Jenny T. Bencardino

Glenohumeral instability: evaluation using MR arthrography of the shoulder

Abstract In the setting of glenohumeral instability or when internal derangement of the shoulder joint is suspected, MR arthrography has been demonstrated to be an accurate diagnostic imaging technique. Knowledge of the complex anatomy of the shoulder and its variations is essential in order to maximize diagnostic accuracy.

Quantitative magnetic resonance imaging evidence of synovial proliferation is associated with radiographic severity of knee osteoarthritis.

OBJECTIVE To evaluate the relationships between both quantitative and semiquantitative assessments of the degree of knee synovitis on 3T magnetic resonance imaging (MRI) and the severity of knee osteoarthritis (OA) on radiography. METHODS Fifty-eight patients with knee OA underwent nonfluoroscopic fixed-flexion knee radiography. In addition, dynamic contrast-enhanced 3T MRI of the knees was performed, before and after gadolinium administration, to quantify synovial membrane volume (SV) as a measure of synovial proliferation (expressed as the quantitative SV), and semiquantitative measures of synovitis were also applied using both contrast-enhanced and unenhanced images. Two radiologists scored the knee radiographs using the Osteoarthritis Research Society International atlas; interreader agreement was assessed using kappa statistics and concordance correlation coefficients. Multiple linear and logistic regression analyses were used to assess associations among variables, while controlling for the effects of age, body mass index, sex, and meniscal extrusion. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for measures of disease activity. RESULTS The Kellgren/Lawrence (K/L) grade of radiographic knee OA severity (β=0.78), the diseased compartment joint space width (dcJSW) (β=-0.22), and the diseased compartment joint space narrowing (dcJSN) score (β=0.53) were each significantly associated with the quantitative SV (P=0.0001, P=0.0003, and P=0.0001, respectively). Furthermore, the quantitative SV strongly correlated with the total volume of subchondral bone marrow lesions (BMLs) (β=0.22, P=0.0003). The K/L grade, dcJSW, and dcJSN score were each significantly associated with the semiquantitative Boston Leeds Osteoarthritis Knee Score (BLOKS) for the extent of infrapatellar synovitis (OR 9.05 [95% CI 1.94, 42.3] for K/L grade; OR 0.75 [95% CI 0.54, 1.03] for dcJSW; and OR 2.22 [95% CI 1.15, 4.31] for dcJSN score) and extent of joint effusion (OR 5.75 [95% CI 1.23, 26.8] for K/L grade; OR 0.70 [95% CI 0.50, 0.98] for dcJSW; and OR 1.96 [95% CI 1.02, 3.74] for dcJSN score). In addition, the semiquantitative synovitis grade on contrast-enhanced MRI was significantly associated with the K/L grade (β=0.036, P=0.0040) and dcJSN score (β=0.015, P=0.0266), and also significantly associated with the BLOKS synovitis score. CONCLUSION Synovitis is a characteristic feature of advancing knee OA and is significantly associated with the K/L grade, JSW, JSN score, and total volume of BMLs on radiographs. Furthermore, BLOKS scoring of synovitis on unenhanced MRI is associated with measurements of synovitis on contrast-enhanced MRI.

Chondrocalcinosis of the hyaline cartilage of the knee: MRI manifestations

Abstract Purpose. To determine the ability of MRI to detect the presence of crystals of calcium pyrophosphate in the articular cartilage of the knee. Design and patients. The MR studies of 12 knees (11 cases) were reviewed retrospectively and correlated with radiographs (12 cases) and the findings at arthroscopy (2 cases) and surgery (1 case). A total of 72 articular surfaces were evaluated. Radiographic, surgical or arthroscopic demonstration of chondrocalcinosis was used as the gold standard. Additionally, two fragments of the knee of a patient who underwent total knee replacement and demonstrated extensive chondrocalcinosis were studied with radiography and MRI using spin-echo T1-, T2- and proton-density-weighted images as well as two- and three-dimensional fat saturation (2D and 3D Fat Sat) gradient recalled echo (GRE) and STIR sequences. Results. MRI revealed multiple hypointense foci within the articular cartilage in 34 articular surfaces, better shown on 2D and 3D GRE sequences. Radiographs showed 12 articular surfaces with chondrocalcinosis. In three cases with arthroscopic or surgical correlation, MRI demonstrated more diffuse involvement of the articular cartilage than did the radiographs. The 3D Fat Sat GRE sequences were the best for demonstrating articular calcification in vitro. In no case was meniscal calcification identified with MRI. Hyperintense halos around some of the calcifications were seen on the MR images. Conclusion. MRI can depict articular cartilage calcification as hypointense foci using GRE techniques. Differential diagnosis includes loose bodies, post-surgical changes, marginal osteophytes and hemosiderin deposition.

Entrapment Neuropathies III: Lower Limb

Clinicians frequently encounter compressive neuropathies of the lower extremity. The clinical history and physical examination, along with electrodiagnostic testing and imaging studies, lead to the correct diagnosis. The imaging characteristics of the compression neuropathies can include acute and chronic changes in the nerves and the muscles they innervate. We provide a detailed review of compression neuropathies of the lower extremity with an emphasis on magnetic resonance (MR) imaging characteristics. We discuss the clinical presentation, etiology, anatomical location, and MR imaging appearance of these neuropathies, including the piriformis syndrome, iliacus syndrome, saphenous neuropathy, obturator neuropathy, lateral femoral cutaneous neuropathy (meralgia paresthetica), proximal tibial neuropathy, common peroneal neuropathy, deep peroneal neuropathy, superficial peroneal neuropathy, tarsal tunnel syndrome, Baxters neuropathy, joggers foot, sural neuropathy, and Mortons neuroma.

Diagnostic Accuracy of MRI in the Measurement of Glenoid Bone Loss

OBJECTIVE The purpose of this study is to assess the accuracy of MRI quantification of glenoid bone loss and to compare the diagnostic accuracy of MRI to CT in the measurement of glenoid bone loss. MATERIALS AND METHODS MRI, CT, and 3D CT examinations of 18 cadaveric glenoids were obtained after the creation of defects along the anterior and anteroinferior glenoid. The defects were measured by three readers separately and blindly using the circle method. These measurements were compared with measurements made on digital photographic images of the cadaveric glenoids. Paired sample Student t tests were used to compare the imaging modalities. Concordance correlation coefficients were also calculated to measure interobserver agreement. RESULTS Our data show that MRI could be used to accurately measure glenoid bone loss with a small margin of error (mean, 3.44%; range, 2.06-5.94%) in estimated percentage loss. MRI accuracy was similar to that of both CT and 3D CT for glenoid loss measurements in our study for the readers familiar with the circle method, with 1.3% as the maximum expected difference in accuracy of the percentage bone loss between the different modalities (95% confidence). CONCLUSION Glenoid bone loss can be accurately measured on MRI using the circle method. The MRI quantification of glenoid bone loss compares favorably to measurements obtained using 3D CT and CT. The accuracy of the measurements correlates with the level of training, and a learning curve is expected before mastering this technique.

MR Imaging of Complications of Anterior Cruciate Ligament Graft Reconstruction

During the past 3 decades, graft reconstruction of the anterior cruciate ligament (ACL) has become an accepted treatment for symptomatic ACL deficiency. The goal of surgery is to prevent joint instability, which may further damage articular cartilage and menisci. Graft failure is defined as pathologic laxity of the reconstructed ACL. The prevalence of recurrent instability after primary ACL reconstruction ranges from 1% to 8%. Early failures, those that occur within the first 6 months, often are secondary to poor surgical technique, failure of graft incorporation, or errors in rehabilitation. Late failures, those that occur more than 1 year after surgery, likely are related to new trauma and graft tearing. Other complications of ACL reconstruction include roof impingement, postoperative stiffness, tunnel widening due to cyst formation, iliotibial band friction syndrome, hardware failure, and infection. Magnetic resonance imaging is the preferred advanced imaging modality for the evaluation of symptomatic ACL graft reconstructions.

The middle glenohumeral ligament: normal anatomy, variants and pathology

The middle glenohumeral ligament frequently presents variations of the normal anatomy and it is often injured in patients suffering trauma to the glenohumeral joint. The purpose of this pictorial assay is to illustrate the normal anatomy, biomechanics, normal variants and pathology of the middle glenohumeral ligament, as shown on MRI and MR arthrography of the shoulder.

Bisphosphonate-Related Complete Atypical Subtrochanteric Femoral Fractures: Diagnostic Utility of Radiography

OBJECTIVE The objective of our study was to evaluate the diagnostic utility of conventional radiography for diagnosing bisphosphonate-related atypical subtrochanteric femoral fractures. MATERIALS AND METHODS Retrospective interpretation of 38 radiographs of complete subtrochanteric and diaphyseal femoral fractures in two patient groups-one group being treated with bisphosphonates (19 fractures in 17 patients) and a second group not being treated with bisphosphonates (19 fractures in 19 patients)-was performed by three radiologists. The readers assessed four imaging criteria: focal lateral cortical thickening, transverse fracture, medial femoral spike, and fracture comminution. The odds ratios and the sensitivity, specificity, and accuracy of each imaging criterion as a predictor of bisphosphonate-related fractures were calculated. Similarly, the interobserver agreement and the sensitivity, specificity, and accuracy of diagnosing bisphosphonate-related fractures (i.e., atypical femoral fractures) were determined for the three readers. RESULTS Among the candidate predictors of bisphosphonate-related fractures, focal lateral cortical thickening and transverse fracture had the highest odds ratios (76.4 and 10.1, respectively). Medial spike and comminution had odd ratios of 3.8 and 0.63, respectively. Focal lateral cortical thickening and transverse fracture were also the most accurate factors for detecting bisphosphonate-related fractures for all readers. The sensitivity, specificity, and overall accuracy for diagnosing bisphosphonate-related fractures were 94.7%, 100%, and 97.4% for reader 1; 94.7%, 68.4%, and 81.6% for reader 2; and 89.5%, 89.5%, and 89.5% for reader 3, respectively. The interobserver agreement was substantial (κ > 0.61). CONCLUSION Radiographs are reliable for distinguishing between complete femoral fractures related to bisphosphonate use and those not related to bisphosphonate use. Focal lateral cortical thickening and transverse fracture are the most dependable signs, showing high odds ratios and the highest accuracy for diagnosing these fractures.

Imaging of hip disorders in athletes.

Normal hip joint function is fundamental in running-, jumping-, and kicking-based sporting activities. Hip disorders do not account for a large portion of exercise-related injuries, but they can pose a clinical dilemma since symptoms tend to be non-specific. Conventional radiographs may demonstrate some causes of hip pain, such as stress fractures and degenerative joint disease. Magnetic resonance (MR) imaging of the hip has proven valuable in the diagnosis of radiographically occult osseous abnormalities and periarticular soft tissue disorders such as stress fractures, avulsion injuries, musculotendinous abnormalities, and bursitis. Conventional MR imaging has been less useful in the evaluation of intra-articular lesions including acetabular labral tears, intra-articular loose bodies, and cartilage lesions. The visualization of intra-articular structures and their abnormalities can be improved by the injection of diluted Gadolinium, which distends the capsule and leaks into labral tears. This article will focus on the use of conventional radiography and MR imaging in recreational and professional athletes with painful hip joints, and where possible it will compare MR imaging with other diagnostic modalities such as bone scan and CT.

Magnetic resonance imaging of the hip: sports-related injuries.

Normal hip disorders do not account for a large proportion of exercise-related injuries, but they can pose a clinical dilemma because symptoms tend to be nonspecific. Conventional radiographs may demonstrate some causes of hip pain, such as stress fractures and degenerative joint disease. Magnetic resonance imaging (MRI) of the hip has proven valuable in the diagnosis of radiographically occult osseous abnormalities and periarticular soft-tissue disorders such as stress fractures, avulsion injuries, musculotendinous abnormalities, and bursitis. Conventional MRI has been less useful in the evaluation of intra-articular lesions, including acetabular labral tears, intra-articular loose bodies, and cartilage lesions. Visualization of intra-articular structures and their abnormalities can be improved by injection of diluted gadolinium, which distends the capsule and leaks into labral tears. This article focuses on the use of conventional radiography and MRI in recreational and professional athletes with painful hip joints. Where possible, MRI is compared with other diagnostic modalities such as bone scan and computed tomography.