Vascular Malformations Flashcards
Arteriovenous malformations (AVMs) are dilated arteries and veins with dysplastic vessels in which arterial blood flows directly into veins without any capillary bed and no intervening neural parenchyma. Which of the following statements are
correct regarding AVM?
● A. Risk of first-time hemorrhage is 1%/year
● B. Risk of recurrent ICH is 5%/year
● C. 5-year risk of first seizure is 8% for unruptured AVM
● D. 5-year risk of epilepsy after a first seizure is 58%
● E. All of the above
E. All of the above
What is the most common presentation of AVM which is about 58%?
● A. Hemorrhage
● B. Seizures
● C. Mass effect
● D. Ischemia
● E. Increased ICP
A. Hemorrhage
About 7% of patients with AVM have aneurysms. These aneurysms are classified into five types. Following statements regarding classification of these aneurysms are true except?
● A. Type 1 aneurysm is proximal on ipsilateral major artery feeding AVM
● B. Type 1A is aneurysm on proximal major artery related but contralateral to AVM
● C. Type 2 is aneurysm on distal superficial feeding artery
● D. Type 4 is aneurysm on artery related to AVM
● E. Type 3 is aneurysm on proximal or distal deep feeding artery
D. Type 4 is aneurysm on artery related to AVM
Characteristics of AVM on MRI include flow void on T1WI or T2WI within the AVM, feeding arteries, draining veins, and increased intensity on partial flip angle. What are the characteristics of AVM on angiography?
● A. Tangle of vessels
● B. Large feeding artery
● C. Large draining veins
● D. Draining veins are visualized in the same image as arteries
● E. All of the above
E. All of the above
Following statements are correct regarding Spetzler Martin AVM grading system except?
● A. Size of AVM less than 3 cm, 3 to 6 cm, and more than 6 cm are given 1, 2, and 3 scores, respectively
● B. Score 1 is given if AVM is on eloquent brain area and score 0 is given if it is on noneloquent area
● C. If pattern of venous drainage is deep then score is 1 and if it is superficial then score is 0
● D. Class A (S-M grades 1 and 2) is treated without surgery
● E. Class C (S-M grades 4 and 5) is treated without surgery
D. Class A (S-M grades 1 and 2) is treated without surgery
Which of the following statements is correct regarding pros and cons of surgery and radiation treatment for AVM?
● A. Surgery eliminates the risk of bleeding almost immediately while therapeutic response of stereotactic radiosurgery takes about 1 to 3 years during which time period risk of bleeding is about the same as natural history
● B. Surgery is an invasive procedure with high cost while stereotactic radiosurgery is a noninvasive procedure which is done on outpatient basis
● C. Seizure control improves in both surgery and radiotherapy but in the latter group it is subjected to reduction or obliteration of nidus
● D. Radiosurgery is limited to lesions less than or equal to 3 cm in size with obliteration rate of 70 to 80% and delayed side effects including radiation necrosis, brain edema, and cyst formation
● E. All of the above
E. All of the above
Following are the basic tenets of AVM surgery except?
● A. Exposure should be wide
● B. Feeding arteries are isolated and occluded before draining veins
● C. Excision of whole nidus is necessary to protect against rebleeding
● D. En passant vessels and adjacent arteries are identified and preserved
● E. Dissection is done directly on nidus of AVM while working in sulci and gyri whenever possible without damaging brain parenchyma
● F. In lesions that are low flow on angiography, preoperative embolization is considered
F. In lesions that are low flow on angiography, preoperative embolization is considered
For resected AVMs, follow-up is done with intraoperative or early postoperative angiogram to confirm complete removal of nidus, and residual nidus if present should be re-resected. If nidus is completely removed, then repeat catheter angiogram should be done at 1 and 5 years. Following radiosurgery, MRI/ MRA should be done at 6 months interval and if SRS-induced obliteration is demonstrated, then catheter angiogram should be done to confirm. What are the causes of delayed postoperative deterioration in case of AVM?
● A. Normal perfusion pressure breakthrough phenomenon, which is characterized by postoperative swelling or hemorrhage and it is thought to be due to loss of autoregulation
● B. Occlusive hyperemia: in the immediate postoperative period it is due to obstruction of normal venous outflow from the adjacent normal brain, while in a delayed presentation, it is due to delayed thrombosis of draining veins or dural sinus
● C. Rebleeding from a retained nidus of AVM
● D. Seizures
● E. All of the above
E. All of the above
Dural arteriovenous fistula is a vascular abnormality in which an arteriovenous shunt is contained within the leaflets of the dura mater, exclusively supplied by branches of the internal/external carotid or vertebral arteries. It presents with pulsatile tinnitus, occipital bruit, headache, and visual impairment with papilledema. Which of the following statements is incorrect regarding Cognard angiographic classification of dural AVMs?
● A. Type 1 is normal anterograde flow into the dural venous sinus and it is benign
● B. Type 2a is drainage into a sinus with retrograde flow within the sinus, 2b is drainage into a sinus with retrograde flow into cortical veins, and type 2a + b is drainage into a sinus with retrograde flow within the sinus and cortical veins
● C. Type 3 is direct drainage into a cortical vein without venous ectasia
● D. Type 4 is direct drainage into a cortical vein with venous ectasia
● E. Type 5 is direct drainage into spinal perimedullary veins in exclusion of all of the above
E. Type 5 is direct drainage into spinal perimedullary veins in exclusion of all of the above
Carotid cavernous fistula (CCF) is presented with orbital/retro-orbital pain, chemosis, pulsatile proptosis, ocular or cranial bruit, deterioration of visual acuity, diplopia, or pupillary dilatation. Which of the following is the type of CCF which is direct
high flow shunts between the internal carotid artery and cavernous sinus?
● A. Type A
● B. Type B
● C. Type C
● D. Type D
● E. All of the above
A. Type A
