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Osteochondritis dissecans (OCD) is a joint disorder that affects the articular cartilage and subchondral bone, most commonly at the knee. OCD of the sacroiliac joint is extremely rare. Management of OCD remains controversial, and surgery is often needed, especially when conservative treatment fails. We present a rare case of OCD involving the left sacroiliac joint successfully treated by percutaneous computed tomography-guided retrograde drilling and debridement. [ABSTRACT FROM AUTHOR]

Objective: To report the magnetic resonance imaging (MRI) findings in athletic injuries of the extensor carpi ulnaris (ECU) subsheath, assessing the utility of gadolinium-enhanced (Gd) fat-saturated (FS) T1-weighted sequences with wrist pronation and supination.Methods: Sixteen patients (13 male, three female; mean age 30.3 years) with athletic injuries of the ECU subsheath sustained between January 2003 and June 2009 were included in this retrospective study. Initial and follow-up 1.5-T wrist MRIs were performed with transverse T1-weighted and STIR sequences in pronation, and Gd FS T1-weighted sequences with wrist pronation and supination. Two radiologists assessed the type of injury (A to C), ECU tendon stability, associated lesions and rated pulse sequences using a three-point scale: 1=poor, 2=good and 3=excellent.Results: Gd-enhanced FS T1-weighted transverse sequences in supination (2.63) and pronation (2.56) were most valuable, compared with STIR (2.19) and T1-weighted (1.94). Nine type A, one type B and six type C injuries were found. There were trends towards diminution in size, signal intensity and enhancement of associated pouches on follow-up MRI and tendon stabilisation within the ulnar groove.Conclusion: Gd-enhanced FS T1-weighted sequences with wrist pronation and supination are most valuable in assessing and follow-up athletic injuries of the ECU subsheath on 1.5-T MRI. [ABSTRACT FROM AUTHOR]

Objective: To report the biopsy findings of osteoid osteoma (OO) and OO-mimicking lesions, assess their distinctive multidetector computed tomography (MDCT) features and evaluate treatment by radiofrequency ablation (RFA).Methods: In this multicentric retrospective study, 80 patients (54 male, 26 female, mean age 24.1 years, range 5-48) with presumed (clinical and MDCT features) OO were treated by percutaneous RFA between May 2002 and June 2009. Per-procedural biopsies were always performed. The following MDCT features were assessed: skeletal distribution and location within the bone, size, central calcification, surrounding osteosclerosis and periosteal reaction. Clinical success of RFA was evaluated.Results: Histopathological diagnoses were: 54 inconclusive biopsies, 16 OO, 10 OO-mimicking lesions (5 chronic osteomyelitis, 3 chondroblastoma, 1 eosinophilic granuloma, 1 fibrous dysplasia). OO-mimicking lesions were significantly greater in size (p = 0.001) and presented non-significant trends towards medullary location (p = 0.246), moderate surrounding osteosclerosis (p = 0.189) and less periosteal reaction (p = 0.197), compared with OO. Primary success for ablation of OO-mimicking lesions was 100% at 1 month, 85.7% at 6 and 12 months, and 66.7% at 24 months. Secondary success was 100%.Conclusion: Larger size, medullary location, less surrounding osteosclerosis and periosteal reaction on MDCT may help differentiate OO-mimicking lesions from OO. OO-mimicking lesions are safely and successfully treated by RFA. [ABSTRACT FROM AUTHOR]

In musculoskeletal imaging, CT is used in a wide range of indications, either alone or in a synergistic approach with MRI. While MRI is the preferred modality for the assessment of soft tissues and bone marrow, CT excels in the imaging of high-contrast structures, such as mineralized tissue. Additionally, the introduction of dual-energy CT in clinical practice two decades ago opened the door for spectral imaging applications. Recently, the advent of photon-counting detectors (PCDs) has further advanced the potential of CT, at least in theory. Compared to conventional energy-integrating detectors (EIDs), PCDs provide superior spatial resolution, reduced noise, and intrinsic spectral imaging capabilities. This review briefly describes the technical advantages of PCDs. For each technical feature, the corresponding applications in musculoskeletal imaging will be discussed, including high-spatial resolution imaging for the assessment of bone and crystal deposits, low-dose applications such as whole-body CT, as well as spectral imaging applications including the characterization of crystal deposits and imaging of metal hardware. Finally, we will highlight the potential of PCD-CT in emerging applications, underscoring the need for further preclinical and clinical validation to unleash its full clinical potential., (© 2024. The Author(s).)

Objectives: To develop and validate an open-source deep learning model for automatically quantifying scapular and glenoid morphology using CT images of normal subjects and patients with glenohumeral osteoarthritis., Materials and Methods: First, we used deep learning to segment the scapula from CT images and then to identify the location of 13 landmarks on the scapula, 9 of them to establish a coordinate system unaffected by osteoarthritis-related changes, and the remaining 4 landmarks on the glenoid cavity to determine the glenoid size and orientation in this scapular coordinate system. The glenoid version, glenoid inclination, critical shoulder angle, glenopolar angle, glenoid height, and glenoid width were subsequently measured in this coordinate system. A 5-fold cross-validation was performed to evaluate the performance of this approach on 60 normal/non-osteoarthritic and 56 pathological/osteoarthritic scapulae., Results: The Dice similarity coefficient between manual and automatic scapular segmentations exceeded 0.97 in both normal and pathological cases. The average error in automatic scapular and glenoid landmark positioning ranged between 1 and 2.5 mm and was comparable between the automatic method and human raters. The automatic method provided acceptable estimates of glenoid version (R 2  = 0.95), glenoid inclination (R 2  = 0.93), critical shoulder angle (R 2  = 0.95), glenopolar angle (R 2  = 0.90), glenoid height (R 2  = 0.88) and width (R 2  = 0.94). However, a significant difference was found for glenoid inclination between manual and automatic measurements (p < 0.001)., Conclusions: This open-source deep learning model enables the automatic quantification of scapular and glenoid morphology from CT scans of patients with glenohumeral osteoarthritis, with sufficient accuracy for clinical use., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective: The study objective was to examine the disease, demographic, and imaging features associated with different inflammatory phenotypes of calcium pyrophosphate deposition (CPPD) disease, ie, recurrent acute calcium pyrophosphate (CPP) crystal arthritis, chronic CPP crystal inflammatory arthritis, and crowned dens syndrome (CDS)., Methods: Data from an international cohort (assembled from 25 sites in 7 countries for the development and validation of the 2023 CPPD classification criteria from the American College of Rheumatology/EULAR) that met the criteria were included. Three cross-sectional studies were conducted to determine the phenotypic characteristics of recurrent acute CPP crystal arthritis, chronic CPP crystal inflammatory arthritis, and CDS. Multivariable logistic regression analysis was used to calculate adjusted odds ratio (aOR) and 95% confidence interval (CI) to examine the association between potential risk factors and the inflammatory phenotype., Results: Among the 618 people included (56% female; mean age [standard deviation] 74.0 [11.9] years), 602 (97.4%) had experienced acute CPP crystal arthritis, 332 (53.7%) had recurrent acute arthritis, 158 (25.6%) had persistent inflammatory arthritis, and 45 (7.3%) had had CDS. Recurrent acute CPP crystal arthritis associated with longer disease duration (aOR 2.88 [95% CI 2.00-4.14]). Chronic CPP crystal inflammatory arthritis was associated with acute wrist arthritis (aOR 2.92 [95% CI 1.81-4.73]), metacarpophalangeal joint osteoarthritis (aOR 1.87 [95% CI 1.17-2.97]), and scapho-trapezo-trapezoid (STT) joint osteoarthritis (aOR 1.83 [95% CI 1.15-2.91]), and it was negatively associated with either metabolic or familial risk for CPPD (aOR 0.60 [95% CI 0.37-0.96]). CDS was associated with male sex (aOR 2.35 [95% CI 1.21-4.59]), STT joint osteoarthritis (aOR 2.71 [95% CI 1.22-6.05]), and more joints affected with chondrocalcinosis (aOR 1.46 [95% CI 1.15-1.85])., Conclusion: CPPD disease encompasses acute and chronic inflammatory phenotypes, each with specific clinical and imaging features that need to be considered in the diagnostic workup., (© 2024 The Author(s). Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Objectives: Apply a modified Delphi-based approach and produce a practical, radiology-specific set of definitions for interpretation and standardization of the multiple MRI findings in axial spondyloarthritis (ax-SpA), specifically to aid the general radiologist with a musculoskeletal interest, working with gold standard basic MRI protocols., Materials and Methods: We report the results of a modified Delphi-based consensus of 35 experts from 13 countries in the Arthritis Subcommittee of the European Society of Musculoskeletal Radiology (ESSR). Seventeen definitions were created (i.e., nine for the spine and eight for the sacroiliac joint) and two Delphi rounds were conducted on an electronic database, collated and revised by the project leader with agreement. Group leads were appointed for each definition following the first round. Final definitions included only those that reached a consensus > 80%; if > 50% agreed on exclusion consensus, definitions were excluded. Final results have been shared during the Arthritis meeting at the Annual ESSR Congress., Results: Fourteen definitions, eight for the spine and six for the sacroiliac joint were agreed for standardized reporting. Andersson's, anterior corner sclerotic and costovertebral joint inflammatory lesions of the spine, with active and non-active erosions, and fat metaplasia of the sacroiliac joint reaching the highest consensus (≥ 95%). More than 50% of the experts agreed to exclude joint space inflammation in the sacroiliac joint and tissue backfill. Syndesmophytes reached 76% agreement., Conclusions: Agreed definitions by expert radiologists using a modified Delphi process, should allow standardized actionable radiology reports and clarity in reporting terminology of ax-SpA., Clinical Relevance Statement: The proposed definitions will support reporting from musculoskeletal and general radiologists working with gold-standard basic MRI, improve confidence in lesion assessment, and standardize terminology to provide actionable reports on MRI in patients with ax-SpA., Key Points: Experts applied a modified Delphi method to optimize the definitions of MRI findings of ax-SpA. After two Delphi rounds and one in-person meeting, fourteen definitions reached the agreement threshold. These consensus-based definitions will aid in actionable reporting specifically for the general radiologist with a musculoskeletal interest., (© 2024. Crown.)

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., (© 2024 American College of Rheumatology.)

Objective: Monosodium-urate (MSU) crystal deposits can be visualized and quantified with dual-energy CT (DECT). Pegloticase lowers serum urate (SU) in uncontrolled gout patients, with methotrexate (MTX) co-therapy recommended to increase SU-lowering response rate and decrease infusion reaction risk. The literature on serial DECT-imaging during pegloticase+MTX co-therapy is sparse, with only 2 prior cases of rapid MSU deposition depletion with subsequent bone-erosion remodeling reported from a small open-label trial. Here, we report DECT findings during pegloticase treatment in a larger number of patients from a randomized controlled trial to confirm bone-erosion remodeling that follows MSU depletion with pegloticase. The influence of length-of-therapy is also explored., Methods: Patients received pegloticase (8mg every 2weeks)+MTX (15mg/week orally) or pegloticase+placebo (PBO) during the MIRROR RCT trial. A subset underwent DECT-imaging on Day1 (first pegloticase infusion) and at Weeks 14, 24, and 52. Patients with paired baseline-Week 52 images were included. Imaged regions with baseline MSU-crystal volume (V MSU )<0.5cm 3 were excluded to minimize artifact contributions. V MSU and bone-erosion remodeling were assessed., Results: Eight patients (6 MTX, 2 PBO) were included. Included patients had received 52weeks (5 MTX), 42weeks (1 PBO), and 6weeks (1 MTX, 1 PBO) of pegloticase therapy. Patients who prematurely discontinued pegloticase maintained SU<6mg/dL on allopurinol (n=2)/febuxostat (n=1). At Week 52, V MSU had markedly decreased in both the pegloticase+MTX and pegloticase+PBO treatment groups, with faster depletion during pegloticase therapy. Bone-erosion remodeling was observed in 29/42 (69%) evaluated erosions: 29 (69%) size decrease, 4 (9.5%) recortication, 3 (7.1%) new bone formation., Conclusion: Rapid V MSU depletion during pegloticase therapy was observed with concomitant bone remodeling within 1year. Following pegloticase discontinuation, V MSU reduction slowed or stopped even when SU was maintained<6mg/dL with oral ULT., Clinical Trial Registration: NCT03994731., (Copyright © 2024 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

Objective: Intra-articular (IA) mineralization may contribute to osteoarthritis (OA) structural progression. We studied the association of IA mineralization on knee computed tomography (CT) with cartilage damage worsening on knee magnetic resonance imaging (MRI), with a focus on location- and tissue-specific effects., Methods: Participants from the Multicenter Osteoarthritis Study with knee CT and MRI scans were included. Presence of IA mineralization on CT was defined as a Boston University Calcium Knee Score >0 anywhere in the knee. Cartilage worsening on MRI was defined as any increase in the MRI OA Knee Score, including incident damage. We evaluated the association of whole-knee, compartment-specific (ie, medial or lateral), and subregion-specific (ie, location-matched) IA mineralization at baseline with cartilage worsening at two years' follow-up in the corresponding locations using binomial regression with generalized estimating equations, adjusting for age, sex, and body mass index (BMI)., Results: We included 1,673 participants (mean age 60 years, 56% female, mean BMI 29). Nine percent had any IA mineralization in the knee, and 47.4% had any cartilage worsening on follow-up. Mineralization of any tissue in the knee, regardless of location, was not associated with MRI cartilage worsening. However, cartilage mineralization was associated with 1.39 (95% confidence interval 1.04-1.88) times higher risk of cartilage worsening in the same compartment, with similar results in subregion-specific analysis., Conclusion: CT-detected IA mineralization in the cartilage was associated with higher risk of MRI cartilage worsening in the same compartment and subregion over two years. These findings suggest potential localized, tissue-specific effects of IA mineralization on cartilage pathology in knee OA., (© 2024 American College of Rheumatology.)

Objective: Patients with gout are at elevated risk of multiple vascular and metabolic comorbidities. Whether they are also at risk of sarcopenia, which is known to affect patients with other rheumatic diseases, has not been previously assessed. We examined whether patients with gout have decreased lumbar muscle quality and quantity, indicating an association between gout and sarcopenia., Methods: Fifty gout subjects and 25 controls, ages 45-80, underwent computed tomography imaging of the lumbosacral spine. We measured muscle quantity (skeletal muscle area [SMA] and index [SMI]) and quality (skeletal muscle radiation attenuation [SMRA] and intermuscular adipose tissue [IMAT] area and index [IMATI]) of the psoas and erector spinae muscles at the L3 level., Results: Seventy subjects (45 gout and 25 controls) were included in the analysis. Gout subjects had higher BMI, more kidney disease and hypertension, lower exercise frequency, and higher mean serum urate and creatinine vs. controls. Lumbar SMRA was significantly lower in gout subjects vs. controls, indicating reduced muscle quality. Lumbar IMAT area was significantly higher in gout subjects vs. controls, as was lumbar IMATI, indicating increased muscle adiposity. These differences persisted after adjusting for potential confounders. In contrast, there was no significant difference between gout and control groups in lumbar SMA or lumbar SMI, suggesting that muscle quantity may not be routinely affected by the diagnosis of gout., Conclusions: Gout patients exhibit decreased lumbar muscle quality compared with controls, consistent with an association between gout and sarcopenia., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Objective: To formulate evidence-based recommendations and overarching principles on the use of imaging in the clinical management of crystal-induced arthropathies (CiAs)., Methods: An international task force of 25 rheumatologists, radiologists, methodologists, healthcare professionals and patient research partners from 11 countries was formed according to the EULAR standard operating procedures. Fourteen key questions on the role of imaging in the most common forms of CiA were generated. The CiA assessed included gout, calcium pyrophosphate deposition disease and basic calcium phosphate deposition disease. Imaging modalities included conventional radiography, ultrasound, CT and MRI. Experts applied research evidence obtained from four systematic literature reviews using MEDLINE, EMBASE and CENTRAL. Task force members provided level of agreement (LoA) anonymously by using a Numerical Rating Scale from 0 to 10., Results: Five overarching principles and 10 recommendations were developed encompassing the role of imaging in various aspects of patient management: making a diagnosis of CiA, monitoring inflammation and damage, predicting outcome, response to treatment, guided interventions and patient education. Overall, the LoA for the recommendations was high (8.46-9.92)., Conclusions: These are the first recommendations that encompass the major forms of CiA and guide the use of common imaging modalities in this disease group in clinical practice., Competing Interests: Competing interests: AA has received institutional research grants from AstraZeneca and Oxford Immunotech, royalty from UpToDate and Springer, lecture fees from Cadilla Pharmaceuticals, consulting fees from NGM Bio Limbic and Inflazome, all unrelated to the present work. AI has received honoraria, speaker fees and grants from AbbVie, Alfa-sigma, BMS, Celgene, Celltrion, Eli Lilly, Galapagos, Gilead, Janssen, MSD, Novartis, Pfizer, Sanofi Genzyme and Sobi. FB has received consulting fees from Horizon and has a research agreement with Siemens Healthineers. FP has received grants and personal fees from Novartis, Eli Lilly and UCB, and personal fees from AbbVie, Amgen, BMS, Celgene, Janssen, Hexal, Medscape, MSD, Pfizer and Roche outside the presented work. FP-R has received consulting fees from Arthrosi, Horizon, LG Pharma and Protalix; speaker fees from Horizon and Menarini; research grants from Cruces Rheumatology Association; fees in relation to trial committee or DMSB and Selecta-Sobi; and is on the steering committee of LG Pharma. HBH has received honorary for teaching from AbbVie, UCB, Lilly and Novartis and for participating in advisory boards from AbbVie and Novartis. JR has received unrestricted research grant from Sobi and Novartis, and speaker honoraria and consulting fees from BMS, Novartis and Sobi. LMS has received funding from Esaote SPA, Samsung Medison, GE HealthCare, Pfizer, Abiogen, AbbVie, Janssen-Cilag, Novartis, MSD, Merck Serono, Fidia Farmaceutici, RAW and EchoLight. LT has received speaker fees from Janssen, Novartis, GE and Eli Lilly, and is on the advisory board for UCB and Janssen. MAD'A has received speaker or consultant fees from Novartis, BMS, Janssen, Amgen, Boehringer Ingelheim, AbbVie, AstraZeneca, Pfizer, UCB and Eli Lilly. ND has received consulting fees, speaker fees or grants from AstraZeneca, Novartis, Horizon, Selecta, Arthrosi, JW Pharmaceutical Corporation, PK Med, LG Chem, JPI, PTC Therapeutics, Protalix, Unlocked Labs and Hikma. TP has received honorary from Novartis and research grants from Horizon Pharmaceuticals. VN-C has received consulting fees from AbbVie, Galapagos, Lilly, Novartis, Lilly, Pfizer and UCB, and speaker fees from AbbVie, Fresenius, Lilly, Novartis, Pfizer and UCB., (“© European Alliance of Associations for Rheumatology, EULAR 2024. Re-use permitted under CC BY-NC-ND. No commercial re-use. No derivatives. See rights and permissions. Published by BMJ on behalf of EULAR.”.)

Background: Static posterior subluxation of the humeral head (SPSH) results in glenohumeral osteoarthritis. Treatment strategies for SPSH with or without resulting osteoarthritis remain challenging. There is growing interest in evaluating the rotator cuff muscle volume, fatty infiltration, or forces in osteoarthritic shoulders with SPSH, mainly due to a possible transverse force imbalance. In nonpathological shoulders, the transverse angle of the rotator cuff muscle's resultant force may be associated with scapulohumeral alignment and glenoid vault morphology, despite an assumed transverse force balance. The purpose of this study was to assess the transverse rotator cuff muscle's resultant force angle (TRFA) and its relationship with the scapulohumeral subluxation index (SHSI) and selected glenoid vault parameters using computer modeling., Methods: Computed tomography scans of 55 trauma patients (age 31 ± 13 years, 36 males) with nonpathological shoulders were analyzed and all measurements performed in 3-dimension. We placed landmarks manually to determine the humeral head center and the rotator cuff tendon footprints. The contours of the rotator cuff muscle cross-sectional areas were automatically predicted in a plane perpendicular to the scapula. Each rotator cuff muscle was divided into virtual vector fibers with homogeneous density. The resultant force vector direction for each muscle, corresponding to the rotator cuff action line, was calculated by vectorially summing the normalized fiber vectors for each muscle, weighted by the muscle trophic ratio. The resultant force vector was projected on the axial plane, and its angle with the mediolateral scapular axis was used to determine TRFA. The SHSI according to Walch, glenoid version angle (GVA), glenoid anteroposterior offset angle (GOA), glenoid depth, glenoid width, and glenoid radius were also evaluated., Results: The mean values for TRFA, SHSI, GVA, GOA, glenoid depth, glenoid width, and glenoid radius were 7.4 ± 4.5°, 54.3 ± 4.8%, -4.1 ± 4.4°, 5.1 ± 10.8°, 3.3 ± 0.6 mm, 20 ± 2 mm, and 33.6 ± 4.6 mm, respectively. The TRFA correlated strongly with SHSI (R = 0.731, P < .001) and GVA (R = 0.716, P < .001) and moderately with GOA (R = 0.663, P < .001). The SHSI was strongly negatively correlated with GVA (R = -0.813, P < .001) and moderately with GOA (R = -0.552, P < .001). The GVA correlated strongly with GOA (R = 0.768, P < .001). In contrast, TRFA, SHSI, GVA, and GOA did not correlate with glenoid depth, width, or radius., Conclusion: Despite an assumed balance in the transverse volume of the rotator cuff muscles in nonpathological shoulders, variations exist regarding the transverse resultant force depending on the SHSI, GVA, and GOA. In healthy/nonosteoarthritic shoulders, an increased glenoid retroversion is associated with a decreased anterior glenoid offset., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

When a low-energy trauma induces an acute vertebral fracture (VF) with clinical symptoms, a definitive diagnosis of osteoporotic vertebral fracture (OVF) can be made. Beyond that, a "gold" radiographic standard to distinguish osteoporotic from non-osteoporotic VFs does not exist. Fracture-shaped vertebral deformity (FSVD) is defined as a deformity radiographically indistinguishable from vertebral fracture according to the best of the reading radiologist's knowledge. FSVD is not uncommon among young populations with normal bone strength. FSVD among an older population is called osteoporotic-like vertebral fracture (OLVF) when the FSVD is likely to be associated with compromised bone strength. In more severe grade deformities or when a vertebra is collapsed, OVF diagnosis can be made with a relatively high degree of certainty by experienced readers. In "milder" cases, OVF is often diagnosed based on a high probability rather than an absolute diagnosis. After excluding known mimickers, singular vertebral wedging in older women is statistically most likely an OLVF. For older women, three non-adjacent minimal grade OLVF (< 20% height loss), one minimal grade OLVF and one mild OLVF (20-25% height loss), or one OLVF with ≥ 25% height loss, meet the diagnosis of osteoporosis. For older men, a single OLVF with < 40% height loss may be insufficient to suggest the subject is osteoporotic. Common OLVF differential diagnoses include X-ray projection artifacts and scoliosis, acquired and developmental short vertebrae, osteoarthritic wedging, oncological deformities, deformity due to high-energy trauma VF, lateral hyperosteogeny of a vertebral body, Cupid's bow, and expansive endplate, among others., (© 2024. The Author(s).)

Background: Immune checkpoint inhibitors (ICIs) are reshaping the prognosis of many cancers, but often cause immune-related adverse events (irAEs). Among neurological irAEs, myositis is the most frequently reported. Our aim is to describe clinical and non-clinical characteristics, treatment and outcome of all irMyositis (skeletal limb-girdle and/or ocular myositis) and irMyocarditis cases in our reference center., Methods: We retrospectively enrolled all irMyositis/irMyocarditis patients seen between 2018 and 2022. We reviewed demographics, clinical characteristics, biological, neurophysiological, imaging workup, treatment and outcome., Results: We included 14 consecutive patients. The most frequent treatments were pembrolizumab (35%) or ipilimumab-nivolumab combination (35%). Limb-girdle, ocular (non-fluctuating palpebral ptosis and/or diplopia with or without ophthalmoparesis) and cardiac phenotypes were equally distributed, overlapping in 40% of cases. Ocular involvement was frequently misdiagnosed; review of brain MRIs disclosed initially missed signs of skeletal myositis in one patient and ocular myositis in 3. Seven patients had other co-existing irAEs. When performed, myography showed a myogenic pattern. CK was elevated in 8/15 patients, troponin-T in 12/12 and troponin-I in 7/9 tested patients. ICI were discontinued in all cases, with further immunosuppressive treatment in nine patients. In most cases, neurological and cardiological outcome was good at last follow-up., Conclusion: Myositis is a potentially severe irAE. Despite its heterogeneous presentation, some highly suggestive clinical symptoms, such as ocular involvement, or radiological signs should raise physicians' attention to avoid misdiagnosis. We thus recommend a multidisciplinary assessment (including complete neuromuscular evaluation) even in case of isolated myocarditis. Our series underlines the importance of an early diagnosis, since suspension of ICI and adequate treatment are usually associated with good functional outcome., (© 2023. The Author(s).)

Deep learning models (DLM) are efficient replacements for computationally intensive optimization techniques. Musculoskeletal models (MSM) typically involve resource-intensive optimization processes for determining joint and muscle forces. Consequently, DLM could predict MSM results and reduce computational costs. Within the total shoulder arthroplasty (TSA) domain, the glenohumeral joint force represents a critical MSM outcome as it can influence joint function, joint stability, and implant durability. Here, we aimed to employ deep learning techniques to predict both the magnitude and direction of the glenohumeral joint force. To achieve this, 959 virtual subjects were generated using the Markov-Chain Monte-Carlo method, providing patient-specific parameters from an existing clinical registry. A DLM was constructed to predict the glenohumeral joint force components within the scapula coordinate system for the generated subjects with a coefficient of determination of 0.97, 0.98, and 0.98 for the three components of the glenohumeral joint force. The corresponding mean absolute errors were 11.1, 12.2, and 15.0 N, which were about 2% of the maximum glenohumeral joint force. In conclusion, DLM maintains a comparable level of reliability in glenohumeral joint force estimation with MSM, while drastically reducing the computational costs., Competing Interests: Declaration of competing interest The authors declare that they have no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

People with late-stage Parkinson's disease (PD) often suffer from debilitating locomotor deficits that are resistant to currently available therapies. To alleviate these deficits, we developed a neuroprosthesis operating in closed loop that targets the dorsal root entry zones innervating lumbosacral segments to reproduce the natural spatiotemporal activation of the lumbosacral spinal cord during walking. We first developed this neuroprosthesis in a non-human primate model that replicates locomotor deficits due to PD. This neuroprosthesis not only alleviated locomotor deficits but also restored skilled walking in this model. We then implanted the neuroprosthesis in a 62-year-old male with a 30-year history of PD who presented with severe gait impairments and frequent falls that were medically refractory to currently available therapies. We found that the neuroprosthesis interacted synergistically with deep brain stimulation of the subthalamic nucleus and dopaminergic replacement therapies to alleviate asymmetry and promote longer steps, improve balance and reduce freezing of gait. This neuroprosthesis opens new perspectives to reduce the severity of locomotor deficits in people with PD., (© 2023. The Author(s), under exclusive licence to Springer Nature America, Inc.)

This opinion article by the European Society of Musculoskeletal Radiology Arthritis and Pediatric Subcommittees discusses the current use of conventional radiography (CR) of the sacroiliac joints in adults and juveniles with suspected axial spondyloarthritis (axSpA). The strengths and limitations of CR compared with magnetic resonance imaging (MRI) and computed tomography (CT) are presented.Based on the current literature and expert opinions, the subcommittees recognize the superior sensitivity of MRI to detect early sacroiliitis. In adults, supplementary pelvic radiography, low-dose CT, or synthetic CT may be needed to evaluate differential diagnoses. CR remains the method of choice to detect structural changes in patients with suspected late-stage axSpA or established disease and in patients with suspected concomitant hip or pubic symphysis involvement. In children, MRI is the imaging modality of choice because it can detect active as well as structural changes and is radiation free., Competing Interests: None declared., (Thieme. All rights reserved.)

Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Objective: Calcium pyrophosphate deposition (CPPD) disease is prevalent and has diverse presentations, but there are no validated classification criteria for this symptomatic arthritis. The American College of Rheumatology (ACR) and EULAR have developed the first-ever validated classification criteria for symptomatic CPPD disease., Methods: Supported by the ACR and EULAR, a multinational group of investigators followed established methodology to develop these disease classification criteria. The group generated lists of candidate items and refined their definitions, collected de-identified patient profiles, evaluated strengths of associations between candidate items and CPPD disease, developed a classification criteria framework, and used multi-criterion decision analysis to define criteria weights and a classification threshold score. The criteria were validated in an independent cohort., Results: Among patients with joint pain, swelling, or tenderness (entry criterion) whose symptoms are not fully explained by an alternative disease (exclusion criterion), the presence of crowned dens syndrome or calcium pyrophosphate crystals in synovial fluid are sufficient to classify a patient as having CPPD disease. In the absence of these findings, a score >56 points using weighted criteria, comprising clinical features, associated metabolic disorders, and results of laboratory and imaging investigations, can be used to classify as CPPD disease. These criteria had a sensitivity of 92.2% and specificity of 87.9% in the derivation cohort (190 CPPD cases, 148 mimickers), whereas sensitivity was 99.2% and specificity was 92.5% in the validation cohort (251 CPPD cases, 162 mimickers)., Conclusion: The 2023 ACR/EULAR CPPD disease classification criteria have excellent performance characteristics and will facilitate research in this field., (© 2023 The Authors. Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Objectives: The purpose of this agreement was to establish evidence-based consensus statements on imaging of distal radioulnar joint (DRUJ) instability and triangular fibrocartilage complex (TFCC) injuries by an expert group using the Delphi technique., Methods: Nineteen hand surgeons developed a preliminary list of questions on DRUJ instability and TFCC injuries. Radiologists created statements based on the literature and the authors' clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panelists consisted of twenty-seven musculoskeletal radiologists. The panelists scored their degree of agreement to each statement on an 11-item numeric scale. Scores of "0," "5," and "10" reflected complete disagreement, indeterminate agreement, and complete agreement, respectively. Group consensus was defined as a score of "8" or higher for 80% or more of the panelists., Results: Three of fourteen statements achieved group consensus in the first Delphi round and ten statements achieved group consensus in the second Delphi round. The third and final Delphi round was limited to the one question that did not achieve group consensus in the previous rounds., Conclusions: Delphi-based agreements suggest that CT with static axial slices in neutral rotation, pronation, and supination is the most useful and accurate imaging technique for the work-up of DRUJ instability. MRI is the most valuable technique in the diagnosis of TFCC lesions. The main indication for MR arthrography and CT arthrography are Palmer 1B foveal lesions of the TFCC., Clinical Relevance Statement: MRI is the method of choice for assessing TFCC lesions, with higher accuracy for central than peripheral abnormalities. The main indication for MR arthrography is the evaluation of TFCC foveal insertion lesions and peripheral non-Palmer injuries., Key Points: • Conventional radiography should be the initial imaging technique in the assessment of DRUJ instability. CT with static axial slices in neutral rotation, pronation, and supination is the most accurate method for evaluating DRUJ instability. • MRI is the most useful technique in diagnosing soft-tissue injuries causing DRUJ instability, especially TFCC lesions. • The main indications for MR arthrography and CT arthrography are foveal lesions of the TFCC., (© 2023. The Author(s), under exclusive licence to European Society of Radiology.)

Background: The Calcium Pyrophosphate Deposition (CPPD) subgroup of the Outcome Measures in Rheumatology (OMERACT) Ultrasound working group was established to validate ultrasound as an outcome measure instrument for CPPD, and in 2017 has developed and validated standardised definitions for elementary lesions for the detection of calcium pyrophosphate crystals in joints. The aim of this study was to develop and evaluate the reliability of a consensus-based ultrasound scoring system for CPPD extent, representing the next phase in the OMERACT methodology., Methods: In this study the novel scoring system for CPPD was developed through a stepwise process, following an established OMERACT ultrasound methodology. Following a previous systematic review to gather available evidence on existing scoring systems for CPPD, the novel scoring system was developed through a Delphi survey based on the expert opinion of the members of the OMERACT Ultrasound working group-CPPD subgroup. The reliability of the scoring system was then tested on a web-based and patient-based exercise. Intra-reader and inter-reader reliability of the new scoring system was assessed using weighted Light's κ coefficients., Findings: The four-grade semiquantitative scoring system consisted of: grade 0 (no findings consistent with CPPD), grade 1 (≤3 single spots or 1 small deposit), grade 2 (>3 single spots or >1 small deposit or ≥1 larger deposit occupying ≤50% of the structure under examination in the reference image-ie, the scanning view with the highest grade of depositions), and grade 3 (deposits that occupy more than 50% of the structure under examination in the reference image). The score should be applied to the knee (menisci and hyaline cartilage) and the triangular fibrocartilage complex of the wrist. The intra-reader and inter-reader reliabilities on static images were almost perfect (κ 0·90 [95% CI 0·79-1·00] and κ 0·84 [0·79-0·88]), and on the eight patients recruited (four [50%] female and four [50%] male) were substantial (κ 0·72 [95% CI 0·47 to 0·96] and 0·66 [0·61 to 0·71])., Interpretation: This OMERACT ultrasound scoring system for CPPD was reliable on both static images and patients. The scoring system might be a valuable tool for ensuring valid and comparable results in clinical trials and could help monitor the extent of crystal deposition in patients with CPPD in clinical practice., Funding: The Italian Ministry of Health - Ricerca Corrente., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Purpose: To assess the role of preoperative CT-based skeletal muscle mass depletion on postoperative clinical outcomes and survival in patients who underwent total laryngectomy for cancer., Methods: Patients operated on between January 2011 and March 2020 were retrospectively included. Skeletal muscle area and intra- and inter-muscular fat accumulation were measured at the third lumbar vertebral level on preoperative CT scans. Skeletal muscle mass depletion was defined based on pre-established cut-off values. Their association with postoperative morbidity, length of stay (LOS), costs, and survival was assessed., Results: A total of 84 patients were included, of which 37 (44%) had preoperative skeletal muscle mass depletion. The rate of postoperative fistula (23% vs. 35%, p = 0.348), cutaneous cervical dehiscence (17% vs. 11%, p = 0.629), superficial incisional surgical site infections (SSI) (12% vs. 10%, p = 1.000), and unplanned reoperation (38% vs. 37%, p = 1.000) were comparable between the two patient groups. No difference in median LOS was observed (41 vs. 33 days, p = 0.295), nor in treatment costs (119,976 vs. 109,402 CHF, p = 0.585). The median overall survival was comparable between the two groups (3.43 vs. 4.95 years, p = 0.09)., Conclusions: Skeletal muscle mass depletion alone had no significant impact on postoperative clinical outcomes or survival.

Background: Colchicine has been suggested for osteoarthritis treatment, but evidence is contradictory. We aimed to investigate colchicine's efficacy and safety compared with placebo in people with hand osteoarthritis., Methods: In this single-centre, double-blind, randomised, placebo-controlled trial we recruited adults with symptomatic hand osteoarthritis and finger pain of at least 40 mm on a 100 mm visual analogue scale from an outpatient clinic in Denmark. The hand with the most severe finger pain at inclusion was the target hand. Participants were randomly assigned (1:1) to 0·5 mg colchicine or placebo taken orally twice a day for 12 weeks, stratified by BMI (≥30 kg/m 2 ), sex, and age (≥75 years). Participants, outcome assessors, and data analysts were masked to treatment allocation. The primary endpoint was change from baseline to week 12 in target hand finger pain, assessed on a 100 mm visual analogue scale with a pre-specified minimal clinically important difference of 15 mm, in the intention-to-treat population. Safety was assessed at week 12 in the intention-to-treat population. The study was registered with ClinicalTrials.gov, NCT04601883, and with EudraCT, 2020-002803-20., Findings: Between Jan 15, 2021, and March 3, 2022, 186 people were screened for eligibility, and 100 were randomly assigned to receive colchicine (n=50) or placebo (n=50). Participants had a mean age of 70·9 (SD 7·5) years, 69 (69%) of 100 were women and 31 (31%) were men. All participants completed the study. The mean change from baseline to week 12 in finger pain were -13·9 mm (SE 2·8) in the colchicine group and -13·5 mm (2·8) in the placebo group, with a between-group difference (colchicine vs placebo) of -0·4 mm (95% CI -7·6 to 6·7; p=0·90). In the colchicine group, there were 76 adverse events in 36 (72%) of 50 participants and one serious adverse advent (migraine attack leading to hospital admission). In the placebo group, there were 42 adverse events in 22 (44%) of 50 participants and two serious adverse events (cholecystitis and elevated alanine aminotransferase concentrations, in the same patient)., Interpretation: In people with painful hand osteoarthritis, treatment with 0·5 mg of colchicine twice day for 12 weeks did not effectively relieve pain, and treatment with colchicine was associated with more adverse events., Funding: The Oak Foundation, IMK Almene Fond, Minister Erna Hamilton's Scholarship for Science and Art, AP Moller and Wife Chastine McKinney Moller's Foundation for Medical Science Advancement, The Danish Medical Association, the Velux Foundation, Aase and Ejnar Danielsen's Foundation, and Director Emil C Hertz and Wife Inger Hertz's foundation., Competing Interests: Declaration of interests The Parker Institute is supported by a core grant from the Oak Foundation (OCAY-18–774-OFIL). AD has received grants to this project from IMK Almene Fond, Erna Hamilton's Foundation (Minister Erna Hamilton's Scholarship for Science and Art), the AP Møller Foundation (AP Møller and wife Chastine McKinney Møller's Foundation for Medical Science Advancement), The Danish Medical Association, the Velux Foundation, Aase and Ejnar Danielsen's Foundation and Director Emil C Hertz and wife Inger Hertz's foundation. FB has received consulting fees from Horizon Therapeutics. FCM has received grants from Innovation Fund Denmark; and payment or honoraria from Varian and Siemens Healthineers. IKH has received grants from Pfizer and Lily; and payment or honoraria from Novartis and GSK. LT has received payment or honoraria from Eli Lilly, Novartis, and Janssen; and is on the advisory board for Bristol Meyers Squibb and Janssen. MH is on the European Advisory Board for Thuasne Group. MK has received grants from the Innovative Medicines Initiative (APPROACH project) and Dutch Arthritis Society; royalties or licenses from Wolters Kluwer and Springer Verlag; consulting fees for Abbvie, Pfizer, Kiniksa, Flexion, Galapagos, Centre for Human Drug Research, Novartis, and UCB; payment or honoraria from Galapagos and Jansen; and is a member of the Osteoarthritis Research Society International board, a member of the European Alliance of Associations for Rheumatology (EULAR) council and President for the Dutch Society for Rheumatology. PGC has received consulting fees from AbbVie, AstraZeneca, Eli Lilly, Galapagos, GlaxoSmithKline, Grunenthal, Janssen, Levicept, Merck, Novartis, Pfizer, Regeneron, Stryker, and UCB; payment or honoraria from AbbVie; and support from AbbVie to congress attendance. LKS has received grants from the Health Reserach Council of New Zealand amd consulting fees from Pharmac. GMM has received support for attending meeting from Janssen; and is president for the Irish Society of Rheumatology. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background & Aims: Body composition is sex dependent and associated with an increased mortality risk in patients with cirrhosis. We evaluated whether it was also associated with short-term mortality in patients critically ill with acute-on-chronic liver failure (ACLF)., Patients and Methods: We retrospectively included all patients with cirrhosis and ACLF hospitalised in the intensive care unit (ICU) of Lausanne University Hospital between 2010 and 2019 for whom an abdominal computed tomography (CT) scan performed ±7 days from admission was available. Patients from the ICU of Paul Brousse University Hospital admitted between 2017 and 2020 served as an external cohort. All body composition parameters at the third lumbar vertebral level (L3) were quantified using a deep learning-based method., Results: In total, 192 patients from Lausanne were included. Median age was 62 years and 28-day survival rate was 58.2%. In males, variables independently associated with 28-day mortality on days 1 and 3 were Chronic Liver Failure Consortium (CLIF-C) ACLF-lactate and sarcopenia. In females, CLIF-C ACLF-lactate on days 1 and 3 was the only predictor of 28-day survival. We derived two scores combining sarcopenia and the CLIF-C ACLF-lactate score on days 1 and 3, with area under the receiver operating characteristic outperforming the CLIF-C ACLF-lactate score alone in male but not in female patients. Comparable results were found in the external cohort of 58 patients and supported the sex specificity of the performance of the model. Patients with sarcopenia had increased risks of invasive fungal infection and renal replacement therapy., Conclusion: Sarcopenia was associated with 28-day mortality in male but not in female patients critically ill with ACLF. Although screening for sarcopenia could impact the management of male patients, further studies are needed in female cohorts to investigate whether other body composition parameters are associated with outcomes., Impact and Implications: Body composition, easily assessed by CT, is altered in patients with cirrhosis and associated with outcome; it has never been investigated in patients critically ill with ACLF. The results of the present study, underlining the benefit of sarcopenia evaluation to improve prognosis prediction in males critically ill with ACLF, are of importance for physicians managing such patients to optimise the decision-making process toward continued treatment, liver transplantation, or limitation of care. In a wider sense, besides the number and course of organ failures, the results recall the weight of the general condition of males with ACLF at admission to ICU. In females critically ill with ACLF, in analyses limited by the sample size, none of the body composition parameters was associated with short-term mortality independently of organ failures; this suggests that the number and course of organ failures are the main determinant of mortality in these patients., Competing Interests: None of the contributing authors has any disclosures related to this work. Please refer to the accompanying ICMJE disclosure forms for further details., (© 2023 The Author(s).)

Objectives: To assess image noise, diagnostic performance, and potential for radiation dose reduction of photon-counting detector (PCD) computed tomography (CT) with quantum iterative reconstruction (QIR) in the detection of hypoattenuating and hyperattenuating focal liver lesions compared with energy-integrating detector (EID) CT., Materials and Methods: A medium-sized anthropomorphic abdominal phantom with liver parenchyma and lesions (diameter, 5-10 mm; hypoattenuating and hyperattenuating from -30 HU to +90 HU at 120 kVp) was used. The phantom was imaged on ( a ) a third-generation dual-source EID-CT (SOMATOM Force, Siemens Healthineers) in the dual-energy mode at 100 and 150 kVp with tin filtration and ( b ) a clinical dual-source PCD-CT at 120 kVp (NAEOTOM Alpha, Siemens). Scans were repeated 10 times for each of 3 different radiation doses of 5, 2.5, and 1.25 mGy. Datasets were reconstructed as virtual monoenergetic images (VMIs) at 60 keV for both scanners and as linear-blended images (LBIs) for EID-CT. For PCD-CT, VMIs were reconstructed with different strength levels of QIR (QIR 1-4) and without QIR (QIR-off). For EID-CT, VMIs and LBIs were reconstructed using advanced modeled iterative reconstruction at a strength level of 3. Noise power spectrum was measured to compare image noise magnitude and texture. A channelized Hotelling model observer was used to assess diagnostic accuracy for lesion detection. The potential for radiation dose reduction using PCD-CT was estimated for the QIR strength level with the highest area under the curve compared with EID-CT for each radiation dose., Results: Image noise decreased with increasing QIR level at all radiation doses. Using QIR-4, noise reduction was 41%, 45%, and 59% compared with EID-CT VMIs and 12%, 18%, and 33% compared with EID-CT LBIs at 5, 2.5, and 1.25 mGy, respectively. The peak spatial frequency shifted slightly to lower frequencies at higher QIR levels. Lesion detection accuracy increased at higher QIR levels and was higher for PCD-CT compared with EID-CT VMIs. The improvement in detection with PCD-CT was strongest at the lowest radiation dose, with an area under the receiver operating curve of 0.917 for QIR-4 versus 0.677 for EID-CT VMIs for hyperattenuating lesions, and 0.900 for QIR-4 versus 0.726 for EID-CT VMIs for hypoattenuating lesions. Compared with EID-CT LBIs, detection was higher for QIR 1-4 at 2.5 mGy and for QIR 2-4 at 1.25 mGy (eg, 0.900 for QIR-4 compared with 0.854 for EID-CT LBIs at 1.25 mGy). Radiation dose reduction potential of PCD-CT with QIR-4 was 54% at 5 mGy compared with VMIs and 39% at 2.5 mGy compared with LBIs., Conclusions: Compared with EID-CT, PCD-CT with QIR substantially improved focal liver lesion detection, especially at low radiation dose. This enables substantial radiation dose reduction while maintaining diagnostic accuracy., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

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., (© 2022 American College of Rheumatology.)

Objective: To assess the reliability and diagnostic accuracy of new radiographic imaging definitions developed by an international multidisciplinary working group for identification of calcium pyrophosphate deposition (CPPD)., Methods: Patients with knee osteoarthritis scheduled for knee replacement were enrolled. Two radiologists and 2 rheumatologists twice assessed radiographic images for presence or absence of CPPD in menisci, hyaline cartilage, tendons, joint capsule, or synovial membrane, using the new definitions. In case of disagreement, a consensus decision was made and considered for the assessment of diagnostic performance. Histologic examination of postsurgical specimens under compensated polarized light microscopy was the reference standard. Prevalence-adjusted bias-adjusted kappa values were used to assess reliability, and diagnostic performance statistics were calculated., Results: Sixty-seven patients were enrolled for the reliability study. The interobserver reliability was substantial in most of the assessed structures when considering all 4 readers (κ range 0.59-0.90), substantial to almost perfect among radiologists (κ range 0.70-0.91), and moderate to almost perfect among rheumatologists (κ range 0.46-0.88). The intraobserver reliability was substantial to almost perfect for all the observers (κ range 0.70-1). Fifty-one patients were included in the accuracy study. Radiography demonstrated an overall specificity of 92% for CPPD, but sensitivity remained low for all sites and for the overall diagnosis (54%)., Conclusion: The new radiographic definitions of CPPD are highly specific against the gold standard of histologic diagnosis. When the described radiographic findings are present, these definitions allow for a definitive diagnosis of CPPD, rather than other calcium-containing crystal depositions; however, a negative radiographic finding does not exclude the diagnosis., (© 2022 The Authors. Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Inertial measurement unit (IMU) sensors are widely used for motion analysis in sports and rehabilitation. The attachment of IMU sensors to predefined body segments and sides (left/right) is complex, time-consuming, and error-prone. Methods for solving the IMU-2-segment (I2S) pairing work properly only for a limited range of gait speeds or require a similar sensor configuration. Our goal was to propose an algorithm that works over a wide range of gait speeds with different sensor configurations while being robust to footwear type and generalizable to pathologic gait patterns. Eight IMU sensors were attached to both feet, shanks, thighs, sacrum, and trunk, and 12 healthy subjects (training dataset) and 22 patients (test dataset) with medial compartment knee osteoarthritis walked at different speeds with/without insole. First, the mean stride time was estimated and IMU signals were scaled. Using a decision tree, the body segment was recognized, followed by the side of the lower limb sensor. The accuracy and precision of the whole algorithm were 99.7% and 99.0%, respectively, for gait speeds ranging from 0.5 to 2.2 m/s. In conclusion, the proposed algorithm was robust to gait speed and footwear type and can be widely used for different sensor configurations.

Background: Acceptance testing and quality assurance (QA) of computed tomography (CT) scans are of great importance to ensure the appropriate performance of the systems. However, current standards and guidelines do not include a dedicated QA program for spectral photon-counting CT (SPCCT), nor adapted tolerance levels., Purpose: To evaluate the technical performance, in terms of image quality and radiation dose, of the first point-of-care SPCCT for the upper extremities (MARS Extremity 5X120, MARS Bioimaging Ltd., Christchurch, New Zealand) and to establish a comprehensive QA program., Methods: The specific dimensions of the scanner with a 125 mm diameter gantry and a small voxel size of 0.1× 0.1 ×0.1 mm 3 require the use of suitable phantoms and evaluation techniques. Indicators such as CT number accuracy, image noise, uniformity, and slice thickness were assessed to characterise the image quality. The in-plane and longitudinal spatial resolutions were evaluated by means of the modulation transfer function (MTF). Noise power spectra (NPS) were calculated to further evaluate the image noise. Material identification capabilities were assessed using clinically relevant high-Z materials (iodine, gold, gadolinium, and calcium). A 100 mm diameter CTDI-like phantom was used to measure the dose indices. A complete radiation survey was carried out to measure the radiation exposure at different points around the scanner., Results: The proposed QA program is based on international and local recommendations as well as practical experience. It includes standardised CT tests and SPCCT-specific methods. Additional methodologies to further assess the system performance are also presented. Tolerance levels are discussed and revised when appropriate. Both in-plane and longitudinal high spatial resolutions were evidenced by the MTF measurements with 1.8 lp·mm -1 and 5.0 lp·mm -1 at 10%, respectively. The calculated effective slice thickness ranged between 0.15 mm and 0.16 mm for the five energy bins and for a reconstructed voxel size of 0.1× 0.1 ×0.1 mm 3 . Reference values of the linear attenuation coefficient of water have been calculated and used to assess the CT number uniformity of water. Evaluation of the CT number accuracy and stability of various clinically relevant materials showed excellent spectral correlation and linearity between HU values and concentrations (r 2 >0.99). The NPS showed less noise correlation between slices than within transverse slice, as well as a systematic increase at low spatial frequencies. The volume CT dose index (CTDI vol ) for a custom-made 100 mm diameter phantom was 9.32 mGy. Radiation measurements around the scanner showed that it is completely shielded except for the access port, and that no additional protective measures are necessary for the patient., Conclusions: A routine QA framework for SPCCT systems has been proposed. Image quality and radiation dose were assessed using newly designed phantoms, relevant metrics, and automated algorithms. Baseline values were established and tolerance levels discussed for the MARS SPCCT scanner based on collected data and international recommendations. This article is protected by copyright. All rights reserved., (This article is protected by copyright. All rights reserved.)