|
PURPOSE：To evaluate the acute alteration and chronic recovery in muscle perfusion after excision of femoral artery using Multiphase dynamic ce-MRI in a rabbit model of hind-limb muscle ischemia.
METHOD AND MATERIALS：Acute ischemia was induced in right hind-limbs of 14 New-Zealand white rabbits by complete excision of femoral artery. The acute alteration and the chronic recovery of muscle reperfusion were examined respectively prior to and 0.5hr、1 day、3、7、14、21、28、42、56、70 days after excision of femoral artery on a 1.5T MR scanner(Avanto ). A 5mm-thick axial section through the middle of both femurs was imaged using a T1-weighted 2D-FLASH sequence (2s per image). Following 15 baseline acquisitions, a bolus of Gd-DTPA (0.3mmol/kg, 2.0mL/s) was administered and then 265 image acquisitions were obtained. The percent MR signal enhancement of the ROI (2.0 cm2) in bilateral limbs muscle was plotted respectively and the perfusion parameters (arrive time, signal intensity changing rates at 10s, 30s, and enhancement peak height) were analyzed bilaterally.
RESULTS: Prior to excision of femoral artery, there is no significant difference between the perfusion parameters of bilateral limbs muscle. After femoral artery excision, a significant reduction in resting muscle perfusion was only observed at 0.5 hr. post- excision during the 70-day follow-up period in affected hind-limb. A severe reduction of muscle perfusion was observed compared to that before excision : ArriveTime(122±11.58s VS 14.2±0.663s), Signal Intensity changing rates (at 10s, 0.0055±0.002 %/s VS 0.7600±0.091 %/s, at 30s, 0.0172±0.003 %/s VS 0.4776±0.079%/s), Peak Height( 2.676±0.598% VS 23.54±3.206%). Perfusion recovered very slowly during the first 7 days post-excision and faster perfusion recovery was observed from 14 to 28 days, following by a slower recovery till to 70 days. ArriveTime recovered rapidly, reaching to one of control on 21 days post-excision. On 70 days post excision enhancement peak height reached 80% of the perfusion capacity and the recovery of signal intensity changing rates at 10s and 30 s was only about 60%.
CONCLUSION: Multiphase dynamic ce-MR imaging could assess time-dependent changes of muscle perfusion in a rabbit model of hind-limb ischemia. This technique may provide important referring basis for monitoring the therapy effects and estimating the prognosis in limb vascular disease.
|
