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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5780_Библиотеки_им_академика_М_И_Перельмана.pdf
17.4 Lung Parenchyma
Schmidt, Ultrasound © 2007 Thieme
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n
Pulmonary abscess (Fig. 607):
x
Variable echogenicity
x
Nonhomogeneous echo pattern
x
Occasional air echoes
x
Usually elliptical with smooth margins
x
Moving internal echoes
x
Accentuated walls
x
CDS: absence of vascularity
Fig. 607 Hypoechoic liquid mass in
the pleural space (A), air-fluid level on
the visceral pleura. Needle aspiration
yielded purulent fluid consistent with
an abscess. (LU = lung)
n
Pneumonia (Fig. 608):
x
Usually hypoechoic
x
Very nonhomogeneous texture (air bronchogram), depending on the extent of
consolidation
x
Irregular margins
x
Accentuated pleural walls
x
Variable shape
x
Occasionally accompanied by effusion
x
CDS: frequent increase in vascularity
17
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17
Thorax
Thorax
Thorax
Fig. 608 Pleural-wall lesion with
irregular margins, predominantly
hypoechoic with multiple high-amplitude air echoes as in pneumonia
n
Compression atelectasis (Fig. 609):
x
Hypoechoic
x
Homogeneous
x
Variable margins
x
Occasionally wedge-shaped
x
Size varies with respiratory excursions on real-time observation
x
Extent depends on the size of the pleural effusion
x
CDS: increased vascularity may be noted with proper equipment and technique
x
After percutaneous drainage: partial reinflation
409
17.4 Lung Parenchyma
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ab
Thorax
Thorax
Thorax
Fig. 609a, b a Scan demonstrating the right upper lobe (SL) with the echogenic
(aerated) bronchial tree and a significant effusion. b Following the percutaneous
aspiration of 2 L of fluid, the upper lobe is reinflated as in compression atelectasis
n
Obstructive atelectasis (Figs. 610 and 611):
x
Hypoechoic
x
Homogeneous
x
Smooth margins with lobar atelectasis
x
Variable shape
x
With complete atelectasis: homogeneous consolidation of the lung
x
CDS: increased vascularity may be noted with proper equipment and technique
x
In cases with pleural effusion: lung does not reinflate after drainage
x
Central mass is occasionally noted
Fig. 610 Lateral intercostal scan
shows complete atelectasis of the left
lung (AT) with a centrally located
bronchial carcinoma. S = spleen,
Fig. 611 Partial atelectasis of the left
upper lobe (AT). The central tumor (TU)
is visualized through the acoustic window
of the atelectasis (AT). C = heart, LU = lung
E = pleural effusion
n
Pulmonary infarction (Fig. 612):
x
Hypoechoic
x
Nonhomogeneous texture depending on the extent of consolidation
x
Irregular margins
x
Frequently wedge-shaped
x
Frequently multiple
x
CDS: absence of vascularity
x
410
Occasional small concomitant effusion
17.4 Lung Parenchyma
Schmidt, Ultrasound © 2007 Thieme
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Fig. 612 Wedge-shaped hypoechoic
lesion with irregular margins in the
periphery of the lung. Scintigraphy confirmed the infarction due to pulmonary
embolism. LU = lung, I = postinfarction
pneumonia
Evaluation and Further Testing
..............................................................................................................
n
Clinical features : frequently suggest the correct diagnosis, e.g.:
x
Pulmonary metastasis p primary tumor
x
Pulmonary abscess p fever
x
Pneumonia p coarse rales
x
Pulmonary infarction p deep lower-extremity venous thrombosis, etc.
n
Further testing :
x
Chest radiographs should always be obtained
x
FNAB to establish the diagnosis (e.g., lung tumors, pulmonary metastases, pulmonary abscess, pneumonia)
x
CT is advised for obstructive atelectasis, pneumonia, etc.
x
Catheter drainage is indicated for pulmonary abscess
x
Ultrasound follow-ups are often recommended
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Thorax
Thorax
Thorax
411
18.1 Examination
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18 Thyroid Gland
18.1 Examination
Scan Planes
..............................................................................................................
Thyroid Gland
Thyroid Gland
Thyroid Gland
n
Transverse scan of the neck
n
Oblique scan of the neck
n
Scanning tip: When using CDS, always use a window setting that covers the entire
thyroid lobe and use a consistent PRF setting such as 0.06 m/s.
Sonographic Anatomy and Normal Findings
..............................................................................................................
n
The thyroid gland is scanned from anterior to posterior in transverse section (contrasting with the “butterfly ” shape seen in anatomical textbooks and isotope
scans).
n
Sonographic anatomy (Figs. 613 and 614): The trachea can be seen just posterior
to the thyroid gland. The esophagus appears behind and to the left of the trachea
and posterior to the left thyroid lobe. The principal blood vessels in the neck run
posterolateral to the thyroid lobes.
Sternocleidomastoid
muscle
Longus colli
muscle
Vertebral column
Sternohyoid and
sternothyroid muscles
Internal
jugular vein
Common
carotid artery
Esophagus
Fig. 613 Schematic cross-section of the neck at the level of the thyroid gland
n
Normal findings (Fig. 615): The thyroid gland is covered by a capsule that clearly
delineates it from surrounding tissues. It has a grainy, homogeneous echo texture
and is hyperechoic to the surrounding muscles.
n
Normal dimensions: length 40–70 mm, width 10–30 mm, depth 10–20 mm
(per lobe). The isthmus is I 5 mm in width.
x
Total volume: I 25 mL in men, I 20 mL in women
x
Volumetry: length q width q depth q 0.5 for each thyroid lobe
412
18.1 Examination
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18
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Thyroid Gland
Thyroid Gland
Thyroid Gland
Fig. 614a, b Schematic
representation of the thyroid gland.
a Frontal view, b cross-sectional
view. L = length of gland, W = width
of gland, T = thickness of gland
TG
c
Fig. 615a–d Normal thyroid gland. Transverse scans of the right and left thyroid
lobes show a normal echogenic structure. A = common carotid artery, TG = right
and left lobes of thyroid gland, M = anterior and posterior neck muscles,
ES = cervical esophagus, TR = trachea
W
T
TG
d
ES
413
18.2 Diffuse Changes
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Aids to Examination
..............................................................................................................
n
Transducer: 5.0–7.5 MHz
n
Longitudinal scan in each maximum dimension, serial transverse scans while
moving the transducer over the skin (Fig.
n
Parathyroid glands can be defined by ultrasound only when they are enlarged
Thyroid Gland
Thyroid Gland
Thyroid Gland
(each is located posterior to the upper and lower poles of the thyroid gland).
n
Note: Pain during examination may indicate thyroiditis.
Overview and Classification of Findings
..............................................................................................................
n
The indication for ultrasonography of the thyroid gland may be a functional disor-
614).
der (hyper- or hypothyroidism) or a goiter. In many cases the findings are surprising and difficult to interpret. Particular attention will be given to those findings in
this chapter.
n
The differential diagnosis and functional aspects of specific thyroid disorders are
covered more fully in Section 6.14 (p. 179).
n
An ultrasound examination of the thyroid gland should always include an assessment of the parathyroid glands. Sometimes they must be included in the differential diagnosis of thyroid nodules. Parathyroid adenomas and hyperplasia appear as
hypoechoic nodules located posterosuperior or posteroinferior to the thyroid
gland (see p. 423).
n
Classification and overview: Thyroid changes that are observed on ultrasound
may be classified as diffuse or circumscribed:
x
Diffuse changes: may relate to the size or echogenicity of the gland; see
75.
Table
x
Circumscribed changes: range from anechoic (cyst) to intensely echogenic
(calcification); see Table
76.
18.2 Diffuse Changes
Overview (Table 75):
..............................................................................................................
Table 75.Diffuse changes in the thyroid gland
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Hypoechoic or normal echogenicity Hyperechoic
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Acute or subacute thyroiditis (p. 415)
Hashimoto thyroiditis (p. 415) Regressive fibrotic changes (p. 416)
Hyperthyroidism in Graves disease (p. 415)
Riedel thyroiditis (p. 416)
Malignant lymphoma (p. 416)
Diffuse parenchymatous goiter (p. 416)
Hypoechoic Changes
..............................................................................................................
n
Note: The echogenicity of the thyroid gland is always evaluated in relation to that
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy yyyyyyyyy
Diffuse colloid goiter (p. 416)
of the neck muscles. As a general rule, autoimmune thyroid disorders are all characterized by a diffuse decrease in echogenicity, although different entities can
often be distinguished based on differences in their echo patterns.
414
18.2 Diffuse Changes
Schmidt, Ultrasound © 2007 Thieme
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ab
Fig. 616a, b Subacute de Quervain thyroiditis. a B-mode image: patchy hypoechoic thyroid gland (TG; compare with muscle, M). b CDS: individual color spots.
The hypoechoic areas are largely devoid of vessels
n
Acute and subacute de Quervain thyroiditis (Fig. 616): This disease presents
clinically with acute malaise, local tenderness, inflammatory laboratory parameters, and frequent transient hyperthyroidism.
x
Large hypoechoic areas with ill-defined margins, interspersed among areas of
normal echogenicity
x
Overall impression: patchy hypoechoic pattern
x
CDS: increased vascularity. Sclerotic areas are hyperechoic and hypovascular
n
Chronic lymphocytic Hashimoto thyroiditis (Fig. 617): Patients present clinically
with asymptomatic hypothyroidism of early onset and a shrunken, fibrotic gland.
Other findings are an elevated ESR and high titers of thyroid peroxidase (TPO)
antibodies and thyroglobulin (Tg) antibodies (see also Fig.
x
Stippled or diffuse hypoechoic pattern
x
End stage marked by small, hypoechoic thyroid remnants
x
Scarred areas appear hyperechoic
x
CDS: marked increase in vascularity
n
Hyperthyroidism in Graves disease (Fig. 618; see also Figs. 243 and 244, p. 182):
Patients present clinically with a goiter and classic signs of hyperthyroidism:
weight loss, tachycardia, endocrine ophthalmopathy, and a thyroid bruit due to
increased vascularity.
245, p. 183).
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Thyroid Gland
Thyroid Gland
Thyroid Gland
Fig. 617 Chronic Hashimoto thyroiditis: uniformly hypoechoic thyroid gland
with a slight increase in vascularity
Fig. 618 Graves goiter. CDS: marked
hypervascularity (“vascular inferno”).
Median transverse scan of the neck.
TR = trachea
415
18.2 Diffuse Changes
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x
x
x
x
n
Riedel thyroiditis (synonym: chronic sclerosing thyroiditis): rare; presents clini-
Thyroid Gland
Thyroid Gland
Thyroid Gland
cally as a “stony-hard” goiter
x
x
n
Malignant lymphoma: invasive, confluent nodular mass of low echogenicity
n
Parenchymatous goiter: diffuse enlargement of the thyroid gland
x
x
Marked swelling, especially of the isthmus
Stippled or diffuse pattern of decreased echogenicity
CDS: increased vascularity (“vascular inferno” after Ralls)
Spectral analysis: increased flow velocity in the inferior thyroid artery, up to
125 cm/s.
Diffuse hypoechoic pattern caused by hyaline connective tissue
Smooth, distinct bulge in the contour of the gland
Normal echo pattern (Fig. 619a)
Requires differentiation from lipoma (Fig. 619c)
b
a
Fig. 619a–c Enlargement of the thyroid
gland (TG). a Parenchymatous goiter
(amiodarone therapy, hypothyroidism):
balloon-like enlargement of the thyroid
lobes with normal echogenicity (and
scant vascularity by CDS). b Diffuse
colloid goiter. Panoramic SieScape image
shows an enlarged, hyperechoic gland.
c Lipoma : isoechoic mass. Absence of
vascularity seen on CDS distinguishes the
c
lipoma from a parenchymatous goiter.
The patient had a long history of
hormone replacement therapy for a
goiter. M = muscle
Hyperechoic Changes
..............................................................................................................
n
Diffuse colloid goiter (Fig. 619b):
x
Clinical features : Histologically, the goiter is comprised chiefly of colloid-containing macrofollicles. Like diffuse parenchymatous goiter, it is classified as a
type of alimentary iodine-deficiency goiter. It is most prevalent in young people
who live in iodine-deficient regions. Diffuse colloid goiter has a relatively
coarse hyperechoic pattern (mostly macrofollicles), contrasting with the
unchanged echo pattern of a parenchymatous goiter (mostly normal-sized
follicles).
x
Sonographic features:
– Enlargement of the thyroid gland
– Coarse, hyperechoic pattern
n
Regressive fibrotic changes in the thyroid gland (Fig. 620):
x
Clinical features: may occur in a long-standing diffuse goiter or an irradiated
416
goiter. Fine, isoechoic nodules can be differentiated by their hypoechoic halo.
18.3 Circumscribed Changes
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ab
Fig. 620a, b Regressive changes in the thyroid gland. a Hyperechoic fibrotic
changes in the thyroid gland (TG) following irradiation (primary tumor: palatal
carcinoma). TR = trachea, JV = jugular vein. b Predominantly hyperechoic thyroid
gland with a nodular goiter and regressive fibrotic changes
Regressive changes marked by the formation of collagenous (i.e., echogenic)
connective tissue have a similar appearance to diffuse colloid goiter (usually
distinguishable by CDS, which demonstrates perinodal vessels).
x
Sonographic features:
– Hyperechoic goiter, frequently asymmetrical
– Nonhomogeneous internal echo pattern
– Long history of a goiter (or recurrent goiter) or previous radiotherapy to the
thyroid gland
18.3 Circumscribed Changes
Overview (Table 76):
..............................................................................................................
Table 76.Circumscribed changes in the thyroid gland
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Anechoic Hypoechoic or isoechoic Hyperechoic
yyyyyyyyyyyyyyyyyyyyyyyyyy
True cysts (p. 417)
Cystic transformation
(pseudocysts, p. 418)
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Adenomatous hyperplasia
(nodular goiter, p. 417)
Adenoma (p. 419) Hyperechoic adenoma
Colloid nodule (p. 419) Regressive changes in a
Hyaline connective tissue (p. 419) Calcifications (p. 422)
Abscess (p. 419)
Oncocytoma (p. 420)
Malignant tumor, metastasis (p. 420)
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy y
Hyperechoic adenomatous nodules (p. 422)
(p. 422)
nodular goiter (p. 422)
18
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Thyroid Gland
Thyroid Gland
Thyroid Gland
Anechoic Changes
..............................................................................................................
n
True (epithelium-lined) cysts: rare
x
Round and anechoic with smooth margins
x
Distal acoustic enhancement
417
18.3 Circumscribed Changes
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Thyroid Gland
Thyroid Gland
Thyroid Gland
ab
Fig. 621a, b Cystic transformation. a Cystic regression in a nodular goiter.
CDS: avascular nodular area. b Cystic transformation with coarse, floating echoes
correlating with a fresh intranodular hemorrhage (cursors)
n
Cystic transformation (“pseudocysts, ” Figs. 621 and 624): regressive changes in
goiters, adenomas or other tumors. Usually result from intralesional hemorrhage.
Percutaneous aspirate from a fresh lesion is bloody, later becoming brown (“chocolate cysts”) and finally yellowish (“yellow cyst ”). The differential diagnosis
includes lymph cysts and small colloidal cysts.
x
Classic cystic features as above, but more likely to have a noncircular shape
x
Hyperechoic internal structures (clots, septa):
– Fresh: flocculent internal echo pattern
– Old: completely anechoic
ab
Fig. 622a, b Adenomatous nodules (nodular goiter). a Transverse B-mode image:
hypoechoic nodule (N). TG = thyroid gland. b CDS in longitudinal section:
The nodules are surrounded by intense peripheral vascularity. M = anterior and
posterior neck muscles
Hypoechoic and Isoechoic Changes
..............................................................................................................
n
Adenomatous hyperplasia (adenomatous nodule, Fig. 622): nodular transforma-
tion of a long-standing goiter. With multiple nodules: nodular goiter. Histologic
examination shows a close-packed arrangement of small and large follicles.
418