الفهرس 
AIM OF THE WORKOnly 14 pages are availabe for public view
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Abstract
Postoperative surveillance of peripheral arterial bypass grafts is considered to be important, since as many as 30% of patients develop graft-related complications within the first 2 years after surgery. Timely identification of failing grafts can often avert impending graft failure and improve the secondary bypass graft patency rate. Residual valve cusps, anastomotic strictures, arteriovenous fistulas, poor distal run-off, fibrin-platelet aggregates, intimal flaps, and other technical imperfections may lead to early graft failure. More late complications of peripheral arterial bypass grafts include intimal hyperplasia of the graft or progression of the atherosclerosis, which results in graft stenosis.
The use of duplex US in the postoperative surveillance of peripheral bypass grafts is well documented. Duplex US can demonstrate graft patency and enables detection of complications, including stenosis or occlusion, perigraft fluid collections, arteriovenous fistulas, and pseudoaneurysms. Because of its noninvasive quality, low cost, and the rapid access it provides, duplex US is considered to be the primary imaging modality for use in postoperative graft surveillance (Willmann, et al 2003).
Multi–detector row CT angiography allows an accurate depiction of graft-related complications, including stenosis, occlusion, aneurysmal changes, arteriovenous fistulas and infection. Sensitivity and specificity values of more than 95% were achieved with multi–detector row CT angiography for the diagnosis of arterial bypass graft–related complications (Willmann, et al 2003).
CTA has proven to be a powerful tool in evaluating lower extremity bypass grafts. It is well tolerated by patients and it has become preferred over traditional angiography and magnetic resonance angiography. As CTA provides the requisite angiographic information, and demonstrates all soft tissues.
CTA is now used as the sole angiographic imaging study before bypass graft revision since not only are bypass grafts imaged, but target vessel anatomy for reconstruction is seen, as well (Toomay & Dolmatch 2006).
All these findings suggest that multi–detector row CT angiography must be incorporated into a comprehensive graft assessment strategy as a secondary morphologic modality after functional assessment of the bypass graft with duplex US and better delineation of any potential problems detected with duplex US (Willmann, et al 2003).