Head/Neck and Spine Imaging Variants: Introduction

Abstract

This book is separated into six different sections based on regional anatomy for the purpose of addressing the common modalities (such as CT or MRI), imaging sequences (particularly various MR sequences), and protocols (such as slice thickness or windowing) in order to identify each imaging variant in that region. These include: Sinonasal Variants (Chap. 2), Orbital Variants (Chap. 3), Head and Neck Variants (Chap. 4), Temporal Bone Variants (Chap. 5), Cervical and Thoracic Spine Variants (Chap. 6), and Lumbar Spine Variants (Chap. 7). Notably, the Head and Neck Variants chapter covers a wider range of anatomy and physiology (e.g., mucosal abnormalities, thyroid variants, salivary gland variants, Eagle syndrome, vascular variants and PET-CT variants) and thus is a bit more cursory because of the way neck CT imaging is routinely interpreted; perhaps this will be expounded on further in future editions, since some topics are quite vast in that region, and the anatomy is relatively compact. Furthermore, each of the above-mentioned six subjects tend to be subdivided further by sub-anatomic regions (e.g., “ossicular variants” within the Temporal Bone Variants chapter, “lacrimal gland” within the Orbital Variants chapter), and thus the variants of such regions are grouped together so that the differential diagnosis for true pathology and comparison to a known variant is practical; i.e. so a confident identification of the variant can be reached during routine image interpretation. Relevant references are provided for each subject. The goal of this text was to provide a quick, pictorial review with critical anatomy and imaging characteristics to facilitate prompt recognition of each variant; the reader is encouraged to review any of the numerous references included in each section for more in-depth learning.