Pediatric Monteggia fracture-dislocations may be overlooked when ulnar injury is incomplete or plastically deformed and radiocapitellar malalignment is subtle. Radiographic interpretation is further complicated by incomplete ossification, non-standard projection, and the limitations of applying a single alignment line across all ages and imaging scenarios. This narrative review synthesizes clinically relevant evidence on radiocapitellar alignment assessment in suspected pediatric Monteggia lesions and proposes an imaging interpretation framework for radiographs and problem-solving imaging. The review integrates developmental anatomy, radiographic adequacy, radiocapitellar line behavior, forearm-based P-line assessment, lateral humeral line assessment, ulnar bow sign, and targeted second-line imaging with ultrasound, MRI, and arthrography. The framework emphasizes three practical steps: first determining whether the available images are adequate for line-based assessment; then selecting the line or sign according to age, ossification stage, projection, and available landmarks; and finally reporting discordant or limited studies as equivocal rather than forcing a binary normal/abnormal interpretation. We also summarize diagnostic error considerations, structured reporting elements, and future directions for AI-assisted measurement and uncertainty-aware interpretation. The proposed framework is intended to support consistent radiologic reasoning and communication among emergency physicians, radiologists, and pediatric orthopedic surgeons. It is not a validated diagnostic rule, and prospective observer-performance studies are needed before implementation as a clinical pathway.

CT has evolved into a complementary tool for three-dimensional (3-D) structural assessment in OA research. This review highlights advances across key domains of CT-based OA imaging: structural features, shape modeling, alignment, contact stress modeling, bone morphometry and BMD, articular cartilage, meniscus, and combination with other modalities. CT's high-resolution bone visualization enables accurate quantification of osteophytes, subchondral bone cysts, and sclerosis, as well as precise measurement of joint space width (JSW). The high geometric fidelity of CT also facilitates 3-D bone shape modeling. Additionally, CT supports dynamic evaluation of joint mechanics, including articular contact stress estimates. Weight-bearing CT enables functional assessment of joint alignment and JSW under physiologic loads. QCT, HR-pQCT, and micro-CT support detailed analysis of periarticular bone morphometry and BMD, capturing microarchitectural changes linked to OA severity. CT arthrography provides high-contrast visualization of articular cartilage and has shown superior sensitivity over MRI for detecting cartilage and meniscal defects. Dual-energy CT enables material differentiation, offering a noninvasive alternative to arthrocentesis. Spectral photon-counting CT combines ultra-high spatial resolution with multi-energy tissue characterization, improving the accuracy of compositional and structural assessment. Moreover, CT provides the anatomical framework for hybrid imaging modalities, such as PET CT and SPECT CT, which can assess bone metabolic activity. Together, these emerging CT modalities allow detailed 3-D analysis of bone geometry and subchondral changes, as well as evaluation of cartilage thickness and meniscal integrity, alongside accurate 3-D alignment measurements. These advances establish CT as a versatile platform for developing OA imaging biomarkers, monitoring disease progression, and enhancing clinical trial outcomes. Insights gained from these technologies will continue to inform future OA research and guide clinical decision-making.

Background and Objectives: This study aimed to assess the association between the aponeurotic expansion of the supraspinatus tendon (AEST) and supraspinatus tendon tears utilizing magnetic resonance (MR) arthrography in an extensive patient cohort and to determine its clinical relevance. Materials and Methods: All MR arthrography images were retrospectively assessed by two radiologists with expertise in arthrography. In both the AEST group and the comparison group consisting entirely of patients with rotator cuff tendon tears, the location and extent of the tear were documented, along with the distance between the tear and the AEST in the study group. In patients with AEST, it was also noted whether the tear extended to or structurally involved the AEST. Results: AEST was identified in 61 (7.4%) of the 827 MR arthrograms. The isolated supraspinatus tendon tear emerged as the most prevalent, representing 33.3% of patients with AEST. The triple combination of tears involving the supraspinatus, subscapularis, and infraspinatus accounted for 25.9% of patients with AEST. AEST tears alone were observed in just 3.3% of cases. The incidence of triple combination tears in patients with AEST was found to be significantly lower at 25.9% compared to 59.3% in the control group without AEST (p = 0.028). Conclusions: In this study, the authors found that the incidence of combined tendon tears in patients with AEST was significantly lower compared to the control group. This result suggests that the AEST likely acts as a structural barrier limiting the anterior progression of rotator cuff tears, particularly toward the subscapularis tendon.

Objectives:Photon-counting detector computed tomography (PCD-CT) enables spectral imaging andK-edge-based material separation. In arthrography, iodine and gadolinium are often co-administered for complementary CT/MR evaluation but cannot be readily separated or quantified with conventional CT or magnetic resonance imaging. We developed a dual-contrast PCD-CT material decomposition approach to simultaneously separate and quantify iodine, gadolinium, and calcium.Approach:Calibration phantoms containing iodine, gadolinium, calcium, and iodine-gadolinium mixtures, as well as anex vivopig-tail specimen, were scanned on a benchtop PCD-CT system. Six energy bins spanning the iodine and gadoliniumK-edges were reconstructed and analyzed using principal component analysis (PCA). Linearity, fit-based quantitative accuracy, and contrast-to-noise ratio (CNR) were evaluated for pure-agent phantoms (1%-5%) and mixed-contrast phantoms (1%-3%).Main results:PCA-based decomposition successfully separated iodine, gadolinium, and calcium. In phantoms containing both pure and mixed contrast, normalized signals showed strong linearity with contrast concentrations, with slopes of 0.94 for iodine and 0.97 for gadolinium (R2=0.989and 0.997, respectively). In calcium-containing mixed phantoms, linearity remained high, with slopes of 0.98 for iodine and 0.93 for gadolinium (R2=0.99for both). The fit-based mean absolute error/root mean square error values were 0.13%/0.16% for pure iodine and 0.04%/0.04% for pure gadolinium. Both contrast agents were detectable at 1% weight/volume and above, with CNR values of 5-8 under the current imaging conditions.Ex vivoscans showed clear separation of bone and injected contrasts.Significance:This pilot study demonstrates the feasibility of PCA-based dual-contrast PCD-CT arthrography for simultaneous imaging of calcium, iodine, and gadolinium. The method provides complementary quantitative information within a dual-contrast workflow and shows promise for musculoskeletal and joint imaging.

Thirty-three panelists from 23 institutions participated in a three-round Delphi consensus process to establish interdisciplinary guidelines for reporting knee MRI findings on 11 meniscus topics: MRI criteria for tears, possible tears, tear patterns, tear descriptors, intrameniscal descriptors, meniscal roots, posteromedial meniscocapsular junction, meniscus extrusion, assessment of the postoperative meniscus, retear descriptors, and ancillary findings. All panelists completed all Delphi rounds. In round 1, 350 free-text entries (mean, 31.8 entries per topic ± 2.2 [SD]) were submitted. In round 2, 32 statements (mean, 2.9 entries per topic ± 1.6) were collected from 11 teams (one orthopedic surgeon and two musculoskeletal radiologists per team), with 75% (24 of 32 panelists) achieving consensus using a 9-point Likert scale. Consensus was defined as a score of at least 7 (≥80% of panelists) and a median score of at least 7 (IQR ≤3). In round 3, all statements achieved consensus. Between rounds 2 and 3, agreement significantly increased (P < .05) among all panelists on the topics of possible tears (to express uncertainty) and tear descriptors (for treatment planning), among orthopedic surgeons on MRI criteria for tear and the assessment of the postoperative meniscus (specifically on reporting equivocal findings and the use of MR arthrography), and among radiologists on tear patterns, intrameniscal descriptors, meniscal roots, and retear descriptors.