Evaluation of 3-Dimensional Magnetic Resonance Imaging (3D MRI) in Diagnosing Anterior Talofibular Ligament Injury

Development and validation of radiomics model for MRI-based identification of anterior talofibular ligament injuries

Anterior talofibular ligament (ATFL) injuries are common ankle injuries that require accurate grading for effective treatment planning. However, conventional diagnostic methods, including manual MRI interpretation, often lack objectivity and reproducibility. Radiomics, a technique that extracts quantitative features from medical images, offers a promising solution for enhancing diagnostic precision. This study developed a radiomics model based on MRI fat-suppressed proton density-weighted turbo spin-echo images to grade ATFL injuries. A dataset of 467 arthroscopically confirmed cases (276 partial tears, 191 complete tears) was analyzed, and 28 key features were selected for model construction using machine learning classifiers. The support vector machine (SVM) model achieved the best performance, with an AUC of 0.955 (95% CI: 0.931-0.980) on the training set and 0.844 (95% CI: 0.781-0.906) on the validation set. Decision curve analysis and confusion matrix results demonstrated the model's strong predictive accuracy and clinical utility. This SVM-based radiomics model offers a reliable, non-invasive approach for precise ATFL injury diagnosis and grading, with significant potential for improving clinical decision-making and personalized treatment.

Assessment of peroneal tendon lesions using 2-dimensional and 3-dimensional isotropic magnetic resonance imaging with surgical correlation

Accurate diagnoses of peroneal pathologies remains a challenge due to limitations of conventional 2D (dimensional) imaging, which can impact long-term patient outcomes. This study evaluates MRI accuracy and inter-reader reliability of peroneal compartment pathology for 2D and 3D MRI. A consecutive series of patients who underwent peroneal compartment surgery with preoperative 1.5- or 3.0-Tesla ankle MRIs from 2009 to 2024 included 32 scans (22 with 2D, 10 with 2D+3D) from 31 patients (ages 17-74 years, all genders). Three musculoskeletal readers blinded to surgical findings independently analyzed MRI scans for common peroneal tenosynovitis, peroneus brevis and peroneus longus tenosynovitis, tendinopathy, and tears. Inter-reader reliability and diagnostic performance measures were calculated. Using majority vote, overall accuracy, sensitivity, and specificity for peroneal tendons using 2D MRI were 80%, 81%, and 79%, respectively. Using 3D MRI sequences, whether in isolation or combination with 2D MRI, accuracy, sensitivity, and specificity increased to 85%, 88%, and 83%, respectively. The inter-reader reliability for peroneus brevis lesions was 0.45-0.75 for 2D, 0.25-0.35 for 3D, and 0.31-0.54 for combined 2D+3D, while for peroneus longus lesions, it was 0.45-0.90 for 2D, 0.20-0.71 for 3D, and 0.64-0.81 for combined 2D+3D scans. The inter-reader reliability for tenosynovitis ranged from 0.62-0.64 for 2D, 0.25-0.37 for 3D, and 0.57-0.66 for combined 2D+3D scans. The addition of 3D MRI to 2D high-resolution ankle MRI protocol or 3D MRI alone increases accuracy of peroneal compartment lesion detection with minor decrease in inter-reader reliability for peroneal brevis tendon assessment. Larger studies may help validate our findings.

The value of cesarean scar diverticulum in diagnosis of adverse events during dilatation and curettage in patient with cesarean scar pregnancy

OBJECTIVE

The aim of the present study was to explore the relationship between the size of cesarean scar diverticulum (CSD) measured on preoperative magnetic resonance imaging (MRI) and adverse events during dilatation and curettage (D&C) procedure in patients with cesarean scar pregnancy (CSP).

METHODS

The MRI of 197 CSP patients from October 2019 to August 2023 were retrospectively reviewed. The volume, area, and depth of CSD, residual myometrium thickness (RMT), and gestational sac diameter were recorded and tested for correlation with intraoperative estimated blood loss (EBL), and operation time and for any association with the intraoperative adverse events (intraoperative massive hemorrhage [39 cases] and D&C procedure failure [15 cases]). The Spearman test was used to characterize the correlation between the five MRI variables and both the EBL and operation time. The correlation between the five MRI variables and intraoperative adverse events was evaluated with student's t test and Mann-Whitney U test. Diagnostic power of the MRI variables was evaluated by the area under receiver operating characteristic curve (AUC).

RESULTS

The volume, area, and depth of CSD and gestational sac diameter were positively correlated with both EBL and operation time, with the CSD volume having the highest correlation with them (r = 0.543 and 0.461, respectively). Conversely, the RMT displayed a negative correlation with the EBL and operation time. All five MRI variables were significantly associated with both intraoperative massive hemorrhage and D&C failure (all P < 0.001). The CSD volume demonstrated the highest AUC for diagnosing intraoperative massive hemorrhage and D&C failure at 0.893 (95% CI: 0.82-0.92) and 0.901 (95% CI: 0.85-0.94), respectively. The optimal cutoff values for CSD volume in predicting massive hemorrhage and D&C failure were determined to be 5.41 and 8.92 cm3, respectively, with corresponding sensitivities/specificities of 92.31/74.68 and 93.33/82.42, respectively.

CONCLUSION

Quantifying the size of CSD based on preoperative MRI could aid in evaluating risk during D&C in CSP patients, with CSD volume possessing higher diagnostic efficacy than the other four MRI indicators.

Chronic ankle instability: a cadaveric anatomical and 3D high-resolution MRI study for surgical reconstruction procedures

OBJECTIVES

To quantitatively investigate the anatomy of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) for surgical reconstruction procedures in chronic ankle instability (CAI).

METHODS

3D MRI was performed on five fresh-frozen cadaveric ankles using six different spatial resolutions (0.3 × 0.3 × 0.3 mm3, 0.45 × 0.45 × 0.45 mm3, 0.6 × 0.6 × 0.6 mm3, 0.75 × 0.75 × 0.75 mm3, 0.9 × 0.9 × 0.9 mm3, 1.05 × 1.05 × 1.05 mm3). After comparing the MRI results with cadaver dissection, a resolution of 0.45 × 0.45 × 0.45 mm³ was selected for bilateral ankles MRI on 24 volunteers. Classification of the ATFL and four distances of surgically relevant bony landmarkers were analyzed (distance 1 and 3, the fibular origin of the ATFL and CFL to the tip of fibula, respectively; distance 2, the talar insertion of the ATFL to the bare zone of talus; distance 4, the calcaneal insertion of the CFL to the peroneal tubercle).

RESULTS

In subjective evaluation, the interobserver ICC was 0.95 (95% confidence interval (CI): 0.94-0.97) between two readers. The spatial resolution of 0.3 × 0.3 × 0.3 mm3 and 0.45 × 0.45 × 0.45 mm3 received highest subjective score on average and demonstrated highest consistency with autopsy measurements in objective evaluation. Measurements on the 48 volunteer ankles, distance 1 in type I and II were 12.65 ± 2.08 mm, 13.43 ± 2.06 mm (superior-banded in Type II) and 7.69 ± 2.56 mm (inferior-banded in Type II) (means ± SD), respectively. Distance 2 in type I and II were 10.90 ± 2.24 mm, 11.07 ± 2.66 mm (superior-banded in Type II), and 18.44 ± 3.28 mm (inferior-banded in Type II), respectively. Distance 3 and 4 were 4.71 ± 1.04 mm and 14.35 ± 2.22 mm, respectively.

CONCLUSION

We demonstrated the feasibility of quantifying the distances between bony landmarkers for surgical reconstruction surgery in CAI using high-resolution 3D MRI.

CRITICAL RELEVANCE STATEMENT

High-resolution 3D MRI examination may have a guiding effect on the preoperative evaluation of chronic ankle instability patients.

KEY POINTS

Spatial resolutions of 0.3 × 0.3 × 0.3 mm3 and 0.45 × 0.45 × 0.45 mm3 demonstrated highest consistency with autopsy measurements. The spatial resolution of 0.45 × 0.45 × 0.45 mm3 was conformed more to clinical needs. 3D MRI can assist surgeons in developing preoperative plans for chronic ankle instability.

3D isotropic MRI of ankle: review of literature with comparison to 2D MRI

The ankle joint has complex anatomy with different tissue structures and is commonly involved in traumatic injuries. Magnetic resonance imaging (MRI) is the primary imaging modality used to assess the soft tissue structures around the ankle joint including the ligaments, tendons, and articular cartilage. Two-dimensional (2D) fast spin echo/turbo spin echo (FSE/TSE) sequences are routinely used for ankle joint imaging. While the 2D sequences provide a good signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) with high spatial resolution, there are some limitations to their use owing to the thick slices, interslice gaps leading to partial volume effects, limited fluid contrast, and the need to acquire separate images in different orthogonal planes. The 3D MR imaging can overcome these limitations and recent advances have led to technical improvements that enable its widespread clinical use in acceptable time periods. The volume imaging renders the advantage of reconstructing into thin continuous slices with isotropic voxels enabling multiplanar reconstructions that helps in visualizing complex anatomy of the structure of interest throughout their course with improved sharpness, definition of anatomic variants, and fluid conspicuity of lesions and injuries. Recent advances have also reduced the acquisition time of the 3D datasets making it more efficient than 2D sequences. This article reviews the recent technical developments in the domain 3D MRI, compares imaging with 3D versus 2D sequences, and demonstrates the use-case scenarios with interesting cases, and benefits of 3D MRI in evaluating various ankle joint components and their lesions.

Flexed elbow, abducted shoulder, forearm supinated (FABS) reconstruction from three-dimensional elbow MRI: diagnostic performance assessment in biceps head anatomy and pathology

AIM

To determine inter-reader analysis and diagnostic performance on digitally reconstructed virtual flexed, abducted, supinated (FABS) imaging from three-dimensional (3D) isotropic elbow magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Six musculoskeletal radiologists independently evaluated elbow MRI images with virtual FABS reconstructions, blinded to clinical findings and final diagnoses. Each radiologist recorded a binary result as to whether the tendon was intact and if both heads were visible, along with a categorical value to the type of tear and extent of retraction in centimetres where applicable. Kappa and interclass correlation (ICC) were reported with 95% confidence intervals. Areas under the receiver operating curve (AUC) were reported.

RESULTS

FABS reconstructions were obtained successfully in all 48 cases. With respect to tendon intactness, visibility of both heads, and type of tear, the Kappa values were 0.66 (0.53-0.78), 0.24 (0.12-0.37), and 0.55 (0.43-0.66), respectively. For the extent of retraction, the ICC was 0.85 (0.79-0.91) when including the tendons with and without retraction and 0.78 (0.61-0.91) when only including tendons with retraction. For tear versus no tear, AUC values were 0.82 (0.74-0.89) to 0.96 (0.91-1.01).

CONCLUSION

Digital reconstruction of FABS positioning is feasible and allows good assessment of individual tendon head tears and retraction with high diagnostic performance.

Deep Learning Approach for MRI in the Classification of Anterior Talofibular Ligament Injuries

BACKGROUND

Diagnosing anterior talofibular ligament (ATFL) injuries differs among radiologists. Further assessment of ATFL tears is valuable for clinical decision-making.

PURPOSE

To establish a deep learning method for classifying ATFL injuries based on magnetic resonance imaging (MRI).

STUDY TYPE

Retrospective.

POPULATION

One thousand seventy-three patients from a single center with ankle MRI within 1 month of reference standard arthroscopy (in-group dataset), were divided into training, validation, and test sets in a ratio of 8:1:1. Additionally, 167 patients from another center were used as an independent out-group dataset.

FIELD STRENGTH/SEQUENCE

Fat-saturation proton density-weighted fast spin-echo sequence at 1.5/3.0 T.

ASSESSMENT

Patients were divided into normal, strain and degeneration, partial tear and complete tear groups (groups 0-3). The complete tear group was divided into five sub-groups by location and the potential avulsion fracture (groups 3.1-3.5). All images were input into AlexNet, VGG11, Small-Sample-Attention Net (SSA-Net), and SSA-Net + Weight Loss for classification. The results were compared with four radiologists with 5-30 years of experience.

STATISTICAL TESTS

Model performance was evaluated by the receiver operating characteristic (ROC) curve, the area under the ROC curve (AUC), and so on. McNemar's test was used to compare performance among the different models, and between the radiologists and models. The intraclass correlation coefficient (ICC) was used to assess the reliability of the radiologists. P < 0.05 was considered statistically significant.

RESULTS

The average AUC of AlexNet, VGG11, SAA-Net, and SSA-Net + Weight Loss was 0.95, 0.99, 0.99, 0.99 in groups 0-3 and 0.96, 0.99, 0.99, 0.99 in groups 3.1-3.5. The effect of SSA-Net + Weight Loss was similar to SSA-Net but better than AlexNet and VGG11. In the out-group test set, the AUC of SSA-Net + Weight Loss ranged from 0.89 to 0.99. The ICC of radiologists was 0.97-1.00. The effect of SSA-Net + Weight Loss was better than each radiologist in the in-group and out-group test sets.

DATA CONCLUSION

Deep learning has potential to be used for classifying ATFL injuries. SSA-Net + Weight Loss has a better diagnostic effect than radiologists with different experience levels.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY: Stage 2.

The increased anterior talofibular ligament-posterior talofibular ligament angle on MRI may help evaluate chronic ankle instability

PURPOSE

This study intended to compare the difference between the anterior talofibular ligament (ATFL) and posterior talofibular ligament (PTFL) angle with chronic ankle instability (CAI) patients and healthy volunteers, and to confirm whether using the ATFL-PTFL angle could be a reliable assessment method for CAI, so as to improve the accuracy and specificity of clinical diagnosis.

METHODS

This retrospective study included 240 participants: 120 CAI patients and 120 healthy volunteers between 2015 and 2021. The ATFL-PTFL angle of the ankle region was gaged in the cross-sectional supine position on MRI between two groups. After participants undergoing a comprehensive MRI scanning, ATFL-PTFL angles were regarded as the main indicator of patients with the injured ATFLs and healthy volunteers to compare, and were measured by an experienced musculoskeletal radiologist. Moreover, other qualitative and quantitative indicators referring to anatomical and morphological characteristics of the AFTL were included in this study with MRI, such as the length, width, thickness, shape, continuity, and signal intensity of the ATFL, which can be used as secondary indicators.

RESULTS

In the CAI group, the ATFL-PTFL angle was 90.8° ± 5.7°, which was significantly different from the non-CAI group where the ATFL-PTFL angle for 80.0° ± 3.7° (p < 0.001). As for the ATFL-MRI characteristics, the length (p = 0.003), width (p < 0.001), and thickness (p < 0.001) in the CAI group were also significantly different from the non-CAI group. Over 90% of the cases, patients of the CAI group had injured ATFL with an irregular shape, non-continuous, and high or mixed signal intensity.

CONCLUSION

Compared with healthy people, the ATFL-PTFL angle of most CAI patients is larger, which can be used as a secondary index to diagnose CAI. However, the MRI characteristic changes of ATFL may not relate to the increased ATFL-PTFL angle.

Role of the intrinsic subtalar ligaments in subtalar instability and consequences for clinical practice

Subtalar instability (STI) is a disabling complication after an acute lateral ankle sprain and remains a challenging problem. The pathophysiology is difficult to understand. Especially the relative contribution of the intrinsic subtalar ligaments in the stability of the subtalar joint is still controversial. Diagnosis is difficult because of the overlapping clinical signs with talocrural instability and the absence of a reliable diagnostic reference test. This often results in misdiagnosis and inappropriate treatment. Recent research offers new insights in the pathophysiology of subtalar instability and the importance of the intrinsic subtalar ligaments. Recent publications clarify the local anatomical and biomechanical characteristics of the subtalar ligaments. The cervical ligament and interosseous talocalcaneal ligament seem to play an important function in the normal kinematics and stability of the subtalar joint. In addition to the calcaneofibular ligament (CFL), these ligaments seem to have an important role in the pathomechanics of subtalar instability (STI). These new insights have an impact on the approach to STI in clinical practice. Diagnosis of STI can be performed be performed by a step-by-step approach to raise the suspicion to STI. This approach consists of clinical signs, abnormalities of the subtalar ligaments on MRI and intraoperative evaluation. Surgical treatment should address all the aspects of the instability and focus on a restoration of the normal anatomical and biomechanical properties. Besides a low threshold to reconstruct the CFL, a reconstruction of the subtalar ligaments should be considered in complex cases of instability. The purpose of this review is to provide a comprehensive update of the current literature focused on the contribution of the different ligaments in the stability of the subtalar joint. This review aims to introduce the more recent findings in the earlier hypotheses on normal kinesiology, pathophysiology and relation with talocrural instability. The consequences of this improved understanding of pathophysiology on patient identification, treatment and future research are described.