Comparison of remnant size in embolized intracranial aneurysms measured at follow-up with DSA and MRA.
BACKGROUND
The possibility of recanalization and the need for retreatment are the most important limitations of intracranial aneurysm embolization. The purpose of the study was to compare the size of aneurysm remnants measured at follow-up with three-dimensional digital subtracted angiography (3D-DSA) and magnetic resonance angiography (MRA).


METHODS
Twenty-six aneurysms were found incompletely occluded in 72 consecutively examined patients at a follow-up after 3 months. The diameters and volume of aneurysm remnants were compared between 3D-DSA, time-of-flight MRA (TOF-MRA), contrast-enhanced TOF-MRA (CE-TOF-MRA), and contrast-enhanced MRA (CE-MRA) at 1.5 T.


RESULTS
There was a significant correlation between remnant volumes calculated based on 3D-DSA and all MRA modalities. The intraobserver variability of the measurements ranged from 3.4 to 4.1 % and the interobserver variability from 5.8 to 7.3 %. There were no significant differences in the variability between the techniques. The mean residual filling volume ranged from 16.3 ± 19.0 mm(3) in TOF-MRA to 30.5 ± 44.6 mm(3) in 3D-DSA (P < 0.04). Significant differences were found in the volumes measured with 3D-DSA and CE-MRA as compared to TOF-MRA and CE-TOF-MRA (P < 0.01). There was a moderate significant correlation between the residual filling and the relative error of measurement in the case of TOF-MRA and CE-TOF-MRA.


CONCLUSIONS
TOF-MRA seems to underestimate the size of aneurysm remnants detected at follow-up and should not be used as a sole imaging method to decide on re-embolization.
Department of Radiology and Diagnostic Imaging, Collegium Medicum, Nicolaus Copernicus University, ul. M. Skłodowskiej-Curie 9, 85-094, Bydgoszcz, Poland. serafin@cm.umk.pl
Zbigniew
Z
Serafin
Piotr
P
Strześniewski
Władysław
W
Lasek
Wojciech
W
Beuth
D000704:Analysis of Variance; D015901:Angiography, Digital Subtraction / Q000379:methods*; D003287:Contrast Media; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000628:therapy*; D007472:Iohexol / Q000031:analogs & derivatives; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D019233:Retreatment; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
D003287:Contrast Media; D007472:Iohexol; C038192:iopromide