Synovial volume vs synovial measurements from dynamic contrast enhanced MRI as measures of response in osteoarthritis.

OBJECTIVE: Synovium is increasingly a target of osteoarthritis (OA) treatment, yet its optimal measurement is unclear. Using dynamic contrast enhanced (DCE) MRI in knee OA patients before and after intraarticular steroid injection, we compared the responsiveness of static synovial volume measures to measures of dynamic changes in synovial enhancement, changes that are strongly related to synovial vascularity. METHODS: Ninety three patients underwent DCE-MRI before and 1-2 weeks after intra-articular injection of 80 mg methylprednisolone. Synovium was segmented and volume, relative enhancement rate (RER), maximum relative enhancement (REmax), late relative enhancement (RElate) and pharmacokinetic parameters (K(trans), ve) were calculated. KOOS (​knee injury and osteoarthritis outcome score) pain score was recorded before and after injection. Standardized change scores were calculated for each parameter. Linear regression and Pearson's correlations were used to investigate the relationship between change in MRI parameters and change in pain. RESULTS: The change in standardized score for the measures of synovial enhancement, RElate and REmax were -0.58 (95% CI -0.79 to -0.37) and -0.62 (95% CI -0.83 to -0.41) respectively, whereas the score for synovial volume was -0.30 (-0.52 to -0.09). Further, change in knee pain correlated more strongly with changes in enhancement (for both REmax and RElate, r = -0.27 (95% CI -0.45 to -0.07)) than with changes in synovial volume -0.15 (-0.35 to 0.05). CONCLUSION: This study suggests DCE-MRI derived measures of synovial enhancement may be more sensitive to the response to treatment and more strongly associated with changes in pain than synovial volume and may be better outcomes for assessment of structural effects of treatment in OA.

Bone marrow lesions in knee osteoarthritis change in 6-12 weeks.

OBJECTIVES: Knee osteoarthritis (OA) is thought to be a slowly evolving disease with glacial changes in cartilage morphology necessitating trials of potential treatments lasting 1-2 years with evidence that over 6 months change in cartilage is not detectable. In contrast to cartilage, bone has the capacity to adapt rapidly, such as after fracture. We tested whether bone marrow lesions (BMLs) change in volume in 6 and 12 weeks, suggesting they may provide evidence of short term fluctuations of joint damage. METHODS: In 62 patients with patellofemoral knee OA (mean age 55.7 years, 59.7% women, mean BMI 31.0), we obtained baseline, 6 and 12 week knee MRIs with contrast enhancement. Of those with BMLs at baseline, we assessed BML volume on the axial proton density fat saturated (FS) images and postcontrast sagittal T1 weighted FS images. We manually segmented BML volumes, testing repeatability of BML volumes in knees remeasured. Using the standard deviation of the difference between repeated measurements to calculate Bland-Altman Limits of Agreement, we determined how much BML volume change represented a change greater than due to chance. RESULTS: Fifty-two patients had BMLs at baseline. Test-retest reliability for BML volume was high (ICC 0.89, 95% CI 0.80-0.97). All knees showed at least some change in BML volume by 6 and 12 weeks. On the axial view at 6 weeks, 20/49 (40.8%) knees showed BML volume changes greater than the limits of agreement with similar results at 12 weeks. BML changes were evenly divided among knees with enlarging and shrinking BMLs. 63.3% of the knees had more than 50% change in BML volume at either 6 or 12 weeks on the axial view and 48.7% on the sagittal view. CONCLUSIONS: Knee BML volumes change in several weeks in many persons with knee OA. To the extent that they could be regarded as treatment targets, trials testing BML effects could avoid the usual prolonged structure modification trials.

Airway management at floor level: a comparison of tracheal intubation using the Macintosh and Airtraq laryngoscopes.

Practitioners providing pre-hospital care during civilian practice and on military operations may be required to perform airway management and tracheal intubation at floor level. It has been shown that intubation using the Airtraq laryngoscope is easier to learn than standard Macintosh laryngoscopy. We hypothesised that the Airtraq would be easier to use and have shorter intubation times than Macintosh intubation. Sixty volunteers attending a medical conference with no prior Airtraq experience, who were skilled in pre-hospital Macintosh intubation, were recruited. Each was required to intubate an anatomically correct manikin at floor level using a Macintosh and Airtraq laryngoscope. The Airtraq was found to be superior in ease of use (VAS 30 mm, P < 0.001), had a shorter total intubation time (19.4seconds) and a higher intubation success rate (P = 0.012) than the Macintosh laryngoscope (VAS 50 mm, 20.4 seconds). Rotating the tracheal tube 90 degrees anticlockwise during loading into the guiding channel, made the Airtraq intubation easier (VAS 30 mm, P = 0.001) and faster (19.4 seconds, P < 0.001) than with standard orientation of the tube (VAS 40 mm, 25.3 seconds). Airtraq intubation may prove to be easier than Macintosh intubation, when utilised in the clinical pre-hospital setting, though randomised controlled clinical trials are required to confirm this.