Multi-slice CT angiography for arterial evaluation in the injured lower extremity

Background., With the evolution of multi-slice helical computed tomographic angiography (MCTA), the optimal imaging modality for arterial injury in the traumatized lower extremity has been challenged. The objective of this study was to evaluate the ability of MCTA to detect arterial injury in the traumatized lower extremity. Our hypothesis was that MCTA is a sensitive and specific test for the non-invasive evaluation of lower extremity arterial injury. Methods: After Institutional Review Board approval, we reviewed all patients at our Level I trauma center who sustained lower extremity trauma and underwent initial evaluation by MCTA over a 3-year period ending in February 2005. MCTA accuracy was tested against a gold standard of operative intervention, duplex ultrasonography, catheter-based angiography, or clinical follow-up. Results: Sixty-three MCTAs were performed in 59 patients. MCTA was diagnostic in 62 of the 63 scans (98.4%). The mechanism was penetrating in 45.8%. Lower extremity fractures were present in 38.7% of patients studied. There were 22 positive studies. Out of this group, 19 were confirmed at operation and 3 were managed non-operatively. In the 19 injuries confirmed in the operating theater, there were 5 superficial femoral, 2 profunda, 10 popliteal, 1 posterior tibial, and I injury to all 3 mid-calf arteries. There were two injuries below the trifurcation managed non-operatively and there was one popliteal occlusion with distal reconstitution that was confirmed by duplex and managed non-operatively because of patient refusal of surgery. Forty studies were negative for arterial injury, with clinical follow up available in 89.5%, for a mean of 48.2 days (range, 5-287 days). No missed injuries were identified during the follow-up period. MCTA was non-diagnostic in I patient (1.6%), secondary to artifact from retained missile fragments. MCTA achieved 100% sensitivity and 100% specificity in detecting clinically significant arterial injury. Conclusion: MCTA is a sensitive and specific non-invasive imaging modality for arterial evaluation in the injured lower extremity that may replace catheter-based angiography in most patients.