Epigenetic adaptation drives monocyte differentiation into microglia-like cells upon engraftment into the retina.

The identification of specific markers for microglia has been a long-standing challenge. Recently, markers such as P2ry12, TMEM119, and Fcrls have been proposed as microglia-specific and widely used to explore microglial functions within various central nervous system (CNS) contexts. The specificity of these markers was based on the assumption that circulating monocytes retain their distinct signatures even after infiltrating the CNS. However, recent findings reveal that infiltrating monocytes can adopt microglia-like characteristics while maintaining a pro-inflammatory profile upon permanent engraftment in the CNS.In this study, we utilize bone marrow chimeras, single-cell RNA sequencing, ATAC-seq, flow cytometry, and immunohistochemistry to demonstrate that engrafted monocytes acquire expression of established microglia markers-P2ry12, TMEM119, Fcrls-and the pan-myeloid marker Iba1, which has been commonly mischaracterized as microglia-specific. These changes are accompanied by alterations in chromatin accessibility and shifts in chromatin binding motifs that are indicative of microglial identity. Moreover, we show that engrafted monocytes dynamically regulate the expression of CX3CR1, CCR2, Ly6C, and transcription factors PU.1, CTCF, RUNX, AP-1, CEBP, and IRF2, all of which are crucial for shaping microglial identity. This study is the first to illustrate that engrafted monocytes in the retina undergo both epigenetic and transcriptional changes, enabling them to express microglia-like signatures. These findings highlight the need for future research to account for these changes when assessing the roles of monocytes and microglia in CNS pathology.

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.

The Efficacy of a Named Entity Recognition AI Model for Identifying Incidental Pulmonary Nodules in CT Reports.

Purpose: This study evaluates the efficacy of a commercial medical Named Entity Recognition (NER) model combined with a post-processing protocol in identifying incidental pulmonary nodules from CT reports. Methods: We analyzed 9165 anonymized CT reports and classified them into 3 categories: no nodules, nodules present, and nodules >6 mm. For each report, a generic medical NER model annotated entities and their relations, which were then filtered through inclusion/exclusion criteria selected to identify pulmonary nodules. Ground truth was established by manual review. To better understand the relationship between model performance and nodule prevalence, a subset of the data was programmatically balanced to equalize the number of reports in each class category. Results: In the unbalanced subset of the data, the model achieved a sensitivity of 97%, specificity of 99%, and accuracy of 99% in detecting pulmonary nodules mentioned in the reports. For nodules >6 mm, sensitivity was 95%, specificity was 100%, and accuracy was 100%. In the balanced subset of the data, sensitivity was 99%, specificity 96%, and accuracy 97% for nodule detection; for larger nodules, sensitivity was 94%, specificity 99%, and accuracy 98%. Conclusions: The NER model demonstrated high sensitivity and specificity in detecting pulmonary nodules reported in CT scans, including those >6 mm which are potentially clinically significant. The results were consistent across both unbalanced and balanced datasets indicating that the model performance is independent of nodule prevalence. Implementing this technology in hospital systems could automate the identification of at-risk patients, ensuring timely follow-up and potentially reducing missed or late-stage cancer diagnoses.

Canadian radiology: 2024 update.

Radiology in Canada is advancing through innovations in clinical practices and research methodologies. Recent developments focus on refining evidence-based practice guidelines, exploring innovative imaging techniques and enhancing diagnostic processes through artificial intelligence. Within the global radiology community, Canadian institutions play an important role by engaging in international collaborations, such as with the American College of Radiology to refine implementation of the Ovarian-Adnexal Reporting and Data System for ultrasound and magnetic resonance imaging. Additionally, researchers have participated in multidisciplinary collaborations to evaluate the performance of artificial intelligence-driven diagnostic tools for chronic liver disease and pediatric brain tumors. Beyond clinical radiology, efforts extend to addressing gender disparities in the field, improving educational practices, and enhancing the environmental sustainability of radiology departments. These advancements highlight Canada's role in the global radiology community, showcasing a commitment to improving patient outcomes and advancing the field through research and innovation. This update underscores the importance of continued collaboration and innovation to address emerging challenges and further enhance the quality and efficacy of radiology practices worldwide.

Approach to Acute Traumatic and Nontraumatic Diaphragmatic Abnormalities.

Acute diaphragmatic abnormalities encompass a broad variety of relatively uncommon and underdiagnosed pathologic conditions, which can be subdivided into nontraumatic and traumatic entities. Nontraumatic abnormalities range from congenital hernia to spontaneous rupture, endometriosis-related disease, infection, paralysis, eventration, and thoracoabdominal fistula. Traumatic abnormalities comprise both blunt and penetrating injuries. Given the role of the diaphragm as the primary inspiratory muscle and the boundary dividing the thoracic and abdominal cavities, compromise to its integrity can yield devastating consequences. Yet, diagnosis can prove challenging, as symptoms may be vague and findings subtle. Imaging plays an essential role in investigation. Radiography is commonly used in emergency evaluation of a patient with a suspected thoracoabdominal process and may reveal evidence of diaphragmatic compromise, such as abdominal contents herniated into the thoracic cavity. CT is often superior, in particular when evaluating a trauma patient, as it allows rapid and more detailed evaluation and localization of pathologic conditions. Additional modalities including US, MRI, and scintigraphy may be required, depending on the clinical context. Developing a strong understanding of the acute pathologic conditions affecting the diaphragm and their characteristic imaging findings aids in efficient and accurate diagnosis. Additionally, understanding the appearance of diaphragmatic anatomy at imaging helps in differentiating acute pathologic conditions from normal variations. Ultimately, this knowledge guides management, which depends on the underlying cause, location, and severity of the abnormality, as well as patient factors. ©RSNA, 2024 Supplemental material is available for this article.

Utility of Dual-Energy Computed Tomography in Clinical Conundra.

Advancing medical technology revolutionizes our ability to diagnose various disease processes. Conventional Single-Energy Computed Tomography (SECT) has multiple inherent limitations for providing definite diagnoses in certain clinical contexts. Dual-Energy Computed Tomography (DECT) has been in use since 2006 and has constantly evolved providing various applications to assist radiologists in reaching certain diagnoses SECT is rather unable to identify. DECT may also complement the role of SECT by supporting radiologists to confidently make diagnoses in certain clinically challenging scenarios. In this review article, we briefly describe the principles of X-ray attenuation. We detail principles for DECT and describe multiple systems associated with this technology. We describe various DECT techniques and algorithms including virtual monoenergetic imaging (VMI), virtual non-contrast (VNC) imaging, Iodine quantification techniques including Iodine overlay map (IOM), and two- and three-material decomposition algorithms that can be utilized to demonstrate a multitude of pathologies. Lastly, we provide our readers commentary on examples pertaining to the practical implementation of DECT's diverse techniques in the Gastrointestinal, Genitourinary, Biliary, Musculoskeletal, and Neuroradiology systems.

Corrigendum to "Exploring the uncommon: Unusual instance of retained fractured needles in a patient of intravenous drugs abuse" [Radiology Case Reports 19 (2024) 1619-1623].

[This corrects the article DOI: 10.1016/j.radcr.2024.01.016.].

Frequently Encountered Artifacts in the Application of Dual-Energy Computed Tomography to Cardiovascular Imaging for Urate Crystals in Gout: A Matched-Control Study.

OBJECTIVE: There is surging interest in using dual-energy computed tomography (DECT) to identify cardiovascular monosodium urate (MSU) deposits in patients with gout. We sought to examine the prevalence and characterization of cardiovascular DECT artifacts using non-electrocardiogram (EKG)-gated DECT pulmonary angiograms. METHODS: We retrospectively reviewed non-EKG-gated DECT pulmonary angiograms performed on patients with and without gout at a single academic center. We noted the presence and locations of vascular green colorization using the default postprocessing two-material decomposition algorithm for MSU. The high- and low-energy grayscale images and advanced DECT measurements were used to determine whether they were true findings or artifacts. We classified artifacts into five categories: streak, contrast medium mixing, misregistration due to motion, foreign body, and noise. RESULTS: Our study included CT scans from 48 patients with gout and 48 age- and sex-matched controls. The majority of patients were male with a mean age of 67 years. Two independent observers attributed all areas of vascular green colorization to artifacts. The most common types of artifacts were streak (56% vs 57% between patients and controls, respectively) and contrast medium mixing (51% vs 65%, respectively). Whereas some of the default DECT measurements of cardiovascular green colorization were consistent with values reported for subcutaneous tophi, advanced DECT measurements were not consistent with that of tophi. CONCLUSION: Artifacts that could be misconstrued as cardiovascular MSU deposits were commonly identified in patients with and without gout on non-EKG-gated DECT pulmonary angiograms. These artifacts can inform future vascular DECT studies on patients with gout to minimize false-positive findings.

Exploring the uncommon: Unusual instance of retained fractured needles in a patient of intravenous drugs abuse.

Retained needle fragments commonly serve as sources of recurrent infections with a potential to embolize to the heart and lungs and can lead to life-threatening consequences. Here, we report a case of a 46-year-old male with a history of intravenous drug user and chronic forearm wounds, presenting with sepsis. Several retained needles are identified on CT scan, several days postadmission. This case highlights the importance of timely assessment of infectious sources in patients with history of intravenous drug abuse.

Establishing and Leading a 3D Postprocessing Radiology Lab: A Managerial and Leadership Perspective.

The rapid acquisition of larg volumes of thin-section CT images has created a considerable need and interest for 3D postprocessing during the interpretation of medical imaging. As a result of the increasing number of postprocessing applications, requiring diagnostic radiologists to perform postprocessing is no longer realistic. This article is a comprehensive review of medical resources regarding establishing a postprocessing radiology laboratory. Besides, leadership and managerial aspects have been covered through a professional business lens. In large-volume settings, a dedicated 3D postprocessing lab ensures the quality, reproducibility, and efficiency of images. Adequate staffing is necessary to fulfill the postprocessing requirements. Educational and experience requirements for 3D technologists may vary among different running laboratories. To evaluate the establishment and running of a 3D lab, it is beneficial to implement diagnostic radiology cost-effectiveness tools. Although establishing a 3D lab has many benefits, certain challenges should be considered. Outsourcing or offshoring may serve as alternatives for establishing a postprocessing laboratory. Building and operating a 3D lab is a significant change in healthcare facilities, and it is crucial for organizations to be aware of the strong resistance toward alternatives the status quo, known as the status quo trap. The change process has essential steps, and skipping the steps creates an illusion of speed but never produces satisfactory results. The organization should ensure the engagement of all interested parties in the whole process. Moreover, a clear vision and proper communication of the vision are vital, and it is crucial to value small wins and ensure expectation clarity in leading the lab during the process.

The Role of Dual-Energy CT in Solid Organ Injury.

The liver, spleen, and kidneys are the commonest injured solid organs in blunt and penetrating trauma. The American Association for the Surgery of Trauma (AAST) Organ Injury Scale (OIS) is the most widely accepted system for categorizing traumatic injuries. Grading systems allow clear communication of findings between clinical teams and assign a measurable severity of injury, which directly correlates with morbidity and mortality. The 2018 revised AAST OIS emphasizes reliance on CT for accurate grading; in particular regarding vascular injuries. Dual-Energy CT (DECT) has emerged as a promising tool with multiple clinical applications already demonstrated. In this review article, we summarize the basic principles of CT attenuation to refresh the minds of our readers and we scrutinize DECT's technology as opposed to conventional Single-Energy CT (SECT). This is followed by outlining the benefits of various DECT postprocessing techniques, which authors of this article refer to as the 3Ms (Mapping of Iodine, Material decomposition, and Monoenergetic virtual imaging), in aiding radiologists to confidently assign an OIS as well as problem solve complex injury patterns. In addition, a thorough discussion of changes to the revised AAST OIS focusing on definitions of key terms used in reporting injuries is described.

Underreported and underrecognized: a comprehensive imaging review of breast injury.

Breast injury is commonly encountered yet it remains significantly underreported. Injury to the breast may arise from either primary mechanisms or secondary or iatrogenic mechanisms. Primary mechanisms of breast injury include blunt force, seat-belt, penetrating, and thermal injury. Secondary or iatrogenic mechanisms of breast injury include breast biopsy or intervention as well as operative intervention and cardiopulmonary resuscitation. The severity of breast injury arising from these mechanisms is broad, ranging from breast contusion to avulsion. Sequelae of breast injury include fat necrosis and Mondor's disease. Radiologists play an integral role in the evaluation and management of breast injury both in the acute and non-acute settings. In the acute setting, radiologists must be able to recognize breast injury arising from primary mechanisms or iatrogenic or secondary mechanisms and to identify rare but potentially life-threatening complications promptly to ensure timely, appropriate management. In the non-acute setting, radiologists must be able to discern the sequalae of breast injury from other processes to prevent potentially unnecessary further evaluation and intervention. Nonetheless, though breast injury is commonly encountered there remain few guidelines and a lack of established recommendations for the evaluation and management of breast injury. We provide a comprehensive multi-modality imaging review of breast injury arising in the acute setting as well as the sequela of breast injury arising in the non-acute setting. Moreover, we provide an overview of the management of breast injury.

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.

Phase 2 Dose-Finding Study in Patients with Gout Using SEL-212, a Novel PEGylated Uricase (SEL-037) Combined with Tolerogenic Nanoparticles (SEL-110).

INTRODUCTION: SEL-212 is a developmental treatment for uncontrolled gout characterized by serum uric acid (sUA) levels ≥ 6 mg/dl despite treatment. It comprises a novel PEGylated uricase (SEL-037; also called pegadricase) co-administered with tolerogenic nanoparticles containing sirolimus (rapamycin) (SEL-110; also called ImmTOR®), which mitigates the formation of anti-drug antibodies (ADAs) against uricase and SEL-037 (PEGylated uricase), thereby enabling sustained sUA control (sUA < 6 mg/dl). The aim of this study was to identify appropriate dosing for SEL-037 and SEL-110 for use in phase 3 clinical trials. METHODS: This open-label phase 2 study was conducted in adults with symptomatic gout and sUA ≥ 6 mg/dl. Participants received five monthly infusions of SEL-037 (0.2 or 0.4 mg/kg) alone or in combination with three or five monthly infusions of SEL-110 (0.05-0.15 mg/kg). Safety, tolerability, sUA, ADAs, and tophi were monitored for 6 months. RESULTS: A total of 152 adults completed the study. SEL-037 alone resulted in rapid sUA reductions that were not sustained beyond 30 days in most participants due to ADA formation and loss of uricase activity. Levels of ADAs decreased with increasing doses of SEL-110 up to 0.1 mg/kg, with anti-uricase titers < 1080 correlating with sustained sUA control and reductions in tophi. Overall, 66% of evaluable participants achieved sUA control at week 20 following five monthly doses of SEL-037 0.2 mg/kg + SEL-110 0.1-0.15 mg/kg, whereas only 26% achieved sUA control at week 20 when SEL-110 was withdrawn after week 12. Compared to other dose combinations, SEL-037 0.2 mg/kg + SEL-110 0.15 mg/kg achieved the greatest sUA control at week 12 and was well-tolerated with no safety concerns. CONCLUSION: Results provide continued support for the use of multiple monthly administrations of SEL-037 0.2 mg/kg + SEL-110 0.1-0.15 mg/kg in clinical trials for SEL-212. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT02959918.

Gastropulmonary fistula following sleeve gastrectomy: use of dual-energy CT following oral contrast administration to confirm diagnosis.

Gastropulmonary fistula represents a late complication of sleeve gastrectomy and, if untreated, has high morbidity and mortality. We present a case report of a 29-year-old female who developed a gastropulmonary fistula 3 years after a sleeve gastrectomy. Dual energy CT of the chest and upper abdomen demonstrated a cavitary left lower lobe lesion associated with a focal complex pleural effusion; iodinated oral contrast confirmed the presence of a fistulous connection through the left hemidiaphragm. The patient underwent a thoracotomy, left lower lobectomy, resection of the infected segment of the left hemidiaphragm with primary repair, drainage of a subphrenic abscess and a gastric repair; the patient was discharged 2-weeks postprocedure.

Starting an Emergency Radiology Division: Scheduling and Staffing, Compensation, and Equity and Parity.

Establishing an emergency radiology division in a practice that has long-standing patterns of operational routines comes with both challenges and opportunities. In this article, considerations around scheduling and staffing, compensation, and equity and parity are provided with supporting literature references. Furthermore, a panel of experts having established, grown and managed emergency radiology divisions in North America and Europe share their experiences through a question and answer format.

Machine Learning Model for Chest Radiographs: Using Local Data to Enhance Performance.

PURPOSE: To develop and assess the performance of a machine learning model which screens chest radiographs for 14 labels, and to determine whether fine-tuning the model on local data improves its performance. Generalizability at different institutions has been an obstacle to machine learning model implementation. We hypothesized that the performance of a model trained on an open-source dataset will improve at our local institution after being fine-tuned on local data. METHODS: In this retrospective, institutional review board approved study, an ensemble of neural networks was trained on open-source datasets of chest radiographs for the detection of 14 labels. This model was then fine-tuned using 4510 local radiograph studies, using radiologists' reports as the gold standard to evaluate model performance. Both the open-source and fine-tuned models' accuracy were tested on 802 local radiographs. Receiver-operator characteristic curves were calculated, and statistical analysis was completed using DeLong's method and Wilcoxon signed-rank test. RESULTS: The fine-tuned model identified 12 of 14 pathology labels with area under the curves greater than .75. After fine-tuning with local data, the model performed statistically significantly better overall, and specifically in detecting six pathology labels (P < .01). CONCLUSIONS: A machine learning model able to accurately detect 14 labels simultaneously on chest radiographs was developed using open-source data, and its performance was improved after fine-tuning on local site data. This simple method of fine-tuning existing models on local data could improve the generalizability of existing models across different institutions to further improve their local performance.

Assessing tophaceous spinal gout treatment response using dual-energy CT as a point-of-care imaging modality: case report.

We describe a case of chronic tophaceous gout affecting the spine, hands, elbows, feet, and knees in a 67-year-old man with serum urate levels at 549 µmol/L whose response to treatment was successfully mapped using dual-energy computed tomography (DECT). The patient presented with exacerbation of acute-on-chronic lumbar back pain. He had received a diagnosis of gout 3 years prior to this presentation yet was not on any urate-lowering therapy. The patient received febuxostat 80 mg and colchicine 0.3 mg once daily and underwent DECT to assess baseline monosodium urate (MSU) burden. At baseline, MSU deposits were seen in the hands, elbows, feet, knees, and lumbar spine including the left L5-S1 facet joint encroaching onto the neural foramen. After 2.5 years of treatment, serum urate level was within the target range (< 360 µmol/L), and the patient underwent a follow-up DECT that revealed almost full resolution of MSU deposition in the spine, including the MSU-burdened facet joint and neural foramen in the lumbar spine, in addition to all the affected peripheral joints. This case is the first report of radiological evidence of nearly complete resolution of MSU deposits in spinal gout on DECT after urate-lowering therapy treatment, which demonstrates the utility of this imaging modality as a non-invasive investigational point-of-care imaging modality for mapping treatment response and identifying the etiology of back pain in a patient with chronic tophaceous spinal gout.

Dual Energy Computed Tomography Collagen Material Decomposition for Detection of Lumbar Spine Disc Extrusion and Sequestration: A Comparative Study With Greyscale Computed Tomography.

Purpose: To assess value of dual energy computed tomography (DECT) collagen material decomposition algorithm when combined with standard computed tomography (CT) in detection of lumbar disc extrusion and sequestration. Materials and Methods: Retrospective analysis of all patients with acute low back pain who had a diagnosis of lumbar spine disc extrusion and/or sequestration on Magnetic Resonance Imaging (MRI) (reference standard), and had undergone non-contrast DECT of the lumbar spine within 60 days of the MRI. Age and sex-matched control patients (n = 42) were included. Patients were grouped into standard, grey-scale CT only group and standard CT + DECT tendon images group. Two double-blinded radiologists reviewed both groups for presence of extrusion or sequestration. They also rated their diagnostic confidence on Likert 5-point scale. McNemar Chi-square test was used to compare diagnostic accuracy, unpaired t-test to compare reviewers diagnostic confidence, and Cohen's k (kappa) test for interobserver agreement. Results: The combined group showed higher overall sensitivity (96.6% vs 87.2%), specificity (99% vs 95.4%), and diagnostic accuracy (98.7% vs 94.5%) with a lower false positive rate (1.1% vs 4.6%). McNemar Chi-square test confirmed statistical significance (P = .03 and P = .02 for Reviewers R1 and R2, respectively). The mean diagnostic confidence was also significantly higher on combined group (R1: 3.74 ± 1.1 vs 3.47 ± 1.15 (P < .01) and R2: 3.91 ± 1.15 vs 3.72 ± 1.16 [mean ± SD] (P = .02)). Conclusion: Utilizing MRI as a reference standard, DECT tendon application combined with standard CT increases the sensitivity, specificity, and accuracy of detection of lumbar spine disc extrusion and sequestration, when compared to standard CT alone.