Estimation of fusiform intracranial aneurysm growth by serial magnetic resonance imaging.
OBJECTIVE
Intracranial aneurysm (IA) growth is associated with increased morbidity. We sought to establish a quantitative computational method based on contrast-enhanced MR angiography (CE-MRA) for estimating aneurysmal volume changes over time.


METHODS
Computational volume calculations were tested against a distensible phantom. Untreated patients with IA were followed longitudinally with annual MRI. Maximal linear dimensions along the longitudinal axis and two transverse axes were determined by visual review of maximum intensity projection (MIP) data, and aneurysm volume was approximated as (length x width x height)/2. Averages of the visual approximations were compared to the lumenal volume as determined with a computational algorithm using the MRI data.


RESULTS
MRI-based measurements accurately represented volume changes in the phantom (R2 = 0.97, Y = 1.06x + 271 CM3). In the clinical study there were a total of 11 intervals of one-year follow-up in six patients (mean +/- SD, age = 53 +/- 20 years). The raw one-year growth using the computational volume was 9% +/- 17%. The corresponding value for the averaged measurement of the reviewers was 8% +/- 14%. Neither the mean values nor the SDs were different (P = .51).


CONCLUSIONS
MRI-based measurement of aneurysm volume appears feasible for longitudinal studies of aneurysm natural history.
Department of Anesthesia and Perioperative Care and Center for Cerebrovascular Research, University of California-San Francisco, San Francisco, California 94110, USA.
Bradley P
BP
Dispensa
David A
DA
Saloner
Gabriel
G
Acevedo-Bolton
Achal S
AS
Achrol
Lianger-der
LD
Jou
Charles E
CE
McCulloch
S Claiborne
SC
Johnston
Randall T
RT
Higashida
Christopher F
CF
Dowd
Van V
VV
Halbach
Nerissa U
NU
Ko
Michael T
MT
Lawton
Alastair J
AJ
Martin
Nancy
N
Quinnine
William L
WL
Young
D000328:Adult; D000368:Aged; D000465:Algorithms; D003287:Contrast Media; D018450:Disease Progression; D005240:Feasibility Studies; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002532:Intracranial Aneurysm / Q000473:pathology*; D016014:Linear Models; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D013997:Time Factors
D003287:Contrast Media; D019786:Gadolinium DTPA