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Atlas of Human Body Ultrasound Scanning_ Methods and Diagnostic Applications ( PDFDrive ).pdf
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7  Vascular System Scanning

121

 

 

1\ Artery System

1.1\ Longitudinal Scanning

of the Common Carotid Artery

Fig. 7.1  Longitudinal section of the common carotid artery

1

RCCA

2 1

122

B. Su and Q. Yong

 

 

1.1.1\ Scanning Method

The subject takes a supine position with the head slightly stretched to make a full extension of the neck. The head holds the middle position or turns to the opposite side when one side of the common carotid artery is examined. The probe is put on the lateral or post-lateral neck, and a longitudinal scanning is performed from bottom to top.

1.1.2\ Sectional Structure

The longitudinal section of the common carotid artery and its bifurcation at the upper edge of the thyroid cartilage. The first layer of the wall is the hyperechoic line, which is an interface reflection between the fluid in the lumen and the arterial intima, usually thicker than the endometrium. The second layer (the hypoechoic line) is the carotid media. The third layer, the hyperechoic line, is the outer membrane.

1.1.3\ Measurement Methods

and Normal Value

Measuring carotid intima-media thickness (IMT) refers to the thickness between the first layer of the hyperechoic and the second layer of the hypoechoic, measuring the inner diameter from

one side of the endometrium to the offside wall of the endometrium. The IMT should be less than 0.09 cm, but the normal value is closely related to age, which can be said that the thickness of IMT will increase with age. A study found that at the age of 40, average thickness is 0.48 mm; according to formula (0.009 × age) +0.116, at the age of 100, IMT will be 1.02 mm. The normal value of the inner diameter is shown in Table 7.1.

Table 7.1  The normal value of the carotid artery inner diameter in different age groups

Age

CCA

ICA

ECA

20–40

6.6 ± 0.4

5.4 ± 0.5

4.3 ± 0.4

41–50

6.7 ± 0.5

5.6 ± 0.5

4.6 ± 0.5

 

 

 

 

51–60

6.9 ± 0.5

5.4 ± 0.6

4.4 ± 0.6

 

 

 

 

≥60

7.5 ± 0.9

6.0 ± 0.8

4.7 ± 0.4

1.1.4\ Clinical Significance

Showing the anatomic location, morphology, running, and situation of the wall and carotid artery lumen. IMT >0.14 cm is thought that the plaque have been formed. The most frequent site of plaque is carotid artery enlargement. IMT of the CCA can be an indicator of the degree of atherosclerosis.

7  Vascular System Scanning

123

 

 

1.2\ The Transverse Scanning

of the Common Carotid Artery

Fig. 7.2  The transverse section of the common carotid artery

RIJV

RCCA

124

B. Su and Q. Yong

 

 

1.2.1\ Scanning Method

The subject takes a supine position with the head slightly stretched to make a full extension of the neck. The head holds the middle position or turns to the opposite side when one side of the common carotid artery is examined. The probe is put on the lateral or post-lateral neck, and a longitudinal scanning is performed from bottom to top.

1.2.2\ Sectional Structure

The transverse section of the common carotid artery and jugular vein and of the bifurcation of the common carotid artery at the upper edge of the thyroid cartilage.

1.2.3\ Measurement Methods

Measuring carotid intima-media thickness (IMT) which refers to the thickness between the first

layer of the hyperechoic and the second layer of the hypoechoic. Measuring the inner diameter from one side of the endometrium to the opposite side of the wall endometrium.

1.2.4\ Clinical Significance

Showing the anatomic location, morphology, running, and situation of the wall and carotid artery lumen. Some researches said that cross scanning is more accurate than longitudinal scanning in the measurement of IMT. Measurement of the thickness of the plaque is best done by cross section. The degree of stenosis will be estimated in the cross section.