Deep learning reconstruction for turbo spin echo to prospectively accelerate ankle MRI: A multi-reader study.

PURPOSE: To evaluate a deep learning reconstruction for turbo spin echo (DLR-TSE) sequence of ankle magnetic resonance imaging (MRI) in terms of acquisition time, image quality, and lesion detectability by comparing with conventional TSE. METHODS: Between March 2023 and May 2023, patients with an indication for ankle MRI were prospectively enrolled. Each patient underwent a conventional TSE protocol and a prospectively undersampled DLR-TSE protocol. Four experienced radiologists independently assessed image quality using a 5-point scale and reviewed structural abnormalities. Image quality assessment included overall image quality, differentiation of anatomic details, diagnostic confidence, artifacts, and noise. Interchangeability analysis was performed to evaluate the equivalence of DLR-TSE relative to conventional TSE for detection of structural pathologies. RESULTS: In total, 56 patients were included (mean age, 32.6 ± 10.6 years; 35 men). The DLR-TSE (233 s) protocol enabled a 57.4 % reduction in total acquisition time, compared with the conventional TSE protocol (547 s). DLR-TSE images had superior overall image quality, fewer artifacts, and less noise (all P < 0.05), compared with conventional TSE images, according to mean ratings by the four readers. Differentiation of anatomic details, diagnostic confidence, and assessments of structural abnormalities showed no differences between the two techniques (P > 0.05). Furthermore, DLR-TSE demonstrated diagnostic equivalence with conventional TSE, based on interchangeability analysis involving all analyzed structural abnormalities. CONCLUSION: DLR can prospectively accelerate conventional TSE to a level comparable with a 4-minute comprehensive examination of the ankle, while providing superior image quality and similar lesion detectability in clinical practice.

Evaluation of Open Versus Arthroscopic Anterior Talofibular Ligament Reconstruction for Chronic Lateral Ankle Instability With Talar and Subtalar Cartilage MRI T2 Mapping: A 3-Year Prospective Study.

BACKGROUND: Previous studies have examined patients with chronic lateral ankle instability (CLAI) undergoing open and arthroscopic anterior talofibular ligament (ATFL) reconstruction, reporting equivalent clinical results between the 2 procedures. However, data on the magnetic resonance imaging (MRI) outcomes on cartilage health after the 2 procedures are limited. PURPOSE: To compare the cartilage MRI T2 values of the talar and subtalar joints between patients with CLAI undergoing open and arthroscopic ATFL reconstruction. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A prospective study was conducted on patients who underwent open or arthroscopic ATFL reconstruction between January 2018 and December 2019, with a mean follow-up duration of 3 years. MRI scans and American Orthopaedic Foot & Ankle Society (AOFAS) and Tegner score estimations were completed by patients ≤1 week before surgery, as a baseline measurement, and at a 3-year follow-up. A total of 21 healthy volunteers were included who underwent MRI at baseline. Cartilage health was evaluated using MRI T2 mapping. The talar and subtalar cartilage regions were segmented into 14 subregions. RESULTS: At baseline, patients with CLAI had substantially higher T2 values in the medial anterior, medial center, medial posterior, and lateral center regions on the talus compared with the healthy controls (P = .009, .003, .001, and .025, respectively). Remarkable increases in T2 values in the lateral posterior region on the talus were observed from baseline to follow-up in the open group (P = .007). Furthermore, T2 values were considerably higher in the medial center, medial posterior, lateral posterior, and lateral posterior calcaneal facets of the posterior subtalar joint at follow-up in the arthroscopic group compared with the baseline values (P = .025, .002, .006, and .044, respectively). No obvious differences in ΔT2 values were noted between the 2 groups at follow-up. The AOFAS and Tegner scores remarkably improved from baseline to follow-up for the 2 groups (open: 3.25 ± 0.58 vs 5.13 ± 0.81, P < .001; arthroscopic: 3.11 ± 0.90 vs 5.11 ± 1.08, P < .001), with no considerable difference between them. CONCLUSION: The elevated T2 values of cartilage could not be fully recovered after open or arthroscopic ATFL reconstruction. Both arthroscopic and open ATFL reconstruction displayed similar effects on cartilage health concerning ΔT2, but the arthroscopic group demonstrated more degenerative cartilage subregions than the open group.

More severe supraspinatus tendon degeneration on the contralateral shoulders in patients treated for symptomatic rotator cuff tears compared to healthy controls: a quantitative MRI-based study.

BACKGROUND: Patients treated for symptomatic rotator cuff tear (RCT) on one shoulder seem to have a higher prevalence of RCT on the contralateral shoulder. PURPOSE: To compare the supraspinatus (SSP) tendon and RC muscle properties on the contralateral shoulder in patients after repair surgery to those healthy individuals using quantitative magnetic resonance imaging (MRI). MATERIAL AND METHODS: A total of 23 patients treated for RCT (group A) and 23 healthy controls (group B) were recruited. Constant score, visual analog scale score (VAS), and MRI examinations were conducted. The SSP tendon structural status was graded based on the Zlatkin classification and quantified on ultrashort echo time (UTE)-T2* mapping images. Fatty degeneration of RC muscles was classified according to the Goutallier classification and quantified on T2 mapping. RESULTS: The Constant and VAS scores were comparable between groups A and B (all P >0.05). No significant differences were observed in tendon structural status between the two groups (P >0.05). However, significant differences were established in UTE-T2* values of the SSP tendon on the distal subregion between groups A and B (16.4 ± 2.4 ms vs. 14.8 ± 1.2 ms; P = 0.01). Regarding muscle degeneration, no significant differences were displayed in T2 values and Goutallier classification of RC muscles (all P >0.05). CONCLUSION: Patients with a treated RCT demonstrated inferior SSP tendon in the distal subregion on the contralateral shoulders one year postoperatively compared to that of healthy controls based on quantitative MRI data.

Prospective Comparison of Standard and Deep Learning-reconstructed Turbo Spin-Echo MRI of the Shoulder.

Background Deep learning (DL)-based MRI reconstructions can reduce imaging times for turbo spin-echo (TSE) examinations. However, studies that prospectively use DL-based reconstructions of rapidly acquired, undersampled MRI in the shoulder are lacking. Purpose To compare the acquisition time, image quality, and diagnostic confidence of DL-reconstructed TSE (TSEDL) with standard TSE in patients indicated for shoulder MRI. Materials and Methods This prospective single-center study included consecutive adult patients with various shoulder abnormalities who were clinically referred for shoulder MRI between February and March 2023. Each participant underwent standard TSE MRI (proton density- and T1-weighted imaging; conventional TSE sequence was used as reference for comparison), followed by a prospectively undersampled accelerated TSEDL examination. Six musculoskeletal radiologists evaluated images using a four-point Likert scale (1, poor; 4, excellent) for overall image quality, perceived signal-to-noise ratio, sharpness, artifacts, and diagnostic confidence. The frequency of major pathologic features and acquisition times were also compared between the acquisition protocols. The intergroup comparisons were performed using the Wilcoxon signed rank test. Results Overall, 135 shoulders in 133 participants were evaluated (mean age, 47.9 years ± 17.1 [SD]; 73 female participants). The median acquisition time of the TSEDL protocol was lower than that of the standard TSE protocol (288 seconds [IQR, 288-288 seconds] vs 926 seconds [IQR, 926-950 seconds], respectively; P < .001), achieving a 69% lower acquisition time. TSEDL images were given higher scores for overall image quality, perceived signal-to-noise ratio, and artifacts (all P < .001). Similar frequency of pathologic features (P = .48 to > .99), sharpness (P = .06), or diagnostic confidence (P = .05) were noted between images from the two protocols. Conclusion In a clinical setting, TSEDL led to reduced examination time and higher image quality with similar diagnostic confidence compared with standard TSE MRI in the shoulder. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Chang and Chow in this issue.

T2*-corrected Q-Dixon and reduced-FOV diffusion kurtosis imaging (DKI) parameters: correlation with QCT-derived bone mineral density (BMD) and ability to identify abnormal BMD and osteoporosis in postmenopausal women.

Background: Bone marrow fat increases when the bone volume decreases. The composition of the bone marrow microenvironment can also become altered. Assessments of bone marrow fat and bone marrow structural heterogeneity have the potential to predict abnormal bone mineral density (BMD) and osteoporosis. This study aimed to investigate the diagnostic performance of T2*-corrected Q-Dixon and reduced-field-of-view (FOV) diffusion kurtosis imaging (DKI) parameters in determining abnormal BMD and osteoporosis in postmenopausal women. Methods: In this prospective study, the individuals who were eligible for inclusion included postmenopausal women (over 50-year-old) with suspected osteoporosis based on experiencing low back pain. This mono-center study was conducted in tertiary care in China. All of the patients were recruited by using the consecutive sampling method. Subjects who underwent T2*-corrected Q-Dixon and reduced-FOV DKI sequences were enrolled. Fat fraction (FF), T2*, mean kurtosis (MK), and mean diffusivity (MD) values were measured on L1, L2, and L3 vertebral bodies. Quantitative computed tomography (QCT) examinations served as the reference standard. All of the subjects were divided into three groups: normal (BMD >120 mg/cm3), osteopenia (BMD 80-120 mg/cm3), and osteoporosis (BMD <80 mg/cm3). One-way analysis of variance, correlation coefficient analysis, and receiver operating characteristic curve analysis were performed. Results: Among all of the enrolled subjects, 52 were in the normal group, 51 were in the osteopenia group, and 52 were in the osteoporosis group. There were significant differences in FF, T2*, MK, and MD values between the three groups (P<0.001, P<0.001, P<0.001, and P=0.003, respectively). FF, T2*, and MK values exhibited significant negative correlations with BMD values (r=-0.739, P<0.001; r=-0,676, P<0.001; and r=-0.626, P<0.001, respectively). Excellent discriminatory capacity was observed in the Q-Dixon [area under the curve (AUC): 0.976, 95% confidence interval (CI): 0.955-0.997] differentiation between normal and abnormal BMD subjects. It was significantly better than the DKI (AUC: 0.812, 95% CI: 0.741-0.882) parameter combination (P<0.001), whereas the DKI model (AUC: 0.825, 95% CI: 0.739-0.910) performed comparably to the Q-Dixon model (AUC: 0.798, 95% CI: 0.710-0.886) for screening osteoporosis (P=0.57). Conclusions: FF and T2* values measured by using T2*-corrected Q-Dixon, as well as MK and MD values measured by using reduced-FOV DKI, may serve as potential imaging biomarkers in assessing abnormal BMD and osteoporosis in postmenopausal women.

Functional and Structural Outcomes After Arthroscopic Rotator Cuff Repair With or Without Preoperative Corticosteroid Injections.

BACKGROUND: Corticosteroid injections (CSIs) are effective in alleviating pain in patients with rotator cuff tears, but controversy still exists regarding their potential adverse effects on clinical outcomes after rotator cuff repair. PURPOSE: To compare both the functional and the structural outcomes in patients who underwent arthroscopic rotator cuff repair with or without preoperative CSIs. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective cohort study was carried out among patients who underwent arthroscopic rotator cuff repair for partial- and full-thickness tears between 2015 and 2019. The patients who received preoperative CSIs were included in the CSI group and compared with a group without preoperative CSIs (non-CSI group), matched at a ratio of 1:2 based on tear size, age, and follow-up time. Both functional evaluation and structural assessments using magnetic resonance imaging (MRI) were performed at the final follow-up. Clinical outcomes-including retear rate as the primary outcome; pain; functional scores including the Constant-Murley score, American Shoulder and Elbow Surgeons score, and Fudan University Shoulder Score; range of motion (ROM); tendon integrity; tendon healing type; and cartilage thickness-were compared between the 2 groups with a statistical significance of P < .05 and power of 0.9. RESULTS: Thirty-one patients were included in the CSI group, and 62 were included in the non-CSI group. After a mean 3-year follow-up, the 2 groups demonstrated no significant differences in retear rate; visual analog scale for pain; shoulder functional scores; and active ROM including forward flexion, abduction, external rotation, and internal rotation. No significant differences were observed on postoperative MRI scans of the rotator cuff tendon (tendon integrity, healing type, residual tendon attachment area, etc), cartilage thickness, and muscle atrophy. CONCLUSION: No significant differences were found at a mean 3-year follow-up in the retear rates, pain, ROM, and glenohumeral structure on postoperative MRI scans after arthroscopic rotator cuff repair with or without preoperative CSIs.

Quantitative Magnetic Resonance Imaging-Based Tendon Healing of Different Regions of the Shoulder: Comparison Between the Suture-Bridge and Single-Row Techniques.

Background: Rotator cuff retears occur more often at the proximal region with the suture-bridge (SB) technique than at the typical footprint region with the single-row (SR) technique. Few longitudinal clinical trials have focused on the postoperative tendon quality of the repaired rotator cuff at different regions between the 2 techniques. Purpose: To compare tendon healing of the proximal and distal regions between the SB and SR techniques. Study Design: Cohort study; Level of evidence, 3. Methods: Included were consecutive patients who underwent arthroscopic rotator cuff repair and undertook clinical and magnetic resonance imaging (MRI) examinations at 3, 6, and 12 months postoperatively between 2016 and 2017. These patients were divided into the SB and SR groups according to the technique used. The repaired tendon was segmented into distal and proximal regions on ultrashort echo time-T2* mapping images. Clinical outcomes (Constant score, American Shoulder and Elbow Surgeons score, Fudan University Shoulder Score, and visual analog scale for pain) and MRI-based tendon healing (T2* values) of different regions were compared between the 2 groups. The differences in T2* values and clinical scores were determined by 1-way analysis of variance for repeated measurements. Results: A total of 31 patients (17 in SB group and 14 in SR group) were included. At 12-month follow-up, significant improvements from preoperatively were achieved for all patients in all clinical scores (P < .001 for all). No significant between-group differences were found in T2* values of the distal region at any time point; however, the mean T2* value of the proximal region at 3 months was significantly higher in the SB group compared with the SR group (P = .03). This difference became nonsignificant at subsequent follow-up time points. Conclusion: Significant clinical improvements over time can be expected in the first year after arthroscopic rotator cuff repair. In the early postoperative period, higher T2* values in the proximal region of the repaired tendon (representing inferior tendon quality) were seen with the SB technique compared with the SR technique; however, this phenomenon was resolved over time.

Whole-tumor histogram analysis of diffusion-weighted imaging and dynamic contrast-enhanced MRI for soft tissue sarcoma: correlation with HIF-1alpha expression.

OBJECTIVE: To investigate the correlation of histogram metrics from diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters with HIF-1alpha expression in soft tissue sarcoma (STS). METHODS: We enrolled 71 patients with STS who underwent 3.0-T MRI, including conventional MRI, DWI, and DCE-MRI sequences. Location, maximum tumor diameter, envelope, T2-weighted tumor heterogeneity, peritumoral edema, peritumoral enhancement, necrosis, tail-like pattern, bone invasion, and vessel/nerve invasion and/or encasement were determined using conventional MRI images. The whole-tumor histogram metrics were calculated on the apparent diffusion coefficient (ADC), Ktrans, Kep, and Ve maps. Independent-samples t test and one-way ANOVA were used for testing the differences between normally distributed categorical data with HIF-1alpha expression. Pearson and Spearman correlations and multiple linear regression analyses were performed to determine the correlations between histogram metrics and HIF-1alpha expression. Survival curves were plotted using the Kaplan-Meier method. RESULTS: Regarding conventional MRI features, only highly heterogeneous on T2-weighted images (55.6 ± 19.9% vs. 45.4 ± 20.5%, p = 0.041) and more than 50% necrotic area (57.3 ± 20.4% vs. 43.9 ± 19.7%, p = 0.002) were prone to indicate STS with higher HIF-1alpha expression. Histogram metrics obtained from ADC (mean, median, 10th, and 25th percentile values), Ktrans (mean, median, 75th, and 90th percentile values), and Kep (90th percentile values) were significantly correlated with HIF-1alpha expression. Multiple linear regression analysis demonstrated that more than 50% necrosis, ADCskewness, Ktrans90th, and grade III were independently associated with HIF-1alpha expression. CONCLUSION: DWI and DCE-MRI histogram parameters were significantly correlated with HIF-1alpha expression in STS. KEY POINTS: • DWI and DCE-MRI histogram parameters are correlated with HIF-1alpha expression in STS. • More than 50% necrosis, ADCskewness, Ktrans90th, and grade III were independently associated with HIF-1alpha expression in STS.

Using Radiomics to Detect Subtle Architecture Changes of Cartilage and Subchondral Bone in Chronic Lateral Ankle Instability Patients Based on MRI PD-FS Images.

RATIONALE AND OBJECTIVES: To use radiomics to detect the subtle changes of cartilage and subchondral bone in chronic lateral ankle instability (CLAI) patients based on MRI PD-FS images. MATERIALS AND METHODS: A total of 215 CLAI patients and 186 healthy controls were included and randomly split into a training set (n=281, patients/controls=151/130) and an independent test set (n=120, patients/controls=64/56). They underwent ankle MRI examinations. On sagittal PD-FS images, eight cartilage regions and their corresponding subchondral bone regions were drawn. Radiomics models of cartilage, subchondral bone and combined cartilage and subchondral bone were built to differentiate CLAI patients from controls. A receiver operating characteristic curve (ROC) was used to assess the model's performance. RESULTS: In the test dataset, the cartilage model yielded an area under the curve (AUC) of 0.0.912 (95% confidence interval (CI): 0.858-0.965, p<0.001), a sensitivity of 0.859, a specificity of 0.893, a negative predictive value (NPV) of 0.848, and a positive predictive value (PPV) of 0.902. The subchondral bone model yielded an AUC of 0.837 (95% CI: 0.766-0.907, p<0.001), a sensitivity of 0.875, a specificity of 0.714, an NPV of 0.833, and a PPV of 0.778. For the combined model, the AUC was 0.921 (95% CI: 0.863-0.972, p<0.001), sensitivity was 0.844, specificity was 0.911, NPV was 0.836, and PPV was 0.915, whose AUC was higher than those of both the cartilage model and the subchondral bone model. CONCLUSION: The combined radiomics model achieved satisfying performance in detecting potential early architectural changes in cartilage and subchondral bone for CLAI patients.

Knee Cartilage Change within 5 Years after Aclr Using Hamstring Tendons with Preserved Tibial-Insertion: A Prospective Randomized Controlled Study Based on Magnetic Resonance Imaging.

Background: Comparing to anterior cruciate ligament reconstructions (ACLR) with free hamstring tendon (FHT), ACLR with preserved tibial-insertion hamstring tendon (HT-PTI) could ensure the blood supply of the graft and avoid graft necrosis. Yet, whether HT-PTI could protect the cartilage and clinical outcomes in mid-long period after ACLR was still unclear. Purpose: To compare the cartilage change and clinical results between the HT-PTI and FHT in 5 years after ACLR. Study design: Randomized controlled trial; Level of evidence, 2. Methods: A total of 45 patients who underwent isolated ACLR with the autograft of hamstring tendons were enrolled and randomized into 2 groups. The study group undertook ACLR with HT-PTI, whereas the control group had FHT. At pre-operation, and 6, 12, 24, and 60 months post-operation, all cases underwent evaluation with Knee Injury and Osteoarthritis Outcome Score (KOOS), and MR examination. The knee cartilage was divided into 8 sub-regions of which the T2 value and cartilage volume on MRI were measured and documented. The data of two groups were compared and their correlations were analyzed. Results: A total of 18 patients in the HT-PTI group and 19 patients in the FHT group completed the follow-up. The KOOS scores were improved at each follow-up time point (p < 0.001), reached the most superior at 12 months and maintained until 60 months but had no significant difference between the two groups. At 60 months, the cartilage in most subregions in FHT group had higher T2 values than those of pre-operation (p < 0.05) and also higher than HT-PTI group; The cartilage volume changes (CV%) are positive at 6 months and negative from 12 to 60 months in the FHT group, while being negative at all time points in the HT-PTI group. The values of absolute CV% in most subregions in FHT group were significantly higher than those in the HT-PTI group at 6 and 60 months (p < 0.05). Conclusion: The improvement of KOOS score peaked at 12 months in all cases and had no difference between the two groups. The cartilage in the FHT group had more volume loss, earlier and wider damage than that in the HT-PTI group within 5 years. No significant correlation was found among KOOS score, CV%, and T2 value.

Soft tissue sarcoma: correlation of dynamic contrast-enhanced magnetic resonance imaging features with HIF-1α expression and patient outcomes.

Background: To investigate the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) features for predicting hypoxia-inducible factor 1-alpha (HIF-1α) expression and patient outcomes in soft tissue sarcoma (STS). Methods: We enrolled 71 patients with STS who underwent 3.0 Tesla (3.0T) MRI, including conventional MRI and DCE-MRI sequencing. The location, maximum tumor diameter, envelope, T2-weighted tumor heterogeneity, peritumoral edema, peritumoral enhancement, necrosis, configuration, tail-like pattern, bone invasion, and vessel/nerve invasion and/or encasement of the STSs were determined using conventional MRI images. The DCE-MRI parameters, including the volume transfer constant (Ktrans ), reflux rate (Kep ), volume fraction of extravascular extracellular matrix (Ve ), and time-signal intensity curve (TIC) type, of each lesion were independently analyzed by two observers. Independent samples t-test, chi-square test, and Mann-Whitney U-test were performed to evaluate the differences in the MRI features between the two groups. The relationships between the DCE-MRI parameters and HIF-1α expression were analyzed using Spearman's correlation analysis. The Cox proportional hazards model and Kaplan-Meier method were used for survival analysis. Results: Of the conventional MRI features, high heterogeneity, peritumoral enhancement, necrosis, and multilobulation of the T2-weighted tumor were prone to occur in the high-expression group. Of the DCE-MRI parameters, the high-expression group showed significantly higher Ktrans (0.311±0.091 vs. 0.210±0.058 min-1), and Kep values (0.896±0.656 vs. 0.444±0.300 min-1) than the low-expression group. No significant differences in TIC types and Ve values were observed between the low- and high-expression groups (P>0.05). There were positive correlations between Ktrans and Kep values with HIF-1α expression (r=0.705, P<0.001; r=0.123, P<0.001, respectively). Receiver operating characteristic (ROC) analysis indicated high specificity (93.9%) of the Ktrans value for predicting high expression of HIF-1α. The Kep value provided the best performance in diagnostic sensitivity (84.2%). Survival analyses revealed that more than 50% necrosis, multilobulation, and Ktrans values greater than 0.262 min-1 were strongly associated with a higher risk of death. Conclusions: Conventional MRI features and DCE-MRI parameters were significantly helpful in determining HIF-1α expression levels and predicting the overall survival (OS) of patients with STS.

Relationship between oseteoporosis with fatty infiltration of paraspinal muscles based on QCT examination.

INTRODUCTION: To investigate the correlation between paraspinal muscles features and osteoporosis in lumbar spine. MATERIALS AND METHODS: A total of 367 subjects who underwent quantitative computed tomography (QCT) examination were enrolled in this study. QCT pro workstation was used to obtain the mean bone mineral density (BMD) of the lower lumbar spine. Fat fraction (FF) and cross-section area (CSA) of the paraspinal muscles at the corresponding levels were measured. All participants were divided into normal, osteopenia, and osteoporosis groups. One-way ANOVA and independent samples t tests were performed to compare differences between groups. Pearson and Spearman correlation coefficients and partial correlation analysis after controlling for confounding factors were used to analyze the correlation between BMD and paraspinal muscles measurements. RESULTS: Among the 367 participants included, 116 were in the normal group, 130 in the osteopenia group and 121 in the osteoporosis group. There were significant differences among the three groups for the mean and multifidus FF. BMD showed negative correlations with the FF of the paraspinal muscles. Multifidus and mean FF showed the best correlation (r = - 0.654, - 0.777). There were also significant differences in the mean and multifidus FF between different age groups, while after controlling for confounding factors, there was no correlation between age and FF of the paraspinal muscles. CONCLUSION: This preliminary study demonstrated the association of BMD with fatty infiltration of paraspinal muscles. Different muscles might have specific effects in different sex and age groups.

Identification of abnormal BMD and osteoporosis in postmenopausal women with T2*-corrected Q-Dixon and reduced-FOV IVIM: correlation with QCT.

OBJECTIVE: To investigate the predictive value of quantitative Dixon (Q-Dixon) and intravoxel incoherent motion (IVIM) parameters in identifying normal bone mineral density (BMD), osteopenia, and osteoporosis in postmenopausal women. METHODS: We enrolled 105 postmenopausal female subjects who underwent 3 T MRI, including T2*-corrected Q-Dixon and reduced-field-of-view (reduced-FOV) IVIM sequences. The measurement of Q-Dixon and IVIM parameters was performed on the L3 vertebral body. BMD values were obtained using quantitative computed tomography (QCT) examination, which served as the reference standard. The intraclass correlation coefficient (ICC) was used to assess the measurement reproducibility across observers. One-way ANOVA, Spearman analysis, and receiver operating characteristic curve analysis were performed. RESULTS: There were significant differences in FF, T2*, and Dslow values between the three groups (p = 0.011, p = 0.021, p = 0.015). FF and T2* values were negatively correlated with BMD (r = - 0.747, p < 0.001; r = - 0.498, p = 0.007). Dslow and f values were positively correlated with BMD (r = 0.659, p < 0.001; r = 0.472, p = 0.012). Dslow values showed a significant negative correlation with FF values (r = 0.659, p < 0.001). f values showed a moderate negative correlation with FF values (r = - 0.387, p = 0.026). The sensitivity (89.2%), specificity (92.7%), and accuracy (91.4%) of the Q-Dixon model in differentiating normal and abnormal BMD (osteopenia and osteoporosis) were superior to those of the IVIM model. Conversely, the IVIM model outperformed the Q-Dixon model in discriminating osteopenia and osteoporosis; the sensitivity, specificity, and accuracy were 85.4%, 81.5%, and 83.8%, respectively. CONCLUSIONS: T2*-corrected Q-Dixon and reduced-FOV IVIM parameters have the potential to become new biomarkers in the assessment of abnormal BMD and osteoporosis in postmenopausal women. KEY POINTS: • T2*-corrected Q-Dixon and reduced-FOV IVIM parameters are correlated with BMD. • Fat quantification and bone trabecular microstructure information provided by T2*-corrected Q-Dixon outperforms reduced-FOV IVIM in identifying abnormal BMD. • Quantification of bone marrow water molecule diffusion movement and perfusion effects obtained from the reduced-FOV IVIM technique can differentiate osteopenia and osteoporosis more accurately than T2*-corrected Q-Dixon.

Correlation Between Bone Mineral Density (BMD) and Paraspinal Muscle Fat Infiltration Based on QCT: A Cross-Sectional Study.

To investigate the correlation between fatty infiltration of the paraspinal muscle and bone mineral density (BMD). In total, 367 subjects (182 men and 185 women) who underwent quantitative computed tomography (QCT) examination were enrolled in this study. A QCT Pro workstation was used to obtain the mean BMD of the lower lumbar spine (L3, L4, L5) and fat fraction (FF) of the paraspinal muscle (psoas and erector spinae) at the corresponding levels. The patient's age, sex, body mass index, number of previous vertebral fractures, physical activity level, and visual analog scale (VAS) score for lower back pain were recorded. For categorical variables, one-way ANOVA and independent-samples t tests were performed. Spearman and Pearson correlation coefficients were used to analyze the correlations among continuous variables. Influential factors were analyzed by multivariate linear regression analysis. Regarding the mean paraspinal muscle FF, there were significant differences between the different vertebral fracture groups (P < 0.05). Age and VAS score showed a positive correlation with the mean paraspinal muscle FF (r = 0.389, 0.454). BMD showed a negative correlation with the mean paraspinal muscle FF (r = - 0.721). The multiple linear regression analysis showed that vertebral fracture (ß = 0.851, P = 0.021) and BMD (ß = - 4.341, P = 0.004) were independent factors of the mean paraspinal muscle FF. This study demonstrated that an advanced age, a greater VAS score, a higher number of vertebral fractures, and a lower BMD may be associated with more severe fatty infiltration of the paraspinal muscle.

Q-Dixon and GRAPPATINI T2 Mapping Parameters: A Whole Spinal Assessment of the Relationship Between Osteoporosis and Intervertebral Disc Degeneration.

BACKGROUND: The relationship between osteoporosis and intervertebral disc (IVD) degeneration remains controversial. Novel quantitative Dixon (Q-Dixon) and GRAPPATINI T2 mapping techniques have shown potential for evaluating the biochemical components of the spine. PURPOSE: To investigate the correlation of osteoporosis with IVD degeneration in postmenopausal women. STUDY TYPE: Prospective. SUBJECTS: A total of 105 postmenopausal females (mean age, 65 years; mean body mass index, 26 kg/m2 ). FIELD STRENGTH/SEQUENCE: 3 T; sagittal; 6-echo Q-Dixon, multiecho spin-echo GRAPPATINI T2 mapping, turbo spin echo (TSE) T1-weighted and TSE T2-weighted sequences. ASSESSMENT: The subjects were divided into normal (N = 47), osteopenia (N = 28), and osteoporosis (N = 30) groups according to quantitative computed tomography examination. The Pfirrmann grade of each IVD was obtained. Region of interest analysis was performed separately by two radiologists (X.L., with 10 years of experience, and S.C., with 20 years of experience) on a fat fraction map and T2 map to calculate the bone marrow fat fraction (BMFF) from the L1 to L5 vertebrae and the T2 values of each adjacent IVD separately. STATISTICAL TESTS: One-way analysis of variance, post-hoc comparisons, and Kruskal-Wallis H tests were performed to evaluate the differences in the magnetic resonance imaging parameters between the groups. The relationships between BMFF and the IVD features were analyzed using the Spearman correlation analysis and linear regression models. RESULTS: There were significant differences in BMFF among the three groups. The osteoporosis group had higher BMFF values (64.5 ± 5.9%). No significant correlation was found between BMFF and Pfirrmann grade (r = 0.251, P = 0.06). BMFF was significantly negatively correlated with the T2 of the adjacent IVD from L1 to L3 (r = -0.731; r = -0.637; r = -0.547), while significant weak correlations were found at the L4 to L5 levels (r = -0.337; r = -0.278). DATA CONCLUSION: This study demonstrated that osteoporosis is associated with IVD degeneration. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 4.

Learning From Highly Confident Samples for Automatic Knee Osteoarthritis Severity Assessment: Data From the Osteoarthritis Initiative.

Knee osteoarthritis (OA) is a chronic disease that considerably reduces patients' quality of life. Preventive therapies require early detection and lifetime monitoring of OA progression. In the clinical environment, the severity of OA is classified by the Kellgren and Lawrence (KL) grading system, ranging from KL-0 to KL-4. Recently, deep learning methods were applied to OA severity assessment to improve accuracy and efficiency. However, this task is still challenging due to the ambiguity between adjacent grades, especially in early-stage OA. Low confident samples, which are less representative than the typical ones, undermine the training process. Targeting the uncertainty in the OA dataset, we propose a novel learning scheme that dynamically separates the data into two sets according to their reliability. Besides, we design a hybrid loss function to help CNN learn from the two sets accordingly. With the proposed approach, we emphasize the typical samples and control the impacts of low confident cases. Experiments are conducted in a five-fold manner on five-class task and early-stage OA task. Our method achieves a mean accuracy of 70.13% on the five-class OA assessment task, which outperforms all other state-of-art methods. Despite early-stage OA detection still benefiting from the human intervention of lesion region selection, our approach achieves superior performance on the KL-0 vs. KL-2 task. Moreover, we design an experiment to validate large-scale automatic data refining during training. The result verifies the ability to characterize low confidence samples. The dataset used in this paper was obtained from the Osteoarthritis Initiative.

Radiomics Feature Analysis of Cartilage and Subchondral Bone in Differentiating Knees Predisposed to Posttraumatic Osteoarthritis after Anterior Cruciate Ligament Reconstruction from Healthy Knees.

OBJECTIVES: To introduce a new implementation of radiomics analysis for cartilage and subchondral bone of the knee and to compare the performance of the proposed models to classic T2 relaxation time in distinguishing knees predisposed to posttraumatic osteoarthritis (PTOA) after anterior cruciate ligament reconstruction (ACLR) and healthy controls. METHODS: 114 patients following ACLR after at least 2 years and 43 healthy controls were reviewed and allocated to training (n = 110) and testing (n = 47) cohorts. Radiomics models are built for cartilage and subchondral bone regions of different compartments: lateral femur (LF), lateral tibia (LT), medial femur (MF), and medial tibia (MT) and combined models of four compartments on T2 mapping images. The model performance of discrimination between patients and controls was illustrated with the receiver operating characteristic curve and compared with a classic T2 value-based model. RESULTS: The T2 value model of cartilage yielded moderate predictive performance in discerning patients and controls, with an AUC of 0.731 (95% confidence interval, 0.556-0.875) in the testing cohort, while the radiomics signature of cartilage and subchondral bone of different compartments demonstrated excellent performance, with AUCs of 0.864-0.979. Furthermore, the combined model reported an even better performance, with AUCs of 0.977 (95% confidence interval, 0.919-1.000) for the cartilage and 0.934 (95% confidence interval, 0.865-0.994) for the subchondral bone in the testing cohort. CONCLUSION: The radiomics features of the cartilage and subchondral bone may be able to provide powerful tools with more sensitive detection than T2 values in differentiating knees at risk for PTOA after ACLR from healthy knees.

Sex-Based Differences in Clinical Outcomes After Arthroscopic Anterior Shoulder Stabilization: Results at 5-Year Follow-up.

BACKGROUND: The influence of patient sex on clinical outcomes after arthroscopic anterior shoulder stabilization is unclear. PURPOSE: To investigate sex-based differences in clinical outcomes after arthroscopic anterior shoulder stabilization. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective study was conducted among 76 patients who underwent arthroscopic anterior shoulder stabilization from February 2010 to December 2017. The patients were grouped by sex. The recurrence rate of instability was compared, as were pre- and postoperative pain scores, functional outcome scores, and active range of motion (ROM). Postoperative magnetic resonance imaging (MRI) was also performed for structural assessment of the glenohumeral joint. RESULTS: No significant difference was found in the recurrence rate between female and male patients (13.3% vs 14.8%; P ≥ .999; risk ratio, 1.107 [95% CI, 0.266-4.597]). Compared with male patients, female patients had a significantly lower preoperative Constant score (94.4 ± 6.4 vs 85.4 ± 11.1; P = .002), forward flexion (173.8° ± 10.7° vs 154.0° ± 33.8°; P = .011), abduction (171.0° ± 18.4° vs 142.7° ± 39.9°; P = .001), and external rotation (76.6° ± 21.6° vs 67.7° ± 20.4°; P = .037). Postoperatively, female patients had a significantly lower Simple Shoulder Test score compared with men (8.8 ± 1.9 vs 10.3 ± 1.6; P = .005). The mean changes from pre- to postoperative Rowe score (43.6 ± 21.4 vs 31.5 ± 19.8; P = .044), Constant score (9.9 ± 8.9 vs 0.8 ± 8.1; P = .002), forward flexion (24.0 ± 36.2 vs 4.2 ± 10.9; P = .013), abduction (36.0 ± 38.3 vs 7.6 ± 18.4; P < .001), and external rotation (19.7 ± 21.3 vs 6.7 ± 26.2; P = .023) in female patients were significantly higher than those in the men. There were no sex-based differences on any MRI parameter measured. CONCLUSION: Female patients had a similar recurrence rate as that of male patients after arthroscopic anterior shoulder stabilization. Most postoperative clinical outcome measures showed no significant difference between the sexes. Despite worse preoperative values, more significant improvements in postoperative shoulder function and active ROM were seen in women.

Enhanced Fenton-like catalytic activity and stability of g-C3N4 nanosheet-wrapped copper phosphide with strong anti-interference ability: Kinetics and mechanistic study.

Metal-based Fenton-like catalysts usually activate H2O2 to produce free radicals (•OH and O2•-) for the degradation of organic pollutants. However, a catalytic reaction dominated by free radicals is easily interfered with by various inorganic anions and water matrices. Herein, g-C3N4-wrapped copper phosphide (CuxP), as a highly efficient Fenton-like catalyst, was successfully synthesized by a simple low-temperature phosphidation method. The CuxP/g-C3N4 catalyst exhibited excellent catalytic ability for the removal of various organic contaminants over a wide pH range of 3-11. In addition, the catalyst exhibited strong anti-interference ability toward various inorganic anions (Cl-, SO42-, NO3-, F-, H2PO4-, HCO3- and CO32-) and water matrices (lake water, river water, tap water and simulated water matrix). The reasons for this performance were analyzed by verifying the mechanism of the catalytic reaction. Compared to the pure CuxP catalyst, the CuxP/g-C3N4 composite possessed good catalytic stability. The enhanced and deactivated mechanisms of the CuxP/g-C3N4 catalyst were systematically analyzed by a series of characterization techniques. A possible reaction mechanism was also proposed based on the experimental results. This work provides new insights into designing highly efficient metal-based Fenton-like catalysts with strong anti-interference ability to practically treat wastewater.