Background: So far, aneurysm volume was expressed by using aneurysm width and length. Using these
parameters received from magnetic resonance angiography (MRA)- maximum intensity projection
(MIP) images, volume of aneurysms was estimated using the cylindric volume formula:
(3.14×[width/2]2×length). Determination of exact aneurysm volume gains importance
in testing liquid embolic polymers. We compare the calculatively derived volume in
saccular, bilobular, broad-based, or bisaccular aneurysms of the rabbit bifurcation
model with MPR segmentational volumetry.
Methods: In 12 female New Zealand white rabbits three of each saccular, broad-based, bilobular,
and bisaccular aneurysms were created using the rabbit venous pouch bifurcation model.
Contrast-enhanced magnetic resonance angiography (CE-MRA) was performed. For all aneurysms
and MIP reconstructions as well as an MPR dataset acquired. Aneurysm width and length
were measured in MIP images, and the volume was calculated using the cylindrical volume
formula. Three-dimensional (3-D) segmentational volumetry using the MPR dataset was
in a semiautomated manner.
Results: The 12 aneurysms had a calculated volume ranging from 53.6 to 503.5 mm3 (mean 186.5±118 mm3) and the MPR segmentational volume ranging from 74.7 to 581.0 mm3 (mean 202.2±133 mm3). The mean relative difference to the MIP cylindrical volume calculation was 24.7%
(range, −77.5±50.8). Only 4 of 12 of the MPR segmentational volumes were within the
10% range of cylindrical volume calculated results, three of these were in broad-based
aneurysms.
Conclusions: This descriptive study demonstrates that an approximate calculation of aneurysm volume
from MRA-MIP images show high differences to MPR segmentational volumetry. With the
increasing acquisition of 3-D data as 3-D-MRA and the rising need of exact volume
determination, studies on the accuracy of computational segmentational volumetry of
CE-MRA have to be undertaken.
