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Featured researches published by Daniel Ocazionez.


Radiographics | 2011

Aortitis: imaging spectrum of the infectious and inflammatory conditions of the aorta.

Carlos S. Restrepo; Daniel Ocazionez; Rajeev Suri; Daniel Vargas

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.


Emergency Radiology | 2007

Intramural hematoma of the esophagus: a pictorial essay

Carlos S. Restrepo; Diego F. Lemos; Daniel Ocazionez; Rogelio Moncada; Carlos R Giménez

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.


Radiographics | 2008

The Diaphragmatic Crura and Retrocrural Space: Normal Imaging Appearance, Variants, and Pathologic Conditions

Carlos S. Restrepo; Andrés Eraso; Daniel Ocazionez; Julio A. Lemos; Santiago Martinez; Diego F. Lemos

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.


Radiographics | 2012

Imaging Patients with Cardiac Trauma

Carlos S. Restrepo; Fernando R. Gutierrez; Juan Marmol-Velez; Daniel Ocazionez; Santiago Martinez-Jimenez

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.


Radiographics | 2013

Primary Pericardial Tumors

Carlos S. Restrepo; Daniel Vargas; Daniel Ocazionez; Santiago Martinez-Jimenez; Sonia L. Betancourt Cuellar; Fernando R. Gutierrez

Primary pericardial tumors are rare and may be classified as benign or malignant. The most common benign lesions are pericardial cysts and lipomas. Mesothelioma is the most common primary malignant pericardial neoplasm. Other malignant tumors include a wide variety of sarcomas, lymphoma, and primitive neuroectodermal tumor. When present, signs and symptoms are generally nonspecific. Patients often present with dyspnea, chest pain, palpitations, fever, or weight loss. Although the imaging approach usually begins with plain radiography of the chest or transthoracic echocardiography, the value of these imaging modalities is limited. Cross-sectional imaging, on the other hand, plays a key role in the evaluation of these lesions. Computed tomography and magnetic resonance imaging allow further characterization and may, in some cases, provide diagnostic findings. Furthermore, the importance of cross-sectional imaging lies in assessing the exact location of the tumor in relation to neighboring structures. Both benign and malignant tumors may result in compression of vital mediastinal structures. Malignant lesions may also directly invade structures, such as the myocardium and great vessels, and result in metastatic disease. Imaging plays an important role in the detection, characterization, and staging of pericardial tumors; in their treatment planning; and in the posttreatment follow-up of affected patients. The prognosis of patients with benign tumors is good, even in the few cases in which surgical intervention is required. On the other hand, the length of survival for patients with malignant pericardial tumors is, in the majority of cases, dismal.


Seminars in Ultrasound Ct and Mri | 2011

Kaposi's sarcoma: Imaging overview

Carlos S. Restrepo; Daniel Ocazionez

Kaposis 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.


Radiographics | 2017

Pulmonary Tuberculosis: Role of Radiology in Diagnosis and Management.

Arun C. Nachiappan; Kasra Rahbar; Xiao Shi; Elizabeth Guy; Eduardo J. Mortani Barbosa; Girish S. Shroff; Daniel Ocazionez; Alan E Schlesinger; Sharyn I. Katz; Mark M. Hammer

Tuberculosis is a public health problem worldwide, including in the United States-particularly among immunocompromised patients and other high-risk groups. Tuberculosis manifests in active and latent forms. Active disease can occur as primary tuberculosis, developing shortly after infection, or postprimary tuberculosis, developing after a long period of latent infection. Primary tuberculosis occurs most commonly in children and immunocompromised patients, who present with lymphadenopathy, pulmonary consolidation, and pleural effusion. Postprimary tuberculosis may manifest with cavities, consolidations, and centrilobular nodules. Miliary tuberculosis refers to hematogenously disseminated disease that is more commonly seen in immunocompromised patients, who present with miliary lung nodules and multiorgan involvement. The principal means of testing for active tuberculosis is sputum analysis, including smear, culture, and nucleic acid amplification testing. Imaging findings, particularly the presence of cavitation, can affect treatment decisions, such as the duration of therapy. Latent tuberculosis is an asymptomatic infection that can lead to postprimary tuberculosis in the future. Patients who are suspected of having latent tuberculosis may undergo targeted testing with a tuberculin skin test or interferon-γ release assay. Chest radiographs are used to stratify for risk and to assess for asymptomatic active disease. Sequelae of previous tuberculosis that is now inactive manifest characteristically as fibronodular opacities in the apical and upper lung zones. Stability of radiographic findings for 6 months distinguishes inactive from active disease. Nontuberculous mycobacterial disease can sometimes mimic the findings of active tuberculosis, and laboratory confirmation is required to make the distinction. Familiarity with the imaging, clinical, and laboratory features of tuberculosis is important for diagnosis and management. ©RSNA, 2017.


Radiographics | 2016

Hypertrophic Cardiomyopathy from A to Z: Genetics, Pathophysiology, Imaging, and Management

Ameya Jagdish Baxi; Carlos S. Restrepo; Daniel Vargas; Alejandro Marmol-Velez; Daniel Ocazionez; Horacio Murillo

Hypertrophic cardiomyopathy (HCM) is a heterogeneous group of diseases related to sarcomere gene mutations exhibiting heterogeneous phenotypes with an autosomal dominant mendelian pattern of inheritance. The disorder is characterized by diverse phenotypic expressions and variable natural progression, which may range from dyspnea and/or syncope to sudden cardiac death. It is found across all racial groups and is associated with left ventricular hypertrophy in the absence of another systemic or cardiac disease. The management of HCM is based on a thorough understanding of the underlying morphology, pathophysiology, and clinical course. Imaging findings of HCM mirror the variable expressivity and penetrance heterogeneity, with the added advantage of diagnosis even in cases where a specific mutation may not yet be found. The diagnostic information obtained from imaging varies depending on the specific stage of HCM-phenotype manifestation, including the prehypertrophic, hypertrophic, and later stages of adverse remodeling into the burned-out phase of overt heart failure. However, subtle or obvious, these imaging findings become critical components in diagnosis, management, and follow-up of HCM patients. Although diagnosis of HCM traditionally relies on clinical assessment and transthoracic echocardiography, recent studies have demonstrated increased utility of multidetector computed tomography (CT) and particularly cardiac magnetic resonance (MR) imaging in diagnosis, phenotype differentiation, therapeutic planning, and prognostication. In this article, we provide an overview of the genetics, pathophysiology, and clinical manifestations of HCM, with the spectrum of imaging findings at MR imaging and CT and their contribution in diagnosis, risk stratification, and therapy.


Journal of Thoracic Imaging | 2014

Magnetic resonance imaging safety in cardiothoracic imaging

Daniel Ocazionez; Demetrius L. Dicks; Jennifer L. Favinger; Girish S. Shroff; Sidhdharth Damani; Gregory Kicska; Gautham P. Reddy

Patient safety is a priority for patients undergoing magnetic resonance imaging (MRI). This article reviews MRI safety issues related to devices, pharmacologic stress agents, contrast agents, anesthesia, and external equipment, focusing on cardiothoracic MRI.


Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery | 2017

Traditional Sternotomy Versus Minimally Invasive Aortic Valve Replacement in Patients Stratified by Ejection Fraction

Tom C. Nguyen; Vinod H. Thourani; Justin Q. Pham; Yelin Zhao; Matthew D. Terwelp; Prakash Balan; Daniel Ocazionez; Catalin Loghin; Richard W. Smalling; Anthony L. Estrera; Joseph Lamelas

Objective Low ejection fraction (EF < 40%) portends adverse outcomes in patients undergoing valvular heart surgery. The role of traditional median sternotomy aortic valve replacement (SAVR) compared with minimally invasive aortic valve replacement (MIAVR) in this cohort remains incompletely understood. Methods A multi-institutional retrospective review of 1503 patients who underwent SAVR (n = 815) and MIAVR via right anterior thoracotomy (n = 688) from 2011 to 2014 was performed. Patients were stratified into two groups: EF of less than 40% and EF of 40% or more. In each EF group, SAVR and MIAVR patients were propensity matched by age, sex, body mass index, race, diabetes, hypertension, dyslipidemia, dialysis, cerebrovascular disease, cardiovascular disease, cerebro-vascular accident, peripheral vascular disease, last creatinine level, EF, previous MI and cardiogenic shock, and the Society for Thoracic Surgeons (STS) score. Results Among patients with an EF of 40% or more (377 pairs), patients who underwent MIAVR compared with SAVR had decreased intensive care unit hours (56.8% vs 84.6%, P < 0.001), postoperative length of stay (7.1 vs 7.9 days, P = 0.04), incidence of atrial fibrillation (18.8% vs 38.7%, P < 0.001), bleeding (0.8% vs 3.2%, P = 0.04), and a trend toward decreased 30-day mortality (0.3% vs 1.3%, P = 0.22). The STS scores were largely equivalent in patients undergoing MIAVR compared with SAVR (2.4% vs 2.6%, P = 0.09). In patients with an EF of less than 40% (35 pairs), there was no difference in intensive care unit hours (69% vs 72.6%, P = 0.80), postoperative length of stay (10.3 vs 7.2 days, P = 0.13), 30-day mortality (3.8% vs 0.8%, P = 0.50), or the STS score (3.3% vs 3.2%, P = 0.68). Conclusions Minimally invasive aortic valve replacement in patients with preserved EF was associated with improved short-term outcomes compared with SAVR. In patients with left ventricular dysfunction, short-term outcomes between MIAVR and SAVR are largely equivalent.

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Carlos S. Restrepo

University of Texas Health Science Center at San Antonio

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Daniel Vargas

University of Colorado Denver

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Girish S. Shroff

University of Texas MD Anderson Cancer Center

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Anthony L. Estrera

University of Texas Health Science Center at Houston

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Ameya Jagdish Baxi

University of Texas Health Science Center at San Antonio

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Hazim J. Safi

University of Texas Health Science Center at Houston

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Prakash Balan

University of Texas at Austin

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