Magnetic resonance angiography for the evaluation of lower extremity arterial disease - A meta-analysis

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.