ABC | Volume 112, Nº6, June 2019

Statement Vascular Ultrasound Statement from the Department of Cardiovascular Imaging of the Brazilian Society of Cardiology – 2019 Arq Bras Cardiol. 2019; 112(6):809-849 Figure 5 – (1) Diagram illustrating the placement of the cursor and the insonation angle. (A) Parallel to the jet in case of stenosis. (B) Parallel to the vessel. (2) Cursor and insonation angle toward the flow jet in case of stenosis (arrow). Table 6 – Quantification of internal carotid artery stenosis (Department of Cardiovascular Imaging of the Brazilian Society of Cardiology) % Anat Dist St (Nascet) PSV cm/s EDV cm/s PSV lC/ PSV CC PSV IC / EDV CC EDV IC / EDV CC < 50% < 140 < 40 < 2.0 < 8 < 2.6 50 to 59% 140 to 230 40 to 69 2.0 to 3.1 8 to 10 2.6 to 5.5 60 to 69% – 70 to 100 3.2 to 4.0 11 to 13 – 70 to 79% > 230 > 100 > 4.0 14 to 21 – 80 to 89% – > 140 – 22 to 29 > 5.5 > 90% > 400 – > 5.0 > 30 Subocclusion Variable – thin flow Variable – thin flow Variable – thin flow Variable – thin flow Variable – thin flow Occlusion Lack of flow Lack of flow Not applicable Not applicable Not applicable The colors represent, from left to right, the most relevant criteria according to the literature. CC: common carotid; IC: internal carotid; EDV: end-diastolic velocity; PSV: peak systolic velocity. 2.6. Ultrasound Evaluation of Vertebral Arteries The VUS evaluation of extracranial vertebral arteries contributes to the carotid study. It is divided into four segments: three extracranial and one intracranial (Figure 7). 27,28 2.6.1. Methodology to Perform the Examination The patient’s position is the same as that adopted for the carotid study. To evaluate the extracranial part of vertebral arteries, start the examination by the V2 segment. At this point, with the aid of color Doppler and small angulation movements, try to identify the artery (as well as its vein) and record the spectral curves, adapting the scale and insonation angle of the vessel. Past this point, the artery is displayed toward its origin. The V3 segment of the vertebral artery lies below the mastoid process of the temporal bone (anatomic mark for the study). This region presents the vessel end of the transverse foramen and its course around the mastoid process (also called “atlas loop” due to its anatomical relationship with this vertebral body). 3 The typical parameters expected are: Diameter: ranges from2 to 4mm. Caliber asymmetry among vertebral arteries is common (73% of cases), and the left one has a more dilated caliber in 50% of cases. 28,29 The normal standard with pulsed wave Doppler is waveforms with laminar antegrade flow of low-resistance, PSV between 20 and 60 cm/s in the V2 segment, and that can range from 30 to 100 cm/s in the origin of the vertebral artery. Due to the frequent diameter asymmetry, there is a considerable difference in PSV and resistance index (RI) among the normal vertebral arteries of an individual. 27 Vertebral artery hypoplasia is defined as a vessel diameter equal to or lower than 2.0 mm (or caliber asymmetry among vertebral arteries with ratio > 1:1.7). 28 819