Using Porous Media Theory to Determine the Coil Volume Needed to Arrest Flow in Brain Aneurysms - Porous Media: Applications in Biological Systems and Biotechnology - page 243

VELOCITY (m/sec)
TIME 3.311

0.6605

0.6500

0.5500
0.4500
0.3500

0.2500

0.1500

0.0500

Peak systole

VELOCITY (m/sec)
TIME 3.481

0.2000

0.4200
0.3600
0.3000
0.2400

0.1800

0.1200

0.0600

During deceleration

FIGURE 6.5
Temporal variation of the flow patterns a narrow-necked aneurysm with a 20%
filling of coils.

aneurysm sac volume ( V sac ) and the filling density (i.e., volume of the coil) by
the following formula:

V coil
πR coil

= (1

ε ) V sac
πR coil

−

L coil = (6.6)

This simple formula provides a guideline to the surgeons on the minimum
required length of coil that needs to be inserted to arrest flow in the aneurysm
sac. Figure 6.7 shows the treatment of a basilar aneurysm using endovascular
coil.