JCAHPO Imaging 2 — Questions and Answers
Question 1: Which OCT imaging feature is most characteristic of a macular hole?
- Full-thickness retinal defect with elevated edges (Correct answer)
- Subretinal fluid without retinal break
- Hyperreflective dots in the vitreous
- Disruption of the RPE band only
Correct answer: Full-thickness retinal defect with elevated edges
A macular hole appears on OCT as a full-thickness defect through all retinal layers with cuffing (elevated edges) due to fluid accumulation.
Question 2: On fluorescein angiography, a 'blocked fluorescence' pattern is caused by:
- Leakage of dye from abnormal vessels
- Staining of scar tissue
- Preretinal or subretinal material blocking the choroidal signal (Correct answer)
- Choroidal neovascularization
Correct answer: Preretinal or subretinal material blocking the choroidal signal
Blocked fluorescence occurs when blood, pigment, or exudate blocks the normal choroidal fluorescence from reaching the camera.
Question 3: Which imaging modality is considered the gold standard for detecting choroidal tumors and their extent?
- Fundus photography
- B-scan ultrasonography (Correct answer)
- Optical coherence tomography
- Fluorescein angiography
Correct answer: B-scan ultrasonography
B-scan ultrasonography is the gold standard for evaluating choroidal tumors because it penetrates media opacities and reveals internal tumor structure.
Question 4: In optical coherence tomography angiography (OCTA), flow is detected by:
- Fluorescent dye leakage patterns
- Decorrelation of signal between repeated B-scans (Correct answer)
- Reflectivity differences between tissue types
- Phase shift of the laser wavelength
Correct answer: Decorrelation of signal between repeated B-scans
OCTA detects blood flow by measuring the decorrelation (variation) in OCT signal between sequential B-scans caused by moving erythrocytes.
Question 5: A 'geographic atrophy' pattern on fundus autofluorescence (FAF) appears as:
- Hyperautofluorescent ring surrounding the fovea
- Hypoautofluorescent area corresponding to RPE loss (Correct answer)
- Diffuse speckled hyperautofluorescence
- Focal bright spot with surrounding halo
Correct answer: Hypoautofluorescent area corresponding to RPE loss
Geographic atrophy appears as a sharply demarcated hypoautofluorescent area because absent RPE cells cannot produce lipofuscin fluorescence.
Question 6: When performing corneal topography, a 'cone' pattern on axial curvature maps suggests:
- Normal prolate corneal shape
- Keratoconus with inferior steepening (Correct answer)
- Post-LASIK flattening centrally
- Against-the-rule astigmatism
Correct answer: Keratoconus with inferior steepening
Keratoconus typically produces an inferior or paracentral zone of steepening (warm colors) on axial curvature maps representing the conical protrusion.
Question 7: Which artifact in OCT imaging results from patient movement during the scan acquisition?
- Mirror artifact
- Motion artifact appearing as a horizontal band discontinuity (Correct answer)
- Floater shadow artifact
- Specular reflection artifact
Correct answer: Motion artifact appearing as a horizontal band discontinuity
Patient motion during OCT scanning creates horizontal band discontinuities or 'step' artifacts that disrupt the continuity of retinal layers.
JCAHPO Imaging 2
Which OCT imaging feature is most characteristic of a macular hole?