The feasibility of dual-energy CT in differentiation of vertebral compression fractures

Evaluation of Femoral Head Avascular Necrosis With Virtual Noncalcium Dual-Energy Computed Tomography

OBJECTIVE

Our aim was to investigate the effectiveness of the dual-energy computed tomography (DECT) virtual noncalcium (VNCa) technique in avascular necrosis (AVN) for detecting bone marrow edema (BME) and staging.

METHODS

This prospective study included adult patients diagnosed with unilateral or bilateral femoral head AVN between January 2023 and December 2023, who had magnetic resonance imaging (MRI) and DECT. Two participants were excluded from the study due to undergoing surgical procedures during the period between the scans. Two reviewers, blinded to MRI images and clinical data, visually examined color-coded VNCa pictures to assess BME using a binary classification (0 = normal bone marrow, 1 = BME). Same 2 reviewers also used color-coded and nonmapped images to stage AVN in accordance to the "Association for Research on Osseous Circulation" (ARCO) staging system. Interobserver agreements for the visual evaluation and staging were calculated with κ coefficient. Following a visual assessment of BME and the staging of AVN, same 2 reviewers conducted CT density measurements on regions of BME regions utilizing DECT noncalcium images. An independent third investigator (reference standard) utilized MRI, x-ray, and clinical data to confirm the definitive diagnosis and staging of AVN. A P value less than 0.05 was considered statistically significant.

RESULTS

Fifty patients (28 men, 22 women, mean age: 44.2 ± 13.1 years, range: 25-75 years) were included in the final analysis. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the VNCa technique in detecting BME were 96.0%, 94.4%, 97.9%, 89.4%, and 95.6%, respectively, for reviewer 1; and 96.0%, 88.9%, 96.0%, 88.9%, and 94.1%, respectively, for reviewer 2. Interobserver agreement was almost perfect ( κ = 0.84). Both reviewer 1 and reviewer 2 accurately classified 92.7% of the AVNs. The density measurements showed a statistically significant difference ( P = 0.001) between the edema regions and the normal marrow regions. No statistically significant difference was observed in the density measurements of edema regions at different stages ( P = 0.13).

CONCLUSIONS

DECT VNCa technique exhibits excellent performance in detecting BME in hip AVN cases, as well as accurately determining the stage of AVN.

W-DRAG: A joint framework of WGAN with data random augmentation optimized for generative networks for bone marrow edema detection in dual energy CT

Dual-energy computed tomography (CT) is an excellent substitute for identifying bone marrow edema in magnetic resonance imaging. However, it is rarely used in practice owing to its low contrast. To overcome this problem, we constructed a framework based on deep learning techniques to screen for diseases using axial bone images and to identify the local positions of bone lesions. To address the limited availability of labeled samples, we developed a new generative adversarial network (GAN) that extends expressions beyond conventional augmentation (CA) methods based on geometric transformations. We theoretically and experimentally determined that combining the concepts of data augmentation optimized for GAN training (DAG) and Wasserstein GAN yields a considerably stable generation of synthetic images and effectively aligns their distribution with that of real images, thereby achieving a high degree of similarity. The classification model was trained using real and synthetic samples. Consequently, the GAN technique used in the diagnostic test had an improved F1 score of approximately 7.8% compared with CA. The final F1 score was 80.24%, and the recall and precision were 84.3% and 88.7%, respectively. The results obtained using the augmented samples outperformed those obtained using pure real samples without augmentation. In addition, we adopted explainable AI techniques that leverage a class activation map (CAM) and principal component analysis to facilitate visual analysis of the network's results. The framework was designed to suggest an attention map and scattering plot to visually explain the disease predictions of the network.

Photon-counting detector CT - first experiences in the field of musculoskeletal radiology

The introduction of photon-counting detector CT (PCD-CT) marks a remarkable leap in innovation in CT imaging. The new detector technology allows X-rays to be converted directly into an electrical signal without an intermediate step via a scintillation layer and allows the energy of individual photons to be measured. Initial data show high spatial resolution, complete elimination of electronic noise, and steady availability of spectral image data sets. In particular, the new technology shows promise with respect to the imaging of osseous structures. Recently, PCD-CT was implemented in the clinical routine. The aim of this review was to summarize recent studies and to show our first experiences with photon-counting detector technology in the field of musculoskeletal radiology.We performed a literature search using Medline and included a total of 90 articles and reviews that covered recent experimental and clinical experiences with the new technology.In this review, we focus on (1) spatial resolution and delineation of fine anatomic structures, (2) reduction of radiation dose, (3) electronic noise, (4) techniques for metal artifact reduction, and (5) possibilities of spectral imaging. This article provides insight into our first experiences with photon-counting detector technology and shows results and images from experimental and clinical studies. · This review summarizes recent experimental and clinical studies in the field of photon-counting detector CT and musculoskeletal radiology.. · The potential of photon-counting detector technology in the field of musculoskeletal radiology includes improved spatial resolution, reduction in radiation dose, metal artifact reduction, and spectral imaging.. · PCD-CT enables imaging at lower radiation doses while maintaining or even enhancing spatial resolution, crucial for reducing patient exposure, especially in repeated or prolonged imaging scenarios.. · It offers promising results in reducing metal artifacts commonly encountered in orthopedic or dental implants, enhancing the interpretability of adjacent structures in postoperative and follow-up imaging.. · With its ability to routinely acquire spectral data, PCD-CT scans allow for material classification, such as detecting urate crystals in suspected gout or visualizing bone marrow edema, potentially reducing reliance on MRI in certain cases.. Bette S, Risch F, Becker J et al. Photon-counting detector CT - first experiences in the field of musculoskeletal radiology. Fortschr Röntgenstr 2024; DOI 10.1055/a-2312-6914.

Value of third-generation of VNCa dual-energy CT for differentiating diffuse marrow infiltration of multiple myeloma from red bone marrow

This study aims to investigate the ability of bone marrow imaging using third-generation dual-energy computed tomography (CT) virtual noncalcium (VNCa) to differentiate between multiple myeloma (MM) with diffuse bone marrow infiltration and red bone marrow (RBM). Bone marrow aspiration or follow-up results were used as reference. We retrospectively reviewed 188 regions of interests (ROIs) from 21 patients with confirmed MM and diffuse bone marrow infiltrations who underwent VNCa bone marrow imaging between May 2019 and September 2022. At the same time, we obtained 98 ROIs from 11 subjects with RBM for comparative study, and 189 ROIs from 20 subjects with normal yellow bone marrow for the control group. The ROIs were delineated by 2 radiologists independently, the interobservers reproducibility was evaluated by interclass correlation coefficients. The correlation with MRI grade results was analyzed by Spearman correlation coefficient. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal threshold for differentiating between these groups and to assess diagnostic performance. There were statistically significant differences in VNCa CT values of bone marrow among the MM, RBM, and control groups (all P < .001), with values decreasing sequentially. A strong positive rank correlation was observed between normal bone marrow, subgroup MM with moderately and severe bone marrow infiltration divided by MRI and their corresponding CT values (ρ = 0.897, 95%CI: 0.822 to 0.942, P < .001). When the CT value of VNCa bone marrow was 7.15 HU, the area under the curve (AUC) value for differentiating RBM and MM was 0.723, with a sensitivity of 50.5% and a specificity of 89.8%. When distinguishing severe bone marrow infiltration of MM from RBM, the AUC value was 0.80 with a sensitivity 70.9% and a specificity 78.9%. The AUC values for MM, RBM, and the combined group compared to the control group were all >0.99, with all diagnostic sensitivity and specificity exceeding 95%. VNCa bone marrow imaging using third-generation dual-energy CT accurately differentiates MM lesions from normal bone marrow or RBM. It demonstrates superior diagnostic performance in distinguishing RBM from MM with diffuse bone marrow infiltration.

Updates on the Applications of Spectral Computed Tomography for Musculoskeletal Imaging

Spectral CT represents a novel imaging approach that can noninvasively visualize, quantify, and characterize many musculoskeletal pathologies. This modality has revolutionized the field of radiology by capturing CT attenuation data across multiple energy levels and offering superior tissue characterization while potentially minimizing radiation exposure compared to traditional enhanced CT scans. Despite MRI being the preferred imaging method for many musculoskeletal conditions, it is not viable for some patients. Moreover, this technique is time-consuming, costly, and has limited availability in many healthcare settings. Thus, spectral CT has a considerable role in improving the diagnosis, characterization, and treatment of gout, inflammatory arthropathies, degenerative disc disease, osteoporosis, occult fractures, malignancies, ligamentous injuries, and other bone-marrow pathologies. This comprehensive review will delve into the diverse capabilities of dual-energy CT, a subset of spectral CT, in addressing these musculoskeletal conditions and explore potential future avenues for its integration into clinical practice.

Dual-energy CT applications in musculoskeletal disorders

Dual-energy CT (DECT) is an exciting application in CT technology conferring many advantages over conventional single-energy CT at no additional with comparable radiation dose to the patient. Various emerging and increasingly established clinical DECT applications in musculoskeletal (MSK) imaging such as bone marrow oedema detection, metal artefact reduction, monosodium urate analysis, and collagen analysis for ligamentous, meniscal, and disc injuries are made possible through its advanced DECT post-processing capabilities. These provide superior information on tissue composition, artefact reduction and image optimization. Newer DECT applications to evaluate fat fraction for sarcopenia, Rho/Z application for soft tissue calcification differentiation, 3D rendering, and AI integration are being assessed for future use. In this article, we will discuss the established and developing applications of DECT in the setting of MSK radiology as well as the basic principles of DECT which facilitate them.

Role of biophysical stimulation in multimodal management of vertebral compression fractures

Raised life expectancy and aging of the general population are associated with an increased concern for fragility fractures due to factors such as osteoporosis, reduced bone density, and an higher risk of falls. Among these, the most frequent are vertebral compression fractures (VCF), which can be clinically occult. Once the diagnosis is made, generally thorough antero-posterior and lateral views of the affected spine at the radiographs, a comprehensive workup to assess the presence of a metabolic bone disease or secondary causes of osteoporosis and bone frailty is required. Treatment uses a multimodal management consisting of a combination of brace, pain management, bone metabolism evaluation, osteoporosis medication and has recently incorporated biophysical stimulation, a noninvasive technique that uses induced electric stimulation to improve bone recovery through the direct and indirect upregulation of bone morphogenic proteins, stimulating bone formation and remodeling. It contributes to the effectiveness of the therapy, promoting accelerated healing, supporting the reduction of bed rest and pain medications, improving patients' quality of life, and reducing the risk to undergo surgery in patients affected by VCFs. Therefore, the aim of this review is to outline the fundamental concepts of multimodal treatment for VCF, as well as the present function and significance of biophysical stimulation in the treatment of VCF patients.

Dual-Energy Computed Tomography and Beyond: Musculoskeletal System

Traditional monoenergetic computed tomography (CT) scans in musculoskeletal imaging provide excellent detail of bones but are limited in the evaluation of soft tissues. Dual-energy CT (DECT) overcomes many of the traditional limitations of CT and offers anatomical details previously seen only on MR imaging. In addition, DECT has benefits in the evaluation and characterization of arthropathies, bone marrow edema, and collagen applications in the evaluation of tendons, ligaments, and vertebral discs. There is current ongoing research in the application of DECT in arthrography and bone mineral density calculation.

[Contemporary imaging examinations for (suspected) stress fractures]

Stress fractures belong to the group of atraumatic fractures. A low-impact and repetitive load is the underlying cause and no fracture would occur under physiological circumstances. The conventional X‑ray examination remains the initial imaging modality when a stress fracture is suspected. In contrast, magnetic resonance imaging (MRI) is the gold standard and is also used to rule out other pathological changes. Computed tomography (CT) should be included if the MRI findings are unclear. New techniques, such as dual energy computed tomography (DECT) and magnetic resonance bone imaging (MR bone) should be used more frequently in practice in the future and become increasingly more important for the correct diagnosis.

ACR Appropriateness Criteria® Management of Vertebral Compression Fractures: 2022 Update

Vertebral compression fractures (VCFs) can have a variety of etiologies, including trauma, osteoporosis, or neoplastic infiltration. Osteoporosis related fractures are the most common cause of VCFs and have a high prevalence among all postmenopausal women with increasing incidence in similarly aged men. Trauma is the most common etiology in those >50 years of age. However, many cancers, such as breast, prostate, thyroid, and lung, have a propensity to metastasize to bone, which can lead to malignant VCFs. Indeed, the spine is third most common site of metastases after lung and liver. In addition, primary tumors of bone and lymphoproliferative diseases such as lymphoma and multiple myeloma can be the cause of malignant VCFs. Although patient clinical history could help raising suspicion for a particular disorder, the characterization of VCFs is usually referred to diagnostic imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Dual energy CT in musculoskeletal applications beyond crystal imaging: bone marrow maps and metal artifact reduction

Dual energy CT (DECT) is becoming increasingly popular and valuable in the domain of musculoskeletal imaging. Gout maps and crystal detection have been predominant indications for about a decade. Other important indications of bone marrow maps and metal artifact reduction are also frequent with added advantages of detection and characterization of bone marrow lesions similar to MR imaging and diagnosis of hardware related complications, respectively. This article discusses technical considerations and physics of DECT imaging and its role in musculoskeletal indications apart from crystal imaging with respective case examples and review of the related literature. DECT pitfalls in these domains are also highlighted and the reader can gain knowledge of above concepts for prudent use of DECT in their musculoskeletal and general practices.

Management of vertebral compression fractures: the role of dual-energy CT in clinical practice

PURPOSE

To evaluate the role of dual-energy computed tomography (DECT) in the management of vertebral compression fractures in clinical practice.

MATERIALS AND METHODS

This retrospective IRB-approved study included 497 consecutive patients with suspected acute vertebral fractures, imaged either by DECT (group 1) or MRI (group 2) before vertebroplasty. The site, number and type of fractures at imaging findings, and clinical outcome based on any change in pain (DELTA-VAS), before (VAS-pre) and after treatment (VAS-post), were determined and compared. Two radiologists evaluated DECT and MRI images (15 and 5 years of experience, respectively), and inter-observer and intra-observer agreement were calculated using k statistics.

RESULTS

Both in the control group (n = 124) and in the group of patients treated by vertebroplasty (n = 373), the clinical outcome was not influenced by the imaging approach adopted, with a DELTA-VAS of 5.45 and 6.42 in the DECT group and 5.12 and 6.65 in the MRI group (p = 0.326; p = 0.44). In the group of treated patients, sex, age, lumbar fractures, multiple fractures, previous fractures, Genant grade, involvement of anterior apex or superior endplates, and increased spinal curvatures were similar (p = ns); however, dorsal fractures were more prevalent in group 1 (p = 0.0197). Before treatment, the mean VAS-pre was 8.74 in group 1 (DECT) and 8.65 in group 2 (MRI) (p = 0.301), whereas after treatment, the mean VAS-post value was 2.32 in group 1 (p = 0.0001), and 2.00 in group 2 (p = 0.0001). The DELTA-VAS was 6.42 in the group of patients imaged using DECT and 6.65 in the group imaged using MRI (p = 0.326). Inter-observer and intra-observer agreement were 0.85 and 0.89 for DECT, and 0.88 and 0.91 for MRI, respectively.

CONCLUSION

The outcome of vertebral compression fracture management was no different between the two groups of patients studied.

Quantification of bone marrow edema using dual-energy CT at fracture sites in trauma

PURPOSE

The purpose of our study was to analyze the change in water and fat density within the bone marrow using the GE Revolution dual-energy computed tomography (DECT) platform using two-material decomposition analyses at extremity, spine, and pelvic fracture sites compared to normal bone marrow at equivalent anatomic sites in adult patients who sustained blunt trauma.

METHODS

This retrospective study included 26 consecutive adults who sustained blunt torso trauma and an acute fracture of the thoracolumbar vertebral body, pelvis, or upper and lower extremities with a total of 32 fractures evaluated. Two-material decomposition images were analyzed for quantitative analysis. Statistical analysis was performed using the paired t-test and Shapiro-Wilk test for normality.

RESULTS

There were statistically significant differences in the water and fat densities in the bone marrow at the site of an extremity, vertebral body, or pelvic fracture when compared to the normal anatomic equivalent (p < 0.01).

CONCLUSION

In this preliminary study, DECT basis material images, using water (calcium) and fat (calcium) decomposition illustrated significant differences in water and fat content between fracture sites and normal bone in a variety of anatomical sites.

Cortical step sign in spinal clearance on trauma computed tomography – Indicator of acute thoracolumbar compression fracture

Introduction

Differentiating an acute from chronic compression fracture of the thoracolumbar (TL) spine can pose a dilemma for radiologists interpreting spinal imaging following trauma. Mild wedging of the vertebrae can be due to spondylosis or osteoporosis, whilst acute simple compression fractures may not always be associated with loss of body height. In this observational study, we hypothesize that the presence of a vertebral body cortical step is a reliable sign of an acute compression fracture on Computed Tomography (CT) scans.

Methods

In a retrospective review of thoracolumbar CT scans following trauma, two observers analysed for the presence of a cortical step at the anterior or posterior vertebral body cortex, fracture morphology and associated injuries. A ‘cortical step’ is defined as a break of hyperdense cortex on CT scans, intervening non-sclerosed trabecular bone, and sharp overlap of the underlying cortex. MRI of the spine was used as gold standard.

Results

187 consecutive CT scans over 2 years were assessed. Sensitivity, specificity and accuracy of cortical step sign were 100%, 90.2% and 97% in diagnosing an acute thoracolumbar compression fracture, respectively. The interobserver reliability was high (kappa = 0.97). False positive cortical step was seen in Kummel’s disease and large Schmorl’s nodule.

Conclusion

Our results demonstrate high sensitivity and specificity of ‘cortical step sign’ in diagnosing acute vertebral body compression fractures of TL spine on CT scans in patients with trauma. This sign can be useful to radiologists for safe clearance of the thoracolumbar spine following trauma, helping distinguish acute trauma from chronic causes of vertebral body height loss.

Visualizing patterns of intervertebral disc damage with dual-energy computed tomography: assessment of diagnostic accuracy in an ex vivo spine biophantom

Background

Previously, dual-energy computed tomography (DECT) has been established for imaging spinal fractures as an alternative modality to magnetic resonance imaging (MRI).

Purpose

To analyze the diagnostic accuracy of DECT in visualizing intervertebral disc (IVD) damage.

Material and Methods

The lumbar spine of a Great Dane dog was used as an ex vivo biophantom. DECT was performed as sequential volume technique on a single-source CT scanner. IVDs were imaged before and after an injection of sodium chloride solution and after anterior discectomy in single-source sequential volume DECT technique using 80 and 135 kVp. Chondroitin/Collagen maps (cMaps) were reconstructed at 1 mm and compared with standard CT. Standardized regions of interest (ROI) were placed in the anterior anulus fibrosus, nucleus pulposus, and other sites. Three blinded readers classified all images as intact disc, nucleus lesion, or anulus lesion. Additionally, clinical examples from patients with IVD lesions were retrospectively identified from the radiological database.

Results

Interrater reliability was almost perfect with a Fleiss kappa of 0.833 (95% confidence interval [CI] 0.83–0.835) for DECT, compared with 0.780 (95% CI 0.778–0.782) for standard CT. For overall detection accuracy of IVD, DECT achieved 91.0% sensitivity (95% CI 83.6–95.8) and 92.0% specificity (95% CI 80.8–97.8). Standard CT showed 91.0% sensitivity (95% CI 83.6–95.8) and 78.0% specificity (95% CI 64.0–88.5).

Conclusion

DECT reliably identified IVD damage in an ex vivo biophantom. Clinical examples of patients with different lesions illustrate the accurate depiction of IVD microstructure. These data emphasize the diagnostic potential of DECT cMaps.

Dual-energy CT-generated bone marrow oedema maps improve timely visualisation and recognition of acute lower extremity fractures

AIM

To assesses whether utilising bone marrow oedema (BMO) maps improved fracture read times and reader confidence in a large series of acute lower extremity trauma dual-energy computed tomography (DECT) studies.

MATERIALS AND METHODS

One hundred and six DECT studies, including 60 fracture cases and 46 non-fracture cases, were evaluated retrospectively in this cross-sectional study. Three-dimensional (3D) BMO maps were generated for each study and coded to display skeletal anatomy in blue and marrow oedema in green. Studies were interpreted by two readers in two timed stages (without and with BMO maps). Readers identified the number, anatomical location, and comminution of fractures. Reader confidence (five-point Likert scale) for fracture identification and anatomical regions where oedema was present was also recorded.

RESULTS

Decreased read times (p<0.01) were observed when readers utilised BMO maps for their fracture search. The presence of oedema on BMO maps corresponded with associated fracture in 75.7% reads. No differences in reader confidence were observed as a result of using this BMO-guided technique (>95%, 5/5 for both readers with and without the aid of BMO maps).

CONCLUSIONS

DECT BMO maps improve the speed of radiological identification of suspected acute lower extremity fractures with preserved reader confidence. It may help emergent detection of fractures, important for patient management and outcomes.

Assessment of thoracic disk herniation by using virtual noncalcium dual-energy CT in comparison with standard grayscale CT

Objectives

To determine the diagnostic accuracy of dual-energy CT (DECT) virtual noncalcium (VNCa) reconstructions for assessing thoracic disk herniation compared to standard grayscale CT.

Methods

In this retrospective study, 87 patients (1131 intervertebral disks; mean age, 66 years; 47 women) who underwent third-generation dual-source DECT and 3.0-T MRI within 3 weeks between November 2016 and April 2020 were included. Five blinded radiologists analyzed standard DECT and color-coded VNCa images after a time interval of 8 weeks for the presence and degree of thoracic disk herniation and spinal nerve root impingement. Consensus reading of independently evaluated MRI series served as the reference standard, assessed by two separate experienced readers. Additionally, image ratings were carried out by using 5-point Likert scales.

Results

MRI revealed a total of 133 herniated thoracic disks. Color-coded VNCa images yielded higher overall sensitivity (624/665 [94%; 95% CI, 0.89–0.96] vs 485/665 [73%; 95% CI, 0.67–0.80]), specificity (4775/4990 [96%; 95% CI, 0.90–0.98] vs 4066/4990 [82%; 95% CI, 0.79–0.84]), and accuracy (5399/5655 [96%; 95% CI, 0.93–0.98] vs 4551/5655 [81%; 95% CI, 0.74–0.86]) for the assessment of thoracic disk herniation compared to standard CT (all p < .001). Interrater agreement was excellent for VNCa and fair for standard CT (ϰ = 0.82 vs 0.37; p < .001). In addition, VNCa imaging achieved higher scores regarding diagnostic confidence, image quality, and noise compared to standard CT (all p < .001).

Conclusions

Color-coded VNCa imaging yielded substantially higher diagnostic accuracy and confidence for assessing thoracic disk herniation compared to standard CT.

Key Points

• Color-coded VNCa reconstructions derived from third-generation dual-source dual-energy CT yielded significantly higher diagnostic accuracy for the assessment of thoracic disk herniation and spinal nerve root impingement compared to standard grayscale CT.

• VNCa imaging provided higher diagnostic confidence and image quality at lower noise levels compared to standard grayscale CT.

• Color-coded VNCa images may potentially serve as a viable imaging alternative to MRI under circumstances where MRI is unavailable or contraindicated.

Detection of Bone Marrow Edema in Patients with Osteoid Osteoma Using Three-Material Decomposition with Dual-Layer Spectral CT

The aim of this study is to assess whether perifocal bone marrow edema (BME) in patients with osteoid osteoma (OO) can be accurately detected on dual-layer spectral CT (DLCT) with three-material decomposition. To that end, 18 patients with OO (25.33 ± 12.44 years; 7 females) were pairwise-matched with 18 patients (26.72 ± 9.65 years; 9 females) admitted for suspected pathologies other than OO in the same anatomic location but negative imaging findings. All patients were examined with DLCT and MRI. DLCT data was decomposed into hydroxyapatite and water- and fat-equivalent volume fraction maps. Two radiologists assessed DLCT-based volume fraction maps for the presence of perifocal BME, using a Likert scale (1 = no edema; 2 = likely no edema; 3 = likely edema; 4 = edema). Accuracy, sensitivity, and specificity for the detection of BME on DLCT were analyzed using MR findings as standard of reference. For the detection of BME in patients with OO, DLCT showed a sensitivity of 0.92, a specificity of 0.94, and an accuracy of 0.92 for both radiologists. Interreader agreement for the assessment of BME with DLCT was substantial (weighted κ = 0.78; 95% CI, 0.59, 0.94). DLCT with material-specific volume fraction maps allowed accurate detection of BME in patients with OO. This may spare patients additional examinations and facilitate the diagnosis of OO.

Dual-Energy Computed Tomography in Spine Fractures: A Systematic Review and Meta-Analysis

BACKGROUND

The purpose of this study was to perform a systematic literature review and meta-analysis to evaluate the sensitivity, specificity, and accuracy of dual-energy computed tomography (DE-CT) of bone marrow edema and disc edema in spine injuries.In vertebral injuries, prompt diagnosis is essential to avoid any delays in treatment. Conventional radiography may only reveal indirect signs of fractures, such as when it is displaced. Therefore, to detect the presence of bone marrow or disc edemas, adjunctive tools are required, such as magnetic resonance imaging (MRI) or DE-CT.

METHODS

Search terms included ((DECT) OR (DE-CT) OR (dual-energy CT) OR "Dual energy CT" OR (dual-energy computed tomography) OR (dual energy computed tomography)) AND ((spine) OR (vertebral)), and the PubMed, EMBASE, and MEDLINE databases and the Cochrane Library and Google were used. We found 1233 articles on our preliminary search, but only 13 articles met all criteria. Data were extracted to calculate the pooled sensitivity, specificity, and diagnostic odds ratio for analysis using R software.

RESULTS

Within the 13 studies, 515 patients, 3335 vertebrae, and 926 acute fractures (27.8%) defined by MRI were included. The largest cohort included 76 patients with 774 vertebrae. In 12 publications, MRI was reported for comparison. For DE-CT, the overall sensitivity was 86.2% with a specificity of 91.2% and accuracy of 89.3%. Furthermore, 5 studies reported the accuracy of CT with an overall sensitivity of 81.3%, specificity of 80.7%, and accuracy with 80.9%. Significant differences were found for specificity (P < .001) and accuracy (P = .023). However, significant interobserver differences were reported.

CONCLUSIONS

DE-CT seems to be a promising diagnostic tool to detect bone marrow and disc edemas, which can potentially replace the current gold standard, the MRI.

LEVEL OF EVIDENCE

2.

CLINICAL RELEVANCE

This study shows that DE-CT seems to be a promising diagnostic tool with an accuracy of 89.3%.

DECT in Detection of Vertebral Fracture-associated Bone Marrow Edema: A Systematic Review and Meta-Analysis with Emphasis on Technical and Imaging Interpretation Parameters

Background Dual-energy CT (DECT) shows promising performance in detecting bone marrow edema (BME) associated with vertebral body fractures. However, the optimal technical and image interpretation parameters are not well described. Purpose To conduct a systematic review and meta-analysis to determine the diagnostic performance of DECT in detecting BME associated with vertebral fractures (VFs), using different technical and image interpretation parameters, compared with MRI as the reference standard. Materials and Methods A systematic literature search was performed on July 9, 2020, to identify studies evaluating DECT performance for in vivo detection of vertebral BME. A random-effects model was used to derive estimates of the diagnostic accuracy parameters of DECT. The impact of relevant covariates in technical, image interpretation, and study design parameters on the diagnostic performance of DECT was investigated using subgroup analyses. Results Seventeen studies (with 742 of 2468 vertebrae with BME at MRI) met inclusion criteria. Pooled estimates of sensitivity, specificity, and area under the curve of DECT for vertebral body BME were 89% (95% CI: 84%, 92%), 96% (95% CI: 92%, 98%), and 96% (95% CI: 94%, 97%), respectively. Single-source consecutive scanning showed poor specificity (78%) compared with the dual-source technique (98%, P < .001). Specificity was higher using bone and soft-tissue kernels (98%) compared with using only soft-tissue kernels (90%, P = .001). Qualitative assessment had a better specificity (97%) versus quantitative assessment (90%) of DECT images (P = .01). Experienced readers showed considerably higher specificity (96%) compared with trainees (79%, P = .01). DECT sensitivity improved using a higher difference between low- and high-energy spectra (90% vs 83%, P = .04). Conclusion Given its high specificity, the detection of vertebral bone marrow edema with dual-energy CT (DECT) associated with vertebral fracture may obviate confirmatory MRI in an emergency setting. Technical parameters, such as the dual-source technique, both bone and soft-tissue kernels, and qualitative assessment by experienced readers, can ensure the high specificity of DECT. © RSNA, 2021 Online supplemental material is available for this article.

Dual-Layer Detector CT With Virtual Noncalcium Imaging: Diagnostic Performance in Patients With Suspected Wrist Fractures

OBJECTIVE. The purpose of this study was to evaluate the diagnostic utility of dual-layer CT (DLCT) for evaluating wrist injuries and to compare it with MRI. MATERIALS AND METHODS. The cases of 62 patients with suspected wrist fractures who underwent imaging with both DLCT and MRI from January 2018 through February 2019 were retrospectively reviewed. By means of a calcium suppression algorithm, virtual noncalcium (VNCa) image reconstruction was performed, and the images were reviewed by two readers to identify fractures, bone contusions, and nontraumatic lesions in the radius, ulna, and carpal bones. Sensitivity, specificity, PPV, and NPV were calculated and compared between standard CT and VNCa images with a combination of standard CT and MRI as the reference standard. RESULTS. Use of DLCT with VNCa reconstruction increased the sensitivity of diagnosis of fractures in the radius and carpal bones over that of standard CT alone; occult fractures were detected that were not seen with standard CT. The sensitivity and specificity for detecting radius fracture were 98.1% and 93.8% for DLCT and 96.3% and 93.8% for standard CT. For detecting carpal bone fracture, sensitivity and specificity were 100% and 98.9% for DLCT and 93.8% and 100% for standard CT. VNCa reconstruction also had good diagnostic accuracy with regard to diagnosing nonfracture bone contusions in carpal bones. The accuracy was comparable to that of MRI with sensitivity of 92.9% and specificity of 94.5%. Interreader agreement in interpreting VNCa images was generally good to excellent. CONCLUSION. DLCT with VNCa reconstruction is a promising tool for identifying occult wrist fractures and nonfracture contusion injuries in patients with wrist trauma.

Dual energy computed tomography evaluation of skeletal traumas

Skeletal traumas are among the most common routine challenges faced by Emergency Radiologists, in particular in case of radiographically occult nondisplaced fractures or in case of soft tissue injuries. With the development of Dual Energy Computed Tomography (DECT) technology, new post-processing applications have gained a useful diagnostic role in many fields of musculoskeletal imaging including acute skeletal trauma imaging. In addition to conventional CT images, DECT allows for the generation of virtual calcium-suppressed images subtracting calcium from unenhanced CT images based on the fact that material attenuation varies at different energy levels. In this way, virtual-non-calcium (VNC) images can precisely characterize traumatic bone marrow edema in both axial and appendicular skeleton, facilitating prompt clinical decision, especially when magnetic resonance method is contraindicated or unavailable. Other DECT emerging applications in the trauma setting include metal artifact reduction and collagen mapping for the evaluation of injuries affecting ligament, tendon, and intervertebral disk. This review focuses on the basic principles of DECT and related post-processing algorithms, highlighting the current advantages and limitations of these new imaging advances in the Emergency Department related to skeletal traumas.

Dual-energy CT in musculoskeletal trauma

Dual-energy computed tomography (DECT) combines the advantages of conventional CT with the ability to detect bone marrow oedema (BMO), which was previously limited to magnetic resonance imaging (MRI). By analysing DECT virtual non-calcium (VNCa) maps, radiologists can improve the detection of subtle and occult fractures and approximate the acuity/healing of fractures of indeterminate age. This review highlights the role of DECT in the assessment of musculoskeletal trauma, particularly among elderly, post-menopausal women and those at risk for osteoporosis. DECT is especially useful in investigating trabecular bone predominant regions (e.g., vertebral bodies, pelvis, hip, and long bone metaphyses) for stress (i.e., fatigue or insufficiency) and fragility fractures. CT is often performed first due to its increased availability, especially in the emergency setting, shorter imaging duration, and possible patient contraindications to magnetic resonance imaging (MRI). By enabling BMO detection, DECT may have a role in triaging patients for definitive MRI assessment. Understanding the role of anatomical, pathological, and patient factors in image interpretation can improve radiologist adoption of DECT, increase diagnostic confidence, and improve patient management.

Added value of color-coded virtual non-calcium dual-energy CT in the detection of acute knee fractures in non-radiology inexpert readers

PURPOSE

To evaluated the added value of dual-energy CT (DECT) virtual non-calcium (VNCa) protocol on conventional CT in the detection of acute knee fractures in non-radiology inexpert readers.

METHOD

One hundred fifty-six patients (mean age, 51.97 years; age range, 17-86 years) with knee trauma, who underwent DECT and MRI within 3 days between April 2017 and October 2018, were retrospectively analyzed. Three readers (intern, 1st-year general surgery resident, 1st-year emergency medicine resident) independently analyzed CT alone and then with the additional color-coded DECT VNCa for fractures. A board-certified radiologist, analyzed CT and MRI series to define the reference standard. Sensitivity, specificity, and AUC were compared between the two reading sessions.

RESULTS

Fifty-seven patients had acute fractures and 99 had no fractures. Thirteen of 57 fractures were nondisplaced. The additional use of VNCa images significantly increased the mean AUC (reader 1: 0.813 vs. 0.919; reader 2: 0.842 vs. 0.930; reader 3: 0.837 vs. 0.921; P < 0.05). When only nondisplaced fractures included, the mean AUC was more increased in the combined analysis of CT and DECT VNCa (reader 1: 0.521 vs. 0.916; reader 2: 0.542 vs. 0.926; reader 3: 0.575 vs. 0.926; P <  .01). Sensitivity increased by 15 %-20 % in total fracture group and by 69 %-77 % in nondisplaced fracture group over that with CT alone when both CT and DECT VNCa were used. Specificity did not differ significantly.

CONCLUSIONS

The additional use of color-coded DECT VNCa protocol to conventional CT improved diagnostic performance in detecting acute knee fractures for inexperienced non-radiology readers.

Diagnostic accuracy of dual-energy CT for detection of bone marrow lesions in the subacutely injured knee with MRI as reference method

BACKGROUND

Dual-energy computer tomography (DECT) can detect post-traumatic bone marrow lesions. Prospective studies of the knee with large numbers of participants and intra-observer agreement assessment are limited.

PURPOSE

To investigate the diagnostic accuracy of DECT in detecting bone marrow lesions as well as estimating the bone marrow lesion volume in patients with suspected anterior cruciate ligament trauma with magnetic resonance imaging (MRI) as reference standard.

MATERIAL AND METHODS

Forty-eight consecutive patients with suspected anterior cruciate ligament injury were imaged bilaterally with DECT within a mean of 25 days (range 4-55 days) following injury and MRI within seven days of DECT. Two readers analyzed DECT virtual non-calcium-blinded images. Consensus MRI was reference standard. Intra- and inter-observer agreement were determined using weighted kappa statistics. Sensitivity, specificity, and negative and positive predictive values were calculated. Bone marrow lesion volumes were measured; for comparison, intra-class correlation coefficient was used.

RESULTS

The 48 patients (26 men, 22 women; mean age 23 years, age range 15-37 years) were imaged bilaterally yielding 52 knees with bone marrow lesions, of which 44 were in the femur and 41 were in the tibia. Intra- and inter-observer agreement to detect bone marrow lesions was moderate and fair to moderate (κ 0.54-0.66, 95% confidence interval [CI] 0.39-0.80 and 0.37-0.41, 95% CI 0.20-0.57) and overall sensitivity and specificity were 70.1% and 69.1%, respectively. Positive and negative predictive values were 72.9% and 66.1%, respectively. Bone marrow lesion volumes showed excellent intra- and inter-observer agreement (0.83-0.91, 95% CI 0.74-0.94 and 0.76-0.78, 95% CI 0.57-0.87).

CONCLUSION

The diagnostic performance of DECT to detect bone marrow lesions in the subacutely injured knee was moderate with intra- and inter-observer agreement ranging from moderate to substantial and fair to moderate. Bone marrow lesion volume correlation was excellent.

Single-source dual-energy computed tomography for the detection of bone marrow lesions: impact of iterative reconstruction and algorithms

PURPOSE

To compare the diagnostic performance of different reconstruction algorithms of single-source dual-energy computed tomography (DECT) for the detection of bone marrow lesions (BML) in patients with vertebral compression fracture using MRI as the standard of reference.

MATERIAL AND METHODS

Seventeen patients with an age over 50 who underwent single-source DECT of the spine were included. The raw data (RD) were reconstructed using filtered back-projection (FBP) and iterative reconstruction (IR) with three iteration levels (IR1-IR3). Bone marrow images were generated using a three-material decomposition (3MD) and a two-material decomposition (2MD) algorithm and an RD-based approach. Three blinded readers scored the images for image quality and the presence of bone marrow lesions (BML). Only vertebrae with height loss were included. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The different reconstructions were compared using Dunn's multiple comparison test.

RESULTS

Thirty-nine vertebrae were included. IR(1-3) showed superior sensitivity (87.5%) compared to FBP (75%) using 3MD but was comparable to RD (83.3%). All 2MD images were inferior (sensitivity < 38%). The image quality score was significantly higher for 3MD-IR(1-3) compared to 3MD-FBP (p < 0.0001) and all 2MD data sets (p < 0.03). This pattern was also supported by the SNR and CNR measurements. RD showed no significant improvement compared to IR.

CONCLUSION

The image quality of bone marrow images acquired with DECT can be improved by using IR compared with FBP. RD-based reconstruction does not offer significant improvement over image data-based reconstruction. 2MD algorithms are not suitable for BML detection.

Diagnostic accuracy of dual energy CT in the assessment of traumatic bone marrow edema of lower limb and its correlation with MRI

Background:

Bone marrow edema is assumed to be caused as a result of trabecular microfractures that are detected by MRI. As MRI is not widely available in countries like India, this study aims to encourage the use of DECT in detection of bone edema as evidence with comparable efficiency to MRI.

Aim:

To assess the diagnostic accuracy of dual-energy CT in detecting bone marrow edema in patients of trauma of lower limb and correlate it with MRI.

Setting and Design:

It is a cross-sectional study.

Materials and Methods:

The study included 40 patients of age 15–70 years irrespective of sex. All the patients of lower extremity trauma underwent DECT and MRI evaluation after clinical evaluation. All the images were postprocessed on a work station and were further evaluated by a radiologist.

Results:

Mean attenuation at fractured site observed by Dual energy CT was found to be significantly higher as compared to that at adjacent site (170.75 ± 33.99 vs. 19.73 ± 22.50 HU). The sensitivity and specificity of dual energy CT as compared to MRI in detecting bone marrow edema were 94.1% and 91.3%, respectively. Of the 40 cases enrolled in the study, agreement of MRI and Dual energy CT was observed in 37 (92.5%).

Conclusion:

Dual energy CT can be an effective alternative to MRI in the detection of bone marrow edema in patients of lower limb trauma. Dual energy CT can also be used in patients in whom MRI is contraindicated.

Fast kilovoltage (KV)-switching dual-energy computed tomography hydroxyapatite (HAP)-water decomposition technique for identifying bone marrow edema in vertebral compression fractures

Background

Hydroxyapatite (HAP) is the main component of bone mineral. The utility of using HAP-water decomposition technique with fast kilovoltage (KV)-switching dual-energy computed tomography (DECT) to detect abnormal edema in vertebral compression fractures (VCFs) has not been widely reported.

Methods

A total of 31 consecutive patients with 80 VCFs who underwent DECT and magnetic resonance imaging (MRI) of the spine were retrospectively enrolled in our study between October 2018 and January 2019. VCFs in MR examinations served as the standard of reference. Two radiologists blindly and independently evaluated color-coded overlay virtual nonhydroxyapatite (VNHAP) images for the presence of abnormal edema. The inter-reader agreement, specificity, sensitivity, accuracy, and predictive values of VNHAP images for edema detection were calculated. The diagnostic accuracy of two readers was compared using McNemar's test. Two additional radiologists performed a quantitative analysis on VNHAP images, receiver operating characteristic (ROC) curve analysis was conducted, and the threshold was calculated.

Results

MRI depicted 45 edematous and 35 nonedematous VCFs. For visual analysis, the VNHAP technique showed a sensitivity of 93.3%, a specificity of 97.1%, a positive predictive value (PPV) of 97.7%, a negative predictive value (NPV) of 91.9%, and an accuracy of 95.0%. The inter-reader agreement was almost perfect (k=0.90). The diagnostic accuracy of the two readers showed no significant differences in the assessment of VNHAP images (P=1.00). Significant differences in CT numbers between vertebrae with and without bone marrow edema were found by quantitative analysis (P<0.01). The area under the curve (AUC) of the VNHAP images was estimated to be 0.917. The threshold of 1,003.2 mg/cm³ yielded a sensitivity of 88.9% and a specificity of 82.9% for the differentiation of fresh and old VCFs.

Conclusions

Fast KV-switching DECT HAP-water decomposition technique had excellent diagnostic performance for identifying acute and chronic VCFs in visual and quantitative analyses.

ACR Appropriateness Criteria® Management of Vertebral Compression Fractures

Vertebral compression fractures (VCFs) have various causes, including osteoporosis, neoplasms, and acute trauma. As painful VCFs may contribute to general physical deconditioning, management of painful VCFs has the potential for improving quality of life and preventing superimposed medical complications. Various imaging modalities can be used to evaluate a VCF to help determine the etiology and guide intervention. The first-line treatment of painful VCFs has been nonoperative or conservative management as most VCFs show gradual improvement in pain over 2 to 12 weeks, with variable return of function. There is evidence that vertebral augmentation (VA) is associated with better pain relief and improved functional outcomes compared to conservative therapy for osteoporotic VCFs. A multidisciplinary approach is necessary for the management of painful pathologic VCFs, with management strategies including medications to affect bone turnover, radiation therapy, and interventions such as VA and percutaneous thermal ablation to alleviate symptoms. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Blunt Thoracolumbar-Spine Trauma Evaluation in the Emergency Department: A Meta-Analysis of Diagnostic Accuracy for History, Physical Examination, and Imaging

BACKGROUND

Delayed diagnoses of unstable thoracolumbar spine (TL-spine) fractures can result in neurologic deficits and avoidable pain, so it is important for clinicians to reach prompt diagnostic decisions. There are no validated decision aids for determining which trauma patients warrant TL-spine imaging.

OBJECTIVE

Our aim was to quantify the diagnostic accuracy of the injury mechanism, physical examination, associated injuries, clinical decision aids, and imaging for evaluating blunt TL-spine trauma patients.

METHODS

A search strategy for studies including adult blunt TL-spine trauma using PubMed, Embase, Scopus, CENTRAL, Cochrane Database of Systematic Reviews, and ClinicalTrials.gov was performed. Excluded studies lacked data to construct 2 × 2 tables, were duplicates, were not primary research, did not focus on blunt trauma, examined associated injuries without any utility in identifying TL-spine injuries, only studied cervical-spine fractures, were non-English, had a pediatric setting, or were cadaver/autopsy reports. Risk of bias was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies. Diagnostic predictors were analyzed with a meta-analysis of sensitivity, specificity, and likelihood ratios.

RESULTS

In blunt trauma patients in the emergency department, the weighted pretest probability of a TL-spine fracture was 15%. The estimates for detection of TL-spine fractures with plain film were: positive likelihood ratio (+LR) = 25.0 (95% confidence interval [CI] 4.1-152.2; I² = 94%; p < 0.001) and negative likelihood ratio (-LR) = 0.43 (95% CI 0.32-0.59; I² = 84%; p < 0.001), and for computed tomography (CT) were: +LR = 81.1 (95% CI 14.1-467.9; I² = 87%; p < 0.001) and -LR = 0.04 (95% CI 0.02-0.08; I² = 23%; p = 0.26).

CONCLUSIONS

CT is more accurate than plain films for detecting TL-spine fractures. Injury mechanism, physical examination, and associated injuries alone are not accurate to rule-in or rule-out TL-spine fractures.

Axial Spondyloarthritis: Dual-Energy Virtual Noncalcium CT in the Detection of Bone Marrow Edema in the Sacroiliac Joints

Purpose To determine the diagnostic performance of dual-energy virtual noncalcium (VNCa) CT in the detection of bone marrow edema in study participants with sacroiliitis associated with axial spondyloarthritis. Materials and Methods In this prospective study, 47 consecutive participants (mean age, 27 years; age range, 14-41 years [28 male; mean age, 24 years; age range, 14-37 years] [19 female; mean age, 29 years; age range, 17-41 years]) underwent dual-energy CT and 3.0-T MRI between April 2016 and December 2017. Two independent readers visually evaluated all sacroiliac joints for the presence of abnormal marrow attenuation on dual-energy VNCa images using a four-point classification system (0, no edema; 1, mild edema; 2, moderate edema; 3, severe edema). CT numbers on VNCa images were determined with region-of-interest-based quantitative analysis. MRI was the reference standard for presence of bone marrow edema. Results Sensitivity, specificity, and accuracy of readers 1 and 2, respectively, in the identification of bone edema at CT were 87% and 93% (48 and 51 of 55), 94% and 91% (32 and 31 of 34), and 90% and 92% (80 and 82 of 89). Interobserver agreement was excellent (κ = 0.81). CT numbers from VNCa images increased from no edema to severe edema (P < .001). The area under the receiver operating characteristic curve was 0.93 for reader 1 and 0.91 for reader 2 in differentiation of the presence of bone marrow edema from no edema. A cutoff value of -33 HU derived from reader 1 yielded overall sensitivity, specificity, and accuracy of 90% (49 of 55), 83% (28 of 34), and 87% (77 of 89) in the detection of any extent of edema in the sacroiliac joints. Conclusion Dual-energy VNCa CT images had excellent diagnostic performance in evaluation of the extent of bone marrow edema in study participants with sacroiliitis associated with axial spondyloarthritis. © RSNA, 2018 See also the editorial by Guggenberger in this issue.

Diagnostic performance of dual-energy CT for the detection of bone marrow oedema: a systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review and meta-analysis was to assess the sensitivity and specificity of dual-energy CT (DECT) for the detection of bone marrow oedema (BME).

METHODS

An electronic search of the PubMed and EMBASE databases was conducted. Bivariate modelling and hierarchical summary receiver-operating characteristic modelling were performed to evaluate the overall diagnostic performance of DECT for BME. Subgroup analysis was performed according to the assessment type (qualitative vs. quantitative) and anatomical location (spine vs. appendicular skeleton). Meta-regression analyses were performed according to the subject, study, and DECT characteristics.

RESULTS

Twelve eligible studies (1901 lesions, 450 patients) were included. DECT exhibited a pooled sensitivity of 0.85 [95% confidence interval (CI): 0.78-0.90] and a pooled specificity of 0.97 (95% CI: 0.92-0.98) for BME detection. In addition, the diagnostic performance of qualitative assessment (sensitivity, 0.85; specificity, 0.97) was higher than that of quantitative assessment (sensitivity, 0.84; specificity, 0.88) of DECT findings. The diagnostic performance of DECT for the spine (sensitivity, 0.84; specificity, 0.98) and appendicular skeleton (sensitivity, 0.84; specificity, 0.93) were excellent. According to meta-regression analysis, the use of a tin filter, ≥ 2 image planes, and a slice thickness < 1 mm tended to exhibit higher sensitivity and hyperacute stage BME (< 24 h) tended to exhibit lower sensitivity.

CONCLUSIONS

These findings indicate that DECT has excellent sensitivity and specificity for BME detection. Qualitative assessment of DECT findings obtained using a tin filter, ≥ 2 image planes, and a 0.5-1-mm slice thickness in the acute stage BME (≥24 h) is recommended for more sensitive diagnosis.

KEY POINTS

• Overall, DECT is useful for the detection of BME (sensitivity, 85%; specificity-97%). • Qualitative assessment (sensitivity-85%; specificity-97%) is more accurate than quantitative assessment (sensitivity-84%; specificity-88%). • DECT showed excellent diagnostic performance for both the spine/appendicular skeleton (sensitivity-84%/84%; specificity-98%/93%).

The Role of Dual-Energy Computed Tomography in Musculoskeletal Imaging

Dual-energy computed tomography (DECT) enables material decomposition and virtual monochromatic images by acquiring 2 different energy X-ray data sets. DECT can detect musculoskeletal pathologic conditions that CT alone cannot, and that would otherwise require MR imaging. In this review, the authors discuss several useful techniques and applications of DECT in musculoskeletal research: virtual monochromatic images, virtual noncalcium images, gout, iodine map, and tendons.