Peripheral Vascular Disease Workup
What imaging studies are done in Peripheral Vascular Disease Workup?
@wanika The criterion standard for intraluminal obstruction has always been arteriography, though it is both potentially risky and often unobtainable in the emergency setting. The delay associated with obtaining arteriography in the setting of obvious limb ischemia can delay definitive treatment to deleterious effect. If time allows, arteriography can prove useful in discriminating thrombotic disease from embolic disease.
Doppler ultrasonographic studies are useful as primary noninvasive studies to determine flow status. Upper extremities are evaluated over the axillary, brachial, ulnar, and radial arteries. Lower extremities are evaluated over the femoral, popliteal, dorsalis pedis, and posterior tibial arteries. Note the presence of Doppler signal and the quality of the signal (ie, monophasic, biphasic, triphasic). The presence of distal flow does not exclude emboli or thrombi because collateral circulation may provide these findings.
Magnetic resonance imaging (MRI) may be of some clinical benefit by virtue of its high visual detail. Plaques are imaged easily, as is the difference between vessel wall and flowing blood. MRI also has the benefits of angiography, providing even higher detail and capable of replacing traditional arteriography. The utility of MRI is limited in the emergency setting, often because of the location of the device and the technical skill required to interpret the highly detailed images.
Computed tomography (CT) can be of use to the emergency physician in that it does not have the time and availability constraints that MRI does. Although noncontrast studies can be useful for imaging calcification and arteriosclerosis, contrast studies are most useful for imaging arterial insufficiency. Renal function should be confirmed before contrast administration; PVD often coexists with risk factors for contrast-induced renal failure. High-definition CT studies in patients who exhibit symptoms of PVD can be of benefit in guiding treatment decisions and modalities.
CT angiography (CTA) and magnetic resonance angiography (MRA) represent significant developments in axial imaging of PVD. Benefits of CTA include rapid noninvasive acquisition, wide availability, high spatial resolution, and the ability to generate isotropic datasets on 64-detector-row and higher CT scanners; drawbacks include the exposure to iodinated contrast and ionizing radiation. Benefits of MRA include high diagnostic accuracy and the avoidance of exposure to ionizing radiation; drawbacks include limited availability and increased cost.
Molecular imaging with radionuclide-based approaches may potentially provide a novel noninvasive assessment of biologic processes in PVD, such as angiogenesis and atherosclerosis.