Aneurysm volume-to-ostium area ratio: a parameter useful for discriminating the rupture status of intracranial aneurysms.
BACKGROUND
Slow or stagnant flow is a hemodynamic feature that has been linked to the risk of aneurysm rupture.


OBJECTIVE
To assess the potential value of the ratio of the volume of an aneurysm to the area of its ostium (VOR) as an indicator of intra-aneurysmal slow flow and, thus, in turn, the risk of rupture.


METHODS
Using a sample defined from internal databases, a retrospective analysis of aneurysm size, aspect ratio (AR), and VOR was performed on a series of 155 consecutive aneurysms having undergone 3-dimensional digital subtraction angiography as a part of their evaluation. Measurements were obtained from 3-dimensional digital subtraction angiography studies using commercial software. Aneurysm size, AR, and VOR were correlated with rupture status (ruptured or unruptured). A multiple logistic regression model that best correlated with rupture status was generated to evaluate which of these parameters was the most useful to discriminate rupture status. This model was validated using an independent database of 62 consecutive aneurysms acquired outside the retrospective study interval.


RESULTS
VOR showed better discrimination for rupture status than did size and AR. The best logistic regression model, which included VOR rather than size or AR, determined rupture status correctly in 80.6% of subjects. The reproducibility calculating AR and VOR was excellent.


CONCLUSIONS
Determination of VOR was easily done and reproducible using widely available commercial equipment. It may be a more robust parameter to discriminate rupture status than AR.
Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
Ryuta
R
Yasuda
Charles M
CM
Strother
Waro
W
Taki
Kazuhiko
K
Shinki
Kevin
K
Royalty
Kari
K
Pulfer
Christof
C
Karmonik
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging* / Q000473:pathology; D015901:Angiography, Digital Subtraction; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D012422:Rupture, Spontaneous; D012680:Sensitivity and Specificity