MR-IMAGING SIGNAL-INTENSITY ABNORMALITIES AFTER PLACEMENT OF ARTERIALENDOPROSTHESES

OBJECTIVE. Our objectives were to describe changes in T2-weighted MR i mages of patients who had undergone implantation of an endoluminal ste nt-graft and determine the rate of early reocclusion in patients with abnormal MR findings. SUBJECTS AND METHODS. Twenty-nine patients with 26 occlusions (average length, 8.7 +/- 5.6 cm) and three dissections o f the superficial femoral artery were treated with 45 endoluminal sten t-grafts. T2-weighted gradient-echo and T2-weighted turbo spin-echo MR images were obtained for all patients at 48 hr and at 4 weeks after s tent-graft placement. We reviewed the MR imaging studies to assess the extent and severity of tissue alteration at the site of stent-graft i mplantation. RESULTS. Technical success rate of stent-graft placement was 100%. Three signal-intensity patterns were seen on MR images obtai ned at 48 hr: normal signal intensity (n = 8), subtle perivascular sig nal-intensity abnormalities at the site of stent-graft implantation (n = 11), and extensive signal-intensity abnormalities from the adductor canal to the subcutis (n = 10). Twenty of 21 patients with abnormal s ignal intensity on MR images had fevers and pain at the implantation s ite. Clinical signs of deep vein thrombosis, a diagnosis excluded on t he basis of phlebography, were seen in the 10 patients with extensive signal-intensity abnormalities. In two of these 10 patients, the super ficial femoral artery reoccluded within 4 weeks of implantation. MR im ages obtained at 4 weeks showed no signal-intensity abnormalities in a ny of the 29 patients. CONCLUSION. MR findings of perivascular signal- intensity abnormalities after implantation of endoluminal stent-grafts are associated with clinical complications such as local pain and fev er. Care should be taken to avoid confusing the clinical signs of the postimplantation syndrome at 48 hr with deep vein thrombosis.