Classification and ultrasound findings of vascular anomalies in pediatric age: the essential

Fig. 14
Venous malformation in 5-year-old boy. Spectral analysis 
shows a low-velocity flow with non-modulated spectrum
Fig. 15
Macrocystic lymphatic malformation in 1-month-old boy. 
Sonogram shows multicystic mass in the thoracic subcutaneous tis-
sue. The cystic spaces are anechoic and separated by septa
Fig. 16
Macrocystic lymphatic malformation in 13-month-old boy. 
Sonogram shows multicystic mass in the neck subcutaneous tissue. 
The cystic spaces are hyperechoic from hemorrhage. A fluid-debris 
level is seen within a cyst (arrow)

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21
Journal of Ultrasound (2019) 22:13–25 
1 3
cysts may be present. This aspect is due to the presence of 
numerous cysts that are too small to be displayed with probe 
resolution [
53
, 
54
].
On the color Doppler examination, the malformation is 
a slow flow lesion. Vascular signals are generally absent. In 
some cases, it is possible to identify arterial vessels confined 
in the larger septa. At the spectral examination, the arte-
rial flows show medium–low velocities and, above all, high 
resistance indices (Fig. 
17
). This aspect distinguishes them 
from hemangiomas where arterial resistance is low [
14
].
Arteriovenous malformation
Arteriovenous malformations consist of an abnormal net-
work of arterial and venous vessels with scarce or absent 
presence of capillaries.
They are high-flow lesions and are often in differen-
tial diagnosis with hemangiomas. The clinical evolution, 
from quiescent lesion to hemorrhage and heart failure, is 
described by the Schobinger classification.
1
On ultrasound examination, the arteriovenous malforma-
tions can have a very diversified appearance—from a con-
glomerate of moderate-sized vessels that determine a lesion 
that can be detected in soft tissues [
55
], up to a tangle of 
vessels that do not determine a real “mass effect” and are 
therefore poorly identifiable at the B-mode exam and can 
only be highlighted with the color Doppler exam [
14
]. One 
element to consider is the presence of adipose tissue around 
the arteriovenous malformation due to a fibroadipose pro-
liferation [
34
] that may result in a thin hyperechoic rim that 
delimits the lesion (Fig. 
18
).
At the color Doppler examination, the malformation is a 
high flow lesion. There are numerous vessels showing “high 
vascular density” with multidirectional flow. The spectral 
Doppler analysis shows arterial vessels with high-velocity 
flow and low resistive index (RI) (Fig. 
19
). Compared to 
hemangiomas, the venous vessels have a higher average 
velocity of flow, with an “arterialized” wave for the trans-
mission of the systolic pulse to the venous bed due to the 
lack of the capillary network [
1
, 
7
, 
14
, 
39
] (Fig. 
20
).