Role of computed tomographic angiography in the detection and comprehensive evaluation of persistent sciatic artery.

PURPOSE: To define the role of computed tomographic (CT) angiography in the evaluation of persistent sciatic artery and to identify its potential advantages as a diagnostic modality. METHODS: Between July 2002 and August 2004, 307 consecutive patients underwent CT angiography for suspected lower-extremity arterial insufficiency. All CT angiograms were retrospectively reviewed to determine the presence and laterality of persistent sciatic artery and its associated vascular abnormalities, such as aneurysm, thrombus, distal thromboembolism, and atherosclerotic change. The relationship of persistent sciatic artery with adjacent structures, such as sciatic nerve, muscle, accompanying vein, and femoral artery, as well as the presence of other anomalies, was analyzed. Clinical data regarding the presenting symptoms and hospital course were obtained from patient charts. RESULTS: Six persistent sciatic arteries, with or without occlusion, were identified in five female patients (age range, 54 to 80 years). CT angiography revealed unilateral persistent sciatic artery in four patients (left, 3; right, 1) and bilateral persistent sciatic artery in one patient. Aneurysm was present in two (mean size, 26 mm x 20 mm), thrombosis in three, and distal thromboembolism in all six persistent sciatic arteries. All persistent sciatic arteries coursed along the sciatic nerve and continued as popliteal artery. Characteristically, in all these instances, the superficial femoral arteries were hypoplastic and tapered smoothly. Anomalous popliteal venous drainage was noted in all ipsilateral limbs with persistent sciatic artery and even in contralateral limbs with normal superficial femoral artery in all but one. CONCLUSION: CT angiography enables the detection of persistent sciatic artery even in the presence of complete occlusion and is useful in the comprehensive evaluation of various complications and associated venous anomalies. It can potentially be used as the sole imaging modality for persistent sciatic artery.