Imaging Studies of the Femoral Artery: Overview of the Femoral Artery
Guest: Dr. Joseph Schoepf – Radiology
Host: Dr. Linda Austin – Psychiatry
Dr. Linda Austin: I’m Dr. Linda Austin. I’m interviewing Dr. Joseph Schoepf who is Associate Professor of Radiology and Internal Medicine and an expert in the area of heart and vascular imaging. Dr. Schoepf, one of the common studies that you perform is imaging of the femoral arteries. Just where are the femoral arteries?
Dr. Joseph Schoepf: Well, the femoral arteries are part of the arterial system that transports the blood down to the legs. A lot of patients out there have difficulties with the blood supply to their legs. This can start with very subtle symptoms, such as tiredness, tingling, or numbness of the leg, for example, which may or may not be an indicator for decreased blood supply to the lower extremities, the legs.
Dr. Linda Austin: Now, if a patient has those symptoms and they go see their family practice doctor, or internist, what physical exam procedures can that doctor do to determine, maybe as a rough screening, to see if there might be disease of the femoral arteries?
Dr. Joseph Schoepf: Well, there are very simple tests, such as simply feeling the pulse down in the legs to see if they are strong and equal. If that is the case, we already know that there is probably sufficient blood flow to the legs. However, if we suspect symptoms, we probably should go to the next layer in our diagnostic abilities, such as performing simple ultrasound procedures of the blood vessels supplying the legs. Typically, if we have a more central site of narrowing, or obstruction, one should be able to detect that with an ultrasound study.
If that is not conclusive, we can go to the next layer. A lot of patients with suspected peripheral vascular disease would have diagnostic angiography as the next step. But, fortunately, in this day and time, it is hardly necessary anymore. In most centers around the country, invasive diagnostic catheterizations are largely replaced by noninvasive tests, such as CT angiography or MR angiography. Both are wonderful noninvasive tests to accurately pinpoint areas that may be narrowed, or occluded, which can cause the kind of symptoms I was talking about.
Dr. Linda Austin: Now, why would you choose one over the other, CT versus MR angiography?
Dr. Joseph Schoepf: Both have their advantages and disadvantages. Computed tomography is based on x-rays which means that if you try and diagnose diseases of the peripheral vasculature, the vessels supplying the legs with blood, with a computed tomography scan, there would be radiation involved. The advantage of that technique is that it will allow you to accurately detect calcium, which is an important component of atherosclerotic disease. Calcium, typically, is a component that’s invisible to MR imaging. So, if that is of concern, CT may be the better test.
MR is based on a strong magnetic field, so it does not require any radiation to obtain images of the vasculature of the legs. However, it doesn’t always show you the association of calcium with atherosclerotic disease, and it’s sometimes difficult to determine the relationship of the vessels with the bones. So, particularly, if some surgical approach may be planned, an MR scan doesn’t always give you the information that you want. However, if a patient comes in with fresh signs of possible narrowings, or blockages, of the vessels supplying the legs with the blood, I would probably recommend an MR scan over a CT scan. Only if there is a particular question that pertains to calcium or planning a surgical procedure would I recommend a CT scan. So, in my book, an MRA, an MR angiography, of the lower extremity is probably the first choice if simple physical exams, or a simple test, such as ultrasound, do not suffice.
Dr. Linda Austin: Dr. Schoepf, thank you so much.
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