PMC4921189_01
Pre-operative computed tomography (CT), CT angiography (CTA), digital subtraction angiography (DSA), noncontrast-enhanced time-of-flight (TOF) imaging, and phase-contrast (PC) imaging. The aneurysm (black and white arrows) was clearly depicted on the combination of axial and coronal orientations. The coronal TOF and the PC images are maximum-intensity projections.
gr1.jpg
PMC4921189_01_gr1.jpg
fig1
The CT scan revealed a large, unruptured, left cavernous internal carotid artery (ICA)-segment aneurysm (Fig. 1).
Cut planes used for flow volume calculations and temporal series of contrast inflow, and cine velocity and derived fluid force. Top: The cut planes (red surfaces) are shown in red over a rendering of the vascular structure and streamlines. Bottom: The upper row shows the contrast agent filling the fundus at 4 Hz; the middle row shows cine frames of the flow velocity; and the lower row shows the fluid force calculated from the Navier-Stokes equation at each pixel. The flow is observed to be higher toward the outer edgeof the aneurysm, while forces are higher in the middle and toward the end where the flow diverts backward.
gr2.jpg
PMC4921189_01_gr2.jpg
fig2
The high-resolution PC MRI-derived velocity measurements confirmed that the velocities toward the periphery of the aneurysm were on the order of 5cm/s, whereas samples in the center of the fundus were around 1.5cm/s (Fig. 2). Figure 2 also shows the force vectors generated by the blood.
Postoperative imaging. The DSA acquisition shows minor filling of the fundus as the contrast agent passes. This was supported by the MRI with noncontrast-enhanced and contrast-enhanced time-of-flight (TOF) and phase-contrast (PC) imaging. The aneurysm still appears large on TOF due to the short T1 of the thrombus. The phase-contrast images show near zero velocity in the aneurysm. Susceptibility-weighted angiography (SWAN), T2-weighted fluid attenuated inversion recovery (FLAIR) imaging, diffusion-weighted imaging (DWI), and a calculated apparent diffusion coefficient (ADC) map transecting the aneurysm are also shown.
gr3.jpg
PMC4921189_01_gr3.jpg
fig3