Normal Magnetic Resonance Imaging Anatomy of the Capsular Ligamentous Supporting Structures of the Knee.

Recognition of the normal magnetic resonance (MR) imaging appearances of the capsular ligaments of the knee is of great importance. These ligaments contribute to stability of the knee joint and are frequently injured. In this article, we describe the normal MR imaging anatomy of the capsular ligaments of the knee including the lateral and medial collateral ligamentous complexes, the extensor mechanism, and the supporting ligamentous structures of the proximal tibiofibular joint. Normal MR imaging findings and important anatomic variants of the neurovascular structures of the knee are also described.

High-Resolution US of Rheumatologic Diseases.

For the past 15 years, high-resolution ultrasonography (US) is being routinely and increasingly used for initial evaluation and treatment follow-up of rheumatologic diseases. This imaging technique is performed by using high-frequency linear transducers and has proved to be a powerful diagnostic tool in evaluation of articular erosions, simple and complex joint and bursal effusions, tendon sheath effusions, and synovitis, with results comparable to those of magnetic resonance imaging, excluding detection of bone marrow edema. Crystal deposition diseases including gouty arthropathy and calcium pyrophosphate deposition disease (CPPD) have characteristic appearances at US, enabling differentiation between these two diseases and from inflammatory arthropathies. Enthesopathy, which frequently accompanies psoriatic and reactive arthritis, also has a characteristic appearance at high-resolution US, distinguishing these two entities from other inflammatory and metabolic arthropathies. The presence of Doppler signal in examined joints, bursae, and tendon sheaths indicates active synovitis. Microbubble echo contrast agents augment detection of tissue vascularity and may act in the future as a drug delivery vehicle. Frequently, joint, tendon sheath, and bursal fluid aspirations and therapeutic injections are performed under US guidance. The authors describe the high-resolution US technique including gray-scale, color or power Doppler, and contrast agent-enhanced US that is used in evaluation of rheumatologic diseases of the wrist and hand and the ankle and foot in their routine clinical practice. This article demonstrates imaging findings of normal joints, rheumatoid arthritis, gouty arthritis, CPPD, psoriatic and reactive arthritis, and osteoarthritis.

Multiligamentous injuries and knee dislocations.

Complex capsular ligamentous structures contribute to stability of the knee joint. Simultaneous injury of two or more knee ligaments, aside from concurrent tears involving the anterior cruciate and medial collateral ligaments, is considered to be associated with femorotibial knee dislocations. Proximal tibiofibular joint dislocations are not always easily recognized and may be overlooked or missed. Patellofemoral dislocations can be transient with MR imaging sometimes required to reach the diagnosis. In this article, the authors describe the mechanism of injury, ligamentous disruptions, imaging, and treatment options of various types of knee dislocations including injuries of the femorotibial, proximal tibiofibular, and patellofemoral joints.

Imaging and management of thumb carpometacarpal joint osteoarthritis.

Primary osteoarthritis (OA) involving the thumb carpometacarpal (CMC) joint is a common and frequently debilitating disease. Clinical examination and radiographs are usually sufficient for diagnosis; however, familiarity with the cross-sectional anatomy is useful for diagnosis of this condition. The most widely used classification system for the radiographic staging of thumb carpometacarpal joint OA was first presented by Eaton and Littler, ranging from mild (stages I and II) to severe (stage IV) disease. If conservative treatment fails, surgical treatment is considered. A variety of surgical techniques have been developed and implemented for the management of this pervasive and disabling condition. The purpose of this article is to review the anatomy of the basal joints of the thumb, pathophysiology, preoperative imaging, and various surgical techniques that are utilized in the treatment of OA of the basal joints of the thumb with emphasis on normal postoperative radiographic findings and possible postoperative complications.

Spectrum of carpal dislocations and fracture-dislocations: imaging and management.

OBJECTIVE: The objectives of this article are to discuss the imaging of carpal dislocations and fracture-dislocations and to review the ligamentous anatomy of the wrist, mechanisms of injury, and routine management of these injuries. CONCLUSION: Perilunate dislocations, perilunate fracture-dislocations (PLFDs), and lunate dislocations are high-energy wrist injuries that can and should be recognized on radio-graphs. These injuries are a result of important sequential osseous and ligamentous injuries or failures. Prompt and accurate radiographic diagnosis aids in the management of patients with perilunate dislocations, PLFDs, and lunate dislocations while assisting orthopedic surgeons with subsequent surgical planning. CT may better show the extent of the injury and help in treatment planning particularly in cases of delayed treatment or chronic perilunate dislocation. A CT examination with coronal, sagittal, and 3D reformatted images is ordered at our institution in cases in which the extent of the carpal injuries is poorly shown on radiographic examination.

RSNA Centennial Article: Gone but Not Completely forgotten­ pictorial review of "antiquated" radiologic procedures [corrected].

The field of diagnostic and therapeutic radiology has always been characterized by constant innovation and creativity to evolve to its current form. There are numerous imaging techniques that were once prevalent but have become outdated and were replaced by the current examinations and modalities, which improve diagnostic accuracy and patient outcomes. Many of these outdated examinations were first described in the journal Radiology during its first 100 years of existence and were subsequently able to be disseminated across its vast readership to become the standard of care across the nation and the world. These earlier techniques, such as pneumoencephalography as it applies to neuroimaging and neurosurgery; kymography, a predecessor of cardiac imaging; contrast agents such as Thorotrast; and miscellaneous cultural tools, such as the shoe-fitting fluoroscope, left lasting impressions on the current practice of radiology and reflect a small subset of the imaging examinations of our predecessors. Knowledge of historic radiologic examinations and procedures is important to understand how we have arrived at the current practice of radiology we embrace today and how our field can continue to evolve to improve our diagnostic and therapeutic abilities to fit the changing needs of our patients.

Artifacts in musculoskeletal ultrasonography.

During the past 2 decades, high-resolution ultrasonography (US) has been increasingly utilized in the diagnosis of musculoskeletal trauma and diseases with results comparable with MR imaging. US has an advantage over other cross-sectional modalities in many circumstances due to its superior spatial resolution and ability to allow dynamic assessment. When performing musculoskeletal US, the examiner has to be knowledgeable in the complex anatomy of the musculoskeletal system and US imaging technique. Additionally, he or she must be familiar with several common imaging artifacts in musculoskeletal US that may be mistaken for pathology, as well as several artifacts that frequently accompany pathologic conditions. These artifacts may occur with both B-mode gray-scale and Doppler imaging. In this article, we discuss common artifacts seen in musculoskeletal US and techniques to avoid or minimize these artifacts during clinical US examinations.

The athlete's hand: ligament and tendon injury.

Hand injuries are common, accounting for up to 20% of emergency department visits nationwide. An understanding of the complex and detailed anatomical relationships of small joints facilitates the accurate diagnosis of many common sports-related injuries of the hand. We review the common ligamentous and tendinous injuries of the hand including collateral ligament injuries, gamekeeper's thumb, extensor mechanism injuries, pulley injuries, boutonniere deformities, and mallet and jersey lesions. The mechanism of injury, clinical presentation and treatment, pertinent anatomy, and imaging findings are discussed.

Paget sarcoma of the pelvic bone with widespread metastatic disease on radiography, CT, MRI, and 18F-FDG PET/CT with pathologic correlation.

We report a case of Paget sarcoma of the left superior pubic ramus and disseminated metastatic disease in a 70-year-old man. Paget disease of the left hemipelvis with malignant degeneration in the region of the left superior pubic ramus was initially diagnosed on radiographs. Subsequent CT, MRI, PET/CT imaging, and CT-guided biopsy confirmed the diagnosis and showed extensive left-sided pelvic and abdominal lymphadenopathy with widespread metastatic disease to liver, spleen, and lungs.

Radiology-pathology conference: primary perinephric and renal extraosseous Ewing's sarcoma.

Ewing's sarcoma/primitive neuroectodermal tumor is a rare entity belonging to a family of neoplasms of neuroectodermal origin. These highly aggressive neoplasms overwhelmingly affect children and young adults. A quarter of Ewing's sarcomas occur principally in the soft tissues with primary involvement of the perinephric fat and kidney being exceptionally rare. We present a 38-year-old man with primary Ewing's sarcoma of the perinephric fat and kidney diagnosed 2 years earlier who subsequently developed an infiltrating left renal and perinephric mass.

Radiologic-pathologic findings of primary osseous adamantinoma with unusual metastasis to the posterior cul-de-sac in pregnancy.

Adamantinoma is a rare primary bone malignancy with a predilection for the tibial cortex. Metastases have been reported to the long bones, lung, pleura and spine. We present a 26-year-old pregnant woman with metastatic disease to the posterior cul-de-sac, lungs, liver and retroperitoneum, which collectively have not been previously reported in a single patient to our knowledge.

Progression of clinically stable lymphedema on lymphoscintigraphy.

Lymphedema is due to dysfunction in lymphatic transport, and is divided into primary and secondary subtypes. Primary lymphedema is a congenital lymphatic abnormality or dysfunction whereas secondary lymphedema is characterized by pathologic disruption or obstruction of a previously-normal lymphatic system. The stage of lymphedema is determined clinically. Lymphoscintigraphy, however, may be used to assess disease extent, for early detection of disease progression, and can be used to direct therapy. We report a case of a 56-year-old woman with clinically stable lymphedema of 5 years, yet with lymphoscintigraphy findings compatible with disease progression.

Primary testicular lymphoma involving the spermatic cord and gonadal vein.

We report a case of a 70-year-old man with a history of prostatic adenocarcinoma and a 3-month history of right hemiscrotal swelling. The patient underwent a CT scan, scrotal ultrasound, and F-18 FDG-PET scan to evaluate for metastatic prostate cancer. The CT scan demonstrated an ill-defined soft-tissue mass extending along the right gonadal vein. Scrotal ultrasound revealed a heterogeneous right testicular mass. The F-18 FDG-PET scan demonstrated intense hypermetabolic activity along the course of the right gonadal vein extending to the right hemiscrotum. Subsequent right radical orchiectomy and pathologic examination revealed a B-cell lymphoma, infiltrating the testicular parenchyma, spermatic cord, gonadal vessels, and adjacent soft-tissues. Lymphoma or other tumors rarely infiltrate the spermatic cord, and have only very rarely been demonstrated on PET imaging.

Cutaneous and subcutaneous imaging on FDG-PET: benign and malignant findings.

F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) has been shown to be useful in the evaluation of many tumors due to its high sensitivity and specificity. However, false-positive interpretations may occur from benign subcutaneous and cutaneous etiologies. At our institution we have encountered FDG-PET scans which demonstrated a variety of cutaneous and subcutaneous lesions including stomas, hernias, rhinophyma, dose infiltrations, physiologic muscle uptake, and tophaceous gout. Additionally, malignant cutaneous and subcutaneous malignant lesions may also demonstrate substantial F-18 FDG uptake on PET scans, including lymphoma, skin metastases, and melanoma. The purpose of this atlas article is to demonstrate and review key features of various cutaneous and subcutaneous lesions, both benign and malignant, which can result in hypermetabolism on FDG-PET or PET-CT scans.