Time-of-flight magnetic resonance angiography for follow-up of coil embolization with enterprise stent for intracranial aneurysm: usefulness of source images.
OBJECTIVE
The aim of this study was to determine the interobserver and intermodality agreement in the interpretation of time-of-flight (TOF) MR angiography (MRA) for the follow-up of coiled intracranial aneurysms with the Enterprise stent.


METHODS
Two experienced neurointerventionists independently reviewed the follow-up MRA studies of 40 consecutive patients with 44 coiled aneurysms. All aneurysms were treated with assistance from the Enterprise stent and the radiologic follow-up intervals were greater than 6 months after the endovascular therapy. Digital subtraction angiography (DSA) served as the reference standard. The degree of aneurysm occlusion was determined by an evaluation of the maximal intensity projection (MIP) and source images (SI) of the TOF MRA. The capability of the TOF MRA to depict the residual flow within the coiled aneurysms and the stented parent arteries was compared with that of the DSA.


RESULTS
DSA showed stable occlusions in 25 aneurysms, minor recanalization in 8, and major recanalization in 11. Comparisons between the TOF MRA and conventional angiography showed that the MIP plus SI had almost perfect agreement (κ = 0.892, range 0.767 to 1.000) and had better agreement than with the MIP images only (κ = 0.598, range 0.370 to 0.826). In-stent stenosis of more than 33% was observed in 5 cases. Both MIP and SI of the MRA showed poor depiction of in-stent stenosis compared with the DSA.


CONCLUSIONS
TOF MRA seemed to be reliable in screening for aneurysm recurrence after coil embolization with Enterprise stent assistance, especially in the evaluation of the SI, in addition to MIP images in the TOF MRA.
Department of Radiology, Seoul National University College of Medicine, Seoul 110-744, Korea.
Young Dae
YD
Cho
Department of Radiology, Seoul National University College of Medicine, Seoul 110-744, Korea.
Kang Min
KM
Kim
Department of Radiology, Seoul National University College of Medicine, Seoul 110-744, Korea.
Woong Jae
WJ
Lee
Department of Radiology, Seoul National University College of Medicine, Seoul 110-744, Korea.
Chul-Ho
CH
Sohn
Department of Neurosurgery, Seoul National University College of Medicine, Seoul 110-744, Korea.
Hyun-Seung
HS
Kang
Department of Neurosurgery, Seoul National University College of Medicine, Seoul 110-744, Korea.
Jeong Eun
JE
Kim
Department of Radiology, Seoul National University College of Medicine, Seoul 110-744, Korea. ; Department of Neurosurgery, Seoul National University College of Medicine, Seoul 110-744, Korea.
Moon Hee
MH
Han
D015901:Angiography, Digital Subtraction / Q000379:methods; D002533:Cerebral Angiography / Q000379:methods; D004621:Embolization, Therapeutic / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000628:therapy*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012008:Recurrence; D012015:Reference Standards; D015607:Stents
Aneurysm; Coiling; Embolization; MRA; Stent