Did you mark the retrosternal air space on your check-list?

Transcription

1 Did you mark the retrosternal air space on your check-list? Poster No.: P-0086 Congress: ESTI 2015 Type: Educational Poster Authors: A. Villanueva Marcos, M. Siddiqui, M. Escobar ; Cambridgeshire/UK, Barcelona/ES Keywords: Quality assurance, Patterns of Care, Education and training, Structured reporting, Plain radiographic studies, Thorax DOI: /esti2015/P-0086 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 31

2 Learning objectives 1. To illustrate the significance of routinely checking the retrosternal airspace. 2. To show its normal and abnormal appearance 3. To explain the distinctive features of lesions seen there Background Background: A check list is a comprehensive list of things to be done, or points to be considered, that is used as a reminder. Consistent results have been achieved by adhering to check lists. For example, a paper of New England Journal of Medicine demonstrated a 50% reduction in patient morbidity and mortality after the introduction of a checklist (1). Approximately 43.0 % of the total lung area is obscured on frontal chest radiographs (2). One of the major reasons for this is due to the overlap of various structures across the depth of the thorax, especially in the midline where there is overlap of the sternum, retrosternal space, mediastinal structures and the spine. One of the unique features of a lateral chest radiograph is the visualisation of the retrosternal air space which is not seen on a frontal projection. For that reason among others Lateral chest projection ought to be an essential review area while interpreting chest Xrays (3). The aim of this exhibit is to emphasize the importance of the retrosternal air space and hence the recommendation to include this on your checklist while reviewing chest radiographs. Here there is a case for you to solve Fig. 1 on page 3, Fig. 2 on page 3 Fig. 3 on page 4 The following slides show a. The illustration of normal appearance of retrosternal air space on lateral chest radiographs, followed by b. Cases demonstrating increase in the size of the retrosternal airspace, and finally c. Those cases where in the space is reduced or opacified. Page 2 of 31

3 Images for this section: Fig. 1: Fourty five y.o. man with hypogammaglobulinemia and persistent cough. What is your more likely diagnosis. 1.- Bronchiectasis 2.- Interstitial lung disease 3.- Normal 4. Other ANSWER AND EXPLANATION IN FOLLOWING FIGS Page 3 of 31

4 Fig. 2: Correct answer is 4. Features. Opacity in the retrosternal space seen on the lateral view (arrow) suggests an anterior mediastinal lesion that was not appreciable on the PA view. Most frequent anterior medistinal tumours are thymoma, germ cell tumours and lymphoma. Thymomas can be associated to hypogammaglobulinemia and other autoinmune conditions in a number of cases. A CT was performed for further evaluation Page 4 of 31

5 Fig. 3: Findings: CT chest, sagital reconstruction reveals well-defined egg-shaped soft tissue density mass anterior to the ascending aorta (yellow arrow) correlating to the opacity seen in the lateral view (red arrow). Patient surgical excision of the lesion. Diagnosis: Thymoma. This is the most frequent tumour arising from the anterior mediastinum and usually associated with paraneoplastic syndromes like myasthenia gravis, hypogammaglobulinemia and haemolytic anemia. Page 5 of 31

6 Imaging findings OR Procedure details Normal retroesternal air space The retrosternal air space also called anterior clear space is the dark area behind the sternum in the lateral view. It is limited anteriorly by the sternum and posteriorly by vascular structures (ascending aorta and main pulmonary artery) ( Fig. 4 on page 7 ). The size of the anterior clear space depends on the body habitus and age. It is narrow in thin individuals and in the elderly as the unfolded ascending aorta encroaches on the space ( Fig. 5 on page 8 ). Widened retrosternal space Patients with different condictions may show a widened retrosternal space ( Fig. 6 on page 9 and Fig. 7 on page 10 ). Narrowed or opacified retrosternal space The retrosternal space may be narrowed or opacified due to abnormal processes that may arise from the pleura/chest wall, mediastinum, or lung. Here there is another case for you to take a look ( Fig. 8 on page 13, Fig. 9 on page 11 and Fig. 10 on page 12 ). The retrosternal air space is important because abnormal processes in this area may not be depicted in the PA projection, being obscured by the overlap of the superior mediastinum. However they are easily visible in the lateral view, Extrapulmonary lesions (pleura/chest wall) affecting the retrosternal space usually arise from the sternum, pleura, intercostal space structures or mammary lymph nodes. They are well outlined and have obtuse angles with the characteristic appearance of extrapulmonary lesions. These lesions are situated immediately behind the sternum in the lateral view. (Figs. Fig. 11 on page 14, Fig. 12 on page 15, Fig. 13 on page 16 and Fig. 14 on page 17 ). Anterior mediastinal masses may also occupy the anterior clear space. They are located in the posterior aspect of the space, adjacent to the mediastinum. They are round and Page 6 of 31

7 not as well defined as extrapulmonary lesions. They may reach a significant size and still not be visible in the PA view (Figs. Fig. 15 on page 18, Fig. 16 on page 19and Fig. 17 on page 20 ). The majority arise from the thymus. Vascular lesions can also resemble anterior mediastinal masses ( Fig. 18 on page 21 ). The retrosternal area is occupied by the medial segments of both upper lobes, separated by the anterior junction line. Pulmonary infections or tumors can occur in this area. For that reason, it is not rare to see pulmonary lesions in the retrosternal air space, unsuspected in the PA view. They are usually well seen because they are surrounded by air (Figs. Fig. 19 on page 22, Fig. 20 on page 23, Fig. 21 on page 24, Fig. 22 on page 25 and Fig. 22 on page 25 Fig. 23 on page 26 ). Diffuse opacification of the retrosternal space can be due to big mediastinal masses, loculated pleural effusion and lung athelectasis ( Fig. 24 on page 27 and Fig. 25 on page 28 ). Images for this section: Page 7 of 31

8 Fig. 4: Normal retrosternal space. The anterior clear space is limited anteriorly by the sternum (red arrow) and posteriorly by the ascending aorta (dotted line) and main pulmonary artery (irregular blue line). Note how the lowest portion of the anterior ascending aorta wall that is calcified runs backward (pink arrow) in a different patient. The lowest posterior border of the retrosternal space is the mediastinal fat and main pulmonary artery (yellow arrows). Page 8 of 31

9 Fig. 5: Normal retroesternal space. The retrosternal space can be opacified when the lateral view is taken with the arms of the patient not well possitioned aimed upwards (arrow in A) or in elderly patients due to the unfloding ascending aorta. This feature is not very frequent in young patients. Axial CT of a different patient showing the area of lung hidden in the PA view (B, shaded rectangle), which represents the anterior clear space in the lateral view. Note a RLL patchy opacification due to a pulmonary haemorrhage. Page 9 of 31

10 Fig. 6: Three patients with widened clear anterior space. Pectus carinatum. Emphysma. Pericardial agenesia Page 10 of 31

11 Fig. 7: 40 y.o. man with pericardial defect with an unsual heart shape on the lateral view. Heart is shifted left and backward which leads to widening of the retrosternal air space as can be seen on these images (blue tracing). CT shows the pericardium terminates at a point (arrow). Page 11 of 31

12 Fig. 9: Findings: Lateral chest radiograph shows a large retrosternal extrapulmonary softtissue mass (B, white arrow), not seen in the PA view (A). In addition, there are smaller peripheral masses in the PA and lateral views (A,B, red arrows). Given the multiplicity of the lesions, fibrous tumor of pleura and sternal tumor can be excluded. The presence of several lesions is consistent with the diagnosis of multiple myeloma, which was later confirmed. Page 12 of 31

13 Fig. 10: Comparison with follow-up radiograph after autologous transplant treatment shows complete disappearance of the lesions (A and B, circles). A Initial film. B Three months later, after treatment. Diagnosis: IgD multiple myeloma. Page 13 of 31

14 Fig. 8: Patient with chest pain. What is your diagnosis? 1. Multiple myeloma 2. Tumor of sternum 3. Fibrous tumor of pleura 4. None of the above PLEASE SEE FOLLOWING FIGS FOR ANSWERAND EXPLANATION Page 14 of 31

15 Fig. 11: 45 y.o. woman with breast carcinoma. Routine control chest radiographs show an extrapulmonary lesion in the anterior clear space that is visible on the lateral chest view (B, arrow), but not on the PA film (A). Unenhanced CT shows the extrapulmonary lesion (C, arrow). Surgical diagnosis: fibrous tumor of pleura. Page 15 of 31

16 Fig. 12: Routine follow-up chest films in a 54 y.o. woman who had undergone surgery for breast carcinoma. The lateral view shows an extrapulmonary mass in the retrosternal air space (B, arrow) that was not visible in the PA radiograph (A). Comparison with previous radiographs taken a year earlier (see figure 13)... Page 16 of 31

17 Fig. 13: Same patient as fig 12. Comparison with previous radiographs taken a year earlier shows that the mass was present, albeit smaller (C and D, arrows). Sagittal CT confirms the extrapulmonary mass (E, arrow). Surgical diagnosis: metastatic internal mammary lymph nodes. Page 17 of 31

18 Fig. 14: 62 y.o. man with cough. Lateral chest radiograph shows a large retrosternal extrapulmonary soft-tissue mass narrowing the retrosternal air space (A, arrow), not seen in the PA view (B). CT demonstates an extrapleural lipoma (arrow in C). Page 18 of 31

19 Fig. 15: 57 y.o. woman with myasthenia gravis. PA radiograph shows double contour of the aortic knob (A, arrow). On the lateral view, a large round mass is seen in the anterior clear space (B, arrows). See fig 16 Page 19 of 31

20 Fig. 16: Same patient as fig 15. Axial and sagittal unenhanced CT images show an anterior mediastinal mass (C and D, arrows). Surgical diagnosis: thymoma. Page 20 of 31

21 Fig. 17: 63 y.o. man with evening fever and night sweats. Lateral chest radiograph shows opacificaion of the retrosternal air space in keeping with an anterior mediastinal tumor (arrow). Lymph node biopsy: Diffuse large B-cell lymphoma. PET CT for staging shows uptaking of the anterior mediastinal mass. Page 21 of 31

22 Fig. 18: 53 y.o. woman with osteoporosis and previous thoracic surgery. There is a diffuse opacification of the retrosternal space. A thin anterior curved radiolucent strip suggests an anterior mediastinal mass (white arrow). A sagittal bright blood MRI image shows a big ascending aortic dilatation (yellow arrow). Vascular lesions may appear as an anterior mediastinal mass in the lateral view. Page 22 of 31

23 Fig. 19: 84 y.o. man with dyspnea. Lateral chest radiograph shows a pulmonary nodule in the anterior clear space (B, arrow) that was not visible in the PA chest film (A). See fig 20 please Page 23 of 31

24 Fig. 20: Same patient as fig 19. Sagittal and axial CT confirm the presence of the nodule, which shows a calcium deposit (C, arrow) and fat (D, arrow). Hamartoma was suspected. Due to the patient's advanced age, no further procedures were undertaken. Page 24 of 31

25 Fig. 21: 72 y.o. man with moderate dyspnea. Lateral film discovers a pulmonary nodule in the retrosternal space (B, arrow) that is not visible in the PA film (A). The nodule is confirmed with CT (C, arrow). Final diagnosis: adenocarcinoma. Page 25 of 31

26 Fig. 22: 58 y.o. man with a painful mass in the left gastrocnemius muscle for the last two months, visible on US and MRI (A and B, arrows). PA chest film shows a double contour of the aortic knob (C,arrow) that was overlooked at the initialinterpretation. See Fig 23 please Page 26 of 31

27 Fig. 23: Same patient as in fig 22. Lateral film shows a large mass in the retrosternal air space (D, arrows), confirmed with CT (E, arrow). Final diagnosis: adenocarcinoma of lung with soft tissue metastasis. Page 27 of 31

28 Fig. 24: This 64 y.o. man was operated for aortic transplantation five days before the chest X ray was taken. Lateral chest X ray shows bilateral pleural effusion (white arrows in A) and a diffuse opacification of the retrosternal air space (red arrow in A). Chest drain noted. Later films show an air fluid level as a consequence of an anterior loculated hidroneumothorax (arrow in B). Page 28 of 31

29 Fig. 25: This 49 y.o. woman was operated and radiated form a left breast cancer 5 years before this chest X ray. The retrosternal space is diffusely opacified and a retrosternal band is seen in keeping with left upper lobe athelectasis (arrows in A). PA view shows left mastectomy and features of LUL athelectasis due to radiotherapy like the upwards shift of the left hilum and the left cardiac outline blurring (arrows in B). Page 29 of 31

30 Conclusion An addendum has been added at the end of the exhibit by the autors. Please be careful about reading it because it might be challenging. 1. It is essential to consistently review the retrosternal airspace on the lateral view as it may be the only projection revealing an abnormality. 2. Lesions may be compartmentalized as extrapulmonary by their sharp margins and obtuse angles. This lesions are located behind the sternum. 3. Mediastinal tumours are round and are located in the posterior part of the space. 4. Lung nodules are usually well seen because they are surrounded by air. 5. Big mediastinal masses, pleural effusion and lung athelectasis may show diffuse opacification. Addendum Summing up, abnormal appearance of this region may arise from lesions uprising from the pleura/chest wall, mediastinum, or the lungs which may not be depicted on the PA projection albeit very obvious on the lateral view. Reviewing previous chest X rays is the way to proceed when a suspicious lesion is seen while reporting chest X ray. A CT is usually suggested if the lesion is new and an inflammatory context does not exist. However, if a lesion is not obvious on a PA chest radiogrph the CT would not be recomended and that would invariably delay the diagnosis. It seems safe and reasonable to perform both PA and lateral views that would increase the detection rate as opposed to performing only PA views. Consequently this educational poster might persuade you that the lateral view should not only be as solving problem measure, but be considered as the other leg you always need for walking or the other eye you need for driving. Should not this safe measure of performing PA and lateral view routinely be implemented universally and promoted by the chest radiology societies? The ultimate aim of highlighting the retrosternal air space in this exhibit was to provide a thought provoking insight to the new as well as the experienced radiologists to include consistent and careful assessment of the retrosternal air space to their check list while assessing chest radiographs. Page 30 of 31

31 Authors are very grateful to Dr Caceres for his contribution. References 1.Haynes AB, Weiser TG, Berry WR et al. A surgical safety checklist to reduce morbidity and mortality in a global population. New Eng J Med 2010; 363: Chotas HG, Ravin CE. Chest radiography: Estimated lung volume and projected area obscured by the heart, mediastinum, anddiaphragm. Radiology. 1994#193: Proto AV, Speckman JM. The left lateral radiograph of the chest. Part One. Med Radiogr Photogr. 1979#55:3074. Personal Information avillanueva@nhs.net Page 31 of 31