title: Optimized intravenous Flat Detector CT for non-invasive visualization of intracranial stents: first results.
abstract: OBJECTIVE
  As stents for treating intracranial atherosclerotic stenosis may develop in-stent re-stenosis (ISR) in up to 30%, follow-up imaging is mandatory. Residual stenosis (RS) is not rare. We evaluated an optimised Flat Detector CT protocol with intravenous contrast material application (i.v. FD-CTA) for non-invasive follow-up.
  
  
  METHODS
  In 12 patients with intracranial stents, follow-up imaging was performed using i.v. FD-CTA. MPR, subtracted MIP and VRT reconstructions were used to correlate to intra-arterial angiography (DSA). Two neuroradiologists evaluated the images in anonymous consensus reading and calculated the ISR or RS. Correlation coefficients and a Wilcoxon test were used for statistical analysis.
  
  
  RESULTS
  In 4 patients, no stenosis was detected. In 6 patients RS and in two cases ISR by intima hyperplasia perfectly visible on MPR reconstructions of i.v. FD-CTA were detected. Wilcoxon's test showed no significant differences between the methods (p > 0.05). We found a high correlation with coefficients of the pairs DSA/ FD-CT MIP r = 0.91, DSA/ FD-CT MPR r = 0.82 and FD-CT MIP/ FD-CT MPR r = 0.8.
  
  
  CONCLUSIONS
  Intravenous FD-CTA could clearly visualise the stent and the lumen, allowing ISR or RS to be recognised. FD-CTA provides a non-invasive depiction of intracranial stents and might replace DSA for non-invasive follow-up imaging.
authors: Department of Neuroradiology, University of Erlangen-Nuremberg, Erlangen, Germany. tobias.struffert@uk-erlangen.de
authors: Tobias
authors: T
authors: Struffert
authors: Stephan
authors: S
authors: Kloska
authors: Tobias
authors: T
authors: Engelhorn
authors: Yu
authors: Y
authors: Deuerling-Zheng
authors: Sabine
authors: S
authors: Ott
authors: Marc
authors: M
authors: Doelken
authors: Marc
authors: M
authors: Saake
authors: Martin
authors: M
authors: Köhrmann
authors: Arnd
authors: A
authors: Doerfler
mesh_terms: D000368:Aged; D001807:Blood Vessel Prosthesis; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D002533:Cerebral Angiography / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015607:Stents; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D014963:X-Ray Intensifying Screens