Figure 14-1
Hemorrhage due to AVM. Initial noncontrast CT (a) shows left temporal lobar hematoma with overlying subdural hemorrhage. CTA (b) shows a parenchymal nidus seen as a prominent tuft of vessels seen at the site of hematoma. CTA (c, d) shows prominent arterial feeders coming from the left MCA. DSA left internal carotid injection (early arterial phase) (e) shows AVM nidus supplied by left MCA. DSA (late arterial phase) (f) shows prominent draining vein showing early filling and coursing medially (Images courtesy of Dr. Ajay Malhotra)
Figure 14-2
Saccular, fusiform, and mycotic aneurysms. DSA images show a saccular right MCA bifurcation aneurysm (1a, 1b). Reformatted CTA images demonstrate fusiform vertebrobasilar aneurysm with dolichoectasia and atherosclerotic calcifications (2a, 2b). Multiple distal, small aneurysms at nonbranch points consistent with mycotic aneurysms (3a, 3b)
CT: most utilized screening tool
Conventional angiography superior to CTA and MRA
Conventional angiograms can identify involvement of deep thalamoperforators, which are considered to significantly increase surgical risk
Features on CT suggestive of AVM-related bleed
Cone-shaped lesion at periphery
Intralesional calcification
Unusual bleeding patterns with or without intraventricular extension
Headache: common symptom, nonspecific
Focal headaches can occur as a result of dilation of meningeal feeding arteries in AVMs that have significant meningeal supply
HA can be alleviated by embolization of these meningeal feeders
AVM Grading: Spetzler-Martin scale is the most widely used
Cumulative point score predicts morbidity and mortality associated with surgical treatment using (1) location, (2) drainage, and (3) size as criteria
Higher score associated with higher morbidity and mortality. Thus, AVMs that are of high risk may simply be observed
Location: eloquent area (1 point) or noneloquent area (0 point)
Eloquent: sensorimotor, language, visual cortex, hypothalamus, thalamus, brain stem, cerebellar nuclei
Venous drainage: deep (1 point) or superficial (0 point)
Size: <3 cm (1 point), 3–6 cm (2 points), > 6 cm (3 points)
Total score = grade
Grade 1: small, superficial, noneloquent, low surgical risk
Grade 4–5: large, deep, adjacent to eloquent tissue
Grade 6: only used to describe inoperable lesions
Treatment
Observation
Embolization: endovascular occlusion of vessels supplying AVM
Staged occlusion of deep or larger feeding vessels may decrease the risk of postoperative complications
Partial embolization of an AVM does NOT decrease future risk of hemorrhage
Surgical removal
Results in immediate elimination of risk of AVM hemorrhage
More often recommended in younger patients with low-risk AVMs, when patients are at risk for or have history of prior hemorrhage
In patients presenting with ICH, a controlled craniotomy with evacuation of the clot is performed, and resection of AVM is performed several weeks later electively
Radiosurgery (Gamma Knife)
Recommended in patients with smaller AVMs (3 cm or smaller) located in deep or eloquent brain tissue (speech/motor cortex, basal ganglia, thalamus) where surgical risk is high
Results in higher obliteration rates in smaller AVMs (80 % for <3 cm)
Notable Trials
Mohr et al. (2014): Randomized trial comparing outcomes in patients with unruptured brain arteriovenous malformations . Patients were randomized to medical management alone (symptomatic treatment as needed for neurological symptoms) versus interventional therapy (neurosurgery, embolization, stereotactic radiosurgery). The primary endpoint was death or symptomatic stroke. The trial found that the risk of death or stroke was significantly lower in the medical management group compared to the intervention group. Criticisms of the trial include the short duration follow-up that may not realize treatment potential, a potential selection bias (13 % of patients screened were selected) in enrolling less-severe AVM cases, not reflective of the hospital experience, and the heterogeneity of the endovascular procedures with regard to efficacy and complications (Mohr et al. 2014).
Intracranial Aneurysms
Prevalence estimated at 2–3 % of general population
See Figs. 14-2, 14-3 and 14-4 for imaging of subtypes
Figure 14-3
Right MCA-ruptured aneurysm, initial noncontrast CTs (a,b) show hyperdense subarachnoid hemorrhage in the basal cisterns which are effaces with more focal hematoma in the right sylvian fissure. CTA MPR-MIP images in axial (c), coronal (d), and sagittal (e) planes show a right MCA bifurcation aneurysm at the site of focal hematoma in the right sylvian fissure. DSA – right internal carotid injection (f, g) demonstrates aneurysm and vascular anatomy in relation to the neck of the aneurysm (Images courtesy of Dr. Ajay Malhotra)
Figure 14-4
ACOM aneurysm in a patient presenting with worst headache of life followed by loss of consciousness. Notice hemorrhage in the medial longitudinal fissure (left). Reconstructed images on CT angiography (right) show underlying aneurysm stemming from ACOM artery (red arrow)
Figure 14-5
Common locations of intracranial aneurysmsRelated posts:
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