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Biomedical subjects

Javier Beltran

Publications and source records attributed to Javier Beltran.

13 recordsLinked to original sources

MR imaging of the glenohumeral ligaments.

The glenohumeral ligaments, particularly the inferior one, are the major passive stabilizers of the joint, and the labrum functions as a site of ligamentous attachment. The strong union between the collagen fibers of the glenohumeral ligaments and the glenoid labrum is more resistant to injury than the union between the glenoid rim and the labrum. Labral tears associated with glenohumeral instability are therefore usually secondary to avulsion rather than impaction. This article reviews the normal MR imaging anatomy, variants and pitfalls of the glenohumeral ligaments, and the basic biomechanics of the glenohumeral ligaments. Examples of injuries involving these structures are provided.

Biomechanical Phenomena↗

MR imaging: Arthropathies and infectious conditions of the elbow, wrist, and hand.

The superior soft tissue contrast and multiplanar capability of MR imaging has contributed to earlier diagnosis and implementation of effective treatment for a variety of arthropathies and infectious conditions of the elbow, wrist, and hand. Because of overlapping clinical signs and symptoms, MR imaging plays an important role in delineating the features and staging of each of these conditions. This article discusses the seropositive and seronegative inflammatory arthropathies, with emphasis on early detection and surveillance, as well as gout, synovial osteochondromatosis, pigmented villonodular synovitis, tenosynovitis, and de Quervain's tenosynovitis. Certain noninflammatory arthritides and infectious conditions are also reviewed.

Elbow Joint↗

MR imaging of the hip: osseous lesions.

Because of the exquisite soft tissue contrast resolution of MR imaging combined with recent technologic developments, a variety of conditions involving the hip joint and adjacent bony structures can be well evaluated using MR imaging, with or without contrast material. Among the different conditions, hip trauma and avascular necrosis are the most frequent indications. Other entities for which MR imaging has proven its usefulness include subchondral fractures, osteochondritis dissecans, transient osteoporosis, bone tumors, inflammatory and infectious processes, and a variety of bone marrow disorders.

Adult↗

Shoulder MR arthrography: how, why, when.

This article reviews current MR techniques for shoulder imaging, discusses advantages and disadvantages of each, and reviews the literature regarding sensitivity, specificity, and accuracy of MR arthrography versus nonenhanced MR in the evaluation of shoulder pathology, specifically, glenoid labral tears and rotator cuff tears.

Contrast Media↗

MR imaging of tumors and tumor-like lesions of the upper extremity.

Many tumor and tumor-like lesions of the bone and soft tissues may involve the upper extremity. Certain lesions, however, are unique to this location. As is usually the case, MR is most sensitive to detection and most accurate in depicting the extent of involvement of these lesions. MR signal characteristics may aid in differential diagnosis. Conventional radiographs are often more specific in regard to the underlying histopathology.

Arm↗

MR imaging: arthropathies and infectious conditions of the elbow, wrist, and hand.

The superior soft tissue contrast and multiplanar capability of MR imaging has contributed to earlier diagnosis and implementation of effective treatment for a variety of arthropathies and infectious conditions of the elbow, wrist, and hand. Because of overlapping clinical signs and symptoms, MR imaging plays an important role in delineating the features and staging of each of these conditions. This article discusses the seropositive and seronegative inflammatory arthropathies, with emphasis on early detection and surveillance, as well as gout, synovial osteochondromatosis, pigmented villonodular synovitis, tenosynovitis, and de Quervain's tenosynovitis. Certain noninflammatory arthritides and infectious conditions are also reviewed.

Bacterial Infections↗

The distal semimembranosus complex: normal MR anatomy, variants, biomechanics and pathology.

OBJECTIVE: To describe the normal MR anatomy and variations of the distal semimembranosus tendinous arms and the posterior oblique ligament as seen in the three orthogonal planes, to review the biomechanics of this complex and to illustrate pathologic examples. RESULTS AND CONCLUSION: The distal semimembranosus tendon divides into five tendinous arms named the anterior, direct, capsular, inferior and the oblique popliteal ligament. These arms intertwine with the branches of the posterior oblique ligament in the posterior medial aspect of the knee, providing stability. This tendon-ligamentous complex also acts synergistically with the popliteus muscle and actively pulls the posterior horn of the medial meniscus during knee flexion. Pathologic conditions involving this complex include complete and partial tears, insertional tendinosis, avulsion fractures and bursitis.

Biomechanical Phenomena↗

MR imaging of shoulder instability injuries in the athlete.

Lesions leading to glenohumeral instability may result from acute trauma, atraumatic laxity, or repetitive microtrauma. Athletic activities, especially overhead throwing, may lead to a series of lesions involving the stabilizing structures of the shoulder. The resultant injuries and pathomechanics leading to shoulder symptoms can be classified as primary disease, primary instability, acute traumatic instability, and posterosuperior impingment syndrome. MR imaging with or without intrarticular or intravenous injection of contrast material, along with clinical examination and stress testing, provides valuable preoperative assessment.

Athletic Injuries↗

Shoulder: labrum and bicipital tendon.

Shoulder instability can be due to a single, acute traumatic event, generalized joint laxity, or repeated episodes of microtrauma. The later occurs in the throwing athlete. The most common lesion involving the labrum is the anterior inferior labral tear, associated with capsuloperiosteal stripping (classic Bankart lesion). A number of variants of the Bankart lesion have been described recently and include the ALPSA lesion, SLAP lesion, and HAGHL lesion, among others. Lesions of the long head of the biceps tendon can be seen in isolation (tears, tendinosis, dislocation) or in association with rotator cuff and labral lesions. Conventional MR and MR arthrography have been extensively used for the preoperative diagnosis of these lesions, with reportedly good accuracy. An understanding of the normal anatomy and biomechanics of the shoulder joint is essential for proper interpretation of the MRI manifestations of these conditions.

Athletic Injuries↗

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.

Biomechanical Phenomena↗

MRI of Normal Variants and Interpretation Pitfalls of the Elbow.

One of the fundamental principles of MR imaging interpretation is the ability to distinguish normal anatomical landmarks from true disease. The radiologist is thus compelled to accumulate a comprehensive knowledge of normal structures, variants, and potential MRI diagnostic pitfalls.1-5 In this article we will focus on a number of normal bony, ligamentous, and tendinous structures that can simulate disease at the elbow. We discuss the particular anatomy responsible for the appearance of each of these interpretation pitfalls as well as the distinguishing features between these normal variants and true disease.

Journal Article↗

Nerve Entrapment.

Entrapment and compressive neuropathies are frequent clinical conditions occurring about the elbow. In most instances clinical and electromyograhic evaluation are adequate for patient management, but in some cases further evaluation with imaging techniques is required. Magnetic resonance imaging (MRI) has been shown to be useful in the evaluation of these conditions, especially to detect space occupying lesions. In this article, compressive neuropathies involving the ulnar, median, and radial nerves are discussed, with emphasis on the normal anatomy and the MRI depiction of pathologic findings.

Journal Article↗