Evaluation of the occlusion status of coiled intracranial aneurysms with MR angiography at 3T: is contrast enhancement necessary?
OBJECTIVE
MR angiography (MRA) is increasingly used as a noninvasive imaging technique for the follow-up of coiled intracranial aneurysms. However, the need for contrast enhancement has not yet been elucidated. We compared 3D time-of-flight MRA (TOF-MRA) and contrast-enhanced MRA (CE-MRA) at 3T with catheter angiography.


METHODS
Sixty-seven patients with 72 aneurysms underwent TOF-MRA, CE-MRA, and catheter-angiography 6 months after coiling. Occlusion status on MRA was classified as adequate (complete and neck remnant) or incomplete by 2 independent observers. For TOF-MRA and CE-MRA, interobserver agreement, intermodality agreement, and correlation with angiography were assessed by kappa statistics.


RESULTS
Catheter-angiography revealed incomplete occlusion in 12 (17%) of the 69 aneurysms; 3 aneurysms were excluded due to MR imaging artifacts. Interobserver agreement was good for CE-MRA (kappa = 0.77; 95% confidence interval [CI], 0.55-0.98) and very good for TOF-MRA (kappa = 0.89; 95% CI, 0.75-1.00). Correlation of TOF-MRA and CE-MRA with angiography was good. The sensitivity of TOF-MRA and CE-MRA was 75% (95% CI, 43%-95%); the specificity of TOF-MRA was 98% (95% CI, 91%-100%) and of CE-MRA, 97% (95% CI, 88%-100%). All 5 incompletely occluded aneurysms, which were additionally treated, were correctly identified with both MRA techniques. Areas under the receiver operating characteristic curve for TOF-MRA and CE-MRA were 0.90 (95% CI, 0.79-1.00) and 0.91 (95% CI, 0.79-1.00). Intermodality agreement between TOF-MRA and CE-MRA was very good (kappa = 0.83; 95% CI, 0.65-1.00), with full agreement in 66 (96%) of the 69 aneurysms.


CONCLUSIONS
In this study, TOF-MRA and CE-MRA at 3T were equivalent in evaluating the occlusion status of intracranial aneurysms after coiling. Because TOF-MRA does not involve contrast administration, this method is preferred over CE-MRA.
Sprengers
M E S
ME
Department Radiology, Academic Medical Center, Amsterdam, the Netherlands. M.E.Sprengers@amc.uva.nl
Schaafsma
J D
JD
van Rooij
W J
WJ
van den Berg
R
R
Rinkel
G J E
GJ
Akkerman
E M
EM
Ferns
S P
SP
Majoie
C B L M
CB
D003287:Contrast Media; D004621:Embolization, Therapeutic / Q000295:instrumentation* / Q000379:methods; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000628:therapy*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
D003287:Contrast Media; D019786:Gadolinium DTPA