IVUS, OCT & FFR

Introduction to Intravascular Imaging and Physiology

Modern cardiology uses advanced tools to diagnose and treat heart conditions with high precision. IVUS (Intravascular Ultrasound), OCT (Optical Coherence Tomography), and FFR (Fractional Flow Reserve) are three powerful technologies. These help cardiologists look inside arteries, assess blockages, and decide the best treatment options.

What Is IVUS (Intravascular Ultrasound)?

IVUS is a catheter-based imaging technique. It uses sound waves to create detailed images of the inside of blood vessels.

How IVUS Works

A tiny ultrasound probe is attached to a catheter. It’s inserted into the artery and moved to the area of interest. The device then sends out sound waves that bounce off artery walls. These echoes create real-time cross-sectional images.

Benefits of IVUS

Shows the depth and size of plaque
Helps plan precise stent placement
Assists in identifying hidden artery diseases
Guides treatment in complex cases

IVUS is extremely helpful when angiography images are unclear.

What Is OCT (Optical Coherence Tomography)?

OCT is another catheter-based imaging tool. Unlike IVUS, it uses light waves instead of sound. It offers much higher resolution and finer detail of the vessel wall.

How OCT Works

A laser-based probe is threaded through the artery. As it moves, it captures high-definition images of the artery’s inner lining.

Benefits of OCT

Visualizes thin plaques and small vessel injuries
Detects stent malapposition or incomplete deployment
Ideal for post-stenting evaluation
Provides better detail than IVUS in some cases

OCT is best used when high-resolution imaging is needed.

What Is FFR (Fractional Flow Reserve)?

FFR is a technique that measures pressure differences across a coronary artery blockage. It tells doctors how much a blockage affects blood flow to the heart.

How FFR Works

A special pressure wire is inserted into the artery. Medication is given to dilate the vessels. The wire then records pressure before and after the narrowing. The FFR value indicates if the blockage is significant.

FFR Values

>0.80: Likely no need for stenting
<0.80: Indicates reduced blood flow; stenting or angioplasty may help

Benefits of FFR

Confirms whether a blockage is causing symptoms
Prevents unnecessary stenting
Improves long-term outcomes
Helps prioritize treatment in patients with multiple blockages

When Are These Technologies Used?

Cardiologists often use IVUS, OCT, or FFR when:

Angiogram results are unclear
Multiple or complex blockages are present
Planning stenting in critical locations
Evaluating previous stents
Deciding whether to perform angioplasty

They offer a more accurate, patient-specific approach.

IVUS vs OCT vs FFR: A Quick Comparison

Feature	IVUS	OCT	FFR
Technology	Ultrasound (Sound Waves)	Light-based Imaging	Pressure-based Measurement
Resolution	Moderate	High	Not Imaging – Functional Test
Purpose	Artery Wall & Plaque View	High-detail Surface Imaging	Measures Blood Flow Impact
Best For	Stent Planning, Deep Lesions	Surface Detail, Stent Check	Assessing Functional Severity