Primary staging of laryngeal and hypopharyngeal cancer: CT, MR imaging and dual-energy CT.
Laryngeal and hypopharyngeal cancer, in particular T4a disease associated with cartilage invasion and extralaryngeal spread, needs to be evaluated accurately because treatment can impact heavily on a patient's quality of life. Reliable imaging tools are therefore indispensible. CT offers high spatial and temporal resolution and remains the preferred imaging modality. Although cartilage invasion can be diagnosed with acceptable accuracy by applying defined criteria for combinations of erosion, lysis and transmural extralaryngeal spread, iodine-enhanced tumors and non-ossified cartilage are sometimes difficult to distinguish. MR offers high contrast resolution for images without motion artifacts, although inflammatory changes in cartilage sometimes resemble cartilage invasion. With dual-energy CT, combined iodine overlay images and weighted average images can be used for evaluation of cartilage invasion, since iodine enhancement is evident in tumor tissue but not in cartilage. Extralaryngeal spread can be evaluated from CT, MR or dual-energy CT images and the routes of tumor spread into the extralaryngeal soft tissue must be considered; (1) via the thyrohyoid membrane along the superior laryngeal neurovascular bundle, (2) via the inferior pharyngeal constrictor muscle, and (3) via the cricothyroid membrane. Radiologists need to understand the advantages and limitations of each imaging modality for staging of laryngeal and hypopharyngeal cancer.
Diagnostic Radiology Division, National Cancer Center Hospital East, 6-5-1, Kashiwanoha, Kashiwa, Chiba 277-8577, Japan. Electronic address: hkuno@east.ncc.go.jp.
Hirofumi
H
Kuno
Diagnostic Radiology Division, National Cancer Center Hospital, 5-1-1 Tsukiji Chuo-ku, Tokyo 104-0045, Japan. Electronic address: honaya@ncc.go.jp.
Hiroaki
H
Onaya
Pathology Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577, Japan. Electronic address: sfujii@east.ncc.go.jp.
Satoshi
S
Fujii
Department of Radiology, Jikei University School of Medicine, 3-25-18 Nishi-shinbashi Minato-ku, Tokyo 105-8461, Japan. Electronic address: ojiri@jikei.ac.jp.
Hiroya
H
Ojiri
Imaging & Therapy Systems Division, Siemens Japan K.K., Gate City Osaki West Tower 1-11-1 Osaki, Shinagawa-ku, Tokyo 141-8644, Japan. Electronic address: katharina.otani@siemens.com.
Katharina
K
Otani
Diagnostic Radiology Division, National Cancer Center Hospital East, 6-5-1, Kashiwanoha, Kashiwa, Chiba 277-8577, Japan. Electronic address: msatake@east.ncc.go.jp.
Mitsuo
M
Satake
D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000473:pathology*; D007822:Laryngeal Neoplasms / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009367:Neoplasm Staging; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
Computed tomography; Dual-energy CT; Hypopharyngeal cancer; Laryngeal cancer; Magnetic resonance imaging; Staging