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Myriad infectious organisms can infect the endocardium, myocardium, and pericardium, including bacteria, fungi, parasites, and viruses. Significant cardiac infections are rare in the general population but are associated with high morbidity and mortality as well as increased risk in certain populations, such as the elderly, those undergoing cardiac instrumentation, and intravenous drug abusers. Diagnostic imaging of cardiac infections plays an important role despite its variable sensitivity and specificity, which are due in part to the nonspecific manifestations of the central inflammatory process of infection and the time of onset with respect to the time of imaging. The primary imaging modality remains echocardiography. However, cardiac computed tomography and magnetic resonance (MR) imaging have emerged as the modalities of choice wherever available, especially for diagnosis of complex infectious complications including abscesses, infected prosthetic material, central lines and instruments, and the cryptic manifestations of viral and parasitic diseases. MR imaging can provide functional, morphologic, and prognostic value in a single examination by allowing characterization of inflammatory changes from the acute to chronic stages, including edema and the patterns and extent of delayed gadolinium enhancement. We review the heterogeneous and diverse group of cardiac infections based on their site of primary cardiac involvement with emphasis on their cross-sectional imaging manifestations. Online supplemental material is available for this article. (©)RSNA, 2016.

Cystic lesions are commonly seen in the mediastinum, and they may arise from virtually any organ. The vast majority of these lesions are benign and result in no symptoms. When large, cysts may produce symptoms related to compression of adjacent structures. The most common mediastinal cysts are pericardial and foregut duplication cysts. Both computed tomography and magnetic resonance are routinely used to evaluate these lesions. Although computed tomography offers superior spatial resolution, magnetic resonance is useful in differentiating cysts that contain proteinaceous material from solid lesions. Occasionally, cysts arise from solid lesions, such as thymoma or teratoma. Although cysts are alike in appearance, location helps narrowing the differential diagnoses.

A wide variety of disorders can affect the trachea and central bronchi. Computed tomography is the imaging modality of choice in the evaluation of tracheobronchial disease. Tracheobronchial abnormalities are sometimes incidentally detected on routine imaging or when imaging is performed for another reason. Abnormalities of the tracheobronchial tree, however, can be easily missed because they can be subtle. Furthermore, because symptoms in patients with tracheobronchial disorders often overlap symptoms of lung disease, radiologists may focus their attention on the lungs and overlook the tracheobronchial tree. In this article, we review a wide range of tracheobronchial diseases with emphasis on their computed tomographic appearances.

Eosinophil-associated diseases (EADs) are a diverse group of disorders characterized by an increase in circulating or tissue eosinophils. Cardiopulmonary and gastrointestinal system involvement can be due to primary EAD with no known cause or can be secondary to known systemic disease. The cardiopulmonary spectrum of EADs comprises simple pulmonary eosinophilia, acute eosinophilic pneumonia, chronic eosinophilic pneumonia, Churg-Strauss syndrome, allergic bronchopulmonary aspergillosis, bronchocentric granulomatosis, parasitic infections, and idiopathic hypereosinophilic syndrome. Eosinophilic gastrointestinal disorders include eosinophilic esophagitis, eosinophilic gastroenteritis, and eosinophilic colitis. Diagnosis is often challenging and requires a combination of clinical and imaging features along with laboratory findings. The absolute eosinophil count in peripheral blood and the percentage of eosinophils in bronchoalveolar lavage fluid are crucial in evaluation of various eosinophilic lung diseases. Although chest radiography is the initial imaging modality used in suspected cases of pulmonary EAD, multidetector computed tomography may demonstrate more characteristic pulmonary patterns, nodules, and subtle parenchymal abnormalities. Barium esophagography is used to assess mucosal abnormalities and the length and diameter of esophageal strictures. Magnetic resonance imaging is superior in providing valuable information in select patients, especially in evaluation of cardiac and gastrointestinal system involvement. Many patients require a multimodality imaging approach to enable diagnosis, guide treatment, and assess treatment response. Knowledge of the clinical features and imaging findings of the spectrum of EADs involving the lungs, heart, and gastrointestinal tract permits optimal patient care.

Congenital anomalies of the pulmonary circulation can be seen as isolated anomalies or as part of more complex malformations affecting numerous organs and systems, in particular the lungs, heart, and great vessels. These malformations may affect the pulmonary arteries, pulmonary veins, the aorta, and the intrathoracic systemic veins. With its superb spatial and temporal resolution, contrast-enhanced multidetector CT has become the imaging modality of choice for the evaluation of these entities, allowing imaging of the heart, vasculature, and lungs in one single examination.

Congenital abnormalities may affect any segment of the thoracic aorta. Their clinical presentation is quite variable, and some may require prompt and precise diagnosis to avoid complications. Associated cardiovascular comorbidities are common, and their presence and type may significantly affect prognosis, management, and patient outcome. Nowadays, state-of-the-art multidetector computed tomography has replaced invasive angiography in the evaluation of patients with suspected aortic disease. With the advent of this technology that allows diagnostic scans even in small infants and newborns, radiologists must be familiar with anatomy and pathophysiology of these uncommon diseases. The embryology, morphology, and imaging findings of these anomalies, divided according to their anatomic location, are reviewed.

This review focuses on the embryology and anatomy of the aorta with some imaging examples. Dividing the aorta by segments of unique function and embryogenesis facilitates organizing the group of potential anomalies encountered. A basic understanding of the embryologic development of the aorta and its major branches helps in understanding and recognizing typical and atypical anatomic findings. Diagnostic imaging of the aorta and its major branches can be accomplished by invasive and noninvasive methods, based on the clinical scenario and the age of the patient. In this review, computed tomography and magnetic resonance imaging examples are emphasized.

Trauma is the leading cause of death in United States in the younger population. Cardiac trauma is common following blunt chest injuries and is associated with high morbidity and mortality. This study discusses various multidetector computed tomography (MDCT) findings of cardiac trauma. Cardiac injuries are broadly categorized into the most commonly occurring blunt cardiac injury and the less commonly occurring penetrating injury. Signs and symptoms of cardiac injury can be masked by the associated injuries. Each imaging modality including chest radiographs, echocardiography, magnetic resonance imaging and MDCT has role in evaluating these patients. However, MDCT is noninvasive; universally available and has a high spatial, contrast, and temporal resolution. It is a one stop shop to diagnose and evaluate complications of cardiac injury. MDCT is an imaging modality of choice to evaluate patients with cardiac injuries especially the injuries capable of causing hemodynamic instability.

Kaposi's sarcoma (KS), a low-grade malignancy that is associated with human herpesvirus-8 (HHV-8), is a multifocal tumor that most commonly affects mucocutaneous sites. It might also involve lymph nodes and visceral organs, in particular of the respiratory and gastrointestinal tract, but it can affect every organ system. Four forms of the disease have been recognized: the classic, the endemic, the transplant-associated, and the epidemic form. The endemic form, or African KS, currently accounts for 10%-50% of all cancers in adults and up to 25% of cancers in children in certain parts of Africa. The epidemic form or acquired immune deficiency syndrome (AIDS)-associated KS is a frequent neoplasm in bisexual and homosexual men with AIDS in the United States. Even though in North America and Europe the incidence of KS in men with AIDS has decreased significantly after the introduction of highly active antiretroviral therapy (HAART), in some developing countries, the incidence of KS keeps growing. The pathophysiology, clinical manifestations, imaging findings, and more relevant differential diagnoses are reviewed.

There is a wide pathological spectrum of kidney sarcomas that show characteristic histology, ontogeny, and clinical-biological behavior. While leiomyosarcomas commonly arise from the capsule, solitary fibrous tumors and clear cell sarcomas typically show renal sinus and medullary epicenter, respectively. Although distribution and imaging findings of some sarcomas may be characteristic, definitive diagnosis warrants histopathological examination following surgery. Renal sarcomas manifest advanced disease at presentation and portend poor prognosis.

Congenital pulmonary artery anomalies represent a diverse group of abnormalities, ranging from asymptomatic incidental findings to causes of sudden cardiac death. While some may be recognized in childhood, others may be found incidentally in adulthood. We review the clinical and imaging findings in patients with congenital anomalies of the pulmonary arteries, including valvular and perivavular anomalies as well as abnormal narrowing, course and communications of the pulmonary arteries. We also discuss the role of various imaging modalities in the evaluation of these patients. It is vital to be aware of the key radiologic manifestations and associated haemodynamic consequences in these conditions in order to facilitate accurate diagnosis and prognostic stratification.

Tricuspid stenosis in the setting of endocardial pacing leads is a rare entity, attributed to infection or lead malposition. We report the case of a 37-year-old man without these risk factors, who presented with new onset severe tricuspid stenosis in the setting of multiple chronic pacing leads. (PACE 2010; e49–e52)

Mediastinal hematomas are the end result of numerous conditions ranging from the deadly traumatic aortic injury to the common changes after open heart surgery. The location of the hematoma, its relation with the surrounding structures, the clinical history, and associated findings can help narrow the differential diagnosis. Contrast-enhanced computed tomography is the imaging modality of choice because of its accessibility, noninvasiveness, rapid acquisition, and ability to evaluate the entire thorax at once.

Cocaine is the second most commonly abused illicit drug in the US and the most common one involved in emergency department visits, the majority of which are related to the cardiovascular system. Cardiovascular complications related with cocaine abuse include myocardial ischemia and infarction, myocarditis, hypertrophic cardiomyopathy, dilated cardiomyopathy, aortic dissection, thrombosis, stroke and cerebral hemorrhage, and different forms of visceral ischemia, among others. In an era where cocaine use has reached epidemic proportions, it is necessary for the radiologist to understand the pathophysiology, clinical presentation, and imaging characteristics of its cardiovascular complications.

The retrocrural space (RCS) is a small triangular region within the most inferior posterior mediastinum bordered by the two diaphragmatic crura. Multiplanar imaging modalities such as computed tomography and magnetic resonance imaging allow evaluation of the RCS as part of routine examinations of the chest, abdomen, and spine. Normal structures within the retrocrural region include the aorta, nerves, the azygos and hemiazygos veins, the cisterna chyli with the thoracic duct, fat, and lymph nodes. There is a wide range of normal variants of the diaphragmatic crura and of structures within the RCS. Diverse pathologic processes can occur within this region, including benign tumors (lipoma, neurofibroma, lymphangioma), malignant tumors (sarcoma, neuroblastoma, metastases), vascular abnormalities (aortic aneurysm, hematoma, azygos and hemiazygos continuation of the inferior vena cava), and abscesses. An understanding of the anatomy, normal variants, and pathologic conditions of the diaphragmatic crura and retrocrural structures facilitates diagnosis of disease processes within this often overlooked anatomic compartment.

Intramural hematoma of the esophagus (IHE) is a rare but well-documented condition that is part of the spectrum of esophageal injuries which includes the more common Mallory-Weiss tear and Boerhaave's syndrome. Acute retrosternal or epigastric pain is a common clinical feature, which can be accompanied by dysphagia, odynophagia, or hematemesis. An early differentiation from Mallory-Weiss tear, Boerhaave syndrome, ruptured aortic aneurysm, aortic dissection, acute myocardial infarction, or pulmonary pathology can be difficult. Computed tomography (CT) is the imaging modality of choice and characteristically reveals a concentric or eccentric thickening of the esophageal wall with well-defined borders and variable degree of obliteration of the lumen. Measurement of the attenuation values within the lesion will reveal blood density which varies according to the age of the hematoma. CT should be considered the preferred diagnostic technique, thereby facilitating proper clinical management. Early diagnosis is crucial as most patients may be treated conservatively with good outcome.

Kaposi sarcoma (KS) of bone and skeletal muscle is unusual. In this report, the authors review 66 published patients with KS who had involvement of the musculoskeletal system reported from 1925 to 2006. In only 3 patients was acquired immunodeficiency syndrome (AIDS)-related KS identified within skeletal muscle. Osseous KS lesions were more frequent and occurred with African, classic, and AIDS-related KS and occurred rarely in transplantation-associated KS. Patients seldom were asymptomatic. They usually had bone pain with limited mobility or infrequently developed serious sequelae like spinal cord compression. Locally aggressive African and classic KS lesions typically involved the peripheral skeleton; whereas, in patients with AIDS, the axial (vertebrae, ribs, sternum, and pelvis) and/or maxillofacial bones more commonly were involved. Almost all patients had concomitant nonosseous KS lesions. Joint involvement was exceptional, and pathologic fractures were not observed. Computed tomography scans and magnetic resonance images were better at detecting osseous KS lesions, which frequently went undetected on plain x-ray films or bone scans. Pathologic diagnosis was important to exclude similar lesions like bacillary angiomatosis. Treatment options, including surgery and, in more recent patients, radiation and/or chemotherapy, had limited success.

A wide variety of fat-containing entities occur in and near the heart. These findings are often encountered by radiologists and may be incidental or the reason for the patient's clinical presentation. Cross-sectional imaging helps to characterize the extent of these lesions and to formulate a differential diagnosis, which varies by lesion location, imaging features and patient demographics. The purpose of this pictorial essay is to familiarize radiologists with these fat-containing lesions and to help avoid misdiagnosis and errors in management. This pictorial review will discuss the normal fatty structures in and around the heart. A range of common and uncommon fat-containing lesions will then be reviewed based upon lesion location.

Kaposi sarcoma (KS) is a low-grade vascular tumor that typically manifests as one of four variants: classic KS, endemic (African) KS, iatrogenic (organ transplant-related) KS, or acquired immunodeficiency syndrome (AIDS)-related KS. Several clinical and epidemiologic differences have been noted among these variants. Classic KS and endemic KS rarely require radiologic evaluation due to their usually chronic course and stability of skin compromise. However, iatrogenic KS and AIDS-related KS, the most common forms of the disease, are frequently disseminated or symptomatic and may thus require imaging studies for both diagnosis and staging. KS is the most common tumor among AIDS patients, affecting a high percentage of these individuals, and is considered to be an AIDS-defining illness. Multiple organs can be involved by AIDS-related KS. KS has been linked with human herpes virus type 8 infection and other cofactors. Although pulmonary, gastrointestinal, and skin involvement by KS has previously been described, this tumor can affect multiple organs, generating a wide spectrum of imaging findings and pathologic correlates. It is important for the radiologist to be familiar with this spectrum of imaging manifestations and corresponding pathologic findings.

The heart and great vessels are not the sites most frequently affected by opportunistic infections and neoplastic processes in patients with acquired immune deficiency syndrome (AIDS). However, cardiovascular complications occur in a significant number of such patients and are the immediate cause of death in some. The spectrum of cardiovascular complications of AIDS that may be depicted at imaging includes dilated cardiomyopathy, pericardial effusion, human immunodeficiency virus-associated pulmonary hypertension, endocarditis, thrombosis, embolism, vasculitis, coronary artery disease, aneurysm, and cardiac involvement in AIDS-related tumors. To aid accurate diagnosis and appropriate treatment planning, radiologists should be familiar with the imaging appearance of each of these complications.

Tracheal stenosis is a frequent problem that in most cases is a complication of prolonged intubation. When the stenosis impairs more than half of the length of the trachea, it is not technically feasible to make a resection with a terminoterminal anastomosis. 1 In this clinical context, tracheal transplantation is a therapeutic alternative. We report the case of a patient in whom a vascular-ized tracheal transplantation was performed successfully and emphasize the importance of an imaging evaluation, particularly with ultrasonography.

Neurofibromatosis type 1 (NF1) is an autosomal dominant congenital dysplasia of the neural crest cells that affects the development of tissue and structures arising from the 3 germinal layers. Affected patients may present with spinal deformities or with bone or soft tissue abnormalities. Imaging plays an important role in the evaluation of these patients. In this article, a working diagnosis approach is proposed and the spectrum of spinal imaging findings in the NF1 patient is reviewed.

This imaging review describes the appearance of benign cardiac tumors on CT and MRI. Although rare, benign tumors outnumber their primary malignant counterparts three to one. Since mortality varies directly with invasion, identifying the neoplasm at an early stage helps focus treatment, especially in benign cases, which generally respond well to surgical resection. In adults and children, myxomas and rhabdomyomas, respectively, represent the most common benign tumors, which can be grouped into tissue-specific subtypes, such as rhabdomyomas, fibromas, lipomas, teratomas, etc. Besides their variable prevalence in particular age groups, these tumors also differ with regard to their gender predilection, location, and number. For example, myxomas appear predominantly in women and generally as a solitary mass in the left or right atrium, whereas rhabdomyomas present equally in boys and girls and chiefly as multiple masses in the ventricles. Despite their differences, however, both types share an association with heritable syndromes like the Carney complex for myxomas and tuberous sclerosis for rhabdomyomas. As with all cardiac tumors, echocardiographic findings usually suggest the initial diagnosis but cross-sectional imaging with CT and MRI can help resolve diagnostically challenging cases. For example, with its direct multiplanar capability, excellent contrast resolution, and large field of view, MRI permits a detailed examination of the entire mediastinum, helping to rule out an equivocal mass on echocardiography. Through dynamic techniques, MRI, in addition to morphologic characterization, can depict the pathophysiological effects of these tumors, for instance, with regard to myocardial contraction, valvular function, or blood flow.

This article reviews CT and MRI features of malignant cardiac and pericardial tumors, most of which originate from the lung, breast, melanoma, leukemia, or lymphoma through lymphatic, hematogenous, transvenous, and direct pathways. Although echocardiography establishes the diagnosis in most cases, CT and MRI provide additional physical, spatial, and functional information that further aids the evaluation of metastases. For instance, CT provides superior resolution for detecting calcification or fat, while MRI with its direct multiplanar ability more completely characterizes the heart, pericardium, mediastinum, and lungs. MRI also helps elucidate the pathophysiological effects of these tumors on cardiac function through gated cine-loop sequences. Beyond tumor characterization, both modalities can help confirm diagnosis through the addition of contrast, which helps distinguish tumor from myocardium, thrombus, and blood flow artifact. Ultimately, MRI best facilitates surgical planning and posttreatment follow-up in large part because of its unparalleled ability to locate and delimit these tumors.

Paragangliomas are uncommon tumors that arise from the parasympathetic neuroectodermal ganglionic cells and have been described in numerous anatomic locations, most commonly in the abdomen. Head and neck paragangliomas are classified into carotid body (most common), vagal, and jugulotympanic types. Computed tomography is the initial imaging modality of choice for the preoperative assessment of the extent of paragangliomas. Magnetic resonance imaging and selective angiography provide more detail of the surrounding tissues and vasculature. Surgical resection is the treatment of choice.

Lymphoproliferative pulmonary neoplasms can occur as primary pulmonary lymphomas or because of secondary pulmonary involvement. Neoplastic disorders may be difficult to differentiate from reactive pulmonary lymphoproliferative disorders, and immunohistochemical evaluation is often required to differentiate the 2 types of lesions. Neoplastic lymphoproliferative disorders are monoclonal lesions. Most affected patients present with systemic complaints, and imaging findings typically include nodules, masses, and lymphadenopathy. Primary pulmonary lymphomas are rare and account for less than 4% of the lymphomas that arise in extranodal sites. Secondary pulmonary lymphomas can affect the lung via hematogenous dissemination or by secondary involvement from tumor in adjacent or contiguous sites. Neoplastic lymphoproliferative lesions also include leukemia and plasma cell neoplasms. Posttransplantation lymphoproliferative disorders constitute a special type of lymphoid proliferation occurring in the setting of the chronic immunosuppression required for solid organ and bone marrow transplantation.

Primary cardiac neoplasms are rare and identified in 0.05–0.15 % of cases in large autopsy [1, 2] and echocardiography series [3]. Primary cardiac tumors may be classified as benign or malignant. The most common benign cardiac tumors include myxoma, rhabdomyoma, fibroma, and lipoma, whereas the most common malignant primary tumors are sarcomas (angiosarcoma, fibrosarcoma, undifferentiated sarcoma, rhabdomyosarcoma) and lymphoma [4, 5]. The majority, about three-fourth, of these tumors are benign [1, 2]. Secondary involvement of the heart or pericardium through local invasion or metastatic spread of malignant tumors is at least 20 times more common, identified in about 1.2 % of autopsy cases [1, 2] and 8 % of cancer victims [6]. Thoracic tumors (e.g., lung, breast, and esophagus) commonly invade the pericardium and heart. Other tumors that tend to metastasize to the heart include melanoma, soft tissue sarcomas, and gastric, pancreatic, thyroid, renal, and hepatocellular carcinomas [2, 6]. Cardiac involvement in lymphoma and leukemia is also common [2, 6]. When analyzed by the frequency according to the histologic type of the primary tumor, melanoma is the malignancy that more often metastasizes to the heart (46 % in autopsy series), followed by germ cell tumors (38 %), leukemia, and lymphoma [7].

Acute life-threatening conditions in oncology patients may develop either because of underlying malignancy or as a complication from treatment. Oncologic emergencies can be categorized as metabolic, hematologic, and structural conditions. Metabolic and hematologic emergencies are mainly diagnosed on the basis of clinical and laboratory findings. Structural pathologic conditions that result in bleeding, mechanical compression, or obstruction to the hollow organs, such as the trachea and bowel loops, may first be suspected because of clinical findings, including decreasing hematocrit levels, difficulty in breathing, and abdominal pain; however, performance of imaging studies is critical for timely diagnosis and management. Life-threatening conditions of the central nervous system (such as cerebral herniation, carcinomatous meningitis, and spinal cord compression), thoracic emergent conditions (such as central airway obstruction, esophagorespiratory fistula, massive hemoptysis, pulmonary embolism, superior vena cava syndrome, and pericardial tamponade), and abdominopelvic emergencies (such as uncontrolled intraabdominal hemorrhage, bowel obstruction, intestinal perforation, bowel ischemia, intussusception, and urinary tract obstruction) can be definitively diagnosed on the basis of projectional or cross-sectional imaging findings in appropriate clinical scenarios. Select emergent conditions in cancer patients related to chemotherapy and radiation treatment, as well as iatrogenic emergencies secondary to either surgery or placement of central venous catheters, may also demonstrate characteristic findings at imaging studies. In addition, interventional procedures are of great help in the treatment of acute superior vena cava syndrome, massive hemoptysis, and uncontrolled intraabdominal hemorrhage. Radiologists should be aware of these select, "not to be missed" imaging findings of oncologic emergencies to make an accurate, timely diagnosis and provide appropriate patient care.

The pulmonary vasculature may be involved by different primary and secondary tumors. Poorly differentiated and undifferentiated sarcomas are the most common primary tumors of the pulmonary arteries. They tend to affect the large caliber pulmonary vessels and present with predominantly intraluminal growth. Pulmonary and mediastinal metastasis are common, and prognosis is poor. Clinical and imaging manifestations may mimic those of pulmonary embolism. Dyspnea, chest pain, cough, and hemoptysis are the most common presenting symptoms. Primary sarcomas arising from the central pulmonary veins are less common than their arterial counterpart. Secondary involvement of the pulmonary arteries and veins by primary and metastatic pulmonary malignancies is more common. Tumoral embolism may also affect the pulmonary arteries. They may develop from different intrathoracic and extrathoracic malignancies and may be indistinguishable from venous thromboembolism. It may manifest as cor pulmonale with right cardiac strain and dilated pulmonary arteries. Computed tomography, magnetic resonance imaging, and fluorodeoxyglucose positron emission tomography may help in the differentiation between these 2 conditions.

This review focuses on the embryology and normal imaging anatomy of the pulmonary circulation, with emphasis on the major arterial and venous vasculature. The pulmonary circulation and parenchyma have a complex intertwined embryologic origin. Understanding the embryologic basis of normal pulmonary vasculature aids recognition of anomalies and visceral situs in the chest. Adaptive changes to congenital anomalies of the pulmonary arterial vasculature are used to contrast from normal and review associated temporal adaptive vascular and parenchymal changes.

Increasing use of cross-sectional studies has resulted in a concomitant increase in the number of intravascular and perivascular masses found in patients being studied for a multitude of thoracic conditions. As a consequence, there needs to be an awareness of the imaging findings of certain unusual abnormalities that will help prevent erroneous treatment (eg, anticoagulation) and expedite proper therapy. Although the spectrum of conditions that may present as intravascular, mural, and extravascular abnormalities in and around the aorta is broad, imaging features like contrast enhancement, signal intensity, and metabolic activity may help in making the correct diagnosis. Examples of the imaging presentation of these rare primary tumors and more common secondary tumors that may affect the aorta are presented in this article.

"Aortitis" is a pathologic term that refers to an abnormal inflammation of the aortic wall. A wide spectrum of infectious, inflammatory, and idiopathic conditions may result in the development of aortitis. Infectious aortitis may be secondary to bacterial, tubercular, syphilitic, and viral pathogens. Although Takayasu arteritis and giant cell arteritis are the most common rheumatologic causes of aortitis, the other systemic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, Behcet disease, and Cogan syndrome, may also be associated with aortitis. In addition, aortitis may also occur without any systemic diseases or infectious causes (idiopathic). Clinical features of aortitis are nonspecific and may include fever, abdominal or chest pain, and vascular insufficiency. Patients may have elevated serum levels of acute phase reactants. A high index of clinical suspicion is always needed for the diagnosis of aortitis in a timely manner. Cross-sectional imaging techniques, such as computed tomographic angiography, magnetic resonance imaging, magnetic resonance angiography, and positron emission tomography, are extremely helpful in diagnosis, assessing disease activity, treatment planning, and post-treatment follow-up. Many of the patients with aortitis may require a multimodality imaging approach for appropriate diagnosis. Knowledge of the clinical features and cross-sectional imaging findings of different types of aortitis permit optimal patient management.

Nonthrombotic pulmonary embolism is defined as embolization to the pulmonary circulation caused by a wide range of substances of endogenous and exogenous biological and nonbiological origin and foreign bodies. It is an underestimated cause of acute and chronic embolism. Symptoms cover the entire spectrum from asymptomatic patients to sudden death. In addition to obstruction of the pulmonary vasculature there may be an inflammatory cascade that deteriorates vascular, pulmonary and cardiac function. In most cases the patient history and radiological imaging reveals the true nature of the patient's condition. The purpose of this article is to give the reader a survey on pathophysiology, typical clinical and radiological findings in different forms of nonthrombotic pulmonary embolism. The spectrum of forms presented here includes pulmonary embolism with biological materials (amniotic fluid, trophoblast material, endogenous tissue like bone and brain, fat, Echinococcus granulosus , septic emboli and tumor cells); nonbiological materials (cement, gas, iodinated oil, glue, metallic mercury, radiotracer, silicone, talc, cotton, and hyaluronic acid); and foreign bodies (lost intravascular objects, bullets, catheter fragments, intraoperative material, radioactive seeds, and ventriculoperitoneal shunts).

In the United States, trauma is the leading cause of death among those who are 1-44 years old, with cardiovascular injuries representing the second most common cause of traumatic death after central nervous system injuries. Evaluation of trauma patients with suspected cardiac injury may be complex and include electrocardiography, measurement of cardiac biomarkers, and imaging examinations. Contrast material-enhanced computed tomography (CT) has become one of the most valuable imaging tools available for evaluating hemodynamically stable patients with suspected cardiac injury. The presence of hemopericardium, with or without cardiac tamponade, is one of the most significant findings of cardiac injury. Other complications that result from blunt cardiac injury, such as pericardial rupture and cardiac herniation, may be readily depicted at multidetector CT. Assessment of patients with cardiac injuries, particularly those with penetrating injuries, is a challenging and time-critical matter, with clinical and imaging findings having complementary roles in the formation of an accurate diagnosis. Patients who are hemodynamically stable, particularly those with penetrating cardiac injuries, also may benefit from a timely imaging examination. In addition to chest radiography, other available modalities such as transthoracic and transesophageal echocardiography, nuclear medicine, and magnetic resonance imaging may play a role in selected cases.

Air-fluid levels within emphysematous lung bullae are a relatively uncommon occurrence in patients with preexisting bullous disease, and are not commonly reported. We report 2 cases of new onset air-fluid levels in patients with underlying bullous disease with substantially different clinical presentations but with clinical improvement after medical therapy only.

Given their high frequency, mediastinal emergencies are often perceived as being a result of external trauma or vascular conditions. However, there is a group of nonvascular, nontraumatic mediastinal emergencies that are less common in clinical practice, are less recognized, and that represent an important source of morbidity and mortality in patients. Nonvascular, nontraumatic mediastinal emergencies have several causes and result from different pathophysiologic mechanisms including infection, internal trauma, malignancy, and postoperative complications, and some may be idiopathic. Some conditions that lead to nonvascular, nontraumatic mediastinal emergencies include acute mediastinitis; esophageal emergencies such as intramural hematoma of the esophagus, Boerhaave syndrome, and acquired esophagorespiratory fistulas; spontaneous mediastinal hematoma; tension pneumomediastinum; and tension pneumopericardium. Although clinical findings of nonvascular, nontraumatic mediastinal emergencies may be nonspecific, imaging findings are often definitive. Awareness of various nonvascular, nontraumatic mediastinal emergencies and their clinical manifestations and imaging findings is crucial for making an accurate and timely diagnosis to facilitate appropriate patient management.

Aortitis is a general term that refers to a broad category of infectious or noninfectious conditions in which there is abnormal inflammation of the aortic wall. These inflammatory conditions have different clinical and morphologic features and variable prognoses. The clinical manifestations are usually vague and nonspecific and may include pain, fever, vascular insufficiency, and elevated levels of acute phase reactants, as well as other systemic manifestations. As a result, aortitis is often overlooked during the initial work-up of patients with constitutional symptoms and systemic disorders. A multimodality imaging approach is often required for assessment of both the aortic wall and aortic lumen, as well as for surveillance of disease activity and treatment planning. Noninvasive cross-sectional imaging modalities such as magnetic resonance (MR) imaging, MR angiography, and computed tomographic angiography play a critical role in initial evaluation and further assessment of aortitis. Radiologists should be familiar with the clinical features and imaging findings of the different types of aortitis.

Purpose To report our experience with the diagnosis and treatment of aortoiliac vascular injuries caused by misplaced orthopedic fixation screws. Materials Six patients (age range, 35-60 years; mean, 52 years) were diagnosed with seven arterial injuries related to misplacement of fixation screws. The location of the injuries were thoracic aorta (n = 4) and common iliac arteries (n = 3). There was vessel wall penetration in five injuries resulting in active bleeding in two patients, contained penetrations in two patients, and vessel occlusion in one patient. One patient had associated inferior vena cava injury and pulmonary embolism. Two patients had asymptomatic impingement of the aortic wall by the screws. Results Vascular injuries resulted in death in one patient and limb amputation in another patient. Three patients were treated with placement of stent grafts and screw removal. Screw replacement was performed in one patient. Conservative observation was done in one patient. Conclusions Vascular injuries related to misplacement of fixation screws are relatively infrequent but potential life and limb-threatening complications that require early recognition with prompt repair of vascular lesions and screw reposition.

Extracardiac nonsurgical vascular shunts in the thorax are a group of well-recognized heterogeneous conditions, frequently symptomatic, in which there is diversion of blood flow from one vessel to another or from a vessel to a cardiac chamber. The authors describe and classify many of these nonsurgical extracardiac shunts or fistulas according to their source and endpoint (eg, systemic-to-systemic, systemic-to-pulmonic, pulmonic-to-systemic, and pulmonic-to-pulmonic) and to whether the oxygenated blood mixes with deoxygenated systemic venous flow (left-to-right shunts), deoxygenated blood bypasses the pulmonary capillary bed (right-to-left shunts), or oxygenated blood recirculates (left-to-left shunts). Clinical manifestations and imaging appearances of these conditions are highlighted.

Tricuspid stenosis in the setting of endocardial pacing leads is a rare entity, attributed to infection or lead malposition. We report the case of a 37-year-old man without these risk factors, who presented with new onset severe tricuspid stenosis in the setting of multiple chronic pacing leads.

The sternum and sternoclavicular joints--critical structures of the anterior chest wall--may be affected by various anatomic anomalies and pathologic processes, some of which require treatment. Pectus excavatum and pectus carinatum are common congenital anomalies that are usually benign but may warrant surgical treatment if they cause compression of vital internal structures. By contrast, developmental variants such as the sternal foramen are asymptomatic and do not require further evaluation or treatment. Arthritides of the sternoclavicular joint (osteoarthritis, septic arthritis, and seronegative arthropathies) are common and must be differentiated before an appropriate management method can be selected. The recognition of complications of sternotomy (eg, sternal dehiscence, secondary osteomyelitis) is critical to avoid life-threatening sequelae such as acute mediastinitis. Likewise, the detection of sternal fractures and sternoclavicular dislocations is important, especially where they impinge on vital structures. In addition, sternal malignancies (most commonly, metastases and chondrosarcoma) must be distinguished from benign neoplasms. To achieve accurate and timely diagnoses that facilitate appropriate treatment, radiologists must be familiar with the appearances of these normal anatomic variants and diseases of the sternum.

A broad spectrum of parasitic infections frequently affects 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 and the diagnostic pathways help the radiologist to formulate an adequate differential diagnosis and to guide diagnosticians in reaching a definitive diagnosis.