The Veil of Obscuration: Additional Radiographic Sign of Posterior Shoulder Dislocation.

OBJECTIVE: To describe a new radiographic sign, "veil of obscuration", associated with posterior glenohumeral joint (shoulder) dislocations and determine its incidence and validity compared to other known classic radiographic signs. METHODS: Four-year retrospective study identified 30 acute posterior shoulder dislocation patients. Radiographs reviewed in consensus by 2 musculoskeletal radiologists for the "veil of obscuration", seen on AP shoulder radiographs and representing a comminuted fracture of the lesser tuberosity projecting over the humeral head or glenohumeral joint. Incidence of this radiographic sign of posterior glenohumeral joint dislocation in addition to other previously described classic radiographic signs, and association with other fractures, surgery, and mechanism of injury were evaluated. Continuous data was analyzed with student t-test and categorical data with Chi-Square test. RESULTS: There were 20 right and 10 left posterior shoulder dislocations. Majority of injuries resulted from vehicle crash (44%). In most cases, reverse Hill-Sachs lesion (83%) and fixed internal rotation of the humeral head (76%) were present, followed by trough line (43%) and "veil of obscuration" (40%). Trough line was seen in significantly more major trauma and vehicle crashes (78% and 46%; P=0.015), while "veil of obscuration" was seen in more seizures (86%; P=0.037) and in all surgical patients. No significant difference in presence of other classic radiographic signs in regards to surgery. CONCLUSION: The newly described radiographic sign of posterior shoulder dislocations named the "veil of obscuration" has comparable incidence as other classic radiographic signs and may be useful in the recognition and diagnosis of these injuries.

Humeral avulsion of the inferior glenohumeral ligament in college female volleyball players caused by repetitive microtrauma.

BACKGROUND: Humeral avulsion of the inferior glenohumeral ligament is a rare injury resulting from hyperabduction and external rotation, and it is most commonly seen with sports-related injuries, including those from volleyball. The anterior band of the inferior glenohumeral ligament is most commonly injured (93%), whereas the posterior band is infrequently injured. The axillary pouch humeral avulsion of the inferior glenohumeral ligament as a result of repetitive microtrauma has not been yet described in the English literature. HYPOTHESIS: Humeral avulsions of the inferior glenohumeral ligaments are identifiable in volleyball players without acute injuries, and they have a unique pathologic pattern in these athletes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Four female college volleyball players with pain in their dominant shoulder and with inferior capsular laxity and/or instability­without a known history of trauma or dislocation of the same shoulder­were referred by an experienced sports medicine orthopaedic surgeon for the magnetic resonance arthrogram procedure of the same shoulder. The imaging findings were retrospectively correlated with the initial interpretation and arthroscopic findings. RESULTS: All 4 patients had an axillary pouch humeral avulsion of the inferior glenohumeral ligament. Three had articular surface partial-thickness rotator cuff tear, and 3 had a labral tear. All were outside hitters or middle blockers who consequently performed multiple hitting maneuvers in practice and games. CONCLUSION: Repetitive microtrauma from overhead hitting in volleyball generates forces on the inferior capsule of the shoulder joint that may cause inferior capsular laxity and subsequent failure of the humeral side of the axillary pouch portion of the inferior glenohumeral ligament.

US of the intrinsic and extrinsic wrist ligaments and triangular fibrocartilage complex--normal anatomy and imaging technique.

Injuries of the intrinsic and extrinsic wrist ligaments can lead to chronic wrist pain and carpal instability, while injuries of the triangular fibrocartilage complex are a frequent cause of ulnar-sided wrist pain. Currently, magnetic resonance (MR) arthrography is the preferred imaging modality for the evaluation of these structures, but good results can also achieved with MR imaging without preceding arthrography and computed tomographic (CT) arthrography. Promising results have been published on ultrasonography (US) and sonoarthrography of the intrinsic wrist ligaments and the triangular fibrocartilage complex and on US of the majority of extrinsic wrist ligaments. Visualization of these structures can be achieved by using high-frequency linear transducers. US has the advantages of MR imaging and MR arthrography: lower cost, no known contraindication for imaging, and real-time technique with possible dynamic evaluation. This technique does not require imaging guided intraarticular injection of contrast medium prior to MR arthrography or CT arthrography and does not use ionizing radiation; however, US is operator dependent, which can be compensated for by using standardized imaging techniques. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.e44/-/DC1.

Diagnosis of proximal femoral insufficiency fractures in patients receiving bisphosphonate therapy.

OBJECTIVE: The purpose of this article is to describe the imaging features of proximal femoral insufficiency fractures in patients on long-term bisphosphonate therapy. CONCLUSION: The imaging findings of bisphosphonate-related femoral insufficiency fractures, which include a typical proximal diaphyseal location and transverse liner radiolucency through localized thickening of the lateral cortex, allow a specific diagnosis.

The importance of sagittal 2D reconstruction in pelvic and sacral trauma: avoiding oversight of U-shaped fractures of the sacrum.

OBJECTIVE: The U-shaped sacral fracture can be overlooked without appropriate imaging. Radiographic and CT imaging of seven patients with U-shaped sacral fractures was reviewed. CONCLUSION: Although it is difficult to discern on anteroposterior radiographs and axial or coronal CT, the fracture is easily identifiable on CT images in the sagittal plane. We advocate reconstruction of CT images of the sacrum in the sagittal plane in trauma to prevent failure of identification.

Imaging of musculoskeletal soft tissue infections.

Prompt and appropriate imaging work-up of the various musculoskeletal soft tissue infections aids early diagnosis and treatment and decreases the risk of complications resulting from misdiagnosis or delayed diagnosis. The signs and symptoms of musculoskeletal soft tissue infections can be nonspecific, making it clinically difficult to distinguish between disease processes and the extent of disease. Magnetic resonance imaging (MRI) is the imaging modality of choice in the evaluation of soft tissue infections. Computed tomography (CT), ultrasound, radiography and nuclear medicine studies are considered ancillary. This manuscript illustrates representative images of superficial and deep soft tissue infections such as infectious cellulitis, superficial and deep fasciitis, including the necrotizing fasciitis, pyomyositis/soft tissue abscess, septic bursitis and tenosynovitis on different imaging modalities, with emphasis on MRI. Typical histopathologic findings of soft tissue infections are also presented. The imaging approach described in the manuscript is based on relevant literature and authors' personal experience and everyday practice.

Imaging characteristics of diffuse idiopathic skeletal hyperostosis with an emphasis on acute spinal fractures: review.

OBJECTIVE: The educational objectives of this self-assessment module are for the participant to exercise, self-assess, and improve his or her understanding of the imaging of diffuse idiopathic skeletal hyperostosis (DISH), with emphasis on acute spinal fractures. CONCLUSION: Understanding the pathomechanics of the fractures in the ankylosed spine is important in the differentiation of the acute spinal fractures in DISH and ankylosing spondylitis. This article emphasizes the imaging features of spinal DISH and acute spinal fractures in DISH, distinguishing them specifically from those in ankylosing spondylitis.

Imaging characteristics of diffuse idiopathic skeletal hyperostosis with an emphasis on acute spinal fractures: self-assessment module.

The educational objectives for this self-assessment module are for the participant to exercise, self-assess, and improve his or her understanding of the imaging of diffuse idiopathic skeletal hyperostosis (DISH).

Interaction between academic radiology and the news media: a potentially powerful and unpredictable process--five stories.

OBJECTIVE: Although articles have been published describing the relationship between news reports and the general medical literature, to our knowledge little has been published describing the relationship between radiology publications and news coverage. We present five instances of news stories centered on radiology publications or abstracts of presentations at national meetings and the effect of the media coverage within the medical community. CONCLUSION: The five examples show that news coverage can have a dramatic effect on advancing research findings and public health information published in radiology journals. Even when news coverage is inaccurate or sensationalized, the attention of the general public can drive change not only generally in medicine but also specifically in radiology.

Update on imaging and treatment of Ewing sarcoma family tumors: what the radiologist needs to know.

This review article provides an update on multimodality imaging characteristics of Ewing sarcoma family tumors. Pathology of this tumor and current trends in medical and surgical treatment are briefly discussed.

Sonography and sonoarthrography of the scapholunate and lunotriquetral ligaments and triangular fibrocartilage disk: initial experience and correlation with arthrography and magnetic resonance arthrography.

OBJECTIVE: The purpose of this study was to determine the utility of sonography and sonoarthrography in evaluation of dorsal bands of the scapholunate ligament (SLL), lunotriquetral ligament (LTL), and triangular fibrocartilage (TFC) disk in correlation with arthrography and magnetic resonance arthrography (MRA). METHODS: High-resolution sonography of the SLL, LTL, and TFC disk was performed on symptomatic wrists in 16 patients referred by a hand surgeon for MRA of the symptomatic wrists. All patients then underwent arthrography and an MRA study of the same wrist. After MRA, sonography was repeated. The imaging findings of these different techniques were then compared. Four patients (25%) underwent surgery of their wrists. In these 4 patients, the surgical and imaging findings were correlated. RESULTS: For the SLL, the results were concordant for all imaging modalities in 15 patients (93.75%) and partially concordant in 1 (6.25%). For the LTL, the results were concordant for all imaging modalities in 12 patients (75%), partially concordant in 3 (18.75%), and discordant in 1 (6.25%). For the TFC disk, the results were concordant for all imaging modalities in 13 patients (81.25%), partially concordant in 2 (12.5%), and discordant in 1 (6.25%). The arthroscopic and imaging findings were concordant for 3 SLLs, 3 LTLs, and 3 TFC disks. CONCLUSIONS: Our preliminary results are encouraging. Sonography may be used at least as a screening imaging modality in evaluation of the SLL and TFC disk. Sonoarthrography improves evaluation of the LTL.

CT findings of rupture, impending rupture, and contained rupture of abdominal aortic aneurysms.

OBJECTIVE: With the increasing use of cross-sectional imaging for a variety of medical and surgical conditions affecting the abdomen and pelvis, familiarity with the imaging features of aneurysm rupture--and the findings suspicious for impending or contained aneurysm rupture--is crucial for all radiologists. This pictorial essay will review the imaging findings of rupture of abdominal aortic aneurysms and of complicated aneurysms. CONCLUSION: Prompt detection of abdominal aortic aneurysm rupture or impending rupture is critical because emergent surgery may be required and patient survival may be at stake.