Persistent Hemodynamic Changes in Ruptured Brain Arteriovenous Malformations

Abstract

Background and Purpose-Hemodynamic properties of brain arteriovenous malformations (AVMs) with risk factors for a future hemorrhage are essentially unknown. We hypothesized that AVMs with anatomic properties, which are associated with an increased rupture risk, exhibit different hemodynamic characteristics than those without these properties. Methods-Seventy-two consecutive patients with AVMs diagnosed by conventional angiography underwent MRI examination, including time-resolved 3-dimensional MR angiography. Signal-intensity curves derived from the timeresolved 3-dimensional MR angiography datasets were used to calculate relative blood flow transit times through the AVM nidus based on the time-to-peak parameter. For identification of characteristics associated with altered transit times, a multiple normal regression model was fitted with stepwise selection of the following regressors: intracranial hemorrhage, deep nidus location, infratentorial location, deep drainage, associated aneurysm, nidus size, draining venous stenosis, and number of draining veins. Results-A previous intracranial hemorrhage is the only characteristic that was associated with a significant alteration of the relative transit time, leading to an increase of 2.4 seconds (95% CI, 1.2-3.6 seconds;, P<0.001) without adjustment and 2.1 seconds (95% CI, 0.6-3.6 seconds; P=0.007) with adjustment for all other regressors considered. The association was independent of the bleeding age. Conclusion-Hemodynamic

On apples, oranges, and ARUBA

“…However, such patients represent a large portion of those with unruptured AVMs in the community, thereby compromising the generalisability of the study's findings. Furthermore, as the different AVM treatment modalities have progressed considerably during the last two decades [5,8,11,21,23], the threshold for proposing a prophylactic treatment of AVMs considered to harbour a high risk of rupture has been lowered, despite the results of different studies regarding the rupture risk factors [4,6,8,9,20]. Consequently, the patients included in ARUBA had possibly low-risk AVMs with a more favourable natural history.…”

Aneurysms Associated with Brain Arteriovenous Malformations

“…Most interesting, changes in AVM hemodynamics were found to persist long after hemorrhage and did not decrease with time. 12 The reported incidence of IAs associated with AVMs varies considerably among different studies (2.7%-58%). 13 In a recent meta-analysis on the natural history of brain AVMs, the incidence , an AVM nidus in relation to a branch of the left middle cerebral artery is noted.…”

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.…”

“…Several noninvasive imaging methods for hemodynamic quantification exist, such as time-resolved contrast-enhanced magnetic resonance angiography (MRA), yet with temporal resolution limited to ≈1 seconds, 2,3 or unenhanced timeresolved phase-contrast MRA, yet with a long acquisition time and no hemodynamic visual analysis. 4,5 Recently, unenhanced time-resolved spin-labeled MRA (4D-SL-MRA) has been reported to allow anatomic AVM characterization reliably 3 and to overcome previous limitations by achieving high temporal resolutions of 50 to 100 ms, [6][7][8] thus reducing vessel superposition 9 and increasing the accuracy of further quantitative analysis.…”