Imaging Flashcards

Which OCT imaging feature is most characteristic of a macular hole?

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.

On fluorescein angiography, a 'blocked fluorescence' pattern is caused by:

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.

Which imaging modality is considered the gold standard for detecting choroidal tumors and their extent?

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.

In optical coherence tomography angiography (OCTA), flow is detected by:

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.

A 'geographic atrophy' pattern on fundus autofluorescence (FAF) appears as:

Answer: Hypoautofluorescent area corresponding to RPE loss

Geographic atrophy appears as a sharply demarcated hypoautofluorescent area because absent RPE cells cannot produce lipofuscin fluorescence.

When performing corneal topography, a 'cone' pattern on axial curvature maps suggests:

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.

Which artifact in OCT imaging results from patient movement during the scan acquisition?

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.