The echocolor Doppler of the extracranial vessels is reliable when the professional who performs it is aware of the limitations of the examination in order to avoid misinterpretation.
The limits are both related to patient's anatomical/physical characteristics, and intrinsic to ultrasound.
In the first case, in particular, obesity should be taken into consideration: in fact, in obese patients the origin of the vertebral arteries and the origin of the right common carotid artery are visible with difficulty (or not visible). The presence of anemia, hyperthyroidism, and the recent physical activity may also overestimate the flow velocity.
In the second case the echocolor Doppler cannot explore the origin of the left common carotid and internal carotid arteries throughout their course. Moreover, in the presence of calcified plaque (with "shadow"), ultrasound cannot correctly evaluate the morphology of the plaque and the percentage of stenosis.
Other problems are related to the fact that ultrasound very often can certify only a range of percentages of stenosis (not a single percentage of stenosis) and the different measurement methods (ECST, NASCET) have caused some confusion in data interpretation with the risk of over/underestimation of the stenosis.
In this lesson the limits and the possible errors in the echocolor Doppler study of the extracranial vessels are presented.
Franco Accorsi, MD
Member of the Order of Physician of Bologna n° 6728
I am a specialist in Medical Angiology and I am based in Bologna, Italy. Until 2008 (voluntary resignation) I worked at Maggiore Hospital in Bologna as "Dirigente Medico" in the Department of Internal Medicine and as Angiologist in the Angiology Unit with a position of "Alta Professionalità" in "Vascular Ecography and Angiology".
I am currently working in Bologna as an independent professional in the areas of angiology and vascular diagnostics.
I have been a speaker at national and international courses/congress and I have taught duplex ultrasound method in GIUV and SIUMB courses at the Maggiore Hospital, Bologna and courses of echocolor Doppler of extracranial and intracranial arteries at the Stroke Unit of S. Maria Nuova Hospital, Reggio Emilia.