RESUMEN
The mediastinal lines visible at conventional radiography represent the interfaces between the mediastinum and adjacent lung parenchyma. Preservation, obliteration, thickening and distortion of these lines represent the key to detecting and localising mediastinal abnormalities on chest radiographs. The learning objectives of this review are to: illustrate radiographic anatomy of the mediastinum with particular attention to mediastinal lines; describe radiographic signs that allow identification of mediastinal abnormalities that are difficult to detect on conventional chest radiographs; describe findings that help localise abnormalities in the anterior, middle or posterior mediastinum. The anterior junction line obliteration, the hilum overlay sign, the preservation of the posterior mediastinal lines and the silhouette sign with the right cardiac border are radiographic signs that allow identification and localisation of anterior mediastinal lesions. Widening of the right paratracheal stripe, distortion of the azygo-oesophageal recess and the convex border of the aortopulmonary window indicate the presence of a middle mediastinal abnormality. Thickening, distortion or disruption of paraortic and paraspinal lines and posterior junction line obliteration are caused by posterior mediastinal lesions. Knowledge of normal radiographic mediastinal anatomy and mediastinal lines is crucial to identifying subtle mediastinal abnormalities that can be easily missed on conventional radiography. Moreover, this approach allows identification of the involved mediastinal compartment on chest radiographs, thereby directing the most appropriate further diagnostic workup.
Asunto(s)
Enfermedades del Mediastino/diagnóstico por imagen , Neoplasias del Mediastino/diagnóstico por imagen , Mediastino/diagnóstico por imagen , Radiografía Torácica , Adolescente , Adulto , Femenino , Humanos , Pulmón/diagnóstico por imagen , Masculino , Mediastino/anatomía & histología , Persona de Mediana EdadRESUMEN
To assess the value of spiral computed tomography (CT) with multiplanar reformations for detection of neoplastic extension across pulmonary fissures, 51 patients with a lung neoplasm near a fissure underwent spiral CT, followed by multiplanar reformations, and spaced thin-section CT scans through the area of contact between tumor and fissure. The CT studies were evaluated for visibility of fissures and their relationship to the tumor. Imaging findings were compared with surgical results in 31 patients who underwent thoracotomy. Visibility of fissures on multiplanar reformations was either good or acceptable in 47 (92.2%) patients, and poor in four. Surgical findings of neoplastic extension across the major or the minor fissure were present in seven and eight patients, respectively. Thin-section CT scans were 83.3% sensitive in assessing neoplastic involvement of the major fissure, axial CT scans were 57.1% sensitive, and spiral CT multiplanar images were 100% sensitive. In the evaluation of the minor fissure, thin-section CT and axial spiral CT scans were considered inconclusive in six patients whereas multiplanar reformations enabled correct assessment of the fissure/neoplasm relationship in all but one patient. Spiral CT multiplanar images are accurate for detection of transfissural neoplastic extension, and are superior to axial CT scans for evaluation of tumors near the minor fissure.
Asunto(s)
Neoplasias Pulmonares/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Anciano , Anciano de 80 o más Años , Reacciones Falso Positivas , Femenino , Humanos , Pulmón/anatomía & histología , Pulmón/diagnóstico por imagen , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/cirugía , Masculino , Persona de Mediana Edad , Sensibilidad y EspecificidadRESUMEN
This work was aimed at optimizing the spiral CT technique in studying the trachea to obtain multiplanar reconstructions with high diagnostic yield. The authors tried to identify an image reconstruction technique, on both the coronal and the sagittal planes, to visualize the whole trachea on a single image in each patient. Twenty patients, 15 with pathologic tracheal involvement and 5 with pulmonary lesions with no tracheal involvement, were examined with a Somatom Plus CT unit (spiral technique: 120 kV, 210 mA, 5-mm slices, 5-mm/s table feed and 24-s scanning time). Multiplanar reconstructions were obtained on the oblique plane, identified by three axial reference scans at different levels. The whole trachea was reconstructed on a single image in 100% of cases on the coronal plane and in 95% of cases on the sagittal plane. Image quality was good in 16 patients and acceptable in 4. The authors stress the value of spiral CT multiplanar images when the reconstruction plane lies in the tracheal lumen on both the coronal and the sagittal planes.
Asunto(s)
Procesamiento de Imagen Asistido por Computador , Tomografía Computarizada por Rayos X/métodos , Tráquea/diagnóstico por imagen , Enfermedades de la Tráquea/diagnóstico por imagen , Quistes/diagnóstico por imagen , Estudios de Evaluación como Asunto , Femenino , Bocio Subesternal/diagnóstico por imagen , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Masculino , Estenosis Traqueal/diagnóstico por imagenRESUMEN
Spiral computed tomography (CT) allows very satisfactory temporal resolution for the detection and analysis of changes in contrast medium density, so that volumes of contrast material smaller than those recommended for conventional CT can be used. The present double-blind, parallel group study was designed to compare image quality and diagnostic efficacy obtained with two different iodine strengths (200 and 300 mgI/ml) and two different flow rates (2 and 3 ml/s) of a fixed volume (70 ml) of iomeprol in adult consenting patients requiring spiral CT of the mediastinum. Imaging was performed during suspended respiration and, a 15-s delay to scan. Spiral CT was initiated 1 cm above the aortic arch and continued inferiorly for 24 cm in all patients. Two independent readers blindly graded image quality, opacification of the superior vena cava, thoracic aorta and pulmonary arteries, and overall diagnostic quality of the CT examination. CT density measurements were performed over the level of the aortic arch, left and right pulmonary arteries, left atrium, and descending aorta. Opacification of the mediastinal vessels was better in the patients injected at 3 ml/s flow rate and was independent of the iodine strength used, except in the case of the thoracic aorta, which was better opacified by injecting iomeprol 300 mgI/ml at 3 ml/s. The highest diagnostic efficacy of the spiral CT examination was obtained with iomeprol 300 mgI/ml at 3 ml/s infusion rate, which seems to represent the administration scheme of choice.