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The thumb is a central component supporting the intricate movements of the hand. Patients with acute thumb pain, particularly after trauma, require prompt evaluation of structural integrity, thus avoiding long-term morbidity such as instability, chronic pain, and osteoarthritis. Injury to the ulnar collateral ligament (UCL) of the thumb requires imaging for diagnosis of surgically important entities such as the Stener lesion. Historically, routine radiography including stress views does not allow such diagnosis and is potentially detrimental to patient care. Both magnetic resonance imaging and ultrasonography (US) are currently used for direct evaluation of the UCL of the thumb and are safe and accurate. US is more dynamic and less time-consuming and may be easier to perform. Furthermore, other disorders such as tenosynovitis, tendon tears, and articular pathologic conditions can involve the thumb and thenar region and may also be diagnosed with US. In this context, US is an underused tool because it is potentially an adjunct to the clinical examination in the appropriate setting. A sound knowledge of the regional anatomy and basic training in the principles of US should equip the imager with the skills necessary to evaluate the UCL of the thumb and its surrounding structures., (Copyright RSNA, 2006)

Objective: The objective of this study was to retrospectively review sonographic images of pathologically proven soft tissue myxomas to determine whether a sonographic correlate to the bright rim and bright cap signs described in the magnetic resonance imaging literature is present., Methods: The study group consisted of 6 patients with pathologically proven soft tissue myxomas (1 man and 5 women; age range, 41-72 years; mean, 56.5 years). The available sonographic images for each subject were retrospectively reviewed by 2 authors (L.F. and K.F.), with agreement reached by consensus. Among other findings, images were also reviewed for a peripheral rim of increased echogenicity (termed the "bright rim sign") and for the presence of a triangular hyperechoic area adjacent to at least one of the poles of the mass (termed the "bright cap sign")., Results: The bright rim and bright cap signs were seen in 5 (83%) of the 6 myxomas. The single case without the bright cap sign was not the same case as the one lacking the bright rim sign., Conclusions: The sonographic bright rim and bright cap signs were associated with 5 (83%) of the 6 intramuscular myxomas. These findings correlate with their magnetic resonance imaging equivalents, which are well documented in the literature, due to muscle atrophy and adjacent fatty infiltration. Recognition of these features may assist in a more accurate sonographic diagnosis before biopsy.

The rotator cuff muscles generate torque forces to move the humerus while acting in concord to produce balanced compressive forces to stabilize the glenohumeral joint. Thus, rotator cuff tears are often associated with loss of shoulder strength and stability, which are crucial for optimal shoulder function. The dimensions and extent of rotator cuff tears, the condition of the involved tendon, tear morphologic features, involvement of the subscapularis and infraspinatus tendons or of contiguous structures (eg, rotator interval, long head of the biceps brachii tendon, specific cuff tendons), and evidence of muscle atrophy may all have implications for rotator cuff treatment and prognosis. Magnetic resonance imaging can demonstrate the extent and configuration of rotator cuff abnormalities, suggest mechanical imbalance within the cuff, and document abnormalities of the cuff muscles and adjacent structures. A thorough understanding of the anatomy and function of the rotator cuff and of the consequences of rotator cuff disorders is essential for optimal treatment planning and prognostic accuracy. Identifying the disorder, understanding the potential clinical consequences, and reporting all relevant findings at rotator cuff imaging are also essential., (Copyright RSNA, 2006)

Objective: The purpose of this article is to describe the anatomy of the inguinal region in a way that is useful for sonographic diagnosis of inguinal region hernias, and to illustrate the sonographic appearance of this anatomy. We show sonographic techniques for evaluating inguinal, femoral, and spigelian hernias and include surgically proven examples., Conclusion: Understanding healthy inguinal anatomy is essential for diagnosing inguinal region hernias. Sonography can diagnose and differentiate between various inguinal region hernias.

Musculoskeletal ultrasound is a low-cost, noninvasive method of evaluating orthopaedic trauma patients. It is particularly useful for patients with metallic hardware, which may degrade computed tomography or magnetic resonance images. Ultrasound has been used to evaluate fracture union and nonunion, infection, ligamentous injury, nerve compression, and mechanical impingement caused by hardware. Real-time dynamic examination allows identification of pathology and provides direct correlation between symptoms and the observed pathology.

Purpose: To retrospectively evaluate the imaging features of os peroneum fractures and associated peroneus longus tendon injuries at radiography and ultrasonography (US) and to retrospectively compare these imaging features with those of multipartite os peroneum., Materials and Methods: Institutional review board approval was obtained and informed consent was waived for this HIPAA-compliant study. Retrospective review of findings in nine patients (five men, four women; age range, 35-59 years) with os peroneum fracture at radiography and lateral foot pain after injury who had undergone US of the foot was performed. Three patients underwent magnetic resonance (MR) imaging, and two underwent surgery. Os peroneum fragment separation and displacement relative to the calcaneocuboid joint were measured on radiographs. Os peroneum fracture and peroneus longus tendon injuries were characterized with US and MR imaging. Review of 43 foot radiographs obtained in 36 control subjects (eight men, 28 women; age range, 18-84 years) who were found to have an os peroneum at radiography but were asymptomatic in that area was completed to measure os peroneum distance from the calcaneocuboid joint and bipartite os peroneum fragment distraction., Results: Os peroneum fragment separation of 6 mm or more or displacement of the proximal fragment by 10 mm or more on a lateral radiograph or 20 mm or more on an oblique radiograph was associated with full-thickness peroneus longus tendon tear in seven of seven patients (100%). Os peroneum fragment separation of 2 mm or less or proximal displacement of 8 mm or less was associated with normal tendons, partial-thickness tears, or tendinosis. In the control subjects, os peroneum location ranged from 7 mm proximal to 8 mm distal to the calcaneocuboid joint on lateral radiographs and from 9 mm proximal to 8 mm distal to the joint on oblique radiographs. Bipartite os peroneum fragment separation was 2 mm or less., Conclusion: Os peroneum fragment separation of 6 mm or more suggests os peroneum fracture and associated full-thickness peroneus longus tendon tear. Separation of 2 mm or less may be seen with nondisplaced os peroneum fractures and bipartite os peroneum., (RSNA, 2005)

Background: Stress radiography has been the established imaging method for quantifying glenohumeral joint laxity. Dynamic ultrasound is an alternative imaging method that may be used to measure glenohumeral laxity; however, validity and repeatability have not been examined., Objective: To determine criterion-related validity and repeatability of a sonographic imaging method for measuring glenohumeral laxity in asymptomatic shoulders., Study Design: Controlled laboratory study., Methods: In experiment 1, 20 subjects were assessed for glenohumeral laxity using stress radiography and dynamic ultrasound. In the second experiment, 13 subjects were assessed for laxity in 2 separate test sessions using the dynamic ultrasound technique., Results: Correlational analysis between the sonographic and radiographic measures revealed an r = 0.79 (r(2) = 0.62), indicating excellent criterion-related validity for the sonographic imaging method. Test-retest repeatability was 0.72 and 0.85 for anterior and posterior translation, respectively, and interrater repeatability was 0.96 and 0.99 for anterior and posterior translation, respectively., Conclusions: Dynamic ultrasound appears to be a valid and repeatable method for assessing glenohumeral laxity in a clinical setting., Clinical Relevance: Based on the results of this study, dynamic ultrasound is a repeatable and valid method for measuring glenohumeral laxity and therefore may be used as a viable replacement for stress radiography during assessments of glenohumeral laxity.

The rotator interval and the long head of the biceps brachii tendon are anatomically closely associated structures believed to confer stability to the shoulder joint. Abnormalities of the rotator interval may be acquired or congenital and are associated with instability of the long head of the biceps brachii tendon. Clinical and arthroscopic diagnoses of rotator interval abnormalities and subtle instability patterns of the long head of the biceps brachii tendon are difficult. Magnetic resonance arthrography, owing to its superior depiction of ligaments with distention of the joint capsule, may be the procedure of choice, barring open surgery, for help in diagnosis of these conditions., ((c) RSNA, 2005.)

Objective: The purpose of this research was to describe the sonographic findings of pectoralis major injuries with clinical, surgical, and magnetic resonance imaging (MRI) correlation., Methods: Images from sonographic examinations of the pectoralis major muscle of 6 patients were retrospectively evaluated and characterized. The sonographic findings were compared with clinical, surgical, and MRI findings., Results: The 6 patients were male (mean age, 30 years) with injuries sustained during weight lifting, football, and shotgun firing. Two of the 6 patients had MRI correlation; 1 had surgical correlation; 2 had both surgical and MRI correlation; and 1 had clinical follow-up. The sternal head was injured in 5 patients; 4 involved the musculotendinous junction, and 1 involved the distal tendon. The sonographic findings of muscle fiber retraction and surrounding hemorrhage allowed identification of the affected muscle. Direct impact injury causing hematoma involved the clavicular head in 1 patient. In total, 5 cases were partial-thickness pectoralis major tears, whereas complete distal tendon disruption was found in 1., Conclusions: Sonographic imaging longitudinal to the pectoralis muscle fibers showed fiber disruption, retraction, and possible hypoechoic or anechoic hematoma, most commonly involving the musculotendinous junction of the sternal head. Distal tendon assessment is important to evaluate for a full-thickness pectoralis major tear.

Rationale and Objectives: One mission of an academic radiology department is to teach. The greatest teaching effort is directed at radiology residents. As clinical work demands increase, informal, non-revenue-generating, teaching may suffer. We sought to determine the economic consequences of teaching., Materials and Methods: With the use of a picture archiving and communications system, 6 radiology faculty members independently interpreted and dictated digitally acquired bone and chest radiographs for 1 hour alone and again 10-12 weeks later with a first-year resident. During the second session, the quality of teaching was graded by independent observers. The number of cases, relative value units (RVUs), and reimbursement for each session were calculated., Results: The difference in number of cases dictated working alone (mean, 44.7) and with a first-year resident (mean, 23.5) was significant (P = 0.007). The difference between RVUs generated by faculty alone (mean, 9.0) and with a resident (mean, 4.5) also was significant (P = 0.006), and the difference in dollars billed when working alone (mean, $1558.45) and with a resident (mean, $777.65) was significant (P = 0.007). As teaching quality increased, the number of cases interpreted, dollars billed, and RVUs trended lower., Conclusion: Informal resident teaching significantly reduces clinical throughput, reducing examination volume, RVUs, and dollars billed by approximately half.

Purpose: To retrospectively determine the accuracy of sonography in helping to distinguish soft-tissue lipomas from other soft-tissue masses by using histologic proof as the reference standard., Materials and Methods: Institutional review board approval was obtained, and informed consent was waived. Thirty-nine patients who underwent sonographic evaluation of a soft-tissue mass followed by biopsy or resection were retrospectively evaluated. Two musculoskeletal radiologists (readers 1 and 2) reviewed the sonographic images, characterized the masses, and rated the level of confidence in the diagnosis of lipoma by using a five-point scale. A level of confidence was also rated for the prospective sonographic report, which was reviewed and designated as reader 3. Receiver operating characteristic (ROC) curves, including 95% confidence intervals, were generated, and the area under the ROC curve (A(z)) was calculated for each reader. Sensitivity, specificity, and accuracy for each reader were calculated by using a confidence rating of 4 or 5 as positive for lipoma. Weighted kappa analysis was also performed to assess for interobserver variability., Results: Histologic examination yielded 25 lipomas and 14 nonlipomas. The echogenicity of lipomas ranged from hypoechoic to hyperechoic relative to muscle, although most were isoechoic or hyperechoic. A(z) values were 0.79 for reader 1, 0.56 for reader 2, and 0.77 for reader 3. There was no significant difference between the A(z) for each reader and for chance. Interobserver agreement was fair, with a kappa value of 0.35 among the three readers. Sensitivities were 52%, 40%, and 52%, and accuracies were 64%, 49%, and 64% for readers 1, 2, and 3, respectively., Conclusion: Sonography demonstrates low accuracy in the diagnosis of soft-tissue lipomas., ((c) RSNA, 2004.)

Obese individuals have slowed conduction in the median nerve across the wrist, but the mechanism for this is not established. This case-control study of 27 obese subjects and 16 thin subjects was designed to test the hypothesis that obese individuals have higher carpal canal pressures and more median nerve swelling than thin individuals. All subjects were asymptomatic for hand symptoms, and had measurements of median and ulnar sensory nerve conduction in the nondominant hand, ultrasound measurement of the median nerve cross-sectional area proximal to the carpal canal, and carpal canal pressure measurement. There was no difference in age or gender ratio between the obese and thin groups. The median nerve cross-sectional area was equal in the obese and thin groups (9.3 mm2 vs. 9.4 mm2), as was the carpal canal pressure (16.2 mmHg vs. 15.5 mmHg, respectively). There was a strong correlation between median nerve conduction slowing across the wrist and median nerve cross-sectional area at the wrist (r = 0.55, P = 0.002). Obesity does not influence carpal canal pressure or the size of the median nerve at the wrist. However, there is a strong association between slowed median nerve conduction and increased nerve size which suggests endoneurial edema as a metabolic mechanism; the conduction slowing does not appear to be related to mechanical stress.

Objective: We have found variability in the sonographic appearance of peripheral nerve sheath tumors. The purpose of this study was to characterize the sonographic appearances of pathologically proven peripheral nerve sheath tumors., Conclusion: Peripheral nerve sheath tumors are often hypoechoic with posterior acoustic enhancement and so may simulate a ganglion cyst. The presence of intrinsic blood flow on color Doppler sonography and peripheral nerve continuity suggests the diagnosis of peripheral nerve sheath tumor. Sonography cannot reliably distinguish neurofibromas from schwannomas.

Objective: The object of this study was to determine the effectiveness of sonography in the detection of hip joint effusions in both native and postoperative adult hips using arthrocentesis as a gold standard., Materials and Methods: Twenty-one consecutive patients with clinical suspicion of hip joint effusion were examined on sonography by one of five musculoskeletal radiologists with experience in musculoskeletal sonography. All 21 patients underwent diagnostic arthrocentesis (fluoroscopic in 16, sonographic in five) to confirm the presence or absence of joint effusion. A retrospective analysis of the sonograms was made to assess the size of the distention of the anterior joint recess (anteroposterior dimension) and the echogenicity (anechoic or other relative to muscle), and correlation was made to the presence or absence of joint effusion., Results: Joint effusion was seen on diagnostic arthrocentesis in 10 (48%) of the 21 patients. Seven of the 21 patients had native hips and 14 had prior hip surgery. Retrospectively, no significant difference was found with regard to the size of the anterior recess distention (p = 0.34) or echogenicity (p = 0.2) when comparing the patients with and without joint effusion., Conclusion: Anterior recess distention and echogenicity could not reliably be used as an indicator of adult hip joint effusion, either in native or postoperative hips. Diagnostic arthrocentesis was necessary to establish or exclude the presence of hip joint effusion.

Purpose: To evaluate and characterize the use of sonography in imaging the posterolateral structures of the knee in human cadavers., Type of Study: In vitro laboratory investigation using human cadavers and sonography., Methods: Three cadaver knees were dissected to expose the posterolateral corner with the skin and subcutaneous tissue removed. The iliotibial band, biceps femoris muscle and tendon, lateral gastrocnemius tendon, the lateral collateral ligament, the popliteus tendon, the popliteofibular ligament, the arcuate ligament, and the fabellofibular ligament (when present) were identified. Following the soft tissue dissection, sonography was performed to characterize these structures. The technique was refined using this "open" examination method as anatomical and structural detail was noted. After adequate familiarization with this technique, researchers performed sonography on 2 pairs of thawed fresh-frozen cadaver knees, 1 pair with a fabella and 1 pair without a fabella. After sonographic examination of all of the posterolateral structures, the knees were dissected and the structures previously identified by sonography were verified., Results: In all 4 cadaver specimens, all posterolateral structures were identified based on their imaging characteristics and surrounding bony and soft tissue landmarks. We also present dissection photographs and sonographic images depicting our study findings., Conclusions: Sonographic imaging may provide the clinician with valuable information regarding the posterolateral structures of the knee. To our knowledge, this is the first study to investigate the sonographic findings of these structures. This technique may assist the physician evaluating these injuries and help in preoperative planning for repair or reconstructive procedures. Further research is needed to determine the accuracy of sonography in identifying injured posterolateral corner knee structures in vivo.

Objective: This report describes sonography of ankle tendon impingement due to osteophytes, fracture fragments, and orthopedic hardware., Conclusion: Sonography can be helpful in identifying ankle tendon impingement due to osteophytes, fracture fragments, and orthopedic hardware. In such cases, dynamic sonography can aid assessment.

Objective: The objective of our study was to sonographically characterize the dorsal aspect of the scapholunate ligament in cadaveric wrists using arthrography, MR arthrography, and anatomic correlation as the gold standard., Materials and Methods: The dorsal aspect of the scapholunate ligament in four cadaveric wrists was evaluated on sonography without knowledge of the findings from standard arthrography, MR arthrography, and anatomic sectioning. The sonographic findings were compared with the findings from other modalities. The criteria for an abnormal scapholunate ligament included an abnormal contrast communication between the radiocarpal and midcarpal joints on arthrography and a discontinuity of the dorsal aspect of the scapholunate ligament that was documented both on MR arthrography and at anatomic sectioning., Results: Arthrography, MR arthrography, and anatomic sectioning showed the dorsal aspect of the scapholunate ligament to be normal in one specimen and abnormal in three specimens. On sonography, the normal scapholunate ligament was hyperechoic between the scaphoid and lunate bones. In the three cases of abnormality, a normal scapholunate ligament was not visualized, and an abnormal hypoechogenicity was present., Conclusion: The dorsal aspect of the scapholunate ligament can be depicted on sonography; abnormality is present in patients in whom the normally hyperechoic fibrillar ligament is hypoechoic or absent.

Objective: We describe the sonographic imaging characteristics of ankle ganglia with pathologic correlation in 10 patients., Conclusion: Foot and ankle ganglia exhibit a spectrum of sonographic appearances from round and completely anechoic masses to hypoechoic, multilobulated, multiseptated masses with dependent debris. All the ganglionic cysts examined in our study showed posterior acoustic enhancement without solid nodules on sonography.