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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5802_Библиотеки_им_академика_М_И_Перельмана.pdf
Gastrointestinal tract
116
FURTHER READING
Dietrich CF. Esophagus, stomach, duodenum. In: Endoscopic
Ultrasound: An Introductory Manual and Atlas. Stuttgart:
Thieme, 2011: Chapter 13.
Gill KR, Ghabril MS, Jamil LH, Al-Haddad M, Gross SA, Achem
SR, Woodward TA, Wallace MB, Raimondo M, Hemminger LL,
Wolfsen HC. Variation in Barrett’s esophageal wall thickness:
Is it associated with histology or segment length? J Clin
Gastroenterol. 2010; 44:411– 415.
Shorvon PJ, Lees WR, Frost RA, Cotton PB. Upper gastrointestinal
endoscopic ultrasonography in gastroenterology. Br J Radiol.
1987; 60:429–438.
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Gastrointestinal tract
118
Gastrointestinal tract wall
(transabdominal ultrasound)
PREPARATION
None (reference values are applicable regardless of fasting state).
POSITION
Supine.
TRANSDUCER
7.0–12.0 MHz linear transducer.
METHOD
Bowel wall thickness may be measured before and after ingestion
of 480 ml of water. Measurements should be made only on images
obtained in transverse sections. In the nondistended state, bowel segments demonstrate a target conguration. The thickness of the bowel
wall is measured from the edge of the high-reective core representing the intraluminal gas and mucus, to the low-reective outer border
representing the bowel wall. In the distended state (following ingestion
of water), the lumen is uid lled. Distension is considered adequate
when the luminal diameter is greater than 8 cm for the stomach, 3
cm for the small bowel, and 5 cm for the large bowel. Measurements
should be made from the low-reective intraluminal uid to the interface representing the serosa.
APPEARANCE
The gastrointestinal (GI) tract has a layered appearance on ultrasound
as described previously, and these ve layers are evident when using
frequencies of 5 MHz or more. Although it has been shown that thickness of the bowel wall depends on the amount of distension, patient
weight, and patient age, pathological thickening should be suspected
when it measures more than 2 mm (except in gastric antrum, duodenum, and rectum).
MEASUREMENT
GI wall tract thickness is dependent on transducer frequency, patient
weight, and patient age.
Gastrointestinal tract wall (transabdominal ultrasound)
Normal transverse colon (between
cursors) with no fecal residue
present.
119
Transverse image not at an absolute right angle (layers 1 and 5 not visualized),
demonstrating layer 2, deep mucosa; layer 3, submucosa; and layer 4, muscularis propria.
Gastrointestinal tract
120
GI tract wall thickness (mm) according to transducer frequency
Location Frequency
8 MHz 12 MHz
Gastric antrum 3.1 ± 0.8 2.9 ± 0.8
Duodenum 1.6 ± 0.3 1.6 ± 0.3
Jejunum 0.9 ± 0.2 0.9 ± 0.2
Ileum 1.2 ± 0.3 1.1 ± 0.3
Colon 1.0 ± 0.2 1.0 ± 0.3
Sigmoid colon 1.2 ± 0.3 1.2 ± 0.3
Rectum 2.1 ± 0.5
(4 MHz transducer)
FURTHER READING
Fleischer AC, Muhletaler CA, James AE Jr. Sonographic assessment
of the bowel wall. AJR Am J Roentgenol. 1981; 136:887–891.
Nylund K, Hausken T, Odegaard S, Eide GE, Gilja OH.
Gastrointestinal wall thickness measured with transabdominal
ultrasonography and its relationship to demographic factors in
healthy subjects. Ultraschall Med. 2012; 33:E225–232.
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Gastrointestinal tract
122
Anal endosonography
PREPARATION
None.
POSITION
Left lateral position. Females should be examined prone due to the
symmetry of the anterior perineal structures in this position.
TRANSDUCER
A high-frequency (7–10 MHz) rotating rectal transducer is used, which
provides a 360° image. A hard sonolucent plastic cone covers the transducer and is lled with degassed water for acoustic coupling. The cone
is covered with a condom with ultrasound gel applied to both surfaces.
METHOD
Serial images are obtained on slow withdrawal of the transducer down
the anal canal. Images are typically taken at the upper, mid, and lower
anal canal.
APPEARANCE
The normal anal canal is composed of ve distinct layers: mucosa, submucosa, internal anal sphincter, intersphincteric plane, and external
anal sphincter.
Mucosa: This low-reective layer is immediately adjacent to the transducer and is continuous with the rectal mucosa.
Submucosa: This high-reective layer lies between the mucosa and the
internal anal sphincter, becoming progressively thicker and denser caudally.
Internal anal sphincter: The smooth muscle of the internal sphincter is
seen as a homogeneous low reective circular band > 2–3 mm in width,
extending caudally to a level just proximal to the anal verge. The thickness should be measured at the 3 o’clock or 9 o’clock positions.
Intersphincteric: This is a narrow high-reective band between the two
sphincter planes.
External anal sphincter (EAS): The striated muscle of the external anal
sphincter has mixed reectivity and a linear pattern giving a “streaky”
appearance. The EAS can be traced from the puborectalis component
of the levator ani muscle to its cutaneous termination. The EAS is con-
Anal endosonography
sistent in appearance for both sexes posterolaterally. However, anteriorly, in females, the muscle is decient in the immediate region of the
perineal body and vagina. In males, the sphincter tapers anteriorly into
two arcs that meet in the midline.
123
View taken at the mid anal canal level demonstrating the internal sphincter (measuring
3mm) and the striated appearance of the external sphincter.
MEASUREMENTS
Average thickness (mm)
Female Male
Internal sphincter (increases with age*) 1.8–3.8 1.9–3.4
External sphincter 4.0–7.7 6.1–8.6
Longitudinal muscle 2.5–2.9 2.3–2.9
*0.38 mm every 10 years
Gastrointestinal tract
124
FURTHER READING
Abdool Z, Sultan AH, Thakar R. Ultrasound imaging of the anal
sphincter complex: A review. Br J Radiol. 2012; 85:865–75.
Beets-Tan RG, Morren GL, Beets GL, Kessels AG, el Naggar K,
Lemaire E, Baeten CG, van Engelshoven JM. Measurement of
anal sphincter muscles: Endoanal US, endoanal MR imaging,
or phased-array MR imaging? A study with healthy volunteers.
Radiology. 2001; 220:81–89.
Law PJ, Bartram CI. Anal endosonography: Technique and normal
anatomy. Gastrointest Radiol. 1989; 14:349–353.
Sultan AH, Kamm MA, Hudson CN, Nicholls JR, Bartram CI.
Endosonography of the anal sphincters: Normal anatomy and
comparison with manometry. Clin Radiol. 1994; 49:368–374.
SUPERFICIAL
6
STRUCTURES
Keshthra Satchithananda and
PaulS.Sidhu
Parathyroid glands 126
Submandibular salivary glands 128
Parotid salivary glands 130
Thyroid gland 132
Lymph nodes in the neck 136
Orbits (extraocular muscles) 140
Orbits (optic nerve) 142