Quantitative 2D Digital Subtraction Venography for Venous Interventions: Validation in Phantom and In Vivo Porcine Models.

ABSTRACT

PURPOSE: To determine the feasibility of using a 2D quantitative digital subtraction venography (qDSV) technique that employs a temporally modulated contrast injection to quantify blood velocity in phantom, normal, and stenotic porcine iliac vein models. MATERIALS AND METHODS: Blood velocity was calculated using qDSV following temporally-modulated, pulsed injections of iodinated contrast medium, and compared to Doppler ultrasound (US) measurements (phantom in-line sensor, in vivo diagnostic linear probe). Phantom evaluation was performed in a compliant polyethylene tube phantom with simulated venous flow. In vivo evaluation of qDSV was performed in normal (n=7) and stenotic (n=3) iliac vein models. Stenoses were created using endovenous radiofrequency ablation and blood velocities were determined at baseline, post-stenosis, post-venoplasty and post-stent placement. RESULTS: In the phantom model, qDSV-calculated blood velocities (12-50 cm/s) had very strong correlations with US-measured velocities (13-51 cm/s) across a range of baseline blood velocities and injection protocols (slope=[1.01-1.13], R2=[0.96-0.99]). qDSV velocities were similar to US regardless of injection method: custom injector, commercial injector, or hand injection. In the normal in vivo model, qDSV-calculated velocities (5-18 cm/s) had strong correlation (slope=1.22, R2=0.90) with US (3-20 cm/s). In the stenosis model, blood velocity at baseline, post-stenosis, post-venoplasty, and post-stent placement were similar on qDSV and US at all time points. CONCLUSION: Venous blood velocity was accurately quantified in a venousphantom and in vivo porcine models using qDSV. Intra-procedural changes in porcine iliac vein blood velocity were quantified with qDSV after creation of a stenosis and subsequently treating it with venoplasty and stent placement.