title: Comparison of digital flat-panel detector and conventional angiography machines: evaluation of stent detection rates, visibility scores, and dose-area products.
abstract: OBJECTIVE
  The objective of this study was to compare the performance and radiation doses of a flat-panel detector (FPD) angiography machine with an image intensifier (II) angiography machine.
  
  
  METHODS
  Images of four nitinol stents (Sinus-SuperFlex, SMART, Luminexx, and Zilver stents) in a phantom of a human pelvis were acquired on an FPD system (Axiom Artis) and an II system (Fluorospot TOP) using the following modes: spot-film, continuous fluoroscopy (4, 7.5, 15, and 30 pulses/s), and three amplification modes. Objective stent detection rates and subjective radiopacity scores (scale: 0 [not visible] to 4 [excellent visibility]) were calculated. The radiation doses evaluated by the respective machines were compared.
  
  
  RESULTS
  Over all modes and stents, the mean objective correct stent detection rates and mean subjective radiopacity scores were 89.49% and 1.81, respectively, for the Axiom Artis and 91.00% and 2.26 for the Fluorospot TOP. The stent detection rates over all modes for the SMART and Luminexx stents were better using the Axiom Artis machine (97.61% vs 93.55% and 98.28% vs 90.41%, respectively) and those for the Sinus-SuperFlex and Zilver stents were better using the Fluorospot TOP machine (90.83% vs 83.56% and 89.29% vs 80.50%). The subjective radiopacity scores of stent visibility were worse for the Axiom Artis than the Fluorospot TOP for all stents except the Luminexx stent (mean score, 2.34 vs 2.21, respectively). The objective stent detection rates and subjective radiopacity scores improved using the spot-film mode and with raising amplification, whereas increases in the fluoroscopy pulsing frequency did not improve stent detection rates or radiopacity scores for either machine. The radiation doses at continuous fluoroscopy were approximately 90% higher for the Axiom Artis than for the Fluorospot TOP (2.60 vs 1.41 μGy/m(2) at 30 pulses/s, respectively).
  
  
  CONCLUSIONS
  The objective correct stent detection rates were similar for both machines with differences in detection for the respective stents. The subjective radiopacity scores were almost always better for the Fluorospot TOP machine. Also, the Axiom Artis machine generated approximately 90% higher radiation doses in fluoroscopy. For both machines, using a higher fluoroscopy pulsing frequency had no positive effect on objective correct stent detection rates or subjective radiopacity scores.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tübingen, Germany. benjamin.wiesinger@med.uni-tuebingen.de
authors.forename: Benjamin
authors.initials: B
authors.lastname: Wiesinger
authors.forename: Alexander
authors.initials: A
authors.lastname: Stütz
authors.forename: Jörg
authors.initials: J
authors.lastname: Schmehl
authors.forename: Claus Detlef
authors.initials: CD
authors.lastname: Claussen
authors.forename: Jakub
authors.initials: J
authors.lastname: Wiskirchen
mesh_terms: D000497:Alloys; D000792:Angiography / Q000295:instrumentation*; D005471:Fluoroscopy / Q000295:instrumentation; D006801:Humans; D010388:Pelvis / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D011474:Prosthesis Design; D011829:Radiation Dosage; D018709:Statistics, Nonparametric; D015607:Stents; D014963:X-Ray Intensifying Screens
chemical_list: D000497:Alloys; C013616:nitinol