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Leadership is much discussed but also often misunderstood. For radiologists, leadership may seem irrelevant or, even worse, an onerous addition to their busy careers. It is important that radiologists understand the relevance and importance of good leadership for the success of departments and groups. There are many obstacles to radiologists becoming effective leaders, including personal resistance that is due to myths and misunderstandings, the time and effort (and money) required to learn to lead well, as well as others including the shift in perspective that comes from focusing on organizational success rather than individual career success. This manifesto will explore the what, the why, and the how of becoming a leader in radiology and why it is critical for individuals, their organizations, academic departments, private practice groups, and others, as well as the larger house of radiology., (Copyright © 2018 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

The purpose of this series was to retrospectively characterize the ultrasound findings of delayed-onset muscle soreness (DOMS). The Institutional Review Board approved our study, and informed consent was waived. A retrospective search of radiology reports using the key phrase "delayed-onset muscle soreness" and key word "DOMS" from 2001 to 2015 and teaching files was completed to identify cases. The sonograms were reviewed by 3 fellowship-trained musculoskeletal radiologists by consensus. Sonograms were retrospectively characterized with respect to echogenicity (hypoechoic, isoechoic, or hyperechoic), distribution of muscle involvement, and intramuscular pattern (focal versus diffuse and well defined versus poorly defined). Images were also reviewed for muscle enlargement, fluid collection, muscle fiber disruption, and increased flow on color or power Doppler imaging. There were a total of 6 patients identified (5 male and 1 female). The average age was 22 years (range, 7-44 years). Of the 6 patients, there were a total of 11 affected muscles in 7 extremities (1 bilateral case). The involved muscles were in the upper extremity: triceps brachii in 27% (3 of 11), biceps brachii in 18% (2 of 11), brachialis in 18% (2 of 11), brachioradialis in 18% (2 of 11), infraspinatus in 9% (1 of 11), and deltoid in 9% (1 of 11). On ultrasound imaging, the abnormal muscle was hyperechoic in 100% (11 of 11), well defined in 73% (8 of 11), poorly defined in 27% (3 of 11), diffuse in 73% (8 of 11), and focal in 27% (3 of 11). Increased muscle size was found in 82% (9 of 11) and minimal hyperemia in 87.5% (7 of 8). The ultrasound findings of DOMS include hyperechoic involvement of an upper extremity muscle, most commonly appearing well defined and diffuse with increased muscle size and minimal hyperemia., (© 2016 by the American Institute of Ultrasound in Medicine.)

Objective: The purpose of this study was to describe the appearance and ultrasound characteristics of the Gruberi bursa using a cadaveric model and retrospective ultrasound imaging review., Materials and Methods: For the cadaveric study, ultrasound of the dorsolateral ankle of a foot-ankle specimen was performed and was followed by injection of latex between the extensor digitorum longus (EDL) tendons and the talus and dissection. For the ultrasound imaging review, the radiology database was searched for ultrasound studies performed from September 15, 2000, through April 1, 2015, to identify subjects with a dorsolateral foot or ankle fluid collection detected on ultrasound. Images were retrospectively reviewed to characterize the location and size of the fluid collection, assess for the number of locules, and evaluate the compressibility of the fluid collection. It was determined whether the ultrasound findings were significantly different from chance: CI and p values were obtained from performing a test for one proportion., Results: Dissection of a cadaveric specimen revealed latex within a well-defined region between the EDL tendons and the dorsolateral talus; this location is consistent with a Gruberi bursa. For the image review, the imaging examinations of 162 subjects (age range, 16-88 years; 31 male subjects and 131 female subjects) were reviewed. On the ultrasound images, a fluid collection with its epicenter between the dorsolateral talus and EDL was found in 93% of ankles. Of the fluid collections identified on ultrasound, 98% were unilocular and 94% were anechoic. Of these fluid collections, 133 were assessed for compressibility, and 89% were compressible. The positive findings for a Gruberi bursa that were different from chance (p < 0.0001) were a fluid collection being located between the EDL tendons and the dorsolateral talus and being unilocular, anechoic, and compressible., Conclusion: The Gruberi bursa characteristically is located between the EDL and the talus; on ultrasound, the Gruberi bursa is most commonly unilocular, anechoic, and compressible.

In a variety of injuries and illnesses, internal organs in the abdominal and pelvic regions, in particular liver, may be compromised. In the current practice, CT scans of liver are visually inspected to investigate the integrity of the organ. However, the size and complexity of the CT images limits the reliability of visual inspection to accurately assess the health of liver. Computer-aided image analysis can create fast and quantitative assessment of liver from the CT, in particular in the environments where access to skilled radiologists may be limited. In this paper we propose a hierarchical method based on probabilistic models of position and intensity of voxels for automated segmentation of liver that achieves the Dice similarity coefficient of higher than 89%.

Ultrasonography (US) is commonly used to assess the peripheral nerves of the lower extremity because of its many advantages over magnetic resonance (MR) imaging. The most obvious advantages over MR imaging are superior soft-tissue resolution, low cost, portability, lack of magnetic susceptibility artifact, and the ability to image patients who cannot undergo MR imaging. US has been shown to have equal specificity and greater sensitivity than MR imaging in the evaluation of peripheral nerves. Additional benefits are the capability of real-time and dynamic imaging, and the ability to scan an entire extremity quickly without the need for a patient to lie motionless for long periods of time, as with MR imaging. Any abnormal findings can be easily compared against the contralateral side. Published literature has shown that US has clinical utility in patients suspected of having peripheral nerve disease: US can be used to guide diagnostic and therapeutic decisions, as well as help confirm electrodiagnostic findings. Common indications for lower extremity peripheral nerve US are the evaluation for injury due to penetrating trauma, entrapment by scar tissue, or tumor. To confidently perform US of the peripheral nerves of the lower extremity, it is important to gain a thorough knowledge of anatomic landmarks and the course of each nerve. Readers who may not be familiar with US will be introduced to the basics of scanning the peripheral nerves of the lower extremity. Important anatomic landmarks and common sites of injury and entrapment will be reviewed., ((©)RSNA, 2016.)

Objective: Patients who undergo knee MRI for presumed musculoskeletal disease can have unexpected vascular findings or pathology in the imaged field. Some vascular processes are limb threatening and affect treatment planning and patient outcome., Conclusion: Unexpected vascular findings on knee MRI can range from incidental to symptomatic and can include such processes as variant anatomy, aneurysm, traumatic injury, and neoplasm. The assessment for vascular pathology should be a key component of every radiologist's search pattern when evaluating knee MRI.

Objective: Ultrasound of the thigh presents unique challenges because of the size and length of multiple structures, including tendons, muscles, nerves, and vessels. Those performing ultrasound can use a focal approach, a comprehensive approach, or a compartmental and flexible approach., Conclusion: This article illustrates and summarizes our approach to ultrasound of the thigh, including unique anatomy, artifacts, and common abnormalities, with an emphasis on the advantages of performing a compartment-based and flexible ultrasound examination.

Anatomic variations in the anterior aspect of the shoulder, such as an accessory head of the biceps brachii muscle, are not uncommon. The magnetic resonance imaging and arthroscopic appearance of the accessory head of the biceps brachii has been recently described. This series demonstrates the sonographic appearance of the accessory head of the biceps brachii in the bicipital groove. It is an asymptomatic, flat, echogenic structure with average measurements of 7.7 × 1.2 mm in cross section. Knowledge of this anatomic variant can avoid the misdiagnosis of a longitudinal split tear and improve the accuracy of sonography., (© 2014 by the American Institute of Ultrasound in Medicine.)

Objective: The ulnar collateral ligament (UCL) serves an important role in stabilizing the thumb metacarpophalangeal (MCP) joint. The adductor pollicis aponeurosis lies superficial to the UCL, and plays an important role in the pattern of injury and treatment of UCL tears. Ultrasound is a cost-effective and accurate method to evaluate the UCL, allowing dynamic imaging and contralateral comparison in the setting of acute injury. The purpose of this video article is to show the optimal technique for sonographic evaluation of the UCL., Conclusion: UCL tears are common injuries involving the base of the thumb, and correct diagnosis of a Stener lesion aids in timely surgical management. Performing ultrasound evaluation in the long axis with use of dynamic imaging allows excellent visualization of the UCL and adductor pollicis aponeurosis. With application of appropriate technique, ultrasound is highly accurate in diagnosing Stener lesions.

Objective: The purpose of this article is to illustrate and discuss the value of ultra-sound screening before joint aspiration., Conclusion: Before joint aspiration, ultrasound assessment of the overlying and surrounding soft tissues requires little time and is relatively inexpensive. Bursal fluid collections, soft-tissue abscesses, and other fluid collections that would be undetected with fluoroscopy or blind aspiration can thus be identified. Ultrasound screening before joint aspiration can aid diagnosis and decrease the risk of iatrogenic complications.

Objective: The purpose of this study was to determine the accuracy of ultrasound for distinguishing complete rupture of the distal biceps tendon versus partial tear and versus a normal biceps tendon. Surgical findings were used as the reference standard in cases of tear. Clinical follow-up was used to assess the normal tendons., Materials and Methods: The study population consisted of 45 consecutive elbow ultrasound cases with surgical confirmation and six cases of a clinically normal distal biceps tendon that underwent elbow ultrasound for suspicion of injury to a structure other than the biceps tendon. Cases underwent consensus review by two fellowship-trained musculoskeletal radiologists. Tendons were classified as normal biceps tendon, partial tear, or complete tear. The presence or absence of posterior acoustic shadowing at the distal biceps tendon was also assessed. The ultrasound findings were then compared with the surgical findings and clinical follow-up., Results: Ultrasound showed 95% sensitivity, 71% specificity, and 91% accuracy for the diagnosis of complete versus partial distal biceps tendon tears. Posterior acoustic shadowing at the distal biceps had sensitivity of 97% and accuracy of 91% for indicating complete tear versus partial tear and sensitivity of 97%, specificity of 100%, and accuracy of 98% for indicating complete tear versus normal tendon., Conclusion: Ultrasound can play a role in the diagnosis of elbow injuries when a distal biceps brachii tendon tear is suspected.

Deep fibromatoses, or desmoid tumors, arise from connective tissue. Imaging can frequently suggest the diagnosis of these aggressive, benign neoplasms. Cross-sectional imaging commonly demonstrates an enhancing solid mass that resembles scar tissue, typically without osseous involvement. We report a case of an extra-abdominal desmoid tumor involving the teres minor muscle in a symptomatic 42-year-old woman with unusual features of medullary involvement and negative nuclear beta-catenin staining.

Peripheral nerve entrapment occurs at specific anatomic locations. Familiarity with the anatomy and the magnetic resonance imaging (MRI) features of nerve entrapment syndromes is important for accurate diagnosis and early treatment of entrapment neuropathies. The purpose of this paper is to illustrate the normal anatomy of peripheral nerves in the upper and lower limbs and to review the MRI features of common disorders affecting the peripheral nerves, both compressive/entrapment and noncompressive, involving the suprascapular nerve, the axillary nerve, the radial nerve, the ulnar nerve, and the median verve in the upper limb and the sciatic nerve, the common peroneal nerve, the tibial nerve, and the interdigital nerves in the lower limb.

Objectives: The purpose of this study was to retrospectively characterize the sonographic appearance of partial-thickness distal triceps brachii tendon tears., Methods: After Institutional Review Board approval, sonographic records were searched for patients who had an unequivocal partial-thickness triceps tendon tear at surgery or magnetic resonance imaging. Sonograms were retrospectively characterized for tendon discontinuity of the superficial or deep layers, tendon retraction, osseous fracture fragments, and joint effusion. Imaging findings were then compared with clinical, imaging, and surgical results., Results: Five patients had a partial-thickness distal triceps brachii tendon tear at surgery (n = 4) or magnetic resonance imaging (n = 1). All cases only involved the superficial tendon layer (combined long and lateral heads) with retraction of a fractured olecranon enthesophyte fragment. The deep tendon layer (medial head) was intact in all cases with no joint effusion., Conclusions: Partial-thickness distal triceps brachii tendon tears have a characteristic appearance with selective superficial tendon retraction and olecranon enthesophyte avulsion fracture.

The purpose of this pictorial essay is to show the sonographic appearances of benign masses found in and around the elbow, including fat-containing tumors, fibrous tumors, vascular lesions, selected skin lesions, and other miscellaneous lesions. Sonographic features, including the use of dynamic and color Doppler imaging, can be helpful in characterizing these masses and in narrowing the differential diagnosis.

Several entrapment neuropathies of the upper extremity can cause hypoechoic swelling and nerve compression as seen at ultrasound. The ulnar nerve can be compressed at the cubital tunnel of the elbow and Guyon's canal at the wrist. The deep branch of the radial nerve can be compressed at the supinator muscle at the elbow, and the superficial radial nerve may be compressed at the dorsal wrist (Wartenberg's syndrome). In addition to compression at the carpal tunnel, the median nerve may be compressed at the elbow, related to a supracondylar process or by the pronator teres. Knowledge of these key anatomical sites of potential nerve compression is essential for accurate diagnosis of entrapment neuropathies., (© Thieme Medical Publishers.)

Objective: The purpose of this study was to determine if there are imaging and clinical findings that can differentiate a septic sternoclavicular joint from a degenerative one., Materials and Methods: Search of radiology reports from 2000-2007 revealed 460 subjects with imaging of the sternoclavicular joint, of whom 38 had undergone aspiration or biopsy. The final study group consisted of nine subjects with pathologic proof of sternoclavicular joint infection and ten subjects with pathologic and clinical findings excluding infection consistent with degenerative change. Available ultrasound, computed tomography (CT), and magnetic resonance (MR) images were retrospectively reviewed, and echogenicity, capsular distention, erosions, cysts, hyperemia or enhancement, and intensity of bone marrow signal were recorded. Clinical data were also reviewed., Findings: The findings significantly associated with sternoclavicular joint infection included degree and extent of capsular distention. With infection, average joint distention was 14 mm (range 10-20 mm) and extended over the sternum and clavicle in 60% compared to 5 mm (range 3-8 mm) with degeneration only extending over the clavicle. Other findings significantly associated with infection included bone marrow fluid signal on magnetic resonance imaging (MRI), elevated Westergren red blood cell sedimentation rate, and fever. The two findings significantly associated with degeneration were subchondral cysts on CT and female gender. Other imaging and clinical variables showed no significant differences between infection and degenerative change., Conclusion: The clinical and imaging findings significantly associated with sternoclavicular joint infection included joint capsule distention of 10 mm or greater, extension over both the clavicle and sternum, adjacent fluid signal bone marrow replacement, elevated Westergren red blood cell sedimentation rate, and fever.

Objective: This study characterized the sonographic appearances of Lisfranc injuries., Methods: Sonography reports (2000-2007) were searched for "Lisfranc," resulting in 10 patients. Sonographic images of affected and asymptomatic contralateral feet were reviewed, recording the thickness of the dorsal ligament between the first (medial) cuneiform (C1) and second metatarsal (M2) ligaments, distance between C1 and M2, and change in this distance with weight bearing, hyperemia, and fractures. Correlations were made to clinical, surgical, and other imaging findings., Results: In 5 asymptomatic feet, the dorsal C1-M2 ligament was 0.9 to 1.2 mm thick, and the C1-M2 distance was 0.5 to 1 mm. Of the symptomatic feet, 1 group (n=3) had normal sonographic findings (thickness, 0.9-1.1 mm; distance, 0.6-0.7 mm; all had normal radiographic findings and follow-up, and 1 had normal magnetic resonance imaging [MRI] findings). Another group (n=3) had abnormal hypoechogenicity and thickening of the dorsal C1-M2 ligament (1.4-2.3 mm), a normal C1-M2 distance (0.6-0.7 mm), and no widening with weight bearing (1 of 1), consistent with a ligament sprain (1 had normal computed tomographic [CT] findings, and all had uneventful follow-up). The third group (n=4) had nonvisualization of the dorsal C1-M2 ligament, an increased C1-M2 distance of 2.5 to 3.1 mm, and further widening with weight bearing (3 of 4) from Lisfranc ligament disruption (shown at surgery in 2, MRI in 1, and CT in 1)., Conclusions: Nonvisualization of the dorsal C1-M2 ligament and a C1-M2 distance of 2.5 mm or greater were indirect signs of a Lisfranc ligament tear. Dynamic evaluation with weight bearing showed widening of the space between C1 and M2.

Objective: The purpose of this study was to describe the sonographic appearance of pathologically proven isolated fat necrosis involving the extremities or torso with magnetic resonance imaging (MRI) correlation., Methods: A query of the Department of Pathology database at our institution for the diagnosis of fat necrosis resulted in 1539 cases. Review of the cases and medical records excluded cases without sonographic imaging, those involving the breast, and those within or adjacent to a primary process, including masses or prior surgery, which resulted in a total of 5 cases of primary fat necrosis, 2 of which were evaluated with MRI. Sonograms were reviewed by 2 musculoskeletal radiologists and characterized with regard to location, echogenicity, shadowing, posterior through-transmission, a hypoechoic rim or halo, definition of borders, homogeneity, a mass effect, and vascularity. The patient medical records, histologic results, and MRI findings were also reviewed., Results: Of the 5 cases of isolated fat necrosis, 2 involved the torso and 3 the lower extremities. On sonography, all were located in the subcutaneous fat; 2 were isoechoic; 3 were hyperechoic; 2 had a hypoechoic halo; none showed shadowing or posterior through-transmission; 2 were well defined; 3 were masslike; 4 were heterogeneous; and 2 showed increased flow on color or power Doppler imaging. Magnetic resonance imaging showed an intermediate signal and either diffuse or ring enhancement., Conclusions: Isolated fat necrosis of the extremities and torso had 2 sonographic appearances, which included a well-defined isoechoic mass with a hypoechoic halo and a poorly defined hyperechoic region in the subcutaneous fat.

Ultrasound has demonstrated great utility and accuracy for imaging the hindfoot and midfoot. Its advantages include its capacity to allow evaluation during dynamic maneuvers, imaging of patients who cannot undergo MR imaging, and real-time evaluation of the symptomatic site. It can also reveal abnormalities that are not apparent during static imaging. This article makes the case that radiologists should continue to be experts in all aspects of musculoskeletal imaging, including ultrasound or the business will be taken over by other specialties. If musculoskeletal ultrasound is lost, additional modalities such as MR imaging may be lost as well. Radiologists, with their expertise and years of training, are uniquely suited to apply this versatile modality to foot and ankle 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)

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.)

Objective: With the use of surgical findings as the reference standard, the purpose of this study was to describe the sonographic findings of partial-thickness and complete tears of the quadriceps tendon and to determine whether sonography can potentially aid diagnosis., Methods: Three hundred eighty-nine consecutive sonographic reports (January 1996 to April 2001) of the knee/quadriceps tendon were reviewed retrospectively and assessed for subsequent surgery on the quadriceps tendon. Seven cases were thus identified. Findings at surgery (complete versus partial tears) were compared with the original sonography reports., Results: All 4 partial tears and 1 of 2 complete tears were diagnosed correctly on the basis of sonography. One complete tear was described as a partial tear on the basis of sonography. In a seventh case, complete disruption of the extensor mechanism with osseous avulsion of the superior pole of the patella was identified correctly. Dynamic scanning was essential in diagnosing a partial quadriceps tendon tear in 1 case., Conclusions: Sonography, including the use of dynamic evaluation, was helpful in the diagnosis of partial-thickness tears of the quadriceps tendon and may aid in differentiation of such cases from complete quadriceps tendon tears, particularly in the acute setting. The presence of scar tissue in the setting of chronic injury may represent a potential pit-fall in the assessment of partial versus complete quadriceps tears. Further study is needed to define the accuracy of sonography for detecting quadriceps tendon tears.

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.

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: 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.

Initial experience with the use of dynamic sonography of the elbow for diagnosing ulnar nerve dislocation and snapping triceps syndrome is reported. Cases of three consecutive patients who underwent sonographic evaluation of the elbow and subsequent open elbow surgery for symptomatic ulnar nerve dislocation were reviewed. Dynamic sonography of the elbow was used to aid in the accurate diagnosis of and differentiation between ulnar nerve dislocation and snapping of the medial triceps muscle.

Ultrasonography (US) allows detection of a variety of soft-tissue foreign bodies, including wood splinters, glass, metal, and plastic, along with evaluation of their associated soft-tissue complications. Cases were obtained from the authors' clinical experience over the past 1.5 years. Surgical correlation allowed confirmation of the presence of a foreign body and associated soft-tissue complications in all cases. All of the foreign bodies were echogenic when imaged with US. A surrounding hypoechoic rim and posterior acoustic shadowing or reverberation aided detection in several cases. Associated soft-tissue complications included a complete laceration of the posterior tibial tendon and septic flexor digitorum tenosynovitis. US allows accurate and efficient detection of radiolucent soft-tissue foreign bodies and aids assessment of their associated complications. For radiopaque foreign bodies, US can provide more precise localization and improved assessment of the surrounding soft tissues. US has emerged as the study of choice for detection and localization of radiolucent soft-tissue foreign bodies and can aid assessment of their associated complications.

Purpose: To determine the accuracy of the use of sonography for differentiation of full- from partial-thickness tears or tendinosis of the Achilles tendon by using surgical findings as the standard of reference and to identify sonographic characteristics of full-thickness tears that can be used to differentiate the two types of tears., Materials and Methods: In part A of this study, sonographic findings (based on reports) in 26 consecutive cases of tears of the Achilles tendon were compared with surgical findings. In part B, the sonograms were blindly and retrospectively evaluated with respect to six sonographic characteristics possibly related to pathologic findings in the tendon, and the characteristics were correlated with surgical findings., Results: In part A, statistical data regarding the use of sonographic findings to distinguish full- from partial-thickness tears were as follows: sensitivity, 100%; specificity, 83%; accuracy, 92%; positive predictive value, 88%; and negative predictive value, 100%. In part B, tendon thickness (P <.001), posterior acoustic shadowing (P =.007), and tendon retraction (P <.001) were correlated with full-thickness tears. Visualization of fat herniation (P =.051) and of the plantaris tendon (P =.098) demonstrated marginal correlation with full-thickness tears. Echogenicity at the site of the pathologic finding in the tendon showed no significant correlation., Conclusion: Sonography can be used to differentiate full- from partial-thickness tears or tendinosis of the Achilles tendon with 92% accuracy. Undetectable tendon at the site of injury, tendon retraction, and posterior acoustic shadowing demonstrate statistically significant correlation with full-thickness tears.

Objective: The objective of this study was to assess the ability of sonography to reveal Baker's cysts using MR imaging as a gold standard., Materials and Methods: The study group consisted of 36 consecutive knees in 36 patients evaluated with both MR imaging and sonography. Inclusion criteria included axial proton density-weighted or T2-weighted MR images, a sonography report that documented the evaluation of the popliteal region of the knee, and sonographic and MR images that were available for review. The MR images were retrospectively reviewed for the presence of Baker's cyst (fluid signal between the semimembranosus and medial gastrocnemius tendons). Sonography reports were compared with the MR imaging results. The sonographic images were also retrospectively reviewed to determine whether any characteristic findings on sonography were significantly associated with the presence of Baker's cyst on MR imaging., Results: Retrospective review of MR images revealed 21 Baker's cysts, one myxoid liposarcoma, one meniscal cyst, and 13 examinations with normal findings. The sonography reports revealed that the 21 Baker's cysts were correctly diagnosed, whereas the meniscal cyst and myxoid liposarcoma were misdiagnosed as Baker's cysts. Retrospective review of sonographic images showed a 100% sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in the diagnosis of Baker's cyst when hypoechoic or anechoic fluid was present between the semimembranosus and medial gastrocnemius tendons. No other sonographic characteristics were significant., Conclusion: Identification of fluid between the semimembranosus and medial gastrocnemius tendons in communication with a posterior knee cyst indicates Baker's cyst with 100% accuracy.

Purpose: To evaluate the sonographic appearance of the peroneus quartus muscle., Materials and Methods: Thirty-two consecutive patients who underwent both sonography and magnetic resonance (MR) imaging of the lateral ankle were retrospectively identified during 42 months. Seven of these patients demonstrated a peroneus quartus muscle, with MR imaging as the standard of reference. The peroneus quartus muscle was characterized at retrospective review of sonographic images with regard to origin, insertion, echogenicity, and location., Results: Of the seven peroneus quartus muscles, six originated from the peroneus brevis muscle, and all seven inserted onto the calcaneus. The muscle portion of the peroneus quartus muscle was hypoechoic, while the tendon portion was hyperechoic and fibrillar. The location of the peroneus quartus musculotendinous junction was variable. Hence, the appearance of the peroneus quartus muscle in the region of the distal fibula ranged from 100% muscle to 100% tendon., Conclusion: Variability in the appearance of the peroneus quartus muscle is common with sonography due to variation in the location of the musculotendinous junction. Recognition of these variations will allow correct diagnosis of a peroneus quartus muscle, and more important, it will allow differentiation from adjacent tendon abnormality.