Teaching diagnostic radiology to radiology majors: Implementation and evaluation of a flipped classroom model.

PURPOSE: Radiology instruction focuses on cultivating medical students' diagnostic thinking skills and practical competence, and lecture-based learning (LBL) is the most commonly used teaching approach. While fact-based, this type of traditional instruction is often non-engaging, leading to a shift toward student-centered models, one of which is the flipped classroom (FC). However, studies involving a comprehensive evaluation of students' experiences using the FC approach and its effects on their learning are lacking. Therefore, this study analyzed the teaching efficacy of the FC approach based on data of large groups of radiology students, accumulated over time. METHODS: Data from 636 medical radiology students taught using the FC and LBL models from 2012 to 2021 were retrospectively collected and analyzed. RESULTS: The test scores of the FC group were significantly higher than those of the LBL group, and improvements in learning initiative and learning ability were notably higher in the FC than in the LBL group. The two groups showed no significant difference in the critical thinking disposition indicator, and the proportion of students with positive critical thinking tendencies was higher in the FC than in the LBL group. The academic and social self-perception scores of the FC group were significantly higher than those of the LBL group, and there was a significant difference in Kolb's learning style. CONCLUSIONS: Based on evidence of completing pre-, in-, and after-class work, the FC approach improved students' academic performance, learning initiative, diagnostic ability, and satisfaction with learning and the teaching institution. Our findings suggest that FC instruction promotes students' assimilation and convergence of learning styles, and cultivates positive critical thinking.

MRI T2 mapping and shear wave elastography for identifying main pain generator in delayed-onset muscle soreness: muscle or fascia?

INTRODUCTION: The main generator of delayed onset muscle soreness (DOMS) is still unknown. This study aimed to clarify the main generator of DOMS. METHODS: Twelve participants performed eccentric exercise (EE) on lower legs. MRI and ultrasound were used to assess changes of calf muscle and deep fascia before and after EE. These results were then compared to the muscle pain level. RESULTS: Compared to baseline, muscle pain peaked at 24-48 h after EE (downstairs 22.25 ± 6.196, 57.917 ± 9.298, F = 291.168, p < 0.01; resting 5.833 ± 1.899, 5.083 ± 2.429, F = 51.678, p < 0.01). Shear wave speed (SWE) of the deep fascia and T2 values of the gastrocnemius muscle and deep fascia all increased and peaked at 48 h after EE (1.960 ± 0.130, F = 22.293; 50.237 ± 2.963, F = 73.172; 66.328 ± 2.968, F = 231.719, respectively, p < 0.01). These measurements were positively correlated with DOMS (downstairs: r = 0.46, 0.76, 0.87, respectively, p < 0.001; resting: r = 0.42, 0.70, 0.77, respectively, p < 0.001). There was a significant positive correlation between SWE and T2 values of deep fascia (r = 0.54, p < 0.01). CONCLUSION: DOMS is a common result of muscle and fascia injuries. Deep fascia edema and stiffness play a crucial role in DOMS, which can be effectively evaluated MR-T2 and SWE. CRITICAL RELEVANCE STATEMENT: Delayed-onset muscle soreness is a common result of muscle and deep fascia injuries, in which the edema and stiffness of the deep fascia play a crucial role. Both MRI and shear wave elastography can be effectively used to evaluate soft tissue injuries. KEY POINTS: • The deep fascia is the major pain generator of delayed-onset muscle soreness. • There is a significant correlation between fascia injury and delayed-onset muscle soreness. • MRI and shear wave elastography are preferred methods for assessing fascia injuries.

Aerobic exercise and metformin on intermuscular adipose tissue (IMAT): insights from multimodal MRI and histological changes in prediabetic rats.

BACKGROUND: Physical exercise is the first-line intervention for prediabetes, and metformin is the most widely used oral insulin-sensitizing agent. Moreover, intermuscular adipose tissue (IMAT) directly affects insulin resistance by helping maintain glucose homeostasis. Here, we evaluated the effects of moderate aerobic exercise and/or metformin on histological IMAT parameters in non-streptozotocin-induced prediabetes. METHODS: Male Wistar rats with prediabetes fed a high-fat diet and high-sugar drinks were randomly assigned to high-fat diet (PRE), metformin (MET), moderate aerobic exercise (EXE), combined therapy (EMC), or EMC + compound-c (EMA) groups for 4 weeks. Multimodal magnetic resonance imaging (MRI) was then performed, and tissue-specific inflammation and energy and lipid metabolism were evaluated in IMAT. RESULTS: The EXE group had lower inflammatory factor levels, lipid metabolism, and mitochondrial oxidative stress, and shorter IMAT adipocyte diameters than the MET group. The MET group exhibited lower IL-1ß and Plin5 expression than the PRE group. Furthermore, the IMAT of the EMC group had lower TNF-α and phosphorylated NF-κB levels and higher GLUT1 and GLUT4 expression than the PRE group. Multimodal MRI revealed significant changes in transverse-relaxation time 2, apparent diffusion coefficient, and fractional anisotropy values in the IMAT and muscles, as well as lower IMAT% values in the EXE and EMC groups than in the MET and PRE groups. CONCLUSION: Moderate aerobic exercise training can effectively improve IMAT function and structure via the AMP-activated protein kinase pathway in prediabetes. Combining metformin with moderate aerobic exercise might elicit modest synergy, and metformin does not counterbalance the beneficial effects of exercise.

Dual-energy CT virtual non-calcium: an accurate method for detection of knee osteoarthritis-related edema-like marrow signal intensity.

OBJECTIVES: To evaluate the performance of a dual-energy computed tomography (DECT) virtual non-calcium (VNCa) technique in the detection of edema-like marrow signal intensity (ELMSI) in patients with knee joint osteoarthritis (OA) compared to magnetic resonance imaging (MRI). METHODS: The study received local ethics board approval, and written informed consent was obtained. DECT and MRI were used to examine 28 knees in 24 patients with OA. VNCa images were generated by dual-energy subtraction of calcium. The knee joint was divided into 15 regions for ELMSI grading, performed independently by two musculoskeletal radiologists, with MRI as the reference standard. We also analyzed CT numbers through receiver operating characteristics and calculated cut-off values. RESULTS: For the qualitative analysis, we obtained CT sensitivity (Readers 1, 2 = 83.7%, 89.8%), specificity (Readers 1, 2 = 99.5%, 99.5%), positive predictive value (Readers 1, 2 = 95.3%, 95.7%), and negative predictive value (Readers 1, 2 = 97.9%, 98.7%) for ELMSI. The interobserver agreement was excellent (κ = 0.92). The area under the curve for Reader 1 and Reader 2 was 0.961 (95% CI 0.93, 0.99) and 0.992 (95% CI 0.98, 1.00), respectively. CT numbers obtained from the VNCa images were significantly different between regions with and without ELMSI (p < .001). CONCLUSIONS: VNCa images have good diagnostic performance for the qualitative and quantitative analysis of knee osteoarthritis-related ELMSI.

Evaluation of the short-term curative effect of closed reduction in the treatment of developmental dysplasia of the hip based on three-dimensional magnetic resonance imaging finite element analysis.

BACKGROUND: Based on the Digital Imaging and Communications in Medicine (DICOM) data of three-dimensional magnetic resonance imaging (3D-MRI), finite element models of the hip joints of children with developmental dysplasia of the hip were established. The primary objectives included simulation and analysis of the finite element model pre- and post-closed reduction under different stances and loads, and evaluation of the size and distribution of von Mises stress in the acetabulum and femoral head pre- and post-operation and the short-term effects. METHODS: Acetabular index measurements of both the unaffected and affected sides were conducted, alongside International Hip Dysplasia Institute (IHDI) classification of the affected hip. Establishing the finite element model of both the affected and unaffected hips was based on the 3D-T1WI sequence DICOM data, using Mimics, 3-matic, and Ansys software, before and after closed reduction surgery. The size and distribution data of von Mises stress on the affected side of the acetabulum and femoral head were collected pre- and post-operation. RESULTS: The study indicated that the increasing acetabular index of the affected hip was directly proportional to the increasing severity based on IHDI classification (P < 0.05). Preoperative IHDI classification significantly correlated with the von Mises stress (r = 0.560-0.569, 0.562-0.564, P < 0.05). Under different stances and load conditions, the von Mises stress on the affected side post-operation was lower than that noted pre-operation (P < 0.01), while that on the acetabulum increased proportionally to the load. Although the magnitude and distribution of von Mises stress on the affected side of the acetabulum were similar to those on the healthy side post-operation, there were statistical differences between the two (P < 0.01). The von Mises stress of the lateral column of the femoral head post-operation was significantly lower than that noted pre-operation (P < 0.01). While the high-stress points of the lateral column disappeared post-operation, the von Mises stress was evenly distributed in the femoral head. CONCLUSIONS: The 3D-MRI finite element could provide the von Mises stress value and distribution characteristics of the acetabulum and femoral head pre- and post-operation. Closed reduction can, therefore, improve the size and distribution of von Mises stress on the affected acetabulum and femoral head.

Intermuscular adipose tissue in Type 2 diabetes mellitus: Non-invasive quantitative imaging and clinical implications.

Intermuscular adipose tissue (IMAT) is an ectopic fat depot found beneath the fascia and within the muscles. IMAT modulates muscle insulin sensitivity and triggers local and systemic chronic low-grade inflammation by producing cytokines and chemokines, which underlie the pathogenesis of Type 2 diabetes mellitus (T2DM). Imaging techniques have been increasingly used to non-invasively quantify IMAT in patients with diabetes in research and healthcare settings. In this study, we systematically reviewed the cell of origin and definition of IMAT, and the use of quantitative and functional imaging technology pertinent to the etiology, risk factors, lifestyle modification, and therapeutic treatment of diabetes. The purpose of this article is to provide important insight into the current understanding of IMAT and future prospects of targeting IMAT for T2DM control.

Assessment of structural brain changes in patients with type 2 diabetes mellitus using the MRI-based brain atrophy and lesion index.

Patients with type 2 diabetes mellitus (T2DM) often have cognitive impairment and structural brain abnormalities. The magnetic resonance imaging (MRI)-based brain atrophy and lesion index can be used to evaluate common brain changes and their correlation with cognitive function, and can therefore also be used to reflect whole-brain structural changes related to T2DM. A total of 136 participants (64 men and 72 women, aged 55-86 years) were recruited for our study between January 2014 and December 2016. All participants underwent MRI and Mini-Mental State Examination assessment (including 42 healthy control, 38 T2DM without cognitive impairment, 26 with cognitive impairment but without T2DM, and 30 T2DM with cognitive impairment participants). The total and sub-category brain atrophy and lesion index scores in patients with T2DM with cognitive impairment were higher than those in healthy controls. Differences in the brain atrophy and lesion index of gray matter lesions and subcortical dilated perivascular spaces were found between non-T2DM patients with cognitive impairment and patients with T2DM and cognitive impairment. After adjusting for age, the brain atrophy and lesion index retained its capacity to identify patients with T2DM with cognitive impairment. These findings suggest that the brain atrophy and lesion index, based on T1-weighted and T2-weighted imaging, is of clinical value for identifying patients with T2DM and cognitive impairment. Gray matter lesions and subcortical dilated perivascular spaces may be potential diagnostic markers of T2DM that is complicated by cognitive impairment. This study was approved by the Medical Ethics Committee of University of South China (approval No. USC20131109003) on November 9, 2013, and was retrospectively registered with the Chinese Clinical Trial Registry (registration No. ChiCTR1900024150) on June 27, 2019.

Intermuscular Fat Content in Young Chinese Men With Newly Diagnosed Type 2 Diabetes: Based on MR mDIXON-Quant Quantitative Technique.

Objective: Skeletal muscle fat content is one of the important contributors to insulin resistance (IR), but its diagnostic value remains unknown, especially in the Chinese population. Therefore, we aimed to analyze differences in skeletal muscle fat content and various functional MRI parameters between diabetic patients and control subjects to evaluate the early indicators of diabetes. In addition, we aimed to investigate the associations among skeletal muscle fat content, magnetic resonance parameters of skeletal muscle function and IR in type 2 diabetic patients and control subjects. Methods: We enrolled 12 patients (age:29-38 years, BMI: 25-28 kg/m2) who were newly diagnosed with type 2 diabetes (intravenous plasma glucose concentration≥11.1mmol/l or fasting blood glucose concentration≥7.0mmol/l) together with 12 control subjects as the control group (age: 26-33 years, BMI: 21-28 kg/m2). Fasting blood samples were collected for the measurement of glucose, insulin, 2-hour postprandial blood glucose (PBG2h), and glycated hemoglobin (HbAlc). The magnetic resonance scan of the lower extremity and abdomen was performed, which can evaluate visceral fat content as well as skeletal muscle metabolism and function through transverse relaxation times (T2), fraction anisotropy (FA) and apparent diffusion coefficient (ADC) values. Results: We found a significant difference in intermuscular fat (IMAT) between the diabetes group and the control group (p<0.05), the ratio of IMAT in thigh muscles of diabetes group was higher than that of control group. In the entire cohort, IMAT was positively correlated with HOMA-IR, HbAlc, T2, and FA, and the T2 value was correlated with HOMA-IR, PBG2h and HbAlc (p<0.05). There were also significant differences in T2 and FA values between the diabetes group and the control group (p<0.05). According to the ROC, assuming 8.85% of IMAT as the cutoff value, the sensitivity and specificity of IMAT were 100% and 83.3%, respectively. Assuming 39.25ms as the cutoff value, the sensitivity and specificity of T2 value were 66.7% and 91.7%, respectively. All the statistical analyses were adjusted for age, BMI and visceral fat content. Conclusion: Deposition of IMAT in skeletal muscles seems to be an important determinant for IR in type 2 diabetes. The skeletal muscle IMAT value greater than 8.85% and the T2 value greater than 39.25ms are suggestive of IR.

Exercise-induced muscle damage: multi-parametric MRI quantitative assessment.

BACKGROUND: To explore the value of magnetic resonance quantitative analysis using diffusion tensor imaging, T2 mapping, and intravoxel incoherent motion in the evaluation of eccentric exercise-induced muscle damage and to compare the effects of various eccentric exercise modes at different time points in rats. METHODS: A total of 174 Sprague-Dawley male rats were randomly divided into five groups: control, once-only exercise, continuous exercise, intermittent exercise, and once-fatigue exercise groups. Each experimental group was divided into seven time-subgroups: 0.5 h, 24 h, 48 h, 72 h, 96 h, 120 h and 168 h after exercise. The quadriceps femoris muscles were then scanned using magnetic resonance imaging. The apparent diffusion coefficient and fractional anisotropy values of diffusion tensor imaging, T2 values of T2 mapping, D and D* values of intravoxel incoherent motion and optical density values of desmin were measured. Associations among different eccentric exercise programmes, magnetic resonance imaging findings, and histopathological results were evaluated. Dunnett's test, two-way repeated measures analysis of variance, and Pearson correlation analysis were used for statistical analysis. RESULTS: Diffusion tensor imaging showed that the number of muscle fibre bundles decreased to varying degrees with different time points and eccentric exercises. Apparent diffusion coefficient values of the exercise groups showed a trend that first increased and then decreased, the opposite of fractional anisotropy. The specimens in all eccentric exercise programmes showed high signal T2 values after exercise, the highest among which was in the once-fatigue exercise group. D and D* in the experimental groups were significantly higher than those in the control group at 0.5-48 h after exercise. The apparent diffusion coefficient, fractional anisotropy, T2, D and D* values correlated with the optical density values of desmin. CONCLUSIONS: Diffusion tensor imaging, T2 mapping, and intravoxel incoherent motion technology accurately reflect the degree of skeletal muscle damage and recovery associated with eccentric exercise. The degree of muscle damage was the lowest in the continuous exercise group and the highest in the once-fatigue exercise group, which may provide more information and guidance for the formulation of physical and athletic training programmes.

Using the Compressed Sensing Technique for Lumbar Vertebrae Imaging: Comparison with Conventional Parallel Imaging.

OBJECTIVE: To compare conventional sensitivity encoding turbo spin-echo (SENSE-TSE) with compressed sensing plus SENSE turbo spin-echo (CS-TSE) in lumbar vertebrae magnetic resonance imaging (MRI). METHODS: This retrospective study of lumbar vertebrae MRI included 600 patients; 300 patients received SENSE-TSE and 300 patients received CS-TSE. The SENSE acceleration factor was 1.4 for T1WI, 1.7 for T2WI, and 1.7 for PDWI. The CS total acceleration factor was 2.4, 3.6, 4.0, and 4.0 for T1WI, T2WI, PDWI sagittal, and T2WI transverse, respectively. The image quality of each MRI sequence was evaluated objectively by the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) and subjectively on a five-point scale. Two radiologists independently reviewed the MRI sequences of the 300 patients receiving CS-TSE, and their diagnostic consistency was evaluated. The degree of intervertebral foraminal stenosis and nerve root compression was assessed using the T1WI sagittal and T2WI transverse images. RESULTS: The scan time was reduced from 7 min 28 s to 4 min 26 s with CS-TSE. The median score of nerve root image quality was 5 (p > 0.05). The diagnostic consistency using CS-TSE images between the two radiologists was high for diagnosing lumbar diseases (κ > 0.75) and for evaluating the degree of lumbar foraminal stenosis and nerve root compression (κ = 0.882). No differences between SENSE-TSE and CS-TSE were observed for sensitivity, specificity, positive predictive value, or negative predictive value. CONCLUSION: CS-TSE has the potential for diagnosing lumbar vertebrae and disc disorders.

Research progress in the pathogenic mechanisms and imaging of severe frostbite.

PURPOSE: This article reviews the pathological mechanisms and progress of imaging of severe frostbite to assist in the search for targets for clinical diagnosis and treatment of severe frostbite. This review also aims to provide strong evidence for clinical diagnosis and treatment of deep frostbite. METHODS: The review was based on the summary and analysis of the existing literature, and explored the pathological mechanism of deep frostbite and the advantages and disadvantages of imaging diagnostic methods. RESULTS: According to the depth of tissue involvement, frostbite is divided into 4 levels. Severe frostbite includes Grade 3 and Grade 4 frostbite. Clinical performance evaluation and imaging diagnostic research have always been the mainstream of severe frostbite diagnosis. Imaging methods focus on vascular patency and tissue vitality. This article introduces angiography, SETCT/CT and MRA, and we summarize the advantages and disadvantages of these imaging methods. We recommend corresponding imaging modalities according to the state of frostbite patients. CONCLUSIONS: Imaging examination, especially angiography and bone scans, provide useful information for determining the diagnosis and prognosis of severe frostbite. In order to obtain a good clinical prognosis, clinicians should first perform SPECT/CT. MRA does not burden the patient's body, but the balance between cost and benefit must be considered. Angiography provides a good feedback on the changes in blood vessel status before and after treatment, which is helpful for discovering the response of limbs to treatment.

Risk Factors for Local Bone Destruction Progression in Palliative Percutaneous Vertebroplasty for Vertebral Metastases and the Significance of Bone Cement Filling Rates.

BACKGROUND: For palliative percutaneous vertebroplasty (PVP) for vertebral metastases, local bone destruction progression (LBDP) commonly occurs in the previously treated vertebrae. There were no studies regarding LBDP and its risk factors in previous reports, and there was no uniform evaluation method for the distribution of bone cement in the vertebrae. OBJECTIVES: We aimed to investigate the risk factors for LBDP after PVP for palliative treatments in patients with vertebral metastases. We also proposed that filling rates could be used as a simple evaluation method to detect vertebral metastases and explored its clinical significance. STUDY DESIGN: This was a retrospective study. SETTING: A university hospital. METHODS: A total of 48 patients and 54 vertebrae that had received PVP as a palliative treatment for vertebral metastases were recruited between October 2012 to October 2019 from the Shengjing Hospital of the China Medical University. We collected and evaluated the data including age, gender, cement filled completely or not, cement dose used, the cement distribution score, time of LBDP, and so on, and the filing rate we proposed was also included. RESULTS: This retrospective study divided 48 patients and 54 vertebrae into group A for those with an LBDP of less than 6 months (n = 41), and group B for those with an LBDP of 6 or more months (n = 13). The complete filling of bone cement and bone cement dose in group B was much higher than that in group A (2.85 ± 0.97 vs. 4.12 ± 1.77; P = 0.027), and the time of recurrent pain in group B was significantly higher compared with that in group A (8.46 ± 2.73 vs. 3.39 ± 1.63; P < 0.0001). There was a statistical difference in the Saliou score and filling rate between the 2 groups (11.77 ± 3.17 vs. 9.34 ± 3.28, P = 0.023; 0.752 ± 0.227 vs. 0.489 ± 0.161, P < 0.0001). Univariate logistic analysis showed that complete filling of cement, the cement dose, Saliou score, and filling rate were statistically significant predictors of LBDP occurring in less than 6 months. Multivariate logistic analysis showed that the filling rate was an independent predictor of patients with vertebral metastases developing LBDP in less than 6 months (odds ratio, < 0.001; 95% confidence interval, < 0.001-0.006; P = 0.0007). The cutoff value for the filling rate calculated from the receiver operating characteristic (ROC) curve analysis was 0.646, which could identify patients who had LBDP in less than 6 months of PVP with a sensitivity of 85.4% and specificity of 84.6%. The 6-month LBDP in the 0.646 or less ROC curve group was higher than that in the greater than 0.646 ROC curve group (97.22% vs. 55.56%, P < 0.0001). LIMITATIONS: The retrospective nature and small sample size were significant. Variation in the time and state of bone cement injected during all PVP procedures was a bias. There was no pathological diagnosis of all vertebral metastases. CONCLUSIONS: The cement dose, complete filling of cement, Saliou score, and filling rate were factors negatively related to LBDP occurring in less than 6 months. Patients with lower filling rates are maybe more likely to have early LBDP compared with those with higher filling rates.

Reliability and Validity of Abdominal Skeletal Muscle Area Measurement Using Magnetic Resonance Imaging.

RATIONALE AND OBJECTIVES: Skeletal muscle mass measurement is the most important element for diagnosing sarcopenia. MRI has an excellent soft-tissue contrast, which can non-invasively assess abdominal skeletal muscle area (SMA) as well as CT. This study aimed to assess the validity and reliability of abdominal SMA measurement by comparing CT and MRI based on the fat image of IDEAL-IQ sequence at the lumbar level mid-L3. MATERIALS AND METHODS: CT and MRI images of 32 patients diagnosed with various kidney diseases were used to analyze intra-observer variability among abdominal SMA measurements. This was done to evaluate the correlation of SMA between CT and fat images of MRI. SMA images were segmented using Materialise Mimics software before quantification. Interobserver reliability and validation of measurements was evaluated by two independent investigators. Abdominal SMA reproducibility and correlation between CT and MRI were then assessed using the intraclass correlation coefficient (ICC), coefficient of variation (CV), Bland-Altman plot, and Pearson's correlation coefficient respectively. RESULTS: The interobserver reliability of MRI was excellent. The CV value was 2.82% while the ICC values ranged between 0.996 and 0.999. Validity was high (CV was 1.7% and ICC ranged between 0.986 and 0.996) for measurements by MRI and CT. Bland Altman analysis revealed an average difference of 2.2% between MRI and CT. The Pearson's correlation coefficient was 0.995 (p < 0.0001). This result revealed that there was a strong correlation between the two technologies. CONCLUSION: MRI exhibited good interobserver reliability and excellent agreement with CT for quantification of abdominal SMA.

Quantitative Evaluation of Hip Muscle Atrophy in Patients with Unilateral Slipped Capital Femoral Epiphysis Based on Magnetic Resonance Imaging.

RATIONALE AND OBJECTIVES: Hip muscle atrophy commonly occurs in patients with unilateral slipped capital femoral epiphysis (SCFE), its effect in patients with unilateral SCFE is worthy of further investigation. This study aimed to investigate the relationship between hip muscle cross-sectional area (M-CSA) and unilateral SCFE using magnetic resonance imaging. MATERIALS AND METHODS: Overall, 32 unilateral SCFE patients (SCFE group) and 15 asymptomatic subjects (control group) were evaluated. All patients underwent magnetic resonance imaging and frog-leg lateral radiograph examinations. M-CSA and Southwick angle were evaluated to calculate the M-CSA ratio of the affected side over the healthy side (A/H) ratio in the SCFE group and the control group. Associations between the A/H ratio, Southwick angle, and the disease time course were investigated with Spearman correlation test. An independent sample t-test, one-way analysis of variance tests, and intraclass correlation coefficients were also applied. RESULTS: A/H ratios of the control group were significantly higher than those of the SCFE group (anterior muscles group: 1.09 ± 0.14 vs 0.86 ± 0.12, medial muscles group: 1.02 ± 0.15 vs 0.82 ± 0.18, posterior muscles group: 1.03 ± 0.07 vs 0.84 ± 0.11, all p < 0.01). A/H ratios of the medial and posterior muscle groups were significantly correlated with severity of SCFE (r = -0.504, p = 0.003, and r = -0.438, p = 0.012, respectively). CONCLUSION: Hip muscle atrophy is associated with SCFE severity in patients with unilateral SCFE. The A/H ratio can reflect the patients' prognosis and rehabilitation status. Maintenance of hip muscle morphology and function may be beneficial to clinical performance and prognosis of patients with unilateral SCFE.

T2 mapping of the acetabular cartilage in infants and children with developmental dysplasia of the hip.

BACKGROUND: T2 mapping is useful for evaluating the cartilage matrix. PURPOSE: To determine the variations in the acetabular cartilage T2 relaxation values between healthy individuals and those with developmental dysplasia of the hip (DDH). MATERIAL AND METHODS: Thirty-three patients with unilateral DDH underwent 3-T magnetic resonance imaging (MRI) between January 2018 and February 2019. Fifteen volunteers (30 hips) were enrolled as controls. T2 values were measured with the T2 mapping sequence in all layers and were equally divided into three layers (deep, middle, and superficial) with equal thickness. We calculated the mean T2 relaxation values for the full thickness, deep, middle, and superficial layers and compared the values between the different groups. In addition, the inter- and intra-observer agreements were calculated. RESULTS: The T2 relaxation values in the DDH arm were significantly lower in the middle, superficial, and full thickness layers compared with those of the volunteers and contralateral hips. The T2 relaxation values of the deep layers showed no significant difference between the different groups. The acetabular cartilage T2 relaxation values increased from the deep layer to the superficial layer in the control and contralateral groups. Both inter- and intra-observer agreements were good. CONCLUSION: MRI T2 mapping may help to diagnose developmental disorders of the acetabular cartilage matrix in infants and children with DDH. Abnormal acetabular cartilage T2 relaxation values may be due to the extraordinary stress load of the femoral head.

Existing contradictions and suggestions: flipped classroom in radiology courses of musculoskeletal disease under Chinese medical educational mode from medical imaging student perspective.

BACKGROUND: Flipped classrooms have already begun to be used in many universities aboard, and they now make up for some of the short comings of the traditional classroom. We introduced the concept of flipped classrooms into a radiology class in China and evaluated the students' performance to find out whether it was a better learning method. Furthermore, we have attempted to identify the problems of application of flipped classrooms (as practiced under the Chinese education system) and make suggestions. METHODS: Facilities made videos and prepared clinical cases and short lectures for the flipped classroom. A total of 55 undergraduate radiology students were asked to finish pre-class learning and pre-learning assessment, participate in a flipped classroom about bone malignant tumours, and complete questionnaires. Teachers were also need to finish the survey. RESULTS: 1) The students showed good performances in the pre-learning assessment. The mean scores for three pre-learning assessment were 89.77, 96.54, and 93.71, respectively; the median scores were 90, 97.5, and 94, respectively. 2) After they attended the flipped classroom, their mastery of knowledge (case-solving skills, basic feature command, comparison ability, and overall knowledge command) showed improvements; after flipped classroom, the scores for these knowledge factors improved to 81.25, 85.42, 85.42, and 85.42%, respectively, compared to the scores they obtained before taking the flipped classroom (1.25, 68.75, 64.58, and 72.92% respectively). 3) The students' discussion time and student-teacher-communication time increased, and the students' questions were solved satisfactorily. 4) CTDI-CV showed no improvement in critical thinking skills after taking the course. 5) The time spent in previewing (pre-class video watching, material reading, and pre-learning assessment) increased significantly. CONCLUSIONS: Flipped classrooms, when tested in a radiology classroom setting, show many advantages, making up for some inadequacies of didactic classrooms. They provide students with better learning experiences. We can continue to practice flipped classroom methods under the curriculum, but we still need to make improvements to make it more suitable for the Chinese medical education mode.

A Longitudinal Study of T2 Mapping Combined With Diffusion Tensor Imaging to Quantitatively Evaluate Tissue Repair of Rat Skeletal Muscle After Frostbite.

Purpose: T2 mapping and diffusion tensor imaging (DTI) enable the detection of changes in the skeletal muscle microenvironment. We assessed T2 relaxation times, DTI metrics, performed histological characterization of frostbite-induced skeletal muscle injury and repair, and provided diagnostic imaging biomarkers. Design and Methods: Thirty-six Sprague Dawley rats (200 ± 10 g) were obtained. Thirty rats were used for establishing a skeletal muscle frostbite model, and six were untreated controls. Functional MR sequences were performed on rats on days 0, 3, 5, 10, and 14 (n = 6 per time point). Rats were then sacrificed to obtain the quadriceps muscles. Tensor eigenvalues (λ1, λ2, and λ3), mean diffusivity (MD), fractional anisotropy (FA), and T2 values were compared between the frostbite model and control rats. ImageJ was used to measure the extracellular area fraction (EAF), muscle fiber cross-sectional area (fCSA), and skeletal muscle tumor necrosis factor α (TNF-α), and Myod1 expression. The correlation between the histological and imaging parameters of the frostbitten skeletal muscle was evaluated. Kolmogorov-Smirnoff test, Leven's test, one-way ANOVA, and Spearman coefficient were used for analysis. Results: T2 relaxation time of frostbitten skeletal muscle was higher at all time points (p < 0.01). T2 relaxation time correlated with EAF, and TNF-α and Myod1 expression (r = 0.42, p < 0.05; r = 0.86, p < 0.01; r = 0.84, p < 0.01). The average tensor metrics (MD, λ1, λ2, and λ3) of skeletal muscle at 3 and 5 days of frostbite increased (p < 0.05), and fCSA correlated with λ1, λ2, and λ3, and MD (r = 0.65, p < 0.01; r = 0.48, p < 0.01; r = 0.52, p < 0.01; r = 0.62, p < 0.01). Conclusion: T2 mapping and DTI imaging detect frostbite-induced skeletal muscle injury early. This combined approach can quantitatively assess skeletal muscle repair and regeneration within 2 weeks of frostbite. Imaging biomarkers for the diagnosis of frostbite were suggested.

MRI Quantitative Analysis of Eccentric Exercise-induced Skeletal Muscle Injury in Rats.

BACKGROUND: The aim of this study was to investigate the value of magnetic resonance (MR) quantitative analysis (MR-T2 mapping technique) for the evaluation of eccentric exercise-induced skeletal muscle injury. MATERIALS AND METHODS: We established an animal model of eccentric exercise-induced damage of Sprague Dawley rat skeletal muscle and evaluated the animals by MR imaging, determined the serum levels of fast skeletal troponin (fsTnI), and examined muscle histopathology, at 0, 1, 2, 4, and 7 days after eccentric exercise. The associations between MR imaging findings, and histopathological and laboratory results were evaluated. RESULTS: T2-weighted images (WIs) of quadriceps femoris muscles showed obvious high signal intensities after exercise, and the T2 values and serum fsTnI levels continued to increase, peaking at day 2 after exercise, p< 0.05. The histopathological findings in muscle specimens, which included swollen and ruptured cells, enlarged extracellular spaces, inflammation, and regeneration of muscle fibers, showed similar trends. After day 2, muscle specimens began to show evidence of self-repair, the T2WI signals decreased in intensity, and the T2 values and serum fsTnI levels decreased; however, at day 7 post injury, the values remained slightly higher than those in the control animals, p< 0.05. The T2 value was significantly correlated with the serum fsTnI level (r = 0.896, p< 0.01). CONCLUSION: T2 mapping technology accurately reflects the histopathological and fsTnI abnormalities and the degree of skeletal muscle damage associated with eccentric exercise followed by recovery. Because T2 mapping technology is noninvasive and can be quantitatively analyzed, it might become the preferred method for performing the diagnosis of eccentric exercise-induced skeletal muscle injury.

Variation of amide proton transfer signal intensity and apparent diffusion coefficient values among phases of the menstrual cycle in the normal uterus: A preliminary study.

PURPOSE: To explore changes in the amide proton transfer (APT) signal intensity (SI) among different phases of the menstrual cycle in healthy young women and to determine whether the APT SI correlates with the apparent diffusion coefficient (ADC). MATERIALS AND METHODS: Twenty healthy women of childbearing age received regular pelvic magnetic resonance imaging (MRI) examinations and APT scans during the menstrual, proliferative and secretory phases of their menstrual cycle. Then, the APT SI and ADC values of the endometrium, myometrium and junctional zone were measured and analyzed to explore the changes during different phases of the menstrual cycle. The Pearson correlation coefficients between the APT SI and ADC were calculated. RESULTS: Besides the APT SI in the secretory phase, the APT SI and ADC in each menstrual phase were higher in the myometrium and endometrium than in the junctional zone, the APT Si did not differ significantly between the endometrium and myometrium during any phase. In each uterine structure, both the SI and ADC were highest in the secretory phase, second highest in the proliferative phase and lowest in the menstrual phase, but the APT SI did not differ significantly between the menstrual phase proliferative phases. Interindividual variation in APT SI and ADC for a given zone or phase ranged from 1.86% to 2.75% and from 0.37 × 10-3 mm2/s to 0.85 × 10-3 mm2/s, respectively. The Pearson correlation coefficient between APT SI and ADC was 0.481 (P < 0.01). CONCLUSION: When the APT SI or ADC values are used to analyze uterine lesions, their changes during the menstrual cycle in childbearing aged women should be considered.