Syndromes associated with multiple AVMs
HHT (hereditary hemorrhagic telangiectasia)
CAMA (cerebrofacial arteriovenous metameric syndrome)
Grading system for AVMs
Spetzler-Martin (higher grade, more risk of bleeding: over 2-4% risk of bleeding per year for AVMs)
Size (small <3, med 3-6, large>6 cm)
Location (non-eloquent, eloquent)
Venous drainage (superficial, deep)
Factors associated with increased risk of bleeding in AVMs
Location (periventricular, basal ganglia, thalami, post fossa)
Feeding artery or nidus aneurysm
Central venous outflow obstruction/stenosis
Deep venous drainage
Grading system for dural AVFs
Cognard Classification System - primary prognostic features is presence/degree of cortical venous drainage
Type I - No cortical venous drainage
Type IIA - Reflux into dural sinus, not cortical veins
Type IIB - Reflux into cortical veins (10-20% bleeding)
Type III - Direct cortical drainage - HIGH RISK OF BLEED
Type IV - Direct cortical drainage + venous ectasia - HIGH RISK OF BLEED
Type V - Spinal venous drainage
Most common location for dural AVF
Transverse sinus (at/near skull base)
Imaging findings in dural AVF
- multiple arterial feeders
- tortuous, engorged pial veins (“pseudophelbitic pattern”)
- thrombosed sinuses
- flow reversal in sinuses and cortical veins - MAJOR RISK FOR HEMORRHAGE DUE TO HIGH PRESSURES
Difference between direct versus indirect CCF
Direct - hole in the cavernous segment of the ICA with direct connection to cavernous sinus
Indirect - dural AVF in the wall of the cavernous sinus (dural ICA or ECA branches shunt to cavernous sinus)
Most common imaging finding of CCF
- reflux into superior ophthalmic vein (dilated), exoophthalmous
- extra vessels in the cavernous sinus region
Clinical and imaging features of Vein of Galen Malformation
Occurs in neonates/infants
HIGH OUTPUT CARDIAC FAILURE
AVF from the choroidal arteries to median prosencephalic vein (MPV)
Subtypes: Choroidal (many feeding vessels) versus mural (few feeding vessels)
Falcine sinus in 50%
Risk of bleeding of cavernoma
0.25-0.7% per year (much less than dAVF and AVM which are 2-4% per year); up to 5% if previous bleed
Imaging appearance of capillary telangiectasia
Faint, paint-brush like area of high T2/low T2* signal with minimal enhancement (incidental!!)
Sinus pericranii imaging findings
Communication between the extra-cranial venous system (i.e. scalp varies) and dural venous sinuses through single or multiple bony defects; need to be treated due to risk of hemorrhage
Which vascular lesions can be occult by vascular imaging
Cavernoma
Imaging appearance of cavernoma
Lobulated high T1/T2 signal, popcorn like, peripheral rim of hemosiderin; look for ass. DVA
DO NOT TOUCH VASCULAR LESIONS
1) DVA
2) Capillary telangiectasia
