Dual-energy CT: Technical considerations and clinical applications.

Although dual-energy CT was initially described by Hounsfield in 1973, it remains underused in clinical practice. It is therefore important to emphasize the clinical benefits and limitations of this technique. Iodine mapping makes it possible to quantify the uptake of iodine, which is very important in characterizing tumors, lung perfusion, pulmonary nodules, and the tumor response to new treatments. Dual-energy CT also makes it possible to obtain virtual single-energy images and virtual images without iodinated contrast or without calcium, as well as to separate materials such as uric acid or fat and to elaborate hepatic iron overload maps. In this article, we review some of the clinical benefits and technical limitations to improve understanding of dual-energy CT and expand its use in clinical practice.

Energía Dual en TC. Consideraciones técnicas y aplicaciones clínicas / Dual-energy CT: technical considerations and clinical applications

A pesar de que el concepto de doble energía en TC nace con Hounsfield en 1973, su uso clínico permanece infrautilizado, siendo importante incidir en los beneficios clínicos y limitaciones de esta técnica. La utilidad de imágenes de «mapa de yodo» permite valorar cuantitativamente la captación de yodo, de gran importancia en la caracterización de lesiones tumorales, en los mapas de perfusión pulmonar, en la naturaleza del nódulo pulmonar o en la respuesta tumoral a los nuevos tratamientos. Permite la obtención de imágenes monoenergéticas virtuales, imágenes virtuales sin contraste yodado o sin calcio, separación de materiales como ácido úrico o de la grasa o mapas de sobrecarga férrica hepática. En este artículo revisamos algunos de los beneficios clínicos y limitaciones técnicas para mejorar su comprensión y ayudar a expandir su uso clínico.(AU)

Although dual-energy CT was initially described by Hounsfield in 1973, it remains underused in clinical practice. It is therefore important to emphasize the clinical benefits and limitations of this technique. Iodine mapping makes it possible to quantify the uptake of iodine, which is very important in characterizing tumors, lung perfusion, pulmonary nodules, and the tumor response to new treatments. Dual-energy CT also makes it possible to obtain virtual single-energy images and virtual images without iodinated contrast or without calcium, as well as to separate materials such as uric acid or fat and to elaborate hepatic iron overload maps. In this article, we review some of the clinical benefits and technical limitations to improve understanding of dual-energy CT and expand its use in clinical practice.(AU)

SARS-CoV-2: what it is, how it acts, and how it manifests in imaging studies. / SARS-CoV-2: cómo es, cómo actúa y cómo se expresa en la imagen.

COVID-19 is a disease with many clinical, biochemical, and radiological signs that has a predilection for the lungs, probably because of the high number of ACE-2 receptors in this organ. The infection of cells activates proinflammatory substances, causing diffuse alveolar damage, which is the histopathological basis of ARDS. The exudative phase would manifest as ground-glass opacities and consolidation, and the proliferative phase would manifest as a tendency toward a more linear morphology. Both CT and PET/CT findings support the inflammatory character of the lung lesions in the initial phase of the disease and in patients with mild-moderate disease. Severe cases have pulmonary hypoperfusion that is likely due to abnormal alveolar ventilation and perfusion. On the other hand, a prothrombotic state increases the risk of thromboembolic disease through the activation of coagulation and platelet pathways with the production of fibrin degradation products (D-dimer) and consumption of platelets.

SARS-CoV-2: cómo es, cómo actúa y cómo se expresa en la imagen / SARS-CoV-2: what it is, how it acts, and how it manifests in imaging studies

La COVID-19 es una enfermedad con una gran semiología clínica, bioquímica y radiológica, que tiene una afectación preferente por el pulmón, probablemente debido a un mayor número de receptores ECA-2. La infección celular activa sustancias proinflamatorias y provoca un daño alveolar difuso, que es la base histopatológica del distrés respiratorio del adulto. La fase exudativa explicaría las imágenes "en vidrio deslustrado" y consolidación, mientras que la tendencia hacia una morfología más lineal representa la fase proliferativa. Tanto la tomografía computarizada (TC) como la tomografía por emisión de positrones/ tomografía computarizada (PET/TC) apoyan el carácter inflamatorio de las lesiones pulmonares cuando la enfermedad está en fase inicial o es leve-moderada. Los casos graves muestran una hipoperfusión pulmonar que se explicaría por una alteración de la ventilación-perfusión alveolar (V/Q). Por otro lado, un estado protrombótico conlleva mayor probabilidad de enfermedad tromboembólica por la activación de la vía de la coagulación y plaquetaria, con la producción de sustancia de degradación de la fibrina (dímero D) así como el consumo de plaquetas

COVID-19 is a disease with many clinical, biochemical, and radiological signs that has a predilection for the lungs, probably because of the high number of ACE-2 receptors in this organ. The infection of cells activates proinflammatory substances, causing diffuse alveolar damage, which is the histopathological basis of ARDS. The exudative phase would manifest as ground-glass opacities and consolidation, and the proliferative phase would manifest as a tendency toward a more linear morphology. Both CT and PET/CT findings support the inflammatory character of the lung lesions in the initial phase of the disease and in patients with mild-moderate disease. Severe cases have pulmonary hypoperfusion that is likely due to abnormal alveolar ventilation and perfusion. On the other hand, a prothrombotic state increases the risk of thromboembolic disease through the activation of coagulation and platelet pathways with the production of fibrin degradation products (D-dimer) and consumption of platelets

Resultados a medio plazo de la artroplastia total de cadera metal-metal con cabeza de gran tamaño Magnum / Midterm results of Magnum large head metal-on-metal total hip arthroplasty

Objetivos: A raíz de las alertas sanitarias surgidas por la alta incidencia de recambios en la artroplastia de cadera metal-metal, se presentan los resultados obtenidos del seguimiento prospectivo de la serie de nuestro centro con cabezas de gran tamaño. Material y métodos: Se incluyeron todos los pacientes tratados con el cotilo Recap-M2a-Magnum, Biomet de 2008 a 2011. Se revisaron prospectivamente todos los pacientes registrando Harris Hip Score y síntomas de intoxicación por cromo-cobalto y se solicitaron niveles séricos de estos iones, radiografía y ecografía. Se solicitó resonancia magnética en caso de ecografía positiva. Resultados: Se incluyeron 26 varones de 48,54 años de edad media [32-62, DE: 7,18]. Se utilizó un abordaje anterolateral y vástagos Bimetric (7) o F40 (19). La moda de los diámetros cefálicos fue 46 [42-52]. La inclinación media del cotilo fue 39,35° [21-59°, DE: 9,78]. Durante el seguimiento (7,3 años [5,9-9,4 años, DE: 0,78]), 3 pacientes (11,5%) precisaron revisión (2 por movilización aséptica, un pseudotumor). El tiempo medio hasta la revisión fue 5,4 años [3,1-8,0, DE: 2,48]. La probabilidad acumulada de supervivencia fue del 88,5% (IC95% 76,3-100%). El Harris Hip Score fue de 94,47 [66,5-100, DE: 8,94] y los pacientes no mostraron ningún síntoma de intoxicación metálica, con niveles de cromo 1,88 mcg/dl [0,6-3,9] y cobalto 1,74 mcg/dl [0,5-5,6]. Se encontró un pseudotumor en un paciente asintomático y pequeñas cantidades de líquido periprotésico en 5 pacientes (19,2%). Discusión y conclusiones: Seguimos encontrando altas tasas de revisión al extender el seguimiento de los pacientes debido a la movilización aséptica y la formación de pseudotumores. La resonancia nuclear magnética no parece la prueba más adecuada para el estudio de las complicaciones de este tipo de prótesis

Objectives: We present the results of the prospective follow up of a sample of large head metal-metal total hip arthroplasty obtained after the safety alert regarding a higher incidence of revision of these implants. Material and methods: All patients implanted with the Recap-M2a-Magnum cup between 2008 and 2011 were included. They were prospectively reviewed recording Harris Hip Score, clinical symptoms of chromium or cobalt intoxication. Serum levels of these ions were requested as well as X-Rays and ultrasonography. An MRI was performed in the cases of positive ultrasonography. Results: Twenty-six males with a mean age of 48.54 years [32-62, SD: 7.18] were included. An anterolateral approach and Bi-Metric (7) and F-40 (19) stems were used. Cephalic diameters ranged 42-52 (mode: 46) and the mean cup inclination was 39.35° [21-59°, SD: 9.78]. During follow-up (7.3 years [5.9-9.4; SD: .78]), 3 patients (11.5%) underwent revision (2 cases aseptic loosening, 1 pseudotumour). Mean time until revision was 5.4 years [3.1-8.0; SD: 2.48]. The accumulated survival probability was 88.5% (95% CI 76.3-100%). Harris Hip Score was 94.47 [66.5-100; SD: 8.94] and the patients showed no metallic intoxication symptoms. The levels of chromium were 1.88 mcg/dl [0.6-3.9] and cobalt 1,74 mcg/dl [0.5-5,6]. One pseudotumour was found in an asymptomatic patient, and small amounts of periarticular liquid were found in 5 patients (19.2%) Discussion and conclusions: High revision rates are still found when follow up is extended due to aseptic loosening and pseudotumour formation. MRI might not be the most adequate test to study the complications of these prostheses

Midterm results of Magnum large head metal-on-metal total hip arthroplasty. / Resultados a medio plazo de la artroplastia total de cadera metal-metal con cabeza de gran tamaño Magnum.

OBJECTIVES: We present the results of the prospective follow up of a sample of large head metal-metal total hip arthroplasty obtained after the safety alert regarding a higher incidence of revision of these implants. MATERIAL AND METHODS: All patients implanted with the Recap-M2a-Magnum cup between 2008 and 2011 were included. They were prospectively reviewed recording Harris Hip Score, clinical symptoms of chromium or cobalt intoxication. Serum levels of these ions were requested as well as X-Rays and ultrasonography. An MRI was performed in the cases of positive ultrasonography. RESULTS: Twenty-six males with a mean age of 48.54 years [32-62, SD: 7.18] were included. An anterolateral approach and Bi-Metric (7) and F-40 (19) stems were used. Cephalic diameters ranged 42-52 (mode: 46) and the mean cup inclination was 39.35° [21-59°, SD: 9.78]. During follow-up (7.3 years [5.9-9.4; SD: .78]), 3 patients (11.5%) underwent revision (2 cases aseptic loosening, 1 pseudotumour). Mean time until revision was 5.4 years [3.1-8.0; SD: 2.48]. The accumulated survival probability was 88.5% (95% CI 76.3-100%). Harris Hip Score was 94.47 [66.5-100; SD: 8.94] and the patients showed no metallic intoxication symptoms. The levels of chromium were 1.88 mcg/dl [0.6-3.9] and cobalt 1,74 mcg/dl [0.5-5,6]. One pseudotumour was found in an asymptomatic patient, and small amounts of periarticular liquid were found in 5 patients (19.2%) DISCUSSION AND CONCLUSIONS: High revision rates are still found when follow up is extended due to aseptic loosening and pseudotumour formation. MRI might not be the most adequate test to study the complications of these prostheses.

Resonancia magnética en la planificación de la braquiterapia intracavitaria para el tratamiento del cáncer de cérvix localmente avanzado / Magnetic resonance imaging for planning intracavitary brachytherapy for the treatment of locally advanced cervical cancer

El cáncer de cérvix es el tercer cáncer ginecológico más frecuente. El tratamiento depende de la estadificación del tumor en el momento del diagnóstico, siendo la combinación de quimioterapia y radioterapia el tratamiento de elección para cánceres localmente avanzados. El uso combinado de radioterapia externa y braquiterapia aumenta la supervivencia en estas pacientes. La braquiterapia permite proporcionar mayor dosis de radiación al tumor con menor toxicidad de los tejidos vecinos en comparación con la radioterapia externa exclusiva. La planificación de la braquiterapia se ha realizado durante años exclusivamente con tomografía computarizada (TC). La reciente incorporación de la resonancia magnética (RM) ha demostrado que aporta información esencial del tumor y de las estructuras vecinas, y permite definir mejor los volúmenes blanco. No obstante, la RM presenta limitaciones, algunas de las cuales se pueden compensar con la fusión de imágenes de TC y RM, con lo que se consigue una planificación óptima al combinar las ventajas de cada técnica (AU)

Cervical cancer is the third most common gynecological cancer. Its treatment depends on tumor staging at the time of diagnosis, and a combination of chemotherapy and radiotherapy is the treatment of choice in locally advanced cervical cancers. The combined use of external beam radiotherapy and brachytherapy increases survival in these patients. Brachytherapy enables a larger dose of radiation to be delivered to the tumor with less toxicity for neighboring tissues with less toxicity for neighboring tissues compared to the use of external beam radiotherapy alone. For years, brachytherapy was planned exclusively using computed tomography (CT). The recent incorporation of magnetic resonance imaging (MRI) provides essential information about the tumor and neighboring structures making possible to better define the target volumes. Nevertheless, MRI has limitations, some of which can be compensated for by fusing CT and MRI. Fusing the images from the two techniques ensures optimal planning by combining the advantages of each technique (AU)

Magnetic resonance imaging for planning intracavitary brachytherapy for the treatment of locally advanced cervical cancer.

Cervical cancer is the third most common gynecological cancer. Its treatment depends on tumor staging at the time of diagnosis, and a combination of chemotherapy and radiotherapy is the treatment of choice in locally advanced cervical cancers. The combined use of external beam radiotherapy and brachytherapy increases survival in these patients. Brachytherapy enables a larger dose of radiation to be delivered to the tumor with less toxicity for neighboring tissues with less toxicity for neighboring tissues compared to the use of external beam radiotherapy alone. For years, brachytherapy was planned exclusively using computed tomography (CT). The recent incorporation of magnetic resonance imaging (MRI) provides essential information about the tumor and neighboring structures making possible to better define the target volumes. Nevertheless, MRI has limitations, some of which can be compensated for by fusing CT and MRI. Fusing the images from the two techniques ensures optimal planning by combining the advantages of each technique.