Imaging findings in otitis media and resulting secondary lesions in dogs and cats – an image essay

Abstract

Over the past 2 decades, the increasing availability of computed tomography (CT) and magnetic resonance imaging (MRI) as well as the growing professional expertise have significantly improved the diagnostics of middle and inner ear diseases in dogs and cats. In answering some of the diagnostic questions, CT and MRT demonstrate equivalent performance. For most questions, however, there are differences in the diagnostic performance due to the physical imaging properties of the 2 modalities.

CT is more sensitive in demonstrating involvement of the bulla wall and is more effective for detecting abnormal content within the tympanic bulla. In addition, with CT it is often easier to guide tissue samplings. On the other hand, structural changes of the soft tissues of the skull, head, meninges, brain, and nerves are not or only insufficiently detectable on CT images. MRI is clearly superior here. Therefore, MRI is essential for the characterization of materials inside the bulla cavity and for demonstrating the extent of any central spread of otitis media (OM).

In this image essay, CT and MRI features of OM and resulting secondary lesions described in the literature are analyzed and summarized. Own image examples are used for illustration. Information on the etiology, pathogenesis, pathomorphology, and clinical signs important for understanding these changes are presented in concise descriptions.

Zusammenfassung

Über die letzten 2 Jahrzehnte haben die zunehmende Verfügbarkeit von Computertomografen (CT) und Magnetresonanztomografen (MRT) sowie die gewachsene fachliche Expertise die Diagnostik von Mittel- und Innenohrerkrankungen bei Hunden und Katzen erheblich verbessert. Bei der Beantwortung von einer Reihe diagnostischer Fragestellungen können CT und MRT als gleichwertige Verfahren angesehen werden. Bei anderen Fragestellungen wiederum bestehen Unterschiede in der diagnostischen Leistungsfähigkeit aufgrund der physikalischen Abbildungseigenschaften. Sensitiver ist die CT bei der Darstellung von Veränderungen der Bullawand. Die CT ist auch das effektivere Verfahren, wenn abnormaler Inhalt in der Bulla tympanica nachgewiesen werden soll. Darüber hinaus ist es mit der CT oft einfacher, die Entnahme von Gewebeproben zu planen und durchzuführen. Andererseits sind strukturelle Veränderungen der Weichteile des Kopfes, der Meningen, des Gehirns und von Nerven in der CT nicht oder nur unzureichend erkennbar. Hier ist die MRT klar überlegen. Daher ist die MRT für die Typisierung von Materialen in der Bulla sowie die Darstellung des Ausmaßes einer eventuell existierenden zentralen Ausbreitung einer Otitis media (OM) unerlässlich.

In diesem Bildessay werden die in der Literatur beschriebenen bildmorphologischen Merkmale einer OM und die durch sie bedingten sekundären Pathologien analysiert und zusammengefasst. Eigene Bildbeispiele dienen der Illustration. Für das Verständnis der Veränderungen wichtige Informationen zur Ätiologie, Pathogenese, Pathomorphologie und dem klinischen Erscheinungsbild werden in kurzer Form dargestellt.

Keywords

Computed tomography - magnetic resonance imaging - dog - cat - otitis media

Schlüsselwörter

Computertomografie - Magnetresonanztomografie - Hund - Katze - Otitis media

Publication History

Received: 04 June 2023

Accepted: 20 December 2023

Article published online:
26 June 2024

• References

• 1 Moore SA, Bentley RT, Carrera-Justiz S. et al. Clinical features and short-term outcome of presumptive intracranial complications associated with otitis media/interna: a multi-center retrospective study of 19 cats (2009-2017). J Feline Med Surg 2019; 21: 148-155 DOI: 10.1177/1098612X18764582.
• 2 Gotthelf LN. Diagnosis and treatment of otitis media in dogs and cats. Vet Clin Small Anim Pract 2004; 34: 469-487 DOI: 10.1016/j.cvsm.2003.10.007.
• 3 Detweiler DA, Johnson LR, Kass PH. et al Computed tomographic evidence of bulla effusion in cats with sinonasal disease: 2001-2004. J Vet Int Med 2006; 20: 1080-1084 DOI: 10.1892/0891-6640(2006)20. [1080:cteobe]2.0.co;2
• 4 Matsuda H, Tojo M, Fukui K. et al. The aerobic bacterial flora of the middle and external ears in normal dogs. J Small Anim Pract 1984; 25: 269-274 DOI: 10.1111/j.1748-5827.1984.tb03390.x.
• 5 Klose TC, MacPhail CM, Schultheiss PC. et al. Prevalence of select infectious agents in inflammatory aural and nasopharyngeal polyps from client-owned cats. J Feline Med Surg 2010; 12: 769-774 DOI: 10.1016/j.jfms.2010.05.013.
• 6 Shell LG. Otitis media and otitis interna. Etiology, diagnosis, and medical management. Vet Clin North Am Small Anim Pract 1988; 18: 885-899 DOI: 10.1016/s0195-5616(88)50088-8.
• 7 Swales N, Foster A, Barnard N. Retrospective study of the presentation, diagnosis and management of 16 cats with otitis media not due to nasopharyngeal polyp. J Feline Med Surg 2018; 20: 1082-1086 DOI: 10.1177/1098612X17746282.
• 8 Little CJL, Laue JG, Pearson GR. lnflammatory middle ear disease of the dog: the pathology of otitis media. Vet Rec 1991; 128: 293-296 DOI: 10.1136/vr.128.13.293.
• 9 Lorek A, Dennis R, van Dijk J. et al. Occult otitis media in dogs with chronic otitis externa – magnetic resonance imaging and association with otoscopic and cytological findings. Vet Dermatol 2020; 31: 146-153 DOI: 10.1111/vde.12817.
• 10 Shanaman M, Seiler G, Holt DE. Prevalence of clinical and subclinical middle ear disease in cats undergoing computed tomographic scans of the head. Vet Radiol Ultrasound 2011; 53: 76-79 DOI: 10.1111/j.1740-8261.2011.01873.x.
• 11 Bhutta MF, Thornton RB, Kirkham LAS. et al. Understanding the aetiology and resolution of chronic otitis media from animal and human studies. Dis Model Mech 2017; 10: 1289-1300 DOI: 10.1242/dmm.029983.
• 12 Salgüero R, Herrtage M, Holmes M. et al. Comparison between computed tomographic characteristics of the middle ear in non-brachycephalic and brachycephalic dogs with obstructive airway syndrome. Vet Radiol Ultrasound 2016; 57: 137-143 DOI: 10.1111/vru.12337.
• 13 Schünemann R, Kamradt A, Truar K. et al. Prevalence and characterization of middle ear effusion in 55 brachycephalic dogs. Tierärztl Prax - K 2022; 50: 329-336 DOI: 10.1055/a-1913-7216.
• 14 Töpfer T, Köhler C, Rösch S. et al. Brachycephaly in French bulldogs and pugs is associated with narrow ear canals. Vet Dermatol 2022; 33: 214-e60 DOI: 10.1111/vde.13067.
• 15 Mielke B, Lam R, Ter Haar G. Computed tomographic morphometry of tympanic bulla shape and position in brachycephalic and mesaticephalic dog breeds. Vet Radiol Ultrasound 2017; 58: 552-558 DOI: 10.1111/vru.12529.
• 16 Hayes GM, Friend EJ, Jeffery ND. Relationship between pharyngeal conformation and otitis media with effusion in Cavalier King Charles spaniels. Vet Rec 2010; 167: 55-58 DOI: 10.1136/vr.b4886.
• 17 Milne E, Nuttall T, Marioni-Henry K. et al. Cytological and microbiological characteristics of middle ear effusions in brachycephalic dogs. J Vet Intern Med 2020; 34: 1454-1463 DOI: 10.1111/jvim.15792.
• 18 Stern-Bertholtz W, Sjostrom L, Wallin Hakanson N. Primary secretory otitis media in the Cavalier King Charles spaniel: a review of 61 cases. J Small Anim Pract 2003; 44: 253-256 DOI: 10.1111/j.1748-5827.2003.tb00151.x.
• 19 Cole LK, Samii VF, Wagner SO. et al. Diagnosis of primary secretory otitis media in the Cavalier King Charles spaniel. Vet Dermatol 2015; 26: 459-466 DOI: 10.1111/vde.12248.
• 20 Drees R. External, Middle and Inner Ear. In: Schwarz T, Saunders J (eds). Veterinary Computed Tomography. Wiley-Blackwell; 2013: 153-160
• 21 Foster A, Morandi F, May E. Prevalence of ear disease in dogs undergoing multidetector thin-slice computed tomography of the head. Vet Radiol Ultrasound 2015; 56: 18-24 DOI: 10.1111/vru.12180.
• 22 Belmudes A, Pressanti C, Barthez PY. et al. Computed tomographic findings in 205 dogs with clinical signs compatible with middle ear disease: a retrospective study. Vet Dermatol 2018; 29: 45-e20 DOI: 10.1111/vde.12503.
• 23 Garosi LS, Lamb CR, Targett MP. MRI findings in a dog with otitis media and suspected otitis interna. Vet Rec 2000; 146: 501-502 DOI: 10.1136/vr.146.17.50.
• 24 Owen MC, Lamb CR, Lu D. et al. Material in the middle ear of dogs having magnetic resonance imaging for investigation of neurologic signs. Vet Radiol Ultrasound 2004; 45: 149-155 DOI: 10.1111/j.1740-8261.2004.04025.x.
• 25 Sturges BK, Dickinson PJ, Kortz GD. et al Clinical signs, magnetic resonance imaging features, and outcome after surgical and medical treatment of otogenic intracranial infection in 11 cats and 4 dogs. J Vet Intern Med 2006; 20: 648-656 DOI: 10.1892/0891-6640(2006)20. [648:csmrif]2.0.co;2
• 26 Saunders JH, Boroffka AEB. External, Middle, and Inner Ear. In: Mai W (ed). Diagnostic MRI in Dogs and Cats. Boca Raton-London-New York: . CRC-Press; 2018: 380-392
• 27 Negrin A, Cherubini GB, Lamb C. et al. Clinical signs, magnetic resonance imaging findings and outcome in 77 cats with vestibular disease: a retrospective study. J Feline Med Surg 2010; 12: 291-299 DOI: 10.1016/j.jfms.2009.10.001.
• 28 Orlandi R, Gutierrez-Quintana R, Carletti B. et al. Clinical signs, MRI findings and outcome in dogs with peripheral vestibular disease: a retrospective study. BMC Vet Res 2020; DOI: 10.1186/s12917-020-02366-8.
• 29 Castillo G, Parmentier T, Monteith G. et al. Inner ear fluid-attenuated inversion recovery MRI signal intensity in dogs with vestibular disease. Vet Radiol Ultrasound 2020; 61: 531-539 DOI: 10.1111/vru.12876.
• 30 Foth S, Meller S, De Decker S. et al. Unilateral decrease in inner ear signal in fluid-attenuated inversion recovery sequences in previously suspected canine idiopathic vestibular syndrome. Vet J 2021; 277: 105748 DOI: 10.1016/j.tvjl.2021.105748.
• 31 Everest S, Monteith G, Gaitero L. et al Suppression of inner ear signal intensity on fluid-attenuated inversion recovery magnetic resonance imaging in cats with vestibular disease. J Feline Med Surg 2023; 25 1098612X231168001 doi: 1098612X231168001
• 32 Mellema LM, Samii VF, Vernau KM. et al. Meningeal enhancement on magnetic resonance imaging in 15 dogs and 3 cats. Vet Radiol Ultrasound 2002; 43: 10-15 DOI: 10.1111/j.1740-8261.2002.tb00435.x.
• 33 Ferlito A, Devaney KO, Rinaldo A. et al. Clinicopathological consultation: ear cholesteatoma versus cholesterol granuloma. Ann Otol Rhinol Laryngol 1997; 106: 79-85 DOI: 10.1177/000348949710600114.
• 34 Semaan MT, Megerian CA. The pathophysiology of cholesteatoma. Otolaryngol Clin N Am 2006; 39: 1143-1159 DOI: 10.1016/j.otc.2006.08.003.
• 35 Olszewska E, Wagner M, Bernal-Sprekelsen M. et al. Etiopathogenesis of cholesteatoma. Eur Arch Otorhinolaryngol 2004; 261: 6-24 DOI: 10.1007/s00405-003-0623-x.
• 36 Castle J. Cholesteatoma pearls: practical points and update. Head Neck Pathol 2018; 12: 419-429 DOI: 10.1007/s12105-018-0915-5.
• 37 Risselada M. Diagnosis and management of cholesteatomas in dogs. Vet Clin North Am Small Anim Pract 2016; 46: 623-634 DOI: 10.1016/j.cvsm.2016.01.002.
• 38 Hardie EM, Linder KE, Pease AP. Aural cholesteatoma in twenty dogs. Vet Surg 2008; 37: 763-770 DOI: 10.1111/j.1532-950X.2008.00455.x.
• 39 Travetti O, Guidice C, Greci V. et al. Computed tomography features of middle ear cholesteatoma in dogs. Vet Radiol Ultrasound 2010; 51: 374-379 DOI: 10.1111/j.1740-8261.2010.01682.x.
• 40 Greci V, Travetti O, Di Giancamillo M. et al. Middle ear cholesteatoma in 11 dogs. Can Vet J 2011; 52: 631-636
• 41 Isaacson B, Kutz JW, Roland PS. Lesions of the petrous apex: diagnosis and management. Otolaryngol Clin North Am 2007; 40: 479-519 DOI: 10.1016/j.otc.2007.03.003.
• 42 Connor SE, Leung R, Natas S. Imaging of the petrous apex: a pictorial review. Br J Radiol 2008; 81: 427-435 DOI: 10.1259/bjr/54160649.
• 43 Eisenberg MB, Haddad G, Al-Mefty O. Petrous apex cholesterol granulomas: evolution and management. J Neurosurg 1997; 86: 822-829 DOI: 10.3171/jns.1997.86.5.0822.
• 44 Hoeffner E, Mukherji S, Gandhi G. et al. Temporal Bone Imaging Book. Thieme; 2022. ISBN:1588904016
• 45 Fliegner RA, Jubb KVF, Lording PM. Cholesterol granuloma associated with otitis media and destruction of the tympanic bulla in a dog. Vet Pathol 2007; 44: 547-549 DOI: 10.1354/vp.44-4-547.
• 46 Riedinger B, Albaric O, Gauthier O. Cholesterol granuloma as long-term complication of total ear canal ablation in a dog. J Small Anim Pract 2012; 53: 188-191 DOI: 10.1111/j.1748-5827.2011.01157.x.
• 47 Chapman PR, Shah R, Curé JK. et al. Petrous apex lesions: pictorial review. Am J Roentgenol 2011; 196: WS26-WS37 DOI: 10.2214/AJR.10.7229.
• 48 Razek A, Huang B. Lesions of the petrous apex: classification and findings at CT and MR imaging. Radiographics 2012; 32: 151-173 DOI: 10.1148/rg.321105758.
• 49 Doulidis PG, Klang A, Gumpenberger M. et al. Bilateral cholesterol granulomas in the middle ear cavities of a cat with sinonasal disease successfully removed via video-otoscopy. J Am Vet Med Assoc 2022; 260: 1-4 DOI: 10.2460/javma.21.03.0149.
• 50 Hoa M, House JW, Linthicum FH. et al. Petrous apex cholesterol granuloma: pictorial review of radiological considerations in diagnosis and surgical histopathology. J Laryngol Otol 2013; 127: 339-348 DOI: 10.1017/S0022215113000091.
• 51 Luo L, Gong S, Bai G. et al. A retrospective study on cholesteatoma otitis media coexisting with cholesterol granuloma. J Huazhong Univ Sci Technolog Med Sci 2002; 22: 168-170 DOI: 10.1007/BF02857685.