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lead to pain, bleeding, and skin breakdown. In some cases,
they can result in high-output cardiac failure. Diagnosis
can be made by MRI or CT angiography. Biopsy should be
avoided because of the high risk of bleeding. Treatment
typically involves transcatheter embolization, with or
without additional modalities.
38,39
Digital subtraction
angiography is useful in precise demonstration of the
arterial feeders and venous drainage pathways for pre-
embolization planning.
AVMs are clinically classi
fi
ed by the Schobinger scale of
AVM severity (
Table 3
).
40
Grey-scale evaluation of AVMs
demonstrates a tangle of vessels with no associated mass.
Doppler evaluation shows arterial
fl
ow within the vessels,
with prominent draining vessels with high
fl
ow as well. MRI
re
fl
ects this high
fl
ow state by prominent
fl
ow-related
signal voids, as well as easier visualization of feeding and
draining vessels. MRA/MRV is frequently helpful in pre-
procedural planning for these lesions.
Pathology demonstrates beds of venules and arterioles,
intermixed with numerous larger-calibre arteries and thick-
walled veins.
Complex malformations
Lymphaticovenous malformation
Lymphaticovenous malformations (LVMs) are slow-
fl
ow
lesions that contain both lymphatic and venous ele-
ments.
41
In the authors
’
experience, these lesions are rare,
Figure 15
(a) Foot and lower leg of 24-year-old man with Parkes
e
Weber. Note thickened skin lesions as outlined by white arrows. Similar
changes are also noted in the anterior lower shin. (b) Lateral arteriogram of foot from popliteal injection. Note hypervascularity of AVM nidus
(white arrows) underneath the thickened skin lesions on photo (a). Note that the dorsalis pedis artery is the feeding artery (black arrow). The
posterior tibial artery (arrowhead) is marked for orientation purposes. (c) Selective arterial phase on dorsum of foot on lateral view. Note the
catheter in the dorsalis pedis artery (black arrow). The AVM nidus (white arrows) demonstrates early arterial enhancement with an early
draining vein (arrowhead). (d) Selective arterial phase on dorsum of foot on anteroposterior view. Note microcatheter in the distal part of the
feeding artery (black arrow) supplying the nidus of the AVM (white arrows). The draining vein is marked with the arrowhead.
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