Dual energy CT in gland tumors: a comprehensive narrative review and differential diagnosis

Abstract

Dual energy CT (DECT)with image acquisition at two different photon X-ray levels allows the characterization of a specific tissue or material/elements, the extrapolation of virtual unenhanced and monoenergetic images, and the quantification of iodine uptake; such special capabilities make the DECT the perfect technique to support oncological imaging for tumor detection and characterization and treatment monitoring, while concurrently reducing the dose of radiation and iodine and improving the metal artifact reduction. Even though its potential in the field of oncology has not been fully explored yet, DECT is already widely used today thanks to the availability of different CT technologies, such as dual-source, single-source rapid-switching, single-source sequential, single-source twin-beam and dual-layer technologies. Moreover DECT technology represents the future of the imaging innovation and it is subject to ongoing development that increase according its clinical potentiality, in particular in the field of oncology. This review points out recent state-of-the-art in DECT applications in gland tumors, with special focus on its potential uses in the field of oncological imaging of endocrine and exocrine glands.

Keywords: Pancreas; dual energy CT; mammary gland; ovary; salivary glands.

Figure 1

Lipid-poor adenoma: incidental adrenal lesion observed on post-contrast CT images (A,B), was correctly demonstrated to be an adenoma with VNC images, derived from late phase, showing HU values lower than 10 (C).

Figure 2

In a 63-year-old patient with ovarian cancer and peritoneal carcinomatosis (A,B), DECT images (C,D) are helpful for detecting a peritoneal implant in rectouterine pouch, thanks to the increased conspicuity at low keV images. In metastatic patients, low keV images improve the visualization of peritoneal carcinomatosis especially in cases without free peritoneal fluid.

Figure 3

Seventy-eight-year-old patient with lobular carcinoma of left breast with a metastatic left axillary limphonodes (A,B,C,D,E). As you can see from the scatterplot (F), the concentration of iodine in breast lesions outlined with blue ROI and in the metastatic lymphonode marked with red ROI, are overlapping while a heathy lymphonode in the right axilla, marked with yellow ROI shows a different distribution of iodine.

Figure 4

Sixty-five-year-old patient with a left parotid gland tumour. At conventional CT image (A), the tumours’ margins are not clearly delineated; DECT image (B) allows a better visualisation of the tumour, inseparable from the left masseter muscle.