The Utility of Dual Energy Computed Tomography in Musculoskeletal Imaging

Abstract

The objective of this article is to review the mechanisms, advantages and disadvantages of dual energy computed tomography (DECT) over conventional tomography (CT) in musculoskeletal imaging as DECT provides additional information about tissue composition and artifact reduction. This provides clinical utility in detection of urate crystals, bone marrow edema, reduction of beam hardening metallic artifact, and ligament and tendon analysis.

Keywords: Bone marrow edema; dual energy computed tomography; metallic artifact; musculoskeletal imaging; urate crystals.

Figure 1

(a) A 28-year-old man with gout depicting monosodium urate crystal deposition in the left knee joint on dual energy computed tomography. A cross-sectional (sagittal) color-coded image of the left knee joint using multiplanar reconstruction demonstrates presence of urate deposits (green) in periarticular soft tissue (arrow). The uric acid deposits appear different from osseous structures containing calcium (blue). (b) Volume-rendered color-coded image of both the knee joints depicts presence of monosodium urate crystals in periarticular soft tissue of the left knee joint (arrow). The automated software also calculates the volume of the crystals which was 0.01 cm3 in this patient (as mentioned in figure). The volume-rendered images depict the anatomic relationship between the uric acid deposits and the osseous structures (blue and white).

Figure 2

An 18-year-old female with vertebral compression fracture and bone edema. Cross-sectional (sagittal and coronal) color-coded three-material decomposition (water, fat and calcium) images obtained using virtual noncalcium technique show collapse of L1 vertebral body with presence of bone marrow edema (arrow) as high attenuation area appearing dense green. The region of interest (arrow) shows high mean HU value as compared to the normal (as indicated in L2 vertebra), indicating bone edema.

Figure 3

A 30-year-old man with open reduction and internal fixation of the head and the neck of right humerus. Shown are coronal dual energy computed tomography images reconstructed using monoenergetic spectrum application on a multimodality workstation at monoenergies as mentioned on the respective images (left to right). Reduction of beam hardening artifact is seen at 125 and 190 keV as compared to simulated conventional CT image obtained at 100 kVp (on extreme right). The visibility of lateral chest wall, adjacent soft tissues is markedly improved at higher keV.