Fig 1.
a) Sketch of the idealized aneurysm geometry representing a typical candidate of a saccular malformation occurring in the neurovasculature; b) Phase-averaged flow rate as measured by the ultrasound flow meter.
Fig 2.
Illustration of the investigated treatment scenarios with Flow Diverter Cases 1 to 4 (FDC1 to FDC4).
The real deployment within the silicone phantom model is shown (FDC1-FDC3: phantom mostly filled with index matching fluid, FDC4: phantom filled with water leading to slight refractions) as well as the PIV measurement plane containing a detailed view of the flow diverter location resulting from long exposure flow tracer reconstructions (upper right corner).
Fig 3.
(a) Principle sketch of the stereoscopic PIV setup involving laser (1), sheet optics (2), acrylic glass box with the phantom (3), flow meter (4) and gear pump (5); (b) Detailed view of (a) as seen from behind with the stereoscopic PIV camera pair (6); (c) Photography of the real measurement setup including the straight inlet tubing (7) as well as the estimated propagation of the laser light sheet.
Fig 4.
Flow measurements with and without tracer particles.
Illustration of the illuminated phantom model containing a representative endovascular device (left); Addition of PIV fluorescent tracer particles revealing the vortical flow structure within the intracranial aneurysm (right).
Fig 5.
Qualitative PIV measurement results.
Comparison of all treatment configurations (FDC1-4) at ten time steps during the cardiac cycle. Notice the clear differences of each FD efficacy compared to the pre-treatment scenario in the first row.
Table 1.
Quantification of the relative velocity reduction of each FD case referring to the untreated aneurysmal flow.
For all configurations both peak-systolic as well as cycle-averaged values are provided.
Fig 6.
Quantitative PIV measurement results.
a) Location of processed flow area (red) and velocity probes (P1 –inflow jet; P2 –aneurysm dome; P3 –close to the proximal area of the ostium); b) Quantification of the cycle-averaged and peak-systolic velocity reduction for each considered deployment scenario. Temporal velocity profiles over the averaged cardiac cycle at three characteristic probe locations in the aneurysm.
Fig 7.
Illustration of the oscillatory velocity index (OVI) to account for device-induced disturbance of the time-dependent flow fields.
From left to right: no FD, FDC1, FDC2, FDC3, FDC4.