predictive values were calculated using the full volume scan (128 B-scans) as the reference standard.
  
  
  RESULTS
  For cystoid spaces, the detection sensitivity was 76.3% at 1/16 density; this rose to 89.5% with a 1/4 density. For SRF, the detection sensitivity was 75.0% at a 1/16 density; this increased to 91.1% with 1/4 density. For PED, even at the lowest sampling density (1/16) the detection sensitivity was 86.4%; this rose to 94.9% at 1/4 density. For SRT, detection sensitivity at a 1/16 density was 64.7% and only rose above 90% with the densest sampling subset (1/2).
  
  
  CONCLUSIONS
  Use of scanning protocols with reduced sampling densities resulted in decreased detection of key features of neovascular AMD; despite this, a sampling density reduced to 1/4 appeared to allow accurate assessment for most features. Current management of neovascular AMD is dependent on qualitative assessment of OCT images; with the recent proliferation of OCT systems, optimization and standardization of scanning protocols may be of value.
authors.affiliation: Doheny Image Reading Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA
authors.forename: Anne E
authors.initials: AE
authors.lastname: Barañano
authors.forename: Pearse A
authors.initials: PA
authors.lastname: Keane
authors.forename: Humberto
authors.initials: H
authors.lastname: Ruiz-Garcia
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Walsh
authors.forename: Srinivas R
authors.initials: SR
authors.lastname: Sadda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008269:Macular Edema / Q000175:diagnosis*; D008297:Male; D010857:Pigment Epithelium of Eye / Q000473:pathology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D058471:Subretinal Fluid; D041623:Tomography, Optical Coherence / Q000379:methods*; D057135:Wet Macular Degeneration / Q000175:diagnosis*