Tuesday, 3 January 2012

Vascular loop and pulsatile tinnitus

Axial 3 D FIESTA study show a Vascular loop in Internal Auditory Canal around 7-8th CN complex on right side.
Is there any correlation between pulsatile tinnitus and a vascular loop in internal auditory canal ?

Tinnitus is a common disorder of sound in ear occurring without external stimulus and the etiology remains mostly unclear. Tinnitus may be classified as either Pulsatile (synchronous with an arterial pulse) or Non Pulsatile (Continuous). Nonpulsatile tinnitus is more common than pulsatile. Pulsatile tinnitus is most frequently the result of a vascular abnormality or a vascular tumor. However, in some cases, the etiology of tinnitus remains uncertain and most of these patients have no abnormalities on routine imaging like CT or routine MRI protocol used for brain evaluation.

With advent of 3D-FIESTA MR imaging which elegantly demonstrates the anatomy at IAC, more and more cases are mentioned with presence of a vascular loops in IAC around 7-8 CN complexes.

AJNR ; The prospective study approved by the institutional review board, all MR imaging examinations performed on 1.5T GE Signa Excite with addition of 3D-FIESTA sequence to the routine cranial MR imaging protocol.  Statistical Analysis done on MR imaging findings of the 3 groups (tinnitus group, control group, and the group consisting of asymptomatic sides of patients with unilateral tinnitus). Findings analyzed were presence of a vascular loop, vascular contact and the angulation of the eighth CN.

According to the study, the incidence of vascular loops around 8th CN is nearly the same in symptomatic as well as asymptomatic groups. 
Therefore, the presence of vascular loops within the IAC may not be a definite indication of vascular compression syndromes. Represents a normal anatomic variation, needs mention in the report but significance to be given in proper clinical context only and should not be used as a the diagnostic option in the decision of decompressive surgery.


Related posts:
Vascular-loop-syndrome - 5th CN compression
Vascular-loop-syndrome - 8th CN compression

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