[Role of computed tomographic angiography in the evaluations of dural arteriovenous fistulas with pulsatile tinnitus as initial symptom].

OBJECTIVE

To evaluate the sensitivity and specificity of computed tomographic angiography ( CTA) for dural arteriovenous fistulas ( DAVFs) in patients presenting with pulsatile tinnitus( PT).

METHODS

The clinical and imaging data were collected for all patients undergoing CTA for PT from 2008 to 2012. Nine PT patients with DAVFs confirmed by digital subtraction angiography ( DSA) and 9 age and gender-matched control PT patients without DAVFs were selected. The CTA images were blindly analyzed by two experienced neuroradiologists for the following signs: asymmetric venous collaterals in extracranial space , asymmetric attenuation of internal jugular vein ( IJV) , asymmetric external carotid artery( ECA) branches, "shaggy" appearance of dural venous sinus, multiple transcalvarial channels, enlarged foramen spinosum, asymmetric cavernous sinus and enlarged cortical veins.

RESULTS

The sensitivities of the following DAVFs signs were quite different: asymmetric attenuation of IJV ( 89% ) , asymmetric venous collaterals ( 89%) , asymmetric ECA branches ( 78%) , shaggy dural venous sinus ( 67%) , multiple transcalvarial channels (67%), enlarged foramen spinosum (56%), stenosis of venous sinus (33%) and asymmetric cavernous sinus ( 2 2 % ) . The presence of asymmetric attenuation of IJV , asymmetric ECA branches, shaggy dural venous sinus, multiple transcalvarial channels and asymmetric cavernous sinus all demonstrated a highly specificity of 100% while the presence of asymmetric venous collaterals and enlarged foramen spinosum had a specificity of 89% . The presence of stenosis of venous sinus revealed a specificity of 78%. Enlarged cortical veins were all absent.

CONCLUSION

CTA may be used as a screening examination for DA VFs in PT patients. The presence of asymmetric venous collaterals, asymmetric attenuation of UV,asymmetric ECA branches, shaggy dural venous sinus and multiple transcalvarial channels has a high sensitivity and specificity for diagnosis. Enlarged ECA branches usually serve as DA VFs feeders.Meanwhile, DA VF should be considered in PT patients when multiple transcalvarial channels and enlarged foramen spinosum are detected on high-resolution CT of temporal bone.