Greater saphenous vein evaluation from computed tomography angiography as a potential alternative to conventional ultrasonography

Objective Autologous greater saphenous vein (GSV) graft is frequently used as a conduit during arterial bypass. Preoperative vein mapping has been traditionally used to assess conduit adequacy and define GSV anatomy, thereby decreasing operative time and reducing wound complications. The purpose of this study was to determine whether GSV mapping using computed tomography angiography (CTA) closely correlated with that of traditional duplex ultrasonography (US). Methods From August 2009 through June 2011, 88 limbs from 51 patients underwent CTA of the lower extremities for the purpose of defining arterial anatomy with concurrent US for preoperative vein mapping. GSV diameters were measured by two blinded reviewers on CTA (both antero-posterior [AP] and lateral dimensions) and compared with US-based measurements at levels of the proximal thigh, mid-thigh, knee, mid-calf, and ankle. CTA and US measurements were compared at each anatomic level using linear regression. Statistical analysis was performed using SPSS software. Charge reduction was calculated based on technical and professional fees for each imaging study. Results GSV diameter sequentially decreased from the proximal thigh to the mid-calf and then increased to the ankle as measured by CTA and US. CTA-based measurements of the GSV significantly correlated with US GSV diameters ( R = 0.927 [lateral dimension], 0.922 [AP dimension]; P < .005). The strongest degree of correlation occurred in measurements at the proximal thigh, followed by the mid-thigh, mid-calf, knee, and ankle. GSV measurement by CTA was over 90% sensitive and accurate for detecting appropriate GSV diameter for bypass (diameter >2.0 mm). Eliminating preoperative US vein mapping for the study patients at our institution would have resulted in charge reductions of $49,316 over the study period. Conclusions Indirect venography by CTA correlates well with US for GSV mapping in the lower extremity and offers significant reduction in imaging-related preoperative charges. CTA is sensitive and accurate for detecting GSVs that are appropriate for bypass. Furthermore, CTA allows AP and lateral evaluation of the GSV throughout its anatomic course. As CTA is often performed prior to arterial bypass, indirect evaluation of the GSV using preoperative CTA should be considered a promising alternative to the use of US.