Which intravascular imaging modality offers the highest resolution but often requires clearing blood from the field?

Which intravascular imaging modality offers the highest resolution but often requires clearing blood from the field?

• A. OCT provides higher resolution and vessel wall imaging, while IVUS offers deeper penetration.
• B. IVUS provides deeper penetration and vessel wall imaging, while OCT offers higher resolution but requires blood clearance.
• C. OCT uses radiation.
• D. Intravascular imaging modalities include IVUS and OCT; OCT provides deeper penetration.

Answer: (B)

The key idea is the trade-off between resolution and how deeply the modality can image. Optical coherence tomography (OCT) gives much higher spatial resolution than intravascular ultrasound (IVUS), allowing detailed views of the lumen and thin vessel-wall layers. However, because OCT uses light, blood strongly scatters and absorbs it, so the imaging field must be cleared—usually by flushing saline or using a temporary occlusion—to obtain a clear image. IVUS, on the other hand, penetrates deeper into the vessel wall, but with lower resolution. So the statement that IVUS provides deeper penetration and vessel wall imaging, while OCT offers higher resolution but requires blood clearance, best captures these differences. The other options are inaccurate: OCT does not use ionizing radiation, and OCT does not have deeper penetration than IVUS.

The key idea is the trade-off between resolution and how deeply the modality can image. Optical coherence tomography (OCT) gives much higher spatial resolution than intravascular ultrasound (IVUS), allowing detailed views of the lumen and thin vessel-wall layers. However, because OCT uses light, blood strongly scatters and absorbs it, so the imaging field must be cleared—usually by flushing saline or using a temporary occlusion—to obtain a clear image. IVUS, on the other hand, penetrates deeper into the vessel wall, but with lower resolution. So the statement that IVUS provides deeper penetration and vessel wall imaging, while OCT offers higher resolution but requires blood clearance, best captures these differences. The other options are inaccurate: OCT does not use ionizing radiation, and OCT does not have deeper penetration than IVUS.