Soft-tissue masses: optimal imaging protocol and reporting.

OBJECTIVE: Soft-tissue masses derive from a wide spectrum of tissues, and it may be difficult to differentiate nonneoplastic from neoplastic as well as benign from malignant lesions, to say nothing of making a single histologic diagnosis on the basis of imaging. The purpose of this article is to discuss optimal imaging protocols and reporting of soft-tissue masses. CONCLUSION: The radiologist should be prepared, if at all possible, to knowledgably examine the patient, optimize an imaging protocol, and differentiate among lesions. Specific features of an MRI examination must be discussed in each report to completely evaluate the mass and perform efficacious biopsy, staging, and eventual treatment of the lesion. Careful and systematic reporting of the examinations should avoid the devastating consequences of either overlooking a sarcoma or overtreating a benign lesion.

Low-grade cartilage tumors: diagnosis and treatment.

As a result of reading this article, physicians should be able to: 1. List the features that are useful in differentiating a low-grade chondrosarcoma from an enchondroma. 2. Describe the treatment principles of low-grade cartilage tumors based on the anatomic location and stage of the tumor. 3. Discuss the characteristics of a local recurrence after initial treatment and the general consequences.

Imaging of cartilage in the athlete.

Since the development of radiography, we have been able to visualize the osseous alterations related to arthritis. These include productive changes, such as osteophyte formation, sclerosis, and buttressing, as well as erosive changes and subchondral cyst formation. However, because cartilage is radiolucent, it is not directly visible by either radiography or computed tomography. With careful attention to technique, both hyaline and fibrocartilage can be visualized by magnetic resonance imaging.

From the RSNA Refresher Courses. Radiological Society of North America. Adult chronic hip pain: radiographic evaluation.

Adult chronic hip pain can be difficult to attribute to a specific cause, both clinically and radiographically. Yet, there are often subtle radiographic signs that point to traumatic, infectious, arthritic, neoplastic, congenital, or other causes. Stress fractures appear as a lucent line surrounded by sclerosis or as subtle lucency or sclerosis. Subtle femoral neck angulation, trabecular angulation, or a subcapital impaction line indicates an insufficiency fracture. Apophyseal avulsion fractures appear as a thin, crescentic, ossific opacity when viewed in tangent and as a subtle, disk-shaped opacity when viewed en face. Effusion, cartilage loss, and cortical bone destruction are diagnostic of a septic hip. Transient osteoporosis manifests as osteoporosis and effusion. The earliest finding of avascular necrosis is relative sclerosis in the femoral head. Subtle osteophytes or erosive change is indicative of arthropathy. Osteoarthritis can manifest as early cyst formation, small osteophytes, or buttressing of the femoral neck or calcar. Rheumatoid arthritis may manifest as classic osteopenia, uniform cartilage loss, and erosive change. A disturbance of the trabecular pattern might suggest an early permeative pattern due to a tumor. Knowledge of common causes of chronic hip pain will allow the radiologist to seek out these radiographic findings.

Neuropathic osteoarthropathy: diagnostic dilemmas and differential diagnosis.

The purpose of this pictorial essay is to illustrate the radiologic spectrum of imaging findings of neuropathic osteoarthropathy. Typical findings include joint destruction, disorganization, and effusion with osseous debris. A variety of other imaging findings related to neuropathic osteoarthropathy such as resorption of the ends of tubular bones and neuropathic fracture are shown. The two prevailing theories for the pathophysiology of neuropathic bone and joint disease, the neurovascular and neurotraumatic theories, are briefly described. Examples of osteoarthropathy from diverse causes are presented including syringomyelia, spinal cord injury, meningomyelocele, diabetes mellitus, congenital insensitivity to pain, steroid injections, syphilis, leprosy, and others. The discussion focuses on key imaging features with emphasis on disease patterns and differential diagnosis, which vary by skeletal location.

Abnormal signal intensity in skeletal muscle at MR imaging: patterns, pearls, and pitfalls.

Abnormal signal intensity within skeletal muscle is frequently encountered at magnetic resonance (MR) imaging. Potential causes are diverse, including traumatic, infectious, autoimmune, inflammatory, neoplastic, neurologic, and iatrogenic conditions. Alterations in muscle signal intensity seen in pathologic conditions usually fall into one of three recognizable patterns: muscle edema, fatty infiltration, and mass lesion. Muscle edema may be seen in polymyositis and dermatomyositis, mild injuries, infectious myositis, radiation therapy, subacute denervation, compartment syndrome, early myositis ossificans, rhabdomyolysis, and sickle cell crisis. Fatty infiltration may be seen in chronic denervation, in chronic disuse, as a late finding after a severe muscle injury or chronic tendon tear, and in corticosteroid use. The mass lesion pattern may be seen in neoplasms, intramuscular abscess, myonecrosis, traumatic injury, myositis ossificans, muscular sarcoidosis, and parasitic infection. Some of these conditions require prompt medical or surgical management, whereas others do not benefit from medical intervention. The ability to accurately diagnose these conditions is therefore necessary, and biopsy may be required to establish the correct diagnosis. Clues to the correct diagnosis and whether biopsy is necessary or appropriate are often present on the MR images, especially when they are correlated with clinical features and the findings from other imaging modalities.