Resumen:

Abstract

Purpose: Our purpose is to illustrate and describe typical and atypical imaging findings of supra- and infratentorial pilocytic astrocytoma (PA) on computed tomography (CT) and magnetic resonance imaging (MRI). Thirty-two patients with PA were selected from our case series. Twenty-four patients had confirmed PA from histologic analysis. The remaining 8 patients presented optic pathway gliomas and PA was the most relevant presumptive diagnosis. All patients, 20 male and 12 female (age range 10 months-65 years), underwent unenhanced and enhanced MRI. Diffusion-weighted imaging and MR spectroscopy (MRS) were performed in 6 patients, and 6 patients underwent CT scan.
The locations of the PA selected (n=32) were: optic pathway and hypothalamic-chiasmatic region (n=17) cerebellum (n=7), thalamus (n=6) and cerebral hemisphere (n=2).
On MRI, most PA appeared as solid-cystic masses, iso- to hypointense on T1-weighted images and hyperintense on T2-weighted images and FLAIR, with post-contrast enhancement.
Four patients presented atypical characteristics: 1 solid cerebellum PA with calcifications, 1 hypothalamus PA in a child without neurofibromatosis type 1(NF1) with no contrast enhancement and 1 cerebral hemisphere PA in a 65 year-old woman.
PAs are regarded as grade I tumors by the World Health Organization (WHO) classification. The optic pathway and the hypothalamic-chiasmatic region, as well as the posterior fossa are the most frequent locations. PAs are typically wellcircumscribed and solid-cystic lesions with low cellularity and slow growth.

Keywords. Pilocytic astrocytoma; glioma; magnetic resonance imaging.

Resumen:

El constante crecimiento del uso de radiaciones ionizantes en el Diagnóstico por Imágenes nos obliga a mantener una adecuada gestión de las dosis impartidas a los pacientes en cada estudio realizado. La dosimetría en radiología es un tema difícil de abordar, pero de vital importancia para una adecuada estimación de las dosis con las cuales estamos trabajando. La enorme concientización que, día a día, se percibe en nuestro país en estos temas es la respuesta adecuada a esta problemática. El presente artículo describe las principales unidades dosimétricas utilizadas y ejemplifica de manera sencilla, mediante valores de referencia conocidos internacionalmente, las dosis en radiología.

Palabras clave:
Dosimetría. Radioprotección.

Abstract
The steady growth in the use of ionizing radiation in diagnostic imaging requires a proper management of patients’ doses. Dosimetry in Radiology is a difficult topic to address, but it is vital to estimate the dose the patient receives. This article describes the main dosimetric units used and exemplifies doses in radiology in a simple manner through internationally known reference values.

Key Words:
Dosimetry; Radioprotection.

Resumen:

El hígado tiene una vascularización doble aportada por la arteria hepática y la vena porta. El uso de un protocolo de doble fase en los estudios de las lesiones focales del hígado se emplea principalmente para detectar y caracterizar tumores, en especial los hipervasculares. Sin embargo, es posible en ocasiones observar otros trastornos caracterizados por una refuerzo focal precoz que conducen a una alteración transitoria de la densidad. Entre las diferentes causas de los defectos transitorios de la perfusión hepática se incluyen la obstrucción del flujo venoso portal, alteraciones del flujo venoso hepático, cortocircuitos arterio-portales, malformaciones arteriovenosas, procesos inflamatorios, cirrosis y variantes anatómicas.

Palabras clave: Transitoria, hígado, perfusión, vascularización.

Abstract:
The liver has a dual blood supply provided by the hepatic artery and portal vein. The use of a dual-phase protocol studies of focal liver lesions are mainly used to detect and characterize tumor especially hypervascular. However, it sometimes possible to observe other dsorders characterized by early focal reinforcement leading to transient impairment density. Among the various causes of transient perfusion defects include hepatic portal vein obstruction hepatic venous flow abnormalities, arterio-portal shorts, arteriovenous malformations, inflammatory processes, cirrhosis and anatomic variants.
Key Words:
Transient, liver, perfusion, vascularization.

Resumen:

El avance delatecnología ha hecho quela Resonancia Magnética (RM) brinde unaexcelente herramienta paraeldiagnóstico, pronóstico y planeamiento terapéutico de muchas de las patologías que afectan al sistema cardiovascular. Expondremos resumidamente la técnica de la Resonancia Magnética Cardíaca (RMC), realizando una presentación iconográfica de los hallazgos imagenológicos en los estudios realizados en nuestro servicio. Existen dos secuencias básicas: la secuencia de “sangre negra” o spin echo, y la secuencia de “sangre blanca” o gradiente de echo (GE). La primera es utilizada para obtener información anatómica y la segunda principalmente para la valoración funcional cardíaca. La secuencia GE utilizada en la mayoría de los resonadores es la llamada Steady-State Free Precession (SSFP) o Secuencia de Estado Estacionario de Precesión Libre. La RMC ha revolucionado el estudio de las patologías cardiovasculares, obteniéndose imágenes de alta calidad.

Palabras clave:Resonancia magnética, patología cardíaca, enfermedad cardiovascular.

Abstract
Advances in technology have made MRI an excellent tool for the diagnosis, prognosis and therapeutic planning for many pathologies affecting the cardiovascular system. We will briefly discuss the technique of Cardiac MRI (or CMR) showing an iconographic presentation of image findings in studies performed in our department. There are two basic sequences, namely: sequence of "dark blood" or spin echo, and sequence of "bright blood" or gradient echo (GE). The first is used to obtain anatomical information and the second is mainly used for a functional cardiac evaluation. The GE sequence used in most resonators is called Steady-State Free Precession (SSFP). The study protocol is not based on the conventional orthogonal views but on views applied to the position of the heart in the thorax. CMR has revolutionized the study of cardiovascular diseases, obtaining high-quality images.

Key Words: Magnetic resonance, cardiopathy, cardiovascular disease.

Resumo:

Abstract

In the investigation of tumors with conventional magnetic resonance imaging, both quantitative characteristics, such as size, edema, necrosis, and presence of metastases, and qualitative characteristics, such as contrast enhancement degree, are taken into consideration. However, changes in cell metabolism and tissue physiology which precede morphological changes cannot be detected by the conventional technique. The development of new magnetic resonance imaging techniques has enabled the functional assessment of the structures in order to obtain information on the different physiological processes of the tumor microenvironment, such as oxygenation levels, cellularity and vascularity. The detailed morphological study in association with the new functional imaging techniques allows for an appropriate approach to cancer patients, including the phases of diagnosis, staging, response evaluation and follow-up, with a positive impact on their quality of life and survival rate.

Keywords: Cancer imaging; Magnetic resonance imaging; Oncology; Neoplasia; Functional imaging; Diffusion.

Resumo:

To correlate the results of 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) performed with a specific protocol for assessment of breasts with histological/immunohistochemical findings in breast carcinoma patients.
Materials and Methods:
Cross-sectional study with prospective data collection, where patients with biopsy-confirmed breast carcinomas were studied. The patients underwent PET/CT examination in prone position, with a specific protocol for assessment of breasts. PET/CT findings were compared with histological and immunohistochemical data.
Results:
The authors identified 59 malignant breast lesions in 50 patients. The maximum diameter of the lesions ranged from 6 to 80 mm (mean: 32.2 mm). Invasive ductal carcinoma was the most common histological type (n = 47; 79.7%). At PET/CT, 53 (89.8%) of the lesions demonstrated anomalous concentrations of 18F-FDG, with maximum SUV ranging from 0.8 to 23.1 (mean: 5.5). A statistically significant association was observed between higher values of maximum SUV and histological type, histological grade, molecular subtype, tumor diameter, mitotic index and Ki-67 expression.
Conclusion:
PET/CT performed with specific protocol for assessment of breasts has demonstrated good sensitivity and was associated with relevant histological/immunohistochemical factors related to aggressiveness and prognosis of breast carcinomas.

Resumen:

Abstract:
Giant condyloma acuminata (Buschke - Lowenstein tumor) is a rare disease that commonly affects immunocompromised patients, presenting a high percentage of malignancy, recurrence rate and mortality. There is little agreement regarding treatment and post-operative controls, where imaging studies play an important role, existing literature regarding this is limited. In this review, we present the cases of seven patients, along with their characteristics mainly on MRI as well as CT scan, in addition to a revision of the literature. In most cases, pedunculated exophytic “caulifower-like” lesions are observed. In CT they present soft-tissue density and vascularization. In magnetic resonance imaging they are isointense on T1, slightly hyperintense on T2, with restricted diffusion on DWI, and heterogenous enhancement on gadolinium administration, maintaining their enhancement in later stages.

Key Words:
Buschke-Lowenstein tumor, Giant condyloma acuminata, Magnetic resonance imaging

Resumen:

Abstract:

Urinary diversion surgeries are procedures that are becoming more frequent, as their indications are not only neoplastic, being useful also in managing other diseases. Due to this increase, it is not uncommon to observe secondary complications, whether in the early postoperative period (less than 30 days after surgery) or later (more than 30 days). Within these are alterations in intestinal motility (paralytic ileus, blockage), anastomotic leaks, fluid collections (lymphocele, urinoma, abscess), fistulas, parastomal herniation, ureteral obstruction, urolithiasis and tumor recurrence. Given the large number of surgical techniques used in these procedures, it is important to know the resulting anatomical changes, occasionally difficult to evaluate. Multidetector computed tomography (MDCT) is of great use in the study of these patients, especially with multiplanar reconstruction techniques, adequately representing the affected urinary and extra-urinary structures, and their relationship to adjacent structures, enabling their accurate and quick identification
Key Words:
Cystectomy, Multidetector computed tomography, Postoperative complications, Urinary diversion.

Resumen:

Summary

Objective:
To evaluate the available data of Breast tomosynthesis as a complementary tool of direct digital mammography.
Methods:
A systematic literature search of original and review articles through pubmed was performed. we reviewed the most important aspects of tomosynthesis in breast imaging
Results:
36 original articles, 13 review articles and the fda and american College of radiology standards were included. Breast tomosynthesis has showed a positive impact in breast cancer screening, improving the rate of cancer detection due to visualization of small lesions unseen in 2d (such as distortion of the architecture) and it has greater precision regarding tumor size. In addition, it improves the specificity of mammographic evaluation, decreasing the recall rate. limitations: interpretation time, cost and low sensitivity to calcifications.
Conclusions:
Breast tomosynthesis is a new complementary tool of digital mammography which has showed a positive impact in breast cancer diagnosis in comparison to the conventional 2d mammography. decreased recall rates could have significant impact in costs, early detection and a decrease in anxiety.

Key words: Mammography. Tomography. Diagnosis. Breast neoplasms

Resumen:

Abstract

Objective: The therapeutic approach of adenomas has changed in recent years, especially because of the possibilities for characterization by means of diagnostic imaging methods, mainly magnetic resonance imaging, which allowed us, in most cases, to approach the type of adenoma.
Methods: A review of the recent literature was conducted in order to describe the characteristic imaging features of the types of adenomas in the different imaging techniques, with an emphasis on MRI, which allows differentiation between histologic subtypes of adenomas. In addition, it also helps guide medical or surgical management.
Results: In the literature, we described hepatic adenomatosis as an entity which is frequently found in women, with atypical imaging features. In addition, we mentioned the characteristics of MRI findings and their correlation with the types of adenomas, inflammatory, steatosic, β-catenin mutated and mixed.
Conclusion: According to the classification based on genetic, histopathological and imaging features of the different subtypes of AHC, we could determine the natural history, define prognosis and the therapeutic options or imaging follow-up.

Key words: Hepatocellular adenoma, Magnetic resonance Imaging, Adenoma, Liver cell

Resumen:

Abstract:
Perfusion MRI makes it possible to evaluate the cerebral microvasculature through changes in signal due to a tracer passing through blood vessels. The most commonly used technique is based on the magnetic susceptibility of gadolinium in T2*-weighted sequences, and the most commonly evaluated parameters are cerebral blood volume, cerebral blood flow, and mean transit time. Diverse technical aspects, like the sequence used, and the dose and speed of contrast material injection, must be taken into account in perfusion MRI studies. It is also essential to consider possible sources of error like contrast material leaks due to changes in the permeability of the blood---brain barrier. The most widely used clinical applications of perfusion MRI include the determination of the degree of aggressiveness of gliomas, the differentiation of some histological types of tumors or pseudotumors, and the evaluation of the penumbral area in acute ischemia.

Keywords: Perfusion magnetic resonance imaging. Brain tumors. Multiple sclerosis. Cerebral thrombosis.

Resumen:

Abstract:

Acute pain in the right iliac fossa (RIF) is common in children. It can arise from a wide variety of gastrointestinal and genitourinary processes that make up the differential diagnosis with acute appendicitis (AA). In this article, we describe the most representative findings of these processes on ultrasonography (US). We emphasize the characteristics that enable these processes to be differentiated from AA.

Key Words:Abdominal ultrasonography. Right iliac fossa. Pediatrics. Acute abdomen. Appendicitis. Crohn’s disease.

Resumen:

Abstract:
Perfusion MRI makes it possible to evaluate the cerebral microvasculature through changes in signal due to a tracer passing through blood vessels. The most commonly used technique is based on the magnetic susceptibility of gadolinium in T2*-weighted sequences, and the most commonly evaluated parameters are cerebral blood volume, cerebral blood flow, and mean transit time. Diverse technical aspects, like the sequence used, and the dose and speed of contrast material injection, must be taken into account in perfusion MRI studies. It is also essential to consider possible sources of error like contrast material leaks due to changes in the permeability of the blood---brain barrier. The most widely used clinical applications of perfusion MRI include the determination of the degree of aggressiveness of gliomas, the differentiation of some histological types of tumors or pseudotumors, and the evaluation of the penumbral area in acute ischemia.
Objectives: To perform a retrospective study of bone and soft tissue percutaneous biopsy punctures (PBP) in order to evaluate the diagnostic accuracy of the sample adequacy and safety of the procedure. Outline the role of the physician in PBP interventional imaging.
Material and Methods: this is a retrospective, descriptive study witch analyzes 284 consecutive bone and soft tissue percutaneous biopsy punctures under tomographic guidance; it was performed by a single operator from April 2006 to September 2013, in seven institutions of our country. The samples were analyzed by the pathologist designated by the institution. The charts were reviewed for patient outcomes to assess the diagnostic accuracy.
Results: The diagnostic accuracy was 91.7%, specificity of 96% and 4% false negatives. There were no major complications. Conclusions: Percutaneous needle biopsy , bone and soft tissue CT-guided technique is reliable and safe to perform diagnostic high degree of accuracy. The trained Interventional Medical Imaging operator can perform these procedures successfully and with few or no complications.

Keywords: percutaneus biopsy puncture, bone biopsy, soft tissue biopsy, computed tomography, diagnostic performance.

Resumen:

Abstract:

With the introduction of molecularly targeted chemotherapeutics, there is an increasing need for defining new response criteria for therapeutic success because use of morphologic imaging alone may not fully assess tumor response. Computed tomographic (CT) perfusion imaging of the liver provides functional information about the microcirculation of normal parenchyma and focal liver lesions and is a promising technique for assessing the efficacy of various anticancer treatments. CT perfusion also shows promising results for diagnosing primary or metastatic tumors, for predicting early response to anticancer treatments, and for monitoring tumor recurrence after therapy. Many of the limitations of early CT perfusion studies performed in the liver, such as limited coverage, motion artifacts, and high radiation dose of CT, are being addressed by recent technical advances. These include a wide area detector with or without volumetric spiral or shuttle modes, motion correction algorithms, and new CT reconstruction technologies such as iterative algorithms. Although several issues related to perfusion imaging such as paucity of large multicenter trials, limited accessibility of perfusion software, and lack of standardization in methods—remain unsolved, CT perfusion has now reached technical maturity, allowing for its use in assessing tumor vascularity in larger-scale prospective clinical trials. In this review, basic principles, current acquisition protocols, and pharmacokinetic models used for CT perfusion imaging of the liver are described. Various oncologic applications of CT perfusion of the liver are discussed and current challenges, as well as possible solutions, for CT perfusion are presented.

Abstract:

Abstract:

Actinomycosis is a chronic suppurative bacterial infection caused by Actinomyces species. Actinomyces israelii is the organism most commonly found in human disease. Actinomycosis usually manifests with abscess formation, dense fibrosis, and draining sinuses. The disease is further characterized by the tendency to extensively spread beyond normal fascial and connective tissue planes. Actinomycosis occurs most commonly in the cervicofacial region (50%–65%), followed by the thoracic (15%–30%) and abdominopelvic (20%) regions, but rarely involves the central nervous system. Most cases of cervicofacial actinomycosis are odontogenic in origin. In the acute form, cervicofacial disease can manifest with soft-tissue swelling, a painful pyogenic abscess, or a mass lesion. In the subacute to chronic form, a painless indurated mass can spread to the skin, leading to draining sinus tracts. Thoracic manifestations include parenchymal, bronchiectatic, and endobronchial actinomycosis. At computed tomography, pulmonary actinomycosis usually appears as chronic segmental airspace consolidation containing necrotic low-attenuation areas with peripheral enhancement. Abdominopelvic actinomycosis preferentially involves the ileocecal region, ovary, and fallopian tube. The imaging findings favoring abdominopelvic actinomycosis include strong enhancement in the solid portion of the mass after contrast material administration, small rim-enhancing abscesses within the mass, and extensive inflammatory extensions. Actinomycosis in the central nervous system may produce brain abscess, meningitis, subdural empyema, actinomycetoma, and spinal and cranial epidural abscess. In general, actinomycosis responds well to antibiotic therapy, but long-term follow-up after treatment is needed because of frequent relapses.