Imaging ofTemporal BoneTumors Bert De Foer, MD a, *, Christoph Kenis, MD a , Jean-PhilippeVercruysse, MD b ,Thomas Somers, MD, PhD b , Marc Pouillon, MD a , Erwin Offeciers, MD, PhD b , Jan W. Casselman, MD, PhD a,c,d This article presents an overview of tumoral lesions of the temporal bone. These lesions are rather rare. Imaging plays a crucial role in describing the exact extent of these lesions and can be helpful in specifying some of these lesions. Classification of these tumors can be made based on location and origin, age of the patient, histo- logic findings, and benign or malignant aspect of the lesion. Specific attention should be paid to the young age group, because several tumoral entities are specific for this age group. Special attention should also be paid to various types of pseudolesions and benign lesions mimicking tu- moral lesions. These lesions should definitely not be ‘‘touched’’ because any treatment might be harmful to the patient. In this article, classification of tumoral lesions is made based on location of the lesion: external ear, middle ear, or petrous bone/membranous laby- rinth. The most common tumoral lesions are dis- cussed. Several more rare entities are highlighted also. Petrous bone apex lesions are not discussed because they are the subject of a separate article in this issue. IMAGING Technical Aspects For the evaluation of a suspected tumor of the temporal bone, CT and MR imaging are used. CT is used to evaluate the osseous invasion by the tumor. The aspect of bone invasion can provide additional information regarding the type of tumor. MR imaging has superior contrast resolution. Various pulse sequences can be used. The use of intravenously administered gadolinium is highly recommended to visualize the enhancement of tumor, soft tissues, meninges, and surrounding vascular structures. High-Resolution CT Multidetector CT is used to acquire a volume data set from which multiple reconstructions can be made in different planes and in various reconstruc- tion thicknesses. Contrary to CT performed for conductive hearing loss, CT performed for suspi- cion of a tumoral lesion should always be con- ducted using intravenously administered iodinated contrast medium. The data set should be acquired in soft tissue and by means of a high-resolution bone algorithm to allow evalua- tion of the soft tissues and the bony details of the temporal bone. Usually, submillimetric acquisi- tion is performed. Multiplanar reconstructions can give additional information regarding the exact extension of the tumor and the invasion of vascular structures, nerve channels, and the membranous labyrinth. a Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk, Belgium b University Department of Ear, Nose, and Throat, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk, Belgium c Department of Radiology, AZ Sint-Jan AV Hospital, Ruddershove 10, 8000 Bruges, Belgium d Department of Radiology, University Hospital, De Pintelaan 185, 9000 Ghent, Belgium * Corresponding author. E-mail address: bert.defoer@GZA.be (B. De Foer). KEYWORDS  Temporal bone  Neoplasm  MR imaging  CT  Skull base Neuroimag Clin N Am 19 (2009) 339–366 doi:10.1016/j.nic.2009.06.003 1052-5149/09/$ – see front matter ª 2009 Elsevier Inc. All rights reserved. neuroimaging.theclinics.com