Narrowing of the blood vessels to the legs can cause a variety of symptoms including cramping during walking (claudication), pain in the legs with rest (rest pain), or non-healing wounds or ulcers of the legs and feet. People at risk include smokers, diabetics, patients with high cholesterol, or people with strong family history for vascular disease.
Medical work-up must consider or eliminate other common causes of leg symptoms. This can usually be done accurately through a combination of medical history, physical exam and noninvasive vascular studies that include blood pressure measurements of the arms and legs (ABI’s).
Once vascular disease is identified as the cause, and the symptoms are felt to be sufficient to warrant treatment, catheter angiography is performed. This time proven method is an accurate gold standard for diagnosis. It also allows efficient, and effective treatment of some abnormalities during the same procedure (angioplasty). During angioplasty, a balloon is placed through the catheter, expanding the narrowing in the blood vessel. A supportive strut, or stent is often then placed. Long term success of such treatment is excellent in the vessels of the pelvis (iliacs) or upper thighs. Narrowings lower in the leg are often candidates for surgical bypass.
Because the contrast dye used during catheter angiography can worsen kidney function, patients with known kidney dysfunction are candidates for MR angiography (MRA). This has a particular role in diabetics with a combination of limb threatening ischemia (for example a non healing foot ulcer) and renal dysfunction. MRA has the advantage of requiring only an I.V. injection of a kidney safe contrast agent (gadolinium). The state of the art Siemens Symphony 1.5 Tesla MR scanner at St. Mary’s Hospital operated by Turville Bay MRI Centers utilizes a dedicated vascular coil, moving table technique and high resolution methods to produce high quality images.
As the image quality of MRA is now excellent, patients may be selected for catheter angiography based on their likelihood of having iliac disease based on noninvasive testing. Catheter angiography is preferred in these patients since curative angioplasty can be performed at the same time as the catheter angiogram. The remainder of patients who may be potential surgical candidates based on noninvasive testing may be better candidates for MRA. Patients with renal dysfunction are also excellent candidates for MRA, thereby avoiding the kidney toxicity of iodine based contrast.
Newer MR techniques and contrast agents on the horizon will even further advance the quality of these studies in the near future.