Diagnostic ultrasound ( PDFDrive )

1658 PART V Pediatric Sonography
Clinically, a blush hyperemia and thrill or bruit may be present.
AVMs can enlarge acutely from increased blood low, obstruction,
or infection. An extensive lesion may cause congestive heart
failure. AVMs also are afected by hormones, oten increasing
in size at puberty and during pregnancy. 48 he most common
sites of AVMs in the head and neck include the cheek, followed
by the ear, nose, and forehead. 43 On gray-scale ultrasound, AVMs
demonstrate heterogeneity, with multiple hypoechoic channels
and absence of sot tissue mass. Doppler sonograms show a
high-low lesion with low-resistance arteries and arterialized
venous waveforms 47 (Fig. 48.51). Transcatheter embolization,
sclerotherapy, and surgical excision are the mainstays of
management. 48
In arteriovenous istulas (AVFs), there is direct communication
between the arteries and veins without an intervening tangle
of vessels; AVFs are frequently acquired during trauma. However,
both AVMs and AVFs can occur sporadically, in the setting of
hereditary hemorrhagic telangiectasia or capillary malformation–
arteriovenous malformation (CM-AVM) syndrome. 162
A combination of two or more simple vascular malformations
is classiied as a combined vascular malformation. Vascular
malformations are also categorized based on involvement of
major named vessels. It is important to recognize that both
vascular tumors and vascular malformations can be associated
with other anomalies and syndromes. 162
Other Congenital Lesions
Cervical aortic arch is a rare congenital anomaly in which the
arch is positioned high, above the clavicle, usually in the right
side of the neck. his developmental variant occurs because
of persistence of the embryonic third arch with regression of
the fourth. 170 hese patients are oten asymptomatic but can
have a pulsatile anechoic mass, dysphasia, and respiratory
symptoms. 43
Internal jugular phlebectasia is a rare congenital saccular
or fusiform dilation of the internal jugular vein. 43,171 he lesion
typically occurs on the right side with a history of asymptomatic
neck swelling, although uncommon complications such as
thrombosis and Horner syndrome have been reported. 172,173
Ultrasound demonstrates an echo-free, slow-low vessel on
color Doppler sonography that measures greater than 15 mm
in anterior-to-posterior dimension and increases in size with
Valsalva maneuver 171,172 (Fig. 48.52). Treatment is typically
conservative. 173
Iatrogenic Lesions
Color and duplex Doppler ultrasound are noninvasive techniques
that provide information about blood vessel patency, size, and
direction of blood low. 174-176 Vascular lines are typically placed
through the subclavian or jugular vein into the superior vena
cava. Gray-scale and color Doppler sonograms can demonstrate
arterial and venous stenosis, thrombosis, or pseudoaneurysms,
which can result from central line placement or prior extracorporeal
membrane oxygenation (ECMO) therapy 177 (Fig. 48.53).
Ultrasound guidance has also proved useful for insertion of
central venous and ECMO catheters to prevent morbidity related
to malposition. 178-180
Inlammatory Lesions
Lemierre syndrome is rare and typically occurs in young
adults, more commonly male, ater a primary oropharyngeal
infection. 181 It is hypothesized that thrombophlebitis of tonsillar
veins propagates into the internal jugular vein, resulting in
Fusobacterium necrophorum or streptococcal septicemia and septic
emboli, primarily to the lungs. 182,183 Ultrasound demonstrates
an engorged, noncompressible vein that may contain echogenic
thrombus. Color Doppler ultrasound can document absent
low and may show a lack of pulsation with Valsalva maneuver
(Fig. 48.54). Blood cultures and chest radiography or CT scan
secure the diagnosis so that appropriate antibiotic therapy can be
instituted. 184
Lymph Nodes
Lymph nodes consist of an outer cortex of lymphoid follicles
and hilum containing lymphatic sinus, connective tissue, and
blood vessels. Cervical lymph nodes, which number about 300,
are located along the lymphatic vessels in the neck. 185 A normal
infant lymph node measures less than 3 mm in diameter. 43 In
children, lymph nodes larger than 1 cm in maximum dimension
are considered enlarged. On ultrasound, a normal node is ovoid
and hypoechoic, with an echogenic hilum containing central
vascularity (Fig. 48.55). he normal length exceeds its width
by 2 : 1. 74
Lymph nodes can enlarge as a result of reactive hyperplasia,
infection, inlammation, or malignancy. 186 Cervical lymphadenopathy
is common and frequently a normal inding in
children. From 47% to 55% of children of all ages and 80%
to 90% of children aged 4 to 8 years have palpable reactive
hyperplastic lymph nodes not originating from infection or
systemic illness. Palpable lymph nodes in infants, however, are
not normal and should be evaluated further. Supraclavicular
lymphadenopathy and large nodes are concerning, associated
with high risk of malignancy and requiring FNA and/or
biopsy. 186-188
he diagnosis of lymphadenitis is oten clinical, and most
cases are uncomplicated; therefore most patients are treated
medically and require no additional imaging. If imaging is
performed, key features include location, extent of cellulitis,
myositis, presence of abscess, and vascular compromise. 144 With
ultrasound imaging, lymphadenitis demonstrates multiple
enlarged lymph nodes, normal in shape but with reduced
echogenicity and increased central and peripheral vascularity
74,144,189 (Fig. 48.56). With progressive enlargement of the nodes
and cellulitis, there is blurring of sot tissue planes, some septa
may stand out, and color Doppler imaging shows increased blood
low 45 (Fig. 48.57). When an abscess forms, the nodes coalesce,
central vascularity disappears, and a hypoechoic center, sometimes
with posterior enhancement, is present and surrounded by a
thick, hyperechoic, hypervascular irregular capsule (Fig. 48.58).
Pus-luid levels, luid movement on Doppler ultrasound, and
hyperechoic foci with comet-tail artifacts, signifying air, help
conirm the diagnosis. 74 In severe cases, adenitis may spread to
the deep cervical spaces such as retropharyngeal, parapharyngeal,
or submandibular space. 190 In rare instances, sinus tracts and