Vascular Duplex Ultrasound

What it does

Vascular Duplex Ultrasound reads vascular-lab and bedside studies that combine B-mode, colour and spectral Doppler: carotid duplex after a TIA or stroke, lower-limb venous compression for deep vein thrombosis, including the two- or three-point scans done by emergency physicians, and arterial duplex for peripheral arterial disease.

For each vessel the run returns its findings. Carotid velocities are read from the spectral strips, from the sonographer's on-screen values or from vendor SR, and combined with plaque into a stenosis category; the common carotid far wall is measured for intima-media thickness; compression clips are read segment by segment for compressibility and thrombus; arterial waveforms are classified and stenoses graded by velocity ratio.

Intended use

Decision support for the vascular sonographer, the vascular physician who signs the study, and the emergency doctor deciding whether a leg is positive for DVT. Angle correction and lab-specific velocity criteria change a stenosis grade, so the result names the criteria it applied. Compression clips that do not show full probe pressure are flagged.

Who it is for

Vascular surgeons, angiologists and vascular-medicine physicians, neurologists in stroke units, vascular sonographers, radiologists and emergency physicians. Developers add the run to vascular-lab reporting and stroke or venous-thromboembolism pathways.

Accepted input

• Duplex studies: DICOM Ultrasound Image and Multi-frame objects with B-mode, colour and PW Doppler regions.
• Compression clips: cine of the common femoral, femoral and popliteal veins, with or without calf veins.
• Vendor measurements: Vascular Ultrasound SR objects (TID 5100) and on-screen velocity labels are read and reconciled with the traced spectra.

Requirements

Requirement	Why
Spectral strips with a calibrated velocity axis	PSV, EDV and ratios are read from the spectrum
Angle-corrected ICA and CCA samples	Velocity criteria assume a correct insonation angle
Longitudinal CCA B-mode with a clear far wall	IMT is measured on the far wall
Cine showing full compression of each venous segment	Compressibility is a motion finding; stills are refused for it
SequenceOfUltrasoundRegions calibration	IMT and plaque in millimetres

Optional context

The clinical question (TIA or stroke, suspected DVT, claudication) and the side examined go in clinical_context.

The result

One JSON result in sections with findings, measurements and classifications per vessel and side. Each velocity keeps its provenance: traced by the model, read from the screen or taken from vendor SR.

Section	Content
Carotid stenosis	ICA PSV and EDV, ICA/CCA ratio and plaque, with the stenosis category per side
Carotid intima-media thickness	Far-wall IMT of the common carotid (mean and maximum) and plaque presence
Deep vein thrombosis	Compressibility of each venous segment, intraluminal thrombus and a positive or negative DVT result
Peripheral arterial duplex	Waveform class (multiphasic to monophasic) and stenosis by PSV ratio
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

• Carotid: SRU 2003 carotid consensus velocity criteria; ESVS 2023 carotid guideline.
• IMT: Mannheim carotid intima-media thickness consensus.
• Venous: SRU 2018 consensus on lower-extremity venous ultrasound for DVT.
• Arterial: SVM/SVU 2020 Doppler waveform nomenclature.
• DICOM: SR Vascular Ultrasound Report TID 5100; GSPS for IMT tracings and calipers; Encapsulated PDF.

Grading notes

Carotid stenosis grading is a deterministic rule applied to the velocities shown in the result, so each category can be checked against its numbers. Under the SRU 2003 criteria, an ICA PSV of 125–230 cm/s with visible plaque indicates 50–69 % stenosis, and a PSV above 230 cm/s indicates 70 % or more; the ICA/CCA ratio and EDV support the category. A DVT result applies only to the segments imaged; segments not shown are listed.

Related models

• us/echo and us/echo-tee complete a cardio-embolic stroke work-up.
• us/lung and us/echo join the DVT read in the breathless patient.