Andrew Kompel

Imaging characteristics of contralateral asymptomatic patellofemoral joints in patients with unilateral instability.

PURPOSE To test the hypothesis that in patients with unilateral patellofemoral instability ( PI patellofemoral instability ), the contralateral asymptomatic joints have abnormal morphology and imaging features of osteoarthritis ( OA osteoarthritis ) at four-dimensional ( 4D four-dimensional ) computed tomography (CT). MATERIALS AND METHODS The institutional review board approved this HIPAA-compliant retrospective study. Informed consent was waived. Radiology records were reviewed to identify 25 patients (male-female ratio, 0.56; median age, 20 years; range, 13-43 years) with unilateral PI patellofemoral instability undergoing 4D four-dimensional CT and 25 age- and sex-matched control patients undergoing multidetector CT. Trochlear groove depth ( TGD trochlear groove depth ), tibial tuberosity-trochlear groove ( TT-TG tibial tuberosity-trochlear groove ) distance, and patellar height ratio ( PHR patellar height ratio ) were determined to compare morphology, and bisect offset ( BO bisect offset ) measurements were obtained to compare lateral displacement of the patella between the two groups by using the Wilcoxon rank-sum test. All images were interpreted by trained observers. Tracking patterns of the patellae were determined by obtaining BO bisect offset measurements at various flexion angles with 4D four-dimensional CT. RESULTS In the contralateral asymptomatic joints, TGD trochlear groove depth (median, 3.0 mm; 95% confidence interval [ CI confidence interval ]: 2.5, 4.6; P < .0001), TT-TG tibial tuberosity-trochlear groove (median, 15 mm; 95% CI confidence interval : 12.7, 18; P = .008), PHR patellar height ratio (median, 1.17; 95% CI confidence interval : 1.09, 1.2; P = .002), and patellar lateral displacement ( BO bisect offset , 85%; 95% CI confidence interval : 76.2%, 98.2%; P < .0001) were different from measurements obtained in the control group: TGD trochlear groove depth median, 5.0 mm (95% CI confidence interval : 2.2, 7.6); TT-TG tibial tuberosity-trochlear groove median, 10.9 mm (95% CI confidence interval : 3.4, 20.7); PHR patellar height ratio median, 0.92 (95% CI confidence interval : 0.67, 1.36); and BO bisect offset median, 63% (95% CI confidence interval : 59%, 68.4%). OA osteoarthritis was detected in 40% of asymmetrical contralateral joints (10 of 25). By using 4D four-dimensional CT data, multiple regression analysis demonstrated that TGD trochlear groove depth (P = .026) and BO bisect offset measurements obtained at 30° of knee flexion (P = .047) had an association with the presence of OA osteoarthritis . CONCLUSION Abnormal morphology and imaging features of OA osteoarthritis are relatively common in contralateral asymptomatic joints of young patients with unilateral PI patellofemoral instability .

Association of mucoid degeneration of anterior cruciate ligament with knee meniscal and cartilage damage

OBJECTIVE To assess the prevalence of anterior cruciate ligament (ACL) mucoid degeneration in patients referred for routine knee magnetic resonance (MR) imaging, and its association with age and structural joint damage. METHOD Four independent radiologists assessed 413 consecutive knee MR examinations for the presence of a normal or ruptured ACL, or ACL mucoid degeneration. Knees with ACL mucoid degeneration were frequency matched by age, sex, and MR field strength with consecutive control knees with a normal ACL (1:2 ratio). Differences in meniscal and cartilage damage of the tibiofemoral compartments, as determined by the Whole-Organ MR Imaging Score (WORMS) system, were compared by Mann-Whitney U tests. Multivariable logistic regression analysis identified the association of ACL mucoid degeneration with severe MTFC cartilage damage (WORMS≥5). RESULTS Patients with ACL mucoid degeneration (n = 36; 36% males; median age 55.5 years, range: 26-81) were older than patients with a normal (P < 0.001) or ruptured ACL (P < 0.001), without sex predilection (P = 0.76), and were more frequently diagnosed at 3 T (12%) compared to 1.5 T (2%). Knees with ACL mucoid degeneration had statistically significantly more medial meniscal (P < 0.001) and central and posterior medial tibiofemoral compartment (MTFC) cartilage (P < 0.001) damage compared with control knees (n = 72), but there were no differences in patients ≤50 years (P = 0.09 and 0.32, respectively). In multivariable logistic regression, severe MTFC cartilage damage (WORMS≥5) was significantly associated with ACL mucoid degeneration (odds ratio 4.09, 95% confidence interval 1.29-12.94, P = 0.016). CONCLUSION There is a strong association between ACL mucoid degeneration and cartilage damage in the central and posterior MTFC, especially in patients >50 years.

Rotator Cuff Tear Arthropathy: Pathophysiology, Imaging Characteristics, and Treatment Options.

OBJECTIVE The purpose of this article is to review the biomechanical properties of the rotator cuff and glenohumeral joint and the pathophysiology, imaging characteristics, and treatment options of rotator cuff tear arthropathy (RCTA). CONCLUSION Although multiple pathways have been proposed as causes of RCTA, the exact cause remains unclear. Increasing knowledge about the clinical diagnosis, imaging features, and indicators of severity improves recognition and treatment of this pathologic condition.

Magnetic Resonance Imaging of Nontraumatic Musculoskeletal Emergencies

Many pathologies of the musculoskeletal system involve nontraumatic causes. MR imaging is used in the diagnosis because of its high sensitivity and specificity compared with other modalities. Osteomyelitis, osteonecrosis of the femoral head, and stress fractures are pathologies of bone where early diagnosis and intervention usually lead to an improved outcome. Joint aspiration and culture is the standard for diagnosing septic arthritis. MR imaging can support the diagnosis and allows evaluation for adjacent abscess and osteomyelitis. Early in the disease process, necrotizing fasciitis may not be clinically suspected and imaging may provide the first indication of the presence of this potentially deadly infection.

Radiographic Evaluation of Patients with Anterior Shoulder Instability

Purpose of ReviewInjuries to the labrum, joint capsule (in particular the inferior glenohumeral ligament), cartilage, and glenoid periosteum are associated with anterior shoulder instability. The goal of this review is to provide common radiographic images and findings in patients with anterior shoulder instability. Furthermore, we will demonstrate the best methods for measuring anterior glenoid bone loss.Recent FindingsMagnetic resonance (MR) imaging is highly relied upon for evaluating anterior shoulder instability and can diagnose soft tissue injuries with high sensitivity. While 3D computed tomography (CT) scan has been considered the optimal tool for evaluating osseous defects, certain MR imaging sequences have been shown to have similar diagnostic accuracy. Repair of Bankart lesions is critical to stabilizing the shoulder, and in the recent years, there has been an increasing focus on imaging to accurately characterize and measure glenoid bone loss to properly indicate patients for either arthroscopic repair or anterior bony reconstruction. Furthermore, Hill-Sachs lesions are commonly seen with shoulder instability, and importance must be placed on measuring the size and depth of these lesions along with possible engagement, as these factors will dictate management.SummaryThe labral-ligamentous complex and rotator cuff are primary stabilizers of the shoulder. With anterior shoulder instability, the labrum is frequently injured. MRI with an arthrogram or provocative maneuvers is the gold standard for diagnosis. Various imaging modalities and methods can be performed to identify and measure Bankart and Hill-Sachs lesions, which can then be used for surgical planning and treating shoulder instability.

MRI-Detected Sports-Related Knee Injuries and Abnormalities at the Rio de Janeiro 2016 Summer Olympic Games

OBJECTIVE The purpose of this article is to describe knee abnormalities and the occurrence of MRI-detected sports-related knee abnormalities by evaluating MRI examinations performed during the Rio de Janeiro Olympic Games held in August 2016. CONCLUSION There were 11,274 athletes at the Rio 2016 Olympic Games, and 113 of them underwent at least one knee MRI in the Olympic Village. Cartilage abnormalities, followed by meniscal tears and ligament sprains, were the most frequent abnormalities.

Development of an imaging mitigation strategy for patient enrolment in the tanezumab nerve growth factor inhibitor (NGF-ab) program with a focus on eligibility assessment

OBJECTIVE Nerve growth factor antibodies (NGF-ab) have shown promising analgesic efficacy. Aim was to describe reader training efforts and present reliability data focusing on radiographic eligibility in the tanezumab program. METHODS A multi-step process was used for reader calibration and reliability testing. First, a reference standard set of cases was created and diagnostic performance was evaluated. A second exercise focused on agreement of ordinal assessment (Kellgren-Lawrence grading) of radiographic osteoarthritis. Subsequently, 11 readers were trained and read a test set of 100 cases focused on eligibility assessments. Additional reliability testing and calibration of five core readers assessing eligibility of 30 cases was performed 3 and 6 months after study start. RESULTS Sensitivity for the reference standard readings ranged from 0.50 to 0.90 and specificity from 0.40 to 0.83. Overall agreement for Kellgren-Lawrence grading ranged from 71.4% to 82.9%. For the 11 reader exercise, in 76% of cases at least 8 of 11 readers agreed on eligibility status. For the reliability testing 3 months after study start, in 80.0% of cases at least 4 of 5 readers agreed on eligibility with a κ = 0.43 (95% CI: 0.32-0.54). For the reliability testing after 6 months, in 83.3% of cases at least 4 of 5 readers agreed on eligibility with a κ = 0.52 (95% CI: 0.41-0.63). CONCLUSIONS After intense efforts spent in the development of an imaging program for an NGF-ab clinical program, the achieved reliability for eligibility assessment is substantial but not perfect. Ongoing efforts of calibration prior to including additional readers to the program and during study conduct between current readers will be needed to ensure agreement on potential adverse events and radiographic disease severity.

Imaging of the Carpal Tunnel and Median Nerve

Carpal tunnel syndrome (CTS) is primarily a clinical diagnosis; however, recent advances in diagnostic imaging have increased the relevance of magnetic resonance imaging (MRI) and ultrasound (US) in the clinical evaluation. There are a variety of imaging findings of CTS that are well depicted on both modalities that have varied sensitivities and specificities. In MRI, the most commonly used criteria for CTS are increased median nerve size, median nerve flattening, median nerve signal change, and flexor retinaculum bowing. In ultrasound, measuring the cross-sectional area of the nerve at the level of the pisiform or carpal tunnel inlet detects CTS with a sensitivity and specificity that is similar to electrodiagnostic tests (EDTs). Both CT and ultrasound can aid in identifying alternative causes of nerve compression, such as ganglion cysts, masses, or flexor tenosynovitis. Future research in CTS imaging will include the use of MRI diffusion tensor imaging and ultrasound elastography.

Imaging of American Football Injuries

American football games are a centerpiece of sports culture in the United States. The excitement and physicality make the sport attractive to fans, and yet the athletes put themselves at risk for injury with every snap of the football. While this is true for many sports, gridiron football has the highest rate of injury among all major sports. Catastrophic injuries have declined with improvements in equipment, coaching, and rule modification. At the same time, however, advancements in training methods over the past few decades have led to bigger, stronger, and faster players. The result is harder tackles and quicker cutting and pivoting movements that make the game more exciting to watch but lead to frequent musculoskeletal injuries. Lower extremity injuries are the most common, with the knee and ankle the most frequently injured. Sprains and strains occur more often than bone injuries or concussions. Given that more injuries involve the soft tissues, MRI has a distinct advantage over radiography and CT for direct evaluation of the injury. The high accuracy of MRI in diagnosis has lead to its increased utilization especially among professional athletes. In addition, concomitant injuries may be discovered that were unsuspected on physical exam and radiography. Ultimately, the player is the main determinant when deciding when to return to play from an injury, although imaging can assist in the treatment algorithm and help estimate the number of potential missed games.