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Brief Report
December 2018

Unique Gadolinium Enhancement Pattern in Spinal Dural Arteriovenous Fistulas

Author Affiliations
  • 1Department of Neurology, Mayo Clinic, Rochester, Minnesota
  • 2Department of Radiology, Mayo Clinic, Rochester, Minnesota
JAMA Neurol. 2018;75(12):1542-1545. doi:10.1001/jamaneurol.2018.2605
Key Points

Question  Does a gadolinium-enhanced magnetic resonance imaging pattern help in distinguishing a spinal dural arteriovenous fistula from other causes of myelopathy?

Findings  This medical record review included 51 patients with a spinal dural arteriovenous fistula and pretreatment magnetic resonance imaging with gadolinium. Of these, 44 (86%) had intraparenchymal contrast enhancement, and 19 of these patients (43%) displayed the missing-piece sign defined by at least 1 focal geographic nonenhancing area within a long segment of intense holocord gadolinium enhancement.

Meaning  Identifying this unique radiographic finding could potentially result in earlier time to angiography with improved outcomes for patients with spinal dural arteriovenous fistulas.

Abstract

Importance  Spinal dural arteriovenous fistula (sDAVF) is often misdiagnosed as an inflammatory or a neoplastic myelopathy, often because of intraparenchymal gadolinium enhancement on magnetic resonance imaging (MRI); proper early diagnosis is important because deficits are reversible and a delay in treatment is associated with permanent morbidity. Tortuous flow voids on MRI are not universally present; thus, recognition of a unique gadolinium enhancement pattern may also aid in the early recognition and treatment of sDAVF.

Objective  To describe a unique pattern of spinal cord gadolinium enhancement on MRI in sDAVF.

Design, Setting, and Participants  This retrospective evaluation included pretreatment MRIs from 80 patients referred to the Mayo Clinic, Rochester, Minnesota, from January 1, 1997, through December 31, 2017, with a confirmed diagnosis of sDAVF and a control group of 144 patients with alternative confirmed myelopathy diagnoses. All participants underwent a neurologic evaluation at the Mayo Clinic.

Main Outcomes and Measures  Evidence of at least 1 focal geographic nonenhancing area within a long segment of intense holocord gadolinium enhancement (termed the missing-piece sign) on MRI.

Results  Of 51 patients with an sDAVF and a pretreatment MRI with gadolinium enhancement, 44 (86%) had intraparenchymal contrast enhancement, and 19 of these patients (43%) displayed the characteristic missing-piece sign. Of these 19 patients, symptom onset occurred at a median age of 67 years (range, 27-80 years); 15 patients were men. Progressive myelopathy features affecting the lower extremities occurred during a median of 33 months (range, 1-84 months). Eleven patients (58%) received an alternative diagnosis before confirmation of sDAVF. Tortuous flow voids were present on T2-weighted MRI in 13 of 19 patients. More than 1 digital subtraction angiogram was required for 5 patients to confirm the diagnosis. The missing-piece sign was not seen in any patients from the control group.

Conclusions and Relevance  This unique gadolinium enhancement pattern in sDAVF was not found in a large control group of patients with other myelopathy. Identifying the missing-piece sign on MRI could potentially result in earlier time to angiography with improved outcomes for patients with an sDAVF.

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