THE TEMPORAL BONE : Contemporary Diagnostic Dilemmas - 09/09/11

Doi : 10.1016/S0033-8389(05)70066-X

Joel D. Swartz, MD ^a, H. Ric Harnsberger, MD ^b, Suresh K. Mukherji, MD ^c

^a Department of Imaging Services, The Germantown Hospital and Medical Center (JDS), Philadelphia, Pennsylvania

^b Section of Neuroradiology, Department of Radiology, The University of Utah Medical Center (HRH), Salt Lake City, Utah

^c Department of Radiology, University of North Carolina Medical Center; and the University of North Carolina School of Dentistry (SJM), Chapel Hill, North Carolina

Résumé

The entire topic of temporal bone imaging cannot be addressed in a single Radiologic Clinics of North America article. In consultation with the editor, We have decided to limit our discussion to topics about which there have been particularly important advances in recent years: inflammatory disease, sensorineural hearing deficit, pulsative tinnitus (PT), facial nerve dysfunction, and the postoperative temporal bone. The common thread linking those sections is an attempt to emphasize the following potential pitfalls:

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Inflammatory Disease

•

Acute otomastoiditis

•	Failure to recognize coalescent disease (erosion of mastoid septae)
•	Failure to diagnose sigmoid sinus thrombosis

•

Chronic otomastoiditis

•	Failure to diagnose labyrinthine fistula
•	Overdiagnosis of cholesteatoma (absent bony erosion)
•	Failure to diagnose tegmen-sinus plate defects

•

Sensorineural Hearing Deficit

•

Failure to utilize precontrast T1-weighted images

•	Intralabyrinthine hemorrhage
•	Lipoma
•	Intratumoral hemorrhage

•

Failure to identify pneumolabyrinth (perilymphatic fistula)

•

Failure to diagnose vestibular aqueduct syndrome (most common cause of congenital sensorineural hearing defect for which there is an imaging correlate)

•

Overdiagnosis of Mondini's disease

•

Failure to identify intra-axial causes (especially lesions involving the cochlear nuclear complex) of hearing loss

•

Failure to identify intralabyrinthine disorders

•	Schwannoma
•	Labyrinthitis
•	Hemorrhage

•

Pulsatile Tinnitus

•	Failure to understand that asymmetry of the jugular foramina is a normal variation
•	Failure to understand that interruption of cortication of the foramen is abnormal regardless of foramen size
•	Failure to diagnose vascular variants (especially aberrant internal carotid artery)
•	Misdiagnosis of endolymphatic sac tumor for glomus jugulare

•

Facial Nerve Dysfunction

•	Failure to study entire course of facial nerve
•	Failure to diagnose protruding tympanic segment of nerve into oval window
•	Failure to recognize the normal enhancement pattern of the intratemporal facial nerve

•

Postoperative Temporal Bone

•	Failure to diagnose meningoencephalocele (lack of appreciation of tegmen defects)
•	Failure to appreciate abnormal communication between IAC fundus and inner ear (leading to perilymphatic gusher upon stapes manipulation)
•	Misdiagnosing incus interposition as traumatic dislocation
•	Failure to identify an uncovered portion of the facial nerve canal prior to reoperation

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Plan

ACUTE OTOMASTOIDITIS, CHRONIC OTOMASTOIDITIS, AND COMPLICATIONS

THE IAC AND CPA

EVALUATION OF PT

FACIAL NERVE

THE POSTOPERATIVE TEMPORAL BONE

Address reprint requests to Joel D. Swartz, MD, Department of Radiology, The Germantown Hospital and Medical Center, One Penn Boulevard, Philadelphia, PA 19144