Detection of perivenous inflammation in a rat model of venous thrombosis using MRV

Venous thrombosis is associated with a significant inflammatory response in the vein wall, which can be imaged noninvasively with gadolinium (Gd)-enha nced magnetic resonance venography (MRV). Interleukin-10 (IL-10), a natural ly occurring anti-inflammatory cytokine, has been found to decrease the inf lammatory response at the proper dosage and timing of administration. The p resent study determines if MRV with Gd is useful in a rat model of stasis-i nduced venous thrombosis to document the anti-inflammatory effects of rIL-1 0. Rats underwent laparotomy and ligation of the inferior vena cava (IVC), Animals were infused with rIL-10 at 2.5 mu g (n = 6), rIL-10 at 10 mu g (n = 6), or rIL-10 at 40 mu g (n = 6). Six animals without IVC ligation or dru g infusion served as controls. Two days after thrombosis induction, the rat s underwent MRV with both time-of-flight imaging and pre/post-Gd T1-weighte d imaging. Inflammation was analyzed by measuring the area of Gd enhancemen t at the point of IVC thrombosis. Enhancement area was also measured in the distal IVC where flow persisted. All animals with IVC ligation developed t hrombosis, and all control rats were free of thrombus. In areas where flow remained, the area of enhancement was 1.8 +/- 0.4 mm(2), while controls dem onstrated 3.8 +/- 1.0 mm(2) enhancement. Enhancement was significantly grea ter in all groups at the level of thrombus compared to the area of distal I VC flow and control IVCs (p < .001). Animals receiving rIL-10 at 40 mu g re vealed the most enhancement, 32.7 +/- 6.2 mm(2), while the least enhancemen t was noted with 2.5 mu g, 14.7 +/- 1.5 mm(2) (P < .05). In conclusion, Gd- enhanced MRV was found useful in this rat model of stasis-induced venous th rombosis to document inflammation noninvasively and to evaluate the effects of anti-inflammatory interventions during stasis-induced IVC venous thromb osis.