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Aim and objectives: In forensic age estimation e.g. for judicial proceedings surpassed age thresholds can be legally relevant. To examine age related differences in skeletal development the recommendations by the Study Group on Forensic Age Diagnostics (AGFAD) are based on ionizing radiation (among others orthopantomograms, plain x-rays of the hand). Vieth et al. and Ottow et al. proposed MRI-classifications for the epiphyseal-diaphyseal fusion of the knee joint to define different age groups in healthy volunteers. The aim of the present study was to directly compare these two classifications in a large German patient population. Materials and methods: MRI of the knee joint of 900 patients (405 female, 495 male) from 10 to 28 years of age were retrospectively analyzed. Acquired T1-weighted turbo spin-echo sequence (TSE) and T2-weighted sequence with fat suppression by turbo inversion recovery magnitude (TIRM) were analyzed for the two classifications. The different bony fusion stages of the two classifications were determined and the corresponding chronological ages assigned. Differences between the sexes were analyzed. Intra- and inter-observer agreements were determined using Cohen's kappa. Results: With the classification of Ottow et al. it was possible to determine completion of the 18th and 21st year of life in both sexes. With the classification of Vieth et al. completion of the 18th year of life for female patients and the 14th and 21st year of life in both sexes could be determined. The intra- and inter-observer agreement levels were very good (κ > 0.82). Conclusion: In the large German patient cohort of this study it was possible to determine the 18th year of life with for both sexes with the classification of Ottow et al. and for female patients with the classification of Vieth et al. It was also possible to determine the 21st year of life for all bones with the classification of Ottow et al. and for the distal femur with the classification of Vieth et al. [ABSTRACT FROM AUTHOR]

A disk-shaped meniscus is a commonly known alternative to the C-shaped meniscus, which is defined by a larger-than-normal meniscus body. However, the enlarged meniscus has a severe disadvantage, which is the increase in shearing forces exerted on it, which can lead to a tear in its body. The Wrisberg form of discoid lateral meniscus is a rare abnormality. The absence of the posterior meniscotibial ligament results in an excessive range of movement and instability of the meniscus, with only its meniscofemoral ligament (Wrisberg's ligament) remaining intact and attached to the posterior horn of the meniscus. Additionally, a Wrisberg variant can exhibit a significant disorder in its microstructure due to an abnormal collagen network, mucosal disintegration, and a lack of vascularity. This study includes 32 skeletally immature patients who came to our institution with symptomatic discoid lateral meniscus. The initial evaluation of every knee included magnetic resonance imaging (MRI), followed by arthroscopy. MRI enables the classification of discoid meniscus based on meniscal morphology, stability or instability, meniscal intrasubstance degradation, and the occurrence of meniscal rupture. The discoid meniscus was reshaped, excising the hypertrophied central portion of the meniscus. The International Knee Documentation Committee (IKDC) system, which is an online system for the evaluation of knee function, was utilized. Twenty-four discoid menisci were assessed as being stable and having a tear in their body. Eight discoid menisci were determined to be unstable (Wrisberg variant) with degeneration within their substance but no meniscus tear. At surgery, the mean age of the patients was 11.81+/−2.62 years (range 5–14 years). The average follow-up was 3.71+/−0.92 years (range, 3–6). The mean preoperative IKDC score was 44.71+/−14.42 (range, 21–57) points. Postoperatively, the mean IKDC score was 81.56+/−1.70 (range, 79–84) points. The two-tailed p -value was < 0.0001. The assumption that MRI assessment is essential not only for detecting the Wrisberg alternate but also for uncovering possible meniscal disintegration and intra-substance alterations that are not usually observed through arthroscopy is supported by our data. [ABSTRACT FROM AUTHOR]

Objective: Chondromalacia patella (CP) describes the softening of the patellar cartilage, and magnetic resonance imaging (MRI) is more useful in diagnosis than other imaging methods. The aim of study is to determine the frequency of other knee MRI fndings and their relationship with chondromalacia stages in patients evaluated for reasons other than trauma and found to have patellar chondromalacia. Methods: This retrospective study included patients who underwent knee MRI examination in the radiology departments of Cukurova University Faculty of Medicine and Health Sciences University Adana Faculty of Medicine for reasons other than trauma between January 2016 and January 2022. Magnetic resonance imaging was used to evaluate the presence and stage of CP, and the outerbridge system was used for staging. As additional fndings, the presence of osteoarthritis, cruciate ligament, meniscus, collateral ligament, and patellar tendon pathologies were evaluated. Results: A total of 278 patients, 168 women and 110 men, with an average age of 59.4 ± 9.8 years, were included in our study. Forty-six patients had stage 1, 64 had stage 2, 66 had stage 3, and 102 had stage 4 CP. A statistically signifcant correlation was found between increasing chondromalacia stage and the presence and stage of osteoarthritis (P < .001), the incidence of anterior cruciate ligament pathology (P < .001), the incidence of tears of the medial meniscus (anterior horn P < .002, posterior horn P < .039), and advanced age (P < .001). Conclusion: It has been determined that there is a relationship between the stage of CP and some additional knee pathologies and advanced age. [ABSTRACT FROM AUTHOR]

Manual anatomical landmarking for morphometric knee bone characterization in orthopedics is highly time-consuming and shows high operator variability. Therefore, automation could be a substantial improvement for diagnostics and personalized treatments relying on landmark-based methods. Applications include implant sizing and planning, meniscal allograft sizing, and morphological risk factor assessment. For twenty MRI-based 3D bone and cartilage models, anatomical landmarks were manually applied by three experts, and morphometric measurements for 3D characterization of the distal femur and proximal tibia were calculated from all observations. One expert performed the landmark annotations three times. Intra- and inter-observer variations were assessed for landmark position and measurements. The mean of the three expert annotations served as the ground truth. Next, automated landmark annotation was performed by elastic deformation of a template shape, followed by landmark optimization at extreme positions (highest/lowest/most medial/lateral point). The results of our automated annotation method were compared with ground truth, and percentages of landmarks and measurements adhering to different tolerances were calculated. Reliability was evaluated by the intraclass correlation coefficient (ICC). For the manual annotations, the inter-observer absolute difference was 1.53 ± 1.22 mm (mean ± SD) for the landmark positions and 0.56 ± 0.55 mm (mean ± SD) for the morphometric measurements. Automated versus manual landmark extraction differed by an average of 2.05 mm. The automated measurements demonstrated an absolute difference of 0.78 ± 0.60 mm (mean ± SD) from their manual counterparts. Overall, 92% of the automated landmarks were within 4 mm of the expert mean position, and 95% of all morphometric measurements were within 2 mm of the expert mean measurements. The ICC (manual versus automated) for automated morphometric measurements was between 0.926 and 1. Manual annotations required on average 18 min of operator interaction time, while automated annotations only needed 7 min of operator-independent computing time. Considering the time consumption and variability among observers, there is a clear need for a more efficient, standardized, and operator-independent algorithm. Our automated method demonstrated excellent accuracy and reliability for landmark positioning and morphometric measurements. Above all, this automated method will lead to a faster, scalable, and operator-independent morphometric analysis of the knee. [ABSTRACT FROM AUTHOR]

Background: Investigation of the association between leg axis alignment and biochemical MRI in young professional soccer players in order to identify a potential influence of the leg axis on cartilage regions at risk. Methods: Sixteen professional soccer players (21 ± 3 years) underwent static and dynamic leg axis analysis via radiation free DIERS formetric 4 D as well as 3-T MRI examination of both knees. Quantitative T2* mapping of the knee cartilage was performed and T2* values were evaluated as 144 regions of interest. Subgroup analysis was performed in players with severe varus alignment (> 6°). Results: Analysis of the leg axis geometry revealed a mean static alignment of 6.6° ± 2.5 varus and a mean dynamic alignment of 5.1° ± 2.6 varus. Quantitative T2* mapping showed significantly increased T2* values in the superficial cartilage layer compared to the deeper region (p < 0.001) as well as a significant increase in relaxation times in the femoral cartilage from anterior to intermediate to posterior (p < 0.001). Combination of both methods revealed a significant correlation for the degree of varus alignment and the femoral, posterior, deep region of the medial knee compartment (r = 0.4; p = 0.03). If severe varus alignment was present this region showed a significant increase in relaxation time compared to players with a less pronounced leg axis deviation (p = 0.003). Conclusion: This study demonstrates that varus alignment in young soccer players is associated with elevated T2* relaxation times in the deep cartilage layer of the medial, posterior, femoral compartment and might therefore be a contributing factor in the early pathogenesis of manifest cartilage lesions. Therefore, these findings should be considered in the development of preventive training programs. [ABSTRACT FROM AUTHOR]

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Introduction: The Wrisberg variant of the discoid lateral meniscus is a very rare disorder and is characterized by the hypermobility and instability of the meniscus caused by the absence of its posterior tibial attachment, with only its meniscofemoral junction (Wrisberg's ligament) maintained, and inserted in the posterior horn of the meniscus. As a result, the posterior horn of the lateral meniscus is mobile; often subluxing into the joint. Materials and methods: A total of eight skeletally immature patients with symptomatic Wrisberg variant of the discoid lateral meniscus were included in this study. Each knee was evaluated with MRI and arthroscopy. We graded unstable discoid menisci according to their discoid morphology (complete vs. incomplete), meniscal intra-substance degeneration, and the presence or absence of meniscal tears. All eight menisci were evaluated as degenerated with no meniscal tears. Five of them were evaluated as complete. Due to the severely degenerated meniscus, we considered it unnecessary to repair the detached posterior tibial ligament, so we performed a reshaping of the discoid meniscus, restoring a C-shape, excising the hypertrophied central part of the meniscus, and creating a posterior horn with a remaining rim of 6–8 mm. For evaluation of the knee function preoperatively and postoperatively we used the online International Knee Documentation Committee (IKDC) system. The purpose of this study is to emphasize the importance of MRI in identifying and revealing the unstable (Wrisberg variant) type of discoid meniscus in children. Results: The mean patient age at the time of surgery was 8.25 ± 2.91 years (range 5–13 years). The average follow-up was 3.75 ± 0.46 years (range 3–4) years. The mean preoperative IKDC score was 22.37 ± 1.50 (range 21–25) points. The mean postoperative IKDC score was 80.50 ± 1.77 (range 79–84) points. Conclusions: MRI is a valuable tool in the evaluation of the shape, stability, and consistency of symptomatic discoid menisci. It is helpful for the detection of the unstable Wrisberg variant. [ABSTRACT FROM AUTHOR]

The UNet has become the golden standard method for the segmentation of 2D medical images that any new method must be validated against. In recent years, a number of variations to the seminal UNet have been proposed with promising results in the papers introducing them. However, there is no clear consensus if any of these architectures generalize as well and the UNet currently remains the methodological golden standard. For the segmentation of 3D scans, UNet‐inspired methods are also dominant, but there is a larger variety across applications. By evaluating the architectures in a different dimensionality, embedded in a different method, and for a different task, we aimed to evaluate if any of these UNet alternatives are promising as a new golden standard that generalizes even better than the UNet. The purpose of this study was to compare UNet inspired models for generalized 3D segmentation. To efficiently segment the 3D scans, we employed each UNet variant architecture as the central 2D segmentation core in the multi‐planar UNet 3D segmentation method that previously demonstrated excellent generalization in the MICCAI Segmentation Decathlon. It would strongly support a claim of generalizability, if a promising UNet‐variant consistently outperforms the UNet in this quite different setting. The experimental results show that the multi‐planar‐based UNet2+ (MPUNet2+) method outperforms other variants including the original multi‐planar UNet (MPUNet). [ABSTRACT FROM AUTHOR]

Purpose: The outcome of a tibial plateau fracture (TPF) depends on the fracture reduction achieved and the extent of soft-tissue lesions, including lesions in the ligaments, cartilage, and menisci. Sub-optimal treatment can result in poor knee function and osteoarthritis. Preoperative planning is primarily based on conventional X-ray and computed tomography (CT), which are unsuitable for diagnosing soft-tissue lesions. Magnetic resonance imaging (MRI) is not routinely performed. To date, no literature exists that clearly states the indications for preoperative MRI. This systematic review aimed to determine the frequency of soft-tissue lesions in TPFs, the association between fracture type and soft-tissue lesions, and the types of cases for which MRI is indicated. Methods: A systematic review of the literature was based on articles located in PubMed/MEDLINE and the Cochrane Central Register of Controlled Trials (CENTRAL), supplemented by searching the included articles' reference lists and the ePublication lists of leading orthopedic and trauma journals. Results: A total of 1138 studies were retrieved. Of these, 18 met the eligibility criteria and included a total of 877 patients. The proportion of total soft-tissue lesions was 93.0%. The proportions of soft-tissue lesions were as follows: medial collateral ligament 20.7%, lateral collateral ligament 22.9%, anterior cruciate ligament 36.8%, posterior cruciate ligament 14.8%, lateral meniscus 48.9%, and medial meniscus 24.5%. A weak association was found between increasing frequency of LCL and ACL lesions and an increase in fracture type according to Schatzker's classification. No standard algorithm for MRI scans of TPFs was found. Conclusion: At least one ligament or meniscal lesion is present in 93.0% of TPF cases. More studies with higher levels of evidence are needed to find out in which particular cases MRI adds value. However, MRI is recommended, at least in young patients and cases of high-energy trauma. [ABSTRACT FROM AUTHOR]

This paper focuses on different types of backbone networks for machine learning architectures which perform classification of knee Magnetic Resonance Imaging (MRI) images. This paper aims to compare different types of feature extraction networks for the same classification task, in terms of accuracy and performance. Multiple variations of machine learning models were trained based on the MRNet architecture, choosing AlexNet, ResNet, VGG-11, VGG-16, and Efficientnet as the backbone. The models were evaluated on the MRNet validation dataset, computing Area Under the Receiver Operating Characteristics Curve (ROC-AUC), accuracy, f1 score, and Cohen's Kappa as evaluation metrics. The MRNet-VGG16 model variant shows the best results for Anterior Cruciate Ligament (ACL) tear detection. For general abnormality detection, MRNet-VGG16 is dominated by MRNet-Resnet in confidence between 0.5 and 0.75 and by MRNet-VGG11 for confidence more than 0.8. Due to the non-uniform nature of backbone network performance on different MRI planes, it is advisable to use an LR ensemble of: VGG16 on a coronal plane for all classification tasks; on an axial plane for abnormality and ACL tear detection; Alexnet on a sagittal plane for abnormality detection, and an axial plane for meniscal tear detection; and VGG11 on a sagittal plane for ACL tear detection. The results also indicate that the Cohen's Kappa metric is valuable in model evaluation for the MRNet dataset, as it provides deeper insights on classification decisions. [ABSTRACT FROM AUTHOR]

Purpose: Many children who undergo MR of the knee to evaluate traumatic injury may not undergo a separate dedicated evaluation of their skeletal maturity, and we wished to investigate how accurately skeletal maturity could be automatically inferred from knee MRI using deep learning to offer this additional information to clinicians.Materials and Methods: Retrospective data from 894 studies from 783 patients were obtained (mean age 13.1 years, 47% female). Coronal and sagittal sequences that were T1/PD-weighted were included and resized to 224 × 224 pixels. Data were divided into train (n = 673), tune (n = 48), and test (n = 173) sets, and children were separated across sets. The chronologic age was predicted using deep learning approaches based on a long short-term memory (LSTM) model, which took as input DenseNet-121-extracted features from all T1/PD coronal and sagittal slices. Each test case was manually assigned a bone age by two radiology residents using a reference atlas provided by Pennock and Bomar. The patient's age served as ground truth.Results: The error of the model's predictions for chronological age was not significantly different from that of radiology residents (model M.S.E. 1.30 vs. resident 0.99, paired t-test = 1.47, p = 0.14). Pearson correlation between model and resident prediction of chronologic age was 0.96 (p < 0.001).Conclusion: A deep learning-based approach demonstrated ability to infer skeletal maturity from knee MR sequences that was not significantly different from resident performance and did so in less than 2% of the time required by a human expert. This may offer a method for automatically evaluating lower extremity skeletal maturity automatically as part of every MR examination. [ABSTRACT FROM AUTHOR]

Aim: This study has the primary objective of studying the effect of Wharton jelly mesenchymal stem cells (WJMSCs) in the treatment of knee osteoarthritis. As a secondary end point, we report on the efficacy of such therapy. Patients and methods: 16 patients with advanced Kellgren stage were treated using two doses of expanded WJMSCs given 1 month apart. Patients were followed for 48 months using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and 12 months using magnetic resonance imaging (MRI). Results: Treatment was well tolerated. One patient developed moderate effusion and one superficial phlebitis. We observed functional and pain improvement at 12 and 48 months (p < 0.0001), with statistically significant improvement on MRI scans at 12 months in cartilage loss, osteophytes, bone marrow lesions, effusion and synovitis (p < 0.01), and highly significant improvement in subchondral sclerosis (p < 0.0001). Conclusion: WJMSCs are safe and potentially effective in producing significant improvement in KOOS and MRI scores when administered intra-articularly in knee osteoarthritis cases under ultrasound guidance. [ABSTRACT FROM AUTHOR]

Objective: To assess the accuracy of routine knee MRI in detecting acute popliteal artery and/or common peroneal nerve (CPN) dysfunction following multiligamentous knee injury (MLKI), with correlation of MRI findings to clinical outcome. Materials and methods: Routine MRI knee examinations in 115 MLKI patients (54/115 with acute neurovascular injury, 61/115 without neurovascular injury) were retrospectively reviewed. Cases were classified by injury mechanism and ligamentous injuries sustained. MRI examinations were reviewed by two readers for vascular (arterial flow void, arterial calibre, intimal flap, perivascular hematoma) and CPN (intraneural T2-hyperintensity, calibre, discontinuity, perineural hematoma) injuries. Accuracy of routine knee MRI in the diagnosis of acute neurovascular injury and correlation of MRI findings to clinical outcome were evaluated. Results: Patients included 86/115 males, mean age 33 years. The accuracy of MRI in diagnosis of acute CPN injury was 80.6%, 83.6% (readers 1 and 2): sensitivity (78%, 79.7%), specificity (80%, 86.7%), PPV (78%, 82.5%), and NPV (82.7%, 84.4%). Increased intraneural T2 signal showed a significant correlation to acute CPN dysfunction (p < 0.05). MRI was 75%, 69.8% (readers 1 and 2) accurate in detecting acute vascular injury: sensitivity (73.3%, 86.7%), specificity (75.2%, 67.3%), PPV (30.5%, 36.1%), and NPV (95%, 97.1%). No MRI features of vascular injury showed a statistical correlation with clinical outcome. Neurovascular complications were more common in ultra-low-energy injuries and KD-V3L pattern of ligament disruption. Conclusion: Routine MRI is of limited accuracy in assessing vascular complication, but higher accuracy in assessing CPN injury following MLKI. Increased intraneural T2 signal on conventional knee MR imaging shows statistically significant association with clinically documented acute CPN dysfunction following MLKI. [ABSTRACT FROM AUTHOR]

Purpose: The medical examination ("medical") is an important procedure in professional soccer since it has high economic relevance. In addition to clinical tests, magnetic resonance imaging (MRI) is used to assess joint health. In the present study, the reliability of semiquantitative knee MRI during the "medical" in professional soccer was tested, and its relationship with clinical data and days missed due to knee injury was observed. Methods: In this cross-sectional study, between 2012 and 2019, 69 newly assigned players (age 18–35 years) from a professional soccer club underwent MRI (3.0 T) of both knee joints during their "medical". Reported knee injuries and previously missed days due to injury were obtained from player anamnesis and the "transfermarkt.com" database. Based on the established "Whole-Organ Magnetic Resonance Imaging Score" (WORMS), two independent radiologists graded the MRI results. Further evaluation was based on the mean score of both knees. Results: The mean WORMS for all subjects was 13.9 (median 10.5, range 0–61). Players with previous injuries had significantly higher scores than players without reported injuries (22.1 ± 17.7 vs. 8.9 ± 4.4, p < 0.002). Three outliers (previously undetected injuries) in the group of players without reported injuries were observed (6.7%). The WORMS was significantly correlated with a prior knee injury (r: 0.424, p < 0.0001) and days missed due to injury (r: 0.489, p < 0.001). Age was correlated with the WORMS (r: 0.386, p < 0.001). In a linear regression model, prior injury was the only significant predictor of a high WORMS (p = 0.001). The WORMS was a significant predictor of days missed due to injury (p < 0.0002) and prior injury (sensitivity: 78%, specificity: 91%, p = 0.006). The intraclass correlation coefficient was excellent (0.89). Conclusion: Semiquantitative knee MRI for WORMS determination during the soccer "medical" is a robust and reliable method. Prior injury, even in players without documented trauma, was detected by the WORMS, and previously missed days due to injury were correlated with the semiquantitative MR knee score. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]

Purpose: The three-dimensional (3D) sequence of magnetic resonance imaging (MRI) plays a critical role in the imaging of musculoskeletal joints; however, its long acquisition time limits its clinical application. In such conditions, compressed sensing (CS) is introduced to accelerate MRI in clinical practice. We aimed to investigate the feasibility of an isotropic 3D variable-flip-angle fast spin echo (FSE) sequence with CS technique (CS-MATRIX) compared to conventional 2D sequences in knee imaging. Methods: Images from different sequences of both the accelerated CS-MATRIX and the corresponding conventional acquisitions were prospectively analyzed and compared. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the structures within the knees were measured for quantitative analysis. The subjective image quality and diagnostic agreement were compared between CS-MATRIX and conventional 2D sequences. Quantitative and subjective image quality scores were statistically analyzed with the paired t-test and Wilcoxon signed-rank test, respectively. Diagnostic agreements of knee substructure were assessed using Cohen's weighted kappa statistic. Results: For quantitative analysis, images from the CS-MATRIX sequence showed a significantly higher SNR than T2-fs 2D sequences for visualizing cartilage, menisci, and ligaments, as well as a higher SNR than proton density (pd) 2D sequences for visualizing menisci and ligaments. There was no significant difference between CS-MATRIX and 2D T2-fs sequences in subjective image quality assessment. The diagnostic agreement was rated as moderate to very good between CS-MATRIX and 2D sequences. Conclusion: This study demonstrates the feasibility and clinical potential of the CS-MATRIX sequence technique for detecting knee lesions The CS-MATRIX sequence allows for faster knee imaging than conventional 2D sequences, yielding similar image quality to 2D sequences. [ABSTRACT FROM AUTHOR]

Background & Objectives: Knee is the largest synovial joint in the body. Although FSE PD (fast spin echo proton density) imaging technique for the diagnosis of meniscal tear has replaced CSE PD (conventional spin echo proton density) technique in many MRI centers, several studies have questioned the effectiveness of FSE PD technique in diagnosis of meniscal tear. In this study, the diagnostic values of CSE PD and FSE PD techniques in evaluation of meniscus tear are compared. Materials: In this study, using CSE PD and FSE PD techniques, MRI was performed on 67 knees of patients with suspected meniscal tear referring to the MRI Center of Imam Reza Hospital (Kermanshah, Iran). Diagnostic arthroscopy was also performed for all patients. The data were entered SPSS version 20, and finally the results of MRI reports of the two techniques were compared in evaluation of meniscal tear taking into account the arthroscopic findings as the gold standard. Results: According to the results of this study, no significant difference was found in specificity and positive predictive value of the two techniques. However, the sensitivity and negative predictive values were significantly different, in such a way that the related values were 97% and 97% in the CSE PD technique and 69% and 73% in the FSE PD technique, respectively. Conclusion: Due to low sensitivity and high false negative results, MRI using FSE PD technique is not recommended as an alternative for CSE PD technique in evaluation of meniscal tear. [ABSTRACT FROM AUTHOR]

Objective: To assess the accuracy of routine knee MRI in detecting acute popliteal artery and/or common peroneal nerve (CPN) dysfunction following multiligamentous knee injury (MLKI), with correlation of MRI findings to clinical outcome. Materials and methods: Routine MRI knee examinations in 115 MLKI patients (54/115 with acute neurovascular injury, 61/115 without neurovascular injury) were retrospectively reviewed. Cases were classified by injury mechanism and ligamentous injuries sustained. MRI examinations were reviewed by two readers for vascular (arterial flow void, arterial calibre, intimal flap, perivascular hematoma) and CPN (intraneural T2-hyperintensity, calibre, discontinuity, perineural hematoma) injuries. Accuracy of routine knee MRI in the diagnosis of acute neurovascular injury and correlation of MRI findings to clinical outcome were evaluated. Results: Patients included 86/115 males, mean age 33 years. The accuracy of MRI in diagnosis of acute CPN injury was 80.6%, 83.6% (readers 1 and 2): sensitivity (78%, 79.7%), specificity (80%, 86.7%), PPV (78%, 82.5%), and NPV (82.7%, 84.4%). Increased intraneural T2 signal showed a significant correlation to acute CPN dysfunction (p < 0.05). MRI was 75%, 69.8% (readers 1 and 2) accurate in detecting acute vascular injury: sensitivity (73.3%, 86.7%), specificity (75.2%, 67.3%), PPV (30.5%, 36.1%), and NPV (95%, 97.1%). No MRI features of vascular injury showed a statistical correlation with clinical outcome. Neurovascular complications were more common in ultra-low-energy injuries and KD-V3L pattern of ligament disruption. Conclusion: Routine MRI is of limited accuracy in assessing vascular complication, but higher accuracy in assessing CPN injury following MLKI. Increased intraneural T2 signal on conventional knee MR imaging shows statistically significant association with clinically documented acute CPN dysfunction following MLKI. [ABSTRACT FROM AUTHOR]

Background: Clinical knee MRI protocols require upwards of 15 minutes of scan time. Purpose/Hypothesis: To compare the imaging appearance of knee abnormalities depicted with a 5‐minute 3D double‐echo in steady‐state (DESS) sequence with separate echo images, with that of a routine clinical knee MRI protocol. A secondary goal was to compare the imaging appearance of knee abnormalities depicted with 5‐minute DESS paired with a 2‐minute coronal proton‐density fat‐saturated (PDFS) sequence. Study Type: Prospective. Subjects: Thirty‐six consecutive patients (19 male) referred for a routine knee MRI. Field Strength/Sequences: DESS and PDFS at 3T. Assessment: Five musculoskeletal radiologists evaluated all images for the presence of internal knee derangement using DESS, DESS+PDFS, and the conventional imaging protocol, and their associated diagnostic confidence of the reading. Statistical Tests: Differences in positive and negative percent agreement (PPA and NPA, respectively) and 95% confidence intervals (CIs) for DESS and DESS+PDFS compared with the conventional protocol were calculated and tested using exact McNemar tests. The percentage of observations where DESS or DESS+PDFS had equivalent confidence ratings to DESS+Conv were tested with exact symmetry tests. Interreader agreement was calculated using Krippendorff's alpha. Results: DESS had a PPA of 90% (88–92% CI) and NPA of 99% (99–99% CI). DESS+PDFS had increased PPA of 99% (95–99% CI) and NPA of 100% (99–100% CI) compared with DESS (both P < 0.001). DESS had equivalent diagnostic confidence to DESS+Conv in 94% of findings, whereas DESS+PDFS had equivalent diagnostic confidence in 99% of findings (both P < 0.001). All readers had moderate concordance for all three protocols (Krippendorff's alpha 47–48%). Data Conclusion: Both 1) 5‐minute 3D‐DESS with separated echoes and 2) 5‐minute 3D‐DESS paired with a 2‐minute coronal PDFS sequence depicted knee abnormalities similarly to a routine clinical knee MRI protocol, which may be a promising technique for abbreviated knee MRI. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018. [ABSTRACT FROM AUTHOR]

Background: Clinical knee MRI protocols require upwards of 15 minutes of scan time.Purpose/hypothesis: To compare the imaging appearance of knee abnormalities depicted with a 5-minute 3D double-echo in steady-state (DESS) sequence with separate echo images, with that of a routine clinical knee MRI protocol. A secondary goal was to compare the imaging appearance of knee abnormalities depicted with 5-minute DESS paired with a 2-minute coronal proton-density fat-saturated (PDFS) sequence.Study Type: Prospective.Subjects: Thirty-six consecutive patients (19 male) referred for a routine knee MRI.Field Strength/sequences: DESS and PDFS at 3T.Assessment: Five musculoskeletal radiologists evaluated all images for the presence of internal knee derangement using DESS, DESS+PDFS, and the conventional imaging protocol, and their associated diagnostic confidence of the reading.Statistical Tests: Differences in positive and negative percent agreement (PPA and NPA, respectively) and 95% confidence intervals (CIs) for DESS and DESS+PDFS compared with the conventional protocol were calculated and tested using exact McNemar tests. The percentage of observations where DESS or DESS+PDFS had equivalent confidence ratings to DESS+Conv were tested with exact symmetry tests. Interreader agreement was calculated using Krippendorff's alpha.Results: DESS had a PPA of 90% (88-92% CI) and NPA of 99% (99-99% CI). DESS+PDFS had increased PPA of 99% (95-99% CI) and NPA of 100% (99-100% CI) compared with DESS (both P < 0.001). DESS had equivalent diagnostic confidence to DESS+Conv in 94% of findings, whereas DESS+PDFS had equivalent diagnostic confidence in 99% of findings (both P < 0.001). All readers had moderate concordance for all three protocols (Krippendorff's alpha 47-48%).Data Conclusion: Both 1) 5-minute 3D-DESS with separated echoes and 2) 5-minute 3D-DESS paired with a 2-minute coronal PDFS sequence depicted knee abnormalities similarly to a routine clinical knee MRI protocol, which may be a promising technique for abbreviated knee MRI.Level Of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018. [ABSTRACT FROM AUTHOR]

Purpose: To demonstrate and evaluate the scan time and quantitative accuracy of simultaneous bilateral‐knee imaging compared with single‐knee acquisitions. Methods: Hardware modifications and safety testing was performed to enable MR imaging with two 16‐channel flexible coil arrays. Noise covariance and sensitivity‐encoding g‐factor maps for the dual‐coil‐array configuration were computed to evaluate coil cross‐talk and noise amplification. Ten healthy volunteers were imaged on a 3T MRI scanner with both dual‐coil‐array bilateral‐knee and single‐coil‐array single‐knee configurations. Two experienced musculoskeletal radiologists compared the relative image quality between blinded image pairs acquired with each configuration. Differences in T2 relaxation time measurements between dual‐coil‐array and single‐coil‐array acquisitions were compared with the standard repeatability of single‐coil‐array measurements using a Bland‐Altman analysis. Results: The mean g‐factors for the dual‐coil‐array configuration were low for accelerations up to 6 in the right–left direction, and minimal cross‐talk was observed between the two coil arrays. Image quality ratings of various joint tissues showed no difference in 89% (95% confidence interval: 85–93%) of rated image pairs, with only small differences (“slightly better” or “slightly worse”) in image quality observed. The T2 relaxation time measurements between the dual‐coil‐array configuration and the single‐coil configuration showed similar limits of agreement and concordance correlation coefficients (limits of agreement: −0.93 to 1.99 ms; CCC: 0.97 (95% confidence interval: 0.96–0.98)), to the repeatability of single‐coil‐array measurements (limits of agreement: −2.07 to 1.96 ms; CCC: 0.97 (95% confidence interval: 0.95–0.98)). Conclusion: A bilateral coil‐array setup can image both knees simultaneously in similar scan times as conventional unilateral knee scans, with comparable image quality and quantitative accuracy. This has the potential to improve the value of MRI knee evaluations. Magn Reson Med 80:529–537, 2018. © 2017 International Society for Magnetic Resonance in Medicine. [ABSTRACT FROM AUTHOR]

A fully automated knee magnetic resonance imaging (MRI) segmentation method to study osteoarthritis (OA) was developed using a novel hierarchical set of random forests (RF) classifiers to learn the appearance of cartilage regions and their boundaries. A neighborhood approximation forest is used first to provide contextual feature to the second-level RF classifier that also considers local features and produces location-specific costs for the layered optimal graph image segmentation of multiple objects and surfaces (LOGISMOS) framework. Double-echo steady state MRIs used in this paper originated from the OA Initiative study. Trained on 34 MRIs with varying degrees of OA, the performance of the learning-based method tested on 108 MRIs showed significant reduction in segmentation errors ( p<\textsf 0.05 ) compared with the conventional gradient-based and single-stage RF-learned costs. The 3-D LOGISMOS was extended to longitudinal-3-D (4-D) to simultaneously segment multiple follow-up visits of the same patient. As such, data from all time-points of the temporal sequence contribute information to a single optimal solution that utilizes both spatial 3-D and temporal contexts. 4-D LOGISMOS validation on 108 MRIs from baseline, and 12 month follow-up scans of 54 patients showed significant reduction in segmentation errors ( p<\textsf 0.01 ) compared with 3-D. Finally, the potential of 4-D LOGISMOS was further explored on the same 54 patients using five annual follow-up scans demonstrating a significant improvement of measuring cartilage thickness ( p<\textsf 0.01 ) compared with the sequential 3-D approach. [ABSTRACT FROM PUBLISHER]

Background: Majority of musculoskeletal cross-sectional imaging requests have a non-revealing and non-specific clinical history of pain. However, the location of pain is very relevant towards arriving at a specific orthopedic diagnosis. The purpose of this research was to study the impact of skin marker placement and training of technologists prior to knee MRI in detection of clinically important findings.Methods: Total 200 consecutive left knee MRIs were evaluated before and after technologist training with regards to marker placement at the site of clinical symptoms or palpable finding. Marker location in relation to the knee was recorded and important findings were classified as correlated important finding, non-correlated important finding, other compartment important finding in non-correlated cases, and diffuse abnormality, i.e. tri-compartmental cartilage defects in both correlated and non-correlated cases. Differences among scans before and after technologist training were analyzed.Results: The marker placement was observed in higher proportion of patients in post-training scans (78% vs 60%, p = 0.00). The most common location of the marker was in anterior or anterolateral knee (32% and 34% cases, respectively). The marker-important finding correlation was also higher post training, but not statistically significant (53% versus 38%, p = 0.57). Important findings correlated with the marker in more than 50% of the scans in the post-training set.Conclusion: Marker placement can aid in detection of clinically important imaging finding and technologist training aids in increased rates of marker placement and improved correlation. [ABSTRACT FROM AUTHOR]

Purpose To introduce a method for obtaining fat-suppressed images in real-time MRI of moving joints at 3 Tesla (T) using a bSSFP sequence with phase detection to enhance visualization of soft tissue structures during motion. Methods The wrist and knee of nine volunteers were imaged with a real-time bSSFP sequence while performing dynamic tasks. For appropriate choice of sequence timing parameters, water and fat pixels showed an out-of-phase behavior, which was exploited to reconstruct water and fat images. Additionally, a 2-point Dixon sequence was used for dynamic imaging of the joints, and resulting water and fat images were compared with our proposed method. Results The joints could be visualized with good water-fat separation and signal-to-noise ratio (SNR), while maintaining a relatively high temporal resolution (5 fps in knee imaging and 10 fps in wrist imaging). The proposed method produced images of moving joints with higher SNR and higher image quality when compared with the Dixon method. Conclusions Water-fat separation is feasible in real-time MRI of moving knee and wrist at 3 T. PS-bSSFP offers movies with higher SNR and higher diagnostic quality when compared with Dixon scans. Magn Reson Med 78:58-68, 2017. © 2016 International Society for Magnetic Resonance in Medicine [ABSTRACT FROM AUTHOR]

Purpose: To develop and clinically evaluate a pediatric knee magnetic resonance imaging (MRI) technique based on volumetric fast spin-echo (3DFSE) and compare its diagnostic performance, image quality, and imaging time to that of a conventional 2D protocol.Materials and Methods: A 3DFSE sequence was modified and combined with a compressed sensing-based reconstruction resolving multiple image contrasts, a technique termed T2 Shuffling (T2 Sh). With Institutional Review Board (IRB) approval, 28 consecutive children referred for 3T knee MRI prospectively underwent a standard clinical knee protocol followed by T2 Sh. T2 Sh performance was assessed by two readers blinded to diagnostic reports. Interpretive discrepancies were resolved by medical record chart review and consensus between the readers and an orthopedic surgeon. Image quality was evaluated by rating anatomic delineation, with 95% confidence interval. A Wilcoxon rank-sum test assessed the null hypothesis that T2 Sh structure delineation compared to conventional 2D is unchanged. Intraclass correlation coefficients were calculated for interobserver agreement. Imaging time of the conventional protocol and T2 Sh was compared.Results: There was 81% and 87% concordance between T2 Sh reports and diagnostic reports, respectively, for each reader. Upon consensus review, T2 Sh had 93% sensitivity and 100% specificity compared to clinical reports for detection of clinically relevant findings. The 95% confidence interval of diagnostic or better rating was 95-100%, with 34-80% interobserver agreement. There was no significant difference in structure delineation between T2 Sh and 2D, except for the retinaculum (P < 0.05), where 2D was preferred. Typical imaging time for T2 Sh and the conventional exam was 7 and 13 minutes, respectively.Conclusion: A single-sequence pediatric knee exam is feasible with T2 Sh, providing multiplanar, reformattable 4D images.Level Of Evidence: 2 J. MAGN. RESON. IMAGING 2017;45:1700-1711. [ABSTRACT FROM AUTHOR]

Anterior cruciate and posterior cruciate injuries rarely occur in isolation and are often associated with injuries to the secondary or supporting structures that provide stability against rotational forces. These structures include the posterolateral and posteromedial corner ligaments and tendons, as well as the anterolateral ligament. If injuries to these secondary structures are not appreciated at the time of cruciate ligament reconstruction, an isolated cruciate ligament reconstruction may be predisposed to early failure. Thus it is crucial for radiologists interpreting knee magnetic resonance imaging to understand and report on injury to these ligaments and tendons at the time of initial injury to help the orthopaedic surgeon plan a comprehensive approach to ligament reconstruction. This strategy will ultimately result in improved patient outcomes. [ABSTRACT FROM AUTHOR]

Purpose: To compare a faster, new, high-resolution accelerated 3D-fast-spin-echo (3D-FSE) acquisition sequence (CS-SPACE) to traditional 2D and high-resolution 3D sequences for knee 3-T magnetic resonance imaging (MRI).Materials and Methods: Twenty patients received knee MRIs that included routine 2D (T1, PD ± FS, T2-FS; 0.5 × 0.5 × 3 mm3; ∼10 min), traditional 3D FSE (SPACE-PD-FS; 0.5 × 0.5 × 0.5 mm3; ∼7.5 min), and accelerated 3D-FSE prototype (CS-SPACE-PD-FS; 0.5 × 0.5 × 0.5 mm3; ∼5 min) acquisitions on a 3-T MRI system (Siemens MAGNETOM Skyra). Three musculoskeletal radiologists (MSKRs) prospectively and independently reviewed the studies with graded surveys comparing image and diagnostic quality. Tissue-specific signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were also compared.Results: MSKR-perceived diagnostic quality of cartilage was significantly higher for CS-SPACE than for SPACE and 2D sequences (p < 0.001). Assessment of diagnostic quality of menisci and synovial fluid was higher for CS-SPACE than for SPACE (p < 0.001). CS-SPACE was not significantly different from SPACE but had lower assessments than 2D sequences for evaluation of bones, ligaments, muscles, and fat (p ≤ 0.004). 3D sequences had higher spatial resolution, but lower overall assessed contrast (p < 0.001). Overall image quality from CS-SPACE was assessed as higher than SPACE (p = 0.007), but lower than 2D sequences (p < 0.001). Compared to SPACE, CS-SPACE had higher fluid SNR and CNR against all other tissues (all p < 0.001).Conclusions: The CS-SPACE prototype allows for faster isotropic acquisitions of knee MRIs over currently used protocols. High fluid-to-cartilage CNR and higher spatial resolution over routine 2D sequences may present a valuable role for CS-SPACE in the evaluation of cartilage and menisci. [ABSTRACT FROM AUTHOR]

Purpose: The medial patellofemoral ligament (MPFLL)/lateral patellar retinaculum (LPR) ratio were assessed in knees as a means to detect patellar malalignment. We also aimed to evaluate the prevalence of the various types of trochlear dysplasia in patients with patellar malalignment. Materials and methods: After approval of our institutional ethics committee, we conducted a retrospective study that included 450 consecutive patients to evaluate them for the presence of patellar malalignment. Parameters investigated were the trochlear type, sulcus angle, presence of a supratrochlear spur, MPFLL, LPR, patella alta, and patella baja by means of 1.5T magnetic resonance imaging (MRI). Overall, 133 patients were excluded because of the presence of major trauma, multiple ligament injuries, bipartite patella, and/or previous knee surgery. The Dejour classification was used to assess trochlear dysplasia. Two experienced radiologists (HKY, EEE) evaluated the images. Their concordance was assessed using the kappa (κ) test. Results: The frequencies of patellar malalignment and trochlear dysplasia were 34.7 and 63.7 %, respectively. The frequency of trochlear dysplasia associated with patellar malalignment was 97.2 %. An MPFLL/LPR ratio of 1.033-1.041 had high sensitivity and specificity for malalignment. The researchers' concordance was good (κ = 0.89, SE = 0.034, P < 0.001). Conclusion: Trochlear dysplasia is frequently associated with patellar malalignment. An increased MPFLL/LPR ratio is useful for detecting patellar malalignment on knee MRI, which is a novel quantitative method based on ligament length. [ABSTRACT FROM AUTHOR]

Objectives: Many studies show that a large portion of medical prescriptions for diagnostic examinations may be not useful for patient's management or unnecessary. Rapid technological advancement has made it possible for magnetic resonance imaging (MRI) to be increasingly used all over the world, particularly for musculoskeletal disorders. The aim of this study was to assess the appropriateness of the knee MRI prescriptions. Materials and methods: A panel of experts found standard clinical practice guidelines in the management of knee disorders. Secondly, the finalized set of guidelines chosen was compared with the data of 400 patients who underwent previous knee MRIs, which were then reported in a specific questionnaire prepared by the authors. The rate of appropriateness of knee MRI prescriptions was then calculated. Results: Almost 21 % of prescriptions were totally inappropriate, 18.8 % were uncertain, and 60.2 % could be considered totally appropriate. The most frequent prescription indication was for meniscal disorders that account for 26.8 % of the total indications. Conclusions: Our results demonstrate that approximately 40 % of the total prescriptions were totally inappropriate or uncertain and that most of these were made by general practitioners. In light of these results, the economic impact of inappropriate prescriptions on the Italian healthcare system has to be seriously considered. [ABSTRACT FROM AUTHOR]

The aim of this study is to fabricate and test a novel flexible flat cable antenna (FFCA) for MRI of the knee at different flexion angles. The FFCA was made of a flat cable, a tuning/matching circuit and a signal transmission line. To test its feasibility and validity, in vitro and in vivo experiments were carried out on a 3.0 T MR scanner. The in vitro experiment suggested that the proposed FFCA could achieve a high signal-to-noise ratio (SNR) of 336, while the SNR of an eight-channel knee coil was 291, and phantom images from the FFCA are homogeneously distributed. In the in vivo experiment, the FFCA had a higher SNR of 169 in the region of interest and more than 48.5 cm of longitudinal coverage, while the corresponding values for the commercial coil were 153 and 22.5 cm. Finally, five sagittal knee images at different flexion angles were acquired. The FFCA could acquire satisfactory knee images at different flexion angles, with the advantages of simplicity, low cost, large field of view and high SNR. It may therefore be further used to improve MR image quality of the knee joint. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

MR-based methods provide low risk, noninvasive assessment of joint kinematics; however, these methods often use static positions or require many identical cycles of movement. The study objective was to compare the 3D kinematic results approximated from a series of sequential static poses of the knee with the 3D kinematic results obtained from continuous dynamic movement of the knee. To accomplish this objective, we compared kinematic data from a validated static MR method to a fast static MR method, and compared kinematic data from both static methods to a newly developed dynamic MR method. Ten normal volunteers were imaged using the three kinematic methods (dynamic, static standard, and static fast). Results showed that the two sets of static results were in agreement, indicating that the sequences (standard and fast) may be used interchangeably. Dynamic kinematic results were significantly different from both static results in eight of 11 kinematic parameters: patellar flexion, patellar tilt, patellar proximal translation, patellar lateral translation, patellar anterior translation, tibial abduction, tibial internal rotation, and tibial anterior translation. Three-dimensional MR kinematics measured from dynamic knee motion are often different from those measured in a static knee at several positions, indicating that dynamic-based kinematics provides information that is not obtainable from static scans. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To compare magnetic resonance (MR) signal intensity in the medial meniscus at the time of displacement and after its reduction in patients with a displaced bucket-handle tear of the meniscus associated with anterior cruciate ligament (ACL) injury. Methods: Nine chronic ACL-deficient patients (3 male, 6 female, mean age 29 years) with locking due to a displaced fragment of the medial meniscus following a bucket-handle tear were involved in this study. In all patients, the following two-stage surgeries were planned as follows: first operation, arthroscopic reduction of the meniscus; second operation, meniscal repair and ACL reconstruction after immobilization for 1-2 weeks. Magnetic resonance imaging (MRI) evaluation using coronal T2*-weighted images was performed when the knee was locked and after the meniscus was reduced. Signal intensity before and after meniscal reduction was compared in the same patients. Results: In 8 of the 9 patients, the displaced fragment exhibited high signal intensity in 1 patient and mildly high in 7 patients. After its reduction, the signal intensity changed to low in all 8 patients. Conclusions: A high-intensity signal in the displaced fragment of the medial meniscus may change to low after its reduction to its original position. Therefore, at the time of decision-making regarding meniscus repair for a displaced meniscus in a locked knee, surgeons should give priority to arthroscopic findings rather than to signal intensity on MRI. Level of evidence: Diagnostic study, Level III. [ABSTRACT FROM AUTHOR]

Background. Complete rupture of the anterior cruciate ligament (ACL) does not represent a diagnostic problem for the standard magnetic resonance (MR) protocol of the knee. Lower accuracy of the standard MR protocol for partial rupture of the ACL can be improved by using additional, dedicated MR techniques. The study goal was to draw a comparison between sagittal-oblique MR technique of ACL imaging versus flexion MR technique of ACL imaging and, versus ACL imaging obtained with standard MR protocol of the knee. Patients and methods. In this prospective study we included 149 patients who were referred to magnetic resonance imaging (MRI) examination due to knee soft tissues trauma during 12 months period. MRI signs of ACL trauma, especially detection of partial tears, number of slices per technique showing the whole ACL, duration of applied additional protocols, and reproducibility of examination were analysed. Results. Accuracy of standard MRI protocol of the knee comparing to both additional techniques is identical in detection of a complete ACL rupture. Presentations of the partial ruptures of ACL using flexion technique and sagittaloblique technique were more sensitive (p<0.001) than presentation using standard MR protocol. There was no statistically significant difference between MRI detection of the ruptured ACL between additional techniques (p> 0.65). Sagittal-oblique technique provides a higher number of MRI slices showing the whole course of the ACL and requires a shorter scan time compared to flexion technique (p<0.001). Conclusions. Both additional techniques (flexion and sagittal-oblique) are just as precise as the standard MR protocol for the evaluation of a complete rupture of the ACL, so they should be used in cases of suspicion of partial rupture of the ACL. Our study showed sagittal-oblique technique was superior, because it did not depend on patient's ability to exactly repeat the same external rotation if standard MR protocol was used or to repeat exactly the same flexion in flexion MR technique in further MR examinations. Sagittal-oblique technique does not require the patient's knee to be repositioned, which makes this technique faster. We propose this technique in addition to the standard MR protocol for detection of partial ACL tears. [ABSTRACT FROM AUTHOR]

The article discusses the study on analyzing rotational limb alignment in patients with patellofemoral instability using magnetic resonance imaging (MRI) and comparing them with the reports of individuals with a previous patellar dislocation. It concludes that few patients with nontraumatic patellar instability have greater internal femoral and greater knee rotation, and a tendency for genu valgum as compared to healthy individuals.

Osteoarthritis (OA) of the knee is a common, debilitating condition. Twelve percent of people aged 60 years or older have symptomatic knee OA. With increasing global incidence of obesity, the prevalence of OA is set to dramatically rise Cartilage deterioration is a hallmark of the disease, but other areas are equally as important, such as changes to the subchondral bone. Magnetic resonance imaging (MRI) has enabled us to view bone marrow lesions (BMLs) in the subchondral bone, allowing progress to be made in understanding their natural history, effect on pain, structural deterioration and other factors. The focus of this review is to try to put a new clinical perspective for the patients with BMLs in relation to pain, functional decline and prognosis. [ABSTRACT FROM AUTHOR]

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Objective: Although the popliteomeniscal fascicles are important stabilizers of the lateral meniscus, there have been few studies of their MR appearance. We wished to determine: (1) whether the fascicles are normally seen on MR imaging, and (2) whether certain imaging factors influenced their visualization.Design and Patients: We reviewed the sagittal MR images of 66 consecutive patients who had no evidence of injury to the lateral compartment. We determined the frequencies of MR visualization of the superior and inferior popliteomeniscal fascicles, and whether visualization was affected by the weighting of spin echo sequences, the presence of a joint effusion, slice placement relative to the fascicles, and windowing of the images.Results and Conclusions: Both popliteomeniscal fascicles were seen in 64 of the 66 patients. The fascicles were better seen on T2-weighted images than on proton-density weighted images (P<0.01). On the T2-weighted images, fascicle visualization was not significantly affected by the presence or absence of an effusion, slice placement or image windowing (P=0.2 to 1.0). On proton-density weighted images, fascicle visualization was significantly improved when high-contrast windowing was used (P=0.04). In conclusion, we found that the popliteomeniscal fascicles are normally seen on MR imaging of the knee when there are no lateral compartment injuries. The fascicles are significantly better visualized on T2-weighted than on proton-density weighted images. Visualization is not significantly affected by the presence of an effusion or slice placement. [ABSTRACT FROM AUTHOR]

ABSTRACT MRI has assumed a major role in investigating disorders of the knee, especially internal derangement. We correlated the MRI report and arthroscopic findings of 18 patients with suspected meniscal or ligament injury. The results are presented and compared with other series. A particularly important asset of MRI is its very high negative predictive value. [ABSTRACT FROM AUTHOR]

In order to evaluate the normal amount of intra-articular fluid on knee MRI, we examined 36 knees of 18 normal volunteers on a 1.5-T MR system. Sagittal spin-echo T2-weighted images were obtained. We measured the maximum thickness and length of fluid seen in the suprapatellar pouch and in the posterior recesses of the joint. We also looked for fluid in other areas of the knee. The maximum thickness of fluid seen in the suprapatellar pouch was between 0 and 5 mm in all but three cases, where it reached 6, 8 and 9 mm. The maximal thickness of fluid seen in the posterior recesses of the joint was between 0 and 5 mm in all but two cases where it was 6 and 7 mm. The maximum lengths of fluid in the suprapatellar pouch and posterior recesses were much more variable than thickness and appear of less interest in establishing normal limits. We conclude that the best and easiest way to quantify fluid in the knee joint is to measure its maximum thickness in the suprapatellar pouch and in the posterior recesses. Normal values in these two areas is generally between 0 and 5 mm; in rare cases, it can be between 6 and 9 mm. When the maximum thickness in one of these two areas reach 10 mm or more, a pathological joint effusion should be suspected. [ABSTRACT FROM AUTHOR]