Will Fluoroscopic Follow-up after Stent-Assisted Coiling of Cerebral Aneurysms Provide Information on Recanalization?

Fluoroscopic images for comparison (FICs) can be easily obtained for follow-up on an outpatient basis. This study retrospectively assessed the diagnostic performance of a set of FICs for evaluation of recanalization after stent-assisted coiling, with digital subtraction angiography (DSA) as the reference standard. A total of 124 patients harboring 144 stent-assisted coiled aneurysms were included. At least one month postembolization they underwent follow-up angiograms comprising a routine frontal and lateral DSA and a working-angle DSA. For analysis, FICs should be compared with the mask images of postprocedural DSAs to find recanalization. Instead of FIC acquisition, the mask images of follow-up DSAs were taken as a substitute because of the same view-making processes as FICs, full availability, and perfect coincidence with follow-up DSAs. Two independent readers evaluated a set of 169 FICs and DSA images for the presence of recanalization one month apart. Sensitivity, specificity, and interreader agreement were determined. Recanalization occurred in 24 (14.2%) cases. Of these, nine (5.3%) cases were found to have significant recanalization in need of retreatment. Sensitivity and specificity rates were 79.2% (19 of 24) and 95.9% (139 of 145) respectively for reader 1, and 66.7% (16 of 24) and 97.9% (142 of 145) for reader 2. Minimal recanalization was identified in seven out of all eight false negative cases. Excluding minimally recanalized cases in no need for retreatment from the recanalization group, calculation resulted in high sensitivity and specificity of over 94% for both readers. Interreader agreement between the two readers was excellent (96.4%; κ = 0.84). FICs may be a good imaging modality to detect significant recanalization of stent-assisted coiled aneurysms.