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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 ( 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

CONTEXT: Magnetic resonance angiography (MRA) is a rapidly evolving technique that has been reported to be accurate for assessment of lower extremity arterial disease. OBJECTIVE: To obtain the best available estimates of the diagnostic performance of MRA in patients with lower extremity arterial disease. DATA SOURCES: Studies published from January 1985 through May 2000 in English, German, or French, identified from the MEDLINE, EMBASE, and Current Contents databases. STUDY SELECTION: Studies were included that allowed construction of 2 x 2 contingency tables for detection of stenosis greater than 50% or occlusion with MRA or arteriography in patients with claudication or critical ischemia. DATA EXTRACTION: Two observers graded the following elements of study quality: consecutively enrolled patients, prospective study design, clear cut-off levels, blinded assessment, and clear description of MRA technique. Summary receiver operating characteristic analysis was performed to examine the influence of year of publication, all methodological criteria, arterial tract, number of subdivisions within arterial tracts, and MRA technique on diagnostic performance. DATA SYNTHESIS: Of 3583 studies initially identified, 34 were included that evaluated MRA in 1090 patients (72% men; median age, 65 years). Magnetic resonance angiography was highly accurate for assessment of all lower extremity arteries. Three-dimensional gadolinium-enhanced (3-D Gd) MRA improved diagnostic performance compared with 2-D MRA (relative diagnostic odds ratio, 2.8 [95% confidence interval, 1.2-6.4]), adjusted for number of subdivisions within arterial tracts. The estimated points of equal sensitivity and specificity were 94% and 90% for 3-D Gd MRA and 2-D MRA, respectively. CONCLUSIONS: Magnetic resonance angiography is highly accurate for assessment of the entire lower extremity for arterial disease. Three-dimensional Gd-enhanced MRA improves diagnostic performance compared with 2-D MRA