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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 429
lumen wall. The lumen can, however, appear anechoic or
with a centrally located, moderately echogenic line or dot representing mucosa. The longus colli muscle extends laterally to
lie posterior to the common carotid artery.
◼ Neck muscles appear distinctively hypoechoic compared to
the thyroid gland. Anteriorly, the strap muscles (sternohyoid,
sternothyroid, omohyoid, and sternocleidomastoid) are easily
distinguished as is the longus colli muscle posteriorly.
• The long axis of the isthmus is situated horizontally and viewed
from a transverse scanning plane at the midline of the neck, just
anterior to the bright cartilaginous rings of the trachea.
• Branches of the inferior and superior thyroid arteries and veins
appear as 1 to 2 mm anechoic structures with thin, bright walls.
Color Doppler can be helpful in differentiating intra- and extrathyroidal vessels.
Parathyroid Glands
• By using newer high frequency transducers, normal parathyroid
glands are occasionally visualized sonographically, especially in
young children. When identified, they appear as a flat, hypoechoic
structure lying between the thyroid gland anteriorly and longus
colli muscle posteriorly.
Color Flow Doppler Characteristics
• Utilize color Doppler to differentiate vascular from nonvascular
structures.
• Adjust color Doppler parameters to detect normal or increased flow
in the thyroid gland.
• Color Doppler shows increased vascularity within and in the
periphery of autonomous functioning adenomas (a benign tumor
formed from glands) and thyroid cancer.
• Utilize color Doppler to follow the superior or inferior thyroid
arteries to locate parathyroid adenomas.
Normal Variants
Thyroid Gland
• Pyramidal lobe: Triangular-shaped, superior extension of the isth-
mus. Present in 15% to 30% of thyroid glands. Variable in size and
extends more often to the left side. Parenchyma appears the same
as the normal thyroid.
• Dilated follicles: Interspersed throughout the thyroid, they appear
as 1- to 3-mm cystic areas.
• Ectopic thyroid: Lingual thyroids account for 90% of ectopic
thyroids.
430 PART V Small Parts Scanning Protocols
Parathyroid Glands
• Ectopic parathyroid glands: Represent approximately 15% to
20% of the total.
• Variant parathyroid gland shapes: Elongated (11%), bi-lobed
(5%), or multi-lobed (1%).
Preparation
Patient Prep
• None.
Transducer
• “Small Parts” indicates a structure that is superficial or close to
the surface of the skin. In most cases, it requires a real-time, highfrequency transducer.
• 7.5 MHz to 10 MHz high resolution, real-time, linear transducer.
• According to the transducer and machine used, a water path or
standoff pad may be necessary.
• Doppler color flow imaging (low-flow filter, scale, and optimized
color gain).
Breathing Technique
• Normal respiration.
Patient Position
• The patient should be supine with the neck mildly hyperex-
tended and the head turned slightly away from the side
of interest.
• Place a sponge, pillow, or rolled towel under the patient’s shoulders
to maintain hyperextension of the neck.
Thyroid Gland Survey Steps
NOTE: Patient comfort and the amount of transducer pressure on the
skin surface is always an important consideration when scanning any
structure, but the significance is more acute with small part structures.
Generally, a lighter approach is recommended.
NOTE: The thyroid gland is small and can be seen in its entirety by some
transducers, but it is still evaluated by viewing the lobes individually.
CHAPTER 16 Thyroid and Parathyroid Glands Scanning Protocol 431
Lobes: Axial Survey Isthmus • Longitudinal Survey
Transverse Plane • Anterior Approach
1. Begin with the transducer perpendicular at the sternal notch.
Move the transducer slightly superior and toward the patient’s
right, lateral enough to view the right lobe from its medial to
lateral margins.
2. Keep the transducer perpendicular and scan superiorly through
and beyond the right lobe to the level of the mandible. Note the
isthmus medially.
3. Move the transducer inferiorly from the mandible back through
and beyond the inferior margin of the right lobe to the level of
the sternal notch.
432 PART V Small Parts Scanning Protocols
4. Move the transducer slightly superior and toward the patient’s
left, lateral enough to view the left lobe from its medial to lateral
margins.
5. Keep the transducer perpendicular and scan superiorly through
and beyond the right lobe to the level of the mandible. Note the
isthmus medially.
6. Move the transducer inferiorly from the mandible back through
and beyond the inferior margin of the left lobe to the level of the
sternal notch.
7. Move to the midline of the sternal notch and scan superiorly
until you scan through and beyond the isthmus.
CHAPTER 16 Thyroid and Parathyroid Glands Scanning Protocol 433
Lobes • Longitudinal Survey
Sagittal Plane • Anterior Approach
NOTE: Imaging the inferior portion of the lobes can be improved by
having the patient swallow. This raises the gland superiorly.
8. Begin with the transducer perpendicular at the midline of the
sternal notch. Move the transducer slightly superior and toward
the patient’s right, enough to view the right lobe from its superior to inferior margins.
9. Keep the transducer perpendicular and move toward the patient’s
right, scanning laterally through and beyond the right lobe.
10. Move back onto the right lobe and scan through and beyond the
lobe to the midline.
434 PART V Small Parts Scanning Protocols
11. From the midline move the transducer slightly toward the
patient’s left, enough to view the left lobe from its superior to
inferior margins.
12. Keep the transducer perpendicular and move toward the patient’s
left, scanning laterally through and beyond the left lobe.
13. Move back onto the left lobe and scan through and beyond to
the midline.
CHAPTER 16 Thyroid and Parathyroid Glands Scanning Protocol 435
Posterior
a
Sternocleidomastoid
Sternohyoid muscle
Sternocleidomastoid
colli muscle
Thyroid Gland Required Images
Thyroid • Right Lobe • Axial Images
Transverse Plane • Anterior Approach
1. Axial image of the INFERIOR right lobe.
Labeled: RT LOBE TRV INF
2. Axial image of the MID right lobe.
muscle
Right Left
Internal
jugular vein
Sternothyroid
muscle
Inferior
thyroid vessel
Common
carotid artery
muscle
Right Left
Anterior
Anterior
Sternohyoid muscle
Isthmus
Trache
Inferior
lobe
Longus
colli
muscle
Isthmus
Internal
jugular vein
Sternothyroid
muscle
Common
carotid artery
Longus
Labeled: RT LOBE TRV MID
Posterior
Trachea
Midlobe
436 PART V Small Parts Scanning Protocols
Posterior
Sternocleidomastoid
Sternohyoid muscle
3. Axial image of the SUPERIOR right lobe.
muscle
Right Left
Internal
jugular
vein
Common
carotid
artery
Longus
colli muscle
Anterior
Sternohyoid muscle
Trachea
Sternothyroid
muscle
Venous
structures
Superior
lobe
Labeled: RT LOBE TRV SUP
4. Longitudinal image of the ISTHMUS to include both the right
and left lobe attachments.
Anterior
Sternocleidomastoid
muscle
Sternocleido-
mastoid
muscle
Sterno-
thyroid
muscle
Right Left
Right common
carotid artery
colli muscle
Right
lobe
Longus
Labeled: ISTHMUS TRV
Isthmus
Trachea
Posterior
Left
lobe
Left common
carotid artery
Longus
colli muscle
Sternothyroid
muscle
CHAPTER 16 Thyroid and Parathyroid Glands Scanning Protocol 437
Posterior
rInferior
Platysma
Sternothyroid
Venous
Anterior
Posterior
rI
Thyroid • Right Lobe • Longitudinal Images
Sagittal Plane • Anterior Approach
5. Longitudinal image of the MEDIAL right lobe.
Skin
Thyroid
cartilage
Superio
Labeled: RT LOBE SAG MED
6. Longitudinal image of the LATERAL right lobe.
Skin
muscle
Medial
lobe
Anterior
Trachea
structures
muscle
Sternohyoid
muscle
Sternohyoid
muscle
Superio
Lateral
lobe
Sternothyroid
muscle
nferior
Labeled: RT LOBE SAG LAT
438 PART V Small Parts Scanning Protocols
Sternohyoid
Sternocleidomastoid
vessels
Longus
Posterior
Common
Omohyoid
Sternohyoid
Internal
Thyroid • Left Lobe • Axial Images
Transverse Plane • Anterior Approach
7. Axial image of the INFERIOR left lobe.
muscle
Right Left
Isthmus
Trachea
Sterno-
thyroid
muscle
Inferior
lobe
Inferior
thyroid
Labeled: LT LOBE TRV INF
8. Axial image of the MID left lobe.
muscle
Isthmus
Right Left
Sterno-
thyroid
muscle
Esophagus
Trachea
Anterior
Posterior
Anterior
Midlobe
muscle
Omohyoid
muscle
Internal
jugular
vein
Common
carotid
artery
colli
muscle
Esophagus
Sternocleidomastoid
muscle
muscle
jugular
vein
carotid
artery
Longus colli
muscle
Labeled: LT LOBE TRV MID