Abstract:
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Purpose: To determine and compare interobserver agreement of three-dimensional contrast-enhanced magnetic resonance angiography (CE-MRA) and multi-detector computed tomographic angiography (MD-CTA) in patients with peripheral arterial disease.
Methods and Materials: Ninety-six consecutive patients with peripheral arterial disease were prospectively randomized to either CE-MRA (n = 45) or MD-CTA (n = 51). Two readers independently evaluated arterial stenosis on CE-MRA (1395 segments) and MD-CTA (1581 segments). Arterial stenosis was graded on a five-point ordinal scale: 0-19% stenosis, 20-49% stenosis, 50-74% stenosis, 75-99% stenosis, and occlusion. Furthermore, the readers recorded the presence of calcifications on MD-CTA and nondiagnostic segments on both tests. Interobserver agreement for each technique was determined by calculating Cohen's kappa (κ) statistic. Where more than two ordinal categories were evaluated a weighted kappa (κw) statistic was used.
Results: We found excellent interobserver agreement of CE-MRA (κw= 0.92) and MD-CTA (κw= 0.88) for reporting the degree of stenosis in all segments. For the different stations the interobserver agreement was: aortoiliac (κw= 0.93 vs. κw= 0.89 ), femoropopliteal (κw= 0.92 vs. κw= 0.91 ), and crural (κw= 0.92 vs. κw= 0.84), respectively. The difference in interobserver agreement was significant (P < .001) for the crural station only. CE-MRA depicted 62 nondiagnostic segments (59 segments by reader 1 and 35 segments by reader 2) which were mainly crural segments and mainly due to venous enhancement. MD-CTA depicted only four nondiagnostic segments. The interobserver agreement of MD-CTA decreased in the presence of calcifications. However, there was still excellent interobserver agreement for the aortoiliac (κw= 0.83) and femoropopliteal (κw= 0.87 )stations. The lowest agreement was found for MD-CTA of the crural segments in the presence of calcifications but it was still acceptable (κw= 0.66).
Conclusion: Interobserver agreement is excellent for both CE-MRA and MD- CTA for reporting the degree of stenosis in patients with peripheral arterial disease. Venous enhancement on CE-MRA complicates interpretation of crural arterial segments. Calcified segments on MD-CTA decreases the interobserver agreement.
Questions about this event email: r.ouwendijk@erasmusmc.nl
Ouwendijk MD, R,
Contrast-enhanced Three-dimensional MR Angiography and Multidetector CT Angiography of the Aortoiliac System and Lower Extremities Have an Excellent Interobserver Agreement. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3101522.html
