ivus image interpretation and analysis

Dr Arindam PandeConsultant Cardiologist,

Academic Coordinator: DNB Cardiology and PGDCC Training

Apollo Gleneagles Hospital, Kolkata

“IVUS ImageInterpretation and Analysis”

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Introduction to Intravascular Ultrasound – IVUS

Image by Boston Scientific Corporation

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Comparing Angiography and IVUS

In angiography, angle of view determines what we see.

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Clinical Utility for IVUS

• Stenting of smaller vessels– Vessels ≤ 3mm

• Intra-stent restenosis– Visualize the stent

• Difficult to assess lesions– More sensitive plaque detection

1. Moussa C, et al J Am Coll Cardiol 1997; 29 (Suppl A) 60A

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Image Interpretation

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Lower Density Plaques

Eccentric fibrous plaque Concentric fibro-fatty plaque

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Lower Density Plaques

Eccentric fibrous plaque Concentric fibro-fatty plaque

IVUScatheter

Eccentricfibrousplaque

Lumen

IVUScatheter

Concentricfibro-fattyplaque

LumenMedia

Guidewireartifact

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Mixed Plaque

Mixed eccentric plaque(fibrous, fibro-fatty, and calcified)

Thin concentric fibrous plaquemixed with calcium

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Mixed Plaque

Mixed eccentric plaque(fibrous, fibro-fatty, and calcified)

Thin concentric fibrous plaquemixed with calcium

IVUScatheter

IVUScatheter

Fibro-fattyplaque Media

Guidewireartifact

Calcified plaqueCalcifiedplaque

Fibrousplaque

Fibrousplaque

Guidewireartifact

Fibrousplaque

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Calcified Plaque

90° arc (one quadrant)of deep calcium

Mixed deep and superficialcalcified plaque

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Calcified Plaque

90° arc (one quadrant)of deep calcium

Mixed deep and superficialcalcified plaque

IVUScatheter

Calcifiedplaque

Fibrousplaque

Fibrousplaque

Guidewire artifact

Fibrousplaque

Shadowing (IVUS signaldoes not pass throughcalcified plaque)

Fibrousplaque

Superficialcalcium

IVUScatheter

Superficialcalcium

Reverberations Deep calcium

Shadowing

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Calcified Plaque (continued)

180° arc of eccentric superficialcalcified plaque

270° arc of superficialcalcified plaque

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Calcified Plaque (continued)

180° arc of eccentric superficialcalcified plaque

270° arc of superficialcalcified plaque

IVUS catheter

Calcified plaqueReverberations

IVUS catheter

Lumen

Calcified plaque

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Stents

Fully apposed stent Incompletely apposed stent

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Stents

Fully apposedstent

Incompletely apposedstent

IVUScatheter

IVUScatheter

Apposed

Concentric mixed fibrousand fibro-fatty plaque

Stentstruts

Stentstruts

Vessel wall

UnopposedUnopposed

Apposed

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Stents (continued)

Stent deployment in a heavily calcified vessel

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Stents (continued)

Stent deployment in a heavily calcified vessel

IVUS catheter

Stent struts

Stent struts

Calcified plaque

Guidewire artifactStent struts

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Dissections

Fibrous plaque dissectionextending into the intima

Deep fibro-fatty plaque dissectionextending into the media

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Dissections

Fibrous plaque dissectionextending into the intima

Deep fibro-fatty plaque dissectionextending into the media

Fibrousplaque Fibro-fatty

plaque

Lumen

IVUScatheter

IVUScatheter

Fibro-fattyplaque

Fibro-fattyplaque

Dissection arm Dissectionarm

Fibrousplaque

Media

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Dissections (continued)

Horseshoe dissection of fibrousplaque extending into the media

Horseshoe dissection ofcalcified plaque

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Dissections (continued)

Horseshoe dissection of fibrousplaque extending into the media

Horseshoe dissection ofcalcified plaque

IVUScatheter

Dissectionarm

IVUScatheter

Calcifiedplaque Superficial

calcium

Bloodspeckle

Dissectionarm: calcifiedplaque

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Measurement and Analysis

Maximum plaquethickness

Lumen borderMaximum lumendiameter

Minimum lumendiameter

Minimum plaquethickness

Media-adventitia(MA) border

Measurementsrequiredfor analysisof IVUSimages

Lumen CSA

Plaque CSA

Maximum plaque thicknessMinimum plaque thicknessEccentricity =

Plaque CSA* = MA CSA – Lumen CSA

Plaque CSAMA CSA% Plaque area =

Reference lumen CSA –Lesion lumen CSAReference lumen CSA

% Area stenosis =

* Plaque CSA includes variable amounts of smooth muscle from media

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Measurement and Analysis

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Calculating – Area

D(mm) = 0.0A1 = 5.9mm2

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Lumen Diameter Measurements

2.5

3.0

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IVUS-Guided Stenting• Measurement and Analysis

Lumen Diameters vs. Cross Sectional Areas (CSA)Lumen Diameter

(mm)Lumen CSA

(mm2)90% of Lumen

CSA (mm2)Lumen Diameter at 90% of CSA (mm)

2.5 4.9 4.4 2.43.0 7.0 6.4 2.83.2 8.0 7.2 3.03.4 9.0 8.2 3.2

Minimum Lumen Cross Sectional Area Potential Restenosis Rate

The incidence of restenosis has an inverse relationship to post-procedure absolute IVUS lumen CSA.

<5mm2 46%5.0-5.9mm2 33%6.0-7.9mm2 27%8.0-8.9mm2 21%

≥9mm2 8%

“The Predictive Value of Different Intravascular Ultrasound Criteria for Restenosis After Coronary Stenting”1

1 Moussa et al., ACC 97: 707-6. Data did not include DES.

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39 years RTA patient with sudden chest pain and VT in ER

28

IVUS: Dissection

FL

TL◄

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Take Home Messages

• How to determine lesion length morphology• How to identify dissections• Determining appropriate stent placement• Determining lesion size• Understanding the shortfalls of angiography

Thank You