Tips for carotid ultrasound in the intensive care unit

Abstract

The ultrasonography of carotid arteries plays a key role in evaluating cerebrovascular disease. There are some useful considerations to perform it correctly in the intensive care unit, such as using different kind of transducer, Doppler mode optimization, and the correct interpretation of the findings.

Keywords: Carotid duplex; Carotid ultrasonography; POCUS; Point-of-care ultrasound.

Fig. 1

Use of a linear transducer in carotid Doppler ultrasound

Fig. 2

Visualization of carotid bifurcation in color Doppler mode with a linear transducer

Fig. 3

Use of a phased array transducer in carotid Doppler ultrasound

Fig. 4

Visualization of internal carotid artery in color Doppler mode with a phased array transducer

Fig. 5

Use of a transoral endocavitary transducer in carotid Doppler ultrasound

Fig. 6

Visualization of internal carotid artery in color Doppler mode with a transoral endocavitary transducer

Fig. 7

Color Doppler mode at the level of the common carotid artery with box sides forming a 90° angulation in relation to the vessel with poor-signal

Fig. 8

Optimization of the angle among box sides and the common carotid artery “manually tilting the vessel” and modifying angulation, thus obtaining good color Doppler signal

Fig. 9

Pulsed wave Doppler mode at the level of the common carotid artery with sample volume at 90° of the vessel under study, with incorrectly low peak systolic and tele-diastolic velocities

Fig. 10

Optimization of the angle between the sample volume and the direction of the common carotid artery “manually tilting the vessel”, modifying signal incidence (as tilted as possible) and rectifying the angle by aligning the dotted line with an arrow with the actual direction of the artery, always ensuring a 60° angle or less, thus obtaining actual peak systolic and tele-diastolic velocity values

Fig. 11

B-mode showing carotid bifurcation. The external carotid artery is more anterior and smaller in caliber with respect to the ascending portion of the internal carotid artery

Fig. 12

Low-resistance flow pattern typical of the internal carotid artery in pulsed wave Doppler mode

Fig. 13

High-resistance flow pattern typical of the external carotid artery in pulsed wave Doppler mode

Fig. 14

Filling defect at the level of the ascending portion of the right internal carotid artery associated with the presence of sonolucent plaque, producing a mosaic color pattern (aliasing) in color Doppler mode

Fig. 15

Pulsed wave Doppler mode at the level of aliasing area, showing increased peak systolic velocities consistent with stenosis > 50%

Fig. 16

Lack of color Doppler signal at the level of the ascending portion of the internal carotid artery (arrow) suggesting occlusion at that level

Fig. 17

Power Doppler mode shows the presence of a weak signal consistent with critical stenosis (arrow) at the level of the ascending portion of the internal carotid artery

Fig. 18

Color Doppler mode showing kinking in the ascending portion of the internal carotid artery

Fig. 19

Pulsed wave Doppler mode at the level of the right internal carotid artery with no flow evidence due to total occlusion, and left internal carotid artery with increased velocities due to compensatory hyperflow associated with collateral circulation at the level of the Circle of Willis

Fig. 20

Pulsed wave Doppler mode at the level of both internal carotid arteries, showing increased generalized velocities associated with hyperdynamic circulation

Fig. 21

A Continuous Doppler mode through the aortic valve in modified apical view of 5 chambers showing significant aortic regurgitation. B Pulsed wave Doppler mode at the level of the common carotid artery showing reversal of diastolic flow associated with aortic insufficiency