{
  "abstract": "Background and Objectives Quantifiable parameters for assessing intracranial hypertension (IH) are limited. Normally, arterial and venous signals are in reverse phase, as arterial inflow displaces venous blood to maintain constant intracranial volume, in line with the Monro-Kellie doctrine. We developed a novel computational approach to analyze cerebral angiograms paired with simultaneous cardiac signals from pulse oximetry. Using wavelet transformation, each voxel is analyzed to derive amplitude and phase relative to the cardiac signal, creating cardiac-frequency-weighted angiograms. This feasibility study aimed to test arteriovenous (AV) coherence as a hemodynamic parameter derived solely from angiograms, enabling assessment of disturbed hemodynamics without direct pressure measurement.Methods Five patients with venous outflow stenosis underwent computational analysis of cerebral angiograms. For every voxel, amplitude and phase relative to the cardiac signal were calculated to quantify the impact of cardiac pulsatility on contrast washout, generating cardiac-frequency-weighted angiograms. Phase shift between arterial peaks and venous sinus signals was quantified to assess AV coherence. In addition, venous pressures were directly measured at multiple points for validation of stenosis hemodynamics and stenting effects.Results Before stenting, patients exhibited highly coherent, more in-phase arterial and venous signals, indicating impaired venous outflow and loss of normal reverse-phase physiology. After stenting, AV coherence decreased, producing more out-of-phase arterial and venous signals, consistent with restoration of physiological AV coupling. On average, phase shifts increased by approximately third of the cardiac cycle (~60°) after stenting compared to pre-stent measurements (p < 0.05). Venous pressure measurements confirmed pressure equalization across the stenosis (ΔP 16 mmHg pre-stent vs 4 mmHg post-stent, p < 0.05). Clinically, 6/8 patients demonstrated improvement in symptoms.Conclusions This feasibility study demonstrates that AV coherence derived from angiograms is a practical hemodynamic parameter capable of detecting disturbed cerebral venous outflow and restoration after intervention. By analyzing amplitude and phase of each voxel relative to the cardiac signal, reflecting the impact of cardiac pulsatility on contrast washout, combined with direct pressure validation, this approach provides a quantitative, noninvasive framework for mapping cerebral venous hemodynamics and assessing interventions in intracranial hypertension.Disclosures O. Doron: None. A. Patel: None. W. Butler: None.Abstract E-356 Figure 1",
  "authors": [
    {
      "affiliations": [
        "Neurosurgery, University of Chicago, Chicago, IL"
      ],
      "name": "O Doron"
    },
    {
      "affiliations": [
        "Neurosurgery, MGH, Boston, MA"
      ],
      "name": "A Patel"
    },
    {
      "affiliations": [
        "Neurosurgery, Massachusetts General Hospital, Boston, MA"
      ],
      "name": "R Regenhardt"
    },
    {
      "affiliations": [
        "Massachusetts General Hospital, Boston, MA"
      ],
      "name": "C Stapleton"
    },
    {
      "affiliations": [
        "Neurosurgery, MGH, Boston, MA"
      ],
      "name": "W Butler"
    }
  ],
  "title": "E-356 Quantifying cerebral hemodynamics with angiogram derived arteriovenous coherence - feasibility, physiological validation, and clinical application in venous stenting for venous outflow stenosis",
  "uid": "d8da8f8f-9d25-58da-9b39-b254aa212733"
}