Diagnostic equivalence of conventional and fast spin echo magnetic resonance imaging of the anterior cruciate ligament of the knee

Accuracy of MRI diagnosis of internal derangement of the knee in a non-specialized tertiary level referral teaching hospital

This study was designed to assess the accuracy of knee MRI examinations carried out in a general tertiary referral hospital without a musculoskeletal fellowship trained radiologist. The study included all patients who had undergone a knee arthroscopy carried out within a 2-year period and who had had a prior MRI knee examination, where both were carried out at this institution. The accuracy of the MRI knee examination was determined by correlation to the arthroscopy report. The accuracy for diagnosis of meniscal and cartilage injuries, in this setting, was found to be similar to a published meta-analysis of previous studies correlating knee MRI and arthroscopy. The overall accuracy of this study was better than the previous similar study. However, the accuracy for diagnosing ACL injuries was lower than in the meta-analysis. The potential reasons for this and other sources of error are discussed.

MR imaging of acute anterior cruciate ligament injuries

MRI of the knee has become an indispensable clinical tool in the management of chronic knee conditions. MRI for acute knee injuries is less well established but is becoming increasingly prevalent. MRI in acute ACL injuries is particularly useful for identifying associated injuries that will influence the early management of the patient. The aim of this paper is to describe the MRI findings of acute ACL tears, their commonly associated, and less common but serious associated injuries. Where available, the evidence for the sensitivity and specificity of these MRI features is presented. The contribution of these MRI findings to the management of the patient is discussed.

3-T MR imaging of partial ACL tears: a cadaver study

Magnetic resonance imaging (MRI) is the most commonly used diagnostic imaging procedure for suspected injuries to the anterior cruciate ligament (ACL). However, MRI has less utility for the evaluation of partial ACL tears. The goal of this study was to evaluate the possibility of distinguishing partial ACL tears applying the double bundle concept by dividing the ACL anatomy in the anteromedial (AM) and posterolateral bundle (PL). Six human cadaver knees were used in this laboratory study. The protocol consisted of sagittal, oblique coronal, and oblique sagittal proton-density-weighted fast spin echo sequences. After MRI the AM and the PL bundle were severed to mimic different partial ACL rupture patterns. MRI scanning of each knee was repeated, to record the quantitative parameters tilt and ACL angles and discontinuity as a nonquantitative parameter. Three orthopaedic surgeons and two radiologists were enlisted as blinded observers to evaluate the images. The transection patterns could be differentiated by evaluating discontinuity both in the paracoronal and in the sagittal plane. Evaluating the transection patterns, the AM bundle reached a better result in both planes compared to the PL bundle and the paracoronal plane had a better result in assessing the transection patterns compared to the sagittal plane for the PL bundle. Partial ACL transections could predictably be recognized on oblique sagittal and oblique coronal planes utilizing 3-T MRI technology. This concept allows a more precise description of ACL rupture patterns and might lead to a more distinctive approach for reconstructive surgery. The presurgical planning could be improved by applying a treatment algorithm based on a description of each bundle as intact or ruptured, leading to a reconstruction of the torn and a preservation of the intact bundle.

2D and 3D 3-tesla magnetic resonance imaging of the double bundle structure in anterior cruciate ligament anatomy

For anterior cruciate ligament (ACL) surgery using the anatomic approach of the double bundle concept it is helpful to describe the anteromedial (AM) and posterolateral (PL) bundle using Magnetic Resonance Imaging (MRI), since this is the most important preoperative parameter next to the physical examination. The aim of this study was to distinguish both bundles in MRI. In a prospective study we evaluated the double bundle structure in ACL anatomy with a 3-T ultra-high-field strength MR imaging of cadaver knees, which allows faster imaging times, increased resolution and increased signal-to-noise ratio. Using oblique sagittal and oblique coronal planes, we were able to distinguish the double bundle structure in each knee. The following arthroscopic evaluation of the knees confirmed our MRI findings. Our study demonstrates the possibility of distinguishing the two bundles in the native ACL with 3T MRI. Following examinations must study the value for clinical application by describing different rupture patterns of the bundles and correlating this to arthroscopy. It would be advantageous to know the rupture pattern in advance. Presurgical planning could be improved by reconstructing only the torn and preserving the intact bundle.

3T MR Imaging of the Musculoskeletal System (Part II): Clinical Applications

The gain in SNR that is afforded by 3T MR imaging systems has tremendous clinical applications in the musculoskeletal system. The potential for demonstrating and enhancing the visibility of normal osseous, tendinous, cartilaginous, and ligamentous structures is exciting. Furthermore, harnessing this added signal to increase spatial resolution may improve our diagnostic abilities in various joints dramatically. Radiologists have enjoyed great success in assessing joint disease with current MR imaging field strengths; however, many intrinsic joint structures remain poorly evaluated, which leads to a golden opportunity for 3T MR imaging. The articular cartilage of the knee, the glenoid labrum of the shoulder, the intrinsic ligaments and TFC of the wrist, the collateral ligaments of the elbow, the labrum and articular cartilage of the hip, and the collateral ligaments of the ankle have been evaluated suboptimally on 1 .5T systems using routine nonarthrographic MR images. Because of the enhanced SNR, the higher spatial resolution, and the greater CNR of intrinsic joint structures at higher field strengths, 3T MR imaging has the potential to improve diagnostic abilities in the musculoskeletal system vastly, which translates into better patient care and management. The author's 2 years of clinical experience with musculoskeletal MR imaging on 3T systems has met and exceeded his expectations, and has bolstered the confidence of his orthopedic surgeons in his diagnoses. As coil technology advances and as the use of parallel imaging becomes more available in the extremities, the author expects to see even more dramatic improvements in image quality.