Venous malformations show multiple anechoic spaces, but the flow in venous VMs may be so slow that it is difficult to perceive on Doppler. Lymphatic VMs are also composed of multiple anechoic spaces with cysts, which may contain fluid-fluid levels in the event there has been prior infection or hemorrhage but will not have Doppler signal. Venolymphatic malformations show a combination of these features. Fast-flow VM-AVMs and AVFs show a cluster of vessels without an associated solid tissue mass [36] with fast-flow on Doppler US. Variant 4: Child. Ultrasound features raise suspicion for vascular malformation. Next imaging study. If initial US imaging raises suspicion for the diagnosis of VM, further imaging is often helpful to visualize the entire extent of the lesion, assess for the presence of multiple lesions, and evaluate possible involvement of adjacent tissues and organs (including sensitive anatomic regions such as deep facial structures, the airway, orbits, and the spine). Arteriography Area of Interest Digital subtraction angiography provides an excellent definition of AVM anatomy, in particular the AVM nidus and the number and definition of feeding arteries and fistulas in fast-flow (arterial) lesions, with greater sensitivity than MRA [38]. Before an invasive procedure such as digital subtraction angiography is performed, it is best to have a narrowed differential diagnosis (usually requires prior MRI/MRA to suggest the diagnosis of a fast-flow VM). Diagnostic angiography may confirm the suspicion of a fast-flow VM if this remains in question following MRI/MRA but is typically reserved for symptomatic patients when simultaneous treatment is a leading consideration.
Soft Tissue Vascular Anomalies Vascular Malformations and Infantile Vascular Tumors Non CNS Child. Venous malformations show multiple anechoic spaces, but the flow in venous VMs may be so slow that it is difficult to perceive on Doppler. Lymphatic VMs are also composed of multiple anechoic spaces with cysts, which may contain fluid-fluid levels in the event there has been prior infection or hemorrhage but will not have Doppler signal. Venolymphatic malformations show a combination of these features. Fast-flow VM-AVMs and AVFs show a cluster of vessels without an associated solid tissue mass [36] with fast-flow on Doppler US. Variant 4: Child. Ultrasound features raise suspicion for vascular malformation. Next imaging study. If initial US imaging raises suspicion for the diagnosis of VM, further imaging is often helpful to visualize the entire extent of the lesion, assess for the presence of multiple lesions, and evaluate possible involvement of adjacent tissues and organs (including sensitive anatomic regions such as deep facial structures, the airway, orbits, and the spine). Arteriography Area of Interest Digital subtraction angiography provides an excellent definition of AVM anatomy, in particular the AVM nidus and the number and definition of feeding arteries and fistulas in fast-flow (arterial) lesions, with greater sensitivity than MRA [38]. Before an invasive procedure such as digital subtraction angiography is performed, it is best to have a narrowed differential diagnosis (usually requires prior MRI/MRA to suggest the diagnosis of a fast-flow VM). Diagnostic angiography may confirm the suspicion of a fast-flow VM if this remains in question following MRI/MRA but is typically reserved for symptomatic patients when simultaneous treatment is a leading consideration.