रुमेटोलॉजी: वर्तमान शोध
खुला एक्सेस

अमूर्त

Responsiveness of Bold MRI to Short-Term Temperature Changes in Rabbit Knees with Inflammatory Arthritis

Cristina Nasui, George Nathanael, Elka Miller, Jaques Belik, Adrian Crawley, Ruth Weiss, Garry Detzler, Anguo Zhong, Rahim Moineddin and Andrea S Doria

Objectives: Tissue signal change caused by temperature-dependent alterations in the affinity of oxygen for hemoglobin contributes to BOLD contrast. Our goals were to test whether BOLD MRI contrast changes with short-term variations in joint temperature (internal responsiveness) and to determine whether an association exists between BOLD MRI and intraarticular pO2 and blood flow [reference standards] upon joint temperature changes (external responsiveness).

Methods: Seven juvenile rabbits had the carrageenin (antigen)-injected knee imaged, 10 had the contralateral knee imaged and 11 had one of non-injection knees imaged. Assigned knees underwent experimentally forced increased (37°-42°C) or decreased (37°- 30°C) local temperature for 15-minute periods using heating/cooling pads and were subsequently imaged. Intra-articular pO2 and blood flow were measured in vivo during MRI scanning by polarographic probes.

Results: Relative BOLD MRI measurements showed moderate (≤0.8 and >0.5) or large (>0.8) Standardized Response Mean (SRM) changes upon increased local temperature in contralateral knees. Significant substantial correlations were obtained between absolute BOLD MRI measurements and intraarticular pO2 measurements in contralateral knees (r = 0.71, P = 0.048) upon increased local temperature and high correlations were obtained in arthritic knees (r = 0.92, P = 0.004) upon decreased local temperature.

Conclusions: BOLD MRI was responsive to short-term joint temperature changes. Imaging contralateral joints in addition to arthritic joints with BOLD MRI may help maximize identification of minimal early changes in subjects with arthritis if findings of this study are confirmed in larger sample size experiments.