Imaging the External Ear: Practical Approach to Normal and Pathologic Conditions

Area of Science:

• Radiology
• Otolaryngology
• Anatomy

Background:

• The external ear (EE), comprising the auricle and external auditory canal (EAC), is accessible but requires imaging for deep lesions or treatment resistance.
• Congenital, traumatic, inflammatory, neoplastic, and vascular conditions can affect the EE, necessitating accurate diagnostic approaches.

Purpose of the Study:

• To provide an overview of the anatomy and embryologic development of the external ear.
• To discuss and illustrate common and uncommon conditions affecting the EE structures.
• To highlight CT and MRI features crucial for radiologists in diagnosing EE abnormalities.

Main Methods:

• Review of external ear anatomy, embryology, and associated pathologies.
• Analysis of CT and MRI features for evaluating external ear lesions.
• Development of a flowchart for differential diagnosis of external ear abnormalities.

Main Results:

• CT is the primary modality for EAC evaluation and bone changes.
• MRI offers superior tissue characterization and defines lesion extension, including perineural spread.
• Illustrations and descriptions of various EE conditions and their imaging characteristics are presented.

Conclusions:

• A foundational understanding of EE anatomy and embryology is vital for accurate diagnosis.
• CT and MRI play complementary roles in evaluating external ear pathologies.
• The provided flowchart assists radiologists in the differential diagnosis of external ear abnormalities.