title: Flat-panel CT arthrography: feasibility study and comparison to multidetector CT arthrography.
abstract: OBJECTIVE
  To show the feasibility of flat-panel computed tomography (FPCT) arthrography and quantitatively and qualitatively compare different FPCT protocols with standard multidetector computed tomography (MDCT).
  
  
  METHODS
  First, a phantom simulating joint space with increasing iodine concentrations was scanned using a standard MDCT and 3 different FPCT protocols. Quantitative analyses were performed by measuring CT numbers of iodine dilutions, radiation dose, and image noise as well as signal-to-noise ratio and contrast-to-noise ratio. Second, FPCT arthrographies of 4 animal joint specimens were performed and analyzed qualitatively by 2 independent readers who evaluated image artifacts, image noise, overall image quality and anatomic depiction of bone, cartilage, and soft tissue. Kappa values were calculated for inter-reader agreement. Pearson's correlation coefficient (r) and Wilcoxon signed-ranks test with Bonferroni corrections for multiple comparisons were used to compare MDCT and FPCT.
  
  
  RESULTS
  In phantoms, all CT scans showed a linear correlation between increasing iodine concentrations and mean HU values of contrast media and radiation dose, respectively (r = 0.98-0.99, P < 0.01). Dose-length product remained constant for MDCT scans. Signal-to-noise ratio for phantom water linearly decreased in all FPCT scans with increasing iodine concentrations. Contrast-to-noise ratio curves showed reduced slope at iodine concentrations higher than 75 mg/mL. FPCT arthrography after intra-articular administration of 5 to 6 mL of a 25% dilution of iopromide (Ultravist 300 mg/mL, Bayer HealthCare, Berlin, Germany) was successfully performed in all 4 animal joint specimens. Kappa values for inter-reader agreement of qualitative image analyses were 0.62 to 0.91. Image and depiction quality of 20-s FPCT scans were similar or superior compared with standard MDCT (P < 0.005).
  
  
  CONCLUSIONS
  FPCT arthrography is feasible and may allow similar image quality compared with standard MDCT arthrography.
authors.affiliation: Department of Radiology, University Hospital Zurich, Zurich, Switzerland. roman.guggenberger@usz.ch
authors.forename: Roman
authors.initials: R
authors.lastname: Guggenberger
authors.forename: Michael Alexander
authors.initials: MA
authors.lastname: Fischer
authors.forename: Juerg
authors.initials: J
authors.lastname: Hodler
authors.forename: Thomas
authors.initials: T
authors.lastname: Pfammatter
authors.forename: Gustav
authors.initials: G
authors.lastname: Andreisek
mesh_terms: D000818:Animals; D001175:Arthrography / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods