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PART 3 — PERIPHERAL ARTERIAL
SONOGRAPHIC EXAMINATION TECHNIQUES
The sonographic examination of a patient with nonatherosclerotic arterial disease is similar to that employed when evaluating patients for suspected atherosclerosis (refer to Chapter 9). The portion of the vascular system interrogated is determined by the presenting symptoms and the disease suspected. In some instances, a combination of direct duplex imag- ing techniques along with indirect physiologic testing is employed to fully characterize the disease. Specific examination details will be included within the dis- cussion of each disease entity. Basic ultrasound tech- niques are described in the following section.
DUPLEX ULTRASOUND TECHNIQUES
Generally, the grayscale image will be examined in both transverse and sagittal orientations to fully visu- alize any wall abnormalities or vessel defects. Images should be recorded from all major vessels examined. Additional images should be obtained from adjacent vessels when documenting wall abnormalities and should be compared to normal portions of vessels.
Spectral Doppler and color flow imaging tech- niques should be used to evaluate the vessels for flow disturbances and stenoses. Color can be quickly used to determine general flow patterns as well as to detect turbulent flow, increased flow, flow outside of a vessel, or the absence of flow. Spectral Doppler must be used to characterize the peak systolic veloc- ity (PSV) from each vessel examined. End-diastolic velocity (EDV) may also need to be recorded, par- ticularly if abnormally high or low resistance flow patterns are observed. In areas of suspected stenosis, PSV should be recorded before the area of interest, at the area of maximum PSV, and distal to this area. Poststenotic turbulence should be also documented.
VASCULAR ARTERITIS
Vascular arteritis is a phrase used to describe sev- eral inflammatory diseases that affect the blood ves- sels. The etiology of arteritis is unknown but often involves an immunologic condition. The inflamma- tory process of arteritis is associated with the media of the cell wall becoming infiltrated with a variety of white blood cells. Muscular and elastic portions of the wall are eroded and fibrosis develops. The end result is an overall weakening of the blood vessel and necrosis within the vessel wall.1,2
The symptoms of arteritis can often be similar to those symptoms encountered with atheroscle- rosis. When an arteritis involves extremity vessels
symptoms such as claudication or rest, pain can be present. Several types of arteritis can impact the up- per extremities. The most common upper extremity arterial pathology seen is proximal atherosclerotic subclavian artery disease. Typically these patients are referred to the vascular laboratory for asym- metrical blood pressures, dizziness, or syncope. If assessment demonstrates stenosis of the axillary or brachial artery segments, this finding is seldom due to atherosclerosis and may be more consistent with giant cell arteritis or Takayasu’s arteritis.
GIANT CELL ARTERITIS
Giant cell arteritis or temporal arteritis is an inflam- matory vasculitis seen in elderly patients.3 The aver- age age of onset is 70 years old and rarely occurs in people younger than 50 years of age. Caucasians and females are more prone to the disease than males or other races. Patients are frequently referred to the vascular laboratory because of asymmetrical upper extremity blood pressures.3 Patients may also typi- cally present with temporal headaches, tenderness over the superficial temporal artery (a branch of the external carotid artery), decreased pulse, or a cord- like structure over the superficial temporal artery. Other symptoms may include aching or stiffness in the neck, headaches, jaw claudication, and visual disturbances. A significant risk exists of optic nerve ischemia and blindness can occur in giant cell ar- teritis; hence, giant cell arteritis can be a medical emergency. The most common site for giant cell ar- teritis is in the superficial temporal artery but there can be involvement of multiple extracranial arteries and other arteries of the head and neck. Occasion- ally, arteries below the aortic arch are involved. The erythrocyte sedimentation rate is often elevated as well as another inflammatory marker, C-reactive pro- tein. The gold standard for diagnosis is a temporal artery biopsy showing mononuclear cells and giant cells infiltrating the area around the elastic lamina within the media of the cell wall.
Scanning Technique
The sonographic examination of a patient with sus- pected giant cell or temporal arteritis involves im- aging the region of the vascular system related to the presenting symptoms. If a patient presents with temporal pain and headaches, the temporal artery itself will be examined, usually in association with a complete carotid duplex ultrasound examination. The temporal artery is the smaller of two terminal branches of the external carotid artery. It begins be- hind the mandible, crosses the zygomatic process, then courses along the temporal bone. It continues