1. Parallel Dural Sinus Dural AV Fistula: Diagnosis and Treatment Hon-Man Liu, MD,MBA National Taiwan University Hospital Taipei, Taiwan Conflict of interest: none

2. 42M, pulsated tinnitus

3. 34 F, vascular tinnitus, insomnia, headache

5. Parallel sinus DAVF Other sinus DAVF Fistula site Sinus wall Supplying arteries

6. Parallel dural sinus DAVF Fistulae site is inside the dural wall. They form venous channels inside the wall, which may run parallel to the sinus. It can drain to the sinus or adjacent cortical veins. The adjacent sinus may be patent or partial occluded. It can occur in different location. It can be associated with other type of DAVF such as osseous type or dural sinus type.

7. DAVF, total N=120 Parallel sinus DAVF N=12 Male =8Female=8 Other types of DAVF N=108 Average age: 53.2y (SD=12.8y) National Taiwan University Hospital 2008.04-2010.04

8. Parallel sinus DAVF N=12 Transverse-sigmoid N=8 Progressive dementia N=1 Pulsated tinnitus N=7 Superior saggital sinus N=4 Neurological deficit N=4 Associated with sinus thrombosis N=3

9. Treatment of parallel dural sinus DAVF Identify the exact location of the fistulae site The sinus or important normal drainage approximate to the lesion should be preserved Sometimes combination with other methods Stuffing or packing between the 2 layers of dura mater with coils

10. Hybrid CTA Radiology 2010 Jul;256(1):219-28. Subtraction CTA Pre-contrast CTPost-contrast CT Original CTA MMBE CTA DAVF occurs at dural sinus to which is proximate or inside the skull bones. Therefore, it is difficult to demonstrate the detail vascular pattern and to make diagnosis of DAVF on conventional CTA, even more for parallel sinus DAVF

11. 56 F, pulsated tinnitus, recent onset seizure

13. 42M, pulsated tinnitus

14. Fistula site Via occluded sigmoid sinus Save the vein of Labbe 34 F, vascular tinnitus, insomnia, headache

16. Treatment TVE coiling (n=7) TVE coiling & NBCA (n=3) Angioplasty for sinus stenosis or obstruction (n=2) TAE &TVE coiling (n=2) Outcome good in 9 Outcome Stable in 3

17. Conclusion Parallel sinus DAVF is not rare Precise diagnosis is important Mis-diagnosis might cause disaster such as occluding the normal sinus