Christine B. Chung

Background: ACLR is associated with altered joint loading and increased risk of post‐traumatic osteoarthritis. Conventional MRI has limited sensitivity to early meniscal differences because of short‐T2 signal decay and magic‐angle effects. Purpose: To evaluate whether 3D ultrashort echo time imaging‐based adiabatic T1rho (UTE‐Adiab‐T1rho) and ultrashort echo time imaging‐based macromolecular fraction (UTE‐MMF) identify regional quantitative MRI differences after ACLR. Study Type: Prospective longitudinal cohort study. Population: 30 control scans, 19 ACLR scans at 6–12 months, and 13 ACLR scans at 12+ months were analyzed. Mean ages were 34.5, 34.5, and 37.2 years; female/male counts were 15/15, 9/10, and 8/5. Field Strength/Sequence: Participants underwent 3‐T knee MRI with 3D fat‐saturated UTE‐Adiab‐T1rho and UTE magnetization transfer sequences. Assessment: UTE‐Adiab‐T1rho and UTE‐MMF maps were generated with single‐component exponential and two‐pool magnetization transfer models. Values were extracted from four meniscal regions of interest by a blinded reader, with blinded redelineation in a subset. Patient‐reported outcomes included International Knee Documentation Committee, Knee Injury and Osteoarthritis Outcome Score, and Western Ontario and McMaster Universities Osteoarthritis Index scores. Statistical Tests: Linear mixed‐effects models accounted for repeated observations. Benjamini‐Hochberg FDR correction was applied. Results: UTE‐Adiab‐T1rho showed significant group ( q = 0.001) and region ( q < 0.001) effects. Compared with controls, UTE‐Adiab‐T1rho was higher in LAM at 6–12 months (+5.60 ms; q = 0.035) and 12+ months (+7.09 ms; q = 0.028), and in LPM at 12+ months (+6.35 ms; q = 0.035). UTE‐MMF showed significant group ( q = 0.041) and region ( q < 0.001) effects. LPM UTE‐MMF was lower than controls at 6–12 months (−3.56 percentage points; q = 0.028) and 12+ months (−3.10 percentage points; q = 0.049). No 6–12 versus 12+ month MRI or PROM contrast survived FDR correction. MRI‐PROM associations were not FDR‐significant (all q ≥ 0.383). Data Conclusion: UTE‐Adiab‐T1rho and UTE‐MMF mapping identified regional MRI differences after ACLR. Pairwise differences were concentrated in lateral regions, but corrected group‐by‐region interactions were not significant. PROMs were worse after ACLR but did not differ between postoperative windows after correction. Evidence Level: 2. Technical Efficacy Stage: 2.

Associations between music participation and language outcomes have been widely reported, yet the extent to which brain structure statistically accounts for these relationships remains unclear, particularly at the population level. Using longitudinal data from the population-based Adolescent Brain Cognitive Development (ABCD) Study, we examined prospective associations between music participation at ages 9–10 and language outcomes two years later and tested whether global cortical morphometry accounted for these associations. The analytic sample included 5,993 children (baseline mean age 10.0 years; 47.1% female), including a twin subsample of 936 participants. Music participation was assessed via parent report of sustained participation, frequency, and intensity. Language outcomes were measured using NIH Toolbox assessments of picture vocabulary, oral reading recognition, and crystallized cognition. Cortical morphometry was quantified across multiple metrics, including global surface area, volume, thickness, and sulcal depth. Longitudinal associations were estimated using linear mixed-effects models, with mediation analyses conducted to quantify the indirect effect of cortical morphometry after adjusting for baseline language performance, sociodemographic factors, and relevant covariates. Sustained music participation was associated with higher crystallized cognition, picture vocabulary, and oral reading recognition scores two years later. Mediation analyses indicated that global cortical surface area and volume, but not cortical thickness or sulcal depth, statistically accounted for a modest proportion of these longitudinal associations (approximately 5–9%). Analyses of practice intensity showed weaker total associations with language outcomes but proportionally greater mediation by surface area and volume, whereas practice frequency exhibited minimal associations and no evidence of mediation. Sensitivity analyses in the twin subsample yielded qualitatively similar patterns, with larger mediated proportions observed for crystallized cognition and picture vocabulary. These findings suggest that global cortical morphometry explains a limited but reproducible component of the longitudinal association between music participation and language outcomes in population-based developmental samples.

Many of the tissues of interest in the evaluation of the knee by magnetic resonance imaging (MRI), including subchondral bone, deep calcified layer of cartilage, menisci, tendons, and ligaments, have very short transverse (T2 and T2*) relaxation times related to their intrinsic structure. These tissues appear anechoic on conventional MRI sequences as signal has already decayed to its minimum when image acquisition begins. Only in the setting of significant injury or degeneration is there detectable signal on conventional MRI sequences. Ultrashort echo time (UTE) MRI, which allows for the qualitative and quantitative assessment of short T2 tissues in their normal states, offers a unique opportunity to detect and intervene upon pathological changes early to prevent irreversible damage. Changes on UTE-T2* imaging allow for the identification of subtle alterations in collagen structure, hydration status, and mineralization of tissues that precede morphologic changes visible on conventional imaging. Early detection of such microstructural changes can allow for the earlier diagnosis of tendinopathy, meniscal injury or degeneration, and early osteoarthritis, potentially allowing for improved patient outcomes through earlier intervention. This review will focus specifically on the clinical applications of one UTE MRI technique, UTE-T2*, in the evaluation of musculoskeletal tissues about the knee.

Trabecular bone architecture has important implications for the mechanical strength of bone. Trabecular elements appear as signal void when imaged utilizing conventional magnetic resonance imaging (MRI) sequences. Ultrashort echo time (UTE) MRI can acquire high signal from trabecular bone, allowing for quantitative evaluation. However, the trabecular morphology is often disturbed in UTE-MRI due to chemical shift artifacts caused by the presence of fat in marrow. This study aimed to evaluate a UTE-MRI technique to estimate the trabecular bone volume fraction (BVTV) without requiring trabecular-level morphological assessment. A total of six cadaveric distal tibial diaphyseal trabecular bone cubes were scanned using a dual-echo UTE Cones sequence (TE = 0.03 and 2.2 ms) on a clinical 3T MRI scanner and on a micro-computed tomography (μCT) scanner. The BVTV was calculated from 10 consecutive slices on both the MR and μCT images. BVTV calculated from the MR images showed strongly significant correlation with the BVTV determined from μCT images (R = 0.84, p < 0.01), suggesting that UTE-MRI is a feasible technique for the assessment of trabecular bone microarchitecture. This would allow for the non-invasive assessment of information regarding bone strength, and UTE-MRI may potentially serve as a novel tool for assessment of fracture risk.

Background: The calcaneal enthesis, an osseous footprint where the Achilles tendon seamlessly integrates with the bone, represents a complex interface crucial for effective force transmission. Bone adapts to mechanical stress and remodels based on the applied internal and external forces. This study explores the relationship between the elasticity of the Achilles tendon enthesis and the bone microstructure in the calcaneal crescent. Methods: In total, 19 calcaneal-enthesis sections, harvested from 10 fresh-frozen human cadaveric foot-ankle specimens (73.8 ± 6.0 years old, seven female), were used in this study. Indentation tests were performed at the enthesis region, and Hayes’ elastic modulus was calculated for each specimen. Micro-CT scanning was performed at 50-micron voxel size to assess trabecular bone microstructure within six regions of interest (ROIs) and the cortical bone thickness along the calcaneal crescent. Results: Significant Spearman correlations were observed between the enthesis elastic modulus and trabecular bone thickness in the distal entheseal (ROI 3) and proximal plantar (ROI 4) regions (R = 0.786 and 0.518, respectively). Conclusion: This study highlights the potential impacts of Achilles tendon enthesis on calcaneal bone microstructure, which was pronounced in the distal calcaneal enthesis, suggesting regional differences in load transfer mechanism that require further investigation.

Objective: To detail the neurovascular crossing patterns between the leash of Henry (LoH) and the deep branch of the radial nerve (DBRN) in supination and pronation of the forearm, using imaging methods with anatomic correlation. Materials and methods: This cross-sectional study was performed ex vivo with HRUS and MRI with anatomic correlation on 6 samples and in vivo with HRUS with Doppler on 55 participants scanned bilaterally. The in vivo participants were enrolled over a 6-month period. The crossing patterns between the LoH and DBRN were assessed ex vivo and in vivo. Additional morphological features of the DBRN, LoH, and fat plane were assessed in vivo only. Biometric features of the participants were recorded. Statistical analyses were performed using Shapiro–Wilk, parametric and non-parametric tests. Results: The most common neurovascular crossing pattern was the ascending branch of the radial recurrent artery (RRAab) crossing below (ex vivo: 83.3%, in vivo: 85.3%) and the muscular branch crossing above (ex vivo: 100%, in vivo: 63.2% %) the DBRN. Both the deep and superficial surfaces of the DBRN exhibited an intimate relationship with the vessels of the LoH. A positive correlation between vessel diameter and anthropometric factors was observed. In addition, the muscular branch exhibited a significantly smaller diameter than the RRAab. Conclusion: Our study detailed the relationship between the LoH and the DBRN and highlighted the high incidence of vessel crossing above the DBRN at the level of the muscular branch. Knowledge of neurovascular crossings is crucial for understanding neurovascular entrapment syndromes and planning interventional procedures to reduce vascular complications.