Magnetic Resonance Imaging Magnet Research Articles

A simulation study of MR-guided proton therapy system using iron-yoked superconducting open MRI: a conceptual study.

Radiotherapy platforms integrated with magnetic resonance imaging (MRI) have been significantly successful and widely used in X-ray therapy over the previous decade. MRI provides greater soft-tissue contrast than conventional X-ray techniques, which enables more precise radiotherapy with on-couch adaptive treatment planning and direct tracking of moving tumors. The integration of MRI into a proton beam irradiation system (PBS) is still in the research stage. However, this could be beneficial as proton therapy is more sensitive to anatomical changes and organ motion. In this simulation study, we considered the integration of PBS into the 0.3-T superconducting open MRI system. Our proposed design involves proton beams traversing a hole at the center of the iron yoke, which allows for a reduced fringe field in the irradiation nozzle while maintaining a large proton scan field of the current PBS. The shape of the bipolar MRI magnets was derived to achieve a large MRI field-of-view. To monitor the beam position and size accurately while maintaining a small beam size, the beam monitor installation was redesigned from the current system. The feasibility of this system was then demonstrated by the treatment plan quality, which showed that the magnetic field did not deteriorate the plan quality from that without the magnetic field for both a rectangular target and a prostate case. Although numerous challenges remain before the proposed simulation model can be implemented in a clinical setting, the presented conceptual design could assist in the initial design for the realization of the MR-guided proton therapy.

Implementing a two-stage, shim field-calibrated superconducting shimming method on a 7 T cryogen-free small animal MRI magnet

Ultrahigh field systems (≥ 7 T) can increase the signal-to-noise ratio of magnetic resonance imaging (MRI), improving imaging performance compared to systems with lower fields. However, these enhancements heavily rely on a high B0 magnetic field homogeneity level, which can be achieved through superconducting shimming. This paper presents a novel two-stage superconducting shimming method designed to achieve precise shimming for a 7 T MRI superconducting magnet. In the initial stage, detailed measurements and fittings were conducted to determine the current polarity and the axial or circumferential positions of the shim fields. Subsequently, an optimization strategy was implemented to determine the optimal shim currents with a flexible target field. The second stage involves an iterative process to fine-tune the current of a specific shim coil, identified as having the most significant impact on field homogeneity. The overall fitness of 99.5% underscores the precision in determining the current polarity and position of the shim fields. Significantly, the calibrated shim system substantially improves the peak-to-peak and Root Mean Square Error (RMSE) field homogeneities from 107.42 ppm and 37.00 ppm to 11.12 ppm and 3.26 ppm, respectively, representing improvements of 89.65% and 91.19%. Furthermore, the simulation results of the fine-tuning stage demonstrate additional enhancements in peak-to-peak field homogeneity, to 9.9 ppm by reducing the current of the Z2 shim coil by 51.3 mA. Additionally, the shimmed magnetic field exhibited high time stability, with a maximum variation of only 27 µT observed within 48 h. Thus, the proposed two-stage superconducting shimming framework effectively addresses the challenge of imperfect B0 magnetic fields, enhancing peak-to-peak and RMSE field homogeneity. The stepwise optimized approach also mitigates deviations caused by shim-to-shim coupling, demonstrating its efficacy in achieving precise shimming in ultrahigh-field MRI systems.

A hybrid, nonlinear programming approach for optimizing passive shimming in MRI.

In magnetic resonance imaging (MRI), maintaining a highly uniform main magnetic field (B0) is essential for producing detailed images of human anatomy. Passive shimming (PS) is a technique used to enhance B0 uniformity by strategically arranging shimming iron pieces inside the magnet bore. Traditionally, PS optimization has been implemented using linear programming (LP), posing challenges in balancing field quality with the quantity of iron used for shimming. In this work, we aimed to improve the efficacy of passive shimming that has the advantages of balancing field quality, iron usage, and harmonics in an optimal manner and leads to a smoother field profile. This study introduces a hybrid algorithm that combines particle swarm optimization with sequential quadratic programming (PSO-SQP) to enhance shimming performance. Additionally, a regularization method is employed to reduce the iron pieces' weight effectively. The simulation study demonstrated that the magnetic field was improved from 462 to 3.6ppm, utilizing merely 1.2kg of iron in a 40cm diameter spherical volume (DSV) of a 7T MRI magnet. Compared to traditional optimization techniques, this method notably enhanced magnetic field uniformity by 96.7% and reduced the iron weight requirement by 81.8%. The results indicated that the proposed method is expected to be effective for passive shimming.

Brain MRI sequence and view plane identification using deep learning.

Brain magnetic resonance imaging (MRI) scans are available in a wide variety of sequences, view planes, and magnet strengths. A necessary preprocessing step for any automated diagnosis is to identify the MRI sequence, view plane, and magnet strength of the acquired image. Automatic identification of the MRI sequence can be useful in labeling massive online datasets used by data scientists in the design and development of computer aided diagnosis (CAD) tools. This paper presents a deep learning (DL) approach for brain MRI sequence and view plane identification using scans of different data types as input. A 12-class classification system is presented for commonly used MRI scans, including T1, T2-weighted, proton density (PD), fluid attenuated inversion recovery (FLAIR) sequences in axial, coronal and sagittal view planes. Multiple online publicly available datasets have been used to train the system, with multiple infrastructures. MobileNet-v2 offers an adequate performance accuracy of 99.76% with unprocessed MRI scans and a comparable accuracy with skull-stripped scans and has been deployed in a tool for public use. The tool has been tested on unseen data from online and hospital sources with a satisfactory performance accuracy of 99.84 and 86.49%, respectively.

Utility of Adult-Based Discoid Lateral Meniscus Diagnostic Criteria in a Pediatric Population.

Commonly cited discoid lateral meniscus (DLM) imaging definitions are based on adult magnetic resonance imaging (MRI) measurements. This pathology commonly presents in pediatric populations; however, whether accepted adult measurements reliably apply to children and adolescents is unknown. This purposes of the study were to determine (1) the utility of applying adult-accepted MRI definitions of DLM to pediatric patients, (2) whether sex differences affect the applicability of the criteria, and (3) whether MRI magnet strength and/or tear presence affect MRI measurements for diagnosing DLM in pediatric patients. It was hypothesized that MRI criteria for DLM would be similar in adults and pediatric patients. Case series; Level of evidence, 4. A total of 100 consecutive MRIs from pediatric patients with DLM were evaluated, with 91 scans included. Two study authors independently reviewed the MRIs, evaluating meniscal height and width on sagittal and coronal images, "bow tie signs" on sagittal images, tibial sagittal and coronal width, and tear presence. For analysis, MRI magnet strength was dichotomized into high (>1.5 T) and low (<1.5 T) groups. The mean age of the patients at MRI evaluation was 12.3 ± 3.4 years; 51% of the patients were male, and 56% of the scans were of left knees. Included patients with DLM showed a mean of 3.68 bow tie signs, a sagittal total anterior to posterior meniscal width/tibial width ratio of 73%, a coronal meniscal width/tibial width ratio of 30%, and a coronal, transverse width of the lateral meniscus at the midportion of the meniscal body of 20.6 ± 7.7 mm. The MRI tesla strength of the images included in this study ranged from 0.3 to 3. It was determined that high- versus low-resolution MRI scans did not affect the inter- or intraobserver reliability of the MRI measurments (P > .05). However, several measurements showed improved intraclass correlation coefficients with increased tesla strength. This study confirms that pediatric patients with DLM, diagnosed by board-certified pediatric sports medicine orthopaedic surgeons, have measurements on MRI consistent with adult DLM diagnostic criteria. This finding held true regardless of sex or MRI tesla strength. Pediatric patients with DLM had >3 bow tie signs, >70% sagittal tibial plateau coverage, >14 mm coronal width, and >20% coronal tibial plateau coverage on MRI.

Ultrasonography, computed tomography and magnetic resonance imaging of the dromedary camel distal limbs

BackgroundLameness associated with the distal limb region in dromedary camels is quiet prevalent. The diagnosis of lameness relies on a comprehensive orthopedic examination conjugated with an appropriate imaging modality to achieve a decisive diagnosis. Using of modern imaging tools provoked a significant breakthrough in the diagnosis of lameness. Ultrasonography (US) is widely established in dromedaries, whereas computed tomography (CT) and magnetic resonance imaging (MRI) are gaining popularity. CT provides a considerably higher bone detail than any other imaging modality. US and MRI continue to be the best options for soft tissue imaging. A truthful assessment of the clinical US, CT and MRI images dictates a comprehensive familiarity with the standard US, CT and MRI tissue deviations. Accordingly, our purposes were to present a full MRI protocol for investigating the dromedary camel distal limbs as well as comparing and illustrating the merits of using MRI, CT and US for evaluation of the front and hind distal limbs in 10 healthy lameness free dromedary camel cadavers. The limbs were scanned via a high-field 1.5 Tesla MRI magnet and a multi-detector CT scanner then subjected to a systematic US examination in both longitudinal and transverse planes. The obtained MRI, CT and US images were evaluated, correlated and compared.ResultsCT and MRI eliminated the structural superimposition in the dromedary camel distal limbs and afforded assessment of minute ligamentous and tendentious structures that were inaccessible by US including the axial collateral ligaments, ligaments supporting the proximal sesamoid bones and the palmar/plantar aspects of the inter-phalangeal joints. US and MRI were appreciated for the assessment of the articular cartilage that was not visible on the plain CT images.ConclusionsCT and MRI accurately identified and characterized bones and soft tissues constituting the dromedary camel distal limbs. US was appreciated for assessment of soft tissues, articular cartilage and bone contours. CT and MRI may be considered when US results are inconclusive or to evaluate the unreachable parts of the camel distal limbs. Images presented in this study could be used as a reference standard for evaluating dromedary camel distal limb diseases.

Persistent MgB2 joints for react and wind magnets

Ultra-low resistance joints are a key technology enabling superconducting magnets to operate in persistent mode and to achieve the temporal stability required for nuclear magnetic resonance and magnetic resonance imaging (MRI) applications. High performance superconducting joints are manufactured routinely for Nb–Ti and Nb3Sn magnets, but technologies for joining other technological superconductors are still in the early stages of development. Here we report the use of a simple cold pressing and heat treatment procedure to fabricate persistent MgB2 joints with resistance values <10−12 Ω between MgB2 wires that have already undergone the full wire reaction process. Trapped persistent currents of 172 A and 160 A were achieved under self-field and 1 T background field conditions respectively at a temperature of 20 K. This corresponds to a critical current ratio of 78% under these conditions, outperforming previously reported joints using fully reacted MgB2 wire. These findings are relevant for the development of commercial MRI magnets with MgB2 wires utilizing react and wind methods.

Passive shimming for the 9.4 T whole-body MRI superconducting magnet

A superconducting magnet with a warm-bore size of 800 mm and a center magnetic field of 9.4 T for the whole-body magnetic resonance imaging (MRI) system was developed in IEECAS, China. To achieve a highly homogeneous magnetic field over the 400 mm diameter of spherical volume (DSV), both active shimming and passive shimming techniques were employed. This paper mainly focuses on the implementation of passive shimming for the 9.4 T MRI magnet system. After four iterations, we were able to achieve peak-to-peak and root mean square field homogeneities over the DSV at 3.05 and 0.94 ppm, respectively. In addition, this paper analyzes the electromagnetic forces and system errors of passive shimming for ultra-high fields, providing valuable insights into MRI magnet engineering.

A novel joint-less coil: promising unprecedented magnetic field stability to solve the persistent current mode issue in 2G-HTS magnet application

Closed coils fabricated using second generation high temperature superconducting (2G-HTS) coated conductors (CCs) are promising for superconducting magnets, which operating in persistent current mode (PCM) such as magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) systems. However, the fabrication and application of superconducting joints for 2G-HTS CCs still pose a significant challenge. This paper reports a PCM joint-less 2G-HTS coil for capturing magnetic fields, which is called ‘Four Pancake Coil (FPC)’. A novel winding method was developed to form four pancake structure and effectively solved the closed-loop problem of 2G-HTS magnets. Meanwhile, the FPCs generated a 70.4 mT central magnetic field at 77 K and lasted for 57 d with a magnetic field drift rate of only 0.065 ppm h−1, which can satisfy the requirements of MRI magnets. In addition to the closed-loop characteristics of the FPC, the stacked magnet also provides expandability and ease of maintenance exchange. These advantages make it highly promising for the development of closed-loop 2G-HTS magnets.

Gradient coil design with enhanced shielding constraint for a cryogen-free superconducting MRI system

The relatively fragile low-temperature stability of cryogen-free superconducting magnetic resonance imaging (MRI) magnets requires the careful management of exogenous heat sources. A strongly shielded gradient magnetic field is important for the optimal operation of cryogen-free MRI systems. In this study, we present an enhanced shielding method incorporating a regionalized stray field constraining strategy. By optimizing the constraint parameters, we could develop engineering-feasible gradient coil schemes without increasing system complexity but with the stray field intensity reduced by half. In real measurement in an integrated MRI system, the developed gradient assembly demonstrated good performance and supported to output images of excellent quality. Our findings suggested that the proposed method could potentially form a useful design paradigm for cryogen-free MRI magnets.

Conceptual Design of a Portable, Solid-Nitrogen-Cooled 0.5-T/560-mm Point-of-Care MRI Magnet.

We describe the conceptual design of a portable, liquid-helium-free, all-REBCO, 0.5-T/560-mm point-of-care magnetic resonance imaging (MRI) magnet. It is free from an external power supply and a refrigeration system during operation. In our portable MRI magnet, we use a detachable "cryocirculator" that circulates, in a closed circuit, cold working fluid, and most importantly for portability, it can be readily coupled to or decoupled from the magnet, in contrast, a conventional cryocooler is mechanically attached to the magnet. Another unique feature of our system is a volume of solid nitrogen (SN2) in the cold chamber that adds enough thermal mass to the magnet in the 30-36-K operating temperature range, enabling it to maintain its field over a period of, for this system, ≥10 hours, plenty enough for this portable MRI system, uncoupled from its cryocirculator, to perform its mission before it needs recooling.

On the passive shimming of a 7 T whole-body MRI superconducting magnet: Implementation with minimized ferromagnetic materials usage and operable magnetic force control.

Magnetic field shimming of the magnet is a routine practice in a magnetic resonance imaging (MRI) system. For clinically-used 1.5 T or 3 T MRI superconducting magnets, it is generally straightforward to achieve desired magnetic field uniformity with the passive shim technique. In comparison, superconducting shims with higher shimming efficiency are usually introduced in combination with passive shimming to satisfy the higher magnetic field uniformity requirement for ultrahigh field magnets (≥7 Tesla). However, superconducting shim usually involves a complex winding structure and low-temperature environment, bringing considerable engineering challenges and extra costs in practice. In this study, we aimed to improve the passive shimming method that can incorporate the unique electromagnetic properties of ultrahigh-field MRI magnets and is thus more effective for field corrections at 7T and above. In this work, we propose a dedicated passive shimming strategy for a 7 T whole-body MRI superconducting magnet. In this method, the iron usage and magnetic force due to the iron-field interaction are strictly managed to ensure a shim tray insert is operable by manpower (without specially designed tools). To validate the proposed shimming strategy, a shimming experiment was implemented on a 7 T/800mm superconducting magnet. Alternating with the odd and even shim trays in our two-round operation, the magnetic field inhomogeneity was successfully corrected from 85.36 to 7.91ppm, achieving the magnetic field quality elevation of more than one order of magnitude. The experimental results indicated that the proposed electromagnetic technology is expected to be effective for developing ultrahigh-field MRI instruments.

THE ROLE OF OFFICE-BASED NEEDLE ARTHROSCOPY IN THE DIAGNOSIS OF INTRA-ARTICULAR KNEE SYMPTOMS: A CASE REPORT

Anterior cruciate ligament (ACL) tears are serious knee injuries, whether partial or total. ACL injuries are most typically diagnosed in the clinic settings using a combination of a detailed history, physical examination and corroborated with an appropriate imaging modality. Magnetic resonance imaging (MRI) is highly sensitive for identifying intra-articular knee pathology. This combination has been demonstrated to be effective and non-invasive in diagnosing ACL injury. The reliability of MRI for diagnostic purposes, on the other hand, is not always ideal. This might be due to various factors, including low-quality MRI magnets, post-surgical tissue changes, metallic artifacts, patient movement during procedure, and static rather than dynamic structural evaluation. Nevertheless, office-based diagnostic arthroscopy offers an alternative to imaging modalities by allowing clinicians to visualize large joints safely, painless, high-quality images, and time-efficient approaches. Furthermore, the risk of major and minor complications of office-based diagnostic arthroscopy is comparable to or lower than any standard office-based injection. This is the first office-based needle arthroscopy (OBNA) performed in Malaysia to evaluate intra-articular knee symptoms. Thus, we aim to understand and overview OBNA to identify intra-articular knee pathology by reporting this case report.

Systematic analysis of the quench process performance and simulation of the 9.4 T-800 mm whole-body MRI magnet

In 2021, the Institute of Electrical Engineering, Chinese Academy of Sciences successfully reached 9.4 T in a whole-body magnetic resonance imaging (MRI) superconducting magnet with an inner diameter of 800 mm. In this study, a systematic analysis of both the real quench protection performance and a simulation are reported. The four successful quench protections during the entire energization process proved the feasibility of the ‘in-out-in’ quench protection protocol for a 9.4 T-800 mm superconducting magnet. The quench trigger sequence was shown to be adjusted by changing the heater thickness, which demonstrates the flexibility of the ‘in-out-in’ quench protection protocol to fit a different MRI magnet design. The high accuracy of the quench protection simulation method and code was confirmed through comparison of the simulation results with the real performance. Moreover, the limitations of the current quench protection and reference value to other MRI magnets were discussed. It is believed that this study will be useful to other research groups and promote the development of an extremely high-field whole-body MRI system.

Design, construction and performance testing of a 1.5 T cryogen-free low-temperature superconductor whole-body MRI magnet

This work describes the design, construction and testing of a 1.5 T cryogen-free low-temperature superconductor niobium–titanium whole-body magnet with a bore diameter of 850 mm that is suitable for clinical magnetic resonance imaging (MRI) applications. The magnet is actively shielded and passively shimmed to achieve confinement within a 0.5 mT stray magnetic field at 2.5/4 m radial/axial positions and 12.1 ppm field inhomogeneity over a 45 mm diameter of spherical volume. The magnet is conductively refrigerated using a two-stage Gifford–McMahon cryocooler and can be maintained at a steady temperature below 5.7 K during MRI scanning. The MRI scanner assembled with the designed cryogen-free magnet demonstrated stable performance and provided MRI images with good quality and high contrast.

Conceptual Design and Sensitivity Analysis of MRI Magnets From REBCO HTS Tapes

An actively shielded wide-bore magnet system has been designed for magnetic resonance imaging. The gradient-based optimization solver of COMSOL Multiphysics has been used to obtain an optimum geometrical arrangement of symmetrical electromagnets in the magnetic resonance imaging (MRI) system. To generate a high and homogeneous magnetic field, we employed a second-generation rare-earth barium-copper-oxide (REBCO) high-temperature superconductor (HTS), which was wound into 10 double pancake coils (DPC). The dimensions of the DPC sets have been chosen considering the size of REBCO HTS tapes, and the optimized design solution provides magnetic field, stray field, and current passing through the HTS tapes on each DPC set. The design details of a 1.5 T actively shielded magnet as well as the sensitivity analysis of the inhomogeneity, stray field, and currents with respect to coil positions have been presented. Optimum parameters for various designs are listed. The inhomogeneity of 1.23 ppm in the 200 mm diameter of spherical volume (DSV) and a stray field of as low as 0.05 G outside of the 5 m distance were achieved. Additionally, a low peak field of 2.40 T in DPC sets has been accomplished.

An Experimental Study on the Passive Shimming in the 0.5 T Superconducting MRI Magnet

For the superconducting magnetic resonance imaging (MRI) magnet, passive shimming technique in low field is more complicated than that in high field, due to the unsaturated magnetization of the used shim pieces and other issues, such as the oversized minimum shim piece and insufficient accuracy. For common problems of the MRI magnets and the special problems caused by low field, an experimental study was carried out on the 0.5 T superconducting magnets by adopting some improved strategies for passive shimming of low field in this article. Three magnets of the same type were used as experimental objects, and the proven measures were proposed to improve the problems of the unsaturated magnetization, shim piece specification, and position difference. The experimental results showed that the passive shimming reliably enables the static magnetic field of the 0.5 T MRI magnet to achieve the required homogeneity, which have practicality and reference value for the fabrication and shimming of the low-field MRI magnet.

Temperature Dependence of Optimal Shape and DC Current Transport Characteristics of 3 T Whole Body REBCO MRI Magnet

This paper reports the optimum design results of REBCO high-temperature superconducting magnets for 3 T-whole-body magnetic resonance imaging (MRI). The REBCO magnet consists of a main coil, compensation coil, and shield coil, and optimum design is carried out using an immunogenetic algorithm. A magnetic field uniformity of 20 ppm was observed in the uniform sphere inside the coil, and a 5-gauss region of 2.67 m in radial length and 4.50 m in axial length was realized. The local magnetic field vector distribution of the designed coil was also calculated for the designed magnet using electromagnetic field analysis, and the local voltage was obtained using the magnetic field/temperature dependence of the electric field vs. current density properties evaluated with the REBCO short sample. Then, the voltage vs. current characteristics of the magnet were evaluated by adding it over the entire coil length. Defining the current load factor (operating current/critical current) of the designed magnet using the above analysis results makes it possible to clarify the relationship between the operating current, optimized magnet shape, and required wire length for the operating temperature. In particular, we found that the required HTS tape length and transport current have a simple linear relationship in the operating temperature range below approximately 50 K.

Relation between constituent material fraction in multifilamentary MgB2 wires and requirements for MRI magnets

Magnetic resonance imaging (MRI) occupies the largest segment of the commercial applications of superconductivity. The NbTi wire is typically applied to MRI magnets and fulfils their strict requirements. On the other hand, the dramatically large energy margin in the MgB2 wire is attractive for liquid helium-saving MRI magnets. However, there are many types of cross-sections in the MgB2 wires. This makes it difficult to analyse the applicability of the MgB2 wires to the MRI magnets systematically. This paper focuses on the in situ MgB2 wires with an iron matrix and a Monel reinforced member. Multiple evaluations are conducted for several types of MgB2 wires, and their applicability to the MRI magnets is discussed. Because the critical current density of the superconducting filaments does not largely depend on the cross-section of the wires, the engineering critical current density (J e) is roughly proportional to the superconducting fraction (λ sc). The acceptable bending strain of the heat-treated wires increases with the Monel fraction and is in the range of 0.3%–0.65%, which is larger than the value required for coil winding of the MRI magnets. Two types of protection approaches of the magnet are considered. One is an active protection. This approach requires a large fraction of the copper stabilizer in the cross-section of the wire and relatively reduces λ sc and J e. The other is the avoidance of quenches over the product lifetime using quick ramp-down of the magnet for unfortunate events, such as cooling system failure and emergency rundown. This approach requires no copper stabilizer and increases λ sc and J e thus widens the acceptable operational temperature range. The cross-section of the MgB2 wire can be designed with a certain level of freedom depending on its functional requirements.

Magnetic Resonance Imaging of Lateral Meniscus Root Tears in the Pediatric and Adolescent Knee: Is the Diagnosis Missed, Mentioned, or Made?

Background:Failure to address meniscus root tears may place undue loads on anterior cruciate ligament (ACL) reconstructive surgery in the adult population. Because the intraoperative management of lateral meniscus posterior root tears (LMPRTs) may diverge from standard meniscal work and requires specialty items, preoperative diagnosis may be advantageous.Purpose:To evaluate the reliability of radiologist interpretations of preoperative knee magnetic resonance imaging (MRI) scans of lateral meniscus root pathology in a mixed pediatric and adolescent population.Study Design:Cohort study (diagnosis); Level of evidence, 2.Methods:A retrospective review of medical records was performed to identify patients younger than 18 years with an arthroscopically confirmed LMPRT who underwent knee arthroscopy between March 1, 2010, and April 1, 2020. Arthroscopic findings were compared with the reading radiologist’s preoperative MRI interpretations, and patients were stratified into 2 groups: (1) LMPRT diagnosis made preoperatively or (2) diagnosis missed or only mentioned to describe pathology nonspecific to the root. Variables such as body mass index (BMI), open physes, time from injury to MRI, time from MRI to surgery, MRI magnet field strength, musculoskeletal radiologist designation, insurance type, and tear grade were assessed between groups.Results:Overall, 1116 knee arthroscopies were performed, with 49 LMPRTs found; all 49 LMRPTs were found concomitantly with ACL tears (49/535; 9.2%). The average patient age was 15.97 years (range, 11.52-17.97 years). There were 50 MRI scans for 49 patients. An LMPRT was diagnosed based on preoperative MRI scans in 12 of these 50 scans (24%) and mentioned or missed in 38 of the 50 scans (76%). No significant difference was seen between the diagnosis-made versus diagnosis-mentioned/missed groups in BMI, skeletal maturity, time from injury to MRI, time from MRI to surgery, MRI magnet strength, fellowship training of the reading radiologist, tear grade, or insurance type.Conclusion:In 76% of patients, a definitive diagnosis of LMPRT was not made on preoperative MRI scans. Notably, all LMPRTs found intraoperatively were found concomitantly with ACL tears.