Related Experiment Videos
MR angiography of abdominal and peripheral arteries. Techniques and clinical applications
L Ekelund1, L Sjöqvist, K A Thuomas
1Department of Diagnostic Radiology, University Hospital, Linköping, Sweden.
Abstract:
This review article deals with MR angiography (MRA) of abdominal and peripheral arteries. Pulsatile flow, respiratory motion and peristalsis impose difficulties in imaging the vascular structures in the abdomen and the lower extremities. Development of new techniques, such as segmentation of the data acquisition, using specific acquisition windows in relation to a cardiac trigger, magnetization preparation of the tissue and phase-encoding re-ordering or sorting, have reduced the artifacts associated with abdominal and peripheral MRA. Clinical MR investigations of the arteries branching from the abdominal aorta such as the renal and mesenteric arteries and arteries in the lower extremities have revealed that severe stenoses or occlusions can be diagnosed accurately while the grading of less severe stenosis is more difficult. The phase-contrast method has been used to quantify blood flow and study the hemodynamics in abdominal and peripheral vessels. Quantitative flow information can be used to diagnose vascular disease and provides important physiological information. More prospective clinical studies, in which recently developed MRA techniques are compared with conventional angiography, are necessary before conclusive decisions can be made as to whether MRA may replace these methods.
Insights
Magnetic Resonance Angiography (MRA) improves imaging of abdominal and peripheral arteries by reducing motion artifacts. While effective for diagnosing severe blockages, further studies are needed to compare MRA with conventional angiography for less severe cases.
Area of Science:
- Radiology and Imaging Science
- Cardiovascular Imaging
Background:
- Abdominal and peripheral arteries present imaging challenges due to pulsatile flow, respiratory motion, and peristalsis.
- Artifacts in Magnetic Resonance Angiography (MRA) can complicate visualization of these vascular structures.
Purpose of the Study:
- To review advancements in MR angiography (MRA) techniques for abdominal and peripheral arteries.
- To assess the diagnostic accuracy of MRA for arterial stenoses and occlusions.
- To evaluate the role of phase-contrast MRA in quantifying blood flow and hemodynamics.
Main Methods:
- Review of novel MRA techniques including data segmentation, cardiac triggering, magnetization preparation, and phase-encoding reordering.
- Analysis of clinical MR investigations of abdominal aorta branches (renal, mesenteric) and lower extremity arteries.
- Application of phase-contrast methods for quantitative blood flow assessment.
Main Results:
- New MRA techniques significantly reduce artifacts in abdominal and peripheral vascular imaging.
- MRA accurately diagnoses severe arterial stenoses and occlusions but struggles with grading less severe stenosis.
- Phase-contrast MRA provides valuable quantitative flow and hemodynamic information for diagnosing vascular disease.
Conclusions:
- MRA techniques have advanced, improving visualization and diagnosis of significant arterial disease in the abdomen and periphery.
- Quantitative flow analysis using MRA offers important physiological insights.
- Further prospective comparative studies against conventional angiography are required to establish MRA as a replacement method.