In-room assessment of intravascular velocity from time-resolved rotational angiography in patients with arteriovenous malformation: a pilot study

BackgroundTime-resolved rotational angiography (t-RA) enables interventionists to better comprehend complex arteriovenous malformations (AVMs), thereby facilitating endovascular treatment. However, its use in evaluating hemodynamic changes has rarely been explored.ObjectiveThis study uses t-RA to estimate intravascular flow in patients with AVM to compare this with flow in the normal population.MethodsPatients with available t-RA scans were prospectively categorized into one of three groups: hemorrhagic AVM, non-hemorrhagic AVM and control. Pulsatile time-density curves (TDCs) for C1, C6 and VOIMCA were used for amplitude and velocity estimation. C1 was at the cervical internal carotid artery (ICA), 2-3cm below the carotid canal, C6 was at the paraclinoid segment of the ICA, and VOIMCA was at the junction of the first and second segment of the middle cerebral artery (MCA). A waveform amplitude ratio was defined as (peak - trough)/trough contrast intensity. V-ICA was defined as the distance between C6 and C1 divided by the time required for the wave to pass, and correspondingly, the average velocity of MCA (V-MCA) was defined as the distance between C6 and VOIMCA divided by the duration for the same peak to travel from C6 and VOIMCA, AVM volume was estimated by MR angiography.ResultsAmplitude ratios A(C1) and A(C6), and average flow velocities V-ICA and V-MCA were significantly larger in the non-hemorrhagic group than in the control group, while the hemorrhagic AVM group was not significantly different from the controls. V-ICA and V-MCA showed moderate to good correlations with AVM volume (r=0.51and 0.73, respectively). V-MCA (33.09.1) was significantly lower than V-ICA (41.3 +/- 13.2) in the control group, but not in the two AVM groups.ConclusionTDC waveform propagation derived from t-RA can quantify hemodynamic differences between AVM and the control group. t-RA provides both real-time anatomic and hemodynamic evaluation, and can thus potentially improve the interventional workflow.