Intravascular Ultrasound (IVUS)

What it does

Intravascular Ultrasound reads one coronary IVUS pullback offline, independent of the console it was recorded on. The run traces the lumen and the external elastic membrane (EEM) along the whole pullback and turns the contours into the measurements an IVUS-guided PCI depends on.

Before stenting, it returns the minimal lumen area (MLA) and its site, plaque burden and remodelling along the vessel, calcium arc and length, and stent-sizing references with landing zones. After stenting, it returns minimal stent area, expansion, malapposition, edge dissection and geographic miss.

Intended use

Decision support for interventional cardiologists who use IVUS occasionally or want a second, core-lab style measurement: sizing before PCI, plaque-modification decisions before stenting heavy calcium, and stent optimisation after it. It also supports teaching and the review of archived pullbacks.

Who it is for

Interventional cardiologists, cardiology fellows learning intravascular imaging, imaging core labs and trial teams. The vendor-neutral output lets pullbacks from different consoles be measured the same way.

Accepted input

• IVUS pullback: one Ultrasound Multi-frame Image object with the IVUS acquisition attributes, gated or non-gated.
• One run reads one pullback; pre- and post-PCI pullbacks of the same vessel are separate runs.

Requirements

Requirement	Why
IVUSAcquisition and IVUSPullbackRate	Frame spacing along the vessel in millimetres comes from the motorised pullback rate
IVUSPullbackStartFrameNumber / IVUSPullbackStopFrameNumber	Defines the analysed segment
IVUSGatedRate for gated pullbacks	Gated frames are used as recorded; non-gated pullbacks are gated to end-diastole

Non-uniform rotational distortion, catheter motion, side branches and attenuated plaque affect contour placement; the affected frames are flagged.

Optional context

The clinical stage (pre-PCI, post-PCI, follow-up), the target vessel and lesion, and the stent already implanted can be passed in clinical_context; they label the pullback in the result.

The result

One structured result per pullback: frame-wise contours, area and diameter tables, findings and the frames that show them.

Section	Content
Lumen and EEM segmentation	Lumen and EEM contours on every end-diastolic frame, with area and diameter tables
Plaque burden and MLA	Plaque burden along the pullback, MLA and its site, remodelling index, attenuated plaque
Calcium	Calcium arc and length, calcified ring and nodule, and the IVUS calcium score
Stent sizing	Proximal and distal reference EEM and lumen diameters, landing zones, suggested stent diameter and length
Stent optimisation	Minimal stent area, expansion, malapposition, edge dissection and geographic miss
Draft report	Opt-in (options.report): an English narrative that interprets the result for the reader (findings, impression, limitations); every number is checked against the findings

Standards

• DICOM: IVUS Report TID 3250 (vessel TID 3251, lesion TID 3252, measurements TID 3253, qualitative assessments TID 3254, volume measurements TID 3255); SEG for lumen and EEM contours; Secondary Capture of key frames. Plaque is coded with CID 3495 IVUS Plaque Composition, morphology with CID 3491 and CID 3497.
• Definitions: ACC clinical expert consensus on IVUS acquisition, measurement and reporting (Mintz, JACC 2001).
• Optimisation: EAPCI expert consensus on intracoronary imaging for PCI optimisation (Räber, EHJ 2018).
• Calcium: IVUS calcium score (Zhang, Circ Cardiovasc Interv 2021).

Measurement notes

Plaque burden is (EEM area − lumen area) / EEM area on each frame, so it includes the media; MLA, remodelling and landing zones derive from the same contours, so every reported value can be traced to the frames that produced it.