Systematic Review on Contrast-Enhanced Duplex Ultrasound for Below-Knee Arterial Imaging
M. Twyford, C. Keohane, D. Westby, S. Maguire, W. Tawfick, S. R. WalshIntroduction:
Peripheral vascular disease (PVD) affects 2% to 4% of the general population, increasing to 15% in those aged 70 years or older. Digital subtraction angiography (DSA) has long been established as the gold standard for imaging the lower limb accurately; however, this is not without complications and risks. At present, there are several other modalities used in lower limb imaging, including duplex, computed tomographic (CT) angiography and magnetic resonance (MR) angiography. Contrast-enhanced ultrasound (CEUS), also termed contrast-enhanced duplex ultrasound (CEDUS), has acceptable sensitivity and specificity for routine clinical use, without the associated complications. Therefore, we performed a systematic review to determine the diagnostic performance of CEUS compared with DSA in patients with PVD.
Methods:
A total of 1026 titles were reviewed through PubMed, Embase and conference abstracts. Studies included were controlled trials and case series. Adults with suspected PVD, use of CEUS, use of formal intra-arterial angiography as the gold standard comparison and enough data to form 2 × 2 contingency tables were used as eligibility criteria. We included papers that focused on below-knee disease. A total of 3 studies met the criteria.
Results:
A total of 39 patients were included across all the 3 studies. Two of the 3 studies included were contrast dose studies, but all 3 directly compared CEUS to formal angiography in patients with suspected PVD. The individual sensitivities were 0.62 (Ubbink), 0.47 (Eiberg) and 0.50 (Coffi), with a pooled sensitivity of 0.53 (0.35-0.71). The individual specificities were 0.71 (Ubbink), 0.94 (Eiberg) and 0.88 (Coffi), with a pooled specificity of 0.87 (0.75-0.95).
Conclusion:
In conclusion, CEUS is inferior to formal angiography based on this review. That said, it does show promise, and only a small number of studies were eligible for review. It would suggest that if CEUS demonstrated an issue with flow, their likely is an issue with flow.