Dual energy computed tomography evaluation of skeletal traumas

Occult femoral fracture: Be aware of dual energy computed tomography

A 74-year-old man was admitted to our emergency department following minor trauma. Plain radiographs and standard computed tomography (CT) scans revealed no signs of fractures. Subsequently, virtual noncalcium (VNCa) images were reconstructed, showing a linear area of bone marrow edema (BME) resembling a femoral neck fracture. Magnetic resonance imaging (MRI) was performed to confirm the presence of BME and an associated intraspongious fracture. In an emergency setting, dual-energy CT (DECT) and VNCa images can successfully identify occult femoral fractures, especially in patients with mild symptoms and minor trauma, thereby preventing misdiagnosis.

Potential of Dual-Energy CT-Based Collagen Maps for the Assessment of Disk Degeneration in the Lumbar Spine

RATIONALE AND OBJECTIVES

Lumbar disk degeneration is a common condition contributing significantly to back pain. The objective of the study was to evaluate the potential of dual-energy CT (DECT)-derived collagen maps for the assessment of lumbar disk degeneration.

PATIENTS AND METHODS

We conducted a retrospective analysis of 127 patients who underwent dual-source DECT and MRI of the lumbar spine between 07/2019 and 10/2022. The level of lumbar disk degeneration was categorized by three radiologists as follows: no/mild (Pfirrmann 1&2), moderate (Pfirrmann 3&4), and severe (Pfirrmann 5). Recall (sensitivity) and accuracy of DECT collagen maps were calculated. Intraclass correlation coefficient (ICC) was used to evaluate inter-reader reliability. Subjective evaluations were performed using 5-point Likert scales for diagnostic confidence and image quality.

RESULTS

We evaluated a total of 762 intervertebral disks from 127 patients (median age, 69.7 (range, 23.0-93.7), female, 56). MRI identified 230 non/mildly degenerated disks (30.2%), 484 moderately degenerated disks (63.5%), and 48 severely degenerated disks (6.3%). DECT collagen maps yielded an overall accuracy of 85.5% (1955/2286). Recall (sensitivity) was 79.3% (547/690) for the detection of no/mild lumbar disk degeneration, 88.7% (1288/1452) for the detection of moderate disk degeneration, and 83.3% (120/144) for the detection of severe disk degeneration (ICC=0.9). Subjective evaluations of DECT collagen maps showed high diagnostic confidence (median 4) and good image quality (median 4).

CONCLUSION

The use of DECT collagen maps to distinguish different stages of lumbar disk degeneration may have clinical significance in the early diagnosis of disk-related pathologies in patients with contraindications for MRI or in cases of unavailability of MRI.

Probing nanoscale structural response of collagen fibril in human Achilles tendon during loading using in situ SAXS

The specific viscoelastic mechanical properties of the human Achilles tendon are strongly dependent on the structural characteristics of collagen. Although research on the deformation mechanisms of the Achilles tendon in various animals is extensive, understanding of these mechanisms in the human Achilles tendon remains largely empirical and macroscopic. In this work, the evolution of D-space, orientation, and average length of voids between fibers are investigated during the stretching using SAXS techniques. Initially, the void length increases marginally, while the misorientation breadth decreased rapidly as the D-space steadily increased. In the second region, D-space and the void length increase sharply under rising stress, even though misorientation width decreased. During the third region, the increases in void length and D-space decelerate, but the misorientation width widens, suggesting the onset of irreversible microscopic fibril failure in the Achilles tendon. In the final region, the fibers undergo macroscopic failure, with D-space and void length returning to their initial states. The macroscopic alterations are elucidated by the nanoscale structural responses, providing a fundamental understanding of the mechanisms driving the complex biomechanics, tissue structural organization, and Achilles tendon regeneration.

Identification of Achille's Tendon Tears: Diagnostic Accuracy of Dual-Energy CT with Respect to MRI

Background: The aim was to assess the diagnostic accuracy of DECT in diagnosing Achilles tendon tears, using MRI as the reference for diagnosis. Methods: This feasibility study conducted prospectively at a single center included consecutive patients suffering from ankle pain who underwent DECT and MRI between April 2023 and October 2023. A total of three radiologists, blinded to the patient's clinical data, assessed the images. Achille Tendon injuries were diagnosed in case of thickened and inflamed tendons or in case of a partial or complete tear. Diagnostic accuracy values of DECT were calculated using a multi-reader approach. Inter-observer agreement was calculated using k statistics. Results: The final study population included 22 patients (mean age 48.5 years). At MRI, Achille's tendon lesion was present in 12 cases (54.5%) with 2 cases of complete rupture, 8 cases of partial tear (5 with tendon retraction), and 2 cases of tendon thickening. The mean thickness of injured tendons was 10 mm. At DECT, R1 was allowed to correctly classify 20/22 cases (90.9%), R2 19/22 cases (86.4%), and R3 18/22 cases (81.8%). At DECT, the mean thickness of the positively scored tendon was 10 mm for R1, 10.2 mm for R2, and 9.8 mm for R3. A very good agreement was achieved with regard to the evaluation of tears (k = 0.94), thickness (k = 0.96), and inflammatory changes (k = 0.82). Overall agreement was very good (k = 0.88). Conclusions: DECT showed a good diagnostic performance in identifying Achille's tendon tears, with respect to MRI.

Meta-analysis of the value of dual-energy computed tomography in the diagnosis of anterior cruciate ligament injuries of the knee

BACKGROUND

This meta-analysis assessed the efficacy of dual-energy computed tomography (DECT) in the diagnosis of anterior cruciate ligament (ACL) injuries.

METHODS

The literature search was performed up to December 8, 2023, and included a comprehensive examination of several databases: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang, and VIP. Diagnostic metrics sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and a summary receiver operating characteristic (SROC) were determined using a bivariate model analysis. Heterogeneity within the data was explored through subgroup analyses, which considered variables including geographical region, use of magnetic resonance imaging (MRI), arthroscopy, and study design.

RESULTS

The analysis included ten studies encompassing 544 patients. DECT demonstrated substantial diagnostic utility for ACL injuries of the knee, with a sensitivity of 0.91 (95% confidence interval [CI]: 0.88-0.94), a specificity of 0.90 (95% CI: 0.81-0.95), a PLR of 9.20 (95% CI: 4.50-19.00), a NLR of 0.10 (95% CI: 0.06-0.14), a DOR of 97.00 (95% CI: 35.00-268.00), and an area under the curve (AUC) of 0.95 (95% CI: 0.93-0.97). The subgroup analyses consistently showed high diagnostic precision for ACL injuries across Asian population (sensitivity: 0.91, specificity: 0.91, PLR: 9.90, NLR: 0.09, DOR: 105.00, AUC: 0.96), in MRI subgroup (sensitivity: 0.85, specificity: 0.94, PLR: 9.57, NLR: 0.18, DOR: 56.00, AUC: 0.93), in arthroscopy subgroup (sensitivity: 0.92, specificity: 0.89, PLR: 8.40, NLR: 0.09, DOR: 94.00, AUC: 0.95), for prospective studies (sensitivity: 0.92, specificity: 0.88, PLR: 7.40, NLR: 0.09, DOR: 78.00, AUC: 0.95), and for retrospective studies (sensitivity: 0.91, specificity: 0.93, AUC: 0.93).

CONCLUSION

DECT exhibits a high value in diagnosing ACL injuries. The significant diagnostic value of DECT provides clinicians with a powerful tool that enhances the accuracy and efficiency of diagnosis and optimizes patient management and treatment outcomes.

The utility of virtual monochromatic dual-energy computed tomography (DECT) in meniscal imaging: a technical evaluation

Purpose

To determine the feasibility of meniscal imaging using virtual monochromatic images obtained through dualenergy computed tomography (DECT) technique, and to determine which keV levels optimise contrast resolution.

Material and methods

All DECT exams were performed on a Discovery CT750 HD system from GE Healthcare. Virtual monochromatic images were reconstructed at 40 keV, 73 keV, 106 keV, and 139 keV. Contrast resolution of the medial and lateral menisci using a 5-point Likert scale at each keV level was determined through a consensus agreement by 2 fellowship-trained musculoskeletal radiologists. Friedman's and Wilcoxon signed rank tests were used to compare visualisation scores across different keV levels.

Results

Seventeen knee exams from 10 patients met criteria for inclusion in the study. All patients included in the study cohort were male. The median age of patients was 46 years (interquartile range, 35-53 years). Virtual monochromatic images at 40 keV demonstrated highest contrast resolution of the menisci, with a statistically significant difference between contrast resolution scores at 40 keV and 76 keV, Friedman test: p < 0.0001.

Conclusions

Meniscal imaging is feasible using DECT virtual monochromatic images at low keV levels. Improved contrast resolution at these specified KeV values could pave the way for further research in this field to determine its role in the future as an alternative option for assessment of the menisci in patients with contraindications to MRI or in the setting of a periarticular ferromagnetic foreign body obscuring the field of view.

A comparative study of image quality and diagnostic confidence in diagnosis and follow-up of scaphoid fractures using photon-counting detector CT and energy-integrating detector CT

PURPOSE

Scaphoid fractures in patients and assessment of healing using PCD-CT have, as far as we know, not yet been studied. Therefore, the aim was to compare photon counting detector CT (PCD-CT) with energy integrating detector CT (EID-CT) in terms of fracture visibility and evaluation of fracture healing.

METHOD

Eight patients with scaphoid fracture were examined with EID-CT and PCD-CT within the first week post-trauma, and with additional scans at 4, 6 and 8 weeks. Our clinical protocol for wrist examination with EID-CT was used (CTDIvol 3.1 ± 0.1 mGy, UHR kernel Ur77). For PCD-CT matched radiation dose, reconstruction kernel Br89. Quantitative analyses of noise, CNR, trabecular and cortical sharpness, and bone volume fraction were conducted. Five radiologists evaluated the images for fracture visibility, fracture gap consolidation and image quality, and rated their confidence in the diagnosis.

RESULTS

The trabecular and cortical sharpness were superior in images obtained with PCD-CT compared with EID-CT. A successive reduction in trabecular bone volume fraction during the immobilized periods was found with both systems. Despite higher noise and lower CNR with PCD-CT, radiologists rated the image quality of PCD-CT as superior. The visibility of the fracture line within 1-week post-trauma was rated higher with PCD-CT as was diagnostic confidence, but the subsequent assessments of fracture gap consolidation during healing process and the confidence in diagnosis were found equivalent between both systems.

CONCLUSION

PCD-CT offers superior visibility of bone microstructure compared with EID-CT. The evaluation of fracture healing and confidence in diagnosis were rated equally with both systems, but the radiologists found primary fracture visibility and overall image quality superior with PCD-CT.

Dual-energy CT: Impact of detecting bone marrow oedema in occult trauma in the Emergency

Dual-energy computed tomography (DECT) is an advanced imaging technique that acquires data using two distinct X-ray energy spectra, typically at 80 and 140 kVp, to differentiate materials based on their atomic number and electron density. This capability allows for the enhanced visualisation of various pathologies, including bone marrow oedema (BMO), by providing high-resolution images with notable energy spectral separation while maintaining radiation doses comparable to conventional CT. DECT's ability to create colour-coded virtual non-calcium (VNCa) images has proven particularly valuable in detecting traumatic bone marrow lesions (BMLs) and subtle fractures, offering a reliable alternative or complement to MRI. DECT has emerged as a significant tool in the detection and characterisation of bone marrow pathologies, especially in traumatic injuries. Its ability to generate high-resolution images and distinguish between different tissue types makes it a valuable asset in clinical diagnostics. With its comparable diagnostic accuracy to MRI and the added advantage of reduced examination time and increased availability, DECT represents a promising advancement in the imaging of BMO and related conditions.

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.

Musculoskeletal CT Imaging: State-of-the-Art Advancements and Future Directions

CT is one of the most widely used modalities for musculoskeletal imaging. Recent advancements in the field include the introduction of four-dimensional CT, which captures a CT image during motion; cone-beam CT, which uses flat-panel detectors to capture the lower extremities in weight-bearing mode; and dual-energy CT, which operates at two different x-ray potentials to improve the contrast resolution to facilitate the assessment of tissue material compositions such as tophaceous gout deposits and bone marrow edema. Most recently, photon-counting CT (PCCT) has been introduced. PCCT is a technique that uses photon-counting detectors to produce an image with higher spatial and contrast resolution than conventional multidetector CT systems. In addition, postprocessing techniques such as three-dimensional printing and cinematic rendering have used CT data to improve the generation of both physical and digital anatomic models. Last, advancements in the application of artificial intelligence to CT imaging have enabled the automatic evaluation of musculoskeletal pathologies. In this review, the authors discuss the current state of the above CT technologies, their respective advantages and disadvantages, and their projected future directions for various musculoskeletal applications.

Non-Operative Management of Polytraumatized Patients: Body Imaging beyond CT

In the transition from the operative to the conservative approach for the polytraumatized patients who undergo blunt trauma, diagnostic imaging has assumed a pivotal role, currently offering various opportunities, particularly in the follow-up of these patients. The choice of the most suitable imaging method in this setting mainly depends on the injury complications we are looking for, the patient conditions (mobilization, cooperation, medications, allergies and age), the biological invasiveness, and the availability of each imaging method. Computed Tomography (CT) represents the “standard” imaging technique in the polytraumatized patient due to the high diagnostic performance when a correct imaging protocol is adopted, despite suffering from invasiveness due to radiation dose and intravenous contrast agent administration. Ultrasound (US) is a readily available technology, cheap, bedside performable and integrable with intravenous contrast agent (Contrast enhanced US—CEUS) to enhance the diagnostic performance, but it may suffer particularly from limited panoramicity and operator dependance. Magnetic Resonance (MR), until now, has been adopted in specific contexts, such as biliopancreatic injuries, but in recent experiences, it showed a great potential in the follow-up of polytraumatized patients; however, its availability may be limited in some context, and there are specific contraindications, such as as claustrophobia and the presence non-MR compatible devices. In this article, the role of each imaging method in the body-imaging follow-up of adult polytraumatized patients will be reviewed, enhancing the value of integrated imaging, as shown in several cases from our experience.

Imaging of Structural Abnormalities of the Sacrum: The Old Faithful and Newly Emerging Techniques

The sacrum and sacroiliac joints pose a long-standing challenge for adequate imaging because of their complex anatomical form, oblique orientation, and posterior location in the pelvis, making them subject to superimposition. The sacrum and sacroiliac joints are composed of multiple diverse tissues, further complicating their imaging. Varying imaging techniques are suited to evaluate the sacrum, each with its specific clinical indications, benefits, and drawbacks. New techniques continue to be developed and validated, such as dual-energy computed tomography (CT) and new magnetic resonance imaging (MRI) sequences, for example susceptibility-weighted imaging. Ongoing development of artificial intelligence, such as algorithms allowing reconstruction of MRI-based synthetic CT images, promises even more clinical imaging options.

Virtual Non-contrast Imaging in The Abdomen and The Pelvis: An Overview

Virtual non-contrast (VNC) imaging is a post-processing technique generated from contrast-enhanced scans using dual-energy computed tomography (DECT). It is generated by removing iodine from imaging acquired at multiple energies. Myriad clinical studies have shown its ability to diagnose the various abdominal and pelvic pathologies discussed in the article. VNC is also a problem-solving tool for characterizing incidentally detected lesions ("incidentalomas"), often decreasing the need for additional follow-up imaging. It also obviates the multiphase image acquisitions to evaluate hematuria, hepatic steatosis, aortic endoleaks, and gastrointestinal bleeding by generating image datasets from different tissue attenuation values. The scope of this article is to provide an overview of various applications of VNC imaging obtained by DECT in the abdomen and pelvis.

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.

Anatomical analysis of inflammation in hand psoriatic arthritis by Dual-Energy CT Iodine Map

OBJECTIVE

This study aimed to identify the detailed location of inflammatory lesions and its frequency of hand PsA on DECT Iodine Map with referring the cadaveric specimen.

MATERIALS AND METHODS

Thirty-eight anatomical landmarks were selected as a potential inflammatory sites in the thumb and middle finger. We included 22 symptomatic PsA patients who underwent contrast enhanced DECT of the hand. MR images and macroscopic specimens of thumb and middle finger were prepared from a cadaver. Two musculoskeletal radiologists evaluated DECT with referring the cadaveric images to determine the precise location of inflammatory sites and its frequency.

RESULTS

The frequently observed inflammation sites of active PsA patients were either classical or functional entheses, and coincide with the well-known hypothesis that primary inflammatory sites of PsA are enthesis. We have noticed that there was remarkable enhancement around DIP joints (13.6 %-45.5 %).

CONCLUSION

DECT could assess the detailed anatomical sites of the inflammatory lesion in hand psoriatic arthritis, which coincided with enthesis.