Relationship of Imaging-guided Corticosteroid Injections to COVID-19 Incidence in the Pandemic Recovery Period.

Background Corticosteroids injected for the treatment of musculoskeletal pain are systemically absorbed and can affect the immune response to viral infections. Purpose To determine the incidence of symptomatic COVID-19 disease in individuals receiving image-guided corticosteroid injections for musculoskeletal pain compared with the general population during the pandemic recovery period. Materials and Methods In this prospective cohort multicenter study, adults with a history of musculoskeletal pain who underwent imaging-guided intra-articular and spine corticosteroid injections from April 2020 to February 2021 were consecutively enrolled. Participants were followed for a minimum of 28 days through their electronic medical record (EMR) or by direct phone communication to screen for COVID-19 test results or symptoms. Clinical data, including body mass index (BMI), were also obtained from the EMR. The incidence of COVID-19 in the state was obtained using the Massachusetts COVID-19 Response Reporting website. The Student t test was used for continuous variable comparisons. Univariable analyses were performed using the Fisher exact test. Results A total of 2714 corticosteroid injections were performed in 2190 adult participants (mean age, 59 years ± 15 [SD]; 1031 women). Follow-up was available for 1960 participants (89%) who received 2484 injections. Follow-up occurred a mean of 97 days ± 33 (range, 28-141 days) after the injection. Of the 1960 participants, 10 had COVID-19 within 28 days from the injection (0.5% [95% CI: 0.24, 0.94]) and 43 had COVID-19 up to 4 months after the injection (2.2% [95% CI: 1.6, 2.9]). These incidence rates were lower than that of the population of Massachusetts during the same period (519 195 of 6 892 503 [7.5%], P < .001 for both 28 days and 4 months). Participants diagnosed with COVID-19 (n = 10) within 28 days from the injection had a higher BMI than the entire cohort (n = 1960) (mean, 32 kg/m2 ± 10 vs 28 kg/m2 ± 6; P = .04). Conclusion Adults who received image-guided corticosteroid injections for pain management during the pandemic recovery period had a lower incidence of symptomatic COVID-19 compared with the general population. © RSNA, 2022 Online supplemental material is available for this article.

Dual-Energy CT Images: Pearls and Pitfalls.

Dual-energy CT (DECT) is a tremendous innovation in CT technology that allows creation of numerous imaging datasets by enabling discrete acquisitions at more than one energy level. The wide range of images generated from a single DECT acquisition provides several benefits such as improved lesion detection and characterization, superior determination of material composition, reduction in the dose of iodine, and more robust quantification. Technological advances and the proliferation of various processing methods have led to the availability of diverse vendor-based DECT approaches, each with a different acquisition and image reconstruction process. The images generated from various DECT scanners differ from those from conventional single-energy CT because of differences in their acquisition techniques, material decomposition methods, image reconstruction algorithms, and postprocessing methods. DECT images such as virtual monochromatic images, material density images, and virtual unenhanced images have different imaging appearances, texture features, and quantitative capabilities. This heterogeneity creates challenges in their routine interpretation and has certain associated pitfalls. Some artifacts such as residual iodine on virtual unenhanced images and an appearance of pseudopneumatosis in a gas-distended bowel loop on material-density iodine images are specific to DECT, while others such as pseudoenhancement seen on virtual monochromatic images are also observed at single-energy CT. Recognizing the potential pitfalls associated with DECT is necessary for appropriate and accurate interpretation of the results of this increasingly important imaging tool. Online supplemental material is available for this article. ©RSNA, 2021.

Recognizing and Minimizing Artifacts at Dual-Energy CT.

Dual-energy CT (DECT) is an exciting innovation in CT technology with profound capabilities to improve diagnosis and add value to patient care. Significant advances in this technology over the past decade have improved our ability to successfully adopt DECT into the clinical routine. To enable effective use of DECT, one must be aware of the pitfalls and artifacts related to this technology. Understanding the underlying technical basis of artifacts and the strategies to mitigate them requires optimization of scan protocols and parameters. The ability of radiologists and technologists to anticipate their occurrence and provide recommendations for proper selection of patients, intravenous and oral contrast media, and scan acquisition parameters is key to obtaining good-quality DECT images. In addition, choosing appropriate reconstruction algorithms such as image kernel, postprocessing parameters, and appropriate display settings is critical for preventing quantitative and qualitative interpretive errors. Therefore, knowledge of the appearances of these artifacts is essential to prevent errors and allows maximization of the potential of DECT. In this review article, the authors aim to provide a comprehensive and practical overview of possible artifacts that may be encountered at DECT across all currently available commercial clinical platforms. They also provide a pictorial overview of the diagnostic pitfalls and outline strategies for mitigating or preventing the occurrence of artifacts, when possible. The broadening scope of DECT applications necessitates up-to-date familiarity with these technologies to realize their full diagnostic potential.

The effect of music on pain and subjective experience in image-guided musculoskeletal corticosteroid injections: a randomized controlled trial.

PURPOSE: To investigate the role of music on subjects undergoing routine image-guided musculoskeletal corticosteroid injections and its effect on post-procedure pain and subjective overall experience. MATERIALS AND METHODS: This prospective study was IRB-approved and HIPAA-compliant. A total of 126 subjects referred for outpatient image-guided musculoskeletal corticosteroid injections were enrolled in the study and randomized into a music offered group ((+)MO) and a no music offered group ((-)MO). (+)MO subjects were given the opportunity to listen to music during their corticosteroid injection. All subjects were then given an anonymous survey on which they recorded their pre-procedural and post-procedural pain on a scale from 0 to 9 and rated their overall experience and how likely they were to recommend our department for musculoskeletal procedures on scales from 1 to 5. RESULTS: (+)MO subjects had significantly lower post-procedural pain (p = 0.013) and significantly greater decrease in pain (p = 0.031) compared to (-)MO subjects. Among the (+)MO subjects, there was no statistically significant difference in post-procedure pain (p = 0.34) or change in pain (p = 0.62) if music was accepted or declined. However, subjects who listened to music did have lower post-procedural pain compared to those who did not listen to music (p = 0.012), although the differences in the decrease of pain between the two groups did not quite reach statistical significance (p = 0.062). CONCLUSIONS: Playing music during image-guided musculoskeletal corticosteroid injections may reduce patients' post-procedure pain. Offering patients some measure of control over their procedure may be a factor that contributes to decreased post-procedure pain as well.

Material Separation Using Dual-Energy CT: Current and Emerging Applications.

Dual-energy (DE) computed tomography (CT) offers the opportunity to generate material-specific images on the basis of the atomic number Z and the unique mass attenuation coefficient of a particular material at different x-ray energies. Material-specific images provide qualitative and quantitative information about tissue composition and contrast media distribution. The most significant contribution of DE CT-based material characterization comes from the capability to assess iodine distribution through the creation of an image that exclusively shows iodine. These iodine-specific images increase tissue contrast and amplify subtle differences in attenuation between normal and abnormal tissues, improving lesion detection and characterization in the abdomen. In addition, DE CT enables computational removal of iodine influence from a CT image, generating virtual noncontrast images. Several additional materials, including calcium, fat, and uric acid, can be separated, permitting imaging assessment of metabolic imbalances, elemental deficiencies, and abnormal deposition of materials within tissues. The ability to obtain material-specific images from a single, contrast-enhanced CT acquisition can complement the anatomic knowledge with functional information, and may be used to reduce the radiation dose by decreasing the number of phases in a multiphasic CT examination. DE CT also enables generation of energy-specific and virtual monochromatic images. Clinical applications of DE CT leverage both material-specific images and virtual monochromatic images to expand the current role of CT and overcome several limitations of single-energy CT. (©)RSNA, 2016.

Radiation dose and intra-articular access: comparison of the lateral mortise and anterior midline approaches to fluoroscopically guided tibiotalar joint injections.

PURPOSE: To compare the lateral mortise and anterior midline approaches to fluoroscopically guided tibiotalar joint injections with respect to successful intra-articular needle placement, fluoroscopy time, radiation dose, and dose area product (DAP). MATERIALS AND METHODS: This retrospective study was IRB-approved and HIPAA-compliant. 498 fluoroscopically guided tibiotalar joint injections were performed or supervised by one of nine staff radiologists from 11/1/2010-12/31/2013. The injection approach was determined by operator preference. Images were reviewed on a PACS workstation to determine the injection approach (lateral mortise versus anterior midline) and to confirm intra-articular needle placement. Fluoroscopy time (minutes), radiation dose (mGy), and DAP (µGy-m(2)) were recorded and compared using the student's t-test (fluoroscopy time) or the Wilcoxon rank sum test (radiation dose and DAP). RESULTS: There were 246 lateral mortise injections and 252 anterior midline injections. Two lateral mortise injections were excluded from further analysis because no contrast was administered. Intra-articular location of the needle tip was documented in 242/244 lateral mortise injections and 252/252 anterior midline injections. Mean fluoroscopy time was shorter for the lateral mortise group than the anterior midline group (0.7 ± 0.5 min versus 1.2 ± 0.8 min, P < 0.0001). Mean radiation dose and DAP were less for the lateral mortise group than the anterior midline group (2.1 ± 3.7 mGy versus 2.5 ± 3.5 mGy, P = 0.04; 11.5 ± 15.3 µGy-m(2) versus 13.5 ± 17.3 µGy-m(2), P = 0.006). CONCLUSION: Both injection approaches resulted in nearly 100% rates of intra-articular needle placement, but the lateral mortise approach used approximately 40% less fluoroscopy time and delivered 15% lower radiation dose and DAP to the patient.

Pelvic morphology in ischiofemoral impingement.

OBJECTIVE: To assess MRI measures to quantify pelvic morphology that may predispose to ischiofemoral impingement (IFI). We hypothesized that patients with IFI have a wider interischial distance and an increased femoral neck angle compared with normal controls. MATERIALS AND METHODS: The study was IRB-approved and complied with HIPAA guidelines. IFI was diagnosed based on clinical findings (hip or buttock pain) and ipsilateral edema of the quadratus femoris muscle on MRI. Control subjects did not report isolated hip/buttock pain and underwent MRI for surveillance of neoplasms or to exclude pelvic fractures. Two MSK radiologists measured the ischiofemoral (IF) and quadratus femoris (QF) distance, the ischial angle as a measure of inter-ischial distance, and the femoral neck angle. The quadratus femoris muscle was evaluated for edema. Groups were compared using ANOVA. Multivariate standard least-squares regression modeling was used to control for age and gender. RESULTS: The study group comprised 84 patients with IFI (53 ± 16 years, 73 female, 11 male) and 51 controls (52 ± 16 years, 33 female, 18 male). Thirteen out of 84 patients (15%) had bilateral IFI. Patients with IFI had decreased IF and QF distance (p < 0.0001), increased ischial angle (p = 0.004), and increased femoral neck angle (p = 0.02) compared with controls, independent of age and gender. CONCLUSION: Patients with IFI have increased ischial and femoral neck angles compared with controls. These anatomical variations in pelvic morphology may predispose to IFI. MRI is a useful method of not only assessing the osseous and soft-tissue abnormalities associated with IFI, but also of quantifying anatomical variations in pelvic morphology that can predispose to IFI.

Use of MR arthrography in detecting tears of the ligamentum teres with arthroscopic correlation.

OBJECTIVE: To demonstrate the normal appearance of the ligamentum teres on MR arthrography (MRA) and evaluate the accuracy of MRA in detecting ligamentum teres tears with arthroscopic correlation. MATERIALS AND METHODS: Institutional Review Board approval was obtained with a waiver for informed consent because of the retrospective study design. A total of 165 cases in 159 patients (111 females, 48 males; mean age 41 ± 12 years) who underwent both MRA and hip arthroscopy were evaluated for appearance of the ligamentum teres, including the size, number of bundles, and ligamentum teres tears. Marrow edema of the fovea capitis adjacent to the ligamentum teres insertion and the presence of hip plicae were also recorded. RESULTS: The mean thickness and length of the ligamentum teres were 3.5 ± 1.5 mm and 25.2 ± 3.8 mm, respectively. Sensitivity, specificity, positive and negative predictive value, and accuracy of MRA for the detection of ligamentum teres tears were 78, 97, 74, 97, and 95%, respectively. CONCLUSION: MRA is an accurate method to evaluate the normal morphology and to detect tears of the ligamentum teres.

MRI Findings in Patients Undergoing Triangular Fibrocartilage Complex Repairs Versus Patients Without Ulnar-Sided Wrist Pain.

Background: The clinical picture of ulnar-sided wrist pain is oftentimes confusing because various pathologies may be coexistent. In this study, we aimed: (1) to compare the prevalence of potential causes of ulnar-sided wrist pain on magnetic resonance imaging (MRI) in patients who underwent triangular fibrocartilage complex (TFCC) repair and control subjects: and (2) to evaluate whether inferior clinical results were associated with specific patient characteristics or other potential causes of ulnar-sided wrist pain. Methods: We included 67 patients who underwent a TFCC repair and 67 control subjects. The MRI scans were examined for sources of ulnar-sided wrist pain. After TFCC repair, 42 patients (63%) completed surveys, including Quick Disabilities of the Arm, Shoulder and Hand and pain scores. Bivariate analysis was performed to compare our groups and to identify factors associated with our outcomes. Results: We found significantly higher rates of distal radioulnar joint (DRUJ) arthritis (P = .033), extensor carpi ulnaris (ECU) pathology (P = .028), and ulnar styloid fractures (P = .028) in patients with TFCC repairs. With increasing age, increasing pathology in the pisotriquetral joint (P = .040), more ulnocarpal abutment (P = .0081), and more degenerative tears (P < .001) were seen in both groups. No demographic characteristics or MRI findings were significantly associated with our outcomes. Conclusions: We observed higher rates of DRUJ arthritis and ECU pathology in patients with TFCC tears undergoing repair compared with age- and sex-matched controls. This may be due to damage to the TFCC itself altering relationships of the DRUJ and the ECU subsheath, or it may reflect various pathologies that cause ulnar-sided wrist pain and drive patients toward surgery.

Carpometacarpal 4/5 Fracture Dislocations: Fracture Morphology and Surgical Treatment.

We conducted a retrospective review of six patients with carpometacarpal (CMC) ⅘ fracture-dislocations managed with ORIF by a single surgeon between October 2006 and August 2017. An open, dorsal approach to the hamate was used with a combination of interfragmentary screw fixation and Kirschner wire reduction in the CMC joints. At a mean of 96 days follow-up (range: 31-265), all patients had recovered wrist motion, excellent grip strength, and complete resolution of pain. There were no complications or reoperations during the postoperative period. Radiographic review showed restoration of anatomy and well-maintained congruity of the CMC joints. Our study has shown favorable outcomes after open reduction and internal fixation of the hamate body fracture with interfragmentary screws, when combined with stabilization of the CMC dislocation with percutaneous Kirschner wires. Fracture morphology does not appear to guide choice for specific hardware (size screw, headed/headless) or use of a washer. This is a level IV, therapeutic study.