Evaluation of In-Stent Restenosis After Stent Implantation in the Vertebral Artery Ostium by Multislice Computed Tomography Angiography: Factors Affecting Accurate Diagnosis.

PURPOSE

Few articles have evaluated vertebral artery ostium stents using multislice computed tomography (CT). The purpose of our study was to evaluate the diagnostic performance of 64- and 16-slice CT for detecting significant in-stent restenosis after vertebral artery ostium stenting, and to identify factors affecting the accurate diagnosis by CT.

METHODS

We reviewed 57 stents scanned using 64-slice CT and 34 stents using 16-slice CT. The accuracy of CT for diagnosing significant in-stent restenosis (≥ 50% diameter narrowing) was calculated using conventional angiography as a reference standard. Possible factors influencing the diagnostic performance of CT were analyzed, such as CT scanner, image quality, and stent characteristics.

RESULTS

With 64-slice CT, 46 (80.7%) of 57 stents were classified as evaluable, while with 16-slice CT, 28 (82.3%) of 34 stents were classified as evaluable. No stents with diameters ≤ 2.75 mm were evaluable. The respective results for 64- versus 16-slice CT were sensitivity 87.5% (95% confidence interval [CI] 47.3-99.7%) versus 100% (95% CI 15.8-100.0%), specificity 94.7% (95% CI 82.3%-99.4%) versus 96.2% (95% CI 80.4-99.9%). Factors reducing the accurate diagnosis were those associated with poor image quality, a diameter ≤ 2.75 mm, and drug-eluting stent type (p < 0.05).

CONCLUSIONS

64-slice and 16-slice CT scans are adequate in stents with diameters > 2.75 mm for the evaluation of in-stent restenosis after stent implantation in the vertebral artery ostium.