Chest X-Ray: the essentials

Transcription

1 Chest X-Ray: the essentials Poster No.: C-1264 Congress: ECR 2017 Type: Educational Exhibit Authors: J. J. Delgado Moraleda, A. ALEGRE DELGADO, R. M. Piqueras Olmeda, E. Chacón Avilés, J. F. Melo Villamarín, A. Vizarreta Figueroa; Valencia/ES Keywords: Anatomy, Lung, Mediastinum, Conventional radiography, Digital radiography, CT, Screening, Normal variants, Localisation, Acute, Trauma, Atelectasis DOI: /ecr2017/C-1264 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 66

2 Learning objectives Describe the systematic interpretation of chest x-ray and titratable anatomic structures that can be assessed using this test.. Review the different techniques and projections, taking into account advantages and limitations. Explain and illustrate the most common findings of thoracic pathology and false images that mimic pathology. Background Chest x-ray is the most demanded radiological test in the emergency department. Therefore, to know the most frequent pathology will guide the diagnosis and the request of specific tests that allow the characterization of pathology. Findings and procedure details The following work is organized according to these structures and the most frequent findings that are usually found on chest radiography. The sections are: Pathology of the pulmonary parenchyma. Pleural pathology. Mediastinal pathology. Pathology of the chest wall. LUNG PARENCHYMA The assessment of lung parenchyma is the main objective of the chest x-ray. For proper assessment it is necessary to know the pulmonary anatomy both at macroscopic and microscopic level. Pulmonary components and radiological patterns Page 2 of 66

3 There are two types of components in the lung. The interstititum is the network support tissue of the lung. It consists of connective tissue traversed by blood and lymph vessels. The alveoli are physiologically airfilled spaces that are grouped to form acini. A set of acini form a lung lobe. As physiologically contain air, they are not seen on xray, and occupation means pathology. Therefore, the pathology can be classified as affecting one or other of these two components. As a result, there are two types of radiological patterns of lung disease on chest radiograph. Interstitial pattern. It consists of a selective involvement of the pulmonary interstitium. The alveoli remain filled with air and its appearance is a normally aerated lung but with a marked vascularity too. The most common cause of this pattern in the urgency is cardiogenic pulmonary edema. The characteristic radiologic findings of this entity are congestive pulmonary hila and increased interstitial pattern, especially lines B of Kerley. In these cases, it can also appear pleural effusion, which is more frequent in the right costophrenic angle. The findings described are shown in the following images. Page 3 of 66

4 Fig. 1 References: - Valencia/ES Page 4 of 66

5 Fig. 2 References: - Valencia/ES Alveolar pattern. It is produced by liquid occupation of the airspace contained in the pulmonary alveoli. The disease that causes most frequently alveolar pattern in the urgency department are respiratory infections. Another very frequent diagnostic possibilities are atelectasis or nodules / masses. The differential diagnosis between these entities is very difficult. In order to differentiate them, it will be necessary to complete the study with a CT or evaluate the radiological evolution. Some characteristic radiographic signs appearing in such pathologies are the air bronchogram sign or the silhouette sign. Air bronchogram sign. The healthy lung is seen as a predominantly radiolucent tissue because its main component is the air. It highlights some white crosslinked form the interstitial space. Bronchial branches can not be distinguished because they contain air, like the rest of the lung. Being "air on air" are not visible. In contrast, when the cells are occupied by any liquid substance density, density increase. If the bronchial ramifications are filled with air, they stand out like a black grid on white background. Page 5 of 66

6 Silhouette sign. If two structures having the same radiographic density are in contact, effacement of its edges is seen, that is, you can not know where a structure ends and the other one starts. This sign is very useful to know where a consolidation or a mass is located. The following illustrations radiographs of patients diagnosed with pneumonia and how the sign silhouette allows its location. Sometimes this is not enough and it is necessary to use the posteroanterior and lateral projections for better localization of the lesion. Fig. 3 References: - Valencia/ES Page 6 of 66

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11 Fig. 8 References: - Valencia/ES Sometimes the entity that produces the alveolar pattern is too subtle and not produce any of these signs. One way to find out its location is superimposed to the spine in lateral projection. In healthy individuals, the lower vertebrae must be more radiolucent that the higher ones because on the lower part of the thorax there is more amount of air. If the lower vertebrae are more radiopaque than the upper, this is indicative that there is injury that is producing this increase in density (for example, a consolidation). An entity that is frequently observed in emergency departments is cystic fibrosis.these patients usually consult for superinfection. In the picture below, it is also seen an increase of the retrosternal clear space and retrocardiac space due to air trapping. When the airways are obstructed by mucus, it is not possible to adequately expire. This results in a progressive air retention, shown in the radiograph as a bilateral pulmonary hyperlucency of those spaces. Page 11 of 66

12 Fig. 9 References: - Valencia/ES Bronchiectasis and tuberculosis produce a similar phenomenon. If an Xray is done to a patient free of acute lung disease, a hyperlucency of lung segments affected by bronchiectasis or tuberculosis is observed. However, if an infection occurs, the air spaces can be filled with mucus or pus. It is the case of the examples shown below. Page 12 of 66

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14 Fig. 11 References: - Valencia/ES Pulmonary infectious diseases not only manifests as alveolar consolidations, but also can manifest as small airway involvement. It is the case of bronchiolitis. In the chest radiography, the characteristic finding is the thickening of the peribronchial cuf. Page 14 of 66

15 Fig. 12 References: - Valencia/ES Nodules or masses. Although it is a completely different, lung infections often cause problems of differential diagnosis with consolidations and atelectasis. This occurs because the density of the proliferating tissues is equal to that of water. However, often they appear at the same time: masses, atelectasis and superinfections as consolidation. This is due to the invasion of the airway by a nodule or mass, resulting atelectasis or obstructive consolidation superinfection of a poorly aerated airspace. Overlapping structures, such as ribs, make more difficult the diagnosis of pulmonary nodules. Occasionally, it is necessary to repeat the radiography with a different angulation to avoid this problem (for example using the lordotic projection for the diagnosis of pulmonary nodules affecting the apex). Page 15 of 66

16 Fig. 13 References: - Valencia/ES There are also entities that cause widening of the mediastinum and, in some cases, it may be confused with a mass. It is the case of the example shown below, in which an aortic aneurysm was at first confused with a lung mass. CT scanning allowed a definitive diagnosis. Page 16 of 66

17 Fig. 14 References: - Valencia/ES MEDIASTINAL PATHOLOGY In the mediastinum there are many lines and each one represents an anatomical structure. An exhaustive analysis exceeds the objective of this work. However, we will see the changes found more frequently in urgency. Elongation and aortic aneurysm. Elongation is an anatomical manifestation of hypertension. Given the high prevalence in the elderly population of hypertension, it is very common to find aortic elongation on chest X-ray. However, an excessive mediastinal widening and a rounded morphology should suggest the diagnosis of aneurysm. Page 17 of 66

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19 Fig. 16 References: - Valencia/ES Valve prostheses and pacemakers. Sometimes, either because the patient belongs to another health territory and clinic history is not accessible or because history can not be properly performed, it is not possible to know exactly the devices that the patient. It is therefore important to describe them. In the case of prosthetic valves, it is important to indicate its position. The most common are located in the left valves. To differentiate them, it is useful to look at its location, its orientation and arrangement adopting the leaflets during opening. 1. As for the location, mitral valvular prostheses located inferiorly to the aortic given the anatomical arrangement of the valves. As for the orientation, usually the mitral valves are perpendicular to the posteroanterior (so a circle is seen) and parallel to the lateral projection (so are shaped line). For aortic valves opposite happens. 2. Page 19 of 66

20 With regard to the opening of the valves, since the mitral valve opens caudally and aortic valves cranially, if matches the acquisition of X-ray was performed with open valves, these may look pointing in the direction of blood flow. Fig. 17 References: - Valencia/ES Pathology caused by external structures. Some structures may invade the mediastinum. It is the case of endothoracic goiters. They correspond to overexpansion of the thyroid gland which usually are limited to neck, but endothoracic goiters invade the mediastinum. As a result, differential diagnosis should include lung or mediastinal pathology, as shown in the image. In this case, the large mass produce a displacement of mediastinal structures, such as the trachea. Page 20 of 66

21 Fig. 18 References: - Valencia/ES Esophageal disease. The most frequent urgency is hiatal hernia. It causes an aerial retrocardiac image, best seen on the lateral radiograph. Page 21 of 66

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23 Fig. 20 References: - Valencia/ES At the emergency department is also possible to diagnose esophageal tumor pathology, which is vital for the patient, as shown in the example. Page 23 of 66

24 Fig. 21 References: - Valencia/ES Hilar lymphadenopathy. Causing thickening and irregularity of the mediastinal silhouette. They can be a sign of local or systemic pathology. In the examples shown postoperative local pathology, such as lung tumor, but also systemic diseases, such as sarcoidosis. Page 24 of 66

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27 Fig. 24 References: - Valencia/ES Pneumomediastinum. It is the presence of air within the mediastinum. Sometimes accompanied by a pneumothorax or subcutaneous emphysema, as in the example. PLEURAL PATHOLOGY The pleura consists of two layers known as visceral pleura and parietal pleura. Between them there is a cavity usually filled with a minimal amount of liquid: it is called pleural cavity. This liquid has the function the motion of the lungs does not generate friction with the ribcage. Pleural effusion. Excessive accumulation of fluid in the cavity is known as pleural effusion. Pathognomonic radiological sign of this is the appearance of meniscus sign, which is caused by the morphology adopted the liquid within the cavity due to gravity. This sign is visible in the visible in the standing and Page 27 of 66

28 sitting-up radiograph. If done in decubitus, pleural effusion will manifest as a diffuse opacification of the affected hemithorax. Fig. 25 References: - Valencia/ES Small pleural effusion not produce the sign of the meniscus and will manifest simply as an occupation of the costophrenic angle. Pneumothorax. It is produced by the introduction of air into the pleural cavity, which takes off the pleural layers and produces a partial or total collapse of the underlying lung parenchyma. Radiographic signs that detect this entity are the detection of the pleural line, this hyperlucency chamber absence of pneumothorax and interstitial pattern in it. Page 28 of 66

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30 Fig. 27 References: - Valencia/ES If the pneumothorax is resolved despite not receiving the right treatment, you should suspect that there is a communication between the airway and the pleural cavity, ie, a bronchopleural fistula. Hydropneumothorax. It occurs due to the coexistence in the same hemithorax of pleural effusion and pneumothorax. In this case it is possible to see the combination of the signs of both entities. Page 30 of 66

31 Fig. 28 References: - Valencia/ES Pleural thickening and pleural calcifications. Usually they translate chronic disease by exposure to agents such as asbestos. They manifest with pleural thickening and increased density. In the case of focal tumors, differential diagnosis must be made with other entities such as pleural tumors or metastases. Page 31 of 66

32 Fig. 29 References: - Valencia/ES Subcutaneous emphysema. It is produced by the introduction of air into the subcutaneous tissue or muscle between planes. In the second case, you can see the lines that form muscle fibers, being more evident in the case of the pectoral muscles. Page 32 of 66

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66 Conclusion Chest radiography is one of the most demanded tests in radiology emergency department, and it provides valuable information. Therefore essential the radiologist must know the radiological anatomy and the most common pathology, both acute and chronic, which can be found. Personal information References 1. Marano R, Liguori C, G Savino, Merlino B, L Natale, L. Bonomo Cardiac silhouette findings and mediastinal lines and stripes: CT scan radiograph and correlation. Chest May; 139 (5): Eisenhuber E, Schaefer-Prokop CM, Prosch H, Schima W. Bedside chest radiography. Respir Care Mar; 57 (3): Godoy MCB, Leitman BS, de Groot PM, Vlahos I, Naidich DP. Chest radiography in the ICU: Part 2 Evaluation of cardiovascular lines and other devices. AJR Am J Roentgenol Mar; 198 (3): Godoy MCB, Leitman BS, de Groot PM, Vlahos I, Naidich DP. Chest radiography in the ICU: Part 1, Evaluation of airway, enteric, and pleural tubes. AJR Am J Roentgenol Mar; 198 (3): JM Gibbs, Chandrasekhar CA, Ferguson EC, Oldham SAA. Lines and Stripes: Where Did They Go? -From Conventional Radiography to CT. RadioGraphics [Internet]. Jan [cited 2016 Mar 1]; 27 (1): Available from: abs/ /rg Page 66 of 66