HSC Section 8_April 2017

Imaging in pulsatile tinnitus

papilloedema, and visual disturbance. 9 In a series of 145 cases of PT, IIH was the most frequent diagnosis accounting for 56 cases. 9 There is a high prevalence of venous sinus stenoses (withmore than 90% of cases having bilateral stenoses on MRV; Fig. 13 ). 31 Imaging studies are aimed at excluding other causes of intra- cranial hypertension ( Fig. 14 ) but some associated imaging features, such as an empty sella, flattening of the posterior globes, and distension of the periop- tic arachnoid spaces, have been described. 32 Diagno- sis is made by measuring the opening pressure at lumbar puncture. Venous variations and anomalies are frequently associated with subjective PT. Some, such as venous sinus dominance and a high-riding jugular bulb ( Fig. 15 a) (which extends above the inferior border of the round window, occurring in 25% of the population), are far more prevalent than ve- nous tinnitus. This implies that although they may predispose to PT in some cases, the association is frequently speculative. If identified, there should be a continued search for other treatable causes of PT. Other entities related to venous PT include an aberrant anteromedially placed or laterally placed sigmoid sinus ( Fig. 15 b), venous sinus steno- ses, and large emissary or subcranial veins. 7,11,31 Venous anomalies and variations

rhythmic contractions of the muscle around the skull base result in objective PT. Such non-vascular tinnitus may not be pulse-synchronous. Disease of the middle ear and mastoid, such as cholesterol granuloma ( Fig. 16 ), patulous eustachian tubes, and dehiscent semicircular canals, are also documented causes. 6,33

Conclusion

PT has diverse causes. The aim of radiology is to demonstrate treatable causes. Combined CTA/V has the advantage of demonstrating middle ear, skull base, and vascular diseases in a single exam- ination, and is the ideal first-line radiological studying in patients without an intra/retrotym- panic mass. Small arteriovenous fistulae may be occult on cross-sectional imaging and require catheter angiography for diagnosis. 1. McFerran DJ, Phillips JS. Tinnitus. J Laryngol Otol 2007; 121 :201 e 8. 2. Stouffer JL, Tyler RS. Characterization of tinnitus by tinni- tus patients. J Speech Hear Disord 1990; 55 :439 e 53. 3. Levy RA, Arts HA. Predicting neuroradiologic outcome in pa- tients referred for audiovestibular dysfunction. AJNR Am J Neuroradiol 1996; 17 :1717 e 24. 4. Waldvogel D, Mattle HP, Sturzenegger M, et al. Pulsatile tinnitus d a review of 84 patients. J Neurol 1998; 245 : 137 e 42. 5. Sonmez G, Basekim CC, Ozturk E, et al. Imaging of pulsatile tinnitus: a review of 74 patients. Clin Imaging 2007; 31 : 102 e 8. 6. Remley KB, Coit WE, Harnsberger HR, et al. Pulsatile tinni- tus and the vascular tympanic membrane: CT, MR, and an- giographic findings. Radiology 1990; 174 :383 e 9. 7. Krishnan A, Mattox DE, Fountain AJ, et al. CT arteriography and venography in pulsatile tinnitus: preliminary results. AJNR Am J Neuroradiol 2006; 27 :1635 e 8. 8. Dietz RR, Davis WL, Harnsberger HR, et al. MR imaging and MR angiography in the evaluation of pulsatile tinnitus. AJNR Am J Neuroradiol 1994; 15 :879 e 89. 9. Sismanis A. Pulsatile tinnitus. A 15-year experience. Am J Otol 1998; 19 :472 e 7. 10. Roll JD, Urban MA, Larson 3rd TC, et al. Bilateral aberrant internal carotid arteries with bilateral persistent stapedial arteries and bilateral duplicated internal carotid arteries. AJNR Am J Neuroradiol 2003; 24 :762 e 5. 11. Branstetter 4th BF, Weissman JL. The radiologic evaluation of tinnitus. Eur Radiol 2006; 16 :2792 e 802. 12. Weissman JL, Hirsch BE. Imaging of tinnitus: a review. Radi- ology 2000; 216 :342 e 9. 13. Hafeez F, Levine R, Dulli D. Pulsatile tinnitus in cerebrovas- cular arterial diseases. J Stroke Cerebrovasc Dis 1999; 8 : 217 e 23. 14. Daneshi A, Hadizadeh H, Mahmoudian S, et al. Pulsatile tin- nitus and carotid artery atherosclerosis. Int Tinnitus J 2004; 10 :161 e 4. References

Non-vascular pulsatile tinnitus

Non-vascular causes of PT include muscular tinni- tus (palatal and middle ear myoclonus) where

Figure 16 T1-weighted, coronal MR image demon- strates a hyperintense left mastoid cholesterol granuloma.

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