Ultrasound of the distal biceps brachii tendon using four approaches: reproducibility and reader preference.

OBJECTIVES: To determine which sonographic appearance of the distal biceps brachii tendon (DBBT) is preferred by readers, and if images obtained by two different operators are reproducible. METHODS: We performed an IRB-approved prospective sonographic evaluation of the DBBT in 50 healthy elbows using four different approaches (anterior, lateral, medial, posterior) performed by two operators. Five musculoskeletal radiologists independently reviewed the images, and ranked the four approaches based on overall appearance of echogenicity of the tendon, visualized length, and visualization of the insertion. RESULTS: The medial approach was preferred in 79.6% of elbows, anterior in 17.6%, lateral in 2.8%, and the posterior approach was never preferred. The difference was statistically significant (P < 0.001). Kappa values for the five readers were 0.61 to 0.8 for choosing the images produced by the medial approach. CONCLUSION: The appearance of the DBBT using the medial approach is preferred by readers and is reproducible between different operators.

Normal Skeletal Maturation and Imaging Pitfalls in the Pediatric Shoulder.

A growing number of magnetic resonance (MR) imaging studies of the shoulder are being performed as a result of greater and earlier participation of children and adolescents in competitive sports such as softball and baseball. However, scant information is available regarding the MR imaging features of the normal sequential development of the shoulder. The authors discuss the radiographic and MR imaging appearances of the normal musculoskeletal maturation patterns of the shoulder, with emphasis on (a) development of secondary ossification centers of the glenoid (including the subcoracoid and peripheral glenoid ossification centers); (b) development of preossification and secondary ossification centers of the humeral head and the variable appearance and number of the secondary ossification centers of the distal acromion, with emphasis on the formation of the os acromiale; (c) development of the growth plates, glenoid bone plates, glenoid bare area, and proximal humeral metaphyseal stripe; and (d) marrow signal alterations in the distal humerus, acromion, and clavicle. In addition, the authors discuss various imaging interpretation pitfalls inherent to the normal skeletal maturation of the shoulder, examining clues that may help distinguish normal development from true disease (eg, osteochondral lesions, labral tears, abscesses, fractures, infection, tendon disease, acromioclavicular widening, and os acromiale). Familiarity with the timing, location, and appearance of maturation patterns in the pediatric shoulder is crucial for correct image interpretation.

Skeletal development of the glenoid and glenoid-coracoid interface in the pediatric population: MRI features.

OBJECTIVE: To assess the MRI appearance of normal skeletal development of the glenoid and glenoid-coracoid interface in the pediatric population. To the best of our knowledge, this has not yet been studied in detail in the literature. MATERIALS AND METHODS: An IRB-approved, HIPAA-compliant retrospective review of 105 consecutive shoulder MRI studies in children, ages 2 months to 18 years was performed. The morphology, MR signal, and development of the following were assessed: (1) scapular-coracoid bipolar growth plate, (2) glenoid and glenoid-coracoid interface secondary ossification centers, (3) glenoid advancing osseous surface. RESULTS: The glenoid and glenoid-coracoid interface were identified in infancy as a contiguous, cartilaginous mass. A subcoracoid secondary ossification center in the superior glenoid was identified and fused in all by age 12 and 16, respectively. In ten studies, additional secondary ossification centers were identified in the inferior two-thirds of the glenoid. The initial concavity of the glenoid osseous surface gradually transformed to convexity, matching the convex glenoid articular surface. The glenoid growth plate fused by 16 years of age. Our study, based on MRI, demonstrated a similar pattern of development of the glenoid and glenoid coracoid interface to previously reported anatomic and radiographic studies, except for an earlier development and fusion of the secondary ossification centers of the inferior glenoid. CONCLUSIONS: The pattern of skeletal development of the glenoid and glenoid-coracoid interface follows a chronological order, which can serve as a guideline when interpreting MRI studies in children.

Skeletal development of the proximal humerus in the pediatric population: MRI features.

OBJECTIVE: The purpose of this study was to provide a guideline of normal MRI developmental anatomy of the proximal humerus in a growing child. MATERIALS AND METHODS: Retrospective interpretation of 83 consecutive MRI studies of shoulders in children 2 months to 17 years old was performed in consensus by two radiologists. The following variables were documented: presence, number, and fusion of secondary ossification centers; appearance and closure of the growth plate; presence of the metaphyseal stripe; and proximal metaphyseal marrow signal intensity. RESULTS: Preossification centers were seen in 2- and 4-month-old patients. Secondary ossification centers appeared in the medial humeral head and greater tuberosity at 4 and 10 months, respectively, originally depicting red marrow and later converting to yellow marrow. A separate lesser tuberosity ossification center was not seen. The ossification centers began fusing by 3 years and gradually conformed to the final shape of the proximal humerus. Ossification was completed by 13 years. The multilaminar growth plate initially had a flat and smooth contour that progressively became irregular and pyramidal, closing at 17 years. The metaphyseal stripe was noted at infancy and disappeared by 15.5 years. The metaphyseal marrow signal intensity was diffusely low in infants but, with conversion to yellow marrow, showed proximal metaphyseal bright patchy or linear signal-intensity, eventually disappearing by 17 years. CONCLUSION: The postnatal skeletal development of the proximal humerus in the pediatric population follows distinctive sequential patterns of maturation, which can serve as a guideline for interpreting MRI studies in children.