Continuing medical educationThe role of imaging in the management of patients with nonmelanoma skin cancer: Diagnostic modalities and applications
Introduction
As the incidence of skin cancer continues to rise, dermatologists and dermatologic surgeons in particular will encounter more aggressive tumors that may require imaging to optimize patient work-up and management. However, radiologic imaging of skin cancer is not a familiar topic to most dermatologists. There are but a few sources of information found in radiology texts1 and the dermatologic literature,2, 3 and it remains a knowledge gap in dermatology. In addition to streamlining patient care, an understanding of different imaging modalities will facilitate the use of cost effective imaging resources.4, 5 The objective of this article is to provide a current overview of imaging modalities pertinent to nonmelanoma skin cancer (NMSC) and to discuss clinical scenarios where imaging is indicated. For reasons of brevity and relevance to this audience, the discussion will exclude melanoma.
Section snippets
Anatomic planes of imaging
Cross-sectional imaging requires standard nomenclature to refer to the visualized plane. A correct understanding of the terminology used by radiologists is essential in the interpretation of imaging reports and communication. The commonly used anatomic planes in imaging studies (ie, axial or transverse, sagittal, and coronal) are shown in Fig 1.
Computed tomography basics
Key points Computed tomography is typically the initial imaging study in the preoperative evaluation of head and neck tumors Computed tomography scans offer superior spatial resolution compared to magnetic resonance imaging scans and excellent visualization of bony structures and lymph nodes Computed tomography scans can be quickly performed and are widely available Computed tomography scans involve exposure to ionizing radiation Computed tomography scans should be ordered with contrast for tumor imaging
Positron emission tomography–computed tomography basics
Key points Positron emission tomography–computed tomography is an excellent technique for the detection of hypermetabolic tumors, such as squamous cell and Merkel cell carcinomas, in lymph nodes and distant organs Positron emission tomography–computed tomography provides both structural and functional data Positron emission tomography–computed tomography is frequently used to evaluate the presence of occult metastases and monitor head and neck tumors postoperatively
Positron emission tomography–computed
Magnetic resonance imaging: The basics
Key points Magnetic resonance imaging scans have superior soft tissue contrast compared to computed tomography scans Magnetic resonance imaging scans allow for the evaluation of perineural invasion These scans do not involve ionizing radiation Cost, longer imaging time, and sensitivity to motion and magnetic interference can be drawbacks Magnetic resonance imaging scans should be ordered with contrast for tumor imaging
MRI scans, in contrast to CT scans, use no ionizing radiation. The first requirement is a
Basics of ultrasonography
Key points Ultrasonography is a noninvasive modality Ultrasonography can assess regional lymph node characteristics Ultrasonography is operator-dependent The evaluation of cutaneous tumors with ultrasonography requires specialized equipment
Ultrasonography (US) has been an essential tool in medical diagnosis since its emergence approximately 60 years ago. It can be used to image the primary tumor or assess lymph nodes.39, 40, 41, 42, 43, 44 High-frequency sound waves generated by the piezoelectric crystals in
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Funding sources: None.
Conflicts of interest: None declared.
Date of release: April 2017
Expiration date: April 2020