A great deal of interest has arisen in a non-invasive method of screening for lower extremity vascular disease. While duplex sonography and plethys-mography are quite reliable in identifying and localizing the general anatomic region involved, these tests cannot be used alone in planning en-dovascular procedures for the lower extremities. The specificities of these exams are diminished in the presence of multi-level disease.
MRA has recently emerged as an attractive alternative to the screening of patients with presumed lower extremity occlusive disease as well as planning possible endovascular treatment. It is important to realize the area of interest in these studies is usually over one meter in length to include both inflow and runoff.
Numerous studies have recently evaluated the ability of MRA to offer pre-procedure information as compared to duplex ultrasound. Leiner et al found MRA to be more effective for treatment planning as compared to duplex scanning .
One specific application where MRA offers benefits to conventional angiography is the presence of aorto-iliac occlusion. This is a clinical entity where conventional angiography can have technical difficulties in assessing both inflow and runoff due to access issues . MRA has been shown to accurately diagnose the occlusion and provide information regarding treatment planning .
The advantages of pre-procedure planning with MRA are numerous including an accurate depiction of aorto-iliac tortuosity, which can affect access route decision-making prior to infrain-guinal percutaneous revascularization. Being able to visualize the aorto-iliac segment can aid to determining whether the contralateral or ipsilateral femoral artery should be used for access (Fig. 6).
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