13.1 Manual of PCI - Intravascular imaging: when and which modality?

Intravascular imaging can greatly facilitate planning and performance of PCI. It can be used before PCI for:
1. Assessing left main significance
2. Culprit lesion in ACS
3. Examining angiographically ambiguous lesions
4. Stent failure (in-stent restenosis or stent thrombosis)
5. Determining risk of distal embolization

Intravascular imaging can be used during PCI to:
1. Assess need for lesion preparation
2. Facilitate CTO crossing
3. Select stent landing zone
4. Choose balloon/stent diameter + length
5. Evaluate result after stenting, esp. complex lesions: Left main, Bifurcations, Calcification, etc.
6. Reduce contrast volume (IVUS)

Either OCT or IVUS can be used in most cases to guide PCI. IVUS is preferred for CTO crossing, assessing aorto-ostial lesions and minimizing contrast volume. OCT is preferred when looking for thrombus or dissection and when assessing stent strut apposition.