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Abstract
Introduction/purpose The characterization of cerebral arteriovenous malformation (AVM) hemodynamics is important in the evaluation and management of AVMs. Here, we measure flow volume rate, flow velocity, pulsatility index (PI), and resistance index (RI) in arterial feeders of AVMs using quantitative magnetic resonance angiography (QMRA).
Materials and methods Records of patients with cerebral AVMs evaluated at our institution between 2007–2014 and with flows obtained before treatment using QMRA were retrospectively reviewed. Flow volume rate and flow velocity were measured in primary arterial feeders (anterior cerebral artery, A2 segment; middle cerebral artery, M1 segment; posterior cerebral artery, P2 segment) and compared to their contralateral counterparts. PI = [(systolic - diastolic flow velocity)/mean flow velocity] and RI = [(systolic - diastolic flow velocity)/systolic flow velocity] were calculated for each feeder and compared to the normal contralateral vessel. The relationship between PI, RI and AVM clinical and angioarchitectural features was also assessed.
Results 72 patients with a total of 98 feeder arteries were included. Cohort characteristics are summarized in Table 1. Among all feeders, mean flow volume rate (332.3 vs. 121.6 mL/min, P < 0.001) and flow velocity (46.1 vs. 25.8 cm/s, P < 0.001) were significantly higher and mean pulsatility index (0.20 vs. 0.27, P < 0.001) and resistance index (0.18 vs. 0.23, P < 0.001) were significantly lower than in the normal contralateral vessels (Figure 1). Similar results were obtained among each feeder vessel type. There was no significant association of feeder vessel PI and RI with hemorrhagic presentation (P = 0.64,0.80, respectively), exclusive deep venous drainage (P = 0.75,0.11), venous stenosis (P = 0.42,0.70), single draining vein (P = 0.91, 0.90), or deep location (P = 0.32,0.78).
Conclusion PI and RI can be measured using QMRA and are significantly lower in AVM arterial feeders compared to normal vessels, thereby resulting in significantly higher flow volume rates and flow velocities in feeder vessels. Although we found no significant correlation between PI, RI, and AVM angioarchitectural characteristics thought to be associated with increased hemorrhage risk, future studies with larger sample sizes may better elucidate this relationship.
Patient and AVM characteristics
Comparison of mean pulsatility and resistance indices among all AVM feeders versus normal contralateral vessels
Disclosures S. Shakur: None. S. Amin-Hanjani: None. H. Mostafa: None. V. Aletich: None. F. Charbel: None. A. Alaraj: None.