Contrast-Enhanced 3D MR Angiography and MDCT Angiography
Contrast-Enhanced 3D MR Angiography and MDCT Angiography
Objective: The objective of our study was to compare interobserver agreement for interpretations of contrast-enhanced 3D MR angiography and MDCT angiography in patients with peripheral arterial disease.
Subjects and Methods: Of 226 eligible patients, 69 were excluded. The remaining 157 consecutive patients were prospectively randomized to either MR angiography (n = 78) or MDCT angiography (n = 79). Two observers independently evaluated for arterial stenosis or occlusion on MR angiography (2,157 segments) and MDCT angiography (2,419 segments) using a 5-point ordinal scale. Vessel wall calcifications were noted. Interobserver agreement for each technique was evaluated with a weighted kappa (κw) statistic.
Results: Although interobserver agreement for both was excellent, the interobserver agreement for MR angiography (κw = 0.90; 95% confidence interval [CI], 0.890.92) was higher than that for MDCT angiography (κw = 0.85; 95% CI, 0.830.86) for reporting the degree of arterial stenosis or occlusion in all segments. For the different anatomic locations, the interobserver agreement for MR angiography versus MDCT angiography was as follows: aortoiliac (κw = 0.91 vs 0.84, respectively), femoropopliteal (κw = 0.91 vs 0.87), and crural (κw = 0.90 vs 0.83) segments. The interobserver agreement of MDCT angiography significantly decreased in the presence of calcifications but was still good for all anatomic locations. The lowest agreement was found for crural segments in the presence of calcifications (κw = 0.67). With MR angiography, there were 12 times more nondiagnostic segments than with MDCT angiography (81 vs 7, respectively).
Conclusion: Interpretations of MR angiography and MDCT angiography for peripheral arterial disease have an excellent interobserver agreement. MR angiography has a higher interobserver agreement than MDCT angiography, and the presence of calcified segments significantly decreases interobserver agreement for MDCT angiography.
Peripheral arterial disease is a local manifestation of atherosclerosis in the lower limb distal to the aortic bifurcation, which is a major problem in those who are 55 years old or older. In patients with peripheral arterial disease, the level, multiplicity, and severity of stenoses show significant variation that ultimately impacts clinical decision making. Digital subtraction angiography has traditionally been used for anatomic assessment of peripheral arterial disease. Digital subtraction angiography provides a precise road map for planning treatment, but owing to its invasiveness, digital subtraction angiography is associated with a risk of morbidity and mortality.
Both contrast-enhanced 3D MR angiography and MDCT angiography are increasingly used for noninvasive vascular imaging. MR angiography has gained widespread use for imaging peripheral arterial disease. Disadvantages of MR angiography include difficulty in depicting small vessels because of the limited spatial resolution and a tendency to overestimate the degree of stenosis because of signal intensity loss in tightly stenotic lesions.
The recently introduced MDCT scanners have substantially improved MDCT angiography for peripheral arterial disease. The use of MDCT technology has resulted in shorter acquisition time, increased volume coverage, lower dose of contrast medium, and improved spatial resolution. Results of several studies have shown that MDCT angiography is accurate for imaging peripheral arteries. The main disadvantages of MDCT angiography are the use of radiation, the use of potentially nephrotoxic iodinated contrast medium, the time-consuming 3D reconstruction techniques, and the difficulty in assessing arterial lumen stenosis in the presence of vessel wall calcifications.
In the evaluation of new diagnostic tests, the study of its interobserver agreements plays an important role. The accuracy of a test can never be perfect if assessments by different observers show significant variation. Furthermore, it is likely that poor interobserver agreement can cause variation in clinical decision making. Thus, apart from evaluating accuracy in comparison with a reference standard, it is important to evaluate reproducibility, including interobserver agreement for test Results.
The Purpose of this study was to compare the interobserver agreement for interpretations of contrast-enhanced 3D MR angiography and MDCT angiography in patients with peripheral arterial disease.
Objective: The objective of our study was to compare interobserver agreement for interpretations of contrast-enhanced 3D MR angiography and MDCT angiography in patients with peripheral arterial disease.
Subjects and Methods: Of 226 eligible patients, 69 were excluded. The remaining 157 consecutive patients were prospectively randomized to either MR angiography (n = 78) or MDCT angiography (n = 79). Two observers independently evaluated for arterial stenosis or occlusion on MR angiography (2,157 segments) and MDCT angiography (2,419 segments) using a 5-point ordinal scale. Vessel wall calcifications were noted. Interobserver agreement for each technique was evaluated with a weighted kappa (κw) statistic.
Results: Although interobserver agreement for both was excellent, the interobserver agreement for MR angiography (κw = 0.90; 95% confidence interval [CI], 0.890.92) was higher than that for MDCT angiography (κw = 0.85; 95% CI, 0.830.86) for reporting the degree of arterial stenosis or occlusion in all segments. For the different anatomic locations, the interobserver agreement for MR angiography versus MDCT angiography was as follows: aortoiliac (κw = 0.91 vs 0.84, respectively), femoropopliteal (κw = 0.91 vs 0.87), and crural (κw = 0.90 vs 0.83) segments. The interobserver agreement of MDCT angiography significantly decreased in the presence of calcifications but was still good for all anatomic locations. The lowest agreement was found for crural segments in the presence of calcifications (κw = 0.67). With MR angiography, there were 12 times more nondiagnostic segments than with MDCT angiography (81 vs 7, respectively).
Conclusion: Interpretations of MR angiography and MDCT angiography for peripheral arterial disease have an excellent interobserver agreement. MR angiography has a higher interobserver agreement than MDCT angiography, and the presence of calcified segments significantly decreases interobserver agreement for MDCT angiography.
Peripheral arterial disease is a local manifestation of atherosclerosis in the lower limb distal to the aortic bifurcation, which is a major problem in those who are 55 years old or older. In patients with peripheral arterial disease, the level, multiplicity, and severity of stenoses show significant variation that ultimately impacts clinical decision making. Digital subtraction angiography has traditionally been used for anatomic assessment of peripheral arterial disease. Digital subtraction angiography provides a precise road map for planning treatment, but owing to its invasiveness, digital subtraction angiography is associated with a risk of morbidity and mortality.
Both contrast-enhanced 3D MR angiography and MDCT angiography are increasingly used for noninvasive vascular imaging. MR angiography has gained widespread use for imaging peripheral arterial disease. Disadvantages of MR angiography include difficulty in depicting small vessels because of the limited spatial resolution and a tendency to overestimate the degree of stenosis because of signal intensity loss in tightly stenotic lesions.
The recently introduced MDCT scanners have substantially improved MDCT angiography for peripheral arterial disease. The use of MDCT technology has resulted in shorter acquisition time, increased volume coverage, lower dose of contrast medium, and improved spatial resolution. Results of several studies have shown that MDCT angiography is accurate for imaging peripheral arteries. The main disadvantages of MDCT angiography are the use of radiation, the use of potentially nephrotoxic iodinated contrast medium, the time-consuming 3D reconstruction techniques, and the difficulty in assessing arterial lumen stenosis in the presence of vessel wall calcifications.
In the evaluation of new diagnostic tests, the study of its interobserver agreements plays an important role. The accuracy of a test can never be perfect if assessments by different observers show significant variation. Furthermore, it is likely that poor interobserver agreement can cause variation in clinical decision making. Thus, apart from evaluating accuracy in comparison with a reference standard, it is important to evaluate reproducibility, including interobserver agreement for test Results.
The Purpose of this study was to compare the interobserver agreement for interpretations of contrast-enhanced 3D MR angiography and MDCT angiography in patients with peripheral arterial disease.
