title: Delayed Computed Tomography Arthrography of Human Knee Cartilage In Vivo.
abstract: OBJECTIVE
  We investigated the feasibility of delayed computed tomography (CT) arthrography for evaluation of human knee cartilage in vivo. Especially, the diffusion of contrast agent out of the joint space and the optimal time points for imaging were determined.
  
  
  METHODS
  Two patients were imaged using delayed CT arthrography and delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) techniques.
  
  
  RESULTS
  Two hours after injection, the concentration of contrast agent in the joint space was still high enough (20% to 24.5% of the initial concentration at 0 minutes) to allow delayed CT arthrography. The half-life of the contrast agent in the joint space varied from 30 to 60 minutes. The contrast agent concentration in patellar and femoral cartilage reached the maximum after 30 and 60 minutes, respectively. According to dGEMRIC, there were no differences between patients. However, in delayed CT arthrography, the penetration of the contrast agent was higher in the osteoarthritic knee cartilage.
  
  
  CONCLUSIONS
  Contrast agent remained in the joint space long enough to enable delayed CT arthrography of cartilage. After 30 minutes, the normalized contrast agent concentration was higher in the cartilage of the osteoarthritic knee in comparison with the healthy knee. To conclude, delayed CT arthrography exhibited potential for use in the clinical evaluation of cartilage integrity.
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio, Finland ; Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Harri T
authors.initials: HT
authors.lastname: Kokkonen
authors.affiliation: Department of Medical Physics, Imaging Centre, Tampere University Hospital, Tampere, Finland.
authors.forename: Antti S
authors.initials: AS
authors.lastname: Aula
authors.affiliation: Department of Orthopaedics, Traumatology and Hand Surgery, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Heikki
authors.initials: H
authors.lastname: Kröger
authors.affiliation: Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Juha-Sampo
authors.initials: JS
authors.lastname: Suomalainen
authors.affiliation: Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.
authors.forename: Eveliina
authors.initials: E
authors.lastname: Lammentausta
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland ; Institute of Clinical Medicine, Clinical Neurophysiology, University of Eastern Finland, Kuopio, Finland.
authors.forename: Esa
authors.initials: E
authors.lastname: Mervaala
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
authors.forename: Jukka S
authors.initials: JS
authors.lastname: Jurvelin
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio, Finland ; Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Töyräs
keywords: cartilage; contrast-enhanced computed tomography (CT); delayed CT arthrography; in vivo; knee; osteoarthritis