Imaging findings in cardiac tamponade with emphasis on CT.

Cardiac tamponade is a life-threatening condition that results from slow or rapid heart compression secondary to accumulation of fluid, pus, blood, gas, or tissue within the pericardial cavity. This condition can be associated with multiple causes including trauma, inflammation, scarring, or neoplastic involvement of the pericardial space among others. The main pathophysiologic event leading to tamponade is an increase in intrapericardial pressure sufficient to compress the heart with resultant hemodynamic impairment, which leads to limited cardiac inflow, decreased stroke volume, and reduced blood pressure. These events result in diminished cardiac output, which manifests clinically as a distinctive form of cardiogenic shock. Although cardiac tamponade is a clinical diagnosis, imaging studies play an important role in assessment and possible therapeutic intervention. Computed tomographic (CT) findings associated with cardiac tamponade include pericardial effusion, usually large, with distention of the superior and inferior venae cavae; reflux of contrast material into the azygos vein and inferior vena cava; deformity and compression of the cardiac chambers and other intrapericardial structures; and angulation or bowing of the interventricular septum. Familiarity with the clinical and pathophysiologic features of cardiac tamponade and correlation with the associated CT findings are essential for early and accurate diagnosis.

Thoracic manifestations of tropical parasitic infections: a pictorial review.

Parasitic infections are distributed worldwide and affect hundreds of millions of individuals-primarily those living in endemic areas or in regions with a high rate of immigration from endemic areas-causing significant morbidity and mortality. A broad spectrum of parasitic infections (eg, amebiasis, malaria, trypanosomiasis, ascariasis, strongyloidiasis, dirofilariasis, cystic echinococcosis, schistosomiasis, paragonimiasis) frequently affect the lungs, mediastinum, and thoracic wall, manifesting with abnormal imaging findings that often make diagnosis challenging. Although most of these infections result in nonspecific abnormalities, familiarity with their imaging features as well as their epidemiologic, clinical, and physiopathologic characteristics may be helpful to the radiologist in formulating an adequate differential diagnosis.

Imaging findings in musculoskeletal complications of AIDS.

Patients with human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) are susceptible to a variety of complications that can affect the musculoskeletal system. These complications can be infectious, inflammatory, or neoplastic or can take some other form. Infection (cellulitis, necrotizing fasciitis, soft-tissue abscess, pyomyositis, osteomyelitis, septic arthritis) is the most common complication. Inflammatory processes include various arthritides as well as polymyositis. Non-Hodgkin lymphoma and Kaposi sarcoma are the two most common neoplasms in this patient population. Miscellaneous disorders include osteonecrosis, osteoporosis, rhabdomyolysis, anemia-related abnormal bone marrow, and hypertrophic osteoarthropathy. The underlying mechanisms leading to these diseases are complex and not fully understood but are thought to be multifactorial. Radiology may play an important role in early diagnosis and treatment planning in this population, in whom clinical and laboratory findings are commonly equivocal and nonspecific. Although biopsy is often necessary for the final diagnosis, it is important for the radiologist to be familiar with the different types of musculoskeletal disease in HIV-positive and AIDS patients so that an appropriate differential diagnosis can be established.