PracticeIVUS Beta

Case

Angiogram

Tap the LAD or drag either view to move the imaging position

Longitudinal view

ProximalDistal

Longitudinal cut 1:00 to 7:00

Contours

At this frame

LumenEEMStentMin diameterMax diameter

Lesion and artifact atlas

IVUS, synthetic

Finding Labels

Name the finding

What does this frame show? The frames are the atlas images, shown without labels.

Practice a case

Beta

Decision practice with simulated outcomes. The scoring is a simplified teaching model and may contain errors; focus on the lessons and check decisions against current guidance and your own clinical judgment.

Assess the lesion

Scroll through the pullback, find the minimal lumen area, then mark the most normal-looking frame on each side as a reference.
Plan

Size the stent, choose its length, and decide how to prepare the lesion.

Stent diameter Stent length Lesion preparation
Deploy

Pressure: atm
Optimize

Review the result, then postdilate with a noncompliant balloon where needed. You can repeat this.

NC balloon Pressure: atm Segment
Whole stent Proximal half Distal half

See one approach

Measurement definitions

Position: Distance of the current frame from the start of the pullback (the distal end), derived from the motorized pullback.
Plaque: The reader’s qualitative call of the dominant plaque appearance, e.g. fibrous, calcific, lipid-rich. Grayscale IVUS does not measure tissue type.
Lumen area: Area inside the traced lumen–intima border. The minimal lumen area (MLA) is the smallest lumen area in the segment.
Manual tracing: Planimetry: the operator traces the lumen–intima border and the EEM by hand, and the system calculates the enclosed areas. Automatic borders should always be reviewed; behind calcium the EEM is traced by extrapolating between visible segments.
Lumen diameter: Minimum and maximum diameters, each measured through the center point of the lumen.
Area stenosis: (Reference lumen area − lumen area) ÷ reference lumen area. The reference must be stated; here it is the mean of the proximal and distal reference lumen areas.
Length: Distance between two frames along the pullback, such as from the distal to the proximal reference.
EEM area: Area inside the external elastic membrane, traced at the media–adventitia border. Behind calcium the EEM is hidden by acoustic shadow. Standard practice extrapolates it from the nearest visible EEM when shadowing is limited (classically under 90°). This simulator extrapolates up to 180° and labels the value as extrapolated; beyond 180° it reports “not measurable” and hides the EEM contour.
Plaque area (plaque + media area): EEM area − lumen area. It includes the media, because IVUS cannot reliably delineate the boundary between plaque and media.
Plaque burden: (Plaque + media area) ÷ EEM area, as a percentage. A reference or landing zone is usually expected to have a burden under 50%.
Plaque thickness: Minimum and maximum plaque + media thickness: the distance from the intimal leading edge to the EEM, along lines through the center of the lumen.
Plaque eccentricity index: (Maximum − minimum plaque + media thickness) ÷ maximum plaque + media thickness. Values near 0 indicate concentric plaque, values near 1 eccentric plaque.
Calcium: Arc of calcium in degrees, measured from the lumen center. Calcium is superficial when the leading edge of the acoustic shadow lies in the inner (luminal) half of the plaque + media thickness, and deep when it lies in the outer half. IVUS usually cannot show calcium thickness because of the shadow behind it.
Semi-compliant balloon: Standard predilation balloon whose diameter increases with pressure. Generally effective for soft plaque; often less effective in resistant fibrous or calcified lesions.
NC / super-high-pressure balloon: Noncompliant balloons largely maintain their diameter at high pressure. Super-high-pressure designs may help fracture focal calcium.
Rated burst pressure: The pressure at or below which, in manufacturer testing, 99.9% of balloons are not expected to burst (with 95% confidence). Values vary by device. This simulator flags stent inflations above 18 atm and NC inflations above 20 atm.
Cutting or scoring balloon: Cutting balloons use microblades to create controlled incisions in fibrous or moderately calcified plaque. Scoring balloons use wires to concentrate force along the plaque and may reduce balloon slippage.
Intravascular lithotripsy: Acoustic shockwaves can modify both superficial and deep calcium, with relatively little effect on soft tissue.
Rotational / orbital atherectomy: A diamond-coated burr (rotational) or crown (orbital) modifies mainly superficial calcium to help device delivery and stent expansion. Rotational atherectomy is generally preferred for balloon-uncrossable lesions. Lithotripsy may be added depending on residual calcium.
Excimer laser atherectomy: Laser ablation, used mainly for balloon-uncrossable or undilatable lesions, in-stent restenosis, and underexpanded stents; its effect on heavy calcium is typically modest.
Stent area / MSA: Area inside the stent struts; the minimum stent area (MSA) is the smallest in the stented segment. Absolute target used here: above 5 mm² for a non-left-main vessel on IVUS.
Stent expansion: MSA as a percentage of the reference lumen area. This simulator uses the following criterion: expansion is optimal when the MSA is >5.0 mm² or >90% of the distal reference lumen area.
Malapposition: Struts separated from the vessel wall with blood behind them. Flagged here when the separation exceeds 0.4 mm over more than 1 mm of length.
Edge dissection / landing zone: A tear at or near the stent edge. The simulator uses the following criteria for calling it major: it spans 60° or more of the circumference, is 3 mm or longer, or extends into the media or adventitia. Preferred landing zones should have plaque burden under 50%, and attenuated plaque should be avoided where feasible.

Mintz GS, Nissen SE, Anderson WD, et al. ACC Clinical Expert Consensus Document on Standards for Acquisition, Measurement and Reporting of Intravascular Ultrasound Studies (IVUS). J Am Coll Cardiol. 2001;37(5):1478–1492.
Räber L, Mintz GS, Koskinas KC, et al. Clinical use of intracoronary imaging. Part 1: guidance and optimization of coronary interventions. An expert consensus document of the European Association of Percutaneous Cardiovascular Interventions. Eur Heart J. 2018;39(35):3281–3300.
Zhang M, Matsumura M, Usui E, et al. Intravascular ultrasound-derived calcium score to predict stent expansion in severely calcified lesions. JACC Cardiovasc Interv. 2021.

The thresholds used for scoring are teaching values adapted from these sources; check them against current guidance before clinical use.