Objetivo:

Rationale and Objectives:
To evaluate the diagnostic accuracy of multidetector computed tomography (MDCT) for the detection of luminal stenosis and cardiac allograft vasculopathy in comparison with coronary angiography (CA) and intravascular ultrasound (IVUS), respectively.

Materials and Methods:
Nineteen cardiac transplant patients undergoing follow-up CA were included. MDCT coronary angiography was performed using a 16-row CT scanner within 7-14 days after CA and IVUS. Studies were analyzed by independent readers, who evaluated the CT studies for the presence of coronary artery stenosis >50% and allograft vasculopathy.

Results:
Regarding the detection of luminal stenosis >50%, sensitivity was 80-88% and specificity 98-99%. Regarding the detection of cardiac allograft vasculopathy, sensitivity was 91-96% and specificity 88-91%.

Conclusion:
In this preliminary series, our results showed that MDCT coronary angiography was a suitable technique for the evaluation of heart transplant patients and could be an alternative to CA and IVUS in the follow-up and noninvasive contr ol of these patients.

Key Words: Allograft vasculopathy. Transplantation. Multidetector computed tomography. Intravascular ultrasound.

Objetivo:
Mostrar las diversas variantes anatómicas vasculares tanto arteriales como venosas en el estudio angiográfico renal por tomografía computada multidetector (TCMD) de 64 canales, dada su implicancia en un eventual planeamiento quirúrgico.

Material y métodos:
Se evaluaron retrospectivamente 26 estudios realizados con tomógrafo Philips Brillance de 64 canales. Se obtuvieron secuencias sin contraste y postcontraste e.v. en fases arterial y venosa, administrado con bomba inyectora doble cabezal. Para una fase arterial apropiada se utilizó técnica de bolus track. Las imágenes fueron posteriormente procesadas en Workstation Philips Brillance 190P en un tiempo promedio de 30 minutos y reconstruidas con técnicas MIP y volumétrica

Resultados:
Dentro de las variantes anatómicas arteriales, se encontraron: bifurcaciones prehiliares (n=3), arterias accesorias (n=4) y arterias polares (n=9). Dentro de las variantes venosas fueron halladas: venas renales múltiples (n=5), venas circumaórticas (n=2), retroaórticas (n=2) y vena tributaria lumbar prominente (n=1). Conclusión: El estudio vascular renal adquiere importancia en el planeamiento quirúrgico en casos de nefrectomías parciales, laparoscópicas y en el transplante renal. Esto otorga suma utilidad al estudio de TCMD de 64 canales, tanto por su eficacia diagnóstica, ya que por la alta calidad de las reconstrucciones obtenidas llega a igualar a la angiografía digital, como por tratarse de un método no invasivo.

Conclusión: El estudio vascular renal adquiere importancia en el planeamiento quirúrgico en casos de nefrectomías parciales, laparoscópicas y en el transplante renal. Esto otorga suma utilidad al estudio de TCMD de 64 canales, tanto por su eficacia diagnóstica, ya que por la alta calidad de las reconstrucciones obtenidas llega a igualar a la angiografía digital, como por tratarse de un método no invasivo.

Palabras clave: AngioTC. TC multidetector. Angiografía renal por TC.

Rationale and Objectives:
To show the wide range of anatomic vascular variants (both arterial and venous), which can be seen in the renal angiography using the 64-multidetector row computed tomography (64-MDCT), given their importance in a potential surgical planning

Materials and Methods:
A total of 26 studies performed with a 64-channel Philips Brillance CT scanner were retrospectively analyzed. Non-enhanced and enhanced (arterial and venous) phases were obtained. For contrast material injection, a double head injector bomb was used. An adequate arterial phase was achieved using the bolus track technique. Raw data were subsequently processed in a 190P Philips Brillance workstation at an average time of 30 minutes. Reconstructions were obtained with MIP and volumetric techniques.

Results:
Regarding arterial anatomic variants, we found prehilar bifurcations (n=3), accessory arteries (n=4) and polar arteries (n=9). Regarding venous variants, we found multiple renal veins (n=5), circumaortic veins (n=2), retroaortic veins (n=2) and prominent lumbar tributary vein (n=1).

Conclusion:
The renal vascular study is important, since it allows surgical planning in cases of partial or laparoscopic nephrectomies, and renal transplantation. Thus, the 64MDCT is a very useful non-invasive imaging tool, whose diagnostic efficacy and high accuracy are similar to those of digital angiography.

Key Words: AngioCT. Multidetector row CT. CT Angiography .

Resumo:
O adenocarcinoma prostático é o segundo tumor em incidência e mortalidade dentre as neoplasias malignas masculinas. Para adequada programação terapêutica é importante a distinção entre tumores confinados à próstata e aqueles com extensão extraprostática. Diferentes estudos têm demonstrado que a ressonância magnética da próstata com bobina endorretal auxilia no estadiamento local destes pacientes. Este artigo apresenta informações sobre a anatomia prostática, o aspecto tumoral à ressonância magnética, sinais de extensão tumoral extraprostática e invasão de vesículas seminais, sugestões de protocolo, princípios gerais e importância da espectroscopia de prótons, do estudo perfusional e da difusão, indicações da ressonância magnética na investigação de recidiva pós-operatória e pós-radioterapia, seu papel na detecção de lesões suspeitas em pacientes com suspeita clínico-laboratorial de adenocarcinoma prostático, além de apresentar os diagnósticos diferenciais e limitações do método.

Unitermos: Neoplasias da próstata; Adenocarcinoma; Imagem por ressonância magnética; Estadiamento de neoplasias.

Abstract
Prostate adenocarcinoma is the second tumor in incidence and mortality among malignant neoplasms in men. The differentiation between tumors confined to the organ and those with extraprostatic extension is critical for an appropriate therapeutic planning. Different studies have demonstrated that magnetic resonance imaging of the prostate with endorectal coil is useful in the local staging of these tumors. The present article presents information on the prostate gland anatomy, the tumor aspect at magnetic resonance imaging, specific signs of extracapsular extension and seminal vesicles invasion, protocol suggestions, general principles and relevance of proton spectroscopy, perfusion and diffusion imaging, role of magnetic resonance imaging in the postoperative and post-radiotherapy detection of local tumor recurrence, and also in the detection of lesions in patients with clinical/laboratory suspicion of prostate adenocarcinoma. Additionally, the present article describes differential diagnoses and limitations of the method.

Key Words: Prostate cancer; Adenocarcinoma; Magnetic resonance imaging; Cancer staging.

Objetivo:
Avaliar a espectroscopia de prótons e o estudo dinâmico do contraste por ressonância magnética na diferenciação dos tumores musculoesqueléticos benignos e malignos.

Materiais e Métodos:
Foram estudados 55 pacientes com tumores musculoesqueléticos (27 malignos e 28 benignos). Os exames foram realizados em aparelho de ressonância magnética de 1.5 T com protocolo convencional e espectroscopia de prótons com TE de 135 ms. O estudo dinâmico do contraste foi adquirido pela sequência T1 gradiente-eco após a administração intravenosa de gadolínio. Curvas de intensidade de sinal versus tempo e valores de slope foram calculados. A análise estatística foi realizada pelo teste de Levene, seguido pelo teste t de Student, além dos testes qui-quadrado de Pearson e exato de Fischer.

Resultados:
A sensibilidade, especificidade e acurácia da espectroscopia de prótons foram, respectivamente, de 87,5%, 92,3% e 90,9% (p < 0,0001). Além disso, houve significativa diferença entre o valor quantitativo da curva entre as lesões benignas (média de 27,5% por minuto) e malignas (média de 110,9% por minuto) (p < 0,0001).

Conclusão:
Os estudos quantitativo e qualitativo da análise dinâmica do contraste por ressonância magnética associados à presença do pico de colina são úteis na diferenciação dos tumores musculoesqueléticos em benignos e malignos.

Unitermos: Espectroscopia de prótons; Perfusão; Imagem por ressonância magnética.

Objective:
To assess the role of proton magnetic resonance spectroscopy and dynamic contrast-enhanced magnetic resonance imaging in the differentiation between malignant and benign musculoskeletal tumors.

Materials and Methods
Fifty-five patients with musculoskeletal tumors (27 malignant and 28 benign) were studied. The examinations were performed in a 1.5 T magnetic resonance scanner with standard protocol, and single voxel proton magnetic resonance spectroscopy with 135 msec echo time. The dynamic contrast study was performed using T1-weighted gradient-echo sequence after intravenous gadolinium injection. Timesignal intensity curves and slope values were calculated. The statistical analysis was performed with the Levene’s test, followed by a Student’s t-test, besides the Pearson’s chi-squared and Fischer’s exact tests.

Results
Proton magnetic resonance spectroscopy sensitivity, specificity and accuracy were, respectively, 87.5%, 92.3% and 90.9% (p < 0.0001). Statistically significant difference was observed in the slope (%/min) between benign (mean, 27.5%/min) and malignant (mean, 110.9%/min) lesions (p < 0.0001).

Conclusion
The time-intensity curve and slope values using dynamic-enhanced perfusion magnetic resonance imaging in association with the presence of choline peak demonstrated by single voxel magnetic resonance spectroscopy study are useful in the differentiation between malignant and benign musculoskeletal tumors.

Key Words: Proton magnetic resonance spectroscopy; Perfusion magnetic resonance imaging; Magnetic resonance imaging.

Objectivos:
establecer la concordancia entre la biopsia mediante aspiración con aguja fina y la biopsia con aguja TRuCuT 20g para el diagnóstico de nódulos tiroideos en pacientes remitidos para biopsia en la fundación santa fe de bogotá; determinar el rendimiento diagnóstico de cada uno de estos métodos de forma independiente y combinada, y establecer el porcentaje de complicaciones asociadas al procedimiento

Método:
se revisaron de forma retrospectiva los registros de 71 pacientes con biopsias simultáneas de tiroides con aguja fina y aguja TRuCuT durante el período 2003-2007. un patólogo y un citopatólogo analizaron de forma ciega e independiente las muestras de citología y de tejido que se habían obtenido y así clasificaron a los pacientes en: tejido tiroideo normal, lesiones benignas, anormal, lesiones de células foliculares y neoplasias malignas.

Resultados:
la concordancia entre la biopsia con aguja fina y la biopsia con aguja TRuCuT 20g fue baja. Cuando se compararon los reportes de patología y citología con los del espécimen quirúrgico, se encontró un mayor porcentaje de acuerdo en las biopsias con aguja fina, que clasificó correctamente 100% de los carcinomas, 100% de las lesiones de células foliculares y 62% de las lesiones benignas.

Conclusiones:
la concordancia entre la biopsia con aguja fina y con aguja TRuCuT es baja, por lo que no son intercambiables estos dos métodos diagnósticos. Aunque el rendimiento diagnóstico fue igual para ambos procedimientos de forma independiente, cuando se utilizaron en conjunto, se logró disminuir las muestras insuficientes a 0.

Palabras Clave: Glándula tiroides Ultrasonografía Biopsia con aguja fina

Summary:
We retrospectively reviewed medical records of 71 patients who underwent simultaneous fine needle and core biopsy of the thyroid gland at the fundacion santa fe de bogota ,during the period between 2003-2007.Citology and pathology samples were reviewed blindly by two independent observers (one cithophatologist and one pathologist). low agreement was found between the two methods. Kappa statistic was 0.351(0.22-0.249Ci95%). diagnostic performance was similar for both methods. The number of inadequate samples was 0% when both methods were combined. fine needle biopsy classified correctly 100% of the malignant lesions, 100% of the follicular lesions and 62% of the benign when compared with surgical specimens.

Key Words: Thyroid gland Ultrasonography Fine needle biopsy

Resumen:
Las lesiones focales del hígado en niños incluyen neoplasias, lesiones metastásicas, masas inflamatorias y quistes (congénitos o adquiridos); las neoplasias primarias —tanto benignas como malignas— representan del 1% al 2% de todos los tumores pediátricos. La mayoría de niños con tumores hepáticos benignos o malignos se presentan al examen físico con masa palpable. dentro del estudio por imágenes de ésta se encuentran incluidas múltiples modalidades, como ultrasonido, tomografía computarizada, resonancia magnética, angiografía y medicina nuclear. debido a que la resección quirúrgica es la principal opción de tratamiento para muchas de dichas lesiones, la descripción detallada de la extensión de la masa y sus relaciones anatómicas es esencial. en este artículo realizamos una revisión de las características imaginológicas de algunas lesiones focales hepáticas en niños.

Palabras Clave: Hemangioendotelioma Carcinoma hepatocelular Hiperplasia nodular focal Hepatoblastoma Seudotumor inflamatorio

Summary:
focal hepatic lesions in children include tumors, metastasis, inflammatory and cystic (both benign and acquired) lesions. primary hepatic tumors, both benign and malignant, constitute 1-2% of all pediatric neoplasms. the majority of children with benign or malignant hepatic tumors have a palpable mass at physical examination. imaging evaluation includes multiple modalities such as ultrasound, computed tomography, magnetic resonance, angiography and nuclear medicine. since surgical resection is the main therapeutic option in many of these lesions, a detailed description of the extension and anatomic relations of the mass is essential. in this article we review the imaging characteristics of focal hepatic lesions in children.

Key Words: Hemangioendothelioma Carcinoma hepatocellular Focal nodular hyperplasia Hepatoblastoma Granuloma, plasma cell

Resumen:
La tomografía computada multicorte permite obtener imágenes de alta resolución espacial y temporal además de reconstrucciones multiplanares y tridimensionales de gran calidad, lo que ha hecho que la Urografía por Tomografía Computada (UroTAC) se convierta en la técnica de elección para la evaluación del tracto urinario, reemplazando prácticamente a la urografía tradicional. En el Hospital Padre Hurtado, revisamos nuestra experiencia con UroTAC y técnica de “split bolus” que permite obtener simultáneamente una fase nefrográfica y excretora del sistema urinario mediante una sola adquisición, lo que disminuye la dosis de radiación al paciente, el número de imágenes y los costos de la UroTAC estándar. Presentamos una serie de 31 pacientes estudiados, describiendo la técnica y los principales hallazgos obtenidos en ellos.

Palabras Clave: Palabras clave: Aparato Genitourinario, Dosis de Radiación, UroTAC, Split bolus.

Summary:
Multislice computed tomography provides high spatial and temporal resolution images in addition to high quality multiplanar and three-dimensional reconstructions. As a result of this diagnostic efficacy, the Computed Tomography Urography (Uro-CT) has become the technique of choice for evaluating the urinary tract, virtually replacing the traditional urography examination. At Padre Hurtado Hospital, Santiago, Chile, we conducted a retrospective analysis to review our experience with Uro-CT scanning and split bolus technique, which has the potential to yield a synchronous nephrographic and excretory phase of the urinary system, thus reducing radiation dose for patients, number of images and costs generated by MDCT urography. A series of 31 cases is presented, along with description of techniques applied as well as study main findings.

Key Words:Genitourinary system, Radiation dosage, Split bolus, Urography computed tomography.

Resumen:
La insuficiencia venosa se define como una alteración en el retorno venoso, que compromete el sistema superficial, profundo o ambos, cuya causa puede ser alteración en la bomba muscular, obstrucción venosa, incompetencia valvular o falla cardíaca derecha. Se traduce en una hipertensión venosa dinámica que se manifiesta a través del desarrollo de várices, o cambios tróficos de la piel. La insuficiencia superficial se debe a la presencia de shunts veno-venosos, que consisten en cortocircuitos en que se pierde flujo desde el sistema profundo a través de un punto de fuga y luego regresa por otro punto de entrada. El estudio se realiza de pie, estimulando la bomba muscular a través de distintas maniobras o aumentando la presión central con Valsalva. El mapeo es la expresión gráfica del estudio, y debe demostrar el tipo de shunt, localización y patrón varicoso.

Palabras Clave: Insuficiencia venosa, Doppler venoso

Summary:
Venous insufficiency is defined as an impaired venous return, which affects the superficial or the deep system, or both.This condition may becaused either by an alteration in the muscle pump, a venous obstruction, a valvular incompetence or right-sided heart failure. It translates into a dynamic venous hypertension manifested through the development ofvaricose veins or trophic skin changes. The surface failure is due to the presence of veno-venous shunts which provoke a flow loss from thedeep system through a vanishing point and then returns through another entry point. The study is performed with the patient in standing position, stimulating muscle pump through various exercises or increasing central pressure with Valsalva maneuver. The mapping is a graphic expression of the study, and it must show the type of shunt, location and pattern of varicose veins.

Key Words: Venous Doppler exam, Venous insufficiency, Venous mapping, Veno-venous shunts, Ultrasound.

Resumen:
El cáncer de recto es una neoplasia con elevada incidencia en nuestro medio. Las distintas opciones terapéuticas que podrán aplicarse en cada caso van a depender fundamentalmente de la extensio´n que presente el tumor en el momento del diagnóstico. Por esto, los radiólogos tenemos un papel central en su tratamiento. En el presente texto se discuten la técnica radiológica óptima, algunos aspectos anatómicos fundamentales y la semiología aceptada en la interpretación de los distintos estudios de imagen que se realizan a estos pacientes, además de su rendimiento, y una visión general del pronóstico y de las distintas opciones terapéuticas. Su conocimiento es muy útil para participar en equipos formados por diferentes especialistas y comprender la trascendencia de la información aportada por la interpretación de los estudios que realizamos a estos pacientes.

Palabras Clave: Cáncer de recto; Estadificación; Pruebas de imagen

Summary:
Rectal cancer has a high incidence in our area. The different treatment options that can be used in each case depend fundamentally on the extension of the tumor at the time of diagnosis.Thus,radiologists have a central role in the management of this disease.Wediscuss the optimum imaging technique for staging rectal cancer, some fundament al histologic al aspects, and the accepted semiology in the interpretation of different imaging studies carried out in the se patients, as well as the diagnostic performance of each technique .We provide a general overview of the prognosis and different treatment options. This knowledge is very useful for radiologists participating in multidisci plinary teams and for understanding the transcendence of the information provided by image interpretati on in these patients.

Key Words: Rectal cancer; Staging; Imaging studies