Gender and Age Differences in the Associations Between Cortical Thickness and Hand Osteoarthritis Severity: Data from the Osteoarthritis Initiative.

OBJECTIVE: To evaluate gender differences in the association between metacarpal cortical thickness - a surrogate for bone density - and severity of radiographic hand osteoarthritis (HOA) in a longitudinal observational study. METHOD: Hand radiographs of 3,575 participants (2039 F/1536 M) from the Osteoarthritis Initiative were assessed at baseline and 48 months. A reader used a semi-automated software tool to calculate Tcort, a measurement of the cortical thickness, for metacarpals 2-4. Average Tcort at baseline and change in Tcort from baseline to 48 months was determined and stratified by gender and age for 7 5-year age groups. Spearman's rank correlation coefficients were calculated for the association of baseline Tcort and 2 measures of baseline HOA severity: the sum of Kellgren and Lawrence (KL) grade and total number of joints with radiographic HOA. Longitudinally, logistic regression was used to assess the relationship of Tcort loss to new finger joint radiographic HOA, increase in KL grades, and incident hand pain. RESULTS: Male Tcort was higher than females. Significant correlations between Tcort and radiographic severity were noted for women but not men, with stronger associations among women >60 years (rho=-0.25; 95% CI= -0.31- -0.19). Statistically significant associations were seen between Tcort change and radiographic osteoarthritis change among women but not men, with substantial gender differences for Tcort change, particularly ages 50 to 70 years (p<0.01; e.g.Tcort change ages 55 to <60: Males=-0.182(0.118), Females=-0.219(0.124). CONCLUSION: We found significant HOA-related gender differences in cortical thickness, suggesting the involvement of female bone loss during and after menopause.

Chronic Nonspinal Osteomyelitis in Adults: Consensus Recommendations on Percutaneous Bone Biopsies from the Society of Academic Bone Radiologists.

The diagnosis and management of chronic nonspinal osteomyelitis can be challenging, and guidelines regarding the appropriateness of performing percutaneous image-guided biopsies to acquire bone samples for microbiological analysis remain limited. An expert panel convened by the Society of Academic Bone Radiologists developed and endorsed consensus statements on the various indications for percutaneous image-guided biopsies to standardize care and eliminate inconsistencies across institutions. The issued statements pertain to several commonly encountered clinical presentations of chronic osteomyelitis and were supported by a literature review. For most patients, MRI can help guide management and effectively rule out osteomyelitis when performed soon after presentation. Additionally, in the appropriate clinical setting, open wounds such as sinus tracts and ulcers, as well as joint fluid aspirates, can be used for microbiological culture to determine the causative microorganism. If MRI findings are positive, surgery is not needed, and alternative sites for microbiological culture are not available, then percutaneous image-guided biopsies can be performed. The expert panel recommends that antibiotics be avoided or discontinued for an optimal period of 2 weeks prior to a biopsy whenever possible. Patients with extensive necrotic decubitus ulcers or other surgical emergencies should not undergo percutaneous image-guided biopsies but rather should be admitted for surgical debridement and intraoperative cultures. Multidisciplinary discussion and approach are crucial to ensure optimal diagnosis and care of patients diagnosed with chronic osteomyelitis.

Associations of inflammatory and metabolic biomarkers with incident erosive hand osteoarthritis in the osteoarthritis initiative cohort.

OBJECTIVE: Erosive hand osteoarthritis (eHOA) is a subtype of hand osteoarthritis (OA) that develops in finger joints with pre-existing OA and is differentiated by clinical characteristics (hand pain/disability, inflammation, and erosions) that suggest inflammatory or metabolic processes. METHOD: This was a longitudinal nested case-cohort design among Osteoarthritis Initiative participants who had hand radiographs at baseline and 48-months, and biospecimens collected at baseline. We classified incident radiographic eHOA in individuals with ≥1 joint with Kellgren-Lawrence ≥2 and a central erosion present at 48-months but not at baseline. We used a random representative sample (n = 1282) for comparison. We measured serum biomarkers of inflammation, insulin resistance and dysglycemia, and adipokines using immunoassays and enzymatic colorimetric procedures, blinded to case status. RESULTS: Eighty-six participants developed incident radiographic eHOA. In the multivariate analyses adjusted for age, gender, race, smoking, and body mass index, and after adjustment for multiple analyses, incident radiographic eHOA was associated with elevated levels of interleukin-7 (risk ratio (RR) per SD = 1.30 [95% confidence interval (CI) 1.09, 1.55] p trend 0.01). CONCLUSION: This exploratory study suggests an association of elevated interleukin-7, an inflammatory cytokine, with incident eHOA, while other cytokines or biomarkers of metabolic inflammation were not associated. Interleukin-7 may mediate inflammation and tissue damage in susceptible osteoarthritic finger joints and participate in erosive progression.

Subchondral Insufficiency Fractures of the Knee: A Clinical Narrative Review.

¼ Subchondral insufficiency fractures of the knee (SIFKs) are subchondral plate fractures with a prevalence of 2% to 4% of all knee injuries.¼ Magnetic resonance imaging is the gold standard for evaluating SIFK, while plain radiographs have limited the use in the diagnosis of SIFK.¼ Among patients with SIFK, 50% to 100% have meniscal pathology.¼ Medical therapies and standard treatments traditionally used in the management of knee osteoarthritis differ from recommended management of SIFK patients.¼ Randomized controlled trials and cohort studies with long-term follow-up are needed to determine the optimal rehabilitation protocol, interventional therapy, and prognosis of SIFK patients.

Increased Effusion Synovitis for Those With a Dysregulated Inflammatory Response After an Anterior Cruciate Ligament Injury.

Introduction The progression to posttraumatic osteoarthritis (PTOA) after an anterior cruciate ligament (ACL) injury is likely multifactorial, involving biological, mechanical, and psychosocial factors. Following acute joint trauma, there appears to be a subset of patients that demonstrate a dysregulated inflammatory response. This pro-inflammatory phenotype, or "Inflamma-type," is characterized by an amplified pro-inflammatory response combined with a lack of attendant anti-inflammatory response and has been observed following both an ACL injury and an intra-articular fracture. The aims of this study were to: 1) compare magnetic resonance imaging (MRI)-measured effusion synovitis between those with vs. without a dysregulated inflammatory response, and 2) assess the correlations between effusion synovitis and synovial fluid concentrations of proinflammatory cytokines, degradative enzymes, and synovial fluid biomarkers of cartilage degradation. Methods A cluster analysis was previously performed with synovial fluid concentrations of biomarkers of inflammation and cartilage degradation from 35 patients with acute ACL injuries. Patients were then categorized into two groups: a pro-inflammatory phenotype ("Inflamma-type") and those with a more normal inflammatory response to injury (NORM). Effusion synovitis measured from each patient's preoperative clinical MRI scan was compared between the Inflamma-type and NORM groups using an independent, two-tailed t-test. In addition, Spearman's rho non-parametric correlations were calculated to evaluate the relationship between effusion synovitis and each of the synovial fluid concentrations of pro-inflammatory cytokines, degradative enzymes, and biomarkers of cartilage degradation and bony remodeling. Results Effusion synovitis was significantly greater for the Inflamma-type (10.9±3.8 mm) than the NORM group (7.4±4.4 mm, p=0.04, Cohen's d=0.82). Effusion synovitis significantly correlated with matrix metalloproteinase-3 (rho=0.63, p<0.001), matrix metalloproteinase-1 (rho=0.50, p=0.003), and sulfated glycosaminoglycan (rho=0.42, p=0.01). No other significant correlations were present. Conclusion Effusion synovitis was significantly greater for those that demonstrated a dysregulated inflammatory response after acute ACL injury than those with a more normal response to injury. Effusion synovitis was also found to significantly correlate with synovial fluid concentrations of degradative enzymes and a biomarker of early cartilage degradation. Future work is needed to determine if non-invasive methods, such as MRI or ultrasound, may accurately identify patients within this pro-inflammatory phenotype and whether this subset is more prone to more rapid PTOA changes after injury.

Quantitative bone marrow lesion, meniscus, and synovitis measurement: current status.

Imaging plays a pivotal role in osteoarthritis research, particularly in epidemiological and clinical trials of knee osteoarthritis (KOA), with the ultimate goal being the development of an effective drug treatment for future prevention or cessation of disease. Imaging assessment methods can be semi-quantitative, quantitative, or a combination, with quantitative methods usually relying on software to assist. The software generally attempts image segmentation (outlining of relevant structures). New techniques using artificial intelligence (AI) or deep learning (DL) are currently a frequent topic of research. This review article provides an overview of the literature to date, focusing primarily on the current status of quantitative software-based assessment techniques of KOA using magnetic resonance (MR) imaging. We will concentrate on the imaging evaluation of three specific structural imaging biomarkers: bone marrow lesions (BMLs), meniscus, and synovitis consisting of effusion synovitis (ES) and Hoffa's synovitis (HS). A brief clinical and imaging background review of osteoarthritis evaluation, particularly relating to these three structural markers, is provided as well as a general summary of the software methods. A summary of the literature with respect to each KOA assessment method will be presented overall as well as with respect to each specific biomarker individually. Novel techniques, as well as future goals and directions using quantitative imaging assessment, will be discussed.

Imaging Features of Calcium Pyrophosphate Deposition Disease: Consensus Definitions From an International Multidisciplinary Working Group.

OBJECTIVE: To develop definitions for imaging features being considered as potential classification criteria for calcium pyrophosphate deposition (CPPD) disease, additional to clinical and laboratory criteria, and to compile example images of CPPD on different imaging modalities. METHODS: The American College of Rheumatology and European Alliance of Associations for Rheumatology CPPD classification criteria Imaging Advisory Group (IAG) and Steering Committee drafted definitions of imaging features that are characteristic of CPPD on conventional radiography (CR), conventional computed tomography (CT), dual-energy CT (DECT), and magnetic resonance imaging (MRI). An anonymous expert survey was undertaken by a 35-member Combined Expert Committee, including all IAG members. The IAG and 5 external musculoskeletal radiologists with expertise in CPPD convened virtually to further refine item definitions and voted on example images illustrating CR, CT, and DECT item definitions, with ≥90% agreement required to deem them acceptable. RESULTS: The Combined Expert Committee survey indicated consensus on all CR definitions. The IAG and external radiologists reached consensus on CT and DECT item definitions, which specify that calcium pyrophosphate deposits appear less dense than cortical bone. The group developed an MRI definition and acknowledged limitations of this modality for CPPD. Ten example images for CPPD were voted acceptable (4 CR, 4 CT, and 2 DECT), and 3 images of basic calcium phosphate deposition were voted acceptable to serve as contrast against imaging features of CPPD. CONCLUSION: An international group of rheumatologists and musculoskeletal radiologists defined imaging features characteristic of CPPD on CR, CT, and DECT and assembled a set of example images as a reference for future clinical research studies.

Racket or Bat Sports: No Association With Thumb-Base Osteoarthritis.

CONTEXT: Repetitive joint use is a risk factor for osteoarthritis, which is a leading cause of disability. Sports requiring a racket or bat to perform repetitive high-velocity impacts may increase the risk of thumb-base osteoarthritis. However, this hypothesis remains untested. OBJECTIVE: To determine if a history of participation in racket or bat sports was associated with the prevalence of thumb-base osteoarthritis. DESIGN: Descriptive epidemiologic study. SETTING: Four US clinical sites associated with the Osteoarthritis Initiative. PATIENTS OR OTHER PARTICIPANTS: We recruited 2309 men and women from the community. Eligible participants had dominant-hand radiographic readings, hand symptom assessments, and historical physical activity survey data. MAIN OUTCOME MEASURE(S): A history of exposure to racket or bat sports (badminton, baseball or softball, racketball or squash, table tennis [or ping pong], tennis [doubles], or tennis [singles]) was based on self-reported recall data covering 3 age ranges (12-18, 19-34, and 35-49 years). Prevalent radiographic thumb-base osteoarthritis was defined as Kellgren-Lawrence grade >2 in the first carpometacarpal joint or scaphotrapezoidal joint at the Osteoarthritis Initiative baseline visit. Symptomatic thumb-base osteoarthritis was defined as radiographic osteoarthritis and hand or finger symptoms. RESULTS: Radiographic or symptomatic thumb-base osteoarthritis was present in 355 (34%) and 56 (5%), respectively, of men (total = 1049) and 535 (42%) and 170 (13%), respectively, of women (total = 1260). After adjusting for age, race, and education level, we found no significant associations between a history of any racket or bat sport participation and thumb-base osteoarthritis (radiographic or symptomatic; odds ratios ranged from 0.82 to 1.34). CONCLUSIONS: In a community-based cohort, a self-reported history of participation in racket or bat sports was not associated with increased odds of having radiographic or symptomatic thumb-base osteoarthritis in the dominant hand.

Peroneal Sheath Volumes Are Greater in Patients With Peroneal Pathology Compared With Controls.

BACKGROUND: Peroneal tendon pathology is common. Several factors have been implicated, including low-lying muscles and accessory tendons. Studies have reported on the presence and length measurements of these structures. This study evaluates volume measurements within the sheath using magnetic resonance images for patients with operatively treated peroneal tendon pathology and control patients without peroneal disease. METHODS: Fifty-one patients with peroneal tendon pathology and 15 controls were included. The volumes of the peroneal sheath, peroneal tendons, peroneal muscle, and accessory peroneus tendons were measured. The distal extent of the peroneus brevis (PB) muscle was measured. Volume and length measurements were then compared. RESULTS: The mean PB muscle length from the tip of the fibula was 5.55 ± 2.5 mm (peroneal group) and 11.79 ± 4.07 mm (control) (P = .017). The mean peroneal sheath volume was 7.06 versus 5.12 mL, respectively (P = .001). The major contributors to this increased volume was the tenosynovitis (3.58 vs 2.56 mL, respectively; P = .019), the peroneal tendons (2.17 vs 1.7 mL, P = .004), and the accessory peroneus tendon + PB muscle (1.31 vs 0.86 mL, P = .023). CONCLUSION: The current study supports that the PB muscle belly is more distal in patients with peroneal tendon pathology. The study also demonstrates increased total volume within the peroneal sheath among the same patients. We propose that increased volume within the sheath, regardless of what structure is enlarged, is associated with peroneal tendon pathology. Further studies are needed to determine if debridement and decompression of the sheath will result in improved functional outcomes for these patients. LEVELS OF EVIDENCE: Level III: Case control imaging study.

Association of markers of patellofemoral maltracking to cartilage damage and bone marrow lesions on MRI: Data from the 2016 Olympic Games of Rio De Janeiro.

BACKGROUND: Patellofemoral joint (PFJ) disease is a common ailment in elite athletes. Our aim is to report the frequency of superolateral Hoffa's fat pad (SHFP) edema, and PFJ cartilage damage and bone marrow lesions (BML), among Olympian athletes, and to study the association between measurements of trochlear morphology and vertical patellar position and a) PFJ cartilage damage or BML, and b) SHFP edema. METHODS: All knee MRI, performed in the Olympic Village and polyclinics, of participating athletes in the 2016 Olympic Games of Rio de Janeiro were included. MRI were scored for PFJ cartilage damage and BML, and SHFP edema. Trochlear morphology measurements included sulcus angle, trochlear angle, lateral trochlear inclination, and medial trochlear inclination. Insall-Salvati ratio was also assessed. RESULTS: One hundred twenty-one knee MRIs were included (62 female, 51.2 %). The highest frequencies of PFJ cartilage damage, combination of PFJ cartilage damage and BML, and SHFP edema were found among Beach Volleyball and Volleyball athletes. SHFP edema was more common among female compared to male Olympian athletes. We found no statistically significant associations between different measurements of trochlear morphology/vertical patellar position, and 1. SHFP edema, and 2. PFJ cartilage damage/BML. CONCLUSION: SHFP edema and the combination of PFJ cartilage damage and BML are highly frequent among Olympic athletes especially those competing in Beach volleyball and Volleyball. SHFP edema is more common among female athletes. Further studies are needed to determine whether PFJ cartilage damage has a stronger association to sports disciplines rather than trochlear morphology.

Whole-body Computed Tomography Versus Dual Energy X­ray Absorptiometry for Assessing Heterotopic Ossification in Fibrodysplasia Ossificans Progressiva.

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare genetic disorder that leads to heterotopic ossification (HO), resulting in progressive restriction of physical function. In this study, low-dose, whole-body computed tomography (WBCT) and dual energy X-ray absorptiometry (DXA) were evaluated to determine the preferred method for assessing total body burden of HO in patients with FOP. This was a non-interventional, two-part natural history study in patients with FOP (NCT02322255; date of registration: December 2014). In Part A (described here), WBCT and DXA scans were individually assessed for HO presence and severity across 15 anatomical regions. All images were independently reviewed by an expert imaging panel. Ten adult patients were enrolled across four sites. The sensitivity to HO presence and severity varied considerably between the two imaging modalities, with WBCT demonstrating HO in more body regions than DXA (76/138 [55%] versus 47/113 [42%]) evaluable regions). Inability to evaluate HO presence, due to overlapping body regions (positional ambiguity), occurred less frequently by WBCT than by DXA (mean number of non-evaluable regions per scan 1.2 [standard deviation: 1.5] versus 2.4 [1.4]). Based on the increased sensitivity and decreased positional ambiguity of low-dose WBCT versus DXA in measuring HO in patients with FOP, low-dose WBCT was chosen as the preferred imaging for measuring HO. Therefore, low-dose WBCT was carried forward to Part B of the natural history study, which evaluated disease progression over 36 months in a larger population of patients with FOP.

Snapping Plantaris Tendon: A Rare Case in a Competitive Dancer.

Pathology associated with the plantaris includes rupture of the tendon and an association with mid-substance Achilles tendinopathy in some patients. There have only been two previous case reports in the literature in English language describing snapping of the plantaris tendon. We present a case report of a 15-year-old female competitive dancer who described pain and an audible popping at the medial margin of the Achilles tendon while squatting. Physical examination revealed visible and audible popping of the plantaris, and ultrasonography confirmed the diagnosis. After symptoms persisted despite nonsurgical treatment with physical therapy, the patient underwent an open plantaris tenotomy. By 8 weeks after surgery, she had resumed dancing. Twenty-three months after her operation, she reported an excellent outcome and full recovery with no limitations to her physical activity. She reported having no pain, a Foot and Ankle Ability Measure Activities of Daily Living Subscale score of 100, and a Foot and Ankle Ability Measure Sports Subscale score of 100. This case demonstrates a successful course of treatment for this uncommon pathology within the context of a competitive dancer.

Erosive Hand Osteoarthritis: Incidence and Predictive Characteristics Among Participants in the Osteoarthritis Initiative.

OBJECTIVE: To evaluate age, sex, race, osteoarthritis (OA) severity, metabolic factors, and bone health as risk factors for erosive hand OA at baseline and its incidence over a 48-month period. METHODS: This was a longitudinal cohort study that included participants from the Osteoarthritis Initiative (OAI) with complete hand radiographs from baseline and 48-month visits who were eligible at baseline for incident erosive hand OA (i.e., had or were at risk for knee OA [criterion for OAI inclusion] and did not currently have erosive hand OA). Individuals were classified as having erosive hand OA if the Kellgren/Lawrence (K/L) grade was ≥2 in at least 1 interphalangeal joint on 2 different fingers and central erosion was present in at least 1 joint. RESULTS: Of the 3,365 individuals without prevalent erosive hand OA at baseline, 86 (2.6%) developed erosive hand OA during the 48-month period. Risk factors included older age (relative risk [RR] per SD 1.63 [95% confidence interval 1.35-1.97]), female sex (RR 2.47 [95% confidence interval 1.52-4.02]), greater OA severity (sum K/L grade 13.9 versus 5.3; P < 0.001), and less cortical width (1.38 mm versus 1.52 mm; P < 0.001). After 48 months, subjects who had developed erosive hand OA were characterized by greater progression of radiographic OA (i.e., joint space narrowing, K/L grade progression [RR 1.35], and loss of cortical thickness [RR 1.23]), adjusted for age, sex, race, body mass index, and baseline OA severity (sum K/L grade). CONCLUSION: These findings demonstrate that erosive hand OA is more common in older women and is strongly associated with severity of articular structural damage and its progression. Individuals who develop erosive hand OA have thinner bones prior to erosive hand OA development and as it progresses, suggesting that erosive hand OA is a disorder of skeletal frailty.

Association of quantitative measures of effusion-synovitis and hoffa-synovitis with radiographic and pain progression: Data from the FNIH OA biomarkers consortium.

Objective: To validate a semi-automated software method of quantifying knee osteoarthritis (KOA) related effusion-synovitis (ES) and Hoffa-synovitis (HS) on MRI. Materials and methods: 301 subjects were randomly selected from the FNIH sub cohort, a nested case control study within the Osteoarthritis Initiative (OAI), and distributed into 4 groups based on pain and radiographic progression. Measurements of ES and HS volume were made by 2 readers. Criterion validation was assessed through comparison with the MRI Osteoarthritis Knee Score (MOAKS) and the Spearman correlation coefficient r value. Reader reliability was measured on a subset of 30 subjects and intra-class correlation coefficients (ICCs). Clinical validity was assessed based on case control status using logistic regression and the area under the curve (AUC). Results: ES volume was highly correlated with MOAKS Scores (r â€‹= â€‹0.74), as was the HS measure but to a lesser extent (r â€‹= â€‹0.55). For ES, the intra-reader and intra-reader precision ICCs were 0.83 and 0.95 respectively and 0.98 and 0.96 for HS. For clinical validity, we found similar AUC values when comparing the software method to MOAKS. The average reader time was less than 15 â€‹min per knee for both ES and HS. Conclusion: We have demonstrated the validity of an efficient, accurate, and rapid ES and HS measurement method for KOA using MRI. To our knowledge, this is the first such software to measure both ES and HS. This method will offer an objective and efficient tool for clinical trials and other epidemiologic studies of KOA.

Do non-weight-bearing knee radiographs for chronic knee pain result in increased follow-up imaging?

OBJECTIVE: While weight-bearing radiographs are considered the optimal method for evaluation of joint spaces in osteoarthritis, non-weight-bearing radiographs are often performed. The purpose of this study is to evaluate the rate of follow-up radiographs in patients receiving non-weight-bearing radiographs for chronic knee pain in the outpatient setting, compared with patients receiving weight-bearing radiographs. MATERIALS AND METHODS: Consecutive patients who received non-weight-bearing knee radiographs for chronic knee pain between January 1, 2018, and June 15, 2019, were included. Exclusion criteria included trauma, concern for infection or tumor, and post-surgical radiographs. An age- and sex-matched control group of 100 patients who received weight-bearing knee radiographs was compiled. The proportion of follow-up radiographs within 1 year was compared between the study and control groups with chi-squared tests. RESULTS: Four hundred non-weight-bearing knee radiographic examinations were included. There were 74/400 (18.5%) follow-up radiographs within 12 months. All follow-up radiographs were weight-bearing. In the control group, 4/100 (4%) had follow-up weight-bearing radiographs within 1 year (p < 0.001). CONCLUSION: Outpatients who underwent non-weight-bearing knee radiographs for chronic pain had a higher frequency of repeat imaging than those who initially underwent weight-bearing knee radiographs. These results suggest that non-weight-bearing knee radiographs are of lower clinical utility compared with weight-bearing radiographs.

ACR Appropriateness Criteria® Acute Trauma to the Ankle.

Acute injuries to the ankle are frequently encountered in the setting of the emergency room, sport, and general practice. This ACR Appropriateness Criteria defines best practices for imaging evaluation for several variants of patients presenting with acute ankle trauma. The variants include scenarios when Ottawa Rules can be evaluated, when there are exclusionary criteria, when Ottawa Rules cannot be evaluated, as well as specific injuries. Clinical scenarios are followed by the imaging choices and their appropriateness with an accompanying narrative explanation to help physicians to order the most appropriate imaging test. 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.

Use of Advanced Imaging for Radiographically Occult Hip Fracture in Elderly Patients: A Systematic Review and Meta-Analysis.

Background The overall rate of hip fractures not identified on radiographs but that require surgery (ie, surgical hip fractures) remains unclear in elderly patients who are suspected to have such fractures based on clinical findings. Moreover, the importance of advanced imaging in these patients has not been comprehensively assessed. Purpose To estimate the frequency of radiographically occult hip fracture in elderly patients, to define the higher-risk subpopulation, and to determine the diagnostic performance of CT and bone scanning in the detection of occult fractures by using MRI as the reference standard. Materials and Methods A literature search was performed to identify English-language observational studies published from inception to September 27, 2018. Studies were included if patients were clinically suspected to have hip fracture but there was no radiographic evidence of surgical hip fracture (including absence of any definite fracture or only presence of isolated greater trochanter [GT] fracture). The rate of surgical hip fracture was reported in each study in which MRI was used as the reference standard. The pooled rate of occult fracture, diagnostic performance of CT and bone scanning, and strength of evidence (SOE) were assessed. Results Thirty-five studies were identified (2992 patients; mean age, 76.8 years ± 6.0 [standard deviation]; 66% female). The frequency of radiographically occult surgical hip fracture was 39% (1110 of 2835 patients; 95% confidence interval [CI]: 35%, 43%) in studies of patients with no definite radiographic fracture and 92% (134 of 157 patients; 95% CI: 83%, 98%) in studies of patients with radiographic evidence of isolated GT fracture (moderate SOE). The frequency of occult fracture was higher in patients aged at least 80 years (44%, 529 of 1184), those with an equivocal radiographic report (58%, 71 of 126), and those with a history of trauma (41%, 977 of 2370) (moderate SOE). CT and bone scanning yielded comparable diagnostic performance in the detection of radiographically occult hip fracture (P = .67), with a sensitivity of 79% and 87%, respectively (low SOE). Conclusion Elderly patients with acute hip pain and negative or equivocal findings at initial radiography have a high frequency of occult hip fractures. Therefore, the performance of advanced imaging (preferably MRI) may be clinically appropriate in all such patients. © RSNA, 2020 Online supplemental material is available for this article.

ACR Appropriateness Criteria® Acute Trauma to the Knee.

Acute trauma to the knee is a common presentation seen in the emergency department. After a routine clinical examination, imaging is frequently performed to facilitate the diagnosis and almost always starts with radiographs. If clinically indicated, advanced cross-sectional imaging may then be performed for further evaluation. CT is often performed for preoperative planning of the complex tibial plateau and distal femur fractures. Currently, MRI is the study of choice for evaluation of bone marrow, internal derangements, and other soft-tissue injuries about the knee joint. In patients with knee dislocations, MR angiography may be performed simultaneously with MRI for evaluation of internal derangements and vascular injuries with less morbidity compared to conventional angiography. 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.

ACR Appropriateness Criteria® Acute Trauma to the Foot.

Acute injuries to the foot are frequently encountered in the emergency room and in general practice settings. This publication defines best practices for imaging evaluations for several variants of patients presenting with acute foot trauma. The variants include scenarios when the Ottawa rules can be evaluated, when there are exclusionary criteria, and when suspected pathology is in anatomic areas not addressed by the Ottawa rules. 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.

Bone Marrow Edema at Dual-Energy CT: A Game Changer in the Emergency Department.

Dual-energy CT is increasingly being used in the emergency department to help diagnose acute conditions. Its applications include demonstrating bone marrow edema (BME) seen in the setting of occult fractures and other acute conditions. Dual-energy CT acquires data with two different x-ray energy spectra and is able to help differentiate materials on the basis of their differential energy-dependent x-ray absorption behaviors. Virtual noncalcium (VNCa) techniques can be used to suppress the high attenuation of trabecular bone, thus enabling visualization of subtle changes in the underlying attenuation of the bone marrow. Visualization of BME can be used to identify occult or mildly displaced fractures, pathologic fractures, metastases, and some less commonly visualized conditions such as ligamentous injuries or inflammatory arthritis. The authors' major focus is use of dual-energy CT as a diagnostic modality in the setting of trauma and to depict subtle or occult fractures. The authors also provide some scenarios in which dual-energy CT is used to help diagnose other acute conditions. The causes and pathophysiology of BME are reviewed. Dual-energy CT image acquisition and VNCa postprocessing techniques are also discussed, along with their applications in emergency settings. The authors present potential pitfalls and limitations of these techniques and their possible solutions.©RSNA, 2020.