Dual-Energy CT: Basic Principles, Technical Approaches, and Applications in Musculoskeletal Imaging (Part 2)

Abstract

In recent years, technological advances have allowed manufacturers to implement dual-energy computed tomography (DECT) on clinical scanners. With its unique ability to differentiate basis materials by their atomic number, DECT has opened new perspectives in imaging. DECT has been successfully used in musculoskeletal imaging with applications ranging from detection, characterization, and quantification of crystal and iron deposits, to simulation of noncalcium (improving the visualization of bone marrow lesions) or noniodine images. Furthermore, the data acquired with DECT can be postprocessed to generate monoenergetic images of varying kiloelectron volts, providing new methods for image contrast optimization as well as metal artifact reduction. The first part of this article reviews the basic principles and technical aspects of DECT including radiation dose considerations. The second part focuses on applications of DECT to musculoskeletal imaging including gout and other crystal-induced arthropathies, virtual noncalcium images for the study of bone marrow lesions, the study of collagenous structures, applications in computed tomography arthrography, as well as the detection of hemosiderin and metal particles.

Dual-Energy CT: New Horizon in Medical Imaging

“…Similarly, synovial hemosiderin deposits can be identified on dual-energy CT in patients with pigmented villonodular synovitis (23). As in intravenously enhanced CT, VNC imaging may be applied to CT arthrography in the musculoskeletal region (23).…”

“…As in intravenously enhanced CT, VNC imaging may be applied to CT arthrography in the musculoskeletal region (23). In the musculoskeletal region, virtual non-calcium imaging may be used to evaluate the bone marrow that is beyond the scope of CT evaluation.…”

“…In the musculoskeletal region, virtual non-calcium imaging may be used to evaluate the bone marrow that is beyond the scope of CT evaluation. Virtual non-calcium imaging subtracts calcium from cancellous bone and allows detection of acute traumatic bone marrow lesions including occult fractures and bone bruises, which cannot be clearly visualized on single-energy CT (232425). Diagnostic performance of virtual non-calcium imaging tends to be better for small appendicular bones than axial skeletons.…”

“…In addition, false-positive results may occur due to the presence of normal red marrow, and other pathologies, such as osteonecrosis or degenerative changes, may mimic post-traumatic bone marrow lesions. A combined review of gray-scale images and color-coded images can facilitate the identification of small attenuation changes within the bone marrow (232425). Of note, automatic color-coded bone marrow segmentation is incomplete, especially in the head region.…”

“…11) (25). In gout, dual-energy CT is particularly useful for cases with unusual locations, negative or inconclusive arthrocentesis, and other concomitant arthropathies, and evaluating total gout burden and treatment-response (23). For complete evaluation, the use of a standardized 4-limb dual-energy CT is suggested.…”