Assuntos
Aneurisma Roto/diagnóstico , Aorta Abdominal/lesões , Aneurisma da Aorta Abdominal/diagnóstico , Fístula Intestinal/diagnóstico , Neoplasias Uterinas/diagnóstico , Idoso , Aneurisma Roto/patologia , Aneurisma Roto/cirurgia , Aorta Abdominal/cirurgia , Aneurisma da Aorta Abdominal/patologia , Aneurisma da Aorta Abdominal/cirurgia , Duodeno/patologia , Duodeno/cirurgia , Evolução Fatal , Feminino , Hemorragia Gastrointestinal/etiologia , Hemorragia Gastrointestinal/patologia , Hemorragia Gastrointestinal/cirurgia , Humanos , Fístula Intestinal/complicações , Fístula Intestinal/patologia , Fístula Intestinal/cirurgia , Metástase Linfática , Neoplasias Uterinas/patologia , Útero/patologiaRESUMO
Changes in x-ray attenuating tissue caused by lung disorders like emphysema or fibrosis are subtle and thus only resolved by high-resolution computed tomography (CT). The structural reorganization, however, is of strong influence for lung function. Dark-field CT (DFCT), based on small-angle scattering of x-rays, reveals such structural changes even at resolutions coarser than the pulmonary network and thus provides access to their anatomical distribution. In this proof-of-concept study we present x-ray in vivo DFCTs of lungs of a healthy, an emphysematous and a fibrotic mouse. The tomographies show excellent depiction of the distribution of structural - and thus indirectly functional - changes in lung parenchyma, on single-modality slices in dark field as well as on multimodal fusion images. Therefore, we anticipate numerous applications of DFCT in diagnostic lung imaging. We introduce a scatter-based Hounsfield Unit (sHU) scale to facilitate comparability of scans. In this newly defined sHU scale, the pathophysiological changes by emphysema and fibrosis cause a shift towards lower numbers, compared to healthy lung tissue.
Assuntos
Tomografia Computadorizada por Raios X/métodos , Animais , Feminino , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Pneumopatias/diagnóstico por imagem , Pneumopatias/patologia , Camundongos , Modelos AnimaisRESUMO
Novel radiography approaches based on the wave nature of x-rays when propagating through matter have a great potential for improved future x-ray diagnostics in the clinics. Here, we present a significant milestone in this imaging method: in-vivo multi-contrast x-ray imaging of a mouse using a compact scanner. Of particular interest is the enhanced contrast in regions related to the respiratory system, indicating a possible application in diagnosis of lung diseases (e.g. emphysema).
Assuntos
Diagnóstico por Imagem/métodos , Animais , Meios de Contraste/química , Pneumopatias/diagnóstico , Camundongos , Radiografia , Sistema Respiratório/diagnóstico por imagem , Raios XRESUMO
In clinically established-absorption-based-biomedical x-ray imaging, contrast agents with high atomic numbers (e.g. iodine) are commonly used for contrast enhancement. The development of novel x-ray contrast modalities such as phase contrast and dark-field contrast opens up the possible use of alternative contrast media in x-ray imaging. We investigate using ultrasound contrast agents, which unlike iodine-based contrast agents can also be administered to patients with renal impairment and thyroid dysfunction, for application with a recently developed novel x-ray dark-field imaging modality. To produce contrast from these microbubble-based contrast agents, our method exploits ultra-small-angle coherent x-ray scattering. Such scattering dark-field x-ray images can be obtained with a grating-based x-ray imaging setup, together with refraction-based differential phase-contrast and the conventional attenuation contrast images. In this work we specifically show that ultrasound contrast agents based on microbubbles can be used to produce strongly enhanced dark-field contrast, with superior contrast-to-noise ratio compared to the attenuation signal. We also demonstrate that this method works well with an x-ray tube-based setup and that the relative contrast gain even increases when the pixel size is increased from tenths of microns to clinically compatible detector resolutions about up to a millimetre.