Researchers have applied DECT to the detection of malignancy in the head and neck ( Table 1 for DECT parameter values). Tunlayadechanont and colleagues used DECT to differentiate inverted papilloma from squamous cell carcinoma (SCC) and lymphoma of the sinonasal cavity. The authors found significantly higher IC spectral attenuation curve (SAC) slope in SCC and lymphoma than in inverted papilloma.

DECT has been applied to the diagnosis of SCC metastatic to cervical lymph nodes (LNs), as nodal metastasis directly affect treatment options. Luo and colleagues found that oral SCC metastatic to LNs demonstrated significantly decreased ED, IC, normalized iodine concentration (nIC), slope of the energy spectrum curve ( λ _HU ), and dual-energy index compared with nonmetastatic nodes. Tu and colleagues evaluated laryngeal SCC metastatic to nodes and found that arterial phase nIC and normalized effective atomic number (nZ _eff ) independently predicted the presence of metastasis. Sun and colleagues examined esophageal cancer metastatic to nodes and found that IC and fat fraction were significantly lower in metastatic LNs.

DECT has also been applied to the diagnosis of LN metastases from other tumor types. Zhou and colleagues applied DECT to the diagnosis of metastatic papillary thyroid cancer (PTC) cervical LN metastasis. Specifically, the authors found that metastatic LNs had significantly higher extracellular volume fraction (ECV _D ) and arterial enhancement fraction (AEF _D ) than nonmetastatic LNs. ^, On a related matter, Geng and colleagues investigated whether Hashimoto’s thyroiditis (HT) had any confounding effect on DECT differentiation of metastatic and nonmetastatic PTC LNs. They found that HT resulted in lower values of IC, nIC, and Z _eff in diseased LNs and higher values of parameters in nondiseased LNs compared with LNs not affected by HT. Chen and colleagues evaluated lymphoma LNs and found that nIC, nZ _eff , normalized ED, and extracellular volume were all significantly elevated in patients with ¹⁸ FDG-PET hypermetabolic lymphoma.

An additional study evaluated whether DECT-derived 40 keV VMI provided improved soft tissue contrast compared with 70 keV VMI images (considered to be equivalent to conventional 120 keV single energy CT) in patients with oral, pharyngeal, and laryngeal SCC metastatic to LNs. The authors found significantly higher subjective and objective (Hounsfield units) contrast resolution for solid and necrotic components compared with adjacent sternocleidomastoid muscle.

Researchers have investigated the preoperative prediction of SCC aggressiveness. Zhang and colleagues evaluated whether DECT could predict recurrence-free survival in early-stage glottic cancer after larynx-preserving surgery. Although nIC values not otherwise specified were not statistically different between recurrence and nonrecurrence groups, the authors found that nIC limited to arterial and venous phases were significant predictors. Yang and colleagues evaluated whether preoperative DECT parameters were predictive of oral tongue SCC aggressiveness and found that venous phase λ _HU and nIC were significantly lower in stage III–IV lesions than in stage I–II lesions.

Researchers have applied pCT to patients with advanced head and neck cancers who undergo resections with free flap reconstruction. Current techniques to monitor free flap perfusion such as Doppler ultrasound and skin paddle monitors assess superficial but not deep tissue vasculature as pCT could. Ota and colleagues found significantly higher blood flow (17.3 mL/100 mL/min cutoff, AUC 0.96) and blood volume (5.62 mL/100 cutoff, 0.96 AUC) and significantly lower mean transit time (16.1 s cutoff, AUC 0.96) in flaps that remained viable at discharge compared with flaps that later failed (the authors also found significantly higher K _trans , V _p , and peak enhancement and shorter time to maximum enhancement with DCE perfusion MR imaging).