Vascular Malformations

Transcription

1 Vascular Malformations LTC Robert Shih Chief of Neuroradiology Walter Reed Medical Center Special thanks to LTC Alice Smith (retired)

2 Disclosures: None. This presentation reflects the personal views of the speaker and not of the US government or Department of Defense.

3 What imaging pattern is associated with higher risk of hemorrhage in a patient with dural arteriovenous fistula (davf)? 1. Pseudosubarachnoid sign 2. Pseudophlebitic pattern 3. Palm tree" appearance 4. Brush stroke" appearance

4 Regarding cavernous malformations, why might intravenous contrast be administered? 1. Evaluate the full extent of the lesion 2. Assess for presence of other cavernous malformations 3. Look for associated developmental venous anomaly 4. Assess arterial and venous supply T1+Gd Cavernous Malformations

5 Which imaging finding would be most characteristic of a capillary telangiectasia? 1. Mild to moderate mass effect 2. Faint stippled appearance on T1 post contrast 3. High signal on T1 weighted imaging 4. Presence of a hemosiderin rim

6 Objectives Describe the typical imaging appearance of the four intraaxial vascular malformations. Understand their clinical significance and the possible treatment options. List a few extraaxial vascular malformations.

7 Vascular Malformations Arteriovenous malformation (AVM) Classic AVM (intraaxial nidus) Pial arteriovenous fistula (pavf) Dural arteriovenous fistula (davf) Developmental venous anomaly (DVA) Cavernous malformation Capillary telangiectasia Shunt Mixed Malformation = Combo No Shunt

8 Teaching Point There are four intra-axial vascular malformations: AVM, cavernous malformation, developmental venous anomaly, and capillary telangiectasia.

9 Classic AVM 98% solitary Multiple AVMs usually syndromic: Hereditary hemorrhagic telangiectasia (HHT) Cerebrofacial arteriovenous metameric syndrome (CAMS)

10 Hereditary Hemorrhagic Telangiectasia An angiodysplastic disorder with AD inheritance May have multiple pial AVMs or AVFs

11 Intra/extracranial AVMs: CAMS Cerebrofacial Arteriovenous Metameric Syndrome

12 T2 AVM: Parenchymal Vascular Nidus

13 AVM: Clinical Significance Peak presentation age: year old Risk of hemorrhage: 2-4%/year ~50% present with symptoms of hemorrhage Seizures, headaches, focal neurologic deficits NECT

14 AVM Grading: Spetzler-Martin Size Small (<3cm) = 1 Medium (3-6 cm) = 2 Large (>6 cm) = 3 Location Noneloquent = 0 Eloquent = 1 Venous drainage Superficial = 0 Deep = 1

15 AVM Imaging: CT Intraaxial nidus of abnormal vessels Variable Hemorrhage Calcification: 25-30% Enhance post-contrast CTA: Enlarged feeding arteries and draining veins (AV shunting) CECT

16 AVM Imaging: CT NECT NECT Calcification Hemorrhage

17 AVM Imaging: MRI flow voids T2 FLAIR

18 AVM: Feeding Arteries & Draining Veins

19 AVM Imaging: Catheter Angiography Must image ICA, ECA, & vertebral circulation 27-32% of AVMs have dual arterial supply

20 AVM: Associated Abnormalities Flow-related aneurysm on feeding artery: 10-15% Intranidal aneurysm: >50% Vascular steal : Ischemia in adjacent brain

21 Increased Risk of Hemorrhage NECT Location (deep) Periventricular Basal ganglia Thalamus Arterial (aneurysm) Pedicle aneurysm Intranidal aneurysm Difficult to detect by MR Venous (stenosis or ectasia) Central venous drainage Obstruction of venous outflow Varix or venous pouch Small nidus! NECT

22 AVM: Treatment Surgery: Microvascular resection Radiation: Stereotactic radiosurgery Embolization: Liquid adhesive Observation: Risk of treatment vs disease

23 Teaching Point Classic or pial AVMs have an intraaxial (parenchymal or ventricular) nidus with enlarged feeding arteries and draining veins due to arteriovenous shunting.

24 Cavernous Malformation AKA: Cavernous angioma, cavernoma, cavernous hemangioma 2 types: Inherited: Multiple & bilateral Sporadic

25 Cavernous Malformation: Imaging T2

26 Cavernous Malformation: Imaging T2

27 Cavernous Malformation T2

28 Cavernous Malformation NECT T1+Gd

29 Cavernous Malformation NECT T2 T1

30 Cavernous Malformation Risk of hemorrhage: %/year More common in posterior fossa lesions In patients with prior hemorrhage annual rate of rehemorrhage 4.5% Treatment: Observation: Asymptomatic or inaccessible lesions Surgical excision Radiosurgery: Progressively symptomatic but surgically inaccessible T2

31 Cavernous Malformation T2 MPGR, GRE, SWI = T2* weighted sequences

32 Teaching Point Cavernous malformation is a no flow or angiographically occult lesion that may be associated with a developmental venous anomaly (prenatal venous obstruction).

33 Developmental Venous Anomaly (DVA)

34 Developmental Venous Anomaly Isolated or associated with cavernous malformation Hemorrhage unusual T1+Gd

35 DVA Imaging: CT Calcification & ischemia may occur in the region drained most likely due to chronic venous obstructive disease Rare for DVA to cause venous complications NECT CECT CECT

36 Images courtesy Jason Schroeder, MD DVA Imaging: MRI T2 SWI Surrounding T2 hyperintensity May occur in asymptomatic patients Acute edema from venous thrombosis Gliosis from chronic outflow obstruction T1+Gd

37 T1+Gd DVA

38 DVA: Treatment NONE! Removal may cause venous infarction T1+Gd

39 Teaching Point DVAs are benign incidental findings and are not to be confused with AVMs.

40 Capillary Telangiectasia

41 Capillary Telangiectasia T1 T2 T1+Gd

42 Brainstem Glioma

43 Capillary Telangiectasia T2 T1+C T2*

44 Capillary Telangiectasia T1+Gd E

45 Teaching Point Capillary telangiectasias are also benign incidental findings and are best seen on T2*-weighted or postgadolinium images.

46 Vascular Malformations Arteriovenous malformation (AVM) Classic AVM (intraaxial nidus) Pial arteriovenous fistula (pavf) Dural arteriovenous fistula (davf) Developmental venous anomaly (DVA) Cavernous malformation Capillary telangiectasia Shunt Mixed Malformation = Combo No Shunt

47 Arteriovenous Fistulas Distinguished from AVMs by presence of a direct high flow fistula between artery & vein Pial AVF (pavf) Dural AVF (davf) Cavernous carotid fistula (CCF) Vein of Galen malformation These are less common than intraaxial AVMs in the head (reverse is true in the spine).

48 davf Arteriovenous shunts within dura 10-15% of intracranial vascular malformations 2 types: Adult: Tiny vessels in wall of thrombosed dural venous sinus typically middle aged & older patients Usually acquired - trauma Infantile: Multiple high-flow AVshunts involving several thrombosed dural sinuses SSFSE Fetal MRI

49 AVF SSFSE T1

50 davf Grading: Cognard Classification Type I: In sinus wall, normal antegrade venous drainage Type II: In main sinus A: Reflux into sinus B: Reflux into cortical veins: 10-20% hemorrhage Type III: Direct cortical drainage 40% hemorrhage Type IV: Direct cortical drainage + venous ectasia 2/3 hemorrhage Type V: Spinal perimedullary venous drainage Progressive myelopathy

51 davf Grading: Lalwani et al Type I Type II Type III Type IV

52 davf Most common near skull base Transverse sinus most common Hemorrhage incidence: 2-4% per year Spontaneous closure rare Most are type I

53 CECT davf Imaging: CT

54 davf Imaging: MRI T2 T1+Gd!!! MRA: May be negative MRV: Occluded sinus, collateral flow

55 davf T2 T1 T1

56 davf: Conventional Angiography Multiple arterial feeders Dural/transosseous branches from ECA: most common Tentorial/dural branches from ICA or VA Dural sinus may be thrombosed Flow reversal in dural sinus/cortical veins risk of hemorrhage Tortuous engorged pial veins pseudophlebitic pattern

57 davf CECT Pseudophlebitic pattern

58 Teaching Point Dural AVFs are extra-axial lesions usually located in the wall of a venous sinus. Involvement of cortical veins is the major risk factor for hemorrhage.

59 Carotid Cavernous Fistula (CCF) The cavernous sinus is the second most common location for a dural AVF. This is also known as an indirect CCF. Fistula between arteries to the dural wall and the venous sinus. A hole in the cavernous internal carotid artery would cause a high flow AVF. This is also known as a direct CCF. Trauma or ruptured aneurysm.

60 Venous Drainage SOV Superficial Middle Cerebral V. Uncal v. Cerebellar SPS Pterygoid & basilar plexus IPS

61 CCF: CT Imaging Non-Contrast

62 T1 CCF: MRI

63 CCF: Venous arterialization T1+Gd T2

64 CCF: Arteriovenous Shunting SOV IMAX Indirect Courtesy Steven Goldstein, MD

65 CCF: Treatment Endovascular Surgical resection Observation: Indirect CCF (dural AVF) Cortical venous reflux is risk factor for future hemorrhage

66 Teaching Point Carotid-cavernous fistulas may be direct (hole in cavernous ICA) or indirect (davf in the dural wall of the cavernous sinus).

67 Vein of Galen Malformation (VOGM) Neonatal > infant presentation Rare adult presentation Classification: Choroidal: Multiple feeders from pericallosal, choroidal, & thalmoperforating arteries Mural: Few feeders from collicular or posterior choroidal arteries Drains MPV in 50% Falcine Sinus T1

68 VOGM is a type of AVF < 1% of cerebral vascular malformations CECT Venous Pouch

69 VOGM

70 VOG Malformation: Prenatal US

71 VOG SSFSE T2

72 VOGM: CT Findings CECT NCCT

73 VOGM: MR Imaging T2 T1

74 VOGM: Angiography Choroidal or mural Dural venous sinus anomalies Falcine sinus in 50% +/- absence or stenosis of other sinuses

75 VOGM: Angiography Choroidal

76 VOGM: Treatment Choroidal Medical therapy for congestive heart failure until 5 or 6 mo 5-6 mo: Transcatheter embolization Mural Transcatheter embolization performed later

77 CECT VOGM

78 Teaching Point Vein of Galen aneurysm is really a pial AVF (choroidal arteries to median prosencephalic vein).

79 Sinus Pericranii Communication between extracranial venous system & dural venous sinus Rare May be congenital or acquired

80 Sinus Pericranii CECT CT: Single/multiple bone defects Vascular enhancement Conventional angiogram: Seen during venous phase

81 T1+Gd MRV Sinus Pericranii

82 Sinus Pericranii Spontaneous regression rare Risk of hemorrhage Treatment Surgery Endovascular T1+Gd

83 Teaching Point Sinus pericranii is a scalp varix with an anomalous communication to the underlying dural venous sinus.

84 Vascular Malformations Intraaxial Arteriovenous malformation (AVM) Parenchymal or ventricular nidus Cavernous malformation Developmental venous anomaly (DVA) Capillary telangiectasia Extraaxial Arteriovenous fistula Pial on surface of brain (e.g. HHT or VOG) Dural in wall of venous sinus (e.g. transverse) Carotid-cavernous fistula Direct (hole in ICA) Indirect (dural AVF) Sinus pericranii

85 What imaging pattern is associated with higher risk of hemorrhage in a patient with dural arteriovenous fistula (davf)? 1. Pseudosubarachnoid sign 2. Pseudophlebitic pattern 3. Palm tree" appearance 4. Brush stroke" appearance

86 Regarding cavernous malformations, why might intravenous contrast be administered? 1. Evaluate the full extent of the lesion 2. Assess for presence of other cavernous malformations 3. Look for associated developmental venous anomaly 4. Assess arterial and venous supply T1+Gd Cavernous Malformations

87 Which imaging finding would be most characteristic of a capillary telangiectasia? 1. Mild to moderate mass effect 2. Faint stippled appearance on T1 post contrast 3. High signal on T1 weighted imaging 4. Presence of a hemosiderin rim

88 Objectives Describe the typical imaging appearance of the four intraaxial vascular malformations. Understand their clinical significance and the possible treatment options. List a few extraaxial vascular malformations.

89 The End Thank you!