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Contrast-enhanced magnetic resonance angiography in the evaluation of peripheral bypass grafts
1Department of Angiography and Interventional Radiology, University of Vienna, Austria.
Abstract:
The aim of this study was to determine the potential of contrast-enhanced magnetic resonance (MR) angiography in the evaluation of peripheral bypass grafts. Digital subtraction angiography (DSA) served as a standard of reference. Thirty-five patients with previous bypass graft surgery underwent DSA and contrast-enhanced MR angiography within 2 weeks. MR angiography was performed using a three-dimensional fast gradient-echo sequence after administration of gadopentetate dimeglumine. Every leg was divided into 11 segments and scored in five categories of stenosis. MR angiography findings were compared with those of DSA. A total of 38 bypass grafts and 454 segments in 27 patients were included in the evaluation. In 33 (87%) bypass grafts stenosis grading with both methods corresponded, and in 5 (13%) cases stenosis was overestimated on MR angiography. Agreement in detection of hemodynamically significant stenosis (stenosis =50%) was 94.7% with a sensitivity of 100% and a specificity of 91.3%. In 340 (83.0%) vascular segments there was conformity in graduation, in 69 (16.88%), there was a difference of one or more grades on MR angiograms. Forty-four segments (9.6%) were not assessable due to technical limitations. Contrast-enhanced MR angiography is an useful noninvasive tool in the detection of failing peripheral vascular bypass grafts.
Insights
Contrast-enhanced magnetic resonance (MR) angiography effectively evaluates peripheral bypass grafts, showing high agreement with digital subtraction angiography (DSA). This noninvasive tool is useful for detecting failing vascular grafts.
Area of Science:
- Vascular imaging
- Medical diagnostics
- Radiology
Background:
- Peripheral bypass grafts are crucial for limb salvage.
- Assessing graft patency and detecting stenosis is vital for patient outcomes.
- Digital subtraction angiography (DSA) is the current standard but is invasive.
Purpose of the Study:
- To evaluate the potential of contrast-enhanced MR angiography (CE-MRA) for assessing peripheral bypass grafts.
- To compare CE-MRA findings with DSA, the reference standard.
- To determine the diagnostic accuracy of CE-MRA in identifying stenosis in bypass grafts.
Main Methods:
- Thirty-five patients with prior bypass graft surgery underwent both DSA and CE-MRA.
- CE-MRA utilized a 3D fast gradient-echo sequence with gadopentetate dimeglumine.
- Grafts and vascular segments were analyzed for stenosis and compared between modalities.
Main Results:
- 38 bypass grafts and 454 segments were evaluated.
- 87% of grafts showed corresponding stenosis grading between CE-MRA and DSA.
- CE-MRA demonstrated 94.7% agreement for hemodynamically significant stenosis (≥50%), with 100% sensitivity and 91.3% specificity.
Conclusions:
- Contrast-enhanced MR angiography is a valuable noninvasive tool for evaluating peripheral bypass grafts.
- CE-MRA shows high accuracy in detecting significant stenosis and assessing graft status.
- This technique can aid in the early detection of failing peripheral vascular bypass grafts.