Diego Lemos - Academia.edu (original) (raw)

Papers by Diego Lemos

Research paper thumbnail of Appearance of the delta phalanx (longitudinally bracketed epiphysis) with MR imaging

Pediatric Radiology, 2011

The delta phalanx is an unusual condition occurring in the hand or the foot that can be distingui... more The delta phalanx is an unusual condition occurring in the hand or the foot that can be distinguished from a secondary ossification center on radiographic evaluation based on the well-defined phalangeal epiphyses typically evident by 24–30 months of age. MR imaging of the delta phalanx offers the advantage of visualizing sites of unossified bone before the age these findings are typically visible with radiography. We describe the case of a 15-month-old boy who presented with soft-tissue fusion of the third and fourth digits of the right hand. Radiograph and MR evaluation revealed soft-tissue intra-axial syndactyly of the third and fourth digits and a delta phalanx involving the proximal phalanx of the involved fourth digit.

Research paper thumbnail of CT and MR imaging findings of malignant cardiac tumors

Current Problems in Diagnostic Radiology, 2005

This article reviews CT and MRI features of malignant cardiac and pericardial tumors, most of whi... more 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.

Research paper thumbnail of Association of two respiratory congenital anomalies: tracheal diverticulum and cystic adenomatoid malformation of the lung

Pediatric Radiology, 2004

Many associations of congenital anomalies of the respiratory system have been reported, but the c... more Many associations of congenital anomalies of the respiratory system have been reported, but the combination of tracheal diverticulum and cystic adenomatoid malformation (CCAM) is unique. We present a patient with these two anomalies and analyze their embryological correlation.

Research paper thumbnail of CT and MR imaging findings of benign cardiac tumors

Current Problems in Diagnostic Radiology, 2005

This imaging review describes the appearance of benign cardiac tumors on CT and MRI. Although rar... more 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.

Research paper thumbnail of Imaging findings of expansile lesions of the thymus

Current Problems in Diagnostic Radiology, 2005

The purpose of this article is to review the imaging findings of the different expansile lesions ... more The purpose of this article is to review the imaging findings of the different expansile lesions of the thymus. Almost 50% of all mediastinal masses are located in the anterior mediastinum. The thymus is the most common site of origin of these masses. Several kinds of lesions can arise from this gland because it derives from the three embryonic germ cell layers. Primary neoplasms of the thymus are thymoma, thymolipomas, carcinoma, carcinoid, primary germ cell tumors, and lymphoma. The latter can also involve the organ in a secondary fashion. Other lesions that cause thymic enlargement and that can be confused with neoplasia are thymic cysts and thymic hyperplasia. Even though anterior mediastinal masses are first found on conventional radiographs, computed tomography and magnetic resonance are very useful additional studies for assessing the origin and extension of these masses. The basic concepts regarding embryology, anatomy, and histology relevant for the differential diagnosis of an enlarged thymic gland are also described.

Research paper thumbnail of Imaging Findings in Musculoskeletal Complications of AIDS

Radiographics, 2004

Patients with human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome... more 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.

Research paper thumbnail of Imaging Manifestations of Kaposi Sarcoma

Radiographics, 2006

Kaposi sarcoma (KS) is a low-grade vascular tumor that typically manifests as one of four variant... more 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.

Research paper thumbnail of Imaging Findings in Cardiac Tamponade with Emphasis on CT

Radiographics, 2007

Cardiac tamponade is a life-threatening condition that results from slow or rapid heart compressi... more 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.

Research paper thumbnail of Intramural hematoma of the esophagus: a pictorial essay

Emergency Radiology, 2008

Intramural hematoma of the esophagus (IHE) is a rare but well-documented condition that is part o... more 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 maybe treated conservatively with good outcome.

Research paper thumbnail of Imaging Appearances of the Sternum and Sternoclavicular Joints1

Radiographics, 2009

The sternum and sternoclavicular joints--critical structures of the anterior chest wall--may be a... more 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.

Research paper thumbnail of The Diaphragmatic Crura and Retrocrural Space: Normal Imaging Appearance, Variants, and Pathologic Conditions1

Radiographics, 2008

The retrocrural space (RCS) is a small triangular region within the most inferior posterior media... more 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.

Research paper thumbnail of Cardiovascular Complications of Human Immunodeficiency Virus Infection

Radiographics, 2006

The heart and great vessels are not the sites most frequently affected by opportunistic infection... more 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.

Research paper thumbnail of CT and MR imaging findings of malignant cardiac tumors

Current Problems in Diagnostic Radiology, 2005

This article reviews CT and MRI features of malignant cardiac and pericardial tumors, most of whi... more 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.

Research paper thumbnail of Association of two respiratory congenital anomalies: tracheal diverticulum and cystic adenomatoid malformation of the lung

Pediatric Radiology, 2004

Many associations of congenital anomalies of the respiratory system have been reported, but the c... more Many associations of congenital anomalies of the respiratory system have been reported, but the combination of tracheal diverticulum and cystic adenomatoid malformation (CCAM) is unique. We present a patient with these two anomalies and analyze their embryological correlation.

Research paper thumbnail of CT and MR imaging findings of benign cardiac tumors

Current Problems in Diagnostic Radiology, 2005

This imaging review describes the appearance of benign cardiac tumors on CT and MRI. Although rar... more 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.

Research paper thumbnail of Imaging findings of expansile lesions of the thymus

Current Problems in Diagnostic Radiology, 2005

The purpose of this article is to review the imaging findings of the different expansile lesions ... more The purpose of this article is to review the imaging findings of the different expansile lesions of the thymus. Almost 50% of all mediastinal masses are located in the anterior mediastinum. The thymus is the most common site of origin of these masses. Several kinds of lesions can arise from this gland because it derives from the three embryonic germ cell layers. Primary neoplasms of the thymus are thymoma, thymolipomas, carcinoma, carcinoid, primary germ cell tumors, and lymphoma. The latter can also involve the organ in a secondary fashion. Other lesions that cause thymic enlargement and that can be confused with neoplasia are thymic cysts and thymic hyperplasia. Even though anterior mediastinal masses are first found on conventional radiographs, computed tomography and magnetic resonance are very useful additional studies for assessing the origin and extension of these masses. The basic concepts regarding embryology, anatomy, and histology relevant for the differential diagnosis of an enlarged thymic gland are also described.

Research paper thumbnail of Imaging Findings in Musculoskeletal Complications of AIDS

Radiographics, 2004

Patients with human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome... more 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.

Research paper thumbnail of Imaging Manifestations of Kaposi Sarcoma

Radiographics, 2006

Kaposi sarcoma (KS) is a low-grade vascular tumor that typically manifests as one of four variant... more 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.

Research paper thumbnail of Imaging Findings in Cardiac Tamponade with Emphasis on CT

Radiographics, 2007

Cardiac tamponade is a life-threatening condition that results from slow or rapid heart compressi... more 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.

Research paper thumbnail of Intramural hematoma of the esophagus: a pictorial essay

Emergency Radiology, 2008

Intramural hematoma of the esophagus (IHE) is a rare but well-documented condition that is part o... more 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 maybe treated conservatively with good outcome.

Research paper thumbnail of Appearance of the delta phalanx (longitudinally bracketed epiphysis) with MR imaging

Pediatric Radiology, 2011

The delta phalanx is an unusual condition occurring in the hand or the foot that can be distingui... more The delta phalanx is an unusual condition occurring in the hand or the foot that can be distinguished from a secondary ossification center on radiographic evaluation based on the well-defined phalangeal epiphyses typically evident by 24–30 months of age. MR imaging of the delta phalanx offers the advantage of visualizing sites of unossified bone before the age these findings are typically visible with radiography. We describe the case of a 15-month-old boy who presented with soft-tissue fusion of the third and fourth digits of the right hand. Radiograph and MR evaluation revealed soft-tissue intra-axial syndactyly of the third and fourth digits and a delta phalanx involving the proximal phalanx of the involved fourth digit.

Research paper thumbnail of CT and MR imaging findings of malignant cardiac tumors

Current Problems in Diagnostic Radiology, 2005

This article reviews CT and MRI features of malignant cardiac and pericardial tumors, most of whi... more 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.

Research paper thumbnail of Association of two respiratory congenital anomalies: tracheal diverticulum and cystic adenomatoid malformation of the lung

Pediatric Radiology, 2004

Many associations of congenital anomalies of the respiratory system have been reported, but the c... more Many associations of congenital anomalies of the respiratory system have been reported, but the combination of tracheal diverticulum and cystic adenomatoid malformation (CCAM) is unique. We present a patient with these two anomalies and analyze their embryological correlation.

Research paper thumbnail of CT and MR imaging findings of benign cardiac tumors

Current Problems in Diagnostic Radiology, 2005

This imaging review describes the appearance of benign cardiac tumors on CT and MRI. Although rar... more 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.

Research paper thumbnail of Imaging findings of expansile lesions of the thymus

Current Problems in Diagnostic Radiology, 2005

The purpose of this article is to review the imaging findings of the different expansile lesions ... more The purpose of this article is to review the imaging findings of the different expansile lesions of the thymus. Almost 50% of all mediastinal masses are located in the anterior mediastinum. The thymus is the most common site of origin of these masses. Several kinds of lesions can arise from this gland because it derives from the three embryonic germ cell layers. Primary neoplasms of the thymus are thymoma, thymolipomas, carcinoma, carcinoid, primary germ cell tumors, and lymphoma. The latter can also involve the organ in a secondary fashion. Other lesions that cause thymic enlargement and that can be confused with neoplasia are thymic cysts and thymic hyperplasia. Even though anterior mediastinal masses are first found on conventional radiographs, computed tomography and magnetic resonance are very useful additional studies for assessing the origin and extension of these masses. The basic concepts regarding embryology, anatomy, and histology relevant for the differential diagnosis of an enlarged thymic gland are also described.

Research paper thumbnail of Imaging Findings in Musculoskeletal Complications of AIDS

Radiographics, 2004

Patients with human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome... more 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.

Research paper thumbnail of Imaging Manifestations of Kaposi Sarcoma

Radiographics, 2006

Kaposi sarcoma (KS) is a low-grade vascular tumor that typically manifests as one of four variant... more 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.

Research paper thumbnail of Imaging Findings in Cardiac Tamponade with Emphasis on CT

Radiographics, 2007

Cardiac tamponade is a life-threatening condition that results from slow or rapid heart compressi... more 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.

Research paper thumbnail of Intramural hematoma of the esophagus: a pictorial essay

Emergency Radiology, 2008

Intramural hematoma of the esophagus (IHE) is a rare but well-documented condition that is part o... more 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 maybe treated conservatively with good outcome.

Research paper thumbnail of Imaging Appearances of the Sternum and Sternoclavicular Joints1

Radiographics, 2009

The sternum and sternoclavicular joints--critical structures of the anterior chest wall--may be a... more 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.

Research paper thumbnail of The Diaphragmatic Crura and Retrocrural Space: Normal Imaging Appearance, Variants, and Pathologic Conditions1

Radiographics, 2008

The retrocrural space (RCS) is a small triangular region within the most inferior posterior media... more 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.

Research paper thumbnail of Cardiovascular Complications of Human Immunodeficiency Virus Infection

Radiographics, 2006

The heart and great vessels are not the sites most frequently affected by opportunistic infection... more 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.

Research paper thumbnail of CT and MR imaging findings of malignant cardiac tumors

Current Problems in Diagnostic Radiology, 2005

This article reviews CT and MRI features of malignant cardiac and pericardial tumors, most of whi... more 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.

Research paper thumbnail of Association of two respiratory congenital anomalies: tracheal diverticulum and cystic adenomatoid malformation of the lung

Pediatric Radiology, 2004

Many associations of congenital anomalies of the respiratory system have been reported, but the c... more Many associations of congenital anomalies of the respiratory system have been reported, but the combination of tracheal diverticulum and cystic adenomatoid malformation (CCAM) is unique. We present a patient with these two anomalies and analyze their embryological correlation.

Research paper thumbnail of CT and MR imaging findings of benign cardiac tumors

Current Problems in Diagnostic Radiology, 2005

This imaging review describes the appearance of benign cardiac tumors on CT and MRI. Although rar... more 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.

Research paper thumbnail of Imaging findings of expansile lesions of the thymus

Current Problems in Diagnostic Radiology, 2005

The purpose of this article is to review the imaging findings of the different expansile lesions ... more The purpose of this article is to review the imaging findings of the different expansile lesions of the thymus. Almost 50% of all mediastinal masses are located in the anterior mediastinum. The thymus is the most common site of origin of these masses. Several kinds of lesions can arise from this gland because it derives from the three embryonic germ cell layers. Primary neoplasms of the thymus are thymoma, thymolipomas, carcinoma, carcinoid, primary germ cell tumors, and lymphoma. The latter can also involve the organ in a secondary fashion. Other lesions that cause thymic enlargement and that can be confused with neoplasia are thymic cysts and thymic hyperplasia. Even though anterior mediastinal masses are first found on conventional radiographs, computed tomography and magnetic resonance are very useful additional studies for assessing the origin and extension of these masses. The basic concepts regarding embryology, anatomy, and histology relevant for the differential diagnosis of an enlarged thymic gland are also described.

Research paper thumbnail of Imaging Findings in Musculoskeletal Complications of AIDS

Radiographics, 2004

Patients with human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome... more 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.

Research paper thumbnail of Imaging Manifestations of Kaposi Sarcoma

Radiographics, 2006

Kaposi sarcoma (KS) is a low-grade vascular tumor that typically manifests as one of four variant... more 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.

Research paper thumbnail of Imaging Findings in Cardiac Tamponade with Emphasis on CT

Radiographics, 2007

Cardiac tamponade is a life-threatening condition that results from slow or rapid heart compressi... more 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.

Research paper thumbnail of Intramural hematoma of the esophagus: a pictorial essay

Emergency Radiology, 2008

Intramural hematoma of the esophagus (IHE) is a rare but well-documented condition that is part o... more 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 maybe treated conservatively with good outcome.