Eugenio Zalaquett

Chronic venous insufficiency is a common condition caused by valvular incompetence and/or obstruction of the lower extremity venous system. Chronic venous insufficiency presents in a wide range of clinical presentations, ranging from mild pain or edema to the development of varicose veins and nonhealing venous ulcers. Doppler ultrasound is the preferred imaging modality in the assessment of this condition and provides both anatomical and functional information in a noninvasive, cost-effective… Show more

Chronic venous insufficiency is a common condition caused by valvular incompetence and/or obstruction of the lower extremity venous system. Chronic venous insufficiency presents in a wide range of clinical presentations, ranging from mild pain or edema to the development of varicose veins and nonhealing venous ulcers. Doppler ultrasound is the preferred imaging modality in the assessment of this condition and provides both anatomical and functional information in a noninvasive, cost-effective, and radiation-free manner. Knowledge of the anatomy and nomenclature, pathophysiology, equipment requisites, scanning protocols, relevant findings, and reporting nuances is essential to the creation of an accurate and clinically actionable report. Evaluation of the superficial and deep venous system for degree and extent of reflux is necessary to establish the diagnosis and to institute appropriate treatment. Show less

Prostate cancer is the second most common malignancy among men worldwide. The usual diagnostic pathway used to select at-risk patients for clinically significant prostate cancer was digital examination and measurement of prostate specific antigen (PSA) in blood, but this approach is associated with a high number of false-positives and thus unnecessary transrectal biopsies, raising costs and morbidity. Multiparametric MRI (mpMRI) was developed as a method to better select at-risk patients using… Show more

Prostate cancer is the second most common malignancy among men worldwide. The usual diagnostic pathway used to select at-risk patients for clinically significant prostate cancer was digital examination and measurement of prostate specific antigen (PSA) in blood, but this approach is associated with a high number of false-positives and thus unnecessary transrectal biopsies, raising costs and morbidity. Multiparametric MRI (mpMRI) was developed as a method to better select at-risk patients using medical imaging. Prostate Imaging Reporting and Data System (PI-RADS) was established as a methodology to standardize and enhance the use of mpMRI, as it has been done before with other organs such as breasts and thyroid. Nevertheless, there are several imaging findings that can mimic prostate cancer in mpMRI. Normal anatomy, non-neoplastic pathology, post treatment changes and technical issues can generate imaging findings on both morphological and functional sequences that overlap with prostate cancer on both the transition and the peripheral zones. Knowledge of these potential pitfalls by mpMRI readers is crucial to recognize them and to offer better quality of care for patients. Show less

The arrival of the COVID-19 pandemic originated by the SARS-CoV-2 virus has required a quick response by multiple medical specialties, including Imaging. Lung Ultrasound is an exam that has previously demonstrated its utility in other lung diseases, with high availability, low cost, absence of ionizing radiation and the possibility to have a bed-side assessment. In some of the countries that experienced earlier and more intense effects of the pandemic, as China and Italy, it has been used as an… Show more

The arrival of the COVID-19 pandemic originated by the SARS-CoV-2 virus has required a quick response by multiple medical specialties, including Imaging. Lung Ultrasound is an exam that has previously demonstrated its utility in other lung diseases, with high availability, low cost, absence of ionizing radiation and the possibility to have a bed-side assessment. In some of the countries that experienced earlier and more intense effects of the pandemic, as China and Italy, it has been used as an imaging modality for evaluation and follow-up for COVID-19 patients. In order to achieve a satisfactory result, adequate equipment, protection, disinfection and protocol must be chosen. The US findings described so far in the literature are nonspecific, but their combination and anatomical distribution in a compatible clinical and epidemiologic context, made them highly suggestive of this disease and allow for a serial follow-up. The current literature is scarce and more evidence is needed to truly estimate the usefulness of this imaging modality in the evaluation of COVID-19 patients. Show less

To describe the involvement diagnostic imaging exams in the framework of Regime of Explicit Health Guarantees in Chile and analyze the role of radiologists in this field. Materials and methods: Every pathology included in the Explicit Healthcare Guarantees Program encompasses an expert consensus clinical guideline (CG) and a specific services list (SL). Both of them were analyzed regarding the amount and modality of imaging exams recommended, the presence of radiologists within the expert… Show more

To describe the involvement diagnostic imaging exams in the framework of Regime of Explicit Health Guarantees in Chile and analyze the role of radiologists in this field. Materials and methods: Every pathology included in the Explicit Healthcare Guarantees Program encompasses an expert consensus clinical guideline (CG) and a specific services list (SL). Both of them were analyzed regarding the amount and modality of imaging exams recommended, the presence of radiologists within the expert panels and the concordance between guidelines recommendations and service lists. Results: 60 CG (67%) and 55 SL (69%) include imaging tests within their guaranteed services. Seven CG (8%) recommend medical imaging tests not covered in their respective services list and 5 SL (6%) reference imaging tests not included in the clinical guidelines. The involvement of a radiologist on the expert panel was associated with the absence of imaging test discrepancies between CG and SL (p=0.007). Discussion: Diagnostic imaging plays an important role within the Explicit Healthcare Guarantees Program and is associated with rising healthcare costs. There are cases of discordance between clinical guidelines and specific services lists that account for significant economic and social costs, which may be reduced by including radiologists on expert panels, optimizing resource use and lowering patients’ exposure to ionizing radiation. Show less

Hydatid disease (HD) is a parasitic infection caused by the larvae of a tapeworm that is endemic to many regions around the world—South America, Africa, and Asia, in particular. Humans are infected as intermediate hosts in the parasite’s life cycle; thus, HD can be seen in persons living in areas where animal husbandry is practiced. However, owing to the varied patterns of migration and immigration during the past several decades, HD can be diagnosed in individuals living anywhere. The liver is… Show more

Hydatid disease (HD) is a parasitic infection caused by the larvae of a tapeworm that is endemic to many regions around the world—South America, Africa, and Asia, in particular. Humans are infected as intermediate hosts in the parasite’s life cycle; thus, HD can be seen in persons living in areas where animal husbandry is practiced. However, owing to the varied patterns of migration and immigration during the past several decades, HD can be diagnosed in individuals living anywhere. The liver is the most common organ involved, with hepatic HD accounting for the majority of published cases. However, HD can affect multiple organs and tissues other than the liver, including the spleen, kidneys, lungs, heart, peritoneum, muscles, and brain. Knowledge of the route of spread, clinical findings at presentation, and possible complications involving each extrahepatic location can be useful for the radiologist when evaluating imaging findings in patients suspected of having HD. The ultrasonographic, computed tomographic, and magnetic resonance imaging findings of extrahepatic hydatid lesions frequently simulate those of hepatic HD, as long as rupture, bleeding, and/or superimposed bacterial infection has not occurred. Specific features of HD seen at different extrahepatic sites can help tailor the diagnosis. The differential diagnoses that can mimic HD at every nonhepatic location should be considered, as many of these entities are common, especially in nonendemic areas. Show less

RadioGraphics continues to publish radiologic-pathologic case material selected from the American Institute for Radiologic Pathology (AIRP) “best case” presentations. The AIRP conducts a 4-week Radiologic Pathology Correlation Course, which is offered five times per year. On the penultimate day of the course, the best case presentation is held at the American Film Institute Silver Theater and Cultural Center in Silver Spring, Md. The AIRP faculty identifies the best cases, from each organ… Show more

RadioGraphics continues to publish radiologic-pathologic case material selected from the American Institute for Radiologic Pathology (AIRP) “best case” presentations. The AIRP conducts a 4-week Radiologic Pathology Correlation Course, which is offered five times per year. On the penultimate day of the course, the best case presentation is held at the American Film Institute Silver Theater and Cultural Center in Silver Spring, Md. The AIRP faculty identifies the best cases, from each organ system, brought by the resident attendees. One or more of the best cases from each of the five courses are then solicited for publication in RadioGraphics. These cases emphasize the importance of radiologic-pathologic correlation in the imaging evaluation and diagnosis of diseases encountered at the institute and its predecessor, the Armed Forces Institute of Pathology (AFIP). Show less

Imaging plays an important role in the diagnosis, characterization, and management of infectious liver disease. In clinical practice, the main contributions of imaging are in detecting early disease, excluding other entities with a similar presentation, establishing a definitive diagnosis when classic findings are present, and guiding appropriate antimicrobial, interventional, or surgical treatment. The most common imaging features of bacterial, viral, parasitic, and fungal hepatic infections… Show more

Imaging plays an important role in the diagnosis, characterization, and management of infectious liver disease. In clinical practice, the main contributions of imaging are in detecting early disease, excluding other entities with a similar presentation, establishing a definitive diagnosis when classic findings are present, and guiding appropriate antimicrobial, interventional, or surgical treatment. The most common imaging features of bacterial, viral, parasitic, and fungal hepatic infections are described, and key imaging and clinical manifestations are reviewed that may be useful to narrow the differential diagnosis and avoid pitfalls in image interpretation. Ultrasonography (US), computed tomography (CT), and magnetic resonance imaging allow accurate detection of most hepatic infections and, in some circumstances, may provide specific signs to identify the underlying pathogen and exclude other entities with similar imaging features. In bacterial and parasitic infections, specific imaging features may be enough to exclude a neoplasm and, occasionally, to identify the underlying infectious agent. US and CT are important means to guide percutaneous aspiration or drainage when needed. In viral infections, imaging is critical to exclude entities that may manifest with similar clinical and laboratory findings. Disseminated fungal infections require early detection at imaging because they can be fatal if not promptly treated. Familiarity with the epidemiology, pathogenesis, clinical manifestations, imaging features, and treatment of hepatic infections can aid in radiologic diagnosis and guide appropriate patient care. Show less

Osteoarthritis is the more frequent cause of disability in adult people and it is associated to cartilage degeneration of affected joints. This cartilage has a limited ability to repair. Several treatments have been tested including the use of Mesenchymal Stem Cells. These cells are an attractive source for cartilage repair because of their availability to chodrogenic differentiation by progressing sequentially through the expression of cartilage specific extracelullar matrix molecules, as in… Show more

Osteoarthritis is the more frequent cause of disability in adult people and it is associated to cartilage degeneration of affected joints. This cartilage has a limited ability to repair. Several treatments have been tested including the use of Mesenchymal Stem Cells. These cells are an attractive source for cartilage repair because of their availability to chodrogenic differentiation by progressing sequentially through the expression of cartilage specific extracelullar matrix molecules, as in the embryologic human development. The aim is to obtain, culture and differentiate rabbit Bone Marrow derived Mesenchymal Stem Cells in vitro to chondral lineage. By differential centrifugation the mononuclear cell level was obtained from rabbit bone marrow samples. This level was cultured until 70% confluence. Chondrogenic differentiation was performed in an aggregate culture system with TGF-b1. Sample quantity, culture efficiency, confluence time of cultures and differentiation quality were all evaluated. An average sample of 14.5 ml per side was obtained, culture efficiency was 80%, and average confluence time (70%) was 18 days. Differentiation culture had an 80% efficiency and optimal differentiation quality. Rabbit Bone Marrow derived Mesenchymal Stem Cells culture is a reproducible technique and by the use of an adequate methodology chondrogenic cells can be obtained in vitro. This model permits the study of chondral differentiation process and could have direct clinical application. This is the first successful Latin-American report in Mesenchymal Stem Cells culture and chondrogenic differentiation. Show less