Analysis of Mean Transit Time of Contrast Medium in Ruptured and Unruptured Arteriovenous Malformations

Abstract

Background and Purpose-To clarify hemodynamic risk factors for hemorrhage in arteriovenous malformations (AVMs), the mean transit time (MTT) of feeding arteries and draining veins in AVMs with and without hemorrhage was measured and analyzed. Methods-Morphological features such as the number and diameter of draining and feeding vessels and the AVM nidus volume were evaluated in 30 patients with supratentorial AVMs. The MTT of feeding arteries and draining veins was measured with the use of time-density curves obtained by digital subtraction angiography. The correlation between hemorrhage and morphology and hemorrhage and MTT was analyzed statistically. Results-The nidus volume was not significantly different between hemorrhagic and nonhemorrhagic AVMs. However, between ruptured and unruptured AVMs there was a significant difference in the mean number of draining veins (1.5Ϯ0.69 versus 2.3Ϯ0.50; Pϭ0.006), the MTT of the feeding artery (1.10Ϯ0.24 versus 1.62Ϯ0.55; Pϭ0.03), and the ratio of the MTT of the draining to the feeding vessels (1.71Ϯ0.43 versus 1.05Ϯ0.07; PϽ0.001). Conclusions-A high ratio of the MTT of draining veins to feeding arteries suggests disequilibrium between nidal inflow and outflow. The consequent increased pressure in the draining vein may contribute to the development of AVM hemorrhage.

Evaluation of 4D Vascular Flow and Tissue Perfusion in Cerebral Arteriovenous Malformations: Influence of Spetzler-Martin Grade, Clinical Presentation, and AVM Risk Factors

“…The intraclass correlation coefficient (0.00 -0.20, poor; 0.21-0.40, fair; 0.41-0.60, moderate; 0.61-0.80, good; and 0.81-1.00, excellent) was used to evaluate the interobserver agreement for perfusion measurements, and perfusion ratios were compared in the 3 ROIs (2-tailed paired t test). In addition, correlation analysis was performed between the SMG and AVM hemodynamics (Spearman correlation), between the AVM nidal volume calculated by V ϭ /6 ϫ a ϫ b ϫ c (a, b, c are 3D nidal diameters measured by experienced neuroradiologists on the basis of conventional DSA) 15 and AVM hemodynamics (Pearson correlation), and between AVM flow parameters and perfusion ratios (Pearson correlation). Multiple regression analysis (stepwise) was performed to identify the potential association of AVM flow or perfusion parameters with clinical presentation and risk factors.…”

Hemodynamic Quantification in Brain Arteriovenous Malformations With Time-Resolved Spin-Labeled Magnetic Resonance Angiography

“…This is allowed by the high temporal resolution, <70 ms, of 4D-SL-MRA sequence. Moreover, as suggested in previous reports, 2,11 hemodynamic quantification could be related to the clinical presentation because a low draining-vein-to-feeder-artery TTP ratio was associated with the high rupture risk and hemorrhagic groups. This lower TTP ratio, <2.0 in all cases, may reflect higher velocities and exposure to higher vascular pressure 12 within the nidus in patients with previous hemorrhage or known angioarchitectural bleeding risk factor.…”

Persistent Hemodynamic Changes in Ruptured Brain Arteriovenous Malformations

“…However, the results of these studies are contradictory. Some studies identified an elevated flow in feeding arteries, 35 whereas other studies found a reduced flow. 22,36 Our finding of a prolonged transit time is in accordance with disequilibrium of faster inflow, whereas outflow remains unchanged or is reduced.…”