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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5782_Библиотеки_им_академика_М_И_Перельмана.pdf
CHAPTER 16 Thyroid and Parathyroid Glands Scanning Protocol 439
Posterior
Sternohyoid
Posterior
rI
Sternocleidomastoid
9. Axial image of the SUPERIOR left lobe.
Right Left
Trachea
Labeled: LT LOBE TRV SUP
Thyroid • Left Lobe • Longitudinal Images
Sagittal Plane • Anterior Approach
10. Longitudinal image of the MEDIAL left lobe.
Skin
muscle
Anterior
Superior
lobe
Longus
colli
muscle
Esophagus
Anterior
Sternocleidomastoid
muscle
Sternothyroid
muscle
Internal
jugular vein
Common
carotid artery
muscle
Sterno-
hyoid
muscle
Superio
Sternothyroid
muscle
Labeled: LT LOBE SAG MED
Medial
lobe
nferior
Longus colli
muscle
440 PART V Small Parts Scanning Protocols
Anterior
Posterior
rI
11. Longitudinal image of the LATERAL left lobe.
Sternohyoid muscle
Superio
Lateral lobe
Sternothyroid
muscle
nferior
Labeled: LT LOBE SAG LAT
Review Questions
Answers on page 630.
1. The thyroid gland is located
a. between the trachea and longus colli muscle.
b. lateral to the trachea and superior to the larynx.
c. in the lower, anterior portion of the neck, anterior to the trachea
and inferior to the larynx.
d. in the lower, anterior portion of the neck, posterior to the tra-
chea and superior to the larynx.
2. The normal thyroid gland generally appears as
a. medium to low-level echoes.
b. uniform echoes, hypoechoic relative to testes parenchyma.
c. uniform echoes, isosonic to liver parenchyma.
d. high-level echoes with coarse echo texture.
3. Normal parathyroid glands
a. are occasionally identified in young children.
b. appear isosonic to the thyroid gland.
c. are not sonographically appreciated.
d. appear as a bright rim posterior to the thyroid and anterior to
the longus colli muscle.
CHAPTER 16 Thyroid and Parathyroid Glands Scanning Protocol 441
4. The best way to image the inferior portion of the thyroid
lobes is to
a. use a stand-off pad.
b. have the patient swallow.
c. use a water path.
d. have the patient hold their breath.
5. The thyroid gland is connected in the middle by the
a. pyramidal lobe.
b. isthmus.
c. parathyroid glands.
d. recurrent laryngeal nerve.
6. The longus colli muscle is located
a. posterior to each thyroid lobe.
b. anterior to the thyroid gland.
c. between the trachea, esophagus, and sternothyroid muscle.
d. lateral to the internal jugular vein.
7. The best approach when scanning the thyroid gland is
a. lateral and coronal.
b. to compress the thyroid with the transducer to improve imaging.
c. to use a light touch with the transducer.
d. to use a stand-off pad.
8. The size of the thyroid gland is
a. influenced by body habitus.
b. larger in men.
c. the same size in men and women.
d. constant.
9. The best patient position to scan the thyroid gland is
a. sitting upright; chin relaxed.
b. supine; head to the side.
c. standing; head extremely hyperextended.
d. supine; neck mildly hyperextended.
10. The thyroid gland is
a. the master gland.
b. an exocrine gland.
c. a gastrointestinal accessory gland.
d. an endocrine gland.
11. The lobes of the thyroid gland are bordered laterally by the ______
and _______.
a. longus colli muscle, common carotid artery.
b. common carotid artery, internal jugular vein.
c. longus colli muscle, internal jugular vein.
d. common carotid artery, sternohyoid muscle.
442 PART V Small Parts Scanning Protocols
12. The average, normal adult thyroid gland is approximately _____cm
long, _____cm anteroposteriorly, and _____ cm at its greatest width.
a. 5; 3; 3
b. 4 to 6; 3; 3
c. 4 to 6; 1.3 to 1.8; 3
d. 7; 1.3 to 1.8; 3
13. The thyroid gland has two lateral _______ connected by the
_______.
a. lobes; strap muscles.
b. lobes; isthmus.
c. lobes; longus colli muscle.
d. parathyroid glands; isthmus.
14. The thyroid gland is located on the _______ side of the trachea.
a. posterior.
b. anterior.
c. right lateral.
d. left lateral.
15. The main function of thyroid hormones is to _____________.
a. increase metabolism.
b. regulate iodine levels.
c. stimulate the pituitary gland.
d. stimulate the hypothalamus.
16. The parathyroid glands lie between the ____aspect of the thyroid
gland and the ____.
a. posterior; longus colli muscle
b. anterior; longus colli muscle
c. posterior; trachea
d. anterior; trachea
CHAPTER 16 Thyroid and Parathyroid Glands Scanning Protocol 443
17. The long axis of the isthmus is situated _____ and viewed from a
____ scanning plane at the midline of the neck,
a. horizontally, coronal.
b. horizontally, transverse.
c. horizontal oblique, transverse oblique.
d. horizontally, sagittal.
18. The long sections of the lobes appear sandwiched between the
_____ anteriorly and ______ posteriorly.
a. strap muscles, trachea.
b. strap muscles, longus colli muscles.
c. strap muscles, common carotid artery.
d. longus colli muscles, strap muscles.
19. Each lobe is oriented vertically in the neck; therefore, the long axes
are visualized in sagittal scanning planes.
a. horizontally, coronal.
b. vertically, transverse.
c. horizontally, coronal.
d. vertically, sagittal.
20. The thyroid gland is ________ relative to the strap muscles.
a. hypoechoic.
b. isosonic.
c. anechoic.
d. hyperechoic.
Parenchymal tissue
Cooper's Ligament
Mammary duct
Subcutaneous fat
Breast Anatomy
CHAPTER 17
Breast Scanning Protocol
Betty Bates Tempkin
Key Words
Breast parenchyma
Breasts
Cooper’s ligaments
Exocrine glands
Lactation
Lactiferous ducts
Objectives
At the end of this chapter, you will be able to:
• Define the key words.
• Distinguish the sonographic appearance of the breast and the
terms used to describe it.
• List the transducer options for scanning the breast.
• List the suggested patient position (and options) when scanning
the breast.
• Explain the patient prep for a breast study.
• Name the survey steps and how to evaluate the entire breast.
• Distinguish the normal variants of the breast.
• Explain the order and exact locations to take representative
images of the breast/lesion.
• Answer the review questions at the end of the chapter.
Mammary layer
Parenchymal elements
Pectoralis major muscle
Retromammary layer
Stromal elements
Subcutaneous layer
Clinical Reasoning
• In most cases—for women under 30 and for lactating and pregnant
women—breast sonography has become the first phase of imaging
for evaluating palpable masses. Breast sonography, however, is not
recognized as a screening study for microcalcifications.
• Breast sonography is generally performed to determine the compo-
sition or characterization of a localized lesion(s) (that may or may
not be palpable) and to further evaluate mammographic and clinical
findings.
• Additional indications for breast sonography include ultrasound-
guided biopsies, treatment plans for radiation therapy, and evaluating
complications associated with breast implants.
• In some cases, whole-breast scanning may be recommended for
diffuse diseases, such as fibrocystic disease.
445
446 PART V Small Parts Scanning Protocols
Overview
Anatomy
• Each breast lies anterior to the sixth rib, pectoralis major, serratus,
and external oblique muscles. The second and third ribs form the
superior border of each breast and the seventh costal cartilage is
the inferior border. The medial border of each breast is the sternum
and laterally the breasts are bound by the margin of the axilla. The
most anterior aspect of the breast is attached to the skin.
• Breast tissue is supported by Cooper’s ligaments, suspensory liga-
ments that extend posteriorly from the deep muscle fascia, through
the breast, to the skin.
• The breast is comprised of:
• Parenchymal elements (lobes, ducts, and alveoli).
• Stromal elements (connective tissue and fat).
• The breast is described in terms of 3 layers:
1. Subcutaneous layer: Skin and subcutaneous fat lobules.
2. Mammary layer: 15 to 20 lobes that contain alveoli (multiple
glandular tissue lobules), and ducts that drain to the nipple; fat
lobules, and connective tissue.
3. Retromammary layer: Fat lobules and connective tissue.
Physiology
• The breasts or mammary glands are exocrine glands (release
secretions through ducts) whose primary function is lactation
(the secretion of milk) through lactiferous ducts (ducts in breast
parenchyma) following pregnancy.
Sonographic Appearance
• As shown in the image on the facing page, the 3 layers of the breast
are sonographically distinguishable; their normal appearance is
described as follows:
1. The subcutaneous layer is the most anterior layer bordered
anteriorly by the bright skin line and posteriorly by the mammary layer. In between, the subcutaneous fat lobules appear as
low-level echoes with bright margins.
2. The mammary layer is the middle layer of the breast that contains
glandular tissue or breast parenchyma. Typically it appears
hyperechoic compared to the subcutaneous and retromammary
layers due to its mixed parenchymal appearance depending on
the amount of fat that is present:
• The appearance with the presence of little fat is highly echogenic
due to the reflective appearance of the existing connective tissue
(collagen and fibrotic tissue).
CHAPTER 17 Breast Scanning Protocol 447
Pectoralis major
Retromammary
• When fat is present, the appearance is of areas of low-level echoes
(fat) mixed with areas of high echogenicity (connective tissue).
When visualized, the ducts appear as small anechoic branches
running throughout the layer.
3. The retromammary layer is generally hypoechoic relative to the
mammary layer and hyperechoic compared to the posterior border, the pectoralis major muscle (large chest muscle), which
has a low- to very low–level echo texture.
Skin line
Subcutaneous
layer
Mammary
layer
Retromammary
layer
muscle
• Although all the breast layers are influenced by the age of the
woman and the functional state of the breast, the mammary layer
shows the greatest changes sonographically.
• The sonographic appearance of the breast changes with age.
• The breasts of young women contain a high percentage of paren-
chymal elements and little fat. This causes the breast to be dense
and appear highly echogenic.
• Conversely, as seen in the following image, in older women the
subcutaneous and retromammary layers become more prominent when the mammary layer in the breast decreases in size as
parenchymal tissues atrophy and are replaced by fat tissue.
FAT LOBULES
Skin line
Subcutaneous
layer
Mammary
layer
layer
Pectoralis
major muscle
448 PART V Small Parts Scanning Protocols
Cooper’s ligament
• The next image demonstrates the thin, linear, bright appearance of
Cooper’s ligament. Notice how the ligament appears hyperechoic
relative to adjacent structures.
COOPER LIGAMENTS
Normal Variants
• Fatty breast: Increased fatty components throughout the breast
resulting from age, parity, and menopause. When fat is present,
the sonographic appearance is areas of low level echoes (fat) mixed
with areas of high echogenicity (connective tissue surrounding
mammary ducts).
• Fibrocystic breast: Commonly found in women of childbearing
age. Fibrous tissues and cystic areas occur throughout the breast,
as well as an increase in the amount of dense connective tissue,
which will cause the breast to appear highly echogenic.
Skin line
Subcutaneous
layer
Mammary
layer
Retromammary
layer
Pectoralis
major muscle
Preparation
Patient Prep
• None.
Transducer
• 10 to 18 MHz linear.
• Use compression sonography when assessing fibrocystic breasts.
Patient Position
Patient Position for Breast Lesion Scanning
• Position the patient to minimize the thickness of the portion of
the breast being evaluated.
Patient Position for Whole Breast Scanning
• Supine.
• Sitting erect.