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PURPOSE: To determine the relationship between femoral–tibial morphometries and anterior cruciate ligament (ACL) pathologies using magnetic resonance imaging (MRI). METHODS: We retrospectively evaluated 455 patients (211 females and 244 males) who underwent knee MRI with suspected ACL pathology. Imaging findings were classified as normal ACL (n = 119), degeneration of the ACL (n = 116), partial ACL tear (n = 103), and complete ACL tear (n = 117). In all groups, the femoral intercondylar notch width (INW), intercondylar distance (CD), notch width index (NWI), and intercondylar notch angle (INA), the angles between the tibial plateau and tibial spines (MPA and LPA), intercondylar eminence peak angle (IEA), and tibial slope angles (MSA and LSA) were measured. RESULTS: Femoral INW and NWI were significantly lower in patients with ACL pathology (p

This study aimed to investigate the morphological variations in the cross-sectional anatomy of the meniscus between similar-sized matched menisci. Knee MRI of 329 patients with intact menisci were retrospectively reviewed, and the meniscal length (ML), meniscal width (MW), and cross-sectional dimensions (meniscal height and width) of the anterior, posterior horns, and the corpus were measured. Patients with similar-sized menisci who had less than 1 mm difference in ML and MW were matched. 330 male-to-male medial menisci (MM), 623 male-to-male lateral menisci (LM), 82 female-to-female MM, 233 female-to-female LM, 176 cross-gender MM, and 265 cross-gender LM unique combination of ideally matched pairs (total: 1709) were generated. The disparity in the cross-sectional dimensions, absolute difference, and the paired percent differences was statistically analyzed. The ML and MW in all groups were statistically similar, with a predefined absolute difference of 1 mm both for ML and MW (paired percent difference

Age estimation is a crucial element of forensic medicine to assess the chronological age of living individuals without or lacking valid legal documentation. Methods used in practice are labor-intensive, subjective, and frequently comprise radiation exposure. Recently, also non-invasive methods using magnetic resonance imaging (MRI) have evaluated and confirmed a correlation between growth plate ossification in long bones and the chronological age of young subjects. However, automated and user-independent approaches are required to perform reliable assessments on large datasets. The aim of this study was to develop a fully automated and computer-based method for age estimation based on 3D knee MRIs using machine learning. The proposed solution is based on three parts: image-preprocessing, bone segmentation, and age estimation. A total of 185 coronal and 404 sagittal MR volumes from Caucasian male subjects in the age range of 13 and 21 years were available. The best result of the fivefold cross-validation was a mean absolute error of 0.67 ± 0.49 years in age regression and an accuracy of 90.9%, a sensitivity of 88.6%, and a specificity of 94.2% in classification (18-year age limit) using a combination of convolutional neural networks and tree-based machine learning algorithms. The potential of deep learning for age estimation is reflected in the results and can be further improved if it is trained on even larger and more diverse datasets.

Clinically measured Quadriceps angle (Q-angle) has low reliability. Measurement of angle between femoral shaft and patellar tendon (FSPT angle) on routine knee MRI was described in this study to represent the lateral vector forces of quadriceps mechanism. The cross-sectional study was designed to compare this angle between subjects with objective patellofemoral instability (PFI) versus those without PFI, to assess its reliability, and to assess its validity in terms of its ability to differentiate between PFI and non-PFI subjects using the “Receiver Operating Characteristic” (ROC) curve. MRI scans of 20 subjects with PFI and 20 without PFI were obtained. FSPT angle was measured in each MRI by three different raters. In addition, the clinical Q-angle was also measured in the control group. The FSPT angle was significantly higher in PFI group as compared with the non-PFI group (p

The aim of this study was to propose and validate a new six-item topographical classification of knee bone marrow lesions in coronal MRI images, to provide an easy-to-use aid to describe their location in a more reproducible and accurate way. This study was conducted in four phases. The first was to do a literature search for methods of describing bone marrow lesions in MRI of the knee. The second was creation of a six-area topographic classification of bone marrow lesions in coronal MRI of the knee. The third phase was selection of cases with bone marrow lesions on knee MRI performed in a single hospital between January of 2017 and December of 2018. The fourth phase was categorization of the bone marrow lesions’ location according to the new proposed classification by three independent examiners, two orthopedic surgeons and one radiologist. Patient’s demographic data and associated lesions were collected. The inter-observer and intra-observer reliability of the proposed classification was then calculated. MRI examination of 4000 patients were studied and in 520 patients a total of 666 bone marrow lesions were identified and their location classified using the new system. The inter-observer and intra-observer reliability analysis found a Fleiss’ Kappa value of 0.96 (0.95–0.97) and 0.97 (0.96–0.97), respectively, confirming the high reproducibility of the proposed classification. The proposed six-location classification of bone marrow lesions is highly reproducible and can help researchers develop studies and share information in a more accurate and reliable way. The correct classification of bone marrow lesions can lead to a more accurate description of this pathology and help clinicians to propose appropriate therapies for this group of patients. V.

To quantify the prevalence of complete tibial insertion of the biceps femoris tendon in patients presenting for knee MRI scans. Knee MRI scans over a 4-year period (2014–2018) were accessed at a tertiary referral centre and community-based private practice. A total of 433 scans were reviewed. 30 scans were excluded from the study due to repeat imaging or incomplete coverage of the biceps femoris tendon insertion. Appearances of the distal biceps tendon bony insertion were scrutinized on the remaining 403 scans. Each biceps femoris tendon insertion was classified into one of the four categories—complete fibular insertion, predominant fibular insertion, predominant tibial insertion and complete tibial insertion. Out of the final 403 scans included in the study, five cases of complete tibial insertion of the biceps femoris tendon were identified (just over 1% of the total population). 42 cases were identified as having predominant tibial insertion (10% of the total population). 113 cases had predominantly fibular insertion and 243 cases had complete fibular insertion. Complete anomalous insertion of the biceps femoris tendon on the anterolateral tibia is an uncommon entity. Such an attachment is found in approximately 1% of patients presenting for MRI evaluation of the knee.

Background Osteoarthritis (OA) of the knee joint is a common cause of chronic disability in older adults. During the past 10 years, the infrapatellar fat pad (IPFP) has emerged as a new player in the pathogenesis of knee OA. Its exact role in the pathogenesis of knee OA remains uncertain. While many studies focused on the detrimental effect of the chemical mediators released by IPFP and their role in the accentuation of the development of OA, only few studies elucidated the beneficial effect of IPFP maximal area as a local shock absorber protecting the adjacent articular structures from progressive damage. The aim of this study was to evaluate the relation between the IPFP maximal area and the prevalence of OA manifestations. We also studied the relation between the subcutaneous (SC) fat thicknesses on the medial aspect of the knee as a surrogate marker of body obesity and the IPFP area. Results A total of 216 knee scans for 188 adult patients (64 males and 124 females) who met the inclusion criteria were examined. They were between 45 and 66 years (mean 52.5 years). The mean IPFP area for all patients was 6.9 cm2 (± 1.6 SD) (ranged from 4.5 to 11 cm2). After adjustment for potential confounders, there was a significant negative association between IPFP area and radiographic manifestations of OA (osteophites, joint space narrowing, and grade of OA) (P value P value Conclusion In our study, we found supportive evidence that IPFP maximal area is associated with fewer osteoarthritic knee changes and less cartilage damage, suggesting that it plays a protective role against the development and progression of OA. Further large-scale clinical studies are awaited to confirm the obtained results. Based on our findings, it would be recommended to avoid IPFP resection during surgery in order to maintain its protective effect.

Background This work was conducted to assess the diagnostic efficiency of isotropic three-dimensional VISTA-fast spin echo versus standard two-dimensional fast spin echo at 1.5 T MRI, in the assessment of internal knee derangement in symptomatic patients, aiming to obtain similar diagnostic accuracy in a shorter time span, with reduction of partial volume artifacts by thin continuous sections. Results This was a non-randomized control study including 39 patients (32 male and 7 females, mean age 37 years old). A correlative study was done utilizing MRI standard 2D FSE (protocol A) versus 3D-VISTA-FSE (protocol B) for medial meniscus (MM) and lateral meniscus (LM), as well as anterior cruciate ligament ACL lesions, comparing the MRI results with the findings of arthroscopy as the gold standard. Both protocols depicted medial meniscus lesions with accuracy, specificity, and sensitivity (97.44%, 96.30%, and 100% respectively), lateral meniscus lesions with accuracy, specificity, and sensitivity (97.44%, 100%, and 50% respectively), and ACL lesions with accuracy, specificity, and sensitivity (100%, 100%, and 100% respectively), while there were no PCL lesions depicted through the study population. Comparing the time factor between both protocols revealed protocol A to consume 13.7 min, while protocol B consumed 6.6 min. Conclusion Three-dimensional isotropic VISTA-FSE sequence, although having similar accuracy in diagnosing cruciate and meniscal lesions as the standard sequences, facilitates thin-section data acquisition and multi-planar image reformation in standard and non-standard planes, without intersection gaps that are crucial for the detection and dissection of compound structures; also, it allows a shorter time span, which is more advantageous for patients, particularly the traumatized and emergency patients.

The studies of the relationship between anterior cruciate ligament (ACL) injury and notch size were in 2-D parameters in Han Chinese, the largest nation in the world, while few studies referred to the 3-D notch volume. The purpose of this study was to determine the differences in notch volume between individuals with and without ACL injuries and the optimal criterion value for abnormal notch volume and its sensitivity in predicting the risk of ACL injuries. Two hundred eighty individuals were included in this study, including 140 patients with non-contact sports ACL injuries only and 140 age- and gender-matched individuals without ACL injuries. Both groups underwent pre-operative knee MRI examinations and femoral notches were traced manually on 2-D MRI images, then 3-D notch volume was calculated. The notch volume was extremely smaller in the ACL-injured group than that in the control group (5.94 ± 1.35 versus 6.86 ± 1.61 cm3, P

To compare diagnostic performance of a 5-min knee MRI protocol to that of a standard knee MRI. One hundred 3 T (100 patients, mean 38.8 years) and 50 1.5 T (46 patients, mean 46.4 years) MRIs, consisting of 5 fast, 2D multi-planar fast-spin-echo (FSE) sequences and five standard multiplanar FSE sequences, from two academic centers (1/2015–1/2016), were retrospectively reviewed by four musculoskeletal radiologists. Agreement between fast and standard (interprotocol agreement) and between standard (intraprotocol agreement) readings for meniscal, ligamentous, chondral, and bone pathology was compared for interchangeability. Frequency of major findings, sensitivity, and specificity was also tested for each protocol. Interprotocol agreement using fast MRI was similar to intraprotocol agreement with standard MRI (83.0–99.5%), with no excess disagreement (≤ 1.2; 95% CI, −4.2 to 3.8%), across all structures. Frequency of major findings (1.1–22.4% across structures) on fast and standard MRI was not significantly different (p ≥ 0.215), except more ACL tears on fast MRI (p = 0.021) and more cartilage defects on standard MRI (p

To define the number and distribution of osteophytes (OPs) in bilateral knee MRI (magnetic resonance imaging) of patients with unilateral anterior cruciate ligament (ACL) rupture.Bilateral knee MRIs of 20 patients with unilateral ACL rupture and reconstruction were retrospectively analyzed for OPs. OPs were graded following the KOSS (knee OA scoring system) classification and their compartmental distribution was assessed following the WORMS (Whole-Organ Magnetic Resonance Imaging Score) classification.All examined knees revealed OPs. Knees with ACL rupture showed significant (p 0.001) higher total numbers of OPs (mean 11.6; SD ± 4.4) than knees with intact ACL (mean 5.1; SD ± 2.3). Knees with ACL rupture showed increased OP formation in all knee compartments with predominance of marginal OPs in the lateral femorotibial compartment especially on the tibia.Our results show that after knee injury with ACL rupture and reconstruction, all knee compartments were involved in post-traumatic increase of OP formation. The most affected compartment was the lateral femorotibial compartment on the tibial side.

Knee pain in young patients is a common indication for knee MRI. Many static and dynamic internal derangements of the patellofemoral joint in these patients lead to various secondary MRI findings. This article focuses on how to systematically approach, detect, and emphasize the importance of these findings in the diagnosis of patellofemoral tracking and impingement syndromes with relevant case examples.

This study provides the geometry of patella and patellar tendon measured on sagittal and axial magnetic resonance images of 172 knees (142 males, 30 females) of 163 subjects (135 males, 28 females) whose mean age was 26.7. The gender difference and the relationship with anthropometry were also given. As for patella, the longitudinal lengths of the whole and articulating surface were 44.6, 32.9 mm, and the thickness was 22.3 mm. The mediolateral width was 45.8 mm, and the central ridge was located 19.9 mm or 43% lateral from the medial border. As for patellar tendon, the longitudinal length was 40.2 mm. The widths of proximal and distal part were 30.3, and 24.0 mm. The thicknesses of proximal and distal part were 3.2, and 5.0 mm. The geometry of the patella and patellar tendon was larger in male than in female (P < 0.001). Anthropometry including weight, height, body mass index corresponds well with the thickness of patella but poorly with the length of patellar tendon. These data can provide useful information in the field of knee surgery and sports medicine.

Joint effusions are common after sports injuries. In a specific form they can be very accurate for the diagnosis of intraarticular fractures; however, assessment can be tricky. Several imaging means are compared which outline the advantages and disadvantages of each technique.

Background Magnetic resonance imaging (MRI) of the knee is the second most common MRI examination in Norway after head/brain MRI. Little has been published internationally on trends in the use of knee MRI after 1999. This study aimed to describe levels and trends in ambulant knee MRI utilisation in Norway 2002–2004 in relation to type of radiology service, geographic regions, number of MRI-scanners, patient age and gender, and type of referring health care provider. Methods We analysed administrative data on all claims for reimbursement of ambulant knee MRI performed in Norway in 2002, 2003 and 2004 and noted nominal reimbursement. We also recorded the referring health care provider from clinical requests of ambulant knee MRI done consecutively during two months in 2004 at one private institute and three hospitals. Number of MRI-scanners was given by manufacturers and radiology services. Results In Norway, the rate of knee MRI claims for 2004 was 15.6 per 1000 persons. This rate was 74% higher in East than in North region (18.4 vs. 10.6), slightly higher for men than women (16.4 vs. 14.7) and highest for ages 50–59 years (29.0) and 60–69 years (21.2). Most claims (76% for 2004) came from private radiology services. In 2004, the referring health care provider was a general practitioner in 63% of claims (unspecified in 24%) and in 83.5% (394/472) of clinical requests. From 2002 to 2004, the rate of knee MRI claims increased 64%. In the age group 50 years or above the increase was 86%. Rate of MRI-scanners increased 43% to 21 scanners per million persons in 2004. Reimbursement for knee MRI claims (nominal value) increased 80% to 70 million Norwegian kroner in 2004. Conclusion Ambulant knee MRI utilisation in Norway increases rapidly especially for patients over 50, and shows large geographic differences. Evaluation of clinical outcomes of this activity is needed together with clinical guidelines for use of knee MRI.

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.