MR imaging signal-intensity abnormalities after placement of arterial endoprostheses.

Abstract

Our objectives were to describe changes in T2-weighted MR images of patients who had undergone implantation of an endoluminal stent-graft and determine the rate of early reocclusion in patients with abnormal MR findings. Twenty-nine patients with 26 occlusions (average length, 8.7 +/- 5.6 cm) and three dissections of the superficial femoral artery were treated with 45 endoluminal stent-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 stent-graft placement. We reviewed the MR imaging studies to assess the extent and severity of tissue alteration at the site of stent-graft implantation. Technical success rate of stent-graft placement was 100%. Three signal-intensity patterns were seen on MR images obtained at 48 hr: normal signal intensity (n = 8), subtle perivascular signal-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 signal intensity on MR images had fevers and pain at the implantation site. Clinical signs of deep vein thrombosis, a diagnosis excluded on the basis of phlebography, were seen in the 10 patients with extensive signal-intensity abnormalities. In two of these 10 patients, the superficial femoral artery reoccluded within 4 weeks of implantation. MR images obtained at 4 weeks showed no signal-intensity abnormalities in any of the 29 patients. MR findings of perivascular signal-intensity abnormalities after implantation of endoluminal stent-grafts are associated with clinical complications such as local pain and fever. Care should be taken to avoid confusing the clinical signs of the postimplantation syndrome at 48 hr with deep vein thrombosis.