Ashok Srinivasan MD, Presenter: Author, Amirsys, Inc

Hideomi Yamauchi MD, Abstract Co-Author: Nothing to Disclose

Mark Alan Buehler MD, Abstract Co-Author: Nothing to Disclose

Matthew Spector, Abstract Co-Author: Nothing to Disclose

Suresh K. Mukherji MD, Abstract Co-Author: Nothing to Disclose

Mitchell M. Goodsitt PhD, Abstract Co-Author: Research collaboration, General Electric Company

1. To establish the normal range of dual energy CT derived parameters for normal tissues in the head and neck. 2. To evaluate the differences in dual energy CT parameters amongst normal tissues, benign and malignant neoplasms.  

Institutional review board approval was obtained. All adult CT neck scans performed on a 64 slice GE CT (HD750, Milwaukee, WI) with dual energy CT (Gemstone spectral imaging, GSI) from November 2009 to February 2014 were included. Scans with significant artifact or poor contrast bolus were excluded. Post processing was performed by an experienced neuroradiologist on a GE-AW workstation by placing multiple ROIs in normal tissues including the parotids, submandibular glands, floor of mouth, tongue base, lymph nodes, paraspinal muscle and in known tumor tissue (either benign or malignant). The parameters measured included HU at 70keV, effective Z and iodine-water concentrations. Mean, S.D. and range were calculated for each of these parameters within normal tissues and were then compared to the parameters measured in benign and malignant tumors using independent samples t-test. Scatterplots of effective Z against each of the other parameters were also created to analyze if benign and malignant tissues could be reliably separated using these parameters.

Patients with 17 benign and 24 malignant tumors were included. The mean and SD of effective Z and iodine-water concentration (in mg/cc) in normal tissues, benign and malignant tumors are listed in Table 1. Significant differences in effective Z and iodine-water concentrations was noted between benign and malignant neoplasms (p=0.001, 0.001 respectively) and between malignant neoplasms and all normal tissues but not between benign tumors and normal tissues. The scatterplotsof effective Z versus HU at 70 keV showed good separation of benign and malignant tumors.

Our study reveals that dual energy CT may help in distinguishing both benign and malignant tumors from each other, and differentiating malignant tumors from normal tissue in the head and neck. 

Dual energy CT can be an additional tool to conventional imaging in characterizing head and neck lesions. 

Srinivasan, A, Yamauchi, H, Buehler, M, Spector, M, Mukherji, S, Goodsitt, M, Establishing Normative Values of Dual-energy CT Parameters in Head and Neck Tissues and Comparison to Benign and Malignant Tumors .  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009320.html