Diagnostic Performance of Computed Tomography Angiography in Peripheral Arterial Disease: a Systematic Review and Meta-analysis

Context: Computed tomography angiography (CTA) is an increasingly attractive imaging modality for assessing lower extremity peripheral arterial disease (PAD).

Objective: To determine the accuracy of CTA compared with intra-arterial digital subtraction angiography (DSA) in differentiating extent of disease in patients with PAD.

Data Sources And Study Selection: Search of MEDLINE (January 1966-August 2008), EMBASE (January 1980-August 2008), and the Database of Abstracts of Reviews of Effectiveness for studies comparing CTA with intra-arterial DSA for PAD. Eligible studies compared multidetector CTA with intra-arterial DSA, included at least 10 patients with intermittent claudication or critical limb ischemia, aimed to detect more than 50% stenosis or arterial occlusion, and presented either 2 x 2 or 3 x 3 contingency tables (< or = 50% stenosis vs > 50% stenosis or occlusion), or provided data allowing their construction.

Data Extraction: Two reviewers screened potential studies for inclusion and independently extracted study data. Methodological quality was assessed by using the QUADAS instrument.

Data Synthesis: Of 909 studies identified, 20 (2.2%) met the inclusion criteria. These 20 studies had a median sample size of 33 (range, 16-279) and included 957 patients, predominantly with intermittent claudication (68%). Methodological quality was moderate. Overall, the sensitivity of CTA for detecting more than 50% stenosis or occlusion was 95% (95% confidence interval [CI], 92%-97%) and specificity was 96% (95% CI, 93%-97%). Computed tomography angiography correctly identified occlusions in 94% of segments, the presence of more than 50% stenosis in 87% of segments, and absence of significant stenosis in 96% of segments. Overstaging occurred in 8% of segments and understaging in 15%.

Conclusion: Computed tomography angiography is an accurate modality to assess presence and extent of PAD in patients with intermittent claudication; however, methodological weaknesses of examined studies prevent definitive conclusions from these data.