title: Augmented reality visualization with use of image overlay technology for MR imaging-guided interventions: assessment of performance in cadaveric shoulder and hip arthrography at 1.5 T.
abstract: OBJECTIVE
  To prospectively assess overlay technology in providing accurate and efficient targeting for magnetic resonance (MR) imaging-guided shoulder and hip joint arthrography.
  
  
  METHODS
  A prototype augmented reality image overlay system was used in conjunction with a clinical 1.5-T MR imager. A total of 24 shoulder joint and 24 hip joint injections were planned in 12 human cadavers. Two operators (A and B) participated, each performing procedures on different cadavers using image overlay guidance. MR imaging was used to confirm needle positions, monitor injections, and perform MR arthrography. Accuracy was assessed according to the rate of needle adjustment, target error, and whether the injection was intraarticular. Efficiency was assessed according to arthrography procedural time. Operator differences were assessed with comparison of accuracy and procedure times between the operators. Mann-Whitney U test and Fisher exact test were used to assess group differences.
  
  
  RESULTS
  Forty-five arthrography procedures (23 shoulders, 22 hips) were performed. Three joints had prostheses and were excluded. Operator A performed 12 shoulder and 12 hip injections. Operator B performed 11 shoulder and 10 hip injections. Needle adjustment rate was 13% (six of 45; one for operator A and five for operator B). Target error was 3.1 mm±1.2 (standard deviation) (operator A, 2.9 mm±1.4; operator B, 3.5 mm±0.9). Intraarticular injection rate was 100% (45 of 45). The average arthrography time was 14 minutes (range, 6-27 minutes; 12 minutes [range, 6-25 minutes] for operator A and 16 minutes [range, 6-27 min] for operator B). Operator differences were not significant with regard to needle adjustment rate (P=.08), target error (P=.07), intraarticular injection rate (P>.99), and arthrography time (P=.22).
  
  
  CONCLUSIONS
  Image overlay technology provides accurate and efficient MR guidance for successful shoulder and hip arthrography in human cadavers.
authors: Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 601 N Caroline St, JHOC 5165, Baltimore, MD 21287, USA.
authors: Jan
authors: J
authors: Fritz
authors: Paweena
authors: P
authors: U-Thainual
authors: Tamas
authors: T
authors: Ungi
authors: Aaron J
authors: AJ
authors: Flammang
authors: Gabor
authors: G
authors: Fichtinger
authors: Iulian I
authors: II
authors: Iordachita
authors: John A
authors: JA
authors: Carrino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006621:Hip Joint; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007270:Injections, Intra-Articular / Q000379:methods*; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012785:Shoulder Joint; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media