Which statement best distinguishes IVUS and OCT imaging characteristics?

Which statement best distinguishes IVUS and OCT imaging characteristics?

• A. OCT penetrates deeper than IVUS and doesn't require blood clearance.
• B. IVUS uses ultrasound to image deeper tissues; OCT uses near-infrared light with higher resolution but requires blood clearance.
• C. IVUS provides high-resolution lumen details and thin-cap imaging.
• D. OCT cannot image lumen.

Answer: (B)

The key difference is how each modality images the vessel and what each one emphasizes. IVUS uses ultrasound, which can penetrate deeper into the vessel wall and plaque, giving a good sense of overall plaque burden and wall morphology even behind the lumen. OCT uses near-infrared light, which provides much higher axial resolution so you can see fine surface details and thin-cap features, but its light can’t go as deep, so image depth is limited. Because blood scatters and absorbs light, OCT requires clearing the field with a flush (usually contrast or saline) to obtain a clear image. IVUS, on the other hand, can image through blood without needing such clearance. That combination—IVUS with deeper penetration via ultrasound and OCT with higher resolution but the need for blood clearance—best distinguishes the two.

The key difference is how each modality images the vessel and what each one emphasizes. IVUS uses ultrasound, which can penetrate deeper into the vessel wall and plaque, giving a good sense of overall plaque burden and wall morphology even behind the lumen. OCT uses near-infrared light, which provides much higher axial resolution so you can see fine surface details and thin-cap features, but its light can’t go as deep, so image depth is limited. Because blood scatters and absorbs light, OCT requires clearing the field with a flush (usually contrast or saline) to obtain a clear image. IVUS, on the other hand, can image through blood without needing such clearance.

That combination—IVUS with deeper penetration via ultrasound and OCT with higher resolution but the need for blood clearance—best distinguishes the two.