Pearls Definitive treatment is only achieved with complete obliteration or excision of the iAVM. In cases of ruptured iAVMs, surgery is usually delayed several weeks if the patient is neurologically stable. The surgical goal must be complete iAVM resection, taking…
Pearls Aneurysms associated with iAVMs constitute a heterogeneous group with different risk profiles that must be taken into account when considering management options. In cases of hemorrhagic presentation, determining the source of hemorrhage (i.e., aneurysm vs iAVM) is crucial. Distal…
Pearls Patients with iAVMs typically present after hemorrhage, seizure, or the appearance of focal neurologic deficits. Comprehensive evaluation includes CT, MRI, MR angiography, CT angiography, and digital subtraction angiography, with additional studies as required and based on location. If possible,…
Pearls Asymptomatic iAVMs carry an ~ 2.2% annual risk for hemorrhage. If followed, asymptomatic AVMs that rupture carry a minimum 40% morbidity Genetic and environmental factors play a role in iAVM development. Risk factors for hemorrhage include intranidal or venous…
Pearls Presentation of iAVMs with seizures is more common in adult than in pediatric populations. AVMs in the frontal, temporal, and parietal lobes more commonly are associated with seizures. Size (> 3–4 cm), cortical location, long arterial feeders of middle…
Pearls Multimodality intervention for iAVM therapy complicates the specific surgical, endovascular, and radiosurgical risk-assessment systems. The most commonly applied classification for assessing surgical risk is the Spetzler-Martin grading system ( Table 8.1 ). Table 8.1 Surgical iAVM Classifications a Classification…
Pearls Abnormal vessels in the iAVM nidus allow direct transmission of high-pressure flow into venous low-pressure vessels, thereby increasing bleeding risk. Decreased resistance in abnormal iAVM vessels allows blood to flow into them more easily and “steal” blood flow from…
Pearls AVM-associated aneurysms are reported in 10%–20% of iAVM cases. Aneurysm size and number correlate with increasing patient age. Aneurysms are more commonly described in association with posterior fossa AVMs. The rupture rate of aneurysms associated with iAVMs is higher…
Pearls Common presentations of iAVMs include hemorrhage, seizure, headache, and focal neurological deficit. The risk of iAVM bleeding is increased with deep location, venous outflow obstruction, associated aneurysms, and deep venous drainage. Small iAVMs may have an increased risk for…
Pearls Advanced MRI techniques, including 4D flow, arterial spin labeling, diffusion, and susceptibility imaging, expand conventional anatomic assessments to physiologic evaluation. Understanding the underlying physics and properties of these sequences informs their complementary application in the assessment of iAVMs, including…