From the Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, GRB-273A, Boston, MA 02114.http://pubs.rsna.org/doi/abs/10.1148/radiol.2015150877
Ranliang Hu, MD , Laleh Daftari Besheli, MD , Joseph Young, MD , Markus Wu, MD , Stuart Pomerantz, MD , Michael H. Lev, MD , Rajiv Gupta, MD, PhD
Purpose
To evaluate the ability of dual-energy (DE) computed tomography (CT) to differentiate calcification from acute hemorrhage in the emergency department setting.
Materials and Methods In this institutional review board-approved study, all unenhanced DE head CT examinations that were performed in the emergency department in November and December 2014 were retrospectively reviewed. Simulated 120-kVp single-energy CT images were derived from the DE CT acquisition via postprocessing. Patients with at least one focus of intraparenchymal hyperattenuation on single-energy CT images were included, and DE material decomposition postprocessing was performed. Each focal hyperattenuation was analyzed on the basis of the virtual noncalcium and calcium overlay images and classified as calcification or hemorrhage. Sensitivity, specificity, and accuracy were calculated for single-energy and DE CT by using a common reference standard established by relevant prior and follow-up imaging and clinical information.
Results
Sixty-two cases with 68 distinct intraparenchymal hyperattenuating lesions in which the reference standards were available were included in the study, of which 41 (60%) were confirmed as calcification and 27 (40%) were confirmed as hemorrhage. Sensitivity, specificity, and accuracy of DE CT for the detection of hemorrhage were 96% (95% confidence interval [CI]: 81%, 100%), 100% (95% CI: 91%, 100%), and 99% (95% CI: 92%, 100%) and those of single-energy CT were 74% (95% CI: 54%, 89%), 95% (95% CI: 83%, 99%), and 87% (95% CI: 76%, 94%), respectively. Six of 68 (9%) lesions were classified as indeterminate and three (4%) were misinterpreted with single-energy CT alone and were correctly classified with DE CT.
Conclusion
DE CT by using material decomposition enables accurate differentiation between calcification and hemorrhage in patients presenting for emergency head imaging and can be especially useful in problem-solving complex cases that are difficult to determine based on conventional CT appearance alone. © RSNA, 2016