{
  "abstract": "Background Spinal dural arteriovenous fistulas (SDAVFs) and spinal epidural arteriovenous fistulas (SEDAVFs) with intradural venous drainage may present with similar clinical and imaging features but often require distinct therapeutic strategies. Reliable preoperative markers to differentiate these entities remain limited.Objective We sought to determine which clinical and MRI/MRA findings can reliably differentiate SDAVFs from SEDAVFs prior to angiography.Methods We retrospectively analyzed consecutive patients with angiographically confirmed spinal arteriovenous fistulas evaluated at a tertiary referral center between 2008 and 2025. A neuroradiologist reviewed pre-angiographic MRIs and MRAs, while being blinded to the final angiographic diagnosis. We compared different clinical and radiographic features between SDAVFs and SEDAVFs in a univariate fashion. Positive and negative likelihood ratios (LR) were calculated for statistically significant features.Results We included 77 SDAVFs and 43 SEDAVFs with intradural venous drainage in this analysis. Severity of myelopathy and duration of symptoms were similar between the two groups. Patients with SEDAVFs were more likely to have undergone prior spine surgery (34.9% vs. 14.3%, p=0.01). No differences were noted between SDAVFs and SEDAVFs in flow void presence, location, and prominence, extent of T2 cord signal, or extent of gadolinium-enhancement. A prominent filum terminale vein was more common among SEDAVFs (51.2% vs. 14.3%, p<0.01, LR +=3.6). An extradural fistula component was more commonly visualized among SEDAVFs (32.6% vs. 9.1%, p<0.01, LR+=3.6). The neuroradiologist was able to identify the approximate location of the fistula before catheter angiography in 44 cases; among these, a localization at L1 or above was more common among SDAVFs (73.3% vs. 5.2%, p<0.01, LR+=10.3).Conclusions Clinical presentation and conventional MRI features do not reliably differentiate SDAVFs from SEDAVFs with retrograde intradural drainage. The presence of a filum terminale vein, an extradural fistula component, or fistula localization at L1 or higher on MRA can be moderately useful in this distinction in a fraction of cases.Disclosures C. Ranalli: None. G. Michalopoulos: None. C. Bilgin: None. G. Lanzino: None.",
  "authors": [
    {
      "affiliations": [
        "Neurological Surgery, Mayo Clinic, Rochester, MN"
      ],
      "name": "C Ranalli"
    },
    {
      "affiliations": [
        "Neurological Surgery, Mayo Clinic, Rochester, MN"
      ],
      "name": "G Michalopoulos"
    },
    {
      "affiliations": [
        "Radiology, Mayo Clinic, Rochester, MN"
      ],
      "name": "C Bilgin"
    },
    {
      "affiliations": [
        "Neurological Surgery, Mayo Clinic, Rochester, MN"
      ],
      "name": "G Lanzino"
    }
  ],
  "title": "E-273 Differentiating Between spinal dural and epidural arteriovenous fistulas before angiography: the role of clinical and radiographic findings",
  "uid": "10fe35c4-82c1-5c3b-bee7-0c807037ef47"
}