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CHAPTER 6 • CAROTID ARTERY DISEASE




                     To conf rm the diagnosis, a complete physical   study is crucial to evaluate the structural pathology
                 examination and neurological assessment is important,   and anatomy for the brain and carotid artery, and to guide
                 including the examination of heart rhythm, auscultation   treatment. A duplex ultrasound study (DUS), computed
                 for carotid bruits and heart murmur (to rule out cardiac   tomographic  angiography  (CTA)  and/or  magnetic
                 emboli), fundoscopic examination (for detecting retinal     resonance  angiography  (MRA)  are  recommended
                 embolization), together with a focused neurologic examination    methods for assessing the severity of extracranial carotid
                 (to associate with an ischemic territory). The National     stenoses (27).
                 Institute of Health Stroke Scale (NIHSS) may be applied        A DUS is normally the f rst-choice imaging modality
                 for quantif cation of the neurological def cit and speculate     for detecting, grading, and monitoring of extracranial
                 the outcome after ischemic stroke (25,26). Again, clinical   ICA stenoses. The key variables to determine the severity
                 f ndings have to be associated with vascular and brain     of carotid stenosis are the ICA peak systolic velocity
                 imaging in order to decide if a carotid stenosis is symptomatic.   (PSV), ICA end diastolic velocity (EDV), and the ratio
                     Carotid artery stenosis is def ned as ‘asymptomatic’     of PSV of the ICA to that of the CCA. As the stenosis
                 if no previous symptoms can be determined or if symptoms   at the bifurcation becomes more severe, the velocity
                 happened >6 months ago, and ‘symptomatic’ if linked   of the ICA velocity increases, which in turn, leads to
                 with symptoms in the previous 6 months.         a higher ICA/CCA PSV ratio (Fig 6-10). To date, there
                                                                 is a wide range and no internationally accepted standard
                 IMAGING STUDIES                                 for the gradation of carotid stenosis. The Society of

                                                                 Radiologists in Ultrasound (SRU) consensus criteria
                     In patients with stroke or TIA, an urgent imaging   are still widely used and recommend PSV cutoff values

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                  A                                             B
                                                                B
                  A













                                                                "
                                                                "

                  C                                             D
                                                                D
                  C














                                                                 ! !

                 Figure 6-10. Carotid duplex ultrasonography. A: Longitudinal image of the normal carotid artery and bifurcation into the internal and external
                 carotid arteries. B: B-mode imaging of the internal carotid artery showing the plaque morphology of the vessel wall as well as the area of
                 narrowing (arrows). C: Color Doppler in the same patient demonstrating the area of narrowing with increased (aliased) f ow denoted by
                 the blue/yellow pattern. D. B-mode imaging reveals severe turbulence f ow in the narrowing area. Doppler waveforms demonstrating increase
                 in peak systolic f ow velocity (369 cm/sec) and end-diastolic velocity (149 cm/sec).
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