Carotid Abnormalities Coils, Kinks and Tortuosity David Lorelli M.D., RVT, FACS Michigan Vascular Association Conference Saturday, October 20, 2012

Transcription

1 Carotid Abnormalities Coils, Kinks and Tortuosity David Lorelli M.D., RVT, FACS Michigan Vascular Association Conference Saturday, October 20, 2012 Page 1

2 Table of Contents Carotid Anatomy Carotid Duplex Carotid Duplex Criteria Normal Carotid Tortuous Carotid Limitations Helpful Scanning Techniques Page 2

3 Carotid Anatomy Subclavian Artery Common Carotid Artery (CCA) Bulb Internal Carotid Artery (ICA) External Carotid Artery (ECA) Vertebral Artery Page 3

4 Carotid Duplex Examination Duplex Ultrasound is the prefered method to investigate disease of the cervical carotid artery. Pulse-wave (PW) Doppler analysis has become the standard of care for categorization of ICA disease. A 60 degree angle or less should be used at all times, but as close to 60 as possible. Page 4

5 Carotid Protocol Subclavian Peak Systolic Velocity (PSV) and End Diastolic Velocity (EDV) CCA in transverse and longitudinal, in color and grey scale. Measure PSV and EDV in a longitudinal view at proximal, mid and distal CCA. Bifurcation in transverse using color and grey scale. Page 5

6 Carotid Protocol ICA in longitudinal showing color and grey scale. Measure PSV and EDV at proximal, mid and distal ICA. ECA in longitudual view showing color and grey scale. Measure PSV and EDV. Vertebral Artery, show color and doppler measuring PSV and EDV. Report direction of flow. Page 6

7 Standard Criteria MILD 0-39% Diameter Reduction: The presence of flow separation, there will be mild homogenous or heterogenous plaque present. The ICA peak systolic velocity is <110 cm/sec. May include minimal to mild spectral broadening. MODERATE 40-59% Diameter Reduction: Visible plaque is noted with an increase peak systolic velocity of <170 cm/sec. Increased spectral broadening is present. Page 7

8 Standard Criteria SEVERE 60-79% Diameter Reduction: Visible plaque is noted with an increase peak systolic velocity of >170 cm/sec and end diastolic velocity >40 cm/sec. Increased spectral broadening is present. CRITICAL 80-99% Diameter Reduction: An end diastolic velocity of >100 cm/sec will be present in a critical stenosis and peak systolic velocity is >250 cm/sec. Page 8

9 Standard Criteria OCCLUSION Visible plaque is noted throughout the ICA. No Doppler or color flow is seen within the vessel. Page 9

10 Normal Carotid Examination PSV <110 cm/s, EDV < 40cm/s. Open spectral window. ICA/CCA ratio <1.8 Straight ICA Page 10

11 Normal Carotid Examination Correct anatomical position, Angle toward the face for ECA. Angle laterally for ICA. Pictures in color and grey scale. Page 11

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15 Carotid Abnormalities Not all carotid artery exams are straightforward. Kinks, coils and tortuous vessels are common findings. Page 15

16 Carotid Abnormalities The incidence of these abnormalities in literature varies from 10% to 58%. May be developmental or acquired. More common in females >60 years old. Page 16

17 Incidence Study 1(Houston): 1438 patients 46% had an abnormality Tortuosity 35% Coil 6% Kink 5% Bilateral involvement 28-53%. Page 17

18 Incidence Study 2 (Turkey): 345 Patients 25% had abnormality Tortuosity 38% Coil 6% Kink 56% Bilateral involvement 48%. Page 18

19 Carotid Abnormalities Tortuous vessels are known to hinder the accuracy of the ultrasound evaluation. Correct angle and cursor alignment are critical to accurate velocity calculations. Page 19

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21 Limitations Elongating the vessel due to tortuosity Correct angle and cursor alignment within a tortuous vessel Shadowing caused by calcific plaque A patient with a thick neck Deep vessels Page 21

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23 Helpful Scanning Techniques Use multiple scanning planes. Anterior, medial and posterior. This can help eliminate shadowing or elongate the vessel better. If you are having a hard time elongating the vessel, go to a transverse view, then back into a longitudinal view to make sure you are lined up correctly. Change the angle of the color box to show better flow within the vessels. Page 23

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25 Helpful Scanning Techniques Heel-toe the probe to help get a better angle for PW doppler measurements. For deep vessels or a short neck try using a 4 MHz probe. Make sure to note on your worksheet if an angle besides 60 degrees is used, as well as, if there are any variations in the exam. For example: Carotid tortuosity, vessels diving deep, calcific shadowing limiting views ect. Page 25

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