Diagnostic ultrasound ( PDFDrive )

CHAPTER 27 Peripheral Vessels 971
A
B
FIG. 27.10 Iliac Artery Stenosis With Tardus Parvus Waveform. (A) Tardus parvus waveform in the right common femoral artery indicates
severe upstream stenosis or occlusion. (B) Normal velocity biphasic waveform of the contralateral left common femoral artery indicates atherosclerotic
disease is in right common or external iliac artery, and not in the aorta (unilateral abnormal waveform).
A
B
FIG. 27.11 Supericial Femoral Artery (SFA) With >70% Stenosis. (A) Moderately severe stenosis in the SFA with a peak systolic velocity
(PSV) of 269 cm/sec. (B) At 4 cm upstream from the stenosis the PSV is 85.0 cm/sec, for a ratio exceeding 3 : 1, indicative of greater than 70%
stenosis.
and isolated and have a diameter reduction of greater than 50%.
In patients with endovascular intervention and stenting, Doppler
can monitor success of the procedure and survey for recurrent
stenosis at follow-up. In patients treated for critical limb ischemia,
Doppler follow-up should occur every 3 months for the irst
year. 20 Normal triphasic waveforms at the ankle help exclude
stenosis, but spectral Doppler is still performed even in the
absence of symptoms. For evaluation of stenosis within a stented
artery, the best Doppler criteria to characterize SFA in-stent
stenosis of 80% or greater include a combination of PSV above
275 cm/sec and PSV ratio (the ratio of the highest PSV within
the stent to the PSV in a disease-free arterial segment 3 cm
above the stented area) above 3.5. 21 In patients with stent repair
of SFA stenosis, Doppler and CT angiography have strong
agreement. 22
Aneurysm
An aneurysm occurs when weakness of the arterial layers allows
expansion of the arterial caliber beyond normal limits. Aneurysms
of the peripheral arteries are uncommon, but most are found in