Yoav Morag

Sonography of Inguinal Region Hernias

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.

Ultrasound of the Shoulder: Asymptomatic Findings in Men

OBJECTIVE The purpose of this study was to examine the range and prevalence of asymp tomatic findings at sonography of the shoulder. MATERIALS AND METHODS The study sample comprised 51 consecutively enrolled subjects who had no symptoms in either shoulder. Ultrasound of one shoulder per patient was performed by a musculoskeletal sonographer according to a defined protocol that included imaging of the rotator cuff, tendon of the long head of the biceps brachii muscle, subacromial-subdeltoid bursa, acromioclavicular joint, and posterior labrum. The shoulder imaged was determined at random. The 51 scans were retrospectively analyzed by three fellowship-trained musculoskeletal radiologists in consensus, and pathologic findings were recorded. Subtle or questionable findings of mild tendinosis, bursal prominence, and mild osteoarthritis were not recorded. RESULTS Twenty-five right and 26 left shoulders were imaged. The subject age range was 40-70 years. Ultrasound showed subacromial-subdeltoid bursal thickening in 78% (40/51) of the subjects, acromioclavicular joint osteoarthritis in 65% (33/51), supraspinatus tendinosis in 39% (20/51), subscapularis tendinosis in 25% (13/51), partial-thickness tear of the bursal side of the supraspinatus tendon in 22% (11/51), and posterior glenoid labral abnormality in 14% (7/51). All other findings had a prevalence of 10% or less. CONCLUSION Asymptomatic shoulder abnormalities were found in 96% of the subjects. The most common were subacromial-subdeltoid bursal thickening, acromioclavicular joint osteoarthritis, and supraspinatus tendinosis. Ultrasound findings should be interpreted closely with clinical findings to determine the cause of symptoms.

Bisphosphonate-related Osteonecrosis of the Jaw: A Pictorial Review

Bisphosphonate-related osteonecrosis of the jaw (ONJ) is characterized by nonhealing exposed bone in the maxillofacial region in patients who have undergone bisphosphonate treatment. The underlying etiology is unclear and may be multifactorial. The diagnosis is primarily clinical. Diagnostic tissue sampling may exacerbate the process and is typically avoided, necessitating other diagnostic approaches. The appearance of ONJ at diagnostic imaging is variable and includes sclerotic, lytic, or mixed lesions with possible periosteal reaction, pathologic fractures, and extension to soft tissues. There is a spectrum of signal intensity changes on T1- and T2-weighted magnetic resonance (MR) images with variable enhancement, findings that may correspond to the clinical and histopathologic stage of the process. Bone scintigraphy is sensitive with increased uptake in the area of the lesion. Although the imaging findings are nonspecific, there appears to be a role for imaging in the management of ONJ. Radiography is relatively insensitive but typically employed as the first line of radiologic investigation. Computed tomography and MR imaging are more precise in demonstrating the extent of the lesion. A number of imaging modalities have revealed lesions that may be associated with bisphosphonate exposure in asymptomatic individuals or in the context of nonspecific symptoms. The risk of these lesions advancing to overt clinical disease is unknown at this time. The radiologist should be aware of ONJ and include it in the differential diagnosis when evaluating patients with a history of bisphosphonate therapy without jaw irradiation, so as to avoid potentially harmful biopsies.

Sonography of Morel-Lavallée Lesions

Objective. The purpose of this series was to retrospectively characterize the sonographic appearance of posttraumatic Morel‐Lavallée lesions. Methods. After Institutional Review Board approval was obtained, a search of the radiology information system database with correlation to medical records identified 21 posttraumatic fluid collections of the hip and thigh in 15 patients. Sonographic images were retrospectively reviewed by 1 author to characterize the echogenicity, homogeneity, shape, margins, location, compressibility, and vascularity of the fluid collection. Results were correlated with the age of the fluid collection and aspiration results where possible. Results. All fluid collections (21/21) were located between the deep fat and fascia, with a shape that was fusiform in 12 (60%) of 20, flat in 5 (25%), and lobular in 3 (15%) (shape not determined in 1 case). Regarding echogenicity, 15 (71%) of the 21 collections were hypoechoic, and 6 (29%) were anechoic; 13 (62%) were heterogeneous, and 8 (38%) were homogeneous. The lobular fluid collections were all less than 2 weeks of age, and the flat fluid collections were all greater than 6 months of age. All homogeneous fluid collections were greater than 8 months of age. There was no relationship between the age of a fluid collection and its echogenicity. Conclusions. Morel‐Lavallée lesions had a variable appearance, being more homogeneous and flat or fusiform in shape with a well‐defined margin as the lesions aged. All Morel‐Lavallée lesions were hypoechoic or anechoic, compressible, and located between the deep fat and overlying fascia.

Lisfranc Joint Displacement Following Sequential Ligament Sectioning

BACKGROUND There are two primary radiographic patterns of Lisfranc instability, transverse and longitudinal. There is no single diagnostic method with which to consistently confirm the diagnosis of an unstable injury. Our purpose was to define which ligament disruptions produce these two injury patterns and to compare the utility of weight-bearing and stress radiographs for detecting each pattern of instability. METHODS Ten fresh-frozen cadaveric lower extremities were dissected to expose the dorsal aspect of the midfoot. Radiographic markers were placed at the base of the second metatarsal and the distal borders of the first and second cuneiforms. The specimens underwent sectioning of the interosseous first cuneiform-second metatarsal (Lisfranc) ligament and were then divided into two groups. The transverse group underwent sectioning of the plantar ligament between the first cuneiform and the second and third metatarsals at the plantar aspect of the second cuneiform-second metatarsal joint, whereas the longitudinal group underwent sectioning of the interosseous ligament between the first and second cuneiforms. Weight-bearing, adduction, and abduction stress radiographs were made before and after each ligament was sectioned. The radiographs were digitized, and displacement was recorded. Instability was defined as >or=2 mm of displacement. RESULTS Weight-bearing radiographs made after the Lisfranc (first cuneiform-second metatarsal) ligament alone was sectioned were diagnostic (showed instability) for one of ten specimens. Abduction stress radiographs were diagnostic for two of five specimens, and adduction stress radiographs were diagnostic for zero of five specimens. In the transverse group (sectioning of the plantar ligament between the first cuneiform and the second and third metatarsals), weight-bearing radiographs were diagnostic on the basis of first cuneiform-second metatarsal displacement for one of five specimens but were not diagnostic on the basis of second cuneiform-second metatarsal displacement for any of five specimens. Abduction stress radiographs were diagnostic on the basis of displacement of both the first cuneiform-second metatarsal and the second cuneiform-second metatarsal joints for five of five specimens. In the longitudinal group (sectioning of the interosseous ligament between the first and second cuneiforms), weight-bearing radiographs were diagnostic on the basis of first cuneiform-second metatarsal displacement for one of five specimens and were diagnostic on the basis of displacement between the first and second cuneiforms for one of five specimens. Adduction stress radiographs were diagnostic on the basis of first cuneiform-second metatarsal displacement for one of five specimens and were diagnostic on the basis of displacement between the first and second cuneiforms for four of five specimens. CONCLUSIONS Transverse instability required sectioning of both the interosseous first cuneiform-second metatarsal ligament and the plantar ligament between the first cuneiform and the second and third metatarsals. Longitudinal instability required sectioning of both the interosseous first cuneiform-second metatarsal ligament and the interosseous ligament between the first and second cuneiforms. Compared with weight-bearing radiographs, injury-specific manual stress radiographs showed qualitatively greater displacement when used to evaluate both patterns of instability.

The subscapularis: anatomy, injury, and imaging

The subscapularis is the largest and most powerful of the rotator cuff muscles and fulfills an important role in glenohumeral movement and stability. The spectrum and implications of subscapularis muscle or tendon injury differ from injury to other rotator cuff components because of its unique structure and function. Diagnosing subscapularis injury is clinically difficult and assessment of subscapularis integrity may be limited during arthroscopy or open surgery. Diagnostic imaging plays an important part in diagnosing and evaluating the extent of subscapularis injury. The radiologist should be aware of the anatomy of the subscapularis, the variations in muscle or tendon injury, and the potential implications for treatment and prognosis.

Characteristic Locations of Inguinal Region and Anterior Abdominal Wall Hernias: Sonographic Appearances and Identification of Clinical Pitfalls

OBJECTIVE The purpose of this article is to show the typical locations of anterior abdominal wall and inguinal region hernias and to illustrate their sonographic appearances and describe pitfalls in clinical diagnosis of hernias that may be resolved with sonography. CONCLUSION Awareness of the expected locations of anterior abdominal wall hernias and potential clinical pitfalls allows an accurate diagnosis of a hernia and helps in differentiating a hernia from other abnormalities.

Classification of Common Acetabular Fractures: Radiographic and CT Appearances

OBJECTIVE Accurate characterization of acetabular fractures can be difficult because of the complex acetabular anatomy and the many fracture patterns. In this article, the five most common acetabular fractures are reviewed: both-column, T-shaped, transverse, transverse with posterior wall, and isolated posterior wall. Fracture patterns on radiography are correlated with CT, including multiplanar reconstruction and 3D surface rendering. CONCLUSION In the evaluation of the five most common acetabular fractures, assessment of the obturator ring, followed by the iliopectineal and ilioischial lines and iliac wing, for fracture allows accurate classification. CT is helpful in understanding the various fracture patterns.

Entrapment Neuropathies in the Upper and Lower Limbs: Anatomy and MRI Features

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.

Sonography of fat necrosis involving the extremity and torso with magnetic resonance imaging and histologic correlation.

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.